Efficient photocatalytic hydrogen production under visible light over a novel W-based ternary chalcogenide photocatalyst prepared by a hydrothermal process

Decahedral Cu₂WS₄ was synthesized by a facile hydrothermal method and employed as photocatalyst for photocatalytic hydrogen production for the first time. The hydrothermal method avoids the traditional use of H₂S for the preparation of such chalcogenide, which guarantees an environmental-friendly process. The properties of the Cu₂WS ₄ samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis reflectance spectra, etc. The results showed that the decahedral Cu₂WS₄ possessed a band gap of ca. 2.1ev. The photocatalyst was demonstrated to be very active under visible light for hydrogen production. Especially, Cu₂WS₄ synthesized at 200 °C for 72 h showed the highest activity with the apparent quantum yield of 11% at 425 nm. The correlation between the preparation parameters and the photocatalytic properties were investigated. It was expected this first report of W-based chalcogenide photocatalyst would add to the photocatalyst group and lead to the finding of new photocatalyst with much higher activity.