Preparation and properties of co-doped TiO2 with assistance of ionic liquid

Co-doped mesoporous TiO2 photocatalysts were prepared by an ionic liquid 1-butyl-3-methylimida-zolium tetrafluoroborate ([C4MIM]BF4) modified Sol-Gel method. The effects of Co doping on the surface area, crystalline phase, chemical binding states and compositions, and absorbance of the Co-doped mesoporous TiO2 photocatalysts were studied by N2 adsorption-desorption measurements (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-Vis diffuse reflectance absorption spectra (UV-Vis DRS). BET analysis showed that Co/TiO2 photocatalyst was mesoporous structure with large surface area. XRD patterns indicated that the Co-doped mesoporous TiO2 photocatalysts was anatase structure. XPS spectra indicated that the Co2+ replaced Ti4+ and entered into TiO2 lattice, which reduced the band gap of TiO2 and thereby extending the light response range to the visible region (UV-Vis spectra). Photocatalytic activity of the Co/TiO2 mesoporous photocatalysts was evaluated by photodegradation of methylene blue (MB) under visible light (λ>420 nm). Co-doped TiO2 exhibited obvious visible light activity for MB photodegradation, and 0.3%Co/TiO2 exhibited the highest photocatalytic activity.