Graphene oxide and F co-doped TiO2 with (0Â 0Â 1) facets for the photocatalytic reduction of bromate: Synthesis, characterization and reactivity

Graphene oxide (GO) and F co-doped TiO2 (FGT) particles were controllably synthesized using the hydrothermal method. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy (RS), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS) were utilized to characterize the morphologies and properties of the particles. The mechanism of the photocatalytic reduction of bromate by FGT was also discussed. The results show that a narrow band gap for an FGT composite with a cuboid morphology and (0 0 1) facet was found. The transportation of photogenerated electron and the depression of electron-hole pairs recombination were improved by the co-doping of GO and F in TiO2. Moreover, high activity was exhibited in the photocatalytic reduction of bromate. Over 90% of bromate could be removed with a 0.05 g/L dosage of 1.0% F and 0.1% GO co-doped TiO2 composite in 15 min under UV irradiation at an intensity of 26 μW/cm2 and pH of 5.2. A lower pH was favorable for the photoreduction by affecting the adsorption, which was necessary for the rapid removal. In addition to spherical particles, FGT possesses cuboid morphologies with (0 0 1) and (1 0 1) facets, which would help to promote the migration of electrons and inhibit the recombination of photogenerated electron-hole pairs. The results indicate that FGT is a promising material for bromate reduction in water treatment due to its remarkable efficiency and stability.