Building a Confluence Charge Transfer Pathway in COFs for Highly Efficient Photosynthesis of Hydrogen Peroxide from Water and Air

Abstract Sunlight‐driven photosynthesis by covalent organic frameworks (COFs) from water and air without using sacrificial reagents is a promising H 2 O 2 fabrication approach but is still restricted by the insufficient charge separation and sluggish 2 e − water oxidation process. Herein, we provide a facile strategy to simultaneously improve charge separation and water oxidation in COFs via confining the charge transfer pathways from two diversion ones to a confluence one through regulating the site of nitrogen in bipyridine. Combining in‐situ characterization with computational calculations, we reveal that compared to COF‐BD1 containing two diversion charge transfer pathways, the charge transfer pathway in COF‐BD2 is confined to a confluence due to the electron‐deficiency effect of nitrogen, which greatly accelerates the intermolecular and out‐of‐plane charge transfer. Via effectively reducing the energy barrier of rate‐determining water oxidation reaction (WOR), the subsequent water oxidation process to produce the key *OH intermediate in COF‐BD2 is also greatly facilitated, boosting the yield of H 2 O 2 (5211 µmol g −1 h −1 ) from water, oxygen, and light without sacrificial agents or additional energy consumption. We further demonstrate that H 2 O 2 can be efficiently produced by COF‐BD2 in a broad pH range, in real water, and in an enlarged reactor using natural sunlight for water decontamination.