Novel Zn0.8Cd0.2S/g-C3N4 heterojunctions with superior visible-light photocatalytic activity: Hydrothermal synthesis and mechanism study

A simple hydrothermal method was used to fabricate a novel series of heterostructured Zn0.8Cd0.2S/g-C3N4 photocatalysts. The photocatalytic activity of the Zn0.8Cd0.2S/g-C3N4 was evaluated by the degradation of methylene blue (MB) under visible light irradiation. The as-prepared heterostructured Zn0.8Cd0.2S/g-C3N4 heterostructures showed enhanced photocatalytic activity for the degradation of MB, with compared to the pure Zn0.8Cd0.2S and g-C3N4. An optimum photocatalytic activity was observed over 50 wt% Zn0.8Cd0.2S incorporated g-C3N4 nanocomposite. The superior photocatalytic performance of Zn0.8Cd0.2S/g-C3N4 could be ascribed to its strong absorption in the visible region and low recombination rates of photoinduced electron-hole pairs because of the heterojunction formed between Zn0.8Cd0.2S and g-C3N4. We proposed the scheme for electron-hole separation and transport for the visible-light-driven Zn0.8Cd0.2S/g-C3N4 hybrid photocatalyst. It was found that the photodegradation of MB molecules is mainly attributed to the oxidation action of the generated O-2(center dot-) radicals and partly to the action of h(vb)(+) via direct hole oxidation process. (C) 2014 Elsevier B.V. All rights reserved.