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

Abstract The production of multi‐carbon compounds through CO₂ photoreduction (CO₂PR) 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 (Mo₇O₂₄⁶⁻) and hydroxyl vacancy (V_OH). In contrast to the Ni sites unmodified with Mo₇O₂₄⁶⁻ 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 C₂H₆, which represent one of the best results for CO₂PR to C₂H₆. 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 Mo₇O₂₄⁶⁻ synergistically constructed electron‐rich Ni sites. Such Ni sites efficiently catalyze CO₂ conversion to C₂H₆ by enhancing the adsorption of ^*CO, promoting subsequent hydrogenation, and enabling low energy barriers for CO₂ hydrogenation to ^*OCOH and the coupling of ^*CH₃ intermediates. This study provides deeper insights into the photocatalytic process, highlighting the significance of tailored active sites for efficient CO₂ conversion.