Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
A research paper
Architecture of core-shell Ce-OMS-2@CeO2 catalyst and its SCR activity and SO2+H2O tolerance performance at low-temperature
DAI Geyu, PENG Yuewang, YU Chao, LÜ Bihong, WU Xiaomin, JING Guohua
 doi: 10.1016/S1872-5813(24)60465-2
Abstract(32) HTML(24) PDF 7825KB(0)
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It is a challenge to develop highly sulfur dioxide and water (SO2+H2O) resistance for the low-temperature selective catalytic reduction (SCR) catalysts of nitrogen oxide (NOx) in the non-electric-power industry. In this paper, core-shell and loaded type of Ce-OMS-2 complexes (Ce-OMS-2@CeO2 and CeO2/Ce-OMS-2) were successfully prepared. Their textural properties were characterized and catalytic performance were carried out. The results showed that the core-shell Ce-OMS-2@CeO2 material could maintain the mesoporous structure and significantly improve the mass transfer and adsorption of the reaction gas NO, thus improving the SCR efficiency. On the contrary, for the loaded CeO2/Ce-OMS-2 catalyst, large amounts of CeO2 deposited on the surface of Ce-OMS-2 and blocked the mesoporous structure. Furthermore, SO2 reacted with CeO2/Ce-OMS-2 to form lots of metal sulfate (manganese sulfate or cerium sulfate), which led to the deactivation of the active Mn sites. Therefore, the CeO2/Ce-OMS-2 catalyst exhibited the low SCR activity and poor SO2+H2O tolerance during the SCR reaction. We also clarify the reason for the anti-sulfur of core-shell Ce-OMS-2@CeO2 catalyst. In the presence of SO2 and H2O, SO2 could easily react with NH3 and H2O to produce ammonium bisulfate (NH4HSO4, ABS) on the surface of the Ce-OMS-2 and CeO2/Ce-OMS-2 catalysts. Then ABS can be physically deposited on the surface of the catalysts, thus blocking the active Mn sites to participate in the SCR reaction. Interesting, for the core-shell Ce-OMS-2@CeO2 catalyst, the formed ABS could significantly decomposed at low temperature, leading to the exposure of surface active Mn sites of the catalyst. Herein, it could maintain the efficient SCR performance over the Ce-OMS-2@CeO2 catalyst. A dynamic balance of ABS formation and decomposition was achieved over Ce-OMS-2@CeO2 even at low temperatures, which hindered the SO2 poisoning during the NH3-SCR reaction. As expected, the core-shell Ce-OMS-2@CeO2 catalyst showed excellent SCR performance and SO2+H2O resistance (~100% NO conversion in the temperature range of 100−200 ℃ without SO2, ~80% NO conversion for 4 h in the presence of SO2). This work provides an effective strategy for the development of efficient and stable Mn-based low-temperature SCR catalysts.
Preparation of Co0.5Cu0.5/CNR catalyst and its performance in hydrogen production by hydrolysis of ammonia borane
ZUO Youhua, LI Rong, HUA Junfeng, HAO Siyu, XIE Jing, XU Lixin, YE Mingfu, WAN Chao
 doi: 10.1016/S1872-5813(24)60442-1
Abstract(98) HTML(37) PDF 15881KB(8)
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Cobalt nitrate and copper nitrate was mixed to prepare solution A. Phenyldicarboxylic acid and N,N-dimethylformamide was mixed to prepare solution B. Co/Cu Lavashield skeleton series materials(Co/Cu-MIL precursors) was then synthesized by mixing the above two solution via solvothermal method. The precursor was further carbonized to produce the MOFs derivatives, i.e. bimetallic carbon nanorods(CoxCu1−x/CNR) catalysts. The morphology and composition of the catalysts were explored by SEM, TEM, XRD, XPS and other characterization means. The results showed that CoxCu1−x/CNR was successfully obtained after calcination of Co/Cu-MIL at high temperature. The activity of the catalyst was optimal when x=0.5, the solvothermal temperature of 120 °C and the calcination temperature of 650 °C. The TOF value of the Co0.5Cu0.5/CNR catalyst for the hydrolysis of ammonia borane for the production of hydrogen was 2718.21 h−1 with activation energy of 51.64 kJ/mol. The catalyst had good cyclic stability. Although the activity decreased, the conversion of AB still maintained 100% after 10 cycles.
A research paper
Catalytic conversion of biomass pyrolysis volatiles over composite catalysts of activated carbon and HY zeolite
XU Ji, WU Bowen, HAN Zhen, HU Haoquan, JIN Lijun
 doi: 10.1016/S1872-5813(24)60447-0
Abstract(116) HTML(22) PDF 2227KB(3)
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Bio-oil has complex compositions and high oxygen content, which restricts its high-value utilization. Commercial activated carbon (AC) and HY zeolite were used as composite catalysts to study their effect on pyrolysis volatiles from rice straw and poplar sawdust by changing the mixing models of two catalysts. The results showed that the loading models of AC and HY zeolite obviously affected the products distribution and bio-oil components. The lowest yield of bio-oil was obtained when HY zeolite and AC were mechanically mixed at a mass ratio of 1:1 (YACM). But the layered loading with YACM was beneficial to the deoxidation and aromatic hydrocarbon generation. Under the model of YACM, the aromatics content in rice straw and poplar sawdust bio-oil can be increased from 13.8% and 8.0% without catalyst to 56.4% and 53.1%, respectively. However, the layered loading with upper HY zeolite and lower AC (YTACL) was favorable for formation of phenolic compounds. The selectivity to monocyclic and bicyclic aromatic hydrocarbons followed the order of YTACL > ACTYL > YACM, and YACM > ACTYL > YTACL, respectively. Compared with HY zeolite, AC catalyst possessed smaller pore size and fewer acidity, and the active sites of AC were conducive to rearrangement of furan compounds to generate cyclopentanone, 2-cyclopentenone and methyl-cyclopentenone, and further rearrangement to form phenol. Therefore, the loading model of YTACL exhibited a promotion effect on the formation of phenol, cresol, toluene, ethylbenzene and p-xylene. The strong acidic sites of HY zeolite were favorable for the aromatization, so the loading model of ACTYL had good selectivity to the formation of naphthalene, methylnaphthalene, anthracene and pyrene. This work will provide a guide for products regulation from biomass pyrolysis and enrich aromatics and phenols in bio-oil.
review
Progress in application of binary composite oxides as supports for hydrodesulfurization catalysts
ZHOU Wenwu, HE Xinxin, TANG Xiaoyuan, ZHOU Anning, CHEN Zhiping, HUANG Zhihao, BAI Yexing
 doi: 10.19906/j.cnki.JFCT.2024019
Abstract(141) HTML(69) PDF 21042KB(15)
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Hydrodesulfurization (HDS) technique has been considered to play a crucial role in the clean, low-carbon, and diverse effective utilization of inferior crude distillates. The key to this technology is the development of catalyst with excellent catalytic performance. After decades of development, although the HDS performances for most sulfides of the non-noble metal supported catalysts have been greatly improved, but their catalytic activities for highly refractory sulfides are still limited due to the over-strong metal and support interaction (MSI), insufficient acidity, poor textural properties and damnable surface environments. Researches across the world made a lot of efforts to solve the above problems and the developing of novel support candidates is considered as the most efficient solution. In this review, we summarized the developments for the applications of binary Al2O3 based composite oxides and binary TiO2 based composite oxides as support for hydrodesulfurization catalyst and systematically analyzed the effect of the second component on both the properties of the catalyst, mainly focused on the acidity property, MSI, pore structures and the catalytic performances, and the applications of the corresponding catalysts in thiophene, dibenzoethiophene, 4,6-dimethyldibenzothiophene and inferior diesel fuels. It was concluded that both the MSI and the acidity can be effectively modulated after incorporation of appropriate amount of SiO2 into Al2O3 support, which can be attributed to the successful formation of Al−OH−Si linkages over the support surface and thus prevented the formation of excessive Mo−O−Al bonds, resulted in the enhanced hydrogenation activity of the corresponding catalyst which further contributed to the excellent HDS performance. The introduction of ZrO2 into Al2O3 support can also modulate the MSI and the acidity due to the similar reasons, except for that, researchers also found that the reducibility of the active phase precursors can be effectively enhanced, which is favorable for the formation of more active phases. Introducing small amounts of MgO into Al2O3 can effectively enhance the dispersion of active metals over the support surface and promote the formation of Ni(Co)−O−Mo(W) precursors, then acquiring more Ni(Co)Mo(W)S active phases. The introducing of B2O3 can effectively lower the density of hydroxyls and promote the formation of octahedral coordinated Mo species which can be easily sulfided. In summary, the introduction of the second component into Al2O3 successfully overcame the disadvantages such as the solely acid type and the strong interaction between the metal and the support materials over Al2O3 based hydrodesulfurization catalyst, and the advantage of high specific surface area remained. The addition of SiO2 into TiO2 support can effectively improve both the acidity property and the stability of the catalyst, moreover, the specific surface area of the catalyst can also be enlarged after SiO2 addition. After introduction of ZrO2 into TiO2, the density of hydroxyl groups over the support surface decreased, the dispersion of active metals improved and the high stacking Mo(W)S2 slabs formed, thus enhanced the direct desulfurization pathway selectivity. Addition of basic MgO into TiO2 support can enhance the MSI and thus improve the dispersion of active metals over the support surface due to the strong interaction between the basic-acidic pairs. In summary, the introduction of the second component not only improved the thermal stability and the specific surface area, but also modulated the acidity properties. The main factor causing these changes is that the introduction of the second component profoundly changed the hydroxyl environments. Which further improved the anchorage and dispersion of the precursors over the support surface and promoted the formation of more NiMo(W)S active phase, resulted in the enhanced hydrodesulfurization performances of the corresponding catalysts.
A research paper
Preparation of ultra-microporous waste paper carbon aerogel and its CO2 adsorption performance
GU Jinyang, ZHANG Xiong, ZHANG Junjie, SHAO Jingai, ZHANG Shihong, YANG Haiping, CHEN Hanping
 doi: 10.19906/j.cnki.JFCT.2024016
Abstract(89) HTML(30) PDF 6750KB(15)
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The intensification of climate change requires the development of greener and more efficient carbon abatement technologies and products. Conventional CO2 carbonaceous adsorbent materials derived from solid waste and biomass feedstocks are poorly adsorbed and often require additional activation pore making and functional group introduction to enhance the adsorption performance of the porous carbon, which inevitably results in further growth of the process and further increase in energy consumption. In the work carried out in this paper, different kinds of waste paper were used as raw materials, and after a simple pretreatment and sol-gel carbonization process, highly developed microporous hierarchical porous carbon aerogels were prepared; moreover, KOH could be introduced in situ and activation pore-making could be accomplished synchronously during pyrolysis, which avoided the additional energy consumption of the two-step method. Thermogravimetric (TG), scanning electron microscopy (SEM), specific surface area and pore size analyzer (BET), Fourier transform infrared spectrometer (FT-IR) and fixed bed adsorption rig were used to characterize and test the thermal weight loss properties of the waste paper aerogels, the physicochemical properties of the waste paper carbon aerogels and the CO2 adsorption properties, respectively, and the results show that the main thermal weight loss process of the waste paper aerogels occurs at around 300 ℃. and is accompanied by the appearance of miscellaneous peaks of heat loss in the low pyrolysis temperature region, and the final mass residual rate is slightly higher than that of cellulose. Scanning electron microscopy showed that the pore structure was well developed and relatively homogeneous, and the surface openings showed a honeycomb-like structure. The printing paper carbon aerogel DYZ-800 prepared at a pyrolysis temperature of 800 ℃ has an ultra-high specific surface area of 1369.94 m2/g (94.28% of microporous specific surface area), a pore volume of 0.59 cm3/g (85.34% of microporous pore volume), and a pore-size distribution that is close to the kinetic diameter of CO2 molecules (0.4−0.8 nm and containing a large number of super-micropores with a size of 0.7 nm). The results of FT-IR tests revealed the effects of different waste paper types and pyrolysis temperatures on the carbon aerogel skeleton and chemical groups of waste paper, with sample DYZ-800 having a more stable carbon skeleton and a relatively high content of carbon-oxygen (C−O) groups. The maximum CO2 adsorption capacity of DYZ-800 without modification was 247 mg/g at 0 ℃ (1 bar) and 151 mg/g at 25 ℃ (1 bar), and the CO2/N2 adsorption selectivity was 11. The average fluctuation after 7 adsorption and desorption cycles was less than 5%, which showed good regeneration stability. The capture of CO2 at 10% flue gas concentration on a fixed-bed adsorption bench could also reach 42 mg/g (25 ℃, 1 bar). Among the three different adsorption kinetic models selected, the Bangham pore diffusion model had an excellent fit, demonstrating the great contribution of the well-developed pore structure of waste paper carbon aerogels in the CO2 kinetic adsorption process. Taken together, these results show that the waste paper carbon aerogel possesses excellent physicochemical properties, and the presence of a large number of micropores (especially ultra-micropores) enables it to exhibit excellent CO2 adsorption performance, which is superior to that of conventional solid waste and biomass-based carbon materials. All these indicate that the carbon aerogel prepared in this work has great advantages in carbon capture and potentials for further improvement, and this work also provides new ideas for solid waste disposal and resource utilization.
Research on coking performance of ethylene residue pitch components
ZHANG Tongtong, ZHU Huihui, ZHU Yaming, HU Chaoshuai, LV Jun, CHENG Junxia, BAI Yonghui, ZHAO Xuefei
 doi: 10.1016/S1872-5813(24)60435-4
Abstract(86) HTML(55) PDF 5784KB(1)
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Ethylene residue pitch (the heavy component in ethylene residue tar) was widely used as the preferred raw material for preparing petroleum based artificial carbon materials with the characteristics of high carbon content, high aromaticity, and low heteroatom (S, N) content. In order to a detailed study on the coking properties of ethylene residue pitch, 8 components of ethylene residue pitch (four soluble and four insoluble components) were obtained by extraction and separation method. Factually, methanol, n-butanol, n-hexane, and dimethyl sulfoxide were selected as the solvents to extract and separate the ethylene residue pitch. A series of petroleum based pitch coke were gained by the thermal conversion and carbonization treatment (thermal conversion temperature and carbonization temperature were 500 and 1400 ℃, respectively) of each pitch components. The basic physical properties of ethylene residue pitch components were studied using infrared spectroscopy, thermogravimetric analysis, and 1H-NMR. The micro-structure of a series of petroleum based pitch coke was studied by polarizing microscopy, X-ray single crystal diffraction, Raman spectroscopy, scanning electron microscopy. The results shown that: The aromaticity of insoluble components in ethylene residue pitch is slightly higher than that of soluble components, and the branching chains of insoluble components are slightly less than those of soluble components. The microstrength of ethylene residue pitch coke obtained by thermal conversion and carbonization of insoluble components is higher than that of ethylene residue pitch coke obtained by soluble components, and the true density of ethylene residue pitch coke HS-C is as high as 2.0554 g/cm3.
A research paper
Ce-doped cobalt-based hydroxide assisted with low-temperature molten salt for industrial oxygen evolution reaction
WANG Fuli, LÜ Qianxi, DONG Yiwen, XIE Jingyi, WANG Zhicai, DONG Bin, CHAI Yongming
 doi: 10.1016/S1872-5813(24)60456-1
Abstract(63) HTML(33) PDF 8691KB(3)
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Developing low cost and high-performance oxygen evolution electrocatalysts is significant to improve the efficiency of water electrolysis for large-scale hydrogen production. Cobalt hydroxide is a promising electrocatalyst for oxygen evolution reaction (OER), but its poor conductivity and activity seriously restrict the practical application. A simple one-step low temperature molten salt method was applied to successfully synthesize the Ce-doped cobalt hydroxide nitrate (Ce-CoNH/CF), which exhibits outstanding OER performance with a low overpotential of 448 mV at the current density of 1000 mA/cm2 in 1 mol/L KOH. The remarkable performance of Ce-CoNH/CF electrode in OER may be the comprehensive result of fast reaction kinetics, large electrochemical active specific surface area (ECSA) and small charge transfer resistance (Rct) as revealed by the Tafel, cyclic voltammetry (CV) and electrochemical impedance spectra (EIS) analysis. Under the simulated industrial test conditions (6 mol/L KOH, 70 ℃), the Ce-CoNH/CF electrode still displays excellent OER performance.
A research paper
The study of design and performance improvement of catalysts for the stepwise production of bicyclohexane from benzene and cyclohexene
LIU Ruilin, WANG Sen, MENG Fanchun, LI Zhuo, YANG Huimin, ZHAO Shichao, QIN Yong, ZHANG Bin
 doi: 10.1016/S1872-5813(24)60457-3
Abstract(101) HTML(30) PDF 2473KB(8)
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Bicyclohexane is a hydrogen storage reagent with high hydrogen density and low boiling point. Compared with the hydrogenation of biphenyl, the alkylation of benzene and cyclohexene to cyclohexylbenzene and hydrogenation is a promising way to prepare cyclohexane on a large scale. The research and development of high-efficiency cyclohexyl benzene hydrogenation catalyst should be further developed based on mature alkylation technology. This paper used an acidified USY molecular sieve to catalyze the alkylation of benzene and cyclohexene to cyclohexylbenzene, which achieved 100% conversion and selectivity. Furthermore, Pt/TiO2/γ-Al2O3 catalyst is prepared by pre-deposition TiO2 film of different thicknesses on γ-Al2O3 surface and then supported with platinum particles by Atomic layer deposition (ALD). The role of TiO2 film in improving the cyclohexylbenzene hydrogenation performance of the catalyst is studied. TEM, CO pulse chemisorption, CO-DRIFTs, quasi-in situ XPS, H-D exchange, and H2-TPR characterization show that compared with Pt/γ-Al2O3, TiO2 thin films on Pt/TiO2/γ-Al2O3 do not change the dispersion of Pt particles, but can form new Pt-TiO2 interactions. The hydrogenation performance of cyclohexylbenzene was improved by increasing the electron density and the proportion of planar active sites on the surface of platinum and reducing the energy barrier of hydrogen spillover. The research provides theoretical support for further bicyclohexane organic liquid hydrogen storage reagent development. The relevant metal-support interaction regulation strategy can be applied to the development of efficient catalysts for other aromatic molecules hydrogenation.
Density functional theory study of adsorption of As2O3 on CeO2 surface by Fe, La doping and oxygen defects
LU Kunpeng, ZHANG Kaihua, ZHANG Kai
 doi: 10.19906/j.cnki.JFCT.2024005
Abstract(85) HTML(77) PDF 10400KB(21)
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Density functional theory (DFT) was used to study the adsorption behavior of As2O3 (g) on iron and lanthanum doped CeO2 (110) and oxygen-deficient LaCeO (110) surfaces, and the reasons for the arsenic adsorption capacity of LaCeO surface was significantly higher than that of FeCeO surface was explored. The results show that the adsorption effect of As2O3 (g) is closely related to the number of adsorption sites, adsorption energy, bond length and charge transfer amount. Ce and O atoms on the surface of pure CeO2 are both active sites, and the adsorption is mainly chemisorption, the absolute adsorption energy is greater than −4.22 eV, and the charge transfer amount is (−0.19)−(−0.31) e. As2O3 has a negative charge and acts as a surface accepter, while CeO2 loses electrons and has a positive charge on the surface, which acts as a surface donor. The number of free electrons in the CeO2 conduction band gradually decreases, the conductivity decreases, and it is difficult to provide more electrons continuously, so the adsorption amount is small. Two adsorption sites are added on the surface of FeCeO (110): Fe top site and Bridge-2 Bridge site, where Fe top site is chemical adsorption and Bridge-2 Bridge site is physical adsorption. The gap doping of Fe changes the electron distribution and lattice structure on the surface of FeCeO, resulting in obvious deformation of the lattice and reducing the difficulty of bonding, thus increasing the configurational adsorption energy of some configurations. However, it does not change the charge transfer direction between As2O3 and FeCeO, thus not changing the surface adsorption form of As2O3. As2O3 is still adsorbed in the form of negative ions, which plays the role of surface acceptor, and the adsorption amount is small. LaCeO (110) has three new adsorption sites: La top site, Bridge-3 Bridge site and Hollow-2 vacancy, among which the La top site and Bridge-3 Bridge site are chemical adsorption. La doping changes the charge transfer direction between As2O3 and LaCeO, resulting in positive ion adsorption of As2O3 with electron loss and surface donor function. The electrons on the surface of LaCeO play the role of surface acceptor. With the progress of adsorption, the number of free electrons in the conduction band increases, and the conductivity increases. Therefore, the adsorption capacity of As2O3 on the surface of LaCeO increases. In the absence of O2, the number of chemical bonds and bond energy formed on the surface of LaCeO (110) with single O defect are smaller than those on the surface of LaCeO and the charge transfer on the surface of the defect is less, so the adsorption energy decreases. In this case, As2O3 obtains electrons and acts as the surface donor, and the adsorption capacity is lower than that on the complete LaCeO surface. In the presence of O2, the adsorption energy and charge transfer number increase in the ortho-configuration after O2 supplementation with O defect. As2O3 is positively adsorbed in ionic form, and the adsorption energy is also higher than that on the intact LaCeO surface. The adsorption capacity of As2O3 is better than that on the LaCeO surface, indicating that O defect is conducive to the adsorption of As2O3 in the presence of O2.
A research paper
Pore structure modulation of Cu-ZnO-ZrO2 catalysts for methanol production from CO2 hydrogenation
LI Zhonglin, WANG Yuhao, ZHENG Yane, JIANG Lei, LI Zhiqiang, WANG Chunliang, HE Lun, LI Kongzhai
 doi: 10.19906/j.cnki.JFCT.2024021
Abstract(65) HTML(36) PDF 28646KB(7)
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Copper-based catalysts have attracted much attention for the hydrogenation of carbon dioxide (CO2) to synthesize methanol, however, problems including low methanol selectivity, easy sintering of the active components of the catalysts, and poor stability are commonly encountered. In this study, Cu-ZnO-ZrO2 (CZZ) catalysts with macroporous and nonporous morphology were prepared by the colloidal crystal template method and the conventional co-precipitation method, respectively, and their CO2 hydrotreating to methanol performance was investigated. In the colloidal crystal template method, polymethyl methacrylate (PMMA) was chosen as the template structure, and the diameter size of the macropores was regulated by controlling the PMMA particle size, so that samples with different pore sizes were prepared. The results show that compared with the bulk samples prepared by the co-precipitation method, the samples prepared by the template method have a permeable macroporous structure, and due to the special three-dimensional ordered structure of the macroporous holes, the ZnO can be uniformly dispersed around the pore wall formed by Cu, which effectively prevents the growth of ZnO particles. Moreover, by changing the pore size of the macropores, the regulation of ZnO particle size can be realized, and smaller ZnO particle size shows more excellent catalytic performance. Among them, excellent catalytic performance and application potential were demonstrated on a (CZZ-55) sample with a pore size of 55 nm, a ZnO particle size of 14.5 nm, a CO2 conversion of 14.83%, a methanol selectivity of 78.8%, and a methanol yield up to 345.8 g/(kg·h) which is 1.52 times higher than the performance of the nonporous catalyst. The results of in situ diffuse reflectance infrared Fourier transform spectroscopy showed that the methanol synthesis from CO2 hydrogenation over the CZZ catalyst followed the formate pathway, and the ZnO-ZrO2 interface was the active site for CO2 adsorption and activation. Moreover, the three-dimensional ordered macroporous structure provides an ideal “pedestal” for the creation of abundant interfaces and active sites, which contributes to the formation of more dispersed ZnO-ZrO2 active sites, thus significantly increasing the CO2 conversion rate. At the ZnO-ZrO2 interface, CO2 can be stably adsorbed and activated to form carbonates and bicarbonates and to adsorb formates generated by subsequent hydrogenation reactions. It is worth noting that the pore size of the catalyst has a significant effect on the conversion of the reaction intermediates. Specifically, smaller pore sizes were more favorable for the formation of the key intermediates formate and methoxide, which provided the necessary conditions for effective conversion to methanol. In addition, samples with three-dimensionally ordered macroporous structures play a unique role in the CO2 hydrogenation to methanol process compared with the non-porous bulk samples. The three-dimensional ordered macroporous structure of the pores provides a “high-speed channel” for the rapid diffusion of the reaction products (water vapor and methanol), which effectively inhibits the toxicity of the by-products of CO2 hydrogenation, water vapor, to the active components of Cu and ZnO, and improves the stability of the catalyst to a large extent. Under the actual reaction conditions of 4 MPa and 220 ℃, no obvious deactivation phenomenon was observed within 600 h, and the catalyst has a promising application. This work emphasizes the importance of catalyst morphology for the design of catalysts for methanol synthesis from CO2 hydrogenation and provides new ideas for the controlled synthesis of efficient methanol synthesis catalysts.
A research paper
Study on the catalytic performance of Fe in-situ modified small crystallite Silicalite-1 zeolite in Chichibabin condensation reaction
TAO Jinquan, JIA Yijing, BAI Tianyu, HUANG Wenbin, CUI Yan, ZHOU Yasong, WEI Qiang
 doi: 10.1016/S1872-5813(24)60443-3
Abstract(80) HTML(30) PDF 5618KB(5)
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Pyridine and its derivatives, collectively referred to as pyridine bases, are widely used in industries such as pesticides and pharmaceuticals, serving as crucial intermediates in the chemical industry. In recent years, with the development of the pesticide and pharmaceutical industries, the demand for pyridine bases has rapidly increased. The Chichibabin condensation reaction is the most commonly route for industrial production of pyridine bases. Currently, the most used ZSM-5 zeolite catalyst is limited by the instability of its silicon-aluminum framework structure, resulting in a short active reaction cycle (5 h). To address this limitation, this study selected the thermally stable and hydrothermally stable Silicalite-1 zeolite. Polyvinylpyrrolidone (PVP) was employed as a colloidal dispersant and Fe was introduced into the MFI framework through in situ modification during the hydrothermal synthesis of zeolite. The influence of PVP dosage, template agent dosage, and other crystallization conditions on the crystallinity, pore structure, and acidity of Silicalite-1 zeolite products was investigated using XRD, SEM, TG, and N2 adsorption-desorption measurement. The acidity of Fe-modified Silicalite-1 zeolites was characterized using NH3-TPD, Py-IR, FT-IR, and XPS. These results indicated that the introduction of seed crystals effectively reduced the particle size of the zeolite to about 200 nm. Fe-modified Silicalite-1 displayed a disk-like morphology with excellent crystal dispersion. The highest relative crystallinity of the zeolite reached 103% with 15% seed crystal input and 3.75% PVP addition. The Fe-modified Silicalite-1 possessed a significantly enhanced abundance of both Lewis (L) and Brønsted (B) acid sites, resulting in an increase in the initial activity from 66% to 85% for the pyridine bases synthesis through the Chichibabin condensation. Compared to ZSM-5, Fe-modified Silicalite-1 exhibited superior catalytic stability, maintaining the total carbon conversion and pyridine bases yield above 66% and 40%, respectively, over a 15 h reaction period. Furthermore, the strategy proposed in this study, employing polyvinylpyrrolidone as a colloidal stabilizer to modify Silicalite-1 zeolite, could significantly broadened the application prospects of weakly acidic pure silica zeolites in the field of acid catalysis. This approach has demonstrated significant scientific value and industrial potential.
A research paper
Synthesis of γ-valerolactone through coupling of methyl levulinate hydrogenation with aqueous phase reforming of methanol over Pt/CoxAl catalyst
LÜ Zexiang, ZHU Shanhui, DONG Mei, QIN Zhangfeng, FAN Weibin, WANG Jianguo
 doi: 10.1016/S1872-5813(24)60453-6
Abstract(69) HTML(37) PDF 6953KB(2)
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The synthesis of high-value γ-valerolactone (GVL) from biomass-derived methyl levulinate (ML) conventionally requires a high-pressure hydrogenation process, which incurs significant costs and safety concerns. This study proposes an innovative approach to produce GVL by integrating ML hydrogenation with aqueous phase reforming of methanol (APRM) using Pt/CoxAl catalysts, thereby eliminating the need for an external hydrogen source. The influence of catalyst composition, methanol concentration, and reaction temperature on catalytic performance has been carefully examined. The results suggest that Pt/Co1Al demonstrated exceptional activity, yielding up to 98.2% GVL, and maintaining stable performance over multiple cycles. Characterization results revealed that Pt0 facilitates both APRM and ML hydrogenation, while Brønsted acid sites catalyze the hydrolysis of ML and lactonization of intermediates. The synergy between Pt0 and Brønsted acid sites is essential for GVL formation. The appropriate amount of Co not only enhances Pt dispersion but also increases Brønsted acid sites, thereby boosting catalytic efficiency. This work offers a sustainable and economically feasible strategy for transforming biomass derivatives into valuable fuels and chemicals.
A research paper
In situ reduction and carbonation of organogel containing Fe and Mn and their catalytic performance in Fischer-Tropsch synthesis
LI Changxiao, LI Jie, LU Qichao, LIU Jianchao, LIU Lei, DONG Jinxiang
 doi: 10.19906/j.cnki.JFCT.2024015
Abstract(94) HTML(39) PDF 10646KB(11)
Abstract:
Light olefins constitute crucial chemical commodities primarily obtained from petroleum through naphtha cracking processes. Given China's energy landscape, characterized by a scarcity of oil, limited natural gas resources, and substantial coal reserves, leveraging coal for synthesizing light olefins emerges as a strategic pathway. This approach not only reduces reliance on petroleum resources but also enhances the value proposition of coal reservoirs. Coal-to-olefin conversion pathways encompass both direct (FTO) and indirect (MTO) methodologies. Notably, the FTO route stands out as a more efficiently and economically viable strategy for coal resource utilization. Fischer-Tropsch synthesis relies on iron carbides as active sites, posing a challenge in elucidating the distinct roles of single-phase iron carbide species within catalysts derived from CO or syngas. To address this challenge, we synthesized a range of organogel precursors incorporating Fe and Mn species. Subsequent in-situ reduction and carbonization of Fe species within the gel matrix under high-temperature conditions in an argon environment yielded Fischer-Tropsch catalysts featuring varying contents of θ-Fe3C species. The structural composition, surface properties and electronic valence states of the active species of the catalysts were systematically characterised and analysed by XRD, N2 adsorption, Raman spectroscopy, CO-TPD, CO2-TPD, XPS, and TEM measurements. The resulting catalysts exhibited a composite composition comprising graphitic carbon, θ-Fe3C, Fe0, and (FeO)0.497(MnO)0.503 phases. Catalysts lacking Mn promoter demonstrated superior catalytic activity (91.4%) but lower selectivity towards light olefins (16.0%), with the emergence of the χ-Fe5C2 phase post-reaction. This was attributed to the χ-Fe5C2 species had higher intrinsic catalytic activity than θ-Fe3C species. For the catalysts with Mn promoter, the structure of the catalysts and the species of the physical phase remained stable after the Fischer-Tropsch reaction. We believed that Mn promoter played the role of structural promoter and displayed a stabilizing role in the phase structure of the catalysts. Fine-tuning the content of θ-Fe3C within the catalysts by varying Mn promoter addition enabled a deeper exploration of the correlation between catalytic performance and content of θ-Fe3C. Fine-tuning the content of θ-Fe3C within the catalysts by varying Mn promoter addition enabled a deeper exploration of the correlation between catalytic performance and content of θ-Fe3C. Quantification of θ-Fe3C content via XRD revealed that content of θ-Fe3C of the FeMn10 catalysts exhibited approximately 54.5%, resulting in a CO conversion rate of 57.3% and light olefins selectivity of 37.1%. In contrast, content of θ-Fe3C of the FeMn2 catalysts displayed roughly 19.3%, yielding a CO conversion rate of 10.7% and light olefins selectivity of 24.1%. These findings underscored the pivotal role of θ-Fe3C as the catalytic core in Fischer-Tropsch reactions, positively correlating with both CO conversion and light olefins selectivity. In addition, the FeMn catalysts exhibited low CO2 selectivity attributed to the hydrophobic nature of carbon material generated from organic gel pyrolysis. This phenomenon curbed iron carbide oxidation by water, thereby reducing the formation of Fe3O4 species and exerting a suppressive effect on the water-gas shift (WGS) reaction. θ-Fe3C catalysts exhibited excellent light olefins selectivity and low CO2 selectivity in Fischer-Tropsch synthesis, and had potential for industrial applications.
A research paper
Effect of Mg modification on the catalytic performance of zinc malachite for methanol synthesis
YUAN Zhiguo, ZHANG Fan, YANG Shili, XU Xiaoying, LIU Chenyang, QIU Zhengpu, WEI Wei
 doi: 10.1016/S1872-5813(24)60455-X
Abstract(92) HTML(24) PDF 2295KB(13)
Abstract:
The complex conditions of methanol production from coke-oven gas have brought challenges to the copper-based methanol synthesis catalyst. In this work, a series of zinc-malachite samples with different Mg contents were prepared. The zinc-malachite and calcined samples were characterized by in-situ X-ray diffraction (XRD), thermogravimetry-mass spectrometry (TG-MS), N2 physical adsorption, H2 programmed temperature reduction (H2-TPR), CO2 programmed temperature desorption (CO2-TPD) and other methods. The effects of Mg addition on the structure of zinc-malachite and its catalytic performance of methanol synthesis were investigated. The results showed that the addition of Mg increased the degree of Cu substitution inside the zinc-malachite structure and promoted the formation of high temperature carbonates in the catalyst after roasting. With the increase of Mg content, the specific surface area of the calcined catalyst increased gradually, and the Cu grain size decreased simultaneously. In-situ XRD results showed that a small amount of Mg could effectively inhibit the growth of copper grain size during the heat treatment. The evaluation showed that the initial activity of the catalyst increased first and then decreased with Mg addition, and the activity of the Mg-doped catalyst remained at a relatively high level after heat treatment. The appropriate Mg addition is beneficial to the initial activity and thermal stability of Cu-based methanol synthesis catalyst.
A research paper
Preparation of silicon foam supported CoMn catalysts and their catalytic performances in higher alcohol synthesis via syngas
DU Xin, ZHANG Mingwei, FANG Kegong
 doi: 10.1016/S1872-5813(24)60444-5
Abstract(98) HTML(40) PDF 3662KB(10)
Abstract:
A series of silicon foam supported CoMn catalysts were prepared using impregnation, precipitation, and hydrothermal methods. Combining the characterization techniques such as XRD, H2-TPR, N2 physical adsorption, TEM, and XPS, the effect of different catalyst preparation methods on the catalytic performance in the synthesis of higher alcohols from syngas was investigated. Research has shown that there are Co2+(Co2C) and Co0 species on the surface of the catalyst. The active sites of Co2C-Co0 on the surface of the catalyst prepared by hydrothermal synthesis have a good synergistic effect, which is conducive to the generation of alcohols. A higher proportion of Co2C also promotes the associative adsorption and insertion of CO, resulting in the highest alcohol selectivity. Under the reaction conditions: t=260 ℃, p=5.0 MPa, GHSV=4500 h−1, H2/CO(volume ratio)=2∶1, the catalyst exhibited the best reaction performance to achieve CO conversion of 11.1%, total alcohol selectivity of 34.7%, and C2+OH selectivity of 34.5%.
A research paper
Effect of Rh loading on the selectivity to methanol and ethanol in the hydrogenation of CO2 over the Rh/CeO2 catalyst
ZHENG Ke, LIU Bing, XU Yuebing, LIU Xiaohao
 doi: 10.1016/S1872-5813(24)60450-0
Abstract(57) HTML(52) PDF 1401KB(16)
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The capture and hydrogenation of CO2 into high-value chemicals such as alcohols is one of the important ways to reduce CO2 emission and achieve carbon resource recycling. In this work, the catalytic performance of Rh/CeO2 catalyst in the CO2 hydrogenation was investigated; with the help of various characterization methods including XRD, Raman, H2-TPR, CO2-TPD, CO-DRIFTS and XPS, the influence of Rh loading (0.1%–2.0%) on the catalytic activity of Rh/CeO2 and product selectivity in the CO2 hydrogenation was revealed. The results indicate that for the hydrogenation of CO2 at 250 °C and 3.0 MPa over the Rh/CeO2 catalysts, ethanol is the major product at a low Rh loading of 0.1%. With the increase of Rh loading, the conversion of CO2 increases, but accompanied by a decrease in the selectivity to ethanol; when the Rh loading reaches 2.0%, the main product turns to be methanol. It seems that the difference of various Rh/CeO2 catalysts with different Rh loadings in the product selectivity for the CO2 hydrogenation is ascribed to their difference in the structural and electronic properties of Rh; atomically dispersed Rh+ species favor the stabilization of CO* and its subsequent C–C coupling with CH3* to form ethanol, whereas metallic Rh clusters facilitate the hydrogenation of CO* to produce methanol.
A research paper
Effect of ZSM-5@Silicalite-1 zeolites prepared by solid phase epitaxial growth method on CO2 hydrogenation and toluene alkylation reactions
JIA Yimin, NIU Pengyu, JIA Litao, LIN Minggui, GUO Heqin, XIAO Yong, HOU Bo, LI Debao
 doi: 10.19906/j.cnki.JFCT.2024012
Abstract(124) HTML(34) PDF 6771KB(12)
Abstract:
CO2 hydrogenation to synthesize high value-added aromatics is of great significance to alleviate the energy climate problem caused by CO2 emission. It is generally believed that the reaction course of CO2 hydrogenation of toluene coupled with alkylation to produce xylenes is as follows: firstly, CO2 reacts with H2 to produce methanol intermediates, and then the methanol intermediates react with toluene on zeolite catalysts to produce para-xylene (PX) by alkylation. According to the reaction pathway, it is necessary to construct a bifunctional catalyst with synergistic matching of the two process conditions to simultaneously realize the hydrogenation of CO2 to methanol intermediate and the alkylation of the intermediate and toluene to generate para-xylene. The ZnZrOx/ZSM-5 catalytic system, in which the ZnZrOx has strong thermal stability and CO2 activation ability, and the ZSM-5 has a good morphology selectivity for PX, is considered to be a promising CO2 hydrogenated toluene coupled alkylation catalyst. However, this system still suffers from low PX selectivity, mainly due to the presence of non-selective acidic sites on the outer surface of the zeolite or near the pore orifice, which leads to the generation of side reactions, such as deep methylation and toluene isomerization, and reduces the selectivity. In this paper, ZSM-5@Silicalite-1 zeolites were prepared by epitaxial growth of Silicalite-1 on the surface of ZSM-5 using solid-phase synthesis. At the same time, the highly active oxide ZnZrOx was prepared and physically mixed with ZSM-5@Silicalite-1 to form a ZnZrOx/ZSM-5@Silicalite-1 bifunctional catalyst to study the catalytic performance of CO2 hydrogenation coupled with toluene alkylation. Compared with the ZnZrOx/ZSM-5 catalyst, the modified zeolite improved the para-xylene (PX) selectivity. The effect of crystallization conditions (silicon source, crystallization process, and number of crystallizations) on the epitaxial growth of Silicalite-1 from ZSM-5 was investigated, as well as the effect of the thickness of the Silicalite-1 passivation layer on the performance of the reaction between carbon dioxide hydrogenation and toluene alkylation. The ZZO/1:3.5Z5-Na-SiO2 catalyst showed a toluene conversion of 12.0%, a xylene selectivity of 77.4%, and a PX selectivity of 73.4% in xylene under 400 ℃ and 3 MPa reaction conditions. The structure and acid properties of the zeolites were investigated in detail by SEM, XRD, N2 adsorption-desorption, XPS, NH3-TPD and Py-FTIR characterization, and the results show that the selectivity of para-xylene (PX) can be effectively improved by solid-phase epitaxial growth to extend the pore channels of ZSM-5, increase the diffusion resistance of m-xylene (MX) and o-xylene (OX), and passivate the acidity of the outer surface at the same time. This method abandons the disadvantage of previous modification of molecular sieves by blocking the pores to narrow the orifice, and upgrades the product selectivity while ensuring the catalyst activity.
A research paper
Preparation of PdAg/CDs-ZSM-5 catalyst and performance study on furfural aqueous phase hydrogenation-rearrangement to cyclopentanone
LIU Li, BAO Guirong, LUO Jia, GAO Peng, JI Xuewu, DENG Wenyao
 doi: 10.19906/j.cnki.JFCT.2024014
Abstract(78) HTML(40) PDF 11243KB(12)
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With the huge demand for fossil resources and increasing energy consumption, the utilization of biomass as a renewable alternative to the production of chemicals and fuels has attracted much attention. Furfural (FFA), as an important biomass-based derived carbonyl compound, can be industrially produced on a large scale from lignocellulosic biomass feedstocks and converted into various high-value chemicals, liquid fuels, and functional materials through a variety of pathways, which is crucial for alleviating the global fossil resource crisis and achieving carbon peaking and carbon neutrality goals. Carbon dots (CDs) are a new type of zero-dimensional carbon-based nanomaterials with particle size usually less than 10 nm, whose core is usually composed of sp2 hybridized carbon, and whose surface contains abundant functional groups such as hydroxyl, amino, and carboxyl groups, which have excellent UV-visible absorption, strong proton adsorption, and good stability and hydrophilicity. The high electron-transferring property of the surface functional groups of CDs makes them excellent electron carriers and donors, especially under UV light irradiation. Especially under the irradiation of ultraviolet light, CDs can be used as a reducing agent and stabilizer to reduce metal ions to metal monomers. Zeolite molecular sieves can effectively promote the diffusion of reactants and products in the pores and improve the catalytic activity due to their highly ordered pores, large specific surface area, suitable pore size and good hydrothermal stability. Therefore, molecular sieves can be a good choice of carrier in multiphase catalysis, and their unique domain-limited environment can provide spatial confinement for metal particles to improve the resistance of metals to sintering and prevent the leaching of active metal substances during the catalytic process. Based on this, in this paper, bimetallic PdAg/CDs-ZSM-5 catalysts were prepared by reduction with zeolite molecular sieve ZSM-5 as the carrier and CDs as the reducing and stabilizing agents via UV irradiation and applied to the aqueous-phase hydrogenation-rearrangement of FFA for the preparation of cyclopentanone (CPO) reaction. The CDs and composite catalysts were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and pyridine infrared (Py-FTIR). The results showed that the CDs had good reducibility and abundant Lewis acidic sites, and were able to reduce Pd2+ and Ag+ to metal monomers and form PdAg nano-alloy structures. The effects of reaction temperature, reaction time and hydrogen pressure on the reaction performance of the aqueous-phase selective hydrogenation-rearrangement of FFA to produce CPO were investigated using PdAg/CDs-ZSM-5 as catalyst. It was shown that the synergistic effect between the suitable acidic sites on the composite catalyst and the PdAg alloy greatly promoted the rearrangement of the reaction intermediate FAL, thus selectively controlling the hydrogenation of FFA to produce FAL first and then further rearrangement to obtain CPO. 100% conversion of FFA was achieved at the reaction temperature of 160 ℃, 2 MPa H2, and the target product CPO under the reaction conditions of 4 h. The selectivity of the target product CPO was 92.6%. After reusing the catalyst for 5 times, the conversion of FFA was basically unchanged, and the selectivity of CPO only decreased by 3.6%.
Refined Ni, Co-induced synthesis of NiCoP nanoparticles uniformly embedded in NCNTs: A robust dual-functional electrocatalyst for water splitting
ZHANG Xupeng, WANG Ying, LIU Qun, ZHANG Yu, CHEN Li, ZHAN Junling, WANG Jiabo
 doi: 10.1016/S1872-5813(24)60446-9
Abstract(84) HTML(23) PDF 11739KB(11)
Abstract:
Ni, Co-induced highly distributed NiCoP nanoparticles embedded nitrogen-doped carbon nanotubes (NCNTs) (NiCo/NiCoP-NCNTs) were directly synthesized by a one-step phosphorization and carbonization process. As a bifunctional electrocatalyst for water splitting, NiCo/NiCoP NCNTs show impressive catalytic performance with an overpotential of only 206 mV for the hydrogen evolution reaction and 360 mV for the oxygen evolution reaction in 0.5 mol/L H2SO4 and 1 mol/L KOH solutions, respectively. In addition, NiCo/NiCoP NCNTs maintain a stable cell voltage of 1.68 V at 10 mA/cm2 with only a 10% decrease in current density over 48 h, showing remarkable stability. The improved catalytic activity can be attributed to the integration of NiCoP nanoparticles and the synergies between NCNTs and NiCo alloy. Additionally, the improved electrocatalytic performance can be attributed to the increased electrochemically active surface area and the reduced electron transfer resistance of the NiCo/NiCoP-NCNTs. Overall, the NiCo/NiCoP-NCNTs demonstrated significant performance for advanced water electrolysis applications.
A research paper
The effect of hydrothermal pretreatment on the catalytic performance of Zn/HZSM-5 catalysts for ethylene aromatization reaction
SHAO Jiabei, LI Baichao, DONG Mei, FAN Weibin, QIN Zhangfeng, WANG Jianguo
 doi: 10.1016/S1872-5813(24)60448-2
Abstract(76) HTML(27) PDF 1171KB(4)
Abstract:
To address the issue of coking and deactivation of Zn/HZSM-5 catalysts used for light olefins aromatization, a high-temperature hydrothermal method was employed for catalyst pretreatment. The catalysts were characterized using XRD, N2 physical adsorption-desorption, NH3-TPD, Py-FTIR, XPS and TG techniques. The effect of high-temperature hydrothermal pretreatment on the catalytic performance and stability of the catalyst was investigated using ethylene aromatization as a probe reaction. The results showed that the Zn/HZSM-5 catalyst exhibited excellent catalytic performance after 48 h of high-temperature hydrothermal pretreatment. Although the conversion of ethylene slightly decreased, the catalyst lifetime was significantly extended, increasing from 72 to 216 h, while the aromatics selectivity remained above 60%. It was suggested that the hydrothermal treatment enhanced the interaction between ZnO species and Brønsted acid sites, promoting the generation of ZnOH+ species. This not only suppressed the hydrogen transfer reaction but also significantly enhanced the dehydrogenation performance of the catalyst, improving the selectivity towards hydrogen. Additionally, the catalyst exhibited increased carbon capacity and reduced carbon deposition rate after hydrothermal treatment, demonstrating excellent anti-coking properties.
A research paper
Effect of the metal-support interaction in the Cu/ZnO catalyst on its performance in the hydrogenation of furfural to furfuryl alcohol
YU Xinrui, ZHANG Jinyu, YANG Haixing, CHONG Siying, LIU Guoguo, ZHANG Yajing, WANG Kangjun
 doi: 10.1016/S1872-5813(24)60445-7
Abstract(107) HTML(39) PDF 11658KB(4)
Abstract:
A series of Cu/ZnO catalysts were prepared by the coprecipitation method and the effect of Cu/Zn ratio on the strong metal support interaction (SMSI) as well as its relation to the catalytic performance of Cu/ZnO in the gaseous hydrogenation of furfural to furfuryl alcohol was investigated. The H2-TPR, XRD, SEM, TEM and XPS characterization results reveal that there exists the SMSI effect in the Cu/ZnO catalyst that influences the catalyst microstructure. ZnO support, acting as a geometric modifier on the active metal Cu particles, has a significant influence on the electronic state of the surface Cu species. The strength of SMSI is related to the Cu/Zn ratio and the SMSI strength of various Cu/ZnO catalysts follows the order of 20Cu/ZnO > 40Cu/ZnO > 60Cu/ZnO > 80Cu/ZnO. Under the same reaction conditions, the lifetime of the 20Cu/ZnO catalyst with a furfural conversion of above 80% is only 5 h, in comparison with the lifetime of 28 h for the 60Cu/ZnO catalyst. That is, appropriate SMSI can enhance the stability of the Cu/ZnO catalyst in the hydrogenation of furfural to furfuryl alcohol, whereas excessive SMSI is detrimental to the catalyst activity.
Theoretical calculations of pyridine adsorption on the surfaces of Ti, Zr, N doped graphene
WANG Jucai, TANG Ke, SUN Xiaodi, HONG Xin
 doi: 10.1016/S1872-5813(24)60440-8
Abstract(102) HTML(35) PDF 6337KB(8)
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In this paper, the adsorption behavior of pyridine, a typical basic nitrogen compound in diesel oil, on Ti-doped, Zr-doped, N-doped and intrinsic graphene has been investigated by density functional methods. The corresponding adsorption energy, adsorption configurations, Mulliken charge transfer, differential charge density and density of states were discussed. The results show that doping graphene with metal atoms such as Ti or Zr can significantly obviously enhance the adsorption energy between pyridine and graphene surfaces, while non-metal N doping has a relatively minor effect. The magnitude of the adsorption energy of pyridine on the surfaces of graphene modified with different atoms follows the order: Ti-doped>Zr-doped>N-doped>intrinsic graphene, Pyridine interacts with Ti- or Zr-doped graphene through N−Ti, N−Zr and π−π interactions, while with N-doped and intrinsic graphene, it interacts via N−N, C−N and π−π interactions. There are significantelectron transfer and chemical bond formation between pyridine and metal-doped (Ti, Zr) graphene surfaces, indicating chemical adsorption. However, there is no chemical bond formation with non-metal N-doped graphene and intrinsic graphene, suggesting physical adsorption in these cases. Overall, pyridine exhibits more stable adsorption on the surfaces of Ti, Zr-doped graphene.
The promotional effects of ZrO2 modification on the activity and selectivity of Co/SiC catalysts for Fischer-Tropsch synthesis
WANG Min, GUO Shupeng, XU Jinshan, LI Liuzhong, CHEN Congbiao, MA Zhongyi, JIA Litao, HOU Bo, LI Debao
 doi: 10.1016/S1872-5813(24)60439-1
Abstract(52) HTML(30) PDF 686KB(2)
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Co/SiC catalysts have exhibited excellent performance in Fischer-Tropsch synthesis reaction. However, few research focuses on investigating the effect of SiC supports surface properties of on catalyst performance. In this study, ZrO2 was utilized to modify the SiC surface, leading to the preparation of a series of Co-ZrO2/SiC catalysts. The physicochemical properties of the catalyst were comprehensively analyzed by using N2 adsorption, XRD, H2-TPR, XPS analyses. Catalytic performance was evaluated using a fixed bed reactor, shedding light on the effect of ZrO2 modified SiC support on cobalt-based Fischer-Tropsch synthesis catalysts. The results indicated that ZrO2 surface modification on SiC resulted in an enhanced reduction degree of Co/SiC catalysts. Additionally, ZrO2 exhibited strong interaction with the amorphous phase on the SiC surface, thereby weakening the interaction between Co and the amorphous phase. This led to an increase in the electron density of cobalt species, consequently improving the selectivity of Co/SiC catalysts towards long-chain hydrocarbons.
Promoted stability of Cu/ZnO/Al2O3 catalysts for methanol production from CO2 hydrogenation by La modification
NIU Mengmeng, JIANG Yanan, ZHANG Xian, ZHANG Cuijuan, LIU Yuan
 doi: 10.1016/S1872-5813(24)60438-X
Abstract(99) HTML(59) PDF 3064KB(27)
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Deactivation of Cu/ZnO/Al2O3 catalysts in CO2 hydrogenation to methanol reaction is one of the main reasons limiting their application. We synthesized a series of La modified Cu/ZnO/Al2O3 catalysts by adding different contents of La to improve the stability. In the 100 h short-term stability test at 200 ℃ under 3 MPa with a GHSV of 12000 mL/(g·h) , the unmodified Cu/ZnO/Al2O3 catalysts degraded obviously over 100 h. In sharp contrast, the stability was significantly promoted by the addition of La. The best activity was achieved with 5% La added samples (4% CO2 conversion and 85% methanol selectivity),which also showed impressive stability over 1000 h except about 17% deactivation during the initial 190−220 h. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results revealed that the addition of 5% La improved the dispersion of Cu and Zn, inhibited the sintering of Cu, stabilized the Cu0/+ species and retarded oxidation of Cu in catalysts, which attributed to the high stability of the catalysts.
Preparation of Ni0.6Cu0.4O/NC catalyst and its catalytic performance for hydrogen production from hydrolysis of ammonia borane
LI Rong, ZUO Youhua, HUA Junfeng, HAO Siyu, XU Lixin, YE Mingfu, WAN Chao
 doi: 10.1016/S1872-5813(24)60436-6
Abstract(71) HTML(28) PDF 2338KB(9)
Abstract:
Ammonia borane (NH3BH3, AB) is an ideal feedstock with high hydrogen storage capacity. In this paper, nitrogen-containing carbon material (Ni0.6Cu0.4O/NC) catalyst was prepared by high-temperature carbonization of Ni/Cu-ZIF precursor under nitrogen atmosphere. The microstructure as well as the composition of the as-prepared catalyst were characterized. In addition, the catalytic performance of the catalyst were tested under reaction conditions. The results showed that the activation energy (E a ) for hydrolysis of AB over Ni0.6Cu0.4O/NC catalyst was 56.8 kJ/mol with TOF value as high as 1572.2 h−1. The hydrogen production could be approximated as a zero-order reaction with respect to the concentration of AB, and a one-order reaction with respect to the amount of catalyst. The catalyst still maintained good activity after ten cycles, indicating the good stability.
CO2 assistant oxidative dehydrogenation of isobutane to isobutene catalyzed by zncazr solid solution
LIU Yupeng, LIU Lingji, YU Xiaosheng, WANG Yongzhao, LI Guoqiang, LI Lei, WANG Changzhen
 doi: 10.19906/j.cnki.JFCT.2024003
Abstract(157) HTML(77) PDF 8635KB(48)
Abstract:
CO2-assisted oxidative dehydrogenation of isobutane to isobutene (CO2-BDH) is an environmentally friendly low-carbon dehydrogenation process, which can effectively utilize greenhouse gas CO2 while producing value-added product isobutylene. Besides, the soft oxidizing property of CO2 can break the thermodynamic limitation of dehydrogenation reaction and avoid the problem of deep oxidation, which makes isobutylene highly selective. However, its industrialization is still challenged by the lack of green and efficient catalysts. In this work, xZn-CaZr solid solution catalysts was prepared by one-pot co-precipitation method and applied to CO2-BDH reaction. The physicochemical properties of all catalysts were investigated by various means, and the structure-activity relationship and surface redox mechanism were described in combination with catalytic performance. The results show that xZn-CaZr catalysts formed solid solution structure with Zn species (6%−12%) existing in highly dispersion state, and the "confinement effect" given by mesoporous skeleton and strong metal-support interactions contributes to the stable distribution of nanoscale sites and generates more Zn-O-Zr interfaces. When excessive Zn species (16%) is added, the ZnO crystal will have obvious phase separation from the solid solution phase. The surface chemical states of different catalysts were analyzed by XPS, and it was found that the relative content of Oβ increased first and then decreased with the increase of Zn content. In addition, the surface reduction characteristics of the catalyst indicated that the promotion of an appropriate amount of Zn species can improve the mobility of lattice oxygen, thus 0.4Zn-CaZr catalyst showing the highest relative content of Oβ and the best oxygen conductivity. In the activity evaluation of different xZn-CaZr catalyst, 0.4Zn-CaZr catalyst shows the best catalytic dehydrogenation activity but its stability is poor, while 0.2Zn-CaZr catalyst has the best reaction stability. Moreover, the catalytic performance of ZnCaZr catalyst under different C4H10-CO2 ratios was also investigated, which indicated that the higher CO2 content in the feed gas was helpful to improve the catalytic stability and isobutene selectivity. Combined with the surface chemical state and carbon deposition information of the spent catalyst, it was found that the relative content of Oβ on the surface of 0.4Zn-CaZr catalyst decreases obviously, but the carbon deposition rate was slow. On the contrary, the relative content of Oβ for 0.2Zn-CaZr catalyst decreased less, but its carbon deposition rate was faster. We believe that the amount and mobility of lattice oxygen over xZn-CaZr catalysts were revealed as key factors in determining the catalytic performance. Notably, higher content and superior mobility of lattice oxygen can enhance the redox function of the solid solution catalyst itself and improve the activation performance of CO2. The strong oxygen supply capacity can ensure the continuous MvK catalytic cycle on the Zn-O-Zr interface, and avoid the deep accumulation of inert carbon deposits while improving the dehydrogenation activity of isobutane and selectivity of isobutene. This study shed lights on the further design and development of green and efficient CO2-BDH catalysts.
Study on the impact of using decarbonized gasification slag for CO2 mineralization and storage to prepare calcium carbonate
LI Xiangyu, LI Xu, FAN Panpan, BAO Weiren, CHANG Liping, WANG Jiancheng
 doi: 10.19906/j.cnki.JFCT.2024008
Abstract(86) HTML(37) PDF 6063KB(16)
Abstract:
The gasification slag after carbon separation is difficult to realize effective utilization because of its high content of water and the presence of a small amount of residual carbon. To address these problems, a mineralization based on indirect carbonation to sequester CO2 and recycle calcium extraction to prepare nano-calcium carbonate process is proposed. The gasification slag after carbon separation mainly consists of CaO, Al2O3, Fe2O3, MgO, as well as some non-metallic components such as SiO2. Most of the metal components exist in amorphous form. After preliminary screening of acidic leaching agents, it was found that hydrochloric acid can effectively destroy the structure of gasification slag and dissolve the metal components in gasification slag. In this paper, the effects of leaching agent type, concentration, reaction time, temperature and liquid-solid ratio on the leaching rate of calcium from decarbonized gasification slag were investigated in detail. The results showed that the highest calcium leaching rate of 98.79% was achieved under the leaching conditions of 2 mol/L HCl, liquid-to-solid ratio of 20 mL/g, reaction temperature of 50 ℃ and reaction time of 90 min. Meanwhile, the effects of CO2 flow, temperature and time on the carbonation efficiency and precipitated calcium carbonate (PCC) crystal structure were investigated. In the carbonation stage, the main factor affecting carbonation efficiency is CO2 flow. This is because excessive CO2 will cause carbonic acid to form in the solution and partially dissolve the precipitated CaCO3, resulting in a sharp decrease in carbonation efficiency. And the carbonation efficiency gradually increases with the increase of reaction temperature. Generally speaking, increasing the temperature is beneficial for chemical reactions. However, owing to the exothermic nature of the carbonation reaction, the positive promotion effect of high temperature on the reaction process is weakened, and the solubility of CO2 in water is reduced, resulting in a slow decrease in carbonation efficiency. The effect of reaction time on carbonation process has the same trend as the change in reaction temperature. The highest carbonation efficiency could reach 99.59% by optimizing the carbonation reaction conditions. In addition, the reaction temperature and time significantly affected the calcium carbonate crystal structure and micromorphology. The formation of calcium carbonate crystals mainly goes through three stages. In the first stage, as the reaction time prolongs, disordered amorphous calcium carbonate rapidly dehydrates to form ordered calcium carbonate crystal structure. At high supersaturation, vaterite begins to nucleate and undergoes spherical growth through nucleation at the growth front. Gradually, the solubility of amorphous calcium carbonate gradually decreases, and vaterite continues to grow into polycrystalline spheres composed of roughly equal sized crystals. In the second stage, vaterite is formed under equilibrium conditions, and its crystal size almost no longer increases, leaving part of the remaining amorphous calcium carbonate dissolution and crystallization process. In the third stage, vaterite begins to decompose and forms calcite or aragonite through dissolution-recrystallization process. Experiments result have shown that vaterite and calcite are formed at low temperatures, and aragonite is formed when heated to a certain temperature. As the reaction time increases, the particle size of calcium carbonate gradually increases. Therefore, lowering the reaction temperature and time is more favorable to the formation of vaterite type calcium carbonate.
A research paper
Dehydration of sugar mixtures to 5-hydroxymethylfurfural catalyzed by modified tin-mordenite
ZHANG Ruonan, LI Gang, MA Zhongmin, LÜ Qiang
 doi: 10.19906/j.cnki.JFCT.2024018
Abstract(94) HTML(47) PDF 1106KB(11)
Abstract:
5-hydroxymethylfurfural (HMF) is a versatile compound that has great market potential in the future chemical industry. HMF production from fructose has a problem of higher cost, while HMF production from glucose has a problem of lower yield. Therefore, the use of relatively inexpensive biomass-derived syrup to produce HMF in order to achieve industrial production is currently a research hotspot. A series of Sn-MOR catalysts were prepared by using mordenite zeolite (H-MOR) as a carrier, which was modified with acid treatment and adding tin to remove Al and replenish Sn. The Sn-MOR catalysts were characterized by X-ray diffraction (XRD), diffuse reflectance ultraviolet-visible spectra (UV-vis), ammonia temperature programmed desorption (NH3-TPD), and X-ray fluorescence spectroscopy (XRF). The characterization results showed that the Sn-MOR still maintained the crystal structure of mordenite, with changes in strength and content of acid centers , and Sn was inserted into the zeolite skeleton. Glucose and fructose were used as substrates in the catalytic reaction of unmodified H-MOR and modified Sn-MOR, and the experimental results showed that H-MOR catalyzed the dehydration reaction of glucose poorly, with a HMF yield of only 7.08%, but its catalytic performance in dehydration of fructose was better, with a HMF yield of 76.78%. The modified Sn-MOR possessed isomerization activity, which improved the reactivity of glucose dehydration with a HMF yield of 38.65%, while the modified Sn-MOR still maintained the high catalytic activity of MOR for fructose dehydration to HMF. Using sugar mixtures (mhydrated glucosemfructose = 1∶1) as the substrate, the reaction performance of the catalysts with different tin metal additions to H-MOR was firstly investigated, and the results showed that 3.76-Sn-MOR with 3.76% tin addition catalyzed the dehydration of the sugar mixtures better. The reaction performance of the catalyst prepared by adding tin after H-MOR acid treatment was further investigated, and the results showed that the 3.76-Sn-MOR1 prepared by acid treating H-MOR using 1 mol/L hydrochloric and adding tin could obtain better HMF yield (49.37%) and selectivity (58.09%) in dehydration of sugar mixtures. The reaction conditions were further optimized through orthogonal experiments using a 3.76-Sn-MOR1 catalyst in terms of sugar concentration, reaction temperature, catalyst dosage, and reaction time. The results showed that neither too high nor too low sugar concentration was conducive to HMF formation, and increasing temperature and catalyst dosage were conducive to HMF formation, but increasing temperature reduced the selectivity of HMF. Prolongating reaction time had little effect on improving the yield of HMF, but decreased the selectivity of HMF. The optimal reaction conditions were as follows: 1.5 g of sugar mixtures, reaction temperature of 170 ℃, catalyst dosage of 0.3 g, and reaction time of 3 h. Under the above optimal reaction conditions, the superior catalyst 3.76-Sn-MOR1 was finally applied to F55 fructose syrup, which has a dry matter ratio of glucose and fructose similar to that of sugar mixtures, and the HMF yield was 63.76%, the HMF selectivity was 69.43%, and the fructose syrup conversion was 91.82%. The catalyst was recycled five times and the HMF yield reduced to 49.50%, which still maintained a certain catalytic activity.
Role of interfacial effects in the oxidation of toluene by MnOx-modified CeO2 nanocubes
YE Peng, WU Qilong, TIAN Xi, SONG Hua, GAN Lina
 doi: 10.19906/j.cnki.JFCT.2024010
Abstract(85) HTML(47) PDF 9080KB(4)
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Toluene, a common volatile organic compounds (VOCs), can have adverse effects on the natural environment as well as on human health. Catalytic oxidation technology can remove toluene economically and efficiently, and the key to this technology is the development of efficient catalysts. In order to improve the oxidation efficiency of toluene, it is of great significance to explore and study new efficient catalysts. In this study, binary xMn/Ce (xMnOx/CeO2) catalysts with different Mn loadings were successfully prepared by a two-step hydrothermal-impregnation method, and the performance of these catalysts was evaluated in the catalytic oxidation reaction of toluene. The results showed that the introduction of MnOx significantly increased the toluene oxidation activity of the catalysts. In particular, when the Mn loading was 10% (10Mn/Ce), the t90 (temperature at which toluene conversion reached 90%) was only 233 ℃ at gas hourly space velocity of 60000 mL/(g·h), showing optimal toluene catalytic oxidation activity. This result suggests that the addition of moderate amount of MnOx can significantly improve the catalytic performance of the catalysts. By characterization means such as X-ray diffraction (XRD), Raman, transmission electron microscopy (TEM), programmed temperature-raising reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS), we found that the incorporation of MnOx creates an interfacial effect between MnOx and CeO2, which significantly alters the physicochemical properties of the Mn/Ce catalysts. Due to the interfacial effect, the concentration of Ce3+ and Mn3+ ions and the oxygen vacancy in the 10Mn/Ce catalyst were not only increased, but also the strength of Ce−O bond on the catalyst surface was reduced, which made it easier for surface lattice oxygen to participate in the catalytic oxidation of toluene, and enhanced the redox performance of the catalyst, thus promoting the catalytic oxidation of toluene. In this study, we not only successfully prepared Mn/Ce catalysts with excellent toluene oxidation activity, but also revealed the mechanism of interfacial effect behind it, which provides a simple and effective method and idea for the design and preparation of efficient oxidation catalysts for VOCs.
Research progress of chemical catalysis for biomass-based furfural to nitrogen-containing compounds
CHEN Jiayue, LI Keming, HUANG Yaobing, LU Qiang
 doi: 10.19906/j.cnki.JFCT.2024007
Abstract(132) HTML(91) PDF 927KB(22)
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The utilization of biomass holds a great promise to partially replace the non-renewable fossil resources for the production of chemicals and materials for daily use, which could effectively mitigate the challenges associated with global resource scarcity. Furfural, a prominent biomass-derived platform compound derived from the dehydration of xylose in hemicellulose, which is widely used as the key intermediate or solvent in the petrochemicals, coating, pesticides, medicine, synthetic rubber, etc. At the same time, furfural can be converted into a series of high value-added chemicals and fuel, such as alcohols, acids, esters, nitriles, amines, and others due to its active C=O bonds and furan rings. Typical chemical reactions, such as reduction, oxidation, etherification, ammonia oxidation, reduction amination, ring rearrangements and others, are frequently used for the above conversions. Among various chemicals obtained from furfural conversions, nitrogen-containing compounds have attracted considerable attention, owing to the wide applications of such type molecules in the synthesis of drug molecules, bioplastics, and other functional materials. Therefore, using furfural as a raw material to synthesize bio-based nitrogenous compounds represents a cutting-edge research direction. In the presence of nitrogen sources, furfural can be transformed into diverse nitrogen-containing compounds through different reactions, such as reduction amination, ammonia oxidation, oxidative coupling, etc. Varied nitrogen sources (e.g. NH3, N2H4·H2O, NH4HCO2, CH3COONH4, (NH4)2CO3 and others), catalysts, reaction atmospheres, and temperatures can result in distinct target products during furfural conversions. Currently, domestic and foreign research groups have made significant progress on furfural conversions to different nitrogen-containing compounds. Therefore, this review aims to briefly outline the recent achievements in the synthesis of high-value nitrogen-containing compounds from furfural through catalytic conversions over different catalysts. The main content includes: (1) synthesizing amines by reduction aminations, e.g. primary, secondary, and tertiary amines; (2) nitriles production by ammonia oxidation; (3) producing amides by amidation; (4) preparing heterocyclic compounds, such as benzoheterocyclic, thiazole, pyrrole, indole, piperidine and pyridine via oxidative cyclization, decarbonylation-amination, reduction amination, hydrogenation, ring rearrangements. The influences of synthesis methods, catalyst types, reaction pathways, mechanisms, as well as the nitrogen sources, on product distributions were discussed in detail. Considering the pathways and products potentially affected by different nitrogen sources and reaction conditions, future breakthroughs in the synthesis of nitrogen-containing compounds from furfural can be anticipated from the following aspects: (1) By systematically considering the reaction processes and mechanisms, the construction of composite catalysts and precise adjustment of reaction conditions to integrate multiple reaction steps into one is a trend in this research area to attain more efficient and green conversion processes; (2) Combined experimental with theoretical investigations to comprehensively reveal the reaction pathways during the reaction of different nitrogen sources with furfural; (3) Exploration of new chemical conversion routes and catalysts for the production of more novel nitrogen-containing compounds, to further broaden the application areas of furfural based chemicals. In brief, this review provides a systematical review on the production of furfural based nitrogen-containing chemicals, which would benefit the communities working in biomass utilization areas, and also contribute to the establishment of knowledge of the furfural chemical family.
Study on the enhancement mechanism of low-temperature SCR performance of ammonium persulfate coupled transition metal oxides modified carbon-based catalysts
XIAO Ling, HUANG Yan, QIAO Shufang, ZHAO Lingkui, LI Simi
 doi: 10.19906/j.cnki.JFCT.2024006
Abstract(65) HTML(55) PDF 2843KB(2)
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In recent years, carbon-based catalysts have received extensive attention in the field of NH3-SCR due to their unique advantages. In order to improve the performance of low-temperature NH3-SCR of carbon-based catalysts, V/OAC, Fe/OAC, Mn/OAC and Cu/OAC carbon-based catalysts were prepared by oxidizing and coupling transition metal oxides with ammonium persulfate. The mechanism of SCR performance enhancement of modified carbon-based catalysts was investigated by means of catalytic activity test, Physical adsorption, FT-IR, XPS, NH3-TPD, H2-TPR, EPR and other characterization methods. The results show that ammonium persulfate oxidation can introduce a large number of acidic oxygen-containing functional groups to the surface of activated carbon support, promote the formation of oxygen vacancy in transition metal oxides, and improve the surface acidity and redox performance of carbon-based catalysts, therefore the low temperature NH3-SCR performance of the carbon-based catalyst was improved. In particular, we found that oxidation of ammonium persulfate can induce the formation of lower valence states of transition metal elements (V, Fe, Mn, Cu ). Therefore, after oxidative modification of ammonium persulfate, the performance of V/OAC and Fe/OAC catalysts with low-priced metals in active components conducive to NH3-SCR reaction is significantly improved, the NO conversion of VOx/OAC and FeOx/OAC catalysts at 100 ℃ increased from 18.2% to 34.8% and from 34.2% to 55.6%, respectively; while the performance of Mn/OAC and Cu/OAC catalysts with high-priced metals in active components conducive to NH3-SCR reaction is limited, the conversion of NO at 100 ℃ only increased from 61.4% to 70.4% and from 61.3% to 69.7%. This work summarized the regulatory effect of ammonium persulfate oxidation modification on the surface metal states of carbon-based catalysts, which is helpful to deeply understand the regulation law of physical and chemical properties of carbon-based catalysts by oxidative modification of ammonium persulfate, and provide guidance and reference for the development of high-efficiency carbon-based denitrification catalysts.
A research paper
Ethanol production from syngas over RhnNin/TiO2(n = 1, 2, 3, 4) catalysts: probing into the roles of RhnNin alloy clusters size in tuning catalytic performance
ZHANG Jingjing, LING Lixia, MA Caiping, ZHANG Riguang, WANG Baojun
 doi: 10.1016/S1872-5813(24)60454-8
Abstract(97) HTML(40) PDF 24813KB(7)
Abstract:
The direct production of ethanol from syngas on RhnNin/TiO2 (n = 1, 2, 3, 4) has been investigated by using density functional theory (DFT) and micro-kinetic methods, in order to elucidate the regulatory mechanism of RhnNin alloy cluster size-induced metal-support interactions on the performance of ethanol synthesis. The results showed that Rh1Ni1/TiO2 and Rh3Ni3/TiO2 can significantly enhance the CO conversion and C−C chain formation, while inhibiting the methane generation. Among them, Rh1Ni1/TiO2 exhibits the highest ethanol generation activity and relative selectivity. Electronic property analyses revealed that Ni atoms on the alloy clusters and Ti and O atoms on the supports transferred the most of charge to the Rh atoms on the Rh1Ni1/TiO2 catalysts. The Rh-Ni interactions on the alloy clusters were the strongest, and the alloy clusters exhibited the strongest interactions with the TiO2 supports, resulting in the highest catalytic activity among the catalysts. Ab-initio molecular dynamics (AIMD) simulations at 525 K showed that the Rh1Ni1/TiO2 catalyst exhibited high thermal stability.
A research paper
Combination of modified molybdenum sulfide catalyst and non-thermal plasma for syngas production from H2S-CO2 acid gas
FENG Wenshuang, YUWEN Xiaomeng, MU Xiaoliang, ZHAO Lu, FANG Kegong
 doi: 10.19906/j.cnki.JFCT.2024026
Abstract(45) HTML(24) PDF 4947KB(7)
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The petrochemical, natural gas, and coal chemical industries will produce a large number of hydrogen sulfide (H2S) and carbon dioxide (CO2) mixed acid gas, causing serious damage to the environment and human health. At present, the most widely used treatment technology for H2S-containing mixed acid gas is the Claus process. Nevertheless, the Claus process is unable to achieve the recovery of hydrogen sources and the reduction of CO2 emissions, resulting in a considerable quantity of CO2 being discharged directly into the atmosphere, which has a detrimental impact on the global climate. Carbon, hydrogen, sulfur and other elements play an important role in the field of energy. Therefore, it is of great importance to explore new methods for the utilization of H2S and CO2 mixed acid gas to save energy, protect the environment and achieve green and low-carbon development. A non-thermal plasma-catalysis method is used to convert H2S and CO2 acid gas into syngas in a single step. This method achieves both the clean treatment of waste gas and its resource utilization, making it a novel route for syngas preparation. The non-thermal plasma contains high-energy electrons that can transfer energy to H2S and CO2 molecules in the form of inelastic collisions, thereby exciting them into free radicals, ions, excited molecules and atoms. Concurrently, the catalyst filled in the discharge gap can facilitate the chemical reactions of these active species. However, the stable molecular structure of H2S and CO2 presents a significant challenge to the improvement of energy efficiency, particularly in the context of high conversions of reactive molecule. The development of efficient catalysts is crucial to improve the H2S and CO2 conversion. The existing results demonstrate that electrons, photons and strong electric field generated by non-thermal plasma can be used to excite MoS2 catalyst to generate highly active electron-hole pairs. These in turn catalyze the conversion of H2S and CO2. This study used copper and zinc as promoters to modify the molybdenum sulfide catalyst, and the catalytic performance for the conversion of H2S-CO2 to syngas was effectively improved. A detailed comparison was made between the effects of the two promoters on the structure, composition, morphology, valence state, and other physicochemical characteristics of the molybdenum sulfide catalyst using various characterization methods. Furthermore, the influence factors of two types of promoters on the catalytic H2S-CO2 conversion was investigated by controlling the discharge conditions. The introduction of copper and zinc promoters was found to result in a reduction in the particle size of the molybdenum sulfide active phase, accompanied by a high degree of dispersion, which in turn led to an increase in the number of active sites. Concurrently, the adsorption strength of H2S and CO2 molecules was enhanced, which was conducive to the adsorption and activation of H2S and CO2. It revealed the structure-activity relationship between the modified molybdenum sulfide catalyst and plasma synergistic reaction. In addition, the theoretical research has enriched and expanded the theory of non-thermal plasma-catalysis. It has also provided a reference for the synthesis of modified molybdenum sulfide materials.
A research paper
Mechanism of Methanol Synthesis from CO2 Hydrogenation over Rh16/In2O3 Catalysts: A Combined Study on Density Functional Theory and Microkinetic Modeling
WANG Yuning, GONG Jiesong, ZHOU Jiabin, CHEN Zhiyuan, TIAN Dong, NA Wei, GAO Wengui
 doi: 10.1016/S1872-5813(24)60460-3
Abstract(45) HTML(31) PDF 20365KB(7)
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In this investigation, the hydrogenation of carbon dioxide (CO2) to methanol (CH3OH) over a Rh16/In2O3 catalyst is meticulously analyzed through the application of Density Functional Theory (DFT) and microdynamics modeling. The research focuses on the spontaneous dissociation mechanisms of H2 and CO2 at the Rh16/In2O3 interface, with a special emphasis on the role of oxygen vacancies in In2O3 which enhance adsorption processes. Bader charge analysis revealed a marginal positive charge on Rh16, elucidating critical insights into the electronic characteristics and catalytic activity of the system. The study establishes the RWGS+CO-Hydro pathway as the predominant mechanism for methanol synthesis, characterized by a sequential transformation of intermediates: CO2*→COOH*→CO*+OH*→HCO*→CH2O*→CH2OH*→ CH3OH*. Further, Degree of Reaction Rate Control (DRC) analysis conducted across a range of temperatures (373−873K) and pressures (10−2−103 bar) identified two principal kinetic phenomena: at lower temperatures coupled with higher pressures, the conversion of CO* + H* to HCO* significantly impacts the overall rate of reaction; conversely, at higher temperatures, the step from CH2O* + H* to CH3O* is found to dominate.
A research paper
Cr-MIL-101 derived nano-Cr2O3 for highly efficient dehydrogenation of n-hexane
LI Xiuyi, SHEN Haowei, XU Jiale, LI Chunyi
 doi: 10.1016/S1872-5813(24)60458-5
Abstract(44) HTML(42) PDF 4260KB(4)
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Nano-Cr2O3 (n-Cr2O3) was prepared by calcining the mesoporous Cr-MIL-101, and the catalytic performance for n-hexane dehydrogenation was investigated. It was found that dehydrogenation of n-hexane on n-Cr2O3 can produce n-hexenes and benzene efficiently, and the catalytic performance is related to the calcination temperature. The optimal n-hexane conversion can be obtained on n-Cr2O3-600, is 40.6%, and the selectivities to n-hexenes and benzene are 20.1% and 69.3%, respectively. Increasing the calcination temperature, the conversion of n-hexane is decreased while the stability is enhanced. The n-hexane conversion of p-Cr2O3-1 (obtained by precipitation method) and p-Cr2O3-2 (obtained by calcinating Cr(NO3)·9H2O directly) catalysts are relative low (<7.5%), and their specific activity for n-hexane dehydrogenation are 1.5 and 1.7 g/(m2·h), respectively, lower than that of n-Cr2O3-600 (2.0 g/(m2·h)). The results of BET、XRD、TEM and FT-IR reveal that n-Cr2O3 is the nanoparticle with large specific surface area that more crystal planes and dehydrogenation active sites are exposed, while p-Cr2O3 is the large particle with extremely low surface area that the dehydrogenation active sites are less exposed. By contrast, industrial Cr2O3/Al2O3 catalyst possesses high specific activity of 2.4 g/(m2·h) due to the dispersion effect of Al2O3. Therefore, the highly catalytic activity of n-Cr2O3 for n-hexane dehydrogenation is attributed to the unique properties of n-Cr2O3: small particle, large specific surface area and more exposed active sites. This work not only explains the highly dehydrogenation performance of nano-Cr2O3 derived by Cr-MIL-101, but also provides guidance for the precise design and synthesis of high-performance CrOx-based catalyst for the dehydrogenation of alkanes.
A research paper
Influence of Al2O3 precursors on Cu/ZnO/Al2O3 catalysts for hydrogen production from steam reforming of methanol
HUANG Min, BO Qifei, LI Juan, QIAO Jingxuan, YUAN Shanliang, ZHANG Biao, CHEN Honglin, JIANG Yi
 doi: 10.1016/S1872-5813(24)60459-7
Abstract(50) HTML(28) PDF 7622KB(5)
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This research outlines the synthesis of a variety of Cu/ZnO/Al2O3 catalysts utilizing the co-precipitation method, emphasizing an investigation into the impact of various Al2O3 precursors on the catalyst's structure through thorough structural characterization techniques. Furthermore, the catalytic performance of these materials in methanol reforming for hydrogen production was systematically evaluated. The results showed that the simultaneous co-precipitation of Al3+ with Cu2+ and Zn2+ resulted in the partial substitution of Cu2+-Zn2+ in alkali carbonates by Al3+, forming a hydrotalcite-like structure and strengthening the Zn-Al interactions. By contrary, after the coprecipitation of Cu2+ and Zn2+ was completed, the adverse effect of Al3+ on Cu-Zn substitution in alkali carbonates was effectively attenuated by the introduction of the Al2O3 precursor. This promoted Cu-ZnO interaction, facilitated the dispersion of CuO species, catalyst reduction, and further improved the Cu dispersion on the surface, ultimately leading to the improvement of catalytic activity. Notably, the catalyst prepared with pseudo-boehmite as Al2O3 precursor showed the highest activity. Under the conditions of H2O/CH3OH molar ratio of 1.2 and reaction temperature of 493 K, the methanol conversion reached 94.8% and the H2 space-time yield was 97.5 mol/(kg·h). Moreover, its catalytic activity remained relatively stable during a continuous operation for 25 h. Even heat treated at 723 K for 10 h, the activity loss of the catalyst was only 5.37%.
A research paper
Theoretical study on the catalysis mechanism of sulfur-doped carbon nanotubes in CO2 desorption from monoethanolamine solution
REN Yingying, LIU Junlong, CHENG Huaigang, GAO Yangyan
 doi: 10.19906/j.cnki.JFCT.2024030
Abstract(73) HTML(29) PDF 6832KB(13)
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The CO2 absorption by alkanolamine solution has been applied industrially because of its excellent efficiency. However, the energy consumption for CO2 desorption is high. To reduce the energy consumption, the catalyst is introduced into the alkanolamine capture system. In this study, the catalysis mechanism of sulfur-doped carbon nanotubes (S-CNTs) in CO2 desorption from monoethanolamine (MEA) solution is explored by simulation based on density-functional theory (DFT) calculations. It was found that compared with the single wall carbon nanotubes (CNTs), the adsorption performance of the key substances in the absorption-desorption process on S-CNTs was different, and the adsorption energy of the reactant MEA was reduced by 1.50 kcal/mol, and the adsorption energy of the absorption intermediates MEACOO-_MEAH+ was increased by 2.32 kcal/mol, and the adsorption energy of the absorption product carbamate (MEACOO-)increased significantly. By transition state searching, energy barrier for the rate-determining step was reduced by 1.15 kcal/mol in the desorption process with S-CNTs as the catalyst, suggesting that S-CNTs contributes to amine regeneration. By observing the Mulliken charge of C atoms in the vicinity of S atoms, it was found that the charge of C atoms changed from electroneutral (0.001 eV) to electronegative (−0.325 eV) . The partial density of states (PDOS) of C, N and O atoms from the absorption intermediate MEA+COO and the absorption product MEACOO-MEAH+ changes greatly when they adsorbed on CNTs and S-CNTs. In addition, compared with CNTs, the charge density on S-CNTs increases, and the C atoms near the doped S atoms attain obvious electronegativity. Compared with CNTs, the absorption intermediate MEA+COO and the absorption product MEACOO-MEAH+ transfer more charges to S-CNTs. This paper is of guiding significance for protecting the environment, maintaining the sustainable development of the energy industry, improving the utilisation rate of raw materials, and reducing the production cost of desorbed CO2. It aims to provide some theoretical basis for the design of catalysts through the study of the catalysis mechanism of S-CNTs in CO2 desorption from monoethanolamine solution.
A research paper
Study of pre-coking modified ZSM-5 molecular sieve and its benzene and syngas alkylation properties
LIU Xiuquan, ZHAO Zhitong, TANG Mingxing, XU Hong, DAI Pu, GE Hui, LI Xuekuan
 doi: 10.19906/j.cnki.JFCT.2024023
Abstract(95) HTML(29) PDF 6351KB(14)
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Toluene, xylene and other alkylbenzenes are important basic chemical raw materials, which mainly come from the petrochemical industry. With the increasing foreign dependence of petroleum resources in China, the development of coal-to-aromatics technology can not only alleviate the problem of shortage of petroleum resources in China, but also promote the transformation and upgrading of consumption in the traditional coal chemical industry and promote the clean and efficient use of coal. In this paper, methanol-modified ZSM-5 molecular sieves were used and mechanically milled with ZnCrOx in a mass ratio of 3∶1 as a composite catalyst, so as to investigate the catalytic effect of pre-preg carbon modified ZSM-5 molecular sieves. Under the reaction conditions of 450 ℃ and 4.0 MPa, the catalytic performance of the catalyst modified with pre-built carbon for 24 h was the best, in which the conversion of benzene reached 20.18% and that of CO reached 46.55%. It was found that the catalytic performance of the pre-built carbon modified ZSM-5 sieve was mainly affected by the B acid/L acid ratio, and the pre-built carbon covered some B acid sites on the ZSM-5 sieve, which reduced the B acid/L acid ratio and led to an increase in the benzene conversion, while the crystalline and pore structures of the pre-built carbon modified ZSM-5 sieve did not undergo significant changes. changed significantly. In order to better understand the deactivation mechanism of the carbon-modified ZSM-5 catalyst, TG-MS, Raman and GC-MS were used to further analyze the carbon species, and it was found that the carbon species of the carbon-modified ZSM-5 molecular sieves were mainly low-temperature carbon, which was mainly due to the fact that the strong acid was partially covered by the carbon-modified composite catalyst with the reduced amount of acid, and the carbon species were alkanes, olefins, aromatics and other oligomers mainly. Soluble carbon, high-temperature carbon and graphitic carbon are less, so as to avoid the reduction of catalyst activity caused by excessive carbonisation, while the carbon species on the composite catalyst after the reaction are mainly high-temperature carbon, which is mainly because the carbon species after the reaction of the composite catalyst are mainly large-molecule aromatic hydrocarbons and olefins, and even insoluble carbon such as graphitic carbon. In addition, the deactivation mechanism of ZSM-5 molecular sieve in the alkylation reaction of benzene and syngas was speculated based on the hydrocarbon pool mechanism: in the alkylation reaction of benzene and syngas syngas syngas firstly forms methanol in the active site of metal oxides, and then the methanol migrates in the acidic site of the molecular sieve to generate alkylbenzene with benzene, but as the reaction proceeds, the alkylbenzene will be alkylated deeply in the molecular sieve to form heavy polycyclic aromatic hydrocarbons or graphitic However, as the reaction proceeds, alkylbenzene will be deeply alkylated on the molecular sieve, forming heavy polycyclic aromatic hydrocarbons or graphite carbon, etc. Such substances are not easy to diffuse in the pores and will continuously cover the acid centre and pores of the molecular sieve, which will ultimately lead to catalyst deactivation.
A research paper
DBD plasma-assisted dry reforming of methane over Ni/SiO2
ZHENG Zhaoyu, XU Bo, ZENG Aonan, WANG Anjie, LIU Yingya, SUN Zhichao, WANG Yao
 doi: 10.19906/j.cnki.JFCT.2024022
Abstract(82) HTML(52) PDF 13013KB(4)
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Dry reforming of methane reaction(DRM) utilizes both CH4 and CO2 greenhouse gases to convert them into synthesis gas (H2 and CO), which can be further synthesized into value-added chemicals such as hydrocarbons or liquid oxygen-containing compounds. The traditional thermal method for catalyzing DRM reaction often uses Ni-based catalysts. And it requires high reaction temperature (>700 ℃). The high temperature leads to sintering and carbon deposition of Ni-based catalysts, as well as low energy efficiency, which limits the application of this reaction. Dielectric barrier discharge plasma (DBD) can synergistically drive the reaction with Ni-based catalysts at low temperature, thereby addressing the drawbacks of thermal catalysis. The key of this technology is to develop catalysts that have synergistic effects with plasma and strong resistance to carbon deposition. Therefore, this paper uses nickel phyllosilicate as precursor and H2 plasma reduction to prepare highly dispersed Ni-based catalyst, which synergistically catalyze the DRM reaction with DBD plasma. Nickel phyllosilicate was prepared by deposition-precipitation method, and Ni/SiO2-DP was obtained after calcination and reduction. Ni/SiO2-IMP was prepared by impregnation method. The prepared catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, N2-adsorption-desorption, chemisorption, Fourier transform infrared, transmission electron microscope, thermogravimetric analysis and Raman spectra. The catalytic performance for dry reforming of methane (DRM) to synthesis gas was investigated in the dielectric barrier discharge(DBD) reactor. The research results indicate that Ni/SiO2 -DP has higher catalytic activity and stability, which benefits from its smaller Ni particles size, stronger interaction between Ni and support, and stronger adsorption ability for the reactants, compared with Ni/SiO2 -IMP. The CH4 and CO2 conversions of Ni/SiO2-DP are 61.7% and 70.0%. The selectivities of H2 and CO are 86.9% and 94.3%, and H2/CO is 0.92. The CH4 and CO2 conversions of Ni/SiO2-IMP are 44.2% and 28.4%. The selectivities of H2 and CO are 62.7% and 42.4%, and H2/CO is 1.48. After stability testing, the catalysts were characterized by TG. The weight loss of Ni/SiO2- IMP is 84.45%, while the weight loss of Ni/SiO2-DP is only 34.06%. The preparation conditions of Ni/SiO2 -DP were investigated. The results show that the Ni/SiO2-DP-PR from H2 plasma reduction(PR) exhibits higher catalytic activity than the Ni/SiO2-DP-TPR from temperature programmed reduction(TPR). DBD plasma reactor contains a large number of high energy particles, including H atoms, excited state H atoms, and ionic hydrogen (H+, H2+, H3+). The reduction ability of H2 plasma is much higher than that of temperature programmed reduction. H2 plasma can fully reduce the precursor at low temperature, avoiding the aggregation of Ni particles caused by temperature programmed reduction, resulting in smaller Ni particles size in the obtained catalyst. When the deposition-precipitation time is 10 hours, the catalytic activity of the catalyst is optimal. When the deposition-precipitation time is less than 10 hours, the content of Ni in the catalyst is relatively low, resulting in low activity. When the deposition-precipitation time exceeds 10 hours, long deposition-precipitation time may lead to an increase in the crystallinity and nickel phyllosilicate particles size. As the deposition-precipitation time increases, the deposition components gradually block the pores and reduce the specific surface area of the catalyst, resulting in a decrease in the catalytic activity of the catalyst. Under optimal preparation conditions, the conversions of CH4 and CO2 are 72.5% and 78.2%. The selectivities of H2 and CO are 86.7% and 94.2%, and H2/CO is 0.89. The energy efficiency is 4.36 mmol/kJ.
A research paper
Construction of Ni/ZnCo2O4@ZnO composite metal oxide desulfurization agent and its reactive adsorption desulfurization-regeneration properties
DAI Pu, GUO Mengya, GE Hui, FAN Caimei, LI Xuekuan, LI Rui, TANG Mingxing
 doi: 10.1016/S1872-5813(24)60463-9
Abstract(63) HTML(16) PDF 4147KB(10)
Abstract:
SOx released from the combustion of sulfur compounds in fuel oil has long been a serious environmental hazard, and there is an urgent need to limit the suifur content in gasoline to about 10×10−6 by using desuifurization technology to protect the environment. Reactive adsorption desuifurization (RADS) combines the advantages of hydrodesuifurization (HDS) and adsorption desuifurization (ADS), in which Ni/ZnO desulfurization agent has excellent RADS performance. Although Ni/ZnO desulfurization agent has been applied in large scale in industry, it still has the problems of insufficient desulfurization depth and poor regeneration performance. In this paper, metal Co was introduced into ZnO by co-precipitation-impregnation method to form composite metal oxides, and the composite metal oxide desulfurization agent with different Co contents was constructed, and its desulfurization activity and regeneration performance were investigated. The results of the desulfurization experiments show that the desulfurization performance of NZCo-x desulfurization agent after the introduction of metal Co is much better than that of NZ desulfurization agent, and its desulfurization performance shows a tendency of increasing and then decreasing with the increase of the Co introduction. Among them, NZCo-3 desuifurization agent has the most excellent desuifurization performance, and its desuifurization rate can reach 100%. The optimum operating conditions for NZCo-3 desuifurization agent were reaction temperature 300 ℃, total pressure 3 MPa, WHSV 2.2 h−1, and H2/Oil (v/v) 300, under which 100% desulfurization rate could be maintained. Systematic characterisation of the structure and properties of the desuifuriser using XRD, TEM, N2 adsorption and desorption, XPS and H2-TPR confirmed that a composite metal oxide desuifuriser with Ni/ZnCo2O4@ZnO structure was obtained. The formation of ZnCo2O4 in the composite metal oxide desuifuriser promotes the reduction of particle size, enhancement of dispersion and increase of specific surface area of the desuifuriser. The smaller NiO grains facilitated the reduction of NiO to Ni, generating more active sites for desuifurization. The smaller ZnO grains were favourable for adsorption of more H2S. The XRD after the reaction showed that the formed ZnCo2O4 structure was able to adsorb the generated H2S, which acted as a suifur adsorbent and improved the suifur adsorption capacity of the desuifurization agent, thus improving the desuifurization activity of the NZCo-x desuifurization agent. Finally, the evaluation results of the cyclic desulfurization experiment with NZCo-3 desulfurization agent showed that, under the reaction conditions of reaction temperature 275 ℃, reaction pressure 3 MPa, H2/Oil (v/v) 300, and mass-air velocity of 2.2 h−1, the desulfurization rate of NZCo-3 desulfurization agent could still be maintained at more than 77% after six reaction and regeneration cycles of the agent, which is only 16.51% lower than that of the fresh NZCo-3 desulfurization agent. The desulfurization rate of fresh NZ desulfurization agent was only 10.6%, which was much lower than that of NZCo-3 desulfurization agent after 6 regeneration cycles. In conclusion, the method of improving the desulfurization and regeneration performance of Ni/ZnO desulfurization agent by constructing a composite metal oxide structure in this paper provides a new idea for further designing high-performance Ni/ZnO desulfurisation adsorbents to meet the requirements of deep desulfurisation of catalytic cracking gasoline.
A research paper
The effects of calcination temperature and dispersants on the catalytic performance of Co0.8Cu0.2/CNC for the hydrolysis of ammonia borane to hydrogen were investigated
LI Rong, ZUO Youhua, XU Licheng, HUA Junfeng, FENG Jiajia, XU Lixin, YE Mingfu, WAN Chao
 doi: 10.1016/S1872-5813(24)60462-7
Abstract(48) HTML(28) PDF 13247KB(2)
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Ammonia borane (NH3BH3, AB) is considered as an ideal hydrogen storage material for portable hydrogen production. In this paper, Co0.8Cu0.2-ZIF precursor was obtained by stirring the reactants at room temperature, and a bimetallic carbon cube (Co0.8Cu0.2/CNC) catalyst was prepared by roasting this precursor at high temperature. In addition, the microstructure as well as the composition of the catalyst was investigated using various characterization methods. The change rule of the catalyst was explored by the single-variable method. The results showed that the addition of a small amount of Cu had a stabilizing effect on the cubic morphology of the Co0.8Cu0.2/CNC catalyst. When the dispersant was CTAB and the roasting temperature was 873 K, the activation energy (Ea) for catalyzing the hydrolysis of AB to hydrogen was 50.79 kJ/mol, and the transition frequency (TOF) value was as high as 23.37 min−1. In addition, the catalyst could still catalyze the complete hydrolysis of AB to hydrogen after 25 cycles, which indicated that the catalyst had good stability performance.
A research paper
Adsorption and removal mechanism of atomic oxygen on different facets of θ-Fe3C
BAI Ya, ZHENG Yu, LI Yongfeng, LIU Jinjia
 doi: 10.19906/j.cnki.JFCT.2024024
Abstract(47) HTML(24) PDF 8870KB(3)
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The Fisher-Tropsch Synthesis (FTS) is one of the most intensively studied reactions in heterogeneous catalysis, which could convert the syngas (CO and H2) from coal, natural gas, shale gas, and biomass into gasoline, diesel, and a series of important chemical products. The process provides an effective strategy for reducing environmental pollution caused by direct coal combustion, at the meanwhile, alleviating dependence on imported petroleum. During the reaction, iron-based catalysts have attracted the attention of numerous researchers due to their unique advantages, for example, low cost, flexibility in product distribution, suitability for low H2/CO ratio syngas and large operating space. And the iron-based catalysts in FTS have achieved applications successfully in industry. Iron carbide is recognized as active phases in FTS catalyzed by iron-based catalysts, among which θ-Fe3C is one of the dominant phases. Additionally, θ-Fe3C is widely applied in fields such as biomedicine and electrochemistry. However, θ-Fe3C could be oxidized under realistic conditions, affecting the performance as magnetic materials and catalysts seriously. Considering the case above, the investigation of oxidation of iron carbide θ-Fe3C is of great significance. And exploring the adsorption, as well as removal mechanism of atomic oxygen over the iron carbide facet is helpful for understanding the oxidation process, and providing a reference for improving the stability of catalysts. In this work, we have explored the adsorption of oxygen atoms from low to high coverage on three θ-Fe3C surfaces with density functional theory. Ab initio atomistic thermodynamics was utilized to investigate the effect of experimental conditions like temperature and partial pressure of H2O. According to the calculation, it was found that the adsorption at low coverage on (110) was the strongest, followed by (001), and the adsorption on (011) was the weakest, meaning that (110) can be oxidized easily. As the number of oxygen atoms adsorbed on the surface increases, the stepwise adsorption energy increases, which is a manifestation of the repulsive effect between adsorbed oxygen atoms. The average adsorption energy for each surface increases with the increase of adsorbed oxygens, and the magnitude of increase varies due to the different local structures of each facet. The average adsorption energy on (011) has a relatively small increase, indicating that the repulsion between oxygen atoms adsorbed on this crystal plane is weak; whereas opposite on (001) and (110) facets. Atomistic thermodynamic studies showed that increasing the partial pressure of H2O or decreasing the temperature will stabilize the O adsorption, leading to surface oxidation. In addition, the highest O coverage on (110) under typical FTS conditions further proved that the facet is easily oxidized, which is consistent with the adsorption results at low coverage. Finally, the removal path of adsorbed oxygen on different facets was calculated, and the results showed that adsorbed O on (011) prefer to react with CO with energy barrier of 0.84 eV. On (001) and (110), removal in the form of H2O via OH disproportionation is more favored, but the energy barrier to form O−H bond is higher for the latter facet (1.72 vs 1.47 eV).
review
Production of high-value chemicals from starch food waste by chemical conversions
ZHANG Xuan, LI Keming, HUANG Zhihao, HUANG Yaobing, YANG Shiguan, LI Jihong, WANG Tipeng
 doi: 10.19906/j.cnki.JFCT.2024028
Abstract(131) HTML(34) PDF 2009KB(12)
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With the acceleration of industrialization and urbanization, living standards in China have risen significantly, leading to substantial changes in consumption patterns. Consequently, the scale of the catering market has expanded annually, resulting in a corresponding increase in urban kitchen waste. Kitchen waste, the primary component of municipal waste, possesses both harmful and resource-rich properties. Traditional food waste treatment methods, such as incineration, landfill, and anaerobic fermentation, are extensive in scale, however, they may also suffer from several issues, e.g. secondary environmental pollution, low resource utilization rates, limited value-added outcomes. Advanced methods and technologies for high-value utilization are under development, severely restricting the utilization of food waste. The harmless and resourceful utilization of food waste will become a new trend in the future. Starch is the main component of kitchen waste, such as flour food, rice and potatoes. Thus, the development of chemical conversion methods to convert starch-rich waste is urgent. In this paper, the characteristics, existing treatment technologies and pretreatment methods of starch food waste are systematically introduced. The composition of kitchen waste is complex, including common components such as starch, oil, protein, and fiber, as well as potential impurities like plastics and metals. To achieve high-value conversion of starch-rich food waste, it is crucial to arrange appropriate pre-sorting, pre-processing, and other pretreatment processes based on the specific characteristics of different food waste sources and subsequent conversion requirements. The resource utilization technology for starch-based food waste is primarily categorized into three types: non-biological treatment, biological treatment, and chemical treatment. These technologies convert starch food waste into various products, enabling the diversified utilization of food waste. Then, the catalytic system for the conversion different starch food wastes to chemicals such as glucose, 5-hydroxymethylfurfural (HMF), levulinic acid (ester), γ-valerolactone(GVL) and lactic acid (ester) were introduced. Researchers have made great progress by using acid catalysts to catalyze the hydrolysis of starch raw materials to produce glucose, HMF and levulinic acid. The reaction mechanism can be regarded as: H+ combines with the oxygen atom of the glycoside bond to protonate and generate conjugated acid. Then, the conjugated acid breaks the C−O bond under the attack of water molecules, and generates hydroxyl, and finally the protonated glucose removes H+ to produce glucose. Glucose can be converted into HMF through two pathways: (1) Glucose is isomerized at acid sites to produce fructose, which is then dehydrated to form HMF. (2) Glucose is directly dehydrated to produce HMF under high-temperature conditions. Levulinic acid is produced from the further hydrolysis of glucose or HMF, while levulinate and GVL could be produced through alcoholysis reaction. For lactic acid (ester) production, both acid and basic catalysts showed excellent reactivity in the conversion of starch. Starch was firstly transformed into glucose, and then further isomerized to produce fructose. Fructose underwent inverse aldol condensation reaction to produce glyceraldehyde intermediates, and further underwent the addition and isomerization reactions to produce lactic acid (ester). Finally, the existing challenges and prospects in the chemical conversion of starch food waste into high-value chemicals were outlined. Presently, chemical treatment of kitchen waste remains primarily at the laboratory research stage, featured with high costs and suboptimal economic returns. Nonetheless, chemical treatment of kitchen waste typically boasts high rates of resource recycling and entails a lengthy project industry chain.
A research paper
Corrosion behavior of co-gasification slag of furfural residue and coal on alumina-silica refractories
MA Xiaotong, WANG Zhigang, LU Hao, LIU Wei, WANG Yanxia, ZHAO Jiangshan, SUN Lingmin, YAN Jingchong, ZHUANG Shujuan, LI Huaizhu, KONG Lingxue
 doi: 10.1016/S1872-5813(24)60461-5
Abstract(33) HTML(18) PDF 4347KB(1)
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Gasifition of furfural residue with coal can realize its efficient and clean utilization. But the high alkali metal content in furfural slag is easy to cause the corrosion of gasifier refractory. Two gasification coals with different silica alumina ratio and a furfural residue were selected in the study. The effects of furfural residue additions on corrosion of silica brick, corundum brick, high alumina brick and mullite brick were investigated by using XRD, SEM-EDS and Factsage Software, and the corrosion mechanism was analyzed. With increasing furfural residue addition, the permeability of the slags to high-aluminium-bearing refractories first decreases and then increases, while the permeability on silica brick shows a slight decrease trend. Leucite (KAlSi2O6) with high-melting temperature is generated from the reaction of K2O and SiO2 in slag with Al2O3 in refractories after furfural residue is added, which hinders the infiltration of slag in refractories. Kaliophilite(KAlSiO4) of low-melting point is formed when K2O content increases, and this contributes to the infiltration of slag in refractories. The acid-base reaction between slag and silica brick is distinctly occurred, more slag reacts with SiO2 in the silicon brick, resulting in a decrease in the amount of slag infiltrating into the silicon brick as furfural residue is added. The corrosion of silica brick is mainly caused by the acid-base reaction, while the corrosion of three alumina based refractory bricks of corundum, mullite and high alumina brick is determined by slag infiltration. A linear correlation between the percolation rate and slag viscosity is established, the slag permeability increase with decreasing viscosity, resutling in stronger permeability for the high Si/Al slag with lower viscosity.
A research paper
A thermodynamic consideration on the synthesis of methane from CO, CO2, and their mixture by hydrogenation
WANG Han, GUO Shujia, QIN Zhangfeng, LI Zhikai, WANG Guofu, DONG Mei, FAN Weibin, WANG Jianguo
 doi: 10.1016/S1872-5813(24)60449-4
Abstract(110) HTML(27) PDF 1285KB(25)
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The synthesis of methane from CO and CO2 by hydrogenation is now considered as a promising route in effectively storing hydrogen energy as well as sustainably producing fuels and chemicals, while many reaction details involved in such processes, in particular for the hydrogenation of the CO and CO2 mixture, are not yet adequately understood. As a supplement to our previous works on the hydrogenation of CO and CO2 into alcohols and hydrocarbons, a thermodynamic consideration is made in this work to evaluate the potential and limit for the synthesis of methane from CO, CO2, and their mixture in particular. The results consolidate that in comparison with single CO or CO2, their mixture is probably more credible in practice for the production of methane by hydrogenation, where the overall C-based methane yield can be used as the major index to evaluate the process efficiency. The hydrogenation of CO shows a higher equilibrium yield of methane than the hydrogenation of CO2, while the overall C-based equilibrium yield of methane for the hydrogenation of the CO and CO2 mixture just lies in between and decreases almost lineally with the increase of the CO2/(CO+CO2) molar ratio in the feed, despite the great change in the equilibrium conversions of CO and CO2 with the feed composition. Nevertheless, an adequate overall C-based equilibrium yield of methane (> 85%) can be achieved at a temperature lower than 400 ℃ and a pressure higher than 0.1 MPa for the stoichiometric hydrogenation of CO, CO2, or their mixture whichever. These results should be beneficial to the design of more efficient catalysts and processes for the hydrogenation of CO and CO2 to methane.
Study on the role of atomic carbon species in cobalt-based FT synthesis catalyst
YANG Shenglong, WANG Jungang, MA Zhongyi, CHEN Congbiao, LIU Yan, ZHANG Wei, XIE Qilong, HOU Bo
 doi: 10.19906/j.cnki.JFCT.2024017
Abstract(63) HTML(29) PDF 1345KB(101)
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The FT synthesis reaction is a process that catalytically converts syngas into long-chain heavy hydrocarbons. The Fischer-Tropsch reaction involves CO activation, disproportionation reactions, and hydrocarbon dehydrogenation reactions that can form carbon species on the catalyst surface. The role of carbon species in the Fischer-Tropsch reaction has been a topic of controversy. This paper reports the successful construction of model catalysts with varying atomic carbon species content. The catalysts were prepared by pretreating single-crystal cobalt with HCP-Co(10-11) as the main exposed surface under different conditions. The carbon species content and existing forms of the catalyst were characterized by temperature programmed hydrogenation, Raman spectroscopy and infrared spectroscopy. The study found that the activity and CH4 selectivity of the catalysts were closely related to the number and form of atomic carbon species introduced. With the increase of pretreatment time, the content of atomic carbon species deposited on the catalyst first increased and then decreased, and finally maintained a dynamic equilibrium, indicating that the content of atomic carbon species would remain unchanged with the increase of pretreatment time to a certain extent. The pre-treated catalyst was characterized by XRD, and no characteristic peak of CoO was found. The crystal structure is consistent with that of P-Co catalyst, and the influence of CoO and other crystal structure on the performance of FT synthesis is excluded. The P-Co-C3 catalyst, with a carbon content of 5.72%, achieved a high CO conversion rate of 72.2%, whereas the P-Co-C2 catalyst, with a carbon content of 3.01%, had a low CH4 selectivity of 4.2%. When the carbon content of P-Co-C1 (2.76%) and P-Co-C2 (3.01%) catalysts is low, the atomic carbon species mainly exists in the form of amorphous carbon (C). The presence of amorphous carbon in atomic carbon species covers part of methane generation sites, thus inhibiting methane generation, resulting in a decrease in methane selectivity. As the carbon content of P-Co-C3 (5.72%) and P-Co-C4 (14.12%) catalysts increases, the atomic carbon species in P-Co-C3 and P-Co-C4 catalysts may mainly exist in the form of CxHy, and CxHy species plays a major role in the performance of Fischer-Tropsch reaction. It is speculated that CxHy may exist in the form of low carbon olefins in adsorbed state in the atomic carbon species on the catalyst. According to the olefin readsorption mechanism, olefin readsorption produced on the catalyst surface can be used as chain initiation and chain growth species, resulting in changes in activity. Using the same pretreatment conditions, the carbon deposition on the single crystal cobalt catalyst C−Co, whose main exposed crystal surface is HCP-Co (11-20), and the Fischer-Tropsch reaction performance evaluation. The carbon species on catalyst were analyzed by temperature programmed hydrogenation and infrared characterization, and it was found that atomic carbon species were deposited on catalyst C−Co. The results showed that the deposition of atomic carbon species on the C−Co catalyst inhibited the formation of CH4 and improved the activity of the catalyst. It is further confirmed that the presence of a few atomic carbon species on cobalt-based catalysts has a certain universality to improve the performance of Fischer-Tropsch reaction.
A research paper
Influence of Ni-Ag/SiO2 catalyst preparation method on its performance in hydrogenation of dimethyl oxalate to methyl glycolate
FANG Di, LUO Zuwei, CAO Yueqiang, ZHOU Jinghong, LI Wei
 doi: 10.19906/j.cnki.JFCT.2024020
Abstract(69) HTML(34) PDF 13365KB(4)
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Methyl glycolate (MG), as a high value-added organic chemical intermediate, possesses broad prospects for downstream applications. In this study, nickel-silver bimetallic catalysts, denoted as Ni-Ag/SiO2-p and Ni-Ag/SiO2-i, were synthesized via homogenous precipitation-impregnation and impregnation-impregnation methods, respectively, for selective hydrogenation of dimethyl oxalate (DMO) to MG. Various characterization techniques, including X-ray diffraction, infrared spectroscopy, transmission electron microscopy, N2 physisorption, and X-ray photoelectron spectroscopy, were employed to extensively analyze the catalysts' structures. The results unveiled that the Ni-Ag/SiO2-p catalyst, prepared through the precipitation of the nickel precursor followed by impregnation of the silver precursor, exhibited a laminated nickel silicate structure and a higher specific surface area compared to the Ni-Ag/SiO2-i catalyst, synthesized via sequential impregnation of both metal precursors over SiO2. This enhanced surface area facilitated improved metal-support interaction and the reduction of smaller metal particles, thereby Ni-Ag/SiO2-p demonstrated superior metal dispersion compared to Ni-Ag/SiO2-i, providing more active sites for adsorption and activation of reactant molecules. Specifically, Ni species with small particle sizes facilitated the adsorption and activation of DMO molecules , while the introduction of Ag not only promoted the adsorption of DMO molecules but also significantly enhanced the adsorption and activation capacity of H2. This resulted in H2 predominating in competitive adsorption with DMO molecules, substantially augmenting the hydrogenation activity of DMO on the catalyst. Remarkably, Ni-Ag/SiO2-p achieved outstanding results with a low Ag loading of 0.48% under operating conditions of 220 ℃, 2.0 MPa, a liquid hourly space velocity of 0.5 h-1, and a hydrogen-to-ester ratio of 50. Specifically, Ni-Ag/SiO2-p catalyst demonstrated DMO conversion and MG selectivity of 99.1% and 87.6%, respectively. These findings underscore the substantial impact of catalyst preparation method on the structure and catalytic performance of bimetallic catalysts, offering valuable insights for the design and optimization of catalysts for DMO hydrogenation to MG.
A research paper
Direct liquefaction behavior of Shenhua coal under CO containing atmosphere
TANG Bowen, ZHANG Rui, LIU Haiyun, JIN Lijun, HU Haoquan
 doi: 10.1016/S1872-5813(24)60451-2
Abstract(68) HTML(22) PDF 2373KB(5)
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Direct coal liquefaction (DCL) under CO or syngas atmosphere is beneficial to reduce the cost of hydrogen production. In this paper, the effects of CO on the liquefaction process of Shangwan coal were investigated by comparing the liquefaction behavior in three atmospheres of CO, H2, and N2. Then, the effects of different CO/H2 ratios and catalysts on the liquefaction process in syngas were investigated. The results indicated that the oil yield under the CO atmosphere reached 43.1%, which was 4.2% lower than that under H2, but 10.2% higher than that under N2. The liquefaction performance was further improved by adding the Shenhua 863 catalyst. It is analyzed that CO promoted liquefaction in two ways: water-gas shift reaction and the reaction between CO and organic structures of coal. Through the characterization of the products by GC-MS and FI-TR, it was found that CO makes the benzenes, aliphatics, and oxygen-containing compounds in liquefied oil simultaneously increased, the effect on functional groups and free radicals concentration in the solid products was not obvious. The experimental results under syngas showed that the highest oil yield, 57.4%, can be obtained in DCL with 20%CO syngas, and further improved by increasing the moisture content of coal appropriately. In addition, it was found that the Shenhua 863 catalyst has a good catalytic effect on the liquefaction process and also water-gas shift reaction. The research work provides a theoretical basis for the direct liquefaction of coal under syngas.
2024, 52(7): 1-2.  
Abstract(82) HTML(31) PDF 482KB(13)
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2024, 52(7): 1-6.  
Abstract(79) HTML(19) PDF 20620KB(26)
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Recent contributions of photoionization mass spectrometry in the study of typical solid fuel pyrolysis
SHEN Yang, CUI Cunhao, LIU Haoran, REN Hairong, CAI Jianghuai, ZHOU Zhongyue, QI Fei
2024, 52(7): 921-944.   doi: 10.1016/S1872-5813(23)60411-6
Abstract(163) HTML(56) PDF 15193KB(58)
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Pyrolysis, an economically viable method, thermochemically converts solid fuel into transportation fuels and value-added chemicals, such as clean gas, liquid fuels, and chemicals, alongside undesirable by-products. Photoionization mass spectrometry (PIMS) is a versatile technique for real-time process analysis, offering ‘soft’ ionization for complex analytes, detecting and analyzing ions during in-situ pyrolysis. This review focuses on recent applications of PIMS during pyrolysis of solid fuels (i.e. coal, biomass and energetic materials). It summarizes studies on mass spectrometric analysis combined with different reactors and highlights the benefits through online PIMS as a diagnostic tool for in-situ analysis. It provides an overview of interplay between experimental advancements and models and discusses future perspectives, potential applications in support of mechanistic studies.
Recent advances in the preparation of high-value-added chemicals by catalytic hydrogenolysis of lignin
LIU Juping, TANG Ziyue, CHEN Yingquan, WANG Xianhua, CHEN Hanping, YANG Yang, YANG Haiping
2024, 52(7): 945-958.   doi: 10.19906/j.cnki.JFCT.2024009
Abstract(235) HTML(65) PDF 4447KB(58)
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The development and utilization of renewable biomass resources is an effective way to achieve CO2 reduction. Biomass has a complex structure with low overall reactivity and utilization. Lignin is the only renewable aromatic polymer with high energy density in nature, and its conversion and utilization have attracted much attention worldwide. However, the complexity of the lignin structure, the uncertainty of the linkages, the stability of the side-chain connections, and the inevitable recondensation of the reactive fragments make the depolymerization of lignin into biofuels or aromatic chemicals a formidable challenge. Catalytic hydrogenolysis technology converts lignin into highly selective, high-yield phenolic monomers with high heating value, low oxygen content, and high carbon utilization of the product. However, the mechanism of the conversion between products and structures remains unclear with respect to the directed bond shearing during the catalytic depolymerization of lignin. In this paper, in view of the latest research progress on the catalytic hydrogenolysis of lignin for the production of high-value chemicals. We focus on the catalytic hydrogenolysis of lignin to summarize the coupling correlation between the catalysts and their products of high-value chemicals and focus on the influence of different catalyst systems on the process mechanism of lignin depolymerization products. For metal-based catalysts in particular, a detailed review of recent advances in the effects of noble metal-based catalysts, transition metal-based catalysts, hydrotalcite catalysts, and metal-organic framework catalysts on product distribution is presented. And further summarized the problems and conversion mechanisms of different catalysts. Meanwhile, the solvent in the lignin catalytic hydrogenolysis cracking process is the key to promote lignin dissolution, accelerating the heat and mass transfer, and promoting the homogeneous dispersion of reactants and catalysts in the reactor. In this paper, the main solvents for lignin liquefaction, such as water, alcohol, and new solvent systems, are reviewed for their depolymerization impact on lignin. And further, outline the effect of the solvent system on the properties of lignin conversion products. Nevertheless, there are still many difficulties in the catalytic hydrogenolysis of lignin for the preparation of high-value chemicals. The complexity of the macromolecular structure of lignin, the directed depolymerization of the C−O and C−C structures is still difficult, and the preparation of efficient catalysts as well as the mechanism of directional regulation of the products are still to be further investigated. Due to the insolubility of lignin, no solvent system that can completely dissolve lignin has been found yet; secondly, the research on the solvent effect is still only in the preliminary exploration stage. Novel technology for favorable conversion of lignin is still only at the stage of laboratory research. And the efficient conversion of renewable lignin into valuable chemicals and fuels is of great significance in solving the energy crisis and slowing down global warming, and at the same time, it will help our country to realize the energy-dependence transition from oil to renewable biomass. So finally, the opportunities and challenges facing the field are summarized and outlooked, providing a theoretical reference for efficient targeted conversion and high-value utilization of lignin.
Theoretical study on the pyrolysis mechanism of the lignin dimer model compound catalyzed by alkaline earth metal ions Ca2+ and Mg2+
JIANG Xiaoyan, LI Yiming, TANG Li, DU Xiaojiao, DAI Lanhua, HU Bin
2024, 52(7): 959-966.   doi: 10.1016/S1872-5813(24)60441-X
Abstract(93) HTML(51) PDF 2730KB(38)
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It is essential to investigate the influence of alkaline earth metals on the pyrolysis mechanism and resulting products of lignin to enhance the efficient thermochemical conversion and utilization of lignin or biomass. In this study, the density functional theory method was used to simulate the pyrolytic reaction pathways of a β-O-4 type lignin dimer model compound (1-methoxy-2-(4-methoxyphenethoxy)benzene, mc) affected by alkaline earth metal ions Ca2+ and Mg2+. The computational findings suggest that Ca2+ and Mg2+ tend to combine with the oxygen atom at the Cβ position and the oxygen atom on the methoxy group of the lignin dimer model compound, forming stable complexes that modify the bond lengths of the Cα–Cβ and Cβ–O bonds and affect their pyrolysis energy barriers. During the catalytic pyrolysis process, the presence of Ca2+ and Mg2+ can promote the concerted decomposition reaction, leading to increased production of products like 1-methoxy-4-vinylbenzene, 2-methoxyphenol and catechol. Meanwhile, they can suppress homolytic cleavage reactions of the Cβ–O and Cα–Cβ bonds, thereby hindering the formation of other products such as 1-ethyl-4-methoxybenzene and 2-hydroxybenzaldehyde.
The effect of alkali and alkaline earth metals in biomass ash on the bio-oil components derived from biomass fast pyrolysis
DING Zixia, CAI Bo, CEN Kehui, CHEN Dengyu, MA Zhongqing
2024, 52(7): 967-975.   doi: 10.19906/j.cnki.JFCT.2023076
Abstract(218) HTML(68) PDF 3431KB(54)
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The alkali and alkaline earth metals (AAEMs) in biomass ash have a significant impact on the yield and component distribution of rapid plytic biooil. In this paper, corn straw is selected as the raw material. First, the effect of cascade deash removal pretreatment (distillation water, ammonium acetate and hydrochloric acid) on the selective removal of AAEMs and its biological oil components is studied, and then the effect of the type of AAEMs (K, Ca, Na and Mg), the concentration of chloride salt (0.5%, 2.5% and 5%), and the acid radical in metal salt(${\rm{SO}}_4^{2-} $, ${\rm{NO}}_3^- $, ${\rm{CO}}_3^{2-} $, ${\rm{HCO}}_3^- $, AC and ${\rm{PO}}_4^{3-} $)on the compound distribution of bio-oil was systematically investigated. The results show that in the process of ash removal pretreatment, with the deepening of the acidity of the ash removal solution, the removal rate of AAEMs gradually increases. According to the selective removal law of AAEMs in the process of cascade ash removal, their morphology in biomass can be divided into the following three groups, namely the water-soluble metal (K), the ion-exchanged metals (Ca and Mg), the acid-soluble metal (Na). The removal of AAEMs promoted the formation of levoglucosan (LG), while restrained the formation of ketones and furans. However, the incorporation of AAEMs in biomass presented an opposite variation trend. The AAEMs would act as catalyst during biomass pyrolysis which promoted the secondary cracking of LG, leading to the reduction of LG and increase of ketones and furans. In addition, different acid roots in potassium salt also have remarkable influence on the secondary cracking reaction of LG and the rupture of the aryl ether bond and the phenolic hydroxyl group in lignin. The influence of the acid roots on the secondary cracking reaction of LG was in the order of ${\rm{HCO}}_3^- $>${\rm{CO}}_3^{2-} $>AC>${\rm{PO}}_4^{3-} $>Cl>${\rm{NO}}_3^- $>${\rm{SO}}_4^{2-} $, while the influence of acid roots on the rupture of the aryl ether bond and the phenolic hydroxyl group was in the order of ${\rm{CO}}_3^{2-} $>Cl>${\rm{HCO}}_3^- $>${\rm{PO}}_4^{3-} $≈AC>${\rm{SO}}_4^{2-} $≈${\rm{NO}}_3^- $.
Catalytic pyrolysis of waste biomass to produce hydrogen-rich gas:Influence of catalyst performance
LI Xueqin, LIU Peng, LU Yan, WANG Zhiwei, WU Youqing, LEI Tingzhou
2024, 52(7): 976-987.   doi: 10.19906/j.cnki.JFCT.2024011
Abstract(143) HTML(37) PDF 9093KB(40)
Abstract:
Catalytic pyrolysis of waste biomass is a promising method for the production of hydrogen-rich gas. HZSM-5 carrier is the premise of ensuring the thermal stability and long life of catalytic materials, and plays a mechanical role in bearing the active component nickel (Ni). At the same time, aluminum ash (ASA), as an important waste in the production process of aluminum industry, is mainly composed of Al2O3 and a large number of heavy metal oxides such as Na2O, CaO, MgO, Fe2O3 and so on. In this study, aiming at the technical bottleneck problems such as the low performance of traditional HZSM-5 molecular sieve and the difficulty of resource utilization of aluminum ash, the active component nickel (Ni) and promoter iron (Fe) were combined with HZSM-5 molecular sieve by ultrasonic-assisted excessive impregnation to improve the yield of hydrogen-rich gas. Furthermore, waste aluminum ash (ASA) and HZSM-5 molecular sieve were used as co-carriers to prepare aluminum ash co-supported Ni-Fe catalyst with HZSM-5 molecular sieve, and it was used to enhance the process of hydrogen-rich gas production by the catalytic pyrolysis of biomass. The results showed that the heat transfer efficiency decreased with the increase of heating rate during pyrolysis of biomass. After compensation, the apparent kinetic parameters (E and A) of pyrolysis of different biomass were obtained. At the pyrolysis temperature of 700 ℃, Ni-Fe/HZSM-5 catalyst increased the yield of hydrogen-rich gas to 56.49% (about 230.59 mL/g), hydrogen yield to 63.12%, hydrogen production efficiency to 0.71%, and CO yield to 65.77 mL/g. Sufficient amount of Ni-Fe/HZSM-5 catalyst enhanced the pathway of hydrogen production by the catalytic pyrolysis of biomass, promoted the gasification reaction of carbon deposition, and played a dual role in increasing the yield of H2 and CO. The synergism between HZSM-5 and ASA carriers enhanced the reforming process of CH4 and CO2, inhibited the reverse water vapor shift reaction, obtained 53.37% and 41.56% gas and tar yields. At the same time, the gasification reaction of carbon deposition was also accelerated, reduced the char yield to 5.07%, and obtained the carbon deposition of 0.05 g/g. Ni-Fe/ASA@HZSM-5 had good thermal cracking ability and deoxidization ability, which was helpful to promote the formation of hydrogen-rich gas on HZSM-5 as a base catalyst. From the point of view of proximate analysis and chemical composition of biomass, the composition of different kinds of biomass varied greatly, and the product distribution of catalytic pyrolysis also had a great influence. The order of gas yield of pyrolysis of biomass catalyzed by Ni-Fe/HZSM-5 was PR (74.21%) > WSt (54.71%) > CR (53.5%) > MCh (52.47%) > WSh (52.10%) > CS (46.49%), which provided theoretical support for the development of deep purification and efficient utilization of high temperature pyrolysis gas, and effectively guided the development of a new double catalytic bed for multi-stage catalytic reforming.
Research on the 9,10-dihyroanthrancene assisted catalytic pyrolysis of pine over nitrogen-doped activated carbon for preparation of alkoxyphenols
LI Wentao, ZHANG Chengbo, LI Kai, NIU Qi, LI Jihong, LU Qiang, JIA Bao, GAO Lijuan
2024, 52(7): 988-994.   doi: 10.19906/j.cnki.JFCT.2023081
Abstract(107) HTML(56) PDF 5141KB(28)
Abstract:
In this study, nitrogen-doped activated carbon (NAC) was prepared from walnut shell and applied to the catalytic pyrolysis of pine for selective preparation of alkoxyphenols with 9,10-dihyroanthrancene (DHA) as the hydrogen donor. The effects of the mass fraction of ammonia solution on the physicochemical properties of NAC were investigated. The regulatory functions of DHA/pine ratio, pyrolysis temperature, and NAC/pine ratio on the generation of alkoxyphenols were revealed. The results showed that the pore structure and active sites distribution of NAC could be improved by proper mass fraction of ammonia solution. The NAC prepared at mass fraction of ammonia solution of 15% was the best for the production of alkoxylphenols. The yield of alkoxylphenols reached its maximum value of 5.27% at DHA/pine ratio of 1, pyrolysis temperature of 550 ℃, and NAC/pine mass ratio of 3, which was much higher than that from catalytic pyrolysis of pure pine (1.74%).
Experimental study on alkali lignin enhanced chemical looping gasification of pulverized coal char
GAO Xinglong, AN Fengxia, HU Yun, CHEN Guoqing, YI Qun, WU Xiaoyan, CAO Jinzeng, YAO Weishan, WEI Guoqiang
2024, 52(7): 995-1005.   doi: 10.19906/j.cnki.JFCT.2023078
Abstract(197) HTML(97) PDF 4595KB(35)
Abstract:
The pulverized coal char from the byproduct of China's coal coking industry has high yield and low activity, which is difficult to be directly recycled. The conventional thermochemical utilization method has harsh reaction conditions, catalyst deactivation and kinetic limitations. By using the alkali lignin from paper-making as a disposable catalyst, an alkali lignin enhanced chemical looping gasification method was constructed to treat coal coke powder, which can realize the collaborative resource utilization of industrial by-products. In this study, the reaction process of alkali lignin and coal char powder was studied by thermogravimetry and kinetic analysis. The thermal transformation experiment and kinetic analysis showed that alkali lignin could strengthen the chemical looping gasification process of pulverized coal char and promote the pyrolysis peak to move to low temperature. When the mass ratio of pulverized coal char to alkali lignin was 1∶3, the activation energy was 87.56% lower than that of coal coke powder alone, indicating that there was a synergistic effect between the two in the co pyrolysis process. The experiments in fixed bed reactor verified that the carbon conversion rate and the selectivity of syngas increased as the increasing of temperature and the content of alkali lignin and oxygen carrier, which effectively promoted the gasification reaction. However, excessive oxygen loading led to combustion reaction between syngas and lattice oxygen and reduce syngas selectivity. Under the optimal reaction conditions of 950 ℃, the mass ratio of coal char powder to alkali lignin was 1∶2, and the mass ratio of oxygen carrier to pulverized coal char/alkali lignin was 1∶1, the selectivity of syngas of alkali lignin/coal char powder in chemical looping gasification was 82.85%. This study provides a scientific basis for the resource utilization of alkali lignin and coal char powder.
Impact of B-site cations of MgX2O4 (X=Cr, Fe, Mn) spinels on the chemical looping oxidative dehydrogenation of ethane to ethylene
LIANG Xiaocen, WANG Xuemei, XING Zifan, MAO Min, SONG Da, LI Yang, LONG Tao, ZHOU Yuchao, CHEN Peili, HE Fang
2024, 52(7): 1006-1019.   doi: 10.1016/S1872-5813(24)60434-2
Abstract(96) HTML(45) PDF 9274KB(35)
Abstract:
Chemical looping oxidative dehydrogenation (CL-ODH) provides a multifunctional conversion platform that can take advantage of the selective oxidation of lattice oxygen in oxygen carrier to achieve high-valued ethane to ethylene conversion. In this study, we explored the effect of B-site element in MgX2O4 (X=Cr, Fe, or Mn) spinel-type oxygen carriers on the performance of ethane CL-ODH. The properties test and characterization of MgX2O4 spinel were tested by fixed bed and H2-TPR, O2-TPD, TG, in-situ Raman, SEM, and TEM. The results showed that because MgCr2O4 only released a small amount of adsorbed surface oxygen, it tended to catalyze the conversion of ethane to coke and hydrogen. MgFe2O4 facilitated the deep oxidation of ethane into CO2 by providing more surface lattice oxygen. Meanwhile, since a significant amount of bulk lattice oxygen was released by the MgMn2O4 oxygen carrier, it could burn hydrogen in a targeted manner to advance the reaction and increased ethylene's selectivity. Thereby, MgMn2O4 achieved an ethane conversion of 73.72% with an ethylene selectivity of 81.46%. Furthermore, the MgMn2O4 catalyst demonstrated stable reactivity and an ethylene yield of about 62.00% in ethane CL-ODH over the 30 redox cycles. The screening tests indicated that the B-site elements in MgX2O4 spinel oxides could significantly influence their ability to supply lattice oxygen, thereby affecting their performance in ethane CL-ODH reaction.
Research progress of calcium-based adsorbents for CO2 capture and anti-sintering modification
GENG Yi-qi, GUO Yan-xia, FAN Biao, CHENG Fang-qin, CHENG Huai-gang
2021, 49(7): 998-1013.   doi: 10.1016/S1872-5813(21)60040-3
[Abstract](1505) [FullText HTML](263) [PDF 1222KB](179)
摘要:
利用CaO基吸附剂直接从高温烟气中捕集CO2因成本低、吸附性能好等优点成为CCUS(碳捕集、利用与封存)的重要技术之一。但CaO基吸附剂在碳酸化/煅烧吸脱附循环过程中存在易烧结的问题,导致其吸附性能急剧下降。本研究针对CaO基吸附剂全面总结了其吸附CO2的动力学、热力学及烧结机理,并重点综述了世界各国研究者在CaO基吸附剂抗烧结改性方面所做的研究,指出了各种方法的优点及其局限性。结果表明,水合作用改性可使吸附剂崩塌而获得更大的比表面积;酸溶液改性会在制备过程产生更多的气体和小分子物质提高吸附剂孔隙率;掺杂改性可以促进CaO对CO2的吸附和扩散,还可作为骨架分离CaO颗粒。经比较,掺杂改性工艺简单、性能好,是比较有前景的改性方法,以含钙固废制备抗烧结改性吸附剂是发展方向。
Structural features and combustion reactivity of residual carbon in fine slag from entrained-flow gasification
LÜ Deng-pan, BAI Yong-hui, WANG Jiao-fei, SONG Xu-dong, SU Wei-guang, YU Guang-suo, ZHU he, TANG Guang-jun
2021, 49(2): 129-136.   doi: 10.1016/S1872-5813(21)60011-7
[Abstract](695) [FullText HTML](149) [PDF 1332KB](146)
摘要:
气流床气化过程中产生的细渣含碳量很高,目前多以填埋的方式进行处理,将细渣用于循环流化床锅炉掺烧有望为细渣处理提供有利的技术。本研究选用宁东能源化工基地典型气化工艺GE、OMB及GSP产生的气化细渣为研究对象,利用物理吸附仪、激光拉曼及热重分析仪等仪器,系统研究了气化细渣中残炭的结构特征与燃烧特性。结果表明,原始气化细渣中的物质可分为黏结球形颗粒、多孔不规则颗粒与孤立的大球形颗粒,而酸洗后的气化细渣多以疏松细小的颗粒和多孔不规则块状颗粒存在;细渣中残炭的孔径尺寸主要分布在4−8 nm,且比表面积与残炭的活性位点大小顺序均为:GE > OMB > GSP;GE渣中残炭结构有序度最低,无定形炭结构最多,GSP则相反;GE渣中残炭燃烧速率最快,主要是由于GE渣中残炭有较大的比表面积、较多的无定形炭结构及较高的的活性位点,且GE渣中残炭的综合燃烧指数为5.26 × 10−7%2/(min2·℃3)。
An analysis of waste gasification and its contribution to China’s transition towards carbon neutrality and zero waste cities
LEE Roh Pin, SEIDL Ludwig Georg, HUANG Qiu-liang, MEYER Bernd
2021, 49(8): 1057-1076.   doi: 10.1016/S1872-5813(21)60093-2
[Abstract](1150) [FullText HTML](306) [PDF 1125KB](129)
摘要:
Waste gasification has the potential to contribute to China’s transition towards carbon neutrality and zero waste cities via the recirculation of waste as secondary carbon feedstock for the production of chemicals with lower/and or zero carbon footprint, green hydrogen with zero carbon footprint and CO2-neutral synthetic liquid fuels. With China’s significant coal gasification capacity and associated experiences and expertise, Coal-to-X could act as a bridge to Waste-to-X for carbon intensive sectors such as the waste management, chemical production and mobility sectors. To illustrate the opportunities in these areas, this article presented highlights from dynamic global developments in waste gasification, focusing on pioneering industrial developments in Germany between 1980−2000’s as well as current international developments. Lessons learnt from previous and current waste gasification project deployment are shared and enabled the identification of problems which will have to be addressed in the transition from coal gasification towards mono-waste gasification technologies. Additionally, a qualitative evaluation of gasification technologies pointed to the strengths and weaknesses of fixed-bed, fluidized-bed and entrained-flow gasification principles in their application for waste gasification.
Research progress on NH3-SCR mechanism of metal-supported zeolite catalysts
ZHANG Wen-bo, CHEN Jia-ling, GUO Li, ZHENG Wei, WANG Guang-hua, ZHENG Shen-ke, WU Xiao-qin
2021, 49(9): 1294-1315.   doi: 10.1016/S1872-5813(21)60080-4
[Abstract](1222) [FullText HTML](287) [PDF 1005KB](171)
摘要:
在NH3选择性催化还原(NH3-SCR)反应中,由于具有宽温度窗口和良好的水热稳定性,金属负载型分子筛是具有广泛应用潜力的脱硝催化剂。本文综述了Cu基和Fe基分子筛催化剂在NH3-SCR领域的研究进展,总结了催化剂的结构特征和NH3-SCR性能指标,并对相应的金属活性位点和反应机理进行了归纳。此外,系统介绍了密度泛函理论(DFT)计算在NH3-SCR反应机理中的应用及反应动力学的研究方法,并对比了不同催化剂体系下的表观动力学参数,为进一步研究金属负载型分子筛催化剂的NH3-SCR反应机理提供方法与思路。
Characteristics of MSWI fly ash with acid leaching treatment
CAO Yi-nan, LUO Jin-jing, SUN Shi-qiang
2021, 49(8): 1208-1218.   doi: 10.1016/S1872-5813(21)60119-6
[Abstract](305) [FullText HTML](92) [PDF 852KB](28)
摘要:
The chemical and mineralogical characteristics of fly ash from a municipal solid waste incineration (MSWI) in China and the influence of processing parameters on heavy metals removal during leaching were investigated in this work. The fly ash particles had complex surface structure with limited specific surface area. The alkali chloride and metal salts in MSWI fly ash showed evidently impact on leaching efficiency. Metal leachability was related to their properties and speciation in fly ash. Water-soluble salts such as KCl, NaCl and CaCl2 in fly ash were easily washed out. In this study, removal efficiency by water washing was achieved to 93.1% for Cl, 41.4% for Na, 48.5% for K and 24.8% for Ca, respectively. Mineralogical analysis also revealed change of fly ash mineral phases and specification distribution after water washing. Under liquid to solid ratio of 40∶1 L/kg and treatment time of 120 min, the leaching process achieved high dropping yields of toxicity characteristic leaching procedure (TCLP) concentrations for Cu, Zn Cd and Pb (80%−100%), moderate dropping yields for As (30%−80%) and relatively low dropping yields of Ni (< 30%). In addition, heavy metals such as Pb and Zn in fly ash with twice water washing treatment at a low liquid-solid ratio could reach lower TCLP concentrations. The result indicated that the combination process of twice water washing and one acid washing could significantly reduce the environmental risk of MSWI fly ash.
Effect of preparation methods on the structure and catalytic performance of CeO2 for toluene combustion
QUAN Yan-hong, MIAO Chao, LI Tao, WANG Na, WU Meng-meng, ZHANG Ning, ZHAO Jin-xian, REN Jun
2021, 49(2): 211-219.   doi: 10.1016/S1872-5813(21)60014-2
[Abstract](591) [FullText HTML](117) [PDF 1338KB](60)
摘要:
采用溶胶-凝胶-超临界干燥法、水热法及共沉淀法分别合成了氧化铈气凝胶(CeO2-A)、纳米棒(CeO2-R)和纳米片(CeO2-F)。考察了不同形貌氧化铈的催化燃烧甲苯性能,通过多种方法分析表征了氧化铈样品的微观结构,讨论了不同方法制得的CeO2形貌结构对催化性能的影响。结果表明,CeO2-R和CeO2-F比表面积较低,并且仅暴露(111)晶面,催化燃烧甲苯活性较低。CeO2-A具有高比表面积和丰富的孔道结构,有利于反应物分子的吸附,而且同时暴露(100)和(111)两种活性晶面,增加了氧空位浓度(Osur/Olatt = 0.25)。此外,CeO2-A由于表面晶格氧移动性较强,有利于Ce3+/Ce4+氧化还原的循环,加快甲苯深度氧化反应的进行。因此,CeO2-A具有更加优异的催化燃烧甲苯活性,t50t90分别为223 和239 ℃,这主要归因于其大比表面积、高暴露活性晶面以及强晶格氧迁移性。
Lead poisoning and regeneration of Mn-Ce/TiO2 catalysts for NH3-SCR of NOx at low temperature
YAN Dong-jie, GUO Tong, YU Ya, CHEN Zhao-hui
2021, 49(1): 113-120.   doi: 10.1016/S1872-5813(21)60003-8
[Abstract](326) [FullText HTML](226) [PDF 1677KB](103)
摘要:
考察了Pb对Mn-Ce/TiO2低温选择性催化还原(SCR)脱硝活性的影响,并对Pb中毒的催化剂进行了再生;结合氮吸附、SEM、XRD、FT-IR、H2-TPR和NH3-TPD等表征结果,研究了Mn-Ce/TiO2催化剂Pb中毒和再生活性恢复的原因。结果表明,Pb对Mn-Ce/TiO2催化剂脱硝活性有明显的抑制作用;当Pb的含量为11%时,Mn-Ce/TiO2催化剂在180 ℃下的脱硝效率从原来100%下降至44%。Pb在Mn-Ce/TiO2中的掺杂使得催化剂的比表面积以及活性组分Mn4+和Ce3+的含量降低,影响了氧化还原循环反应(Mn4+ + Ce3+ ↔ Mn3+ + Ce4+)的进行;此外,Pb的加入破坏了催化剂的酸性位点,阻碍了催化剂对NH3的吸附和活化。经硝酸再生后的Mn-Ce/TiO2催化剂的脱硝活性几乎完全恢复,在80–150 ℃下其脱硝活性甚至超过新鲜未中毒的催化剂,其原因主要在于硝酸再生能恢复催化剂的氧化还原能力、增大比表面积、并形成新的酸位点。
In-situ catalytic upgrading of tar from integrated process of coal pyrolysis with steam reforming of methane over carbon based Ni catalyst
WANG Zheng-wei, WEI Bao-yong, LÜ Jian-nan, WANG Yi-ming, WU Yun-fei, YANG He, HU Hao-quan
2022, 50(2): 129-142.   doi: 10.1016/S1872-5813(21)60169-X
[Abstract](2315) [FullText HTML](131) [PDF 2200KB](74)
摘要:
In order to improve the tar quality by decreasing the heavy tar content and ensuring high tar yield, in-situ catalytic upgrading of tar from the integrated process of coal pyrolysis coupled with steam reforming of methane was conducted over carbon (KD-9) based Ni catalyst. The results show that at 650 °C, the tar yield of CP-SRM over 5Ni/KD-9 is 24.4%, which is a little lower than that of without catalyst, while the light tar yield (i.e.,18.9%) is 1.4 times higher than that of without catalyst, and the content of C2, C3 and C4 alkyl used as a substitute for benzene significantly increases tar yields by 0.5, 0.6 and 4.0 times, respectively. The content of phenols and naphthalenes in tar also increases dramatically after upgrading. Isotope tracer approach combined with the mass spectra of typical components was employed in exploring the mechanism of the upgrading process. The results show that 5Ni/KD-9 catalyzes coal tar cracking and SRM at the same time. Small free radicals such as ·CHx, ·H and ·OH generated by SRM can combine with free radicals from tar cracking, thus avoiding excessive cracking of tar.
Advances on the catalytic hydrogenation of biomass-derived furfural and 5-hydroxymethylfurfural
ZHANG Jun, LI Dan-ni, YUAN Hao-ran, WANG Shu-rong, CHEN Yong
2021, 49(12): 1752-1767.   doi: 10.1016/S1872-5813(21)60135-4
[Abstract](4199) [FullText HTML](766) [PDF 1220KB](373)
摘要:
近年来,利用生物质基平台化合物转化制备各种燃料及高值化学品引起研究人员的广泛关注。5-羟甲基糠醛(HMF)和糠醛(FFR)作为一类重要的生物质衍生平台化合物,分子结构中醛基和呋喃环等官能团赋予其独特的化学性质。本综述针对HMF和FFR在氢气、低碳醇、甲酸和硅烷等不同氢源中的催化加氢反应研究现状进行了阐述,对加氢转化过程中的主要影响因素如催化剂类型和反应条件以及反应机理等进行了详细分析,同时对HMF/FFR加氢转化应用研究前景进行了展望。
Research progresses in the hydrogenation of carbon dioxide to certain hydrocarbon products
WANG Han, FAN Sheng, WANG Sen, DONG Mei, QIN Zhang-feng, FAN Wei-bin, WANG Jian-guo
2021, 49(11): 1609-1619.   doi: 10.1016/S1872-5813(21)60122-6
[Abstract](3378) [FullText HTML](275) [PDF 905KB](226)
摘要:
化石资源的大量使用导致CO2的大量排放,带来了严重的环境问题。与此同时,CO2又是一种清洁、无毒的含碳资源。将CO2作为原料,直接转化制备重要化学品,不仅可以减缓温室效应,同时也是一条有效利用含碳资源制备清洁燃料和化学品的新路线。本文概述了近年来关于CO2加氢制备一些烃类化合物(主要包括甲烷、烯烃和芳烃)的相关研究进展;重点分析了CO2加氢制烃类化合物相关过程催化剂的研发状态和对催化反应机理的认识,并对CO2加氢转化利用的未来发展进行了展望。
Preparation of core-shell catalysts for one-step synthesis of dimethyl ether from syngas
WANG Wen-li, WANG Yan, CHEN Yue-xian, ZHAO Wen-chao, LI Rui-feng
2013, 41(08): 1003-1009.  
[Abstract](2457) [PDF 13334KB](56)
Abstract:
A core-shell catalyst CuO-ZnO-Al2O3@Al2O3 for one-step synthesis of dimethyl ether from synthesis gas was prepared using glucose, sucrose or starch as template, and characterized by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The thickness of the Al2O3 shell in the catalyst was altered by controlling the synthesis condition, such as temperature and time. The catalytic performance of dimethyl ether (DME) synthesized from CO hydrogenation on the catalysts were investigated. The conversion of CO and the selectivity of DME on CuO-ZnO-Al2O3@Al2O3 achieved 35.2% and 61.1% at 260 ℃, 5.0 MPa and 1 500 mL/(h·gcat), respectively.
Effect of wastewater treatment processes on thermal treatment properties of sewage sludge
JIE Li-Beng, Zheng-Shi-Mei, LI Chao
2009, 37(04): 501-505.  
[Abstract](1759) [PDF 1335KB](64)
Abstract:
The properties of pyrolysis and combustion for five different sewage sludges are studied by thermal gravimetric analysis at a heating rate of 10℃/min in the atomosphere of nitrogen and oxygen, respectively. The results show that both of the “anaerobic” wastewater treatment and the sludge anaerobic digestion make the organic compounds in sludge so complicated that the organic compounds decomposition and release temperature becomes higher during pyrolyzing, and the “aerobic + anaerobic” process makes the organic compounds in sludge more complicated than the “anaerobic +aerobic” process. There is no influence on the combustion process and the burnout point, but can make the combustion temperature of sludge higher. The thermal reaction mechanisms have been studied with šatava-šesták equation. It shows that the pyrolysis mechanism of these sludges is a process of volatile diffusion at first and then the chemical reaction function, while the combustion mechanism of them is a process of chemical reaction and diffusion function.