Synthesis of ZnO-ZnS Nanocomposite and its Application in Photocatalytic Degradation of Direct Red 80 Dye

ZnO-ZnS nanocomposite was synthesized by sol-gel method with thiourea precursor. Nanocomposite properties were evaluated by XRD, SEM, FTIR and UV-vis DRS. XRD and FTIR results confirmed the presence of the crystalline structure of ZnO and ZnS in the nanocomposite. SEM analysis confirmed the synthesis of photocatalyst in nanometer dimensions. The fabrication of nanocomposite increased the light absorption efficiency compared to pure ZnO and the band gap ofZnO-ZnS photocatalyst decreased to 3 eV. ZnO-ZnS nanocomposite was investigated for the photocatalytic degradation of direct red 80 (DR80) under ultraviolet light irradiation. The DR80 degradation reached 98.76% after 60 minutes irradiation, which is 40% higher than that of ZnO nanoparticles. Reducing the band gap of nanocomposite and proper charge transfer in the created heterojunction caused a significant increase in the photocatalytic activity. A mechanism for the ZnO-ZnS nanocomposite performance was presented. Stability of nanocomposite was evaluated after 4 times of recycling.