The Research On Photocatalytic Properties And Applications Of TiO₂

In recent years, the research on photocatalytic material Nano-TiO2focuses on doping icon and structure design. Considering the hot spots of studying, the thesis describes a system for the synthesis of mesoporous TiO2(a visible-light driven catalyst) nanoparticles doped by different kinds of particles.The thesis describes a system for the synthesis of Cu-doped mesoporous TiO2and N-doped mesoporous TiO2nanoparticles by a hydrothermal method at relatively low temperatures, employing tetrabutyl titanate as the titanium source, Cu(NO3)2·3H2O and urea as the precursor of the dopant and pluronic P123as the template. The technique used is to dope the as-prepared mesoporous TiO2system with copper and nitrogen. In this method, the copper species with the form of Cu1+, which was attributed to the reduction effect of dehydroxylation and evidenced by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), And it is accepted that doping with non metal ions can better-dispersed into TiO2lattice. Definitely, a visible-light response was obtained by doping ions both metal and non metal.It’s well known, physical properties of semiconductor strongly depended on their nanoparticles size as a result of quantum size effect. In this as-prepared mesoporous TiO2system, original particles with a size of approx.20nm are aggregated together to shapes of approx.1000nm, which resulted in the porous aggregate structure.A discussion of possible reasons for the enhanced photocatalytic activity of composite catalyst under visible light irradiation is summarized as follows:Firstly, the light absorption extended into visible light region due to icon doping. Secondly, the icon doped acted as electron and hole trappers which could effectively reduce the photogenerated hole-electron recombination rate. Finally, the higher adsorption of methyl orange onto the catalyst surface due to the mesoporous structures also played a role in enhancing the photocatalytic activity of composite catalyst.Moreover, the thesis had done some effect on the self-cleaning coating based on the photocatalytic activity of TiO2. A new kind of concept was put forward that using inorganic film-forming material as the dispersion medium of TiO2. In the method, film-forming material can avoid being broken down by the photocatalytic activity of TiO2. It someway fixed up a gap in the domestic research field.