双原子位点M-N-C电催化剂在CO_(2)还原反应中活性位点的最佳分布

Optimal Distribution of Active Sites of CO_(2) Reduction Reaction Catalyzed by Diatomic Site M-N-C

双原子位点M-N-C催化剂是催化CO_(2)还原反应(CO_(2)RR)性能最佳的催化剂之一.然而,目前的研究主要集中于M-N-C活性中心原子类型的调控,低估了活性位点的配位模式及分布对其催化性能的影响.本文选取典型的双原子位点M-N-C催化剂(NiFe-N-C)为研究对象,采用密度泛函理论方法探究了9种活性位点具有不同配位环境的NiFe-N-C催化剂电催化CO_(2)RR的反应机理.结果表明,随着金属原子配位数、双原子位点间距离的增加,M-N-C催化剂的稳定性、催化CO_(2)还原至CO的活性及抑制氢析出反应的选择性均呈现先升高后下降的趋势.其中,金属原子四配位且对称分布的NiFe-N-C-model 3催化剂,因其双原子位点的强相互作用表现出最优的催化性能.

The diatomic site M-N-C catalysts are one of the best catalysts for CO_(2) reduction reaction(CO_(2)RR).However,the current researches mainly focus on the regulation of the atom type of the active center of M-N-C,and underestimate the effect of the coordination environment and distribution of the active sites on their catalytic performance.A typical diatomic site M-N-C catalyst(NiFe-N-C)was selected as the research object,and the electrocatalytic CO_(2)RR reaction mechanism of nine types of NiFe-N-C catalysts with different coordination environments at active sites were systematically investigated by the density functional theory(DFT)method.The results show that with the increase of the coordination number of metal atoms and the distance between diatomic sites,the stability of M-N-C catalysts,the catalytic activity of CO_(2) reduction to CO,and the selectivity of inhibiting hydrogen evolution reaction all show a trend of increasing first and then decreasing.Among them,the NiFe-N-C-model 3 catalyst with four-coordinated and symmetrically distributed metal atoms exhibits the best catalytic performance due to the strong interaction of the diatomic sites.This study provides theoretical support for the precise regulation of active sites in diatomic site M-N-C catalysts and the rational design of CO_(2)RR catalysts.