The Preparation And Properties Of Highly Activity Nano TiO₂ Composite Films

The Nanometer Titanium dioxide (TiO2) is one of the most promising photocatalysts. TiO2 has excellent light photocatalytic activity, hydrophilic-lipophilic property, surface and interface effect, small size effect, quantum size effect and macroscopic quantum tunneling effect, and so on. it is widely applied in coatings, solar cell, antibacterial materials, waste water treatment and self-cleaning materials. In recent years, TiO2 photochemistry and photocatalys is one of the hot area of research. But the TiO2 have some disadvantage in application, as they can only absorb little of the sun-light energy, the photoluminescence exciton compounds mostly, and so on, It is of great significance to endow TiO2 Photocatalyst with a visible-light response. Thus,the solar energy can be utilized as the light source in photocatalitic reaction.Since last decade TiO2 has been endowed with visible-light response by doping with some transition mental ions or mental oxide. Unfortunately,there are some disadvantages for TiO2 doping with mental ions,including thermal instability and easiness from carrier charge recombination center.This thesis is to study the preparation, characterization and catalytic properties.In this papers, nanosized TiO2, ZnO-TiO2, Fe3+/ZnO-TiO2, ZnFe2O4-TiO2, Ag+/ZnO-TiO2 and SWNTs/ZnO-TiO2 powders were prepared by sol-gel process, and nanosized TiO2, ZnO-TiO2 TiO2, Fe3+/ZnO-TiO2, ZnFe2O4-TiO2,Ag+/ZnO-TiO2 and SWNTs/ZnO-TiO2 films were prepared on glass substrates by sol-gel process with spin-coating machine that was design by ourself. Samples were characterized by modern testing means, such as X-ray powder diffraction(XRD),scanning electron microscope(SEM), and determined the chemical composition, the crystal type, the crystal size, element content and film microstructure.The photocataly activity of TiO2, ZnO-TiO2, Fe3+/ZnO-TiO2, ZnFe2O4-TiO2 and SWNTs/ZnO-TiO2 films were compared by the photocatalytic degradation of methylic. The effects of processing parameters on photocatalytic degradation property of TiO2, ZnO-TiO2, Fe3+/ZnO-TiO2, ZnFe2O4-TiO2 and SWNTs/ZnO-TiO2 films were systematically investigated. The result shows that complex ZnO film improve the photocataly activity of TiO2 films, The photocataly activity of nano-composite films which have 10% of ZnO is best. In addition, Doping Fe3+,ZnFe2O4 and SWNTs appropriately Can improve the photocataly activity,When doped amount of Fe3+,ZnFe2O4 and SWNTs is 1%,1.5% and 1%, the film of ZnO-TiO2 has the best photocatalytic activity. The photoinduced lipophilic property of TiO2, ZnO-TiO2 and Ag+/ZnO-TiO2 film obtained were investigated by H2O and C6H6. It is found that H2O and C6H6 drop's contact angle became small when they were irradiated by ultraviolet radiation. It is indicated that TiO2, ZnO-TiO2 and Ag+/ZnO-TiO2 film possess high photoinduced hydrophilic-lipophilic property, Doping ZnO and Ag+ appropriately Can improve the hydrophilic-lipophilic property,which have 6% of ZnO and 1% of Ag+ is best,The contact angle is 2°and 1°between TiO2-ZnO film and H2O(C6H6).