Selective Formation of Multi-Carbon Products via Interface-Driven Electrochemical CO Reduction on Cu–Ag Catalysts

Electrochemical CO reduction to multi-carbon (C₂₊) products present a promising strategy to address global warming and energy shortages. However, this reaction is often hindered by inefficient C─C coupling and the instability of key intermediates on catalysts. Here, a Cu─Ag bimetallic catalyst (CuAg-PMB) with abundant interfacial sites is prepared using a novel differential-precipitation microzone-barrier reduction method. Owing to its high interface density, the CuAg-PMB catalyst achieves a record Faradaic efficiency of 93.2% for C₂₊ products at a current density of −200 mA cm⁻². In situ electrochemical spectroscopy and DFT calculations reveal that the enriched Cu─Ag interfaces enhance ^*CO adsorption, facilitate water dissociation, and promote the hydrogenation of ^*CO to ^*COH, thereby boosting C─C coupling efficiency. These results underscore the critical role of interfacial engineering in enabling selective C₂₊ formation and offer a compelling design strategy for next generation electrocatalysts.