An Unlocked Two‐Dimensional Conductive Zn‐MOF on Polymeric Carbon Nitride for Photocatalytic H 2 O 2 Production

Abstract Developing highly efficient catalytic sites for O 2 reduction to H 2 O 2 , while ensuring the fast injection of energetic electrons into these sites, is crucial for artificial H 2 O 2 photosynthesis but remains challenging. Herein, we report a strongly coupled hybrid photocatalyst comprising polymeric carbon nitride (CN) and a two‐dimensional conductive Zn‐containing metal–organic framework (Zn‐MOF) (denoted as CN/Zn‐MOF(lc)/400; lc, low crystallinity; 400, annealing temperature in °C), in which the catalytic capability of Zn‐MOF(lc) for H 2 O 2 production is unlocked by the annealing‐induced effects. As revealed by experimental and theoretical calculation results, the Zn sites coordinated to four O (Zn‐O 4 ) in Zn‐MOF(lc) are thermally activated to a relatively electron‐rich state due to the annealing‐induced local structure shrinkage, which favors the formation of a key *OOH intermediate of 2e − O 2 reduction on these sites. Moreover, the annealing treatment facilitates the photoelectron migration from the CN photocatalyst to the Zn‐MOF(lc) catalytic unit. As a result, the optimized catalyst exhibits dramatically enhanced H 2 O 2 production activity and excellent stability under visible light irradiation.