Structural and spectroscopic study of the Fe doped TiO 2 thin films for applications in photocatalysis

In this work we are presenting the results of structural and optical investigations of TiO 2 and Fe doped TiO 2 films using XRD, XPS, UV‐VIS transmittance spectroscopy, and the application of these films in photocatalysis is demonstrated. Fe‐doped TiO 2 films were prepared by sol‐gel method. The concentration of Fe utilized for doping ranged from 0.5 to 4% by atomic weight. For lower concentrations of Fe the transformation from amorphous‐to‐polycrystalline occurred at 400 °C. However, as the Fe concentration was increased to 4% this transformation occurred only after annealing at 600 °C. The average grain size for 4% Fe doped sample was in the range of 13 nm. In the case of pure TiO 2 the XPS analysis showed only the presence of Ti 4+ , where the 4% Fe doped film showed the presence of two species of Ti atoms; one of unperturbed Ti atoms and another of negatively charged surface of Ti atoms due to the interaction with Fe atoms in the anatase lattice of TiO 2 . The optical band gap was found to decrease with Fe concentration. The resistivity was found to decrease by one order after doping. The 4% Fe doped TiO 2 films showed an increased photocatalytic activity. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)