Photodecomposition of methylene blue over Dy3+ impregnated MAO TiO2 films

TiO2 films were formed in phosphate-based electrolyte on pure titanium by micro-arc oxidation (MAO) technology. After that, they were impregnated with Dy3+-containing electrolyte to produce TiO2:Dy3+ composite films. Effects of the duty cycle, impregnation time and concentration on physical and chemical properties of TiO2 and TiO2:Dy3+ composite films were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). A UV-VIS spectrophotometer was used to study photocatalytic properties of both films. XPS results revealed that Ti 2p spin-orbit components of the TiO2:Dy3+ composite film are shifted towards higher binding energy, with respect to the TiO2 film, suggesting that some of the Dy3+ ions are incorporated into TiO2 lattice. The TiO2:Dy3+ composite films showed an obvious enhanced photocatalytic activity than that of the TiO2 film under UV-irradiation.