Microstructure and photocatalytic property of TiO2 and Fe3Â +:TiO2 films produced by micro-arc oxidation

First, the TiO2 films prepared by micro-arc oxidation (MAO) were formed in phosphate based electrolyte on pure titanium; after that, they were impregnated with Fe3 +-containing electrolyte to produce the Fe3 +:TiO2 composite films. Effects of the applied current density and impregnation time and concentration on physical and chemical properties of TiO2 and Fe3 +:TiO2 composite films were investigated by Scanning electron microscopy (SEM), stereoscopic microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDS). A UV-vis spectrophotometer was also used to study photocatalytic properties of both films. It is indicated that the film formed in phosphate-based electrolyte were composed of anatase phase with varying fraction depending on the applied current density. XPS results revealed that Ti2p spin-orbit components of Fe3 +:TiO2 composite films are shifted towards higher binding energy, with respect to TiO2 films, suggesting that some of the Fe3 + ions are incorporated into TiO2 lattice. Photocatalytic activity of the films was studied by measuring the degradation rate of methylene blue on their surface under simulated sunlight irradiation. The Fe3 +:TiO2 composite films showed an obvious enhanced photocatalytic activity than the pure layers under UV-irradiation, while their photocatalytic degradation was much higher than that of the TiO2 film under the irradiation.