Preparation, Structure And Property Of Titanium Dioxide/Polyaniline Composite Particulate Materials

More attention has been paid to polyaniline(PANI) improving anatase TiO₂ photocatalysis activity because of its important significance and practically applied foreground.In this thesis, TiO₂/PANI composite particles were prepared by chemical oxidation in situ polymerization. The resulting composite particles structure and properties were characterized by X-ray diffraction (XRD), transmission spectrum (TEM), infrared spectrum (IR), UV-VIS spectrophotometer, X-ray photoelectron spectroscopic analysis (XPS), laser particles size analyzer, thermogravimetric analyzer (TGA) and so on. Photocatalysis activities of different kinds of composite particles were measuredThe results showed that different prepared conditions of aniline content, oxidant kinds and concentrations, dopant kinds and concentrations, prepared temperature and time had important effect on composite particles structure and morphology. The dispersion of composite particles was better than TiO₂ particles. TiO₂ crystal type did not change in the prepared process. Infrared spectrum (IR) showed that intensive interaction (hydrogen bond and coordinate bond) existed between TiO₂ particles and polyaniline. Theory of TiO₂/PANI composite particles prepared by chemical oxidation in situ polymerization was put forward. In the polymerized process, interaction between TiO₂ particles and aniline monomer led to aniline adhering to the surface of TiO₂ particles. Polymerization was taken place on the surface of TiO₂ particles and HCl solution. Polyaniline polymerized in the solution could adhere to TiO₂ particles. So TiO₂/PANI composite particles were prepared.UV-VIS spectrophotometer showed that composite particles decreased the absorbance of ultraviolet and increased the absorbance of visible light, and theirs absorbance border shifted to longer wavelength, which showed that its band gap narrowed. Relationship between different structures levels of TiO₂/PANI composite particles and optical property, protons absorbance were discussed. Better dispersion of composite particles increased the surface of receiving abundant illumination and improved the absorbance ability for photons of surface. Doped polyaniline increased the absorbance for visible light. Hydrogen bond and coordinate bond of composite particles interface made it easy of energy transfer when it absorbed photons. Electron structure decided its energy levels transition.The result also showed that the composite particles photo catalysis activities were improved at a certain extant when they degraded phenol, methyl orange, and 2-naphthol. The rates of photo catalysis degradation accorded with L-H dynamics equation. TiO₂/PANI composite particles changed the absorbance for light and the re-combination ratio of electron-hole reduced, the oxidation of holes increased, the photo catalysis activity of composite particles was improved.