Synergistic Enhancement of Photocatalytic Hydrogen Evolution in ZnIn₂S₄/CuWO₄ via S-Scheme Heterojunction and Photothermal Effect

Abstract

The construction of integrated photothermal materials and photocatalysts has emerged as a promising approach to enhance photocatalytic hydrogen evolution reaction (HER) activity, yet the underlying synergistic mechanisms remain poorly understood. In this study, we successfully synthesized ZnIn2S4/CuWO4 (ZIS/CWO) S-scheme heterojunctions, combining photothermal and photocatalytic functionalities to improve HER efficiency. The CuWO4 component acted as a photothermal energy source, elevating the system’s temperature, enhancing charge transfer, and boosting the energy available for the photogenerated carriers in ZnIn2S4. Additionally, the S-scheme heterojunction effectively suppressed the recombination of photogenerated charge carriers, further improving the photocatalytic performance. Under visible light irradiation for 3 hours, the ZIS/CWO-3 heterojunction achieved a hydrogen evolution rate of 6.23 mmol g-1 h-1, which is 20.8 times higher than that of pure ZnIn2S4 (0.30 mmol g-1 h-1). This work presents a robust strategy for designing integrated photothermal-photocatalytic systems with significantly improved HER performance.