Studies On The Preparation Of Titanium Dioxide Thin Films And Their Application In Treatment Of Organic Pollutants

TiO2 photocatalyst(for example,Immobilized TiO2,porousTiO2 film,TiO2/Fe3+,TiO2/Fenton,etc.)has a lot of advantages on photocatalytic degradation of organic pollutants in water,such as low energy consumption,simple operation,mild reaction conditions,the reduced secondary pollution.These advantages attractive much attention of researchers.The large numbers of experiments show that the Ti02 photocatalysis has a strong degradation on industrial waste water,especially apply to later deep treatment.However,because of the low catalytic activity and quantum efficiency,so the key is to improve the catalytic property of TiO2 photocatalyst.TiO2 thin films were prepared by two different preparation of the sol-gel and electrochemical anodic oxidation.The photocatalytic degradation performance of these two samples were investigated using methylene blue(MB)as a target pollutant.Using tetrabutyl titanate as precursor,ethanol as solvent,diethanolamine hydrolysis control agent,TiO2 thin films were prepared on titanium substrate and the stainless steel substrate by sol-gel.the crystal changes with heat treatment temperature of prepared Ti02 film was studied by X-ray diffraction(XRD).The photoelectrocatalytic degradation and re-use performance of TiO2 film were studied.The results show that the performance of TiO2 films prepared on titanium substrate is better than the TiO2 thin films prepared on stainless steel substrate.The different heat treatment temperature affects the crystal composition of the film.The film in the heat treatment temperature of 500?shows best photocatalytic performance.The film repeat performance is bad.TiO2 nanotube array films were prepared by electrochemical anodization on Ti surface in fluorine-containing solution.Scanning electron microscopy(SEM)observation showed that the electrolyte composition affect the structure and morphology of TiO2 nanotube array films.The photoelectrocatalytic degradation performance were studied,and compared the differences of electrolysis catalytic,photocatalytic and photoelectrocatalytic degradation.The results showed that TiO2 nanotube array film prepared in the NH4F-H2O-glycol electrolyte performs the best photocatalytic property.After 340min,94.23%MB was catalytically degraded.The results of EIS analyses revealed that the surface reaction step was the only rate limiting step either for the photocatalytic process or for the photoelectrocatalytic process.The extra bias potential could decrease the values of the electron-transfer resistance and increase the separation efficiency of photogenerated electron-hole pairs.