Preparation Of TiO₂/Ti Composite And Its Photocatalytic Activity

As an important semiconducting material, Titania has been widely used in the field ofphotocatalytic degradation of organic contaminants. In this paper, TiO₂nanotubes wereprepared by anodic oxidation method，and the influence of oxidation voltage, oxidationtime and the calcination temperature on the morphology of TiO₂nanotubes were studied.Combining with FSEM, XRD testing methods, the structure and morphology of TiO₂nanotubes were analyzed. In the electrolyte of0.5wt%HF, at oxidation voltage of25V,oxidation time at50min, calcination temperature of500℃， the morphology andphotocatalytic character of TiO₂nanotubes were best. The TiO₂nanotubes were restoredby the sol and the result of FSEM showed it’s a good way to make the nanotubes perfect.The catalytic activity of TiO₂nanotubes for the degradation of methyl orange wasdiscussed under different experimental conditions, the experimental results indicated thatwhen initial concentration of methyl orange at5mg/L,the solution pH of1.0, the biaspotential of0.5V, the UV photoelectrocatalytic degradation rate reached91.2%after3hlater. The repeated experiment also showed that the TiO₂nanotubes prepared had excellentphotocatalytic activity and useful life. The electrochemical impedance spectra was used toinvestigate the proccess of the degradation under the conditions of dark, UV light, UVlight with a bias potential. The results showed the system impedance was minimal and thephotocatalytic efficiency of TiO₂nanotubes was very high in UV light and bias potentialcondition.The Ag-doped TiO₂nanotubes were prepared by sol-gel-immersion process, and thesamples were studied by FSEM, XRD and UV-VIS. It was concluded that there was Agon the surface of TiO₂nanotubes indeed, the absorption of Ag-doped TiO₂in the UV lightdistrict was strengthened and the band edge moved to longer wavelength obviously.RuO₂-doped TiO₂nanotubes were prepared by the electro-deposition method, resultsof the test showed that the catalytic activity of RuO₂-doped TiO₂was strengthened in thevisible light comdition.