Anionic Coordination‐Regulated Metal‐Organic Cages for Efficient CO 2 Photoreduction

Abstract Photocatalytic reduction of carbon dioxide (CO 2 ) provides a promising strategy for producing high‐value chemicals and fuels. However, developing high‐performance photocatalysts for CO 2 reduction remains a great challenge due to the poor stability of reaction intermediates. Herein, we present an anionic coordination strategy to facilitate the stabilization of intermediates by constructing halogen‐coordinated metal‐organic cages (MOCs) (Ni 8 L 12 X 4 , X = Cl, Br, I). Theoretical calculations show that the formation of *COOH intermediate is the rate‐limiting step and halogen coordination effectively regulates the energy barrier for this reaction. Notably, iodide anions significantly reduce the energy gap between the Ni d and iodide p orbitals, enhancing electron transfer from the Ni center to adsorbed CO 2 and promoting the production of *COOH. As a result, Ni 8 L 12 I 4 demonstrates superior performance with a CO production rate of 2680.23 µ mol g −1 h −1 and 95% selectivity, outperforming Cl‐ and Br‐coordinated Ni MOC by 200‐ and 5‐fold, respectively. This work opens a new coordination engineering strategy for fabricating efficient photocatalysts for CO 2 reduction.