Reduced graphene oxide (rGO) decorated TiO2 microspheres for visible-light photocatalytic reduction of Cr(VI)

A series of reduced graphene oxide (rGO) decorated microspherical titanium dioxide (TiO2) composites were successfully synthesized by two-step hydrothermal method. The structure and morphology of the TiO2-rGO samples were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller specific area analysis, and UV-vis spectrophotometer. The results show that the well-dispersed TiO2 microspherical particles were loaded on rGO nanosheets. The photocatalytic activities of the synthesized composites were measured for the reduction of Cr(VI) under visible light irradiation, which is strongly affected by the concentration of rGO in the composites, with the best photocatalytic reduction of Cr(VI) observed for the composite of 5 wt% rGO decoration. The enhanced photocatalytic activity was mainly ascribed to the extended wavelength region of TiO2, higher specific surface area, and the quick transfer of electrons from excited TiO2 particles to rGO nanosheets with rGO decoration in the composite.