From Precatalysts to Real Active Phases: Dynamic Reconstruction of CO2 Reduction Electrocatalysts

Abstract Electrochemical CO2 reduction reaction (CO2RR) provides a promising way to convert CO2 into fuels and value-added chemicals using renewable electricity. However, many CO2RR catalysts do not keep their original structures under reaction conditions. They often undergo dynamic reconstruction, including changes in the oxidation state, coordination environment, phase composition, morphology, defect density, and interfacial structure. These reconstructed states usually serve as the real active phases and strongly affect activity, selectivity, and stability. This review summarizes recent progress in understanding catalyst reconstruction during CO2RR. We first clarify the concept of precatalyst reconstruction and distinguish initial structures from real active phases. We then discuss the intrinsic and external factors that drive reconstruction. We further examine representative reconstructed catalysts, including Cu-based, non-Cu metal, and MOF- or coordination-compound-derived systems. We also highlight in situ characterization and simulation methods. Finally, we discuss key challenges and future opportunities for catalyst reconstruction.