Preparation, Characterization And Photocatalytic Activity Of Nonmetal Doped Titania Nanotubes

Recently, titania nanotubes have attracted much attention, because they have potential applications in photocatalysts, sensors, solar cell batteries, H2 storge materials. However, the wide band gap (3.87eV, only absorbing the UV region ) and the easy recombination of photoinduced electrons and holes result in a low efficiency of photocatalysis and limit the practical application of titania nanotubes as photocatalyst. In order to efficiently utilize the solar energy, it is necessary to develop a visible-light active phtocatalyst. Transition metals, noble metal deposition, dye sensitizers, nonmental doping are developed to improve the photocatalytic performance of TiO₂ nanoparticle. Because there are very few reports about titania nanotubes's visible light sensitizing and photocatalytic activity, which have high BET surface area, in this article a wet chemical method was developed to prepare the C and N doped titania nanotubes. The composition, structure and properties of these nonmetal doped titania nanotubes were investigated by TEM, XRD, XPS, FT-IR, UV-Vis spectroscopy and Raman spectra. The photocatalytic activity was evaluated by degradation of methylene blue under UV-Vis irradiation.Firstly, TiO₂ nanotubes were prepared by hydrothermal method, the effect of calcining temperature and time on the structure and morphorlogy was studied. It was found that the sample calcined at 400℃for one hour can enhance the crystility and hold the tubular structure.The sample of N-TiO₂ nanotubes prepared by wet chemical method are interstitial doping, The wet chemical method ws emplyed to prepare the N-TiO₂ nanobes using TiO₂ nanotubes as source.The results reveal that N atoms are interstitial doping of N-doped titania nanotubes,not substituent the oxygen of TiO₂, the isolated N2p state can narrow the band gap of titania nanotubes and improve the photocatalytic activity.Secondly, the wet chemical method was also employed to prepar C-doped titania nanotubes. The composition and structure were characterized. The results reveal that the carbon atoms could form a mixed layer of deposited active carbon and carbonoxide species on the surface of TiO₂, active carbon on the surface of titania nanotubes, which can act as a role of photosensitiser like the organic dyes and extent the region of visible light absorption and photocatalytic activity under UV-Vis irradiation was enhanced.Last, preparation, characterization and photocatalytic activity of C-N-TiO₂ nanotubes and N-F-TiO₂ nanotubes were explored.