Lanthanide-doped titanium dioxide layers as photocatalysts

Films (∼0.5 mg/cm2) from TiO2 doped with 1–10 mol% Ln3+ (Ln = La or Gd) are deposited on different types of substrates by spray-pyrolysis using ethylene glycol solutions of Ti4+–Ln3+ citric complexes as starting material and O2 as a carrier gas. The films are post-deposition heated at 500 °C. Their phase composition, crystal structure, morphology, sorption ability and photocatalytic activity are studied. Aqueous solution of methylene blue is applied as a model pollutant. A film with 5 mol% La on Ti-coated stainless steel substrate shows significantly higher photocatalytic activity than the best performing samples produced from commercially available titania.