CuGa Alloy Catalysts Enable C–C Coupling for Electrocatalytic CO ₂ Reduction into C ₂₊ Products

Electrocatalytic CO2 reduction reaction (eCO2RR) offers a sustainable route for converting CO2 into value-added chemicals, contributing to carbon neutrality. While high selectivity toward C1 products has been achieved, the efficient production of multicarbon (C2+) compounds remains challenging due to the high energy barriers of C–C coupling. Copper-based catalysts are promising for C2+ generation owing to their unique *CO binding energy, yet they suffer from low selectivity and stability. Alloying copper (Cu) with other metals is an effective strategy for regulating intermediate adsorption and facilitating C–C coupling. In this study, an efficient CuGa solid solution alloy electrocatalyst for the eCO2RR was synthesized, employing only straightforward immersion drying and subsequent reduction annealing processes. At an applied potential of −1.19 V vs RHE, this catalyst exhibited a high Faradaic efficiency of 66.27% for C2+ products, significantly suppressing C1 pathways. It also demonstrated remarkable stability, maintaining structural and morphological integrity even after 12 h of electrolysis at a current density of 300 mA/cm2. Density functional theory calculation integrated with in situ characterization revealed that synergistic interaction between Cu and Ga enhances the adsorption of key intermediates (*COOH and *CO) and reduces the energy barrier of *CO dimerization. This work provides insights into the design of efficient and stable Cu-based electrocatalysts for C2+ production via an electrochemical method.