Zinc Vacancy‐Mediated S‐Scheme ZCS/ZnS‐Vzn Heterojunction for Efficient Photocatalytic Hydrogen Production

Photocatalytic H 2 generation via water splitting using sulfide semiconductors is hindered by narrow light absorption, rapid charge recombination, and photocorrosion. A core–shell ZCS/ZnS‐Vzn heterojunction was constructed with tunable zinc vacancies. These vacancies introduce a mid‐gap defect level for two‐step visible‐light absorption, form an ohmic‑like contact that directs S‐scheme charge transfer from ZnS‐Vzn to ZCS, and serve as hole traps (Vzn) to reduce the required sacrificial agent concentration from 20 to 10 vol%. The optimal composite achieves 2063.8 µmol h −1 g −1 H 2 evolution triggered by visible light, 25‐fold and 16‐fold higher than pristine ZnS‐Vzn and ZCS, respectively. The S‐scheme pathway also suppresses photocorrosion, ensuring excellent stability. This work demonstrates that vacancy‐mediated S‐scheme engineering offers a facile strategy for designing durable, high‐performance sulfide photocatalysts for solar fuel production.