Synergistic Engineering of Electron‐Enriched Nickel Sites for Highly Efficient Photocatalytic CO₂ Reduction to C₂H₆

Abstract The production of multi‐carbon compounds through CO 2 photoreduction (CO 2 PR) holds great promise but faces challenges due to high kinetic barriers and the sluggish process of C‐C coupling. Overcoming these obstacles requires fine engineering of active sites. In this study, Ni active sites are engineered through the synergistic effect of metal‐oxo cluster (Mo 7 O 24 6− ) and hydroxyl vacancy (V OH ). In contrast to the Ni sites unmodified with Mo 7 O 24 6− and V OH , which are unable to produce multi‐carbon products, the constructed electron‐enriched Ni active sites exhibit an impressive selectivity of up to 43.02% and a high yield rate of 246.70 µmol g −1 h −1 for C 2 H 6 , which represent one of the best results for CO 2 PR to C 2 H 6 . Through a comprehensive investigation involving operando experiments and theoretical simulations, hydroxyl vacancy and the formed Mo─O─Ni bonds is demonstrated due to the filling of hydroxyl vacancies with oxygen atoms from Mo 7 O 24 6− synergistically constructed electron‐rich Ni sites. Such Ni sites efficiently catalyze CO 2 conversion to C 2 H 6 by enhancing the adsorption of * CO, promoting subsequent hydrogenation, and enabling low energy barriers for CO 2 hydrogenation to * OCOH and the coupling of * CH 3 intermediates. This study provides deeper insights into the photocatalytic process, highlighting the significance of tailored active sites for efficient CO 2 conversion.