Construction of urchin-like ZnIn2S4-Au-TiO2 heterostructure with enhanced activity for photocatalytic hydrogen evolution

Abstract

The ternary ZnIn2S4-Au-TiO2 Z-scheme heterostructure photocatalysts has been fabricated by selecting effectiveness Au NPs as a solid electron mediator, via a chemical-deposition process for water splitting under simulated solar light irradiation. The designed photocatalysts exhibit high surface area and wide light absorption range, which significantly enhance photocatalytic efficiency. At an optimal ratio of 24 wt% Au NPs and 60 wt% ZnIn2S4, the obtained ZnIn2S4-Au-TiO2 photocatalysts achieve the highest H2 production with the rate of 186.3 μmol g−1 h−1, and the O2 production rate is reached to 66.3 μmol g−1 h−1. It showed that the ZnIn2S4-Au-TiO2 composite structures exhibit significantly better photocatalytic activity than ZnIn2S4-TiO2 and Au-ZnIn2S4-TiO2 structure. Such an excellent performance should be attributed to the Au NPs in the Z-scheme system structure which favor to enhance the transfer rate of the photogenerated electrons and holes and remain strong redox ability of the photocatalysts. It is worth pointing out that the unique Z-scheme ZnIn2S4-Au-TiO2 heterostructure shows great solar activity toward water splitting into renewable hydrocarbon fuel.