Enhanced photocatalytic degradation of azo dye using rare-earth metal doped TiO2 under visible light irradiation

Lanthanum doped TiO2 nanoparticles (La doped TiO2) have been prepared by a sol-gel process using TiO(C4H9)4 as raw material and are characterized using XRD, FT-IR, SEM-EDS, TEM and UV-DRS. The insertion of La ion in TiO2 lattice has been confirmed by SEM-EDS and XRD data. TEM studies have confirmed that La ions are uniformly doped over TiO2 lattice. The band gap level of La doped TiO2 is decreased to 2.92 eV with a red shift due to charge transfer reaction which is confirmed by UV-DRS. The photocatalytic activities of the synthesized nanoparticles are evaluated for the degradation of Congo red dye (20 ppm) in an aqueous solution with La doped TiO2 (0.25 g) at pH= 6.3, under solar light irradiation. The photocatalytic results confirmed that the La doped TiO2 show good photocatalytic activity and can be considered as a promising photocatalyst for the degradation of organic pollutants in water. Due to the stability of La doped TiO2 nanoparticles, it could be reused for more than five cycles reaching 100% degradation efficiency.