Recent advances in the rational design of single-atom catalysts for electrochemical CO_(2) reduction

Electrochemical CO_(2) reduction(CO_(2)R)represents a sustainable way to store intermittent renewable energies and produce carbon-neutral fuels,yet the energy efficiency remains a huge bottleneck owning to its sluggish kinetics and complex reaction pathways.Highly active,selective,and robust electrocatalysts are strongly demanded to accelerate CO_(2) conversion and deploy this technology to practical applications.In this review,we focus on single-atom catalysts(SACs),a unique category of electrocatalysts with atomically dispersed metal active sites,which have shown distinctive performances in CO_(2)R and offer an ideal platform for in-depth mechanistic studies at the atomic level.Despite various SACs with attractive CO_(2)R performances have been reported,the relationship between electronic/geometric structure of SACs and the corresponding electrocatalytic performance still needs to be discussed with caution.Here we take a broad overview on the recent progress in understanding the structure–function correlation of SACs in CO_(2)R,with the purpose of providing deep insights and guiding the future rational design of SACs.First,we provide the fundamental understandings of CO_(2)R on SACs,following different reaction pathways.Then,we describe the progresses in the development of well-defined SACs and the mechanistic studies on the influences from particular structural parameters,such as first-shell and second-sphere coordination,conductive supports and interface with a secondary catalyst.Finally,some perspectives are highlighted on the path towards efficient CO_(2)R on SACs.