Preparation Of Nanometer Crystalline TiO₂ And Its Photo-catalytic Functions

In this paper we reported the preparation of nanometer TiO2 by the methods of hydrolysis and deposition with of TiO2 (H2O) ? a low-cost raw material. The photocatalysis of nanometer TiO2 in the solution and the TiO2 film on the surface of ceramic were discussed. The photocatalytic degradation of PS, PE by the nanometer TiO2 was also studied. The main results are listed as:1.Nanometer Ti02 was prepared by the methods of hydrolysis and deposition. The samples were characterized by XRD, TEM. It is shown the particle size of the TiO2 is 7 22nm by hydrolysis and 12 23 nm by deposition. The crystalline structure of TiO2 is anatase and rutile by hydrolysis. It is anatase even if heated to 800# by deposition. The photocatlysis of the samples was compared with P-25.2.The TiO2 film on ceramic was prepared by adding the TiO2 in organic solution, coating the ceramic plate by dipping-coating it in this solution then heating it. The crystalline structure of TiO2 in the glaze layer was characterized by XRD. The morphology of TiO2 in the glaze layer and the thickness of the TiO2 film were studied by SEM. The photocatalytic activity of the TiO2 film on ceramic was tested through sterilization of E. coli. The results shown: the particles of TiO2 had settled in the inner position of the glaze layer. The TiO2 particles in the glaze layer retain the anatase crystalline. The survival ratio of E. coli decreases to 2% after 4 hours irradiation of room daylight on the TiO₂coated ceramic.3.The photocatalytic effect of nanometer TiO2 particles and the TiO2 film on ceramic on Hepatitis B surface antigen (HBsAg) of hepatitis B virus (HBV) was investigated. The ELISA standard method was used to assess the efficiency of TiO2 material to destroy the HBsAg. The research has shown that the suspension of TiO2 (0.5 g/L) can destroy the most HBsAg under the irradiation of mercury lamp, with light intensity of 0.6 mW/cm2 at 365 nm wavelengths, or under the sunlight for a few hours. TiO2 film on ceramic can destroy the HBsAg under the irradiation of mercury lamp, with light intensity of 0.05 mW/cm2 at 365 nm wavelengths, or under the room daylight for a few hours.4.Metal (Co, Cu, Fe) phthalocyanines and porphyrins modified titanium dioxide, MPz/TiO2,IVMPc/TiO2 photocatalyst were prepared. The photocatalyst FePz/TiO2, FePc/TiO2 reveal enhanced activity for the degradation of organic dye as compared to nonmodified TiO2. The activity of FePz/TiO2 was higher than FePc/TiO2. The organic dye could be degraded by FePz/TiOi photocatalyst under more than 450nm wavelength visible light irradiation. The enhanced activity of FePz/TiO2 is attributed to the cooperative functions of the two components of the photocatalyst, Iron porphyrins and the TiO2 semiconductor in the generation of OH radicals.5. Grafting polymers onto the surface of TiO2 nanoparticles by co-polymerizing of styrene monomer and silicone coupling agent WD-70 was reported in this paper. XPS is used to characterized the chemical bonds Ti-O-Si between the copolymer and the TiO2 nanoparticles. Grafting Ti02 (G-TiO2) nanoparticles can be readily dispersed in toluene, thanks to the steric hindrance effect provided by the polymer on the surface of TiO2.6. A new kind of photodegradable polystyrene (PS)-TiO2 nanocomposite film was synthesized and studied. The TiO2 nanoparticles were modified by grafting polymer on its surface (G-TiO2). The G-TiO2 powders then were dispersed into the monomer of polystyrene (PS), the PS-G-TiO2 composite films were formed through polymerization. The photocatalytic degradation of the composite films was investigated. The as-prepared films were characterized with SEM, GPC (gel permeation chromatogram), FT-IR and UV-Vis spectroscopy, and the photo-induced -weight-loss. The results shown that PS-G-TiO2 nanocomposite films could be efficiently photo-catalytically degraded under UV illumination in air. The weight loss of the PS-G-Ti02 film reached 25.1% under UV-light irradiation for 288 hours, average molecular weight (Mv) reduced to 1/4 of the original mo...