中文摘要：

探讨了MnOx助剂对Fe/SiO2催化剂经由费-托反应（Fischer-Tropsch）制备低碳烯烃（FTO）的影响。通过浸渍法制备了Fe20/SiO2和Fe20-Mn1.0/SiO2催化剂,结果表明MnOx助剂显著提升了CO转化率和C2～C4烯烃的时空收率。程序升温吸附实验表明MnOx助剂增加了Fe基催化剂表面碱性,促进了CO的解离吸附。运用幂指数模型,研究了Fe20/SiO2和Fe20-Mn1.0/SiO2催化剂上FTO反应动力学,得到了各产物生成活化能与H2/CO反应级数。最后,结合动力学研究与程序升温表征结果,对Fe基催化剂FTO反应机理,尤其是MnOx助剂提高Fe20/SiO2催化剂上低碳烯烃选择性的作用进行了讨论。

英文摘要：

The promotional effects of MnOx on the synthesis of lower olefins via Fischer-Tropsch reaction over Fe/SiO2 catalysts were investigated. It was found that CO conversion and STY（space time yield） of C2-C4 olefins was greatly enhanced with the addition of MnOx. CO2-TPD and CO-TPD （temperature program desorption） have evidenced that MnOx could enhance the surface basicity of Fe-based catalyst. The intrinsic kinetics for Fischer-Tropschto reaction to lower olefins （FTO） was measured under the realistic reaction conditions over Fe/SiO2 catalysts with and without MnOx by fitting power-law model. The apparent activation energies and reaction orders were calculated based on the formation of products and CO conversion. With combination of kinetics and temperature-programmed techniques, it was found that the MnOx promoter can enhance the dissociation of CO and inhibite the readsorption of lower olefins, leading to the enhancement of STY and the selectivity to lower olefins. Finally, the FTO reaction mechanisms of Fe-based catalysts, especially, the promotional effects of MnOx on Fe/SiO2 for the production of lower olefins, were speculated.