文献类型：期刊文献

英文题名：Highly selective production of heavy hydrocarbons over cobalt-graphene-silica nanocomposite catalysts

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

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

年份：2017

卷号：7

期号：53

起止页码：33441

外文期刊名：RSC ADVANCES

收录：;EI(收录号：20172803931079);WOS:【SCI-EXPANDED(收录号:WOS:000404864100047)】；

基金：We gratefully acknowledge the financial support of 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：Cobalt compounds - Fischer-Tropsch synthesis - Sol-gels - Nanocatalysts - Chemical reactors - Sol-gel process - Catalyst activity - Catalyst selectivity - Silica - Hydrocarbons - Nanocomposites

摘要：Herein, cobalt-graphene-silica nanocomposites were prepared by a sol-gel method to produce heavy hydrocarbons for Fischer-Tropsch synthesis. The catalysts were characterized by N-2 physisorption, XRD, TEM, TPR, TPD, XPS, and DRIFTS techniques. The activity of catalysts and the selectivity of products were examined in a tubular fixed-bed reactor. It can be concluded that the introduction of graphene into cobalt-silica nanocomposites significantly enhanced the amount and stability of adsorbed CO at low temperatures, resulting in higher concentrations of CO species on the catalyst surface. Moreover, graphene can weaken the cobalt-silica interaction, leading to higher degree of reduction of cobalt oxides and higher adsorption amounts of H-2. In addition, the introduction of graphene led to the formation of cobalt with smaller particle sizes, which contributed to great enhancement of CO conversion. The selectivity to methane distinctly decreased to 4.2% from 8.1%, whereas the selectivity to C-5(+) products increased from 84.5% to 92.4%. The a value increased from 0.89 for the Co-Si catalyst to 0.94 for the Co-0.1GSi catalyst. In addition, with the increase in the graphene content, the fraction of heavy hydrocarbons (C19-29) for catalysts evidently increased to 36.0% from 28.3%, but the fraction of naphtha (C5-12) clearly reduced to 17.7% from 27.7%.