Characterization and performance study of GR/ZnWO4 and MoS2/ZnWO4 nanocomposite photocatalysts

Photocatalysts with different composite contents were successfully prepared by hydrothermal synthesis. The variation in molar concentrations of GR and MoS2 changed the photocatalytic properties of the ZnWO4 as the base material composite photocatalysts. Comparison of the photocatalytic properties of the composites at different doping concentrations was made, and characterization analysis of as-obtained samples was realized through XRD, TEM, and ultraviolet-visible (UV-vis) spectrophotometer. The results indicate that the GR/ZnWO4 composite exhibits a fine rod-like structure, with the thinnest nanorods at 15 nm in diameter when GR is compounded at 4%. The MoS2/ZnWO4 composite has a homogeneous lamellar morphology. The highest catalytic activity is achieved when the GR and MoS2 are compounded at 4%, with the MB degradation rate of 98% and 97%, respectively. The GR/ZnWO4 composite and MoS2/ZnWO4 composite nano-photocatalyst have strong absorbance of both UV and visible light, but the GR/ZnWO4 composite photocatalyst has a significantly better absorption range for visible light than the MoS2/ZnWO4 composite photocatalyst. Compared with pure ZnWO4, the band gap of ZnWO4 composites is greatly reduced.