Research Of Self-cleaning Titanium Dioxide Films By Sol-gel

In recent decades, studies on photocatalysis have attracted considerable attention. Titanium dioxide (TiO2), which is one of the most basic materials in our daily life, has emerged as an excellent photocatalyst material for environmental purification. In this thesis, the history, principle, problems and prospect of the photo induced super-hydropholicity and photocatalytic activity of TiO2 films are reviewed. At the same time, the modifying methods of TiO2 photocatalytic are introduced.Because of the anatase's broad Eg (3.2eV), the absorption thresholds correspond to 380nm for the TiO2. Consequently, only the ultraviolet fraction of the solar irradiation can be active in the photoexcitation processes using pure TiO2 solid. The high recombination rate of Charge carrier and low efficiency of quantization are also the deficiencies of pure TiO2. This thesis is focused on TiO2 films as self-cleaning material. Using hydroxypro-pylcellulose (HPC) as additive TiO2 films, V-doped TiO2 films, Si-doped TiO2 films and co-doped TiO2 films by the sol-gel technique on glass substrates, the hydropholicity and photocatalytic activity were investigated.As to the HPC-doped TiO2 film, it was found that TiO2 films with HPC are composed of smaller particles, and possess higher surface areas and surface roughness. TiO2 films with HPC show better light-induced hydropholicity and higher photocatalytic activity than the films without HPC.The results show the optical absorption by Vanadium ions doped TiO2 films. The presence of Vanadium and Silica in TiO2 greatly enhanced their photo-activity. The reason of the increasing photo-activity was analyzed. It was found that the acidification of water could also improve the photocatalyst.The photocatalyst of V and Si co-doped TiO2 films is improved and the hydropholicity of V and Si co-doped TiO2 films is reduced..