Photoinduced Dynamic Electronic Asymmetry of Cu Dual‐Atom Sites Within Covalent Organic Frameworks Boosts Hydrogen Production

The development of efficient and cost-effective alternatives to noble metal cocatalysts for photocatalytic hydrogen evolution remains a significant challenge. Herein, we demonstrate a facile strategy for constructing atomically dispersed dual Cu sites within a covalent organic framework (COF), using molecular carboxylic acids as coordinating ligands. Through in situ spectroscopic characterization and theoretical calculations, we identified a light-induced dynamic electronic restructuring involving the reduction of one Cu(II) to Cu(I) within the dual-atom site, generating a mixed-valence state with asymmetric electronic configuration. This dynamic asymmetry facilitates electron transfer process and optimizes hydrogen intermediate adsorption. Enhanced H₂ generation is achieved, and the performance exceeds that of benchmark Pt cocatalyst. Furthermore, the molecular carboxylic acid-assisted strategy employed here is successfully extended to improve the H₂ evolution activity of Pt. This work offers an applicable method for constructing dual-atomic-site catalysts and provides insights into dynamic active sites in catalysis.