On the photocatalytic activity of lanthanum impregnated TiO 2 films prepared by micro-arc oxidation.

TiO2films were synthesised by microarc oxidation (MAO) process on pure titanium substrate in a phosphate-based electrolyte. Then, La3+/TiO2composite films have been prepared in lanthanum-containing solution by La3+impregnation. Effects of the frequency, the concentration of lanthanum and impregnation time on physical and chemical properties of the films were investigated by SEM, XRD, EDS techniques. A UV-vis spectrophotometre was also used to study optical properties of the layers. Results showed that the photocatalytic activity of TiO2films prepared by MAO was first increased and then decreased with the increasing frequency applied in the experiment. It is indicated that the variation of photocatalytic activity in the TiO2films was affected by the content of anatase. After the La3+impregnation, the photocatalytic activity of La3+/TiO2composite films was greatly improved compared with that of the TiO2films. [ABSTRACT FROM AUTHOR]