Study On Preparation Of TiO₂ Film Modified With Noble Metal And Its Photocatalytic Properties

Nanometer TiO₂ photocatalyst has good photoelectric properties and can absorb ultraviolet of wavelength less than 387nm so that it degradates organo-pollutants in water with photo-catalysis. The TiO₂ photocatalyst could be easily synthesized and has high catalytic activity, lower cost, and worth in environmental pollution. However, because of the hard separation recovery of the TiO₂ catalyst powder, the light energyutilization is not high, limiting the TiO₂ light catalyst technique's application in industry production.In this paper,the ordered porous alumina films as a carrier of TiO₂ were obtained by anodizing, the TiO₂ films are prepared by soak-raise in TiO₂ sol. Photocatalytic performance of TiO₂ was modified by doped precious metals.The influence of the preparation conditions on film quality, structure, size and crystalline was studied by means of XRD, SEM and UV-VIS. The concrete research contents are as follows:1. The preparation of TiO₂ film attached to the anodic alumina surface was studied by sol-gel technique,using tetrabutyl titanate as raw material. The TiO₂ particle can be changed to anatase type by heat treatment at 500℃raw for 3 hours.2. Study on preparation and electrocatalytic activities of the modified TiO 2 film by doping noble metal.The results of XRD,SEM show that the ordered porous alumina films can load TiO₂ effectively and TiO₂ prepared in this experiments was anatase in which was calcined at 500℃,the average size of TiO₂ particals in the film was about several decade nanometer. These also show that M (M=Ag,Au) addition has a suppressive effect on the crystal growth of TiO₂ in calcination. Comparing with the different degradation tests of TiO₂/Al₂O₃ thin film and TiO₂/M/Al₂O₃ thin film at different deposition time,TiO₂/M/Al₂O₃ thin film dopted 10s M behaves better photocatalytic ability, which its degradation ratio is about 80%. It is shown that the amount of M dopants influences the photocatalytic ability of TiO₂ thin film. Electrochemical impedance spectrum (EIS) experiments showed that the influence of substrate bias can improve photocatalysis activity of TiO₂/Al₂O₃ thin film and TiO₂/M/Al₂O₃ thin film in the degradation of methyl orange.