Development of tungsten disulfide ZnO nanohybrid photocatalyst for organic pollutants removal

In this study, ZnO and ZnO/WS2 nanohybrid were synthesized by a facile microwave approach. Nanohybrid phase purity and structural features were examined through XRD, SEM-EDS, and EDS color mapping techniques. The optical absorbance and band gap energy of the ZnO/WS2 nanohybrid was measured by the UV-DRS. Functional group features on the ZnO/WS2 nanohybrid was investigated by the FT-IR spectroscopy. Further, the position of the conduction band and conductivity of the prepared ZnO/WS2 nanohybrid was studied by the Mott-Schottky and Nyquist plot techniques. The photocatalytic properties of the ZnO/WS2 nanohybrid were evaluated through the degradation of anionic and cationic organic pollutants such as methylene blue, bromophenol-B and 4-nitrophenol respectively. The organic pollutants degradation efficiency was determined by the UV absorbance spectroscopy and HPLC. Pseudo first order rate constant of the degradation reaction was calculated by the Langmuir-Hazelwood kinetic model. In addition, probe molecule mineralization was evaluated by TOC analysis. The ZnO/WS2 nanohybrid catalysts durability was analyzed by subjecting it to four repeated photocatalytic cycles. After the photocatalysis reaction the catalyst structure distortion was analyzed by the XRD technique.