Influence of La3+ and Pr3+ co-doped on photocatalytic properties of TiO2 nanoparticles

Pure nano TiO2 and La3+-Pr3+ co-doped nano-TiO2(La3+-Pr3+/TiO2) catalyst were prepared by a sol-gel method with TBT and distilled water as forerunner body, ethanol as solvent and glacial acetic acid as inhibitor. The prepared samples were characterized by XRD, TEM and UV-Vis. The UV-light photocatalytic performance of the obtained materials was evaluated by methylene orange decomposition. The results show that the prepared samples are all pure anatase phase nano-TiO2 and their diffraction peak broadens obviously after La3+-Pr3+ co-doped. Compared with pure TiO2, the particle sizes of La3+-Pr3+ co-doped TiO2 are smaller, its specific surface area is larger, and its absorption edge shifts more remarkably towards longer wavelength. The photocatalytic activity of La3+-Pr3+ co-doped TiO2 is higher than that of TiO2 or La3+(Pr3+)-doped TiO2, which is enhanced with the La3+ and Pr3+ contents, reaching the maximum at the La3+/TiO2 and Pr3+/TiO2 molar ratios of 1.0% and 0.2%, respectively. The enhanced visible photocatalytic performance is attributed to the synergetic effect of La3+ and Pr3+ co-doped.