文献类型：期刊文献

英文题名：Revealing the Effect of Sodium on Iron-Based Catalysts for CO2 Hydrogenation: Insights from Calculation and Experiment

作者：Liu, Xianglin[1];Zhang, Chao[1];Tian, Pengfei[2];Xu, Minjie[1];Cao, Chenxi[1];Yang, Zixu[1];Zhu, Minghui[1];Xu, Jing[1]

机构：[1]East China Univ Sci & Technol, Sch Chem Engn, State Key Lab Chem Engn, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Sch Mech & Power Engn, Shanghai 200237, Peoples R China

年份：2021

卷号：125

期号：14

起止页码：7637

外文期刊名：JOURNAL OF PHYSICAL CHEMISTRY C

收录：;EI(收录号：20211810291643);WOS:【SCI-EXPANDED(收录号:WOS:000641307100012)】；

基金：This work was supported by the National Science Foundation (21878080 and 21808058), Shanghai Sailing Program (19YF1411000), China Postdoctoral Science Foundation (2018M641034) and Ningxia Science Foundation (2019AAC03282).

语种：英文

外文关键词：Binding energy - Carbon dioxide - Catalysis - Catalyst selectivity - Density functional theory - Design for testability - Electronic structure - Hydrogenation - Iron - Iron compounds - Sodium

摘要：The promotional effects of sodium on Fe5C2 catalysts for CO2 hydrogenation were systematically investigated by a synergistic combination of density functional theory (DFT) calculations and experimental methods. Na was found to markedly alter the electronic structure of Fe5C2 surface, leading to a reduction of the CO2 dissociation barrier from 0.45 to 0.08 eV and a decrease of the hydrogen binding energy. Moreover, Na lowers methane's selectivity by hindering further hydrogenation of CH2 and enhances C-C coupling probability by promoting the chain growth of CH2. Additionally, Na strengthens alkenes' selectivity by facilitating dehydrogenation of alkyls and boosting the desorption of alkenes. The theoretical findings were confirmed by experimental results. Adding Na to Fe5C2 catalyst was found to facilitate CO2 conversion and alkenes' selectivity. Especially, the O/P (olefin/paraffin) ratio of C-2-C-4 hydrocarbons increases from 2.0 to 9.7 and the C5+ hydrocarbons' selectivity increases from 12.6% to 51.8%. This study further deepens the understanding of the promotional effect of sodium on Fe-based catalysts for CO2 hydrogenation and enlightens the rational design of highly selective catalysts.