单原子配位结构及与载体相互作用的调控用于二氧化碳电催化还原

Tuning the Coordination Structure of Single Atoms and Their Interaction with the Support for Carbon Dioxide Electroreduction

电催化二氧化碳还原(ECR)制备高值化学品被认为是在碳中和背景下实现可再生能源存储及降低CO浓度的一种有效策略。为了实现此目标,催化剂的开发与设计是ECR研究的关键。单原子催化剂(SACs)因其独特的电子结构、明确的配位环境和极高的原子利用率,近年来在ECR领域引起了广泛关注。通过调节SACs的中心金属元素种类和局部配位结构,可有效调节SACs对CO和其还原中间体的吸附强度和催化活性。本文总结了SACs在ECR领域所取得的最新研究进展,重点讨论了SACs的配位结构及其与载体之间的相互作用对催化活性的影响以及相关调控策略,最后,提出了SACs应用于ECR所面临的机遇与挑战。

The combustion of fossil fuels increases atmospheric carbon dioxide(CO)concentrations,leading to adverse impacts on the planetary radiation balance and,consequently,on the climate.Fossil fuel utilization has contributed to a marked rise in global temperatures,now at least 1.2°C above‘pre-industrial’levels.To meet the 2015 Paris Agreement target of 1.5°C above pre-industrial levels,considerable efforts are required to efficiently capture and utilize CO.Among the different strategies developed for converting CO,electrochemical COreduction(ECR)to valuable chemicals using renewable energy is expected to revolutionize the manufacture of sustainable“green”chemicals,thereby achieving a closed anthropogenic carbon cycle.However,COis a thermodynamically stable and kinetically inert molecule that requires high electrical energy to bend the linear O=C=O bond by attacking the C atom.To facilitate the ECR with good energy efficiency,it is essential to lower the reaction overpotential as well as maintain a high current density and desirable product selectivity;therefore,the design and development of advanced electrocatalysts are crucial.A plethora of heterogeneous and homogeneous materials has been explored in the ECR.Among these materials,single-atom catalysts(SACs)have been the focus of most extensive research in the context of ECR.A SAC with isolated metal atoms dispersed on a supporting host exhibits a unique electronic structure,well-defined coordination environment,and an extremely high atom utilization maximum;thus,SACs have emerged as promising materials over the last two decades.Single-atom catalysis has covered the periodic table from d-block and ds-block metals to p-block metals.The types of support materials for SACs,ranging from metal oxides to tailored carbon materials,have also expanded.The adsorption strength and catalytic activity of SACs can be effectively tuned by modulating the central metal and local coordination structure of the SACs.In this article,we discuss the progress made to date in the field of single-atom catalysis for promoting ECR.We provide a comprehensive review of state-of-the-art SACs for the ECR in terms of product distribution,selectivity,partial current density,and performance stability.Special attention is paid to the modification of SACs to improve the ECR efficiency.This includes tailoring the coordination of the heteroatom,constructing bimetallic sites,engineering the morphologies and surface defects of supports,and regulating surface functional groups.The correlation of the coordination structure of SACs and metal-support interactions with ECR performance is analyzed.Finally,development opportunities and challenges for the application of SACs in the ECR,especially to form multi-carbon products,are presented.