Abstract
Electrochemical CO2 reduction simultaneously achieves conversion and storage of electrical energy as chemical energy through carbon recycling. Electrocatalysts with single-site and high efficiency for CO2 reduction have recently attracted much attention. In this review, the rational design strategies of single-site metal catalysts (SSMCs) for CO2 reduction are summarized. Particularly, we present the microenvironment engineering of SSMCs which entails atomic-scale design and nanoreactor construction. We further discuss the catalytic mechanisms, effects of the types, and coordination environments among metal species on tailoring catalytic activity and those nanoreactor features toward high-performance electrochemical CO2 reduction. Finally, we overview the current challenges and prospects of single-site metal catalysts for electrochemical CO2 reduction.