Photocatalytic Water Splitting Performance of p-n-Type NiWO4/ZnIn2S4 Heterojunctions

In this paper, p-n-type NiWO4(NWO)/ZnIn2S4(ZIS) heterojunctions were constructed by a two-step hydrothermal/water bath method. The influence of different loading amounts for NWO on the composition, morphology, band structure, light absorption and photocatalytic water splitting performance was investigated. The photocatalytic mechanism of NWO/ZIS system was also discussed by a series of advanced characterization tools. The results show that the composition and morphology of ZIS don't change significantly after loading NWO. Furthermore, the interface between the two materials contacts intimately and the two materials distribute uniformly. Consequently, the hydrogen evolution performance of NWO/ZIS has been markedly improved under the visible-light irradiation. Therein, the highest hydrogen production rate for NWO-35/ZIS samples is 5204.8 mu mol center dot g-1 center dot h-1, which is approximately 3.32 times higher than that of pure ZIS(1566.4 mu mol center dot g-1 center dot h-1). The cyclic experiment shows that NWO/ZIS system has excellent photostability. The band calculation and photoelectric dynamic results confirm the photogenerated charge transport mechanism driven by p-n-type internal electric field.