Design Strategies of Cu-Based Tandem Catalysts for Efficient Electrochemical CO2 Reduction to C2+ Products

Abstract Electrochemical CO2 reduction reaction (CO2RR) offers a promising route to convert CO2 into value-added fuels and chemicals using renewable electricity. Cu-based catalysts are uniquely capable of producing C2+ hydrocarbons and oxygenates through C–C coupling, but their performance is limited by insufficient *CO coverage, broad product distributions, competing hydrogen evolution, and stability issues at high current densities. Tandem catalysis addresses these challenges by integrating CO-generating components with Cu-based C–C coupling sites. This review summarizes recent advances in Cu-based tandem catalysts under flow-cell and industrially relevant conditions, focusing on spatially separated systems, Ag–Cu bimetallic interfaces, single-atom alloys, and SAC–Cu tandem architectures. Key design principles include regulating CO generation, transport, interfacial structure, and coupling pathways.