Atomic regulation of metal-organic framework derived carbon-based single-atom catalysts for the electrochemical CO₂reduction reaction

Metal-organic framework (MOF) derived single-atom catalysts (SACs) feature unique active sites and adjustable topological structures, exhibiting high electrocatalytic performance in carbon dioxide reduction reactions (CO2RR). By modulating elements and atomic structures of MOF-derived SACs, the reaction pathway of CO2RR can be precisely regulated with designed conversion on CO, formate, methanol, methane, ethanol, acetone and other substances. In this review, the latest advances in MOF-derived SACs for CO2RR are comprehensively discussed. Main fabrication strategies of MOF-derived SACs, especially metal node strategy, coordination capture strategy and space restriction strategy, are introduced. Further regulations of the coordination environment of central atoms, including symmetrical M-N4 atomic interfaces, asymmetrical M-Nx atomic interfaces and hetero-atom doped atomic interfaces as well as the influence on catalytic performances are systematically discussed. For deep exploration of the mechanism of catalytic activity, new characterization techniques on SACs are illustrated, with emphasis on identifying the catalytic sites, geometrical structures and their dynamic behavior. Based on this, we finally present recent convincing studies of MOF-derived SACs on CO2RR categorized by the catalyzed products (C1 species and C2+ species). We hope this review will provide new insights on future research of SACs and CO2RR.