Chelated Linkage and Framework Isomerism Effect Toward Robust Zn‐Salen MCOFs for Dual‐Channel Overall H ₂ O ₂ Photosynthesis

Abstract 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 H ₂ O ₂ photosynthesis. Zn‐Salen‐MCOF with kgd‐v topology shows a higher H ₂ O ₂ photocatalytic production rate of 6617/3438 µmol gcat. ⁻¹ h ⁻¹ in pure water with/without additional O ₂ or air saturation, together with long‐time continuous H ₂ O ₂ photosynthesis performance (100 h). The framework isomerism effect and the chelated linkages contribute to the improved H ₂ O ₂ photosynthesis efficiency and stability of it. A three‐step 2e⁻ WOR with the initial H ₂ O adsorption over the ZnO ₂ N ₂ unit and a four‐step 2e⁻ ORR reaction mechanism with the key H _ad adsorption at the pyrazinic N site are proposed. This study paves the way for developing robust MCOF‐based photocatalysts for dual‐channel H ₂ O ₂ production based on chelated linkage and framework isomerism effect.