CuFe(100)及(110)面上合成气制低碳醇碳链增长机理研究  

Carbon Chain Growth Mechanism of Higher Alcohols Formation from Syngas on CuFe(100)and(110)

作　　者：王康明 张海涛[1] 李涛[1] WANG Kangming;ZHANG Haitao;LI Tao(Engineering Research Center of the Large Scale Reactor Engineering and Technology,Ministry of Education,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]华东理工大学大型工业反应器工程教育部工程研究中心,上海200237

出　　处：《华东理工大学学报（自然科学版）》2022年第2期139-147,共9页Journal of East China University of Science and Technology

摘　　要：CuFe混合催化剂是一种重要的合成气制低碳醇用催化剂。为深入了解合成气制低碳醇的反应机理,从量子尺度利用密度泛函理论(DFT)研究了CuFe混合催化剂两个主要表面(100)及(110)上的碳链增长机理。计算发现Cu在Fe(100)及Fe(110)面上倾向于单层聚集分布,CuFe(100)面上CO活化机理为H辅助CO生成CHO,随后逐步加氢生成CH2O和CH_(3)O,CH_(3)O更倾向于生成CH_(3)OH,其碳链增长方式为CHO插入;CuFe(110)面上CO活化机理与(100)面上相同,H辅助CO加氢生成CHO,并不断加氢依次生成CH2O和CH_(3)O,但CH_(3)O更倾向于生成CH_(3),CH_(3)进一步与CO耦合完成碳链的增长。CuFe catalyst is an important catalyst for higher alcohols formation from syngas.In order to gain mechanistic insight into the reaction,spin-polarized density functional theory calculations were performed to investigate the growth mechanism of carbon chains on CuFe(100)and(110)surfaces.The calculated results show that Cu atoms prefer to aggregate rather than homogeneously disperse on the Fe(100)and(110)surfaces.With the increase of Cu atoms,the surface energy decreases gradually,suggesting that the surface tends to be more stable.The dominant activation mechanism of CO on CuFe(100)surfaces is ascribed to a H-assisted CO dissociation via CHO intermediate,which is then progressively hydrogenated to form CH_(2)O and CH_(3)O.Subsequently,CH_(3)O is dominantly hydrogenated to form CH_(3)OH.The pathway of carbon chain growth is found to be CHO rather than CO insertion.The activation mechanism of CO on CuFe(110)surface is found to be similar to that on CuFe(100)surface.The pathway of CH_(3)O formation is CO+3H→CHO+2H→CH_(2)O+H→CH_(3)O.On the CuFe(110)surface,CH_(3)formation is more thermodynamically favorable than CH_(3)OH,which leads to the production of more CH_(3)for CO insertion to form C^(2+)higher alcohols.This research offers mechanistic insight into improving the production of higher alcohols on CuFe catalyst.

关 键 词：CuFe 合成气 低碳醇 碳链增长 DFT 

分 类 号：TQ032.4[化学工程]