Indium oxysulfide nanosheet photocatalyst for the hexavalent chromium detoxification and hydrogen evolution reaction

Indium oxysulfide nanosheet (In₂(O,S)₃ NS) had been successfully synthesized by a solution-based process at 90 °C. To further study some properties of photocatalyst, the 90 °C-prepared In₂(O,S)₃ NS was annealed at 350, 400, and 450 °C in air for 2 h. It was found that the nanosheet structure at 90 °C changed to nanoparticle at higher temperature. All the as-prepared and annealed photocatalysts were carefully characterized and examined toward photocatalytic hexavalent chromium (Cr(VI)) reduction. Among the photocatalysts, 90 °C-prepared In₂(O,S)₃ NS exhibited the greatest photocatalytic reduction of Cr(VI) without using any hole scavenger reagent under 150 W visible light illumination. After the Ag deposition on In₂(O,S)₃ NS, the photocatalyst could produce nearly 400 μmol/g hydrogen gas in ethanol solution under 150 W Xe-lamp irradiation for 5 h. The great performance of 90 °C-prepared In₂(O,S)₃ NS was due to the high surface area of nanosheet morphology and the formation of solid solution which significantly increased the visible light absorbance. The photocatalytic activities and their mechanisms of 90 °C-prepared In₂(O,S)₃ NS were evaluated and elaborated in this work.