Study On The Preparation And Application Of Nanometer TiO₂ Composite Material

The effect of the method and preparation of nanometer TiO₂ composite materials on their quality and their application is the studied focus in recent years. In the dissertation, several composite models that can enhance their catalytic quality is designed according to photocatalytic mechanism of TiO₂.Several composite materials from the model were fabricated to study the influence of oxidized quality, photocatalytic quality , antibacterial quality. The application in the field of photocatalyst, antibacterial material and smoke composition were also studied. The dissertation is mainly discussed as follows:The oxidizer dopant model, oxidizer dopant-metal deposition model and semiconductor-oxidizer composite model are proposed to fabricate composite materials to expand optic respone band of TiO₂ and reduce the recombination probability of electron-hole pair.According to the oxidizer dopant model, nanometer TiO₂-WO₃ composite photocatalyst were prepared. Photocatalytic degradation experiments for 3.3×10^-3 mol/L formaldehyde solution were performed to inspect the influence of different condition on photocatalytic activity. Fe³⁺/TiO₂ was prepared to study its catalytic activity for methyl orange in sunlight. Cu²⁺/TiO₂ was prepared to study its antibacterial quality. Nanometer V₂O₅/TiO₂ composite material was prepared by wet-impregnation method to study its antibacterial quality and visual light catalytic activity. The experiments result show that the doping of tungsten oxide can resist the growth of crystal size at the same calcining temperature, the mass percentage of rutile phase and the crystal size increase with the rise of calcining temperature. The composite's catalytic activity is highest when the doping of tungsten oxide is 3%, calcining temperature is 600°C, and the content of rutile is 13.5%, the degradation ratio for formaldehyde was 64% after 1.5h which is 79.4 higher than the activity of pure nanometer TiO₂. Fe³⁺/TiO₂ composite material has porous structure, the addition of surfactant CTAB and Fe³⁺ can resist the growth of crystal size. The photocatalytic activity of the composite material is the best when the mass percentage of CTAB is 5%, the doping content of Fe³⁺ is 2%,the pH of the methyl solution is 5. The degradation rate is more than 30% after 3 hours' sun-shining, the photocatalytic efficiency of TiO₂ is enhanced 10 times. Cu²⁺/TiO₂ has better antibacterial quality when the dopant content is more than 1.6%. Its antibacterial mechanism is photocatalysis in proper doping and contacting mechanism in too much dopant. V₂O₅/TiO₂ has excellent antibacterial activity without UV irradiation, it has clear antibacterial circle toward E.coli and S.aureus, the radii is from 11 to 15 mm . FT-IR and XPS results show that there is new Ti-O-V valence in the material. Catalytic degradation rate of formaldehyde was enhanced in visual light when proper doped, V₂O₅ was clustered on the surface of TiO₂ when too much V⁵⁺ was doped,the catalytic activity was fast reduced and has not any antibacterial activity.According to the oxidizer dopant-metal deposition model, nanometer Ag/TiO₂ composite materials were prepared by Sol-gel method and their antibacterial and photocatalytic activity were studied. They were characterized by XRD, TEM and XPS. Experimental results show that the composite materials have excellent antibacterial activity...