Covalent Organic Framework Encapsulating Layered Oxide Perovskite for Efficient Photosynthesis of H₂O₂

Abstract Driving efficient artificial photosynthesis of H 2 O 2 is highly desirable in both academic and industrial fields. Here, a new core–shell Bi 3 TiNbO 9 @C 4 N heterojunction is constructed for efficient photocatalytic H 2 O 2 production by in situ encapsulating an ultrathin layer of covalent organic framework material (C 4 N) on Aurivillius‐type Bi 3 TiNbO 9 microsheets. The porous C 4 N layer is found to enhance visible‐light absorption ability and facilitate the adsorption and activation of the reactants and intermediates. The hybrid heterojunction follows an S‐scheme charge transfer with the assistance of a strong internal electric field (IEF), which promotes the spatial separation of photogenerated carriers effectively and maintains their strong redox abilities. As a result, the optimized Bi 3 TiNbO 9 @C 4 N unveils a high H 2 O 2 yield rate of 1.25(2) mmol g −1 h −1 in the absence of sacrificial agents and cocatalyst, 10.9 and 3.5 folds higher than those of pristine Bi 3 TiNbO 9 and C 4 N catalysts, respectively. This work provides an in situ encapsulating strategy to decorate covalent organic frameworks (COFs) on oxide perovskites for artificial photosynthesis of H 2 O 2 , which may stimulate the intensive investigation interests of functional materials/COFs heterojunction materials for various photocatalysis applications.