Photocatalysis properties of Pt doped TiO2 film

Pt-doped titanium dioxide (TiO2) thin films were prepared on glass substrate by sol-gel method and spin coating process and their photo-catalytic mechanisms were discussed. The content of Pt in TiO2 powders and films varied from 0.2 wt% to 1.0 wt%. Film samples were heat-treated at 823 K for 2 h. Structure and phases of the Pt-doped TiO2 films and powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy(TEM). The photo-absorption of the all catalysts were tested by UV-vis spectrophotometer. Photo-catalytic activities of the films were evaluated by photo bleaching methylene blue (MB) solution under UV light irradiation. The experimental results indicate that the prepared films are anatase type. The average size of particles in the films is 20~40 nm. For 0.2 wt% Pt-doped catalyst, its absorption edge shifts towards longer wavelengths, which is from 350 nm to 400 nm. Methylene blue aqueous solution degradation rate is 1.6 times of that of the pure titanium dioxide under UV irradiation for 6 h.