Study On Preparation And Performance Of Multi-functional TiO₂ Film

TiO2 film has wider application in environmental cleanup and preparation of multi-functional materials because of its excellent photocatalytic properties and photo-hydrophility. Multi-functional TiO2 film were prepared on glass by electron evaporating method, colloidal gel route and polymeric gel route. The effect of preparation methods and conditions on the physically chemical properties of TiO₂ film was systematically studied. On the basis of the studies of properties of TiO₂ film prepared by different methods, the best was selected and the factors which influence the photo-hydrophility of TiOi film were studied. The photo-hydrophility were characeterized by contact angle of water on the film. Using oilic acid as model reactant, the photocatalytic properties of TiO₂ film were studied by ATR-FT-IR. Crystal structure, micro-structure and optical properties of TiO₂ film were characterized by XRD, SEM, and UV-Vis. The results showed that preparation methods and conditions have distinct effect on photocatalytic properties and photo-hydrophility of the film. The TiO₂ films, which prepared by electron evaporating method, exhibited compact surface morphology and the visible light transmittance exceeded 65%. When preparation is performed in absence of O2, the film is with amorphous structure and exhibited less photocatalytic properties and photo-hydrophility, and it was prepared in the presence of O2, the film is with anatase structure and exhibited less photocatalytic properties and excellent photo-hydrophility. The TiO₂ films prepared by colloidal gel route showed XRD diffraction of a non-stoichiometric species besides those of anatase, and exhibited excellent photo-hydrophility as well as photocatalytic properties. The TiO₂ film prepared by polymeric gel route only exhibited faintish photo-hydrophility and photocatalytic properties, and surface of the film is incompact and with crack. As a whole, the TiO2 film prepared by colloidal gel route has better photocatalytic properties and photo-hydrophility than those prepared by the others. The photo-hydrophility of polycrystalline TiO₂ film is related with the size of colloid particles, illuminationintensity, measurement environment and temperature. The smaller the size of colloid, the better the photo-hydrophility. The higher the UV light intensity, the better the photo-hydrophility. In addition, the decreased percent of contact angle is directly proportional to UV intensity when it was less than 1.0 mW/cm2. The photo-hydrophility was very sensitive to the measurement environment; which was higher in water vapors than in oxygen.