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

Copper (Cu) has been widely recognized as a promising catalyst for electrocatalytic CO₂ reduction (CO₂R) into value-added multi-carbon (C₂₊) chemicals. However, the limited selectivity of C₂₊ 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 CO₂R performance, delivering a Faradaic efficiency (FE) for C₂₊ products of 73.6% (ethylene 54.16% and ethanol 19.44%), at a current density of − 221.7 mA/cm². 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 CO₂ electroreduction pathway toward C₂₊ products. This work provides new insights into constructing reconstruction-resistant Cu-based catalysts that enable efficient and stable CO₂-to-C₂₊ conversion.