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.