Hydroxyl-mediated interfacial oxophilicity engineering for efficient CO2-to-C2+ oxygenates conversion at industrial current densities

Electrocatalytic CO 2 reduction (eCO 2 RR) to multi-carbon (C 2+ ) products is a promising pathway for renewable energy storage and carbon neutrality. However, selectively steering the reaction toward high-value C 2+ oxygenates, rather than ethylene, remains a major challenge due to the intertwined reaction pathways following the initial C–C coupling step. Herein, we propose a hydroxyl-mediated interfacial oxophilic engineering strategy to selectively stabilize oxygenated intermediates and promote their directional transformation into C 2+ oxygenates. In situ spectroscopic analyses and DFT calculations reveal that hydroxyl species preferentially anchor at low-coordinated Cu sites at the Cu/Cu 2 O interface, creating a locally oxophilic and chemically asymmetric microenvironment. This interfacial hydroxyl layer not only stabilizes Cu δ+ species under high current densities but also promotes the retention of *OCCHO and *CHO-like intermediates, while disfavoring their deoxygenation to ethylene. As a result, the catalyst achieves a C 2+ oxygenates Faradaic efficiency of 68% at an industrially relevant current density of 200 mA cm -2 in a 5 cm 2 membrane electrode assembly. This work highlights the critical role of interfacial oxophilicity in governing product selectivity and offers a generalizable design principle for constructing high-performance eCO 2 RR catalysts that break the traditional trade-off between C–C coupling efficiency and product selectivity. Hydroxyl-mediated Cu/Cu 2 O interfaces create a locally oxophilic, chemically asymmetric microenvironment, stabilizing Cu δ+ species and selectively retaining oxygenated intermediates (*OCCHO/*CHO), while suppressing ethylene formation. This enables highly selective C 2+ oxygenate production with 68% Faradaic efficiency at 200 mA cm -2 . This strategy highlights a generalizable design principle for engineering high-performance eCO 2 RR catalysts with enhanced C 2+ oxygenate selectivity. • Hydroxyl-mediated interface stabilizes Cu δ+ at high current densities. • Oxophilic, asymmetric microenvironment retains *OCCHO/*CHO intermediates. • Achieving 68% C 2+ oxygenate selectivity at 200 mA cm -2 in a 5cm 2 MEA.