Highly Stable Cuδ+ Sites at Reconstruction-Resistant Al‒O‒Cu Bridge Bond for Boosting CO2 Electroreduction into Multi-Carbon Products

Abstract Copper (Cu) has been widely recognized as a promising catalyst for electrocatalytic CO 2 reduction (CO 2 R) into value-added multi-carbon (C 2+ ) chemicals. However, the limited selectivity of C 2+ products persists due to the inactivation of precisely designed active sites triggered by uncontrollable reconstruction. Herein, we report the successful synthesis of the electrocatalysts of Lewis-acidic aluminum (Al)-doped copper oxides (AlCuO x ) with exposed abundant atomic-scale Al − O − Cu sites. The strong Al − O − Cu bridge bonds effectively suppress surface electrochemical reconstruction, and highly stable Cu δ + species are obtained. The AlCuO x catalyst exhibits an excellent electrocatalytic CO 2 R performance, delivering a Faradaic efficiency (FE) for C 2+ products of 73.6% (ethylene 54.16% and ethanol 19.44%), at a current density of − 221.7 mA/cm 2 . The analyses of in situ spectroscopy and theoretical calculations confirm that the high electron localization of Cu active sites in AlCuO x strengthens the interactions between Cu and linearly bonded *CO (*CO L ) through p − d orbital hybridization, thus facilitating C − C coupling and steering the CO 2 electroreduction pathway toward C 2+ products. This work provides new insights into constructing reconstruction-resistant Cu-based catalysts that enable efficient and stable CO 2 -to-C 2+ conversion.