High visible light responsive ZnIn2S4/TiO2-x induced by oxygen defects to boost photocatalytic hydrogen evolution

Photocatalytic H2 evolution provides an upcoming route for the production of clean fuel via the conversion of solar energy. TiO2, as a potential semiconductor material, is restricted by its faint absorption of visible light, thus limiting its application in water splitting. Herein, high visible light responsive ZnIn2S4/TiO2-x nanotube arrays for photocatalytic hydrogen evolution were fabricated by two-step reaction. ZnIn2S4/TiO2-x nanotube arrays exhibited the photo response from UV to visible-light region due to the introduction of oxygen vacancies and visible-light driven ZnIn2S4. Moreover, the heterojunction improved the separation of photogenerated carriers and boosted the electron transfer from ZnIn2S4 to TiO2-x, thereby increasing the longevity of active electrons, which enhanced the photocatalytic activity for hydrogen evolution. An outstanding H2 production rate of 581.1 μmol h−1 g−1 was obtained and an apparent quantum yield (AQY) up to ∼ 1.42% was achieved. This work demonstrates that the defect-induced bandgap engineering of semiconductor photocatalysts is a potential way to extend the optical absorption property of TiO2 to visible light even or NIR and enhance the photocatalytic activity.