Single-step preparation, characterization and photocatalytic mechanism of mesoporous Fe-doped sulfated titania

Mesoporous Fe-doped sulfated titania photocatalysts were prepared by one-step thermal hydrolysis of industrial titanyl sulfate and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and N2 adsorption–desorption techniques. The effects of the m(Fe)/m(TiO2) on the structures of the titania photocatalysts were investigated. The photocatalytic activity of the mesoporous Fe-doped sulfated titania catalysts was evaluated using the photooxidation of methylene blue in aqueous solutions under UV light irradiation. The results indicated that Fe3+ substitutes Ti4+ in titania lattice, which induced the formation of oxygen vacancies. The oxygen vacancies are favorable to the dissociation adsorption H2O and formation of surface hydroxyl group. Fe3+ captures the photoinduced electrons or holes that are conductive to the efficient separation of the photogenerated carriers, but too many doping Fe3+ will promote recombination of the photogenerated carrier. Sulfur species in the form of sulfate are incorporated into the network of TiOTi and coordinated to titania in bidentate model, resulting in the strong inductive effect, large specific surface area, and mesoporous structure. All these are beneficial to improve the photocatalytic activities of the mesoporous Fe-doped sulfated titania photocatalysts.