The Preparation of Rutile TiO₂ Doped with Rare Earth Metal Ions, Sulfur and Their Photocatalytic Properties

Small quantities of lanthanum, yttrium and sulfur are doped in rutile n-TiO2 that was synthesized by an in-situ hydrothermal method. Their photocatalytic activities are characterized by the degradation of methylene blue (MB) under UV-Vis and visible light irradiation. The results show that lanthanum and yttrium ions are rich on the particle surface, which not only makes the surface energy decrease but also inhibits the recombination of photoexcited carriers, while S-doping produces states in the band gap of TiO2 that absorb visible light. Compared to the S-doping, La-doping, and Y-doping, respectively, the synergistic effects of (S, La)-codoping and (S, Y)-codoping result in a higher photocatalytic activity under visible light irradiation.