Synergistic enhancement of photocatalytic hydrogen evolution in ZnIn2S4/CuWO4via an S-scheme heterojunction and the 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 h, the ZIS/CWO-3 heterojunction achieved a hydrogen evolution rate of 6.27 ± 0.04 mmol g⁻¹ h⁻¹, which is 21.7 ± 0.9 times higher than that of pure ZnIn₂S₄ (0.29 ± 0.01 mmol g⁻¹ h⁻¹). This work presents a robust strategy for designing integrated photothermal–photocatalytic systems with significantly improved HER performance.