DFT study of CO_(2)electrochemical reduction on two-dimensional metal-based covalent organic frameworks

二维金属基共价有机骨架催化CO_(2)电化学还原的DFT研究

CO_(2)electrochemical reduction(CO_(2)ER)to high-value fuels and chemicals is a promising strategy for using CO_(2)as a carbon source.However,the large-scale application of CO_(2)ER is limited by the lack of efficient and selective electrocatalysts.By means of density functional theory(DFT)calculations,the potential of transitional metal-based covalent organic frameworks(TM-COFs,TM=Fe,Co,Ni,Cu,Zn,Ru,Rh,Pd,and Ag)as CO_(2)reduction electrocatalysts was systematically studied.The results show that the single TM atom can be firmly anchored on COFs for forming stable single-atom catalysts.The TM atom in phthalocyanine has excellent catalytic activity towards CO_(2)ER,while the pyridine N in pyrazine is the active site of the hydrogen evolution reaction(HER).Among studied candidates,Co-COF and Rh-COF are predicted to have limiting potential of-0.66/-0.11 and-0.49/-0.49 V for CO_(2)ER/HER,respectively.The present study may provide a new strategy for designing novel bifunctional catalysts.

利用电催化二氧化碳还原(CO_(2)ER)将CO_(2)转化为高附加价值燃料和化学品是一种有前途的策略。然而,由于缺乏高效和选择性的电催化剂,限制了CO_(2)ER的大规模应用。采用密度泛函理论(DFT)计算,系统研究了过渡金属基共价有机骨架(TM-COFs,TM=Fe,Co,Ni,Cu,Zn,Ru,Rh,Pd和Ag)作为CO_(2)还原电催化剂的潜力。结果表明,单个TM原子可以锚定在COFs上形成稳定的单原子催化剂。酞菁中的TM原子对CO_(2)ER具有优异的催化活性,而吡嗪中的吡啶N原子是析氢反应(HER)的活性位点。在所研究的材料中,Co-COF和Rh-COF对CO_(2)ER/HER的极限电位分别为-0.66/-0.11和-0.49/-0.49 V。本研究为设计新型双功能催化剂提供了新的思路。