文献类型：期刊文献

英文题名：In situ investigation on Co-phase evolution and its performance for Fischer-Tropsch synthesis over Nb-promoted cobalt catalysts

作者：Huang, Jian[1];Qian, Weixin[1];Zhang, Haitao[1];Ying, Weiyong[1]

机构：[1]East China Univ Sci & Technol, Engn Res Ctr Large Scale Reactor Engn & Technol, State Key Lab Chem Engn, Minist Educ, Shanghai 200237, Peoples R China

年份：2017

卷号：7

期号：23

起止页码：5530

外文期刊名：CATALYSIS SCIENCE & TECHNOLOGY

收录：;EI(收录号：20174904504071);WOS:【SCI-EXPANDED(收录号:WOS:000417706600008)】；

基金：We gratefully acknowledge financial support from the National High Technology Research and Development Plan of China (863 plan, 2011AA05A204) and the Fundamental Research Funds for the Central Universities (No: 222201717013).

语种：英文

外文关键词：Fischer-Tropsch synthesis - Cobalt - Chemical reactors - Indium compounds - X ray photoelectron spectroscopy - Catalysts

摘要：Nb-promoted cobalt catalysts were prepared by the incipient wetness impregnation method and characterized by ex/in situ XRD, in situ DRIFTS, N-2 physisorption, TEM, EDS-mapping, H-2-TPR, CO/H-2-TPD, and XPS. Their performance was investigated in a fixed bed reactor for Fischer-Tropsch synthesis (FTS). As regards the sample texture, niobium oxide (NbOx) can obviously reduce the BET surface area and pore volume, and promote the formation of uniform cobalt particles with a smaller size. The presence of NbOx complexes can weaken the metal-support interaction, while it also makes Co3O4 species easily reducible to metallic cobalt and favours the formation of a hexagonal close-packed cobalt phase, as confirmed by the results of H-2-TPR and ex/in situ XRD. What's more, NbOx can enhance the adsorption stability and the amount of CO adsorbed under approximately actual FTS reaction conditions, as verified by the results of CO-TPD. In addition, NbOx complexes can be considered as weak electron donors, as confirmed by the results of XPS, leading to a higher concentration of surface carbon species. According to the performance results, the selectivity to C-5(+) products increased to 89.3% from 85.6% and the CO conversion was significantly increased to 94.1% from 70.7% with the increase of Nb loading to 1.57 wt% from zero. It is found that highly selective production of heavy hydrocarbons can be achieved at a higher activity level over Nb-promoted cobalt catalysts.