Structures and Photocatalytic Performance of TiO2-FeTiO3 Coatings Prepared by Plasma Spraying Technique

Abstract

FeTiO3 with band gap of 2.85 eV was added into TiO2 powder to improve the visible light responsivity of TiO2 in this study. The compositions and photocatalytic activity of plasma sprayed TiO2, TiO2-30%FeTiO3, TiO2-50%FeTiO3 and FeTiO3 coatings were investigated. The influence of FeTiO3 compound on the charge carrier separation and recombination in the TiO2-FeTiO3 coating was discussed. The FeTiO3 coating plasma sprayed under the arc current of 400 A consisted of rutile TiO2, FeTiO3, Fe2TiO5, and thermally metastable Fe2Ti3O9 and γ-Fe2O3. TiO2-30%FeTiO3 coating sprayed under the arc current of 400 A, which contained anatase TiO2, rutile TiO2 and FeTiO3, had good photocatalytic activity. The relative deposition rate of TiO2-30%FeTiO3 powder under the arc current of 400 A was approximate to 4 μm/pass. For the low band gap of pure FeTiO3 compound, the existence of FeTiO3 could improve the photocatalytic activity of anatase TiO2 when FeTiO3 contacts coherently with it, which was explained using a proposed two-steps electron transfer model.