Enhanced photocatalytic properties of ZnS/CdS/ZnCdS catalysts under visible light irradiation

The environmental damage caused by industrial waste is gaining attention. Although semiconductors are superior over photocatalysis and have a photo-corrosion issue, they are projected to have a long life. Herein, ZnS/CdS/ZnCdS catalysts were synthesised via a novel sol-gel method for improved dye degradation under visible-light irradiation. Several characterization techniques were used to investigate the phase structure, morphology, optical characteristics, surface area and chemical states, photocatalytic dye degradation of the prepared catalysts. The ZnCdS nanocatalyst exhibited superior catalytic efficiency than ZnS and CdS, and the highest dye degradation efficiency (99%) was recorded for MB and RhB after 150 and 180 min under visible light, respectively. This superior photocatalytic dye degradation performance was observed for ZnCdS nanocatalyst because of the improved crystalline structure (39 nm) with improved surface area (139 m2/g), tuneable band gap (2.49eV), effective electron-hole separation (Zn2+ and Cd2+) and high photo stability of ZnCdS. The effects of catalyst loading, reaction time, reusability, scavenger analysis and possible photocatalytic mechanisms were also investigated. This paper provides insight into the strategies for improving the dye degradation via composite catalyst synthesis.