Controlled Sulfidation‐Induced ZnO/ZnS S‐Scheme Heterojunctions for Efficient Photocatalytic Hydrogen Evolution

ABSTRACT Developing efficient and durable photocatalysts for solar‐driven hydrogen production remains a critical challenge for sustainable energy technologies. Herein, we report a robust ZnO/ZnS heterojunction nanocomposite prepared via a facile hydrothermal sulfidation strategy, in which the surface transformation of flower‐like ZnO into ZnS can be precisely regulated by adjusting the sulfidation time. Among the obtained samples, the optimized ZnO/S‐24 delivers an outstanding hydrogen evolution rate of 21.08 mmol·g −1 ·h −1 under visible light irradiation, approximately 22 times higher than that of pristine ZnO, and shows excellent cycling stability. Comprehensive structural and physicochemical characterizations reveal that the superior performance arises from the synergistic integration of three key factors: a well‐constructed interfacial S‐scheme heterojunction, which promotes directional charge separation while preserving strong redox potentials; an almost twofold increase in specific surface area, which provides abundant accessible active sites; and reduced interfacial charge‐transfer resistance, as confirmed by photoelectrochemical measurements. XPS, UPS, EPR, and Mott‐Schottky analyses collectively verify the formation of an internal electric field and the S‐scheme charge transfer pathway across the ZnO/ZnS interface. This work not only demonstrates an effective route to engineer high‐performance ZnO‐based heterostructures, but also offers valuable insight into the rational design of sulfide‐modified oxide photocatalysts for efficient solar‐to‐hydrogen conversion.