Structure and Photocatalytic Activity of Silicon Doped TiO_2 Photocatalysts Under Visible Light

TiO2 photocatalysts(TiO2-xSi) doped by different contents of silicon were prepared by a sol-gel method.The catalysts exhibited a higher photocatalytic ability than the pure TiO2 and N-doped TiO2(TiO2-N).The samples were characterized by XRD,XPS,FT-IR and UV-Vis diffuse reflectance absorption spectra.It was revealed that the doped silicon ions formed Si—O—Ti structures on the surface of TiO2 particles.And thus,surface state energy attributed to the silicon dopant was located at 0.2—0.6 eV below the conduction band of TiO2,which enhanced the response to the visible light and photocatalytic ability.It was discussed the suppression to the formation of rutile phase and the growth of titanium dioxide crystals because of the doped silica in TiO2 particles and the effect of catalysts′ surface area and surface species such as hydroxyl to the photocatalytic activity.