调节铜催化剂表面分子亲电性以调控电催化二氧化碳还原选择性  

Tuning molecular electrophilicity on Cu catalysts to steer CO_(2) electroreduction selectivity

作　　者：周贤龙 单洁琼 郑敏 李欢 夏宝玉 郑尧 Xianlong Zhou;Jieqiong Shan;Min Zheng;Huan Li;Bao-Yu Xia;Yao Zheng(School of Chemical Engineering and Advanced Materials,The University of Adelaide,Adelaide,SA 5005,Australia;Key Laboratory of Material Chemistry for Energy Conversion and Storage(Ministry of Education),Hubei Key Laboratory of Material Chemistry and Service Failure,National Laboratory for Optoelectronics,School of Chemistry and Chemical Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;Jiangsu Co-Innovation Centre of Efficient Processing and Utilization of Forest Resources,College of Chemical Engineering,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]School of Chemical Engineering and Advanced Materials,The University of Adelaide,Adelaide,SA 5005,Australia [2]Key Laboratory of Material Chemistry for Energy Conversion and Storage(Ministry of Education),Hubei Key Laboratory of Material Chemistry and Service Failure,National Laboratory for Optoelectronics,School of Chemistry and Chemical Engineering,Huazhong University of Science and Technology,Wuhan 430074,China [3]Jiangsu Co-Innovation Centre of Efficient Processing and Utilization of Forest Resources,College of Chemical Engineering,Nanjing Forestry University,Nanjing 210037,China

出　　处：《Science China Materials》2024年第6期1858-1865,共8页中国科学（材料科学）（英文版）

基　　金：supported by the Australian Research Council through the Discovery Project programs (FL170100154,FT200100062,DP220102596 and DP190103472);the support from the Australian Government through the Research Training Program Scholarships。

摘　　要：Cu是唯一能选择性将二氧化碳电还原(CRR)为多碳产物的过渡金属.然而,调控Cu的CRR选择性获得多种产物仍非常具有挑战性.本文选择了一系列具有不同亲电性的分子来修饰Cu催化剂以调控其CRR选择性,从而产生CH_(4)或C_(2)H_(4).理论计算表明,分子的亲电性决定催化反应中的质子活度,进而能促进或抑制CRR中的质子耦合电子转移(PCET)过程.实验发现,低亲电性分子(如1,2-双(4-吡啶基)乙烷)可以促进质子转移,加快^(*)CO中间体氢化过程而生成CH_(4),实现58.2%的法拉第效率;而高亲电性分子(如顺-1,2-双(4-吡啶基)乙烯)能构建强的氢键以稳定^(*)CO中间体,促进其偶联生成C_(2)H_(4),实现65.9%的法拉第效率.理论计算结合原位光谱表征揭示,分子亲电性可调节催化剂质子活度,影响CRR反应中^(*)CO氢化或偶联,进而调控CRR选择性.不同于常规的催化剂结构工程,本策略通过调节CRR中的PCET过程来调控选择性,为CRR的发展提供了新的认识.Cu is the only transition metal that can achieve electrochemical CO_(2) reduction(CRR)with the generation of hydrocarbons and oxygenates.However,it is still challenging to regulate CRR selectivity in a broad product distribution on Cu.Here,we selected a series of molecules with varying elec-trophilicity to modify Cu catalysts that achieve a high CRR selectivity towards either CH_(4) or C_(2)H_(4).Theoretical analysis shows that molecular electrophilicity determines catalyst’s proton availability,which promotes or inhibits the critical proton-coupled electron transfer(PCET)process in CRR.Consequently,the molecule with low electrophilicity(e.g.,1,2-bis(4-pyridyl)ethane)can facilitate proton transfer to hydro-genate^(*)CO intermediates to generate CH_(4) with a Faradaic efficiency(FE)of 58.2%,while the molecule with high elec-trophilicity(e.g.,trans-1,2-bis(4-pyridyl)ethylene)can build stronger hydrogen bonds to stabilize^(*)CO for further dimer-ization,realizing an FE of 65.9%for C_(2)H_(4).The combination of theoretical computation and in situ spectroscopic character-izations reveal that using molecular electrophilicity can tune catalyst’s proton availability,thereby altering its CRR pathway of either^(*)CO hydrogenation or^(*)CO-^(*)CO dimerization.This work provides new understanding of CRR selectivity by tuning the PCET process instead of materials engineering.

关 键 词：molecular electrophilicity Cu catalysts proton transfer CO_(2)electroreduction C1/C2 selectivity 

分 类 号：X701[环境科学与工程—环境工程] TQ426[化学工程]