Abstract: Cooperative coupling of photocatalytic hydrogen peroxide production with organic pollutants degradation has an expansive perspective in energy storage and environmental conservation. Herein, an S-scheme het-erojunction is constructed by hybridizing a 3D flower like Schiff-based covalent organic framework (COF) with a porous structure g-C₃ N₄, and a comprehensive strategy is proposed to achieve efficient H₂ O₂ pro-duction yield coupling highly Rhodamine B (RhB) degradation rate. The charge carrier transfer mechanism is validated by an in-situ X-ray photoelectron spectroscopy, the density functional theory calculation, and a femtosecond transient absorption spectroscopy. Interestingly, the COF/g-C₃ N₄ S-scheme heterojunction exhibits better charge separation efficiency compared to bare COF and pure g-C₃ N₄, resulting in ameliora-tive photocatalytic activity. In addition, RhB is employed to consume photogenerated holes. Remarkably, 2307 μmol g^-1 h^-1 H₂ O₂ achieved over 10 %-COF/g-C₃ N₄ composite in RhB solution and O₂ atmosphere, and 100 %-RhB degradation rate obtained at 45 min. This work improves a facile strategy to ameliorate Schiff COF-based S-scheme heterojunction for efficient H₂ O₂ production with full hole-electron utilization ability.

Key words: Covalent organic framework, S-scheme heterojunction, Rhodamine B degradation, H₂ O₂ production, Carrier migration and separation