Organic-Inorganic Interfacial Charge-Directed Migration for Enhanced Photocatalytic Hydrogen Evolution Over...

Hydrogen-bonded organic frameworks (HOFs) have attracted increasing attention as promising photocatalysts owing to their well-defined crystalline structures and highly tunable architectures. However, their application in photocatalytic sacrificial hydrogen evolution remains constrained by inefficient separation of photogenerated charge carriers. Herein, we designed and synthesized a covalently bonded organic-inorganic type-II heterojunction composite comprising Cu_xO, HOFs, and persistent luminescence nanoparticles (PLNPs). The optimized Cu_xO/HOFs/PLNPs (3:1) sample delivered a high H₂ evolution rate of 70.62 mmol g^-1 h^-1 under visible-light irradiation (λ ≥ 420 nm) without any co-catalyst, which was 3.57-fold higher than that of the pristine HOFs. It also exhibited an apparent quantum efficiency of 3.09% and excellent long-term cycling stability. The enhanced photocatalytic activity is mainly attributed to the synergistic effect of efficient interfacial charge transfer and electron trapping. Specifically, the type-II band alignment drives the directional migration of photogenerated electrons, while the intrinsic electron-storage states of PLNPs effectively suppress charge recombination and facilitate charge transport. Meanwhile, variable-valence Cu_xO species provide abundant active sites for proton reduction. This work offers an effective interfacial engineering strategy for constructing efficient HOF-based photocatalysts.