碳化对超细Fe-Mn催化剂亮 CO加氢反应行为的影响

摘要

以超细Fe-Mn催化剂为前驱体,对其进行了CH4/H2气氛下的高温碳化及反应行为研究.结果表明,高温碳化后,催化剂比表面积明显降低,主要物相结构为FeO-MnO尖晶石和α-Fe相,并有大量碳化铁微晶生成.在CO加氢反应中,碳化过程明显提高了烯烃选择性,降低了CH4选择性,促进了链增长.结果认为,碳化过程改变了催化剂表面化学性质,增强了表面碱性,抑制了二次加氧反应,提高了烯烃选择性.%The effect of high temperature carburization on the catalytic performances over an ultrafine Fe-Mn catalyst was investigated. The surface area of the catalyst distinctly decreased after carburization. The carburization process favored the formation of FeO-MnO spinel phase and α-Fe, and small iron carbide crystallite was also formed. The catalyst after carburization exhibited high light olefin selectivity and low methane selectivity during CO hydrogenation, also, the chain propagation ability was promoted. The characterization of the catalyst indicated that the surface properties of the catalyst after carburization were improved. The carburization process enhanced the basicity of the catalyst and suppressed the secondary reactions of hydrogenation, and resulted in high selectivity to light olefins.