文献类型：期刊文献

英文题名：Effect of alkalis (Li, Na, and K) on precipitated iron-based catalysts for high-temperature Fischer-Tropsch synthesis

作者：Yang, Yi[1];Zhang, Haitao[1];Ma, Hongfang[1];Qian, Weixin[1,3];Sun, Qiwen[2];Ying, Weiyong[1]

机构：[1]East China Univ Sci & Technol, Engn Res Ctr Large Scale Reactor Engn & Technol, Sch Chem Engn, State Key Lab Chem Engn,Minist Educ, Shanghai 200237, Peoples R China;[2]State Key Lab Coal Liquefact & Coal Chem Technol, Shanghai 201203, Peoples R China;[3]East China Univ Sci & Technol, Room 303,16th Res Bldg, Shanghai 200237, Peoples R China

年份：2022

卷号：326

外文期刊名：FUEL

收录：;EI(收录号：20222712317118);WOS:【SCI-EXPANDED(收录号:WOS:000824643800005)】；

基金：We gratefully acknowledge the 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. JKA01211710) .

语种：英文

外文关键词：Fischer-Tropsch synthesis; Light olefins; Alkali metals; Iron carbides; Iron-based catalyst

摘要：Alkalis (Li, Na, and K) decorated FeMnZr catalysts prepared by coprecipitation and impregnation methods were used to investigate the effects of three alkali metal promoters and promoter loading (for Na and K) on the ironbased catalyst for high-temperature Fischer-Tropsch synthesis (HTFT). The results showed that alkalis donated electrons to iron species, which promoted CO dissociative adsorption while suppressing hydrogen adsorption, then boosted the selectivity to light olefins and the improvement was enhanced with the increase of the atomic number of alkali metals and the content of alkali metals. Moreover, compared to alkalis-free catalysts, alkalispromoted catalysts facilitated the formation of x-Fe5C2 and e'-Fe2.2C. In alkalis decorated catalysts, the x-Fe5C2 content decreased and the e'-Fe2.2C content increased with increasing basicity of the catalyst surface. In addition, compared with x-Fe5C2, e'-Fe2.2C has a stronger C-C coupling ability and promotes chain growth more. Compared to Li and Na promoters, K was easier to facilitate the formation of e'-Fe2.2C due to its strongest basicity and CO dissociative adsorption ability. The lowest CH4 and highest C5+ selectivity were accompanied by the highest content of e'-Fe2.2C on K-promoted catalysts, which suggested that e'-Fe2.2C had outstanding C-C coupling ability.