Organic–Inorganic Interfacial Charge‐Directed Migration for Enhanced Photocatalytic Hydrogen Evolution Over Cu <i> _x </i> O/Hydrogen‐Bonded Organic Frameworks/Persistent Luminescence Nanoparticle Heterojunctions

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 x O, HOFs, and persistent luminescence nanoparticles (PLNPs). The optimized Cu x O/HOFs/PLNPs (3:1) sample delivered a high H 2 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 x O species provide abundant active sites for proton reduction. This work offers an effective interfacial engineering strategy for constructing efficient HOF‐based photocatalysts.