In-ZrO2双金属氧化物用于合成气制芳烃

Indium modified zirconia coupling with HZSM-5 for syngas conversion to aromatics

  • 摘要: 金属氧化物-分子筛(OX-ZEO)双功能催化剂具有优异的芳烃选择性和催化剂使用寿命,但是其较低的CO转化率限制了该类型催化剂的进一步发展。采用水热法制备了In-Zr双金属氧化物,In/Zr物质的量比为1/100−1/1,通过XRD、TEM、N2-物理吸脱附等手段对样品相态、形貌进行研究;通过Py-FTIR、NH3-TPD、XPS、EPR等手段对样品表面性质进行探索,发现In的引入显著改变了催化剂的理化性能,进而导致催化性能的不同:In的引入有利于H2的活化、进而促进CO转化,同时伴随产生大量的CH4,In/Zr = 1/50具有18.2%的CO转化率和86.4%的含氧化合物选择性。与分子筛耦合后得到的双功能催化剂In/Zr = 1/50&H-ZSM-5展现出46.5%的CO转化率和62.6%的 \rmC_5+ 选择性,这其中含有93.4%的芳烃,但是,由于In在反应过程烧结,该双功能催化剂出现失活现象。

     

    Abstract: Metal oxide-zeolite (OX-ZEO) bifunctional catalysts have been shown to have excellent aromatic selectivity and catalytic stability in syngas conversion; however, low CO conversion hinders their further development. In this paper, a series of In-ZrO2 bi-metallic oxides with In/Zr molar ratio ranging of 1/100−1/1 were prepared. After thoroughly investigated by X-ray diffraction, transmission electron microscopy, N2 sorption, pyridine-adsorbed infrared spectroscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance and temperature programmed desorption technologies, we found that introduction of indium has significantly influence on the catalytic performance due to the variation of sample’s physicochemical properties. Indium species was benefit to the dissociation of H2 that promotes CO activation. Nevertheless, it also induced the formation of more CH4. In-ZrO2 oxide with In/Zr ratio of 1/50 showed CO conversion of 18.2% with the selectivity of oxygenates of 86.4%. After combined with H-ZSM-5, In/Zr=1/50&H-ZSM-5 gave CO conversion of 46.5% with \rmC_5+ selectivity of 62.6% and the aromatic selectivity in \rmC_5+ reached 93.4%. However, the catalytic stability of this bifunctional catalyst was gradually decreased due to the aggregation of indium atoms.

     

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