Graphene wrapped BiVO4 photocatalyst and its enhanced performance under visible light irradiation

Graphene wrapped BiVO4 (GW-BiVO4) photocatalyst is successfully synthesized via facile sol-gel method and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques. The morphology of GW-BiVO4 looks like a human embryo embedded inside the amniotic sac. The photocatalytic performance of GW-BiVO4 for the decolorization of methylene blue is investigated. GW-BiVO4 system reveals enhanced photocatalytic activity for degradation of methylene blue in water under visible light irradiation as compare to pure BiVO4 catalyst and BiVO4 decorated on graphene sheet (GD-BiVO4). The experimental result shows that the wrapping of the graphene sheets in this composite catalyst enhances the photocatalytic performance under visible light. This enhance activity is mainly attributed to the effective quenching of the photogenerated electron-hole pairs which confirmed by photoluminescence spectra. Trapping experiments of radicals and holes were performed to detect the reactive species generated in the photocatalytic system, experimental results found that the direct hole oxidation reaction is obviously dominant during the photocatalytic reactions on the GW-BiVO4 system.