A NiS co-catalyst decorated Zn3In2S6/g-C3N4 type-II ball-flower-like nanosphere heterojunction for efficient photocatalytic hydrogen production

Abstract

Promoting the separation of photogenerated electron–hole pairs and enhancing the charge carrier transfer are critical in photocatalysis. In our work, a ball-flower-like NiS/Zn₃In₂S₆/g-C₃N₄ photocatalyst fabricated by a hydrothermal method exhibited superior performance for photocatalytic water splitting. The optimized 2.0% NiS/Zn₃In₂S₆/g-C₃N₄ rivaled noble metal based Pt/g-C₃N₄ and showed an apparent quantum efficiency (AQE) of 24.3% at 420 nm, with a H₂ yield of 4.135 mmol g⁻¹ h⁻¹, which was 30.4 and 9.51 times that of pure g-C₃N₄ and binary Zn₃In₂S₆/g-C₃N₄ composites, respectively. The experimental and characterization results suggested that the heterojunction formed between Zn₃In₂S₆/g-C₃N₄ and the decorating NiS co-catalyst cooperatively suppressed the electron–hole recombination and facilitated the charge carrier transfer, thus resulting in significant improvement of the H₂ evolution performance. Moreover, the increased specific surface area and the enhanced visible-light absorption also contributed to superior water splitting performance. The prepared ternary catalytic system with the heterojunction and non-noble metal co-catalyst has great potential as an alternative to noble metals for achieving cost-efficient water splitting systems.