Photodecomposition of H2S to H2 over CdxZn1−xS composite photocatalysts

A series of CdxZn1−xS (x = 0.1–0.9) photocatalysts were prepared by coprecipitation. They could form solid solution semiconductors with hexagonal phase in agreement with pure CdS by characterization of XRD. The photophysical properties of CdxZn1−xS photocatalysts were measured by UV-Vis diffuse reflectance spectrum and surface photovoltage spectroscopy (SPS). The band gap energy gradually reduced with the increasing of x value in CdxZn1−xS, and when x = 0.7, the Cd0.7Zn0.3S photocatalyst had the strongest surface photovoltage. CdxZn1−xS photocatalysts were used in the photodecomposition of H2S to H2. The evolution rate of H2 over the Cd0.7Zn0.3S photocatalyst was also the highest among CdxZn1−xS photocatalysts. And the effect of calcination temperature on the evolution rate of H2 was investigated and the optimum temperature was 650°C.