[Comparative studies on the spectral behavior between SO4(2-)/TiO2 and TiO2 photocatalysts]

The differences of spectral behavior between SO4(2-)/TiO2 and TiO2 photocatalysts were studied by using IR, Raman as well as UV-Vis diffuse reflectance spectroscopy(DRS). The results showed that both L and B acid sites exist on SO4(2-)/TiO2 photocatalyst while only L acid sites on TiO2 photocatalyst. As compared with unmodified TiO2, the sulfated TiO2 (SO4(2-)/TiO2) exhibits higher resistance to crystal phase transition from anatase to rutile, higher resistance to growth of crystal grain. As the results of sulfation, SO4(2-)/TiO2 samples possess higher anatase content, smaller crystal grain, and the blue-shifted band edge of adsorption spectra, which increases the optical absorption threshold value and yield larger redox potential.