Pyrrolidone‐Bridged Ag–Cu 2 O Heterointerfaces Enable Selective C–C Coupling for Efficient Electrochemical CO 2 Reduction

Cu 2 O‐derived catalysts are promising for electrochemical CO 2 reduction (CO 2 RR) because Cu + sites and dynamically reconstructed Cu + /Cu 0 interfaces can stabilize CO‐derived intermediates and facilitate C–C coupling toward C 2+ products. However, their C 2+ selectivity remains limited despite advances in morphology and surface engineering. Here, we propose a dual‐modification strategy by co‐engineering Cu 2 O with Ag and polyvinylpyrrolidone (PVP). Ag increases local CO coverage, while PVP modulates the electronic structure of Cu/Ag sites, jointly promoting C–C coupling. This synergistic interface establishes a locally alkaline, carbonate‐rich microenvironment that facilitates dual hydrogen‐source utilization and enhances ethanol production. The catalyst achieves Faradaic efficiencies of 52.2% for ethanol and 72.2% for total C 2 products, with stable operation over 12 h. In situ X‐ray absorption spectroscopy reveals partial recovery of Cu + via Ag–PVP coupling during electrolysis, while in situ Raman spectroscopy confirms a shift from bicarbonate to carbonate‐dominated interfacial chemistry. These results demonstrate that coordinated electronic and microenvironmental regulation effectively overcomes key limitations in Cu 2 O‐based CO 2 RR, providing a rational design strategy for high‐performance C 2+ ‐selective electrocatalysts.