Characteristics of doped TiO2 photocatalysts for the degradation of methylene blue waste water under visible light

Fe-doped, N-doped, (Fe,N)-codoped and undoped TiO2 were prepared by a hydrothermal treatment, followed by a calcination process, using TiOSO4, CO(NH2)2 and Fe(NO3)3 as raw materials. The samples were characterized by XRD, XPS, TEM, PL, FT-IR and UV-Vis diffuse reflectance spectra. Photocatalytic experiments were carried out by decomposition of methylene blue aqueous solution under visible light. It was found that as-prepared TiO2-based catalysts were single phasic anatase titania. Among these samples, the N-doped TiO2 exhibited the better photocatalytic activity. The relations of their photocatalytic activity, spectroscopy properties and band gap structures have been discussed while ab initio calculations of electron structure and density of state (DOS) were done by DFT quantum chemistry method.