One-pot hydrothermal synthesis of ZnS–reduced graphene oxide composites with enhanced photocatalytic properties

Abstract

A simple route for the preparation of ZnS–reduced graphene oxide (RGO) composites via a one-pot hydrothermal synthesis is achieved. The chemical composition, morphology and structure of the ZnS–RGO samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption–desorption specific surface area analysis (BET) and diffuse reflectance absorption (DRS). The results show that the ZnS nanoparticles were well dispersed on the RGO nanosheets which serve as the ZnS nanocrystal growth support and the morphology controller. It was found that the specific surface area of the ZnS–RGO composites increased with the incorporation of RGO. The ZnS–RGO composites were used as photocatalysts for the degradation of methylene blue (MB) under UV light irradiation. The results show the ZnS–RGO composites exhibited better photocatalytic activity and photodegradation kinetics compared with pure ZnS and commercial TiO₂ (P25) which is attributed to the high specific surface area and the hindrance of electron–hole pair recombination of ZnS due to the RGO incorporation. Therefore, the RGO has a positive effect on the ZnS–RGO composite as a photocatalyst.