Photocatalytic Activity Studies of La-Doped TiO2 Thin Films Prepared by Magnetron Sputtering

TiO2 is environment-friendly photocatalytic material that can be used to remove organic pollutants. The previous research showed that doping rare earth elements into TiO2 (REE-TiO2) can enhance the photocatalytic activity of TiO2. In this paper, we have prepared La-doped TiO2 (La-TiO2) films on soda–lime–silicate glass substrates by magnetron sputtering. The film’s photocatalytic effect was demonstrated by the degradation rate of rhodamine B solution, and we operated it with a self-made photocatalytic test chamber. The XRD result shows that the La-TiO2 film is amorphous. When the La target sputtering power was set at 100 W, the Ti target sputtering power was 120 W, the oxygen flow rate was 20 sccm and the deposition time was kept for 4 h, the degradation rate of rhodamine B solution reached 84.49% within 90 min illumination, and 98.59% after 120 min illumination. In addition, the visible light transmittance of La-TiO2 film has reached more than 80%. The film’s UV–visible absorption spectrum indicates that doping lanthanum element has reduced the optical band gap of amorphous TiO2. And the light absorption peak of amorphous La-TiO2 is extended to the visible region with respect to pure TiO2 films, which is beneficial to the La-doped TiO2 film’s photocatalytic efficiency.