Pore structure modulation of Cu-ZnO-ZrO2 catalysts for methanol production from CO2 hydrogenation
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摘要: 采用胶质晶体模板法制备了不同孔径Cu-ZnO-ZrO2（CZZ）催化剂，并对其CO2加氢制甲醇性能进行了研究。结果表明，通过改变催化剂孔径可以实现ZnO粒径大小的调控，较小的粒径表现出更卓越的催化性能。其中，在孔径为55 nm的（CZZ-55）样品上，ZnO粒径为14.5 nm，CO2转化率为14.83%，甲醇选择性为78.8%，甲醇产率可达345.8 g/(kg·h)。原位漫反射傅里叶变换红外光谱结果表明，在CZZ催化剂上CO2加氢制甲醇遵循甲酸盐路径，ZnO-ZrO2界面是CO2吸附和活化的活性位点，而三维有序大孔结构有助于形成更分散的ZnO-ZrO2活性位，提高了CO2转化率。并且孔径大小对中间体的转化具有一定影响，孔径越小，甲酸盐更容易转化为甲醇。此外，三维有序的大孔结构为产物（水汽和甲醇）快速扩散提供了“高速通道”，有效抑制CO2加氢的副产物水汽对活性位的毒化作用，较大程度提高了催化剂的稳定性，在600 h内无明显失活。Abstract: 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.
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Key words:
- CO2 hydrogenation to methanol /
- pore size control /
- ZnO particle size /
- formate /
- stability
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图 1 PMMA晶体模板，粒径(a): 300 nm; (b): 150 nm; (c) and (d): 90 nm
Figure 1 PMMA crystal templates, particle size(a): 300 nm; (b): 150 nm; (c) and (d): 90 nm
图 2 （a）3DOM催化剂制备流程；（b）和（b1） CZZ-CP、（c）和（c1） CZZ-220、（d）和（d1） CZZ-55催化剂的SEM图像
Figure 2 (a) Flow chart of 3DOM catalyst preparation; SEM images of (b) and (b1) CZZ-CP, (c) and (c1) CZZ-220,(d) and (d1) CZZ-55 catalysts
图 5 （a）、（e） CZZ-CP、（b）、（f） CZZ-220 和（c）、（g） CZZ-55样品的TEM图像和ZnO粒径分布；（d）催化剂还原后的XRD谱图
Figure 5 TEM images and ZnO particle size distributions of (a), (e) CZZ-CP, (b), (f) CZZ-220, (c), (g) CZZ-55; (d) XRD patterns of catalysts after reduction
图 6 温度对CO2转化率和CH3OH选择性的影响（（a） CZZ-CP、（b） CZZ-220、（c） CZZ-55）；（d） 温度与CH3OH的时空产率（STY）之间的关系；（e） Cu和（f）ZnO粒径大小与催化性能函数
Figure 6 Effect of temperature on CO2 conversion and CH3OH selectivity ((a) CZZ-CP, (b) CZZ-220, (c) CZZ-55); (d) The relationship between temperature and space time yield (STY) of CH3OH; Performance as a function of particle size of (e) Cu and (f) ZnO different sizesCondition: 4 MPa, CO2/H2/Ar = 23∶69∶8, mcat = 0.3 g, GHSV = 9000 cm3/(g·h).
图 7 （a） 催化剂稳定性测试；（b） 反应后的X射线衍射（XRD）图像；（c） 还原和反应后的粒度比较；（d） 普通铜基催化剂和3DOM铜基催化剂反应前后活性位点的变化
Figure 7 (a) Catalyst stability test; (b) X-ray diffraction (XRD) image after reaction; (c) Comparison of particle size after reduction and reaction; (d) The change of active site before and after the reaction of common Cu-based catalyst and 3DOM Cu-based catalystCondition: 4 MPa, t = 220 ℃, CO2/H2/Ar = 23∶69∶8, mcat = 0.3 g, GHSV = 9000 cm3/(g·h).
图 8 （a） H2程序升温还原曲线（H2-TPR）；（b） CO2程序升温解吸曲线（CO2-TPD）
Figure 8 (a) H2 temperature-programmed reduction profiles (H2-TPR); (b) CO2 temperature-programmed desorption profiles (CO2-TPD)
图 10 （a） CZZ-CP、（b） CZZ-220 和（c） CZZ-55催化剂的原位DRIFT谱图；实验过程中生成的中间产物的峰面积（（d） HCOO*，（e） CH3O*，（f） CH3OH）
Figure 10 In-situ DRIFT spectra of (a) CZZ-CP, (b) CZZ-220, (c) CZZ-55 catalysts at 220 °C under high pressure; peak areas of generated intermediate species during the experiments: areas normalized to the values observed at the end of the transient ((d) HCOO*, (e) CH3O*, (f) CH3OH)Reaction conditions: gas flow rate = 45 mL/min, t = 220 ℃, CO2/H2/N2 = 23∶69∶8, p= 3.0 MPa; spectra referenced to specimen under 3 MPa N2 at 220 °C.
图 11 （a） CZZ-CP、（b） CZZ-55、（c） ZnO/Cu-ZrO2-55 和（d） Cu-ZrO2-55材料的原位DRIFT谱图；实验期间生成的中间物种的峰值面积（（e） CO3 2−和CH3O*，（f） HCOO*）
Figure 11 In-situ DRIFT spectra of (a) CZZ-CP, (b) CZZ-55, (c) ZnO/Cu-ZrO2-55, (d) Cu-ZrO2-55 materials at atmospheric pressure at 220 ℃, converting CO2 (CO2 has been vented into the chamber for 15 min) to H2 at a flow rate of 45 mL/min; peak areas of generated intermediate species during the experiments: areas normalized to the values observed at the end of the transient; (e) CO3 2− and CH3O*, (f) HCOO*Reaction conditions for in-situ DRIFT spectra: gas flow rate = 45 mL/min, t = 220 ℃, 10% CO2/N2 and10% H2/N2, p = 0.01 MPa; spectra referenced to specimen under 0.01 MPa N2 at 220 °C.
表 1 粒径统计
Table 1 Particle size statistics
Catalyst dCu/nm dZnO/nm $ d_{ {\mathrm{ZrO} }_2} $/nm CZZ-CP 15 22.5 4 CZZ-220 21.5 15.5 4 CZZ-55 18 14.5 4 Note: Calculation of particle size according to the XRD Scheller formula. 
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表 2 典型的Cu-ZnO-ZrO2催化剂的催化性能
Table 2 Catalytic performance of a typical Cu-ZnO-ZrO2 catalysts
Catalyst H2/CO2
ratioT/℃ P/MPa Conv./% Sel./% STY/
(g·kg−1·h−1)Cu-ZnO-ZrO2[9] 3∶1 250 3.0 19.2 30.6 37.6 Cu-ZnO-ZrO2[10] 3∶1 260 4.0 18.7 52.0 216.7 Cu-ZnO-ZrO2[11] 3∶1 220 3.0 5.2 81.0 83.1 Cu-ZnO-ZrO2[12] 3∶1 220 3.0 18.2 80.2 297 Cu-ZnO-ZrO2[13] 3∶1 280 3.0 14.25 25.0 105.5 Cu-ZnO-ZrO2[18] 3∶1 240 3.0 17.0 41.5 48.8 Cu-ZnO-ZrO2[19] 3∶1 260 3.0 19.4 29.3 60 Cu-ZnO-ZrO2[20] 3∶1 240 3.0 18.0 51.2 302 Cu-ZnO-ZrO2[21] 3∶1 230 3.0 19.3 48.6 80 Cu-ZnO-ZrO2[22] 3∶1 240 3.0 11.8 46.0 180 This work 3∶1 220 4.0 14.83 78.8 345.8
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表 3 催化性能
Table 3 Catalytic performance
Catalyst Molar ratio of elements GHSV/(cm3·g−1·h−1) t(℃)/p(MPa) Conv./% Sel./% Cu-ZrO2-55 Cu∶Zr=5∶3 9000 220/4.0 6.3 72.7 ZnO/Cu-ZrO2-55 Cu∶Zn∶Zr=5∶2∶3 9000 220/4.0 8.4 67.8 CZZ-55 Cu∶Zn∶Zr=5∶2∶3 9000 220/4.0 14.83 78.8 CZZ-220 Cu∶Zn∶Zr=5∶2∶3 9000 220/4.0 14.6 71.0 CZZ-CP Cu∶Zn∶Zr=5∶2∶3 9000 220/4.0 13.2 58.4 Note∶ 0.3 g catalyst is taken for each measurement; flow is controlled at 45 mL/min.
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[1] JIANG X, NIE X, GUO X, et al. Recent advances in carbon dioxide hydrogenation to methanol via heterogeneous catalysis[J]. Chem Rev,2020,120(15):7984−8034. doi: 10.1021/acs.chemrev.9b00723 [2] SEN R, GOEPPERT A, SURYA PRAKASH G K. Homogeneous hydrogenation of CO2 and CO to methanol: The renaissance of low‐temperature catalysis in the context of the methanol economy[J]. Angew Chem Int Ed,2022,61(42):e202207278. doi: 10.1002/anie.202207278 [3] ZHONG J, YANG X, WU Z, et al. State of the art and perspectives in heterogeneous catalysis of CO2 hydrogenation to methanol[J]. Chem Soc Rev,2020,49(5):1385−1413. doi: 10.1039/C9CS00614A [4] LIU Y, PAN Y, WANG H, et al. Ordered mesoporous Cu-ZnO-Al2O3 adsorbents for reactive adsorption desulfurization with enhanced sulfur saturation capacity[J]. Chin J Catal,2018,39(9):1543−1551. doi: 10.1016/S1872-2067(18)63085-2 [5] SONG L, WANG H, WANG S, et al. Dual-site activation of H2 over Cu/ZnAl2O4 boosting CO2 hydrogenation to methanol[J]. Appl Catal B: Environ,2023,322:122137. doi: 10.1016/j.apcatb.2022.122137 [6] TU W, REN P, LI Y, et al. Gas-dependent active sites on Cu/ZnO clusters for CH3OH synthesis[J]. J Am Chem Soc,2023,145(16):8751−8756. doi: 10.1021/jacs.2c13784 [7] ARENA F, BARBERA K, ITALIANO G, et al. Synthesis, characterization and activity pattern of Cu-ZnO/ZrO2 catalysts in the hydrogenation of carbon dioxide to methanol[J]. J Catal,2007,249(2):185−194. doi: 10.1016/j.jcat.2007.04.003 [8] GUO X, MAO D, LU G, et al. Glycine-nitrate combustion synthesis of CuO-ZnO-ZrO2 catalysts for methanol synthesis from CO2 hydrogenation[J]. J Catal,2010,271(2):178−185. doi: 10.1016/j.jcat.2010.01.009 [9] MUREDDU M, FERRARA F, PETTINAU A. Highly efficient CuO/ZnO/ZrO2@SBA-15 nanocatalysts for methanol synthesis from the catalytic hydrogenation of CO2[J]. Appl Catal B: Environ,2019,258:117941. doi: 10.1016/j.apcatb.2019.117941 [10] XU Y, GAO Z, PENG L, et al. A highly efficient Cu/ZnO x/ZrO2 catalyst for selective CO2 hydrogenation to methanol[J]. J Catal,2022,414:236−244. doi: 10.1016/j.jcat.2022.09.011 [11] YANG M, YU J, ZIMINA A, et al. Probing the nature of zinc in copper-zinc-zirconium catalysts by operando spectroscopies for CO2 hydrogenation to methanol[J]. Angew Chem Int Ed,2023,62(7):e202216803. doi: 10.1002/anie.202216803 [12] WANG Y, KATTEL S, GAO W, et al. Exploring the ternary interactions in Cu-ZnO-ZrO2 catalysts for efficient CO2 hydrogenation to methanol[J]. Nat Commun,2019,10(1):1166. doi: 10.1038/s41467-019-09072-6 [13] CHEN C, KOSARI M, XI S, et al. Optimizing the interfacial environment of triphasic ZnO-Cu-ZrO2 confined inside mesoporous silica spheres for enhancing CO2 hydrogenation to methanol[J]. ACS ES& T Eng,2023,3(5):638−650. [14] ZHANG C, YU D, PENG C, et al. Research progress on preparation of 3DOM-based oxide catalysts and their catalytic performances for the combustion of diesel soot particles[J]. Appl Catal B: Environ,2022,319:121946. doi: 10.1016/j.apcatb.2022.121946 [15] LI J, LI R, WANG W, et al. Ordered mesoporous crystalline frameworks toward promising energy applications [J]. Adv Mater, 2024, 2311460. [16] ZHENG Y, WANG L, LIU H, et al. A modular co‐assembly strategy for ordered mesoporous perovskite oxides with abundant surface active sites[J]. Angew Chem Int Ed,2022,61(37):e202209038. doi: 10.1002/anie.202209038 [17] BéJAR J, ÁLVAREZ-CONTRERAS L, LEDESMA-GARCíA J, et al. An advanced three-dimensionally ordered macroporous NiCo2O4 spinel as a bifunctional electrocatalyst for rechargeable Zn-air batteries[J]. J Mater Chem A,2020,8(17):8554−8565. doi: 10.1039/D0TA00874E [18] XIAO J, MAO D, GUO X, et al. Effect of TiO2, ZrO2, and TiO2-ZrO2 on the performance of CuO-ZnO catalyst for CO2 hydrogenation to methanol[J]. Appl Surf Sci,2015,338:146−153. doi: 10.1016/j.apsusc.2015.02.122 [19] FREI E, SCHAADT A, LUDWIG T, et al. The influence of the precipitation/ageing temperature on a Cu/ZnO/ZrO2 catalyst for methanol synthesis from H2 and CO2[J]. ChemCatChem,2014,6(6):1721−1730. doi: 10.1002/cctc.201300665 [20] BONURA G, CORDARO M, CANNILLA C, et al. The changing nature of the active site of Cu-Zn-Zr catalysts for the CO2 hydrogenation reaction to methanol[J]. Appl Catal B: Environ,2014,152−153:152−161. doi: 10.1016/j.apcatb.2014.01.035 [21] LI C, YUAN X, FUJIMOTO K. Development of highly stable catalyst for methanol synthesis from carbon dioxide[J]. Appl Catal A: Gen,2014,469:306−311. doi: 10.1016/j.apcata.2013.10.010 [22] BONURA G, ARENA F, MEZZATESTA G, et al. Role of the ceria promoter and carrier on the functionality of Cu-based catalysts in the CO2-to-methanol hydrogenation reaction[J]. Catal Today,2011,171(1):251−256. doi: 10.1016/j.cattod.2011.04.038 [23] WU J, SAITO M, TAKEUCHI M, et al. The stability of Cu/ZnO-based catalysts in methanol synthesis from a CO2-rich feed and from a CO-rich feed[J]. Appl Catal A: Gen,2001,218(1):235−240. [24] WANG F, CHEN F, GUO X, et al. Enhanced performance and stability of Cu/ZnO catalyst by hydrophobic treatment for low-temperature methanol synthesis from CO2[J]. Catal Today,2024,425:114344. doi: 10.1016/j.cattod.2023.114344 [25] BARROW N, BRADLEY J, CORRIE B, et al. Doubling the life of Cu/ZnO methanol synthesis catalysts via use of Si as a structural promoter to inhibit sintering[J]. Sci Adv,2024,10(3):eadk2081. doi: 10.1126/sciadv.adk2081 [26] JIANG L, LI K, PORTER W N, et al. Role of H2O in catalytic conversion of C1 molecules [J]. J Am Chem Soc, 2024, 10.1021/jacs. 3c13374. [27] 刘昊然, 于志庆, 黄文斌, 等. Ce改性对CuLDH催化CO2加氢制甲醇性能的影响 [J]. 燃料化学学报(中英文), 2023, 52 (2): 159−170.LIU Haoran, YU Zhiqing, HUANG Wenbin, et al. Effect of Ce modification on the performance of CuLDH catalyst for CO2 hydrogenation to methanol [J]. J Fuel Chem Technol, 2023, 52 (2): 159−170.) [28] GUO T, GUO Q, LI S, et al. Effect of surface basicity over the supported Cu-ZnO catalysts on hydrogenation of CO2 to methanol[J]. J Catal,2022,407:312−321. doi: 10.1016/j.jcat.2022.01.035 [29] 姜秀云, 杨文兵, 宋昊, 等. 甲酸辅助Cu-ZnO-Al2O3催化剂制备及其CO2加氢制甲醇性能研究[J]. 燃料化学学报(中英文),2023,51(1):120−128. doi: 10.1016/S1872-5813(22)60041-0JIANG Xiuyun, YANG Wenbing, SONG Hao, et al. Formic acid assisted synthesis of Cu-ZnO-Al2O3 catalyst and its performance in CO2 hydrogenation to methanol[J]. J Fuel Chem Technol,2023,51(1):120−128. doi: 10.1016/S1872-5813(22)60041-0 [30] KATTEL S, YAN B, YANG Y, et al. Optimizing binding energies of key intermediates for CO2 hydrogenation to methanol over oxide-supported copper[J]. J Am Chem Soc,2016,138(38):12440−12450. doi: 10.1021/jacs.6b05791 [31] RHODES M D, POKROVSKI K A, BELL A T. The effects of zirconia morphology on methanol synthesis from CO and H2 over Cu/ZrO2 catalysts: Part II. Transient-response infrared studies[J]. J Catal,2005,233(1):210−220. doi: 10.1016/j.jcat.2005.04.027 [32] 王世强, 杨金海, 赵宁, 等. 不同方法制备的Cu-Mn-La-Zr催化剂上二氧化碳加氢制甲醇反应机理研究[J]. 燃料化学学报(中英文),2023,51(7):970−976. doi: 10.1016/S1872-5813(22)60079-3WANG Shiqiang, YANG Jinhai, ZHAO Ning, et al. Mechanistic study on the hydrogenation of CO2 to methanol over Cu-Mn-La-Zr catalysts prepared by different methods[J]. J Fuel Chem Technol,2023,51(7):970−976. doi: 10.1016/S1872-5813(22)60079-3 [33] YANG R, ZHANG Y, IWAMA Y, et al. Mechanistic study of a new low-temperature methanol synthesis on Cu/MgO catalysts[J]. Appl Catal A: Gen,2005,288(1):126−133. [34] SUN Q, LIU C-W, PAN W, et al. In situ IR studies on the mechanism of methanol synthesis over an ultrafine Cu/ZnO/Al2O3 catalyst[J]. Appl Catal A: Gen,1998,171(2):301−308. doi: 10.1016/S0926-860X(98)00096-9 [35] WANG Y, GAO W, LI K, et al. Strong evidence of the role of H2O in affecting methanol selectivity from CO2 hydrogenation over Cu-ZnO-ZrO2[J]. Chem,2020,6(2):419−430. doi: 10.1016/j.chempr.2019.10.023 [36] DU H, WILLIAMS C T, EBNER A D, et al. In situ FTIR spectroscopic analysis of carbonate transformations during adsorption and desorption of CO2 in K-promoted HTlc[J]. Chem Mater,2010,22(11):3519−3526. doi: 10.1021/cm100703e [37] FENG Z, TANG C, ZHANG P, et al. Asymmetric sites on the ZnZrO x catalyst for promoting formate formation and transformation in CO2 hydrogenation[J]. J Am Chem Soc,2023,145(23):12663−12672. doi: 10.1021/jacs.3c02248 [38] MEUNIER F C, DANSETTE I, PAREDES‐NUNEZ A, et al. Cu‐bound formates are main reaction intermediates during CO2 hydrogenation to methanol over Cu/ZrO2[J]. Angew Chem Int Ed,2023,62(29):e202303939. doi: 10.1002/anie.202303939 [39] WU W, WANG Y, LUO L, et al. CO2 hydrogenation over copper/ZnO single-atom catalysts: Water-promoted transient synthesis of methanol[J]. Angew Chem Int Ed,2022,61(48):e202213024. doi: 10.1002/anie.202213024 -
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