Research On Preparation And Photocatalytic Performance Of The Doping Nano TiO₂ Powder And The Nano TiO₂ Film

Under the ultraviolet illumination, the nano TiO₂ photocatalyst can degrade the major organic pollutant. In the pollution governance, especially in the sewage governance, it has the attractive prospect, so a lot of countries have focused on it in recent years.The nano TiO₂ powder and the nano TiO₂ film loading on glass has been prepared by sol - gel with Ti (OC₄H₉)₄ as the precursor in this article. It has studied the crystal transition of the nano TiO₂ powder under different calcining temperature. The crystal transition temperature and the crystal grain size has been analysed by XRD and TEM. By means of photocatalytic experiment, photocatalytic activity of the nano TiO₂ has been discussed by illumining time, catalyst amount, and acidity. The results indicate that single-doping V⁵⁺, Ag⁺ can increase the transition temperature of TiO₂, single-doping La³⁺ can't change the transition temtemperature, double-doping V⁵⁺ and Ag⁺ or V⁵⁺ and La³⁺ can increase transition temperature; the illumination time, catalyst amount, acidity all change photocatalytic activity of the nano TiO₂; the extend of illumining time, the increase of catalyst amount, the increase of acidity all increase photocatalytic activity to different extent;the degrading rate of different catalysts to the methyl orange as follows:TiO₂/V-Ag > TiO₂/Ag > TiO₂/V-La > TiO₂/La > TiO_<sub>2/V > Pure nano-TiO₂ Because the fixation catalyst is easier than the powder catalyst in the actual pollution governance, so nano-TiO₂ film photocatalyst has been prepared by sol-gel technique on the glass. The quality of film has been studied by the amount of water and template, the increasing temperature rate and other aspects. Composition and the morphology of film have been characterised by XRD and SEM. The results indicate that TiO₂ which loading on glass is the anatase when the heat treatment is 500°C (2h); the hole size of film is not the linear distribution when the amount of water increase,the maximum hole size of film is at n(H₂O)/n[Ti(OC₄H₉)₄]=3. Proper addition of PEG can decrease the crack;the increasing temperature rate too fastly can influence the quality of film, high quality film can be prepared at 1～2°C/min of increasing temperature rate. Degrading effect is obvious under acidity to methyl- orange.