Chelated Linkage and Framework Isomerism Effect Toward Robust Zn‐Salen MCOFs for Dual‐Channel Overall H2O2 Photosynthesis

It remains challenging to synthesize effective and photocorrosion‐tolerated organic photocatalysts for two‐electron oxygen reduction reaction (2e⁻ ORR) and water oxidation reaction (2e⁻ WOR). Herein, two isomeric Zn‐Salen metal covalent organic frameworks (Zn‐Salen‐MCOFs) with kgd‐v or hcb topology are designed as robust and efficient photocatalysts for dual‐channel H2O2 photosynthesis. Zn‐Salen‐MCOF with kgd‐v topology shows a higher H2O2 photocatalytic production rate of 6617/3438 µmol gcat.−1 h−1 in pure water with/without additional O2 or air saturation, together with long‐time continuous H2O2 photosynthesis performance (100 h). The framework isomerism effect and the chelated linkages contribute to the improved H2O2 photosynthesis efficiency and stability of it. A three‐step 2e⁻ WOR with the initial H2O adsorption over the ZnO2N2 unit and a four‐step 2e⁻ ORR reaction mechanism with the key Had adsorption at the pyrazinic N site are proposed. This study paves the way for developing robust MCOF‐based photocatalysts for dual‐channel H2O2 production based on chelated linkage and framework isomerism effect.