Electric And Magnetic Fields Auxiliary Of Tio <sub> 2 </ Sub> Photocatalytic Performance

With the advancement and development of modern industry, increasing environmental problems are brought out. There are many methods for disposing contaminations, among which the multiphase photocatalysis for the degradation of contaminations is superior. This method has high activity, no selectivity, complete oxidation, sunlight and oxygen's application. It can be applied for hard degradation. This technology has been used for environmental protection in American, Japan and Canada. But from to now, the research level of this technology is limited in the laboratories in China.The purpose of this thesis is to improve the photocalytic properties of nano-titania films. Studied the microcosmic mechanism of rear earth doped nano-titania films by using various kinds of experiment means, such as doping and assisting by electric field or magnetic field, in order to find the essence reason which confine the photocalytic properties and offer theoretical and experimental bases for the design and preparation of photocalysis. This thesis includes four parts:1. TiO₂ thin film and doping TiO₂ thin films(Fe³⁺/ TiO₂,La³⁺/ TiO₂,Ni²⁺/ TiO₂,Cu²⁺/ TiO₂) were prepared by sol-gel in glass substrate, and were characterized by XRD, AFM, TG and FT-IR.2. The photocatalytic degradation of methyl orange under UV-ray and electric field with titanium dioxide thin films was investigated in this work, the electric field effects on the photocatalytic properties of TiO₂ nanometer films and the best active lays of TiO₂ were discussed respectively.3. The photocatalytic activities of doping TiO₂ films were tested on the degradation of Azocarmine B, the effects of magnetic field on the photo-catalytic degradation with Fe³⁺/ TiO₂,La³⁺/ TiO₂,Ni²⁺/ TiO₂,Cu²⁺/ TiO₂ and TiO₂ films were investigated.4. The experimental phenomenon is analyzed and the model is established in this work.The results show that the effects of applied magnetic field or electric field on the activity of photocatalyst. The degradation efficiency of methyl orange can be greatly increased by applying the electric field, the growth rate reaches 50 % when the 30 voltage acting on the catalyst; The electric field changes, in certain degree, the best active lays of TiO₂ from 6 to 7. The results indicate that the photo-catalytic activity of Fe³⁺/TiO₂films are deactivation and the activity of La³⁺/TiO₂ films are reactivation under magnetic field. The degradation rate of Fe³⁺/TiO₂ films less than 2.0 % under 0.7×10^-2 T magnetic induction. The degradation rate of doped La³⁺/TiO₂ (1.0 %) film achieves 47. 4% under 3.0×10^-2 T magnetic induction, which is more than 12% compared with that without applied magnetic field. Theoretical analysis indicates that the effect of permanent magnetic field on the photo-catalytic activity of doped TiO₂ films is determined by the doping ion's magnetic permeability and the magnetic intensity.