Structure Sensitivity in Single-Atom Catalysis toward CO₂ Electroreduction

Owing to unique electronic structure and high atom utilization, single-atom catalysts (SACs) have displayed unprecedented activity and selectivity toward a wide range of catalytic reactions, including electrocatalytic CO2 reduction reaction (CO2RR), which holds great promise in reducing carbon emission and storing renewable energy. The activity and selectivity of CO2RR is closely related to structural characteristics of specific SACs. Here we discuss the fundamental understanding of the structure sensitivity in single-atom catalysis toward CO2RR using selected examples. The influences of the speciation of metal centers and coordination environments on catalytic performances are summarized. The importance of using in situ and operando characterizations to reveal dynamic structural evolution under reaction conditions and to identify active sites of SACs is highlighted. The mechanistic understanding of the unique role of SACs in tandem CO2RR catalysis is also discussed. We also illustrate existing challenges and research opportunities in investigating the structure–performance correlations of SACs for CO2RR.