Liquid‐Liquid Interface ‐Driven Reconstruction of CuAg Nanocomposites for Selective CO ₂ to C ₂ H ₄ Electroreduction

The electrochemical CO₂ reduction reaction (CO₂RR) to multicarbon products such as C₂H₄ is critical for sustainable energy conversion but remains a significant challenge. Cu-based nanocatalysts can facilitate C─C coupling for C₂₊ product generation, yet their catalytic efficiency and selectivity require further improvement. In this study, a liquid-liquid interface etching strategy is employed, using Cu nanocubes as templates and aqueous AgNO₃ as the etchant to synthesize well-defined CuAg nanocomposites. Among these, the optimized Cu₆₇Ag₃₃ composite nanocubes achieved a ethylene (C₂H₄) Faraday efficiency (FE) of 43.90% and a partial current density of 21.50 mA cm^-2at -1.50 V_RHE. This work demonstrates a versatile approach to integrate secondary metal active sites via directional confined etching, while reconstructing catalytic interfaces to enhance C─C coupling and C₂H₄ selectivity. These findings provide a strategic framework for the rational design of efficient CO₂RR catalysts, advancing the development of sustainable carbon conversion technologies.