Gd–La codoped TiO2 nanoparticles as solar photocatalysts

Gd–La codoped TiO2 nanoparticles with diameter of 10 nm were successfully synthesized via a sol–gel method. The photocatalytic activity of the Gd–La codoped TiO2 nanoparticles evaluated by photodegrading methyl orange was significantly enhanced compared to that of undoped or Gd or La mono-doped TiO2. Ti4+ may substitute for La3+ and Gd3+ in the lattices of rare earth oxides to create abundant oxygen vacancies and surface defects for electron trapping and dye adsorption, accelerating the separation of photogenerated electron–hole pairs and methyl orange photodegradation. It is believed that the formation of an excitation energy level below the conduction band of TiO2 from the binding of electrons and oxygen vacancies decreases the excitation energy of Gd–La codoped TiO2, resulting in versatile solar photocatalysts. The results suggest that Gd–La codoped TiO2 nanoparticles are promising for future solar photocatalysts.