Interface engineering of Co₉S₈/CdIn₂S₄ ohmic junction for efficient photocatalytic H₂ evolution under visible light

The design and development of high-performance photocatalysts from three aspects of simultaneous enhancement of light harvest, carrier migration rate, and redox reaction rate is still a great challenge. Herein, a novel Co₉S₈/CdIn₂S₄ ohmic junction with a robust internal electric field (IEF) is successfully prepared via hydrothermal and in situ synthesis methods and is used for effective photocatalytic H₂ evolution (PHE). Under simulated visible light irradiation, the PHE rate of 5% Co₉S₈/CdIn₂S₄ can reach 1083.6 μmol h^-1 g^-1, which is 6.4 times higher than that of CdIn₂S₄ (170.5 μmol h^-1 g^-1). The enhanced PHE performance is mainly ascribed to the improved light harvest and carrier separation efficiency and fast surface H₂ evolution kinetics. Moreover, Co₉S₈ nanotubes serve as promising Co-based cocatalysts that can evidently enhance PHE activity. Additionally, Co₉S₈/CdIn₂S₄ shows superior stability because the photogenerated carrier transfer path restrains the photocorrosion behavior. The photocatalytic mechanism is proposed based on experimental results and DFT calculations. This work offers new insights for the design and development of highly active photocatalysts from interface engineering.