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

Abstract

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.