Ultrathin 2D/2D ZnIn2S4/La2Ti2O7 nanosheets with Z-scheme heterojunction for enhanced photocatalytic hydrogen evolution

The layered perovskite lanthanum titanate (La2Ti2O7) is a good photocatalytic material owing to its high stability, strong redox ability, and non-toxicity. However, its inherent wide bandgap limits its application in photocatalytic hydrogen evolution. Therefore, combining La2Ti2O7 with two-dimensional (2D) narrow-bandgap semiconductors to form a 2D/2D layered structures is the preferred strategy to improve its photocatalytic performance. In this study, a novel 2D/2D ZnIn2S4/La2Ti2O7 Z-scheme heterojunction was prepared through the solvothermal method. The experimental results show that when the molar ratio of La2Ti2O7 to ZnIn2S4 is 1:4, the hydrogen evolution rate of the composite under ultraviolet-visible light reaches 6.97 mmol·g1·h1, which is 3.5 times higher than that of the pure ZnIn2S4. The results of the morphological characterization of the samples and the photoelectrochemical measurements show that channels for the rapid transfer of carriers are generated by the unique 2D/2D structure of these samples, and the separation and migration efficiency of the photogenerated carriers gets significantly improved due to the formation of the Z-scheme heterojunction. This study provides useful insight into the modulation of wide-bandgap semiconductors and the research on solar energy conversion.