Research On Preparation And Luminescence Properties Of Titania Nanocystals

Transparent, uniform stability of the TiO₂ gel, titania nanocrystals and TiO₂ doped with rare earth(Eu³⁺,Sm³⁺,Yb³⁺,Sr³⁺)nanocrystals was prepared by Sol-Gel route and hydrothermal method, ultrasonic method with Ti(OC4H9)4 as reagent. The kinetic theories were introduced, and the crystalline particles growth apparent activity energy of anatase and rutile phases were calculated, and then the high-temperature thermodynamics processes of anatase-rutile phase transitions were theoretically analyzed, and some excellent reference data were gained. Meanwhile, the huge surface and interface areas were calculated using several experiential formulas. The effects of preparation conditions such as kinds of stabilizer, catalyst, the heat treatment were investigated. The strcucture , morphology, luminescence property and antibacterial property of samples was analyzed and tested by SEM, XRD, PL,UV-vis. The TiO₂ photocatalytic activity was determined by disinfection experiment. Still further, the research work was described in detail as the following aspects:1. The preparation of TiO₂ sol and powder:Homogeneous transparent TiO₂ sol was prepared by sol-gel route using Ti(OC4H9)4 as main starting materials in ethanol solution containing stabilizer, catalyst and surfactant, adjust the value of pH with HNO3 to 2³. Study the gelation time of TiO₂ sol changing with the ratio of water and ethonal, and kinds and amounts of stabilizer and catalyst. Moreover we concluded the best sol-gel process parameters and prepared a series of nano-TiO₂ powders under the different heat treat temperature.2. The structure and properties of nano-TiO₂ powderThe powders strcucture and morphology was inspected using XRD, SEM, the properties of luminescence and catalyst was examined by PL,UV-vis spectrum. The results showed that phase transition temperature (Anatase-Rutile) varied with the different catalyst and stabilizer. The phase transition temperature depended obviously on the kind of catalysts.3. The research of nano-TiO₂(TiO₂/RE)photoluminescence and antibacterial activityAt room temperature, the optical properties which mass materials didn't take on were observed in nanometer titania materials .The effects of photocatalyst preparation conditions on disinfection were investigated, such as heat-treated temperature, the sorts of catalyst, pH of Sol. The results showed that heat-treated temperature and the sorts of catalyst have important influence on the disinfection efficiency becaust they can influence the crystal phase and grain size.The crystal phase, grain size, dispersion and uniformity of grain together determine photocatalytic activity.