Iron-silica nanocomposites as a catalyst for the selective conversion of syngas to light olefins
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摘要: 分别采用一步合成法和常规共沉淀法制备了Fe/SiO2催化剂,通过N2物理吸附、X射线衍射、透射电镜、傅里叶变换红外光谱和程序升温还原等方法对催化剂进行了表征,并在固定床反应器中对其费托合成制低碳烯烃的催化性能进行了评价。结果表明,与共沉淀铁基催化剂不同,采用一步合成法制备的纳米复合物主要由Fe3O4相构成,形貌呈规则球形,平均粒径为30 nm,尺寸分布窄,更容易还原。一步合成法制得的Fe/SiO2催化剂对费托合成反应具有较高的活性和低碳烯烃选择性、较低的甲烷选择性和良好的稳定性。Abstract: A series of Fe/SiO2 catalysts were prepared by one-pot synthesis and conventional co-precipitation methods; they were characterized by N2 physisorption, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and temperature-programmed reduction. The performances of the Fe/SiO2 catalysts in Fischer-Tropsch synthesis (FTS) were evaluated in a fixed-bed reactor for the production of light olefins from syngas. The results showed that in the Fe/SiO2 catalyst prepared by one-pot synthesis method, the iron oxide is present as iron-silica nanocomposite in the form of Fe3O4 (magnetite). Compared with the catalyst prepared by conventional co-precipitation method, the magnetite-silica nanocomposite by one-pot synthesis exhibits a more uniform spherical-like morphology, narrower size distribution (30 nm in average) and better reducibility. In FTS, the Fe/SiO2 catalyst prepared by one-pot synthesis method exhibits higher activity and selectivity to light olefin as well as lower selectivity to methane and better stability.
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Key words:
- syngas /
- Fischer-Tropsch synthesis /
- light olefins /
- magnetite /
- nanocomposites
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杨学萍, 董丽. 合成气直接制低碳烯烃技术进展与经济性分析[J]. 化工进展, 2012, 31(8): 1726-1731. (YANG Xue-ping, DONG Li. Technical progress and economical ananysis on the direct production of light olefins from syngas[J]. Chemical Industry and Engineering Progress, 2012, 31(8): 1726-1731.) TORRES GALVIS H M, DE JONG K P. Catalysts for production of lower olefins from synthesis gas[J]. ACS Catal, 2013, 3(9): 2130-2149. DE SMIT E, WECKHUYSEN B M. The renaissance of iron-based Fischer-Tropsch synthesis: On the multifaceted catalyst deactivation behaviour[J]. Chem Soc Rev, 2008, 37(12): 2758-2781. ABELLO S, MONTANE D. Exploring iron-based multifunctional catalysts for Fischer-Tropsch synthesis[J]. ChemSusChem, 2011, 4(11): 1538-1556. MCDONALD M A, STORM D, BOUDART M. Hydrocarbon synthesis from CO-H2 on supported iron: Effect of particle size and interstitials[J]. J Catal, 1986, 102(2): 386-400. BOUDART M, MCDONALD M A. Structure sensitivity of hydrocarbon synthesis from carbon monoxide and hydrogen[J]. J Phys Chem, 1984, 88(11): 2185-2195. DEN BREEJEN J P, SIETSMA J R A, FRIEDRICH H, BITTER J H, DE JONG K P. Design of supported cobalt catalysts with maximum activity for the Fischer-Tropsch synthesis[J]. J Catal, 2010, 270(1): 146-152. 马利海, 张建利, 范素兵, 赵天生. 水热法Fe-Mn催化剂制备及其合成气制低碳烯烃催化活性[J]. 燃料化学学报, 2013, 41(11): 1356-1360. (MA Li-hai, ZHANG Jian-li, FAN Su-bing, ZHAO Tian-sheng. Preparation of Fe-Mn catalyst by hydrothermal methodand its catalytic activity for the synthesis of light olefins from CO hydrogenation[J]. Journal of Fuel Chemistry and Technology, 2013, 41(11): 1356-1360.) KANG S H, BAE J W, SAI PRASAD P S, PARK S J, WOO K J, JUN K W. Effect of preparation method of Fe-based Fischer-Tropsch catalyst on their light olefin production[J]. Catal Lett, 2009, 130(3/4): 630-636. LAURENT S, FORGE D, PORT M, ROCH A, ROBIC C, VANDER ELST L, MULLER R N. Magnetic iron oxide nanoparticles: Synthesis, stabilization, vectorization, physicochemical characterizations, and biological applications[J]. Chem Rev, 2008, 108(6): 2064-2110. GOLE A, STONE J W, GEMMILL W R, ZUR LOYE H C, MURPHY C J. Iron oxide coated gold nanorods: Synthesis, characterization, and magnetic manipulation[J]. Langmuir, 2008, 24(12): 6232-6237. XIONG Y, YE J, GU X, CHEN Q W. Synthesis and assembly of magnetite nanocubes into flux-closure rings[J]. J Phys Chem C, 2007, 111(19): 6998-7003. RODULFO-BAECHLER S M, GONZÁ LEZ-CORTÉS S L, OROZCO J, SAGREDO V, FONTAL B, MORA A J, DELGADO G. Characterization of modified iron catalysts by X-ray diffraction, infrared spectroscopy, magnetic susceptibility and thermogravimetric analysis[J]. Mater Lett, 2004, 58(20): 2447-2450. ZHANG C H, WAN H J, YANG Y, XIANG H W, LI Y W. Study on the iron-silica interaction of a co-precipitated Fe/SiO2 Fischer-Tropsch synthesis catalyst[J]. Catal Commun, 2006, 7(9):733-738. SUO H Y, WANG S G, ZHANG C H, XU J, WU B S, YANG Y, XIANG H W, LI Y W. Chemical and structural effects of silica in iron-based Fischer-Tropsch synthesis catalysts[J]. J Catal, 2012, 286: 111-123. JOZWIAK W K, KACZMAREK E, MANIECKI T P, IGNACZAK W, MANIUKIEWICZ W. Reduction behavior of iron oxides in hydrogen and carbon monoxide atmospheres[J]. Appl Catal A: Gen, 2007, 326(1): 17-27. REDL F X, BLACK C T, PAPAEFTHYMIOU G C, SANDSTROM R L, YIN M, ZENG H, MURRAY C B, O'BRIEN S P. Magnetic, electronic, and structural characterization of nonstoichiometric iron oxides at the nanoscale[J]. J Am Chem Soc, 2004, 126(44): 14583-14599. WAN H J, WU B S, ZHANG C H, XIANG H W, LI Y W. Promotional effects of Cu and K on precipitated iron-based catalysts for Fischer-Tropsch synthesis[J]. J Mol Catal A: Chem, 2008, 283(1/2): 33-42. 沈菊李, 刘化章, 李小年, 胡樟能, 国海光, 张天明. 费-托合成Fe1-xO基熔铁催化剂的研究[J]. 催化学报, 2004, 25(10): 785-788. (SHEN Ju-li, LIU Hua-zhang, LI Xiao-nian, HU Zhang-neng, GUO Hai-guang, ZHANG Tian-ming. Study on Fe1-xO-based fused iron catalyst for Fischer-Tropsch synthesis[J]. Chinese Journal of Catalysis, 2004, 25(10): 785-788.)
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