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

[Display omitted] •Co9S8/CdIn2S4 ohmic junction with robust IEF was prepared.•Efficient H2 evolution and excellent stability were realized over 5% Co9S8/CdIn2S4.•Co9S8 nanotubes served as promising Co-based cocatalysts that can evidently enhance PHE activity.•The photocatalytic mechanism was proposed based on experimental results and DFT calculations. 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.