Interfacial Charge Transfer Enhanced Photocatalytic H2 Evolution Over CdZnS@ZnO Heterostructures

Metal sulfides are promising photocatalysts for solar‐driven hydrogen evolution. However, their practical efficiency is severely limited by the rapid recombination of photogenerated charge carriers. Herein, a core–shell CdZnS@ZnO heterojunction photocatalyst is rationally constructed by coating CdZnS nanoparticles onto hexagonal ZnO nanobricks to regulate interfacial charge‐transfer. The formation of a built‐in electric field at the CdZnS/ZnO interface induces directional migration of photogenerated electrons from the conduction band of ZnO to that of CdZnS, accompanied by hole transfer from CdZnS to ZnO. This spatial separation of charge carriers effectively suppresses electron–hole recombination and promotes electron accumulation in CdZnS for hydrogen evolution reactions. As a result, the optimized CdZnS(9.9%)/ZnO photocatalyst delivers a hydrogen evolution rate of 1.39 mmol·g−1·h−1, which is 2.2‐fold and 3.2‐fold higher than those of pristine CdZnS and ZnO, respectively. Combined experimental investigations and theoretical calculations elucidate the interfacial charge‐transfer mechanism responsible for the enhanced photocatalytic performance.