Visible-light driven ZnIn2S4/TiO2-x heterostructure for boosting photocatalytic H2 evolution

Ti3+ doped titanium dioxide (TiO2-x) has attracted extensive attention owing to its potential application in visible-light driven photocatalysis. Herein, a visible-light responsive TiO2-x coupled with ZnIn2S4 was developed as a novel photocatalyst for hydrogen evolution reaction (HER). The energy band structures of TiO2-x and ZnIn2S4 obtained from the UV–vis DRS spectra and Mott-Schottky plots reveal a construction of type II heterojunction in ZnIn2S4/TiO2-x photocatalyst. This enhances the separation of photogenerated carriers and electron transfer (ET) rate, which are supported by the photoluminescence (PL) spectra and photocurrent response experiments. Therefore, under the optimal loading amount of ZnIn2S4 on TiO2-x (molar ratio of ZnIn2S4: TiO2-x = 0.5:1), this photocatalyst can derive a hydrogen evolution rate of 530 μmol g−1 h−1, much better than that of TiO2-x alone. In addition, non Ti3+ doped TiO2 loaded with equal amount of ZnIn2S4 was as a comparative sample and exhibited poorer photocatalytic activity than that of ZnIn2S4/TiO2-x, which further reflects superiority of Ti3+ doped TiO2-x.