Photocatalytic Activity of Titanium Oxide – Iron Oxide Coatings Prepared by Plasma Spraying

This study examines the photocatalytic activity of coatings produced by atmospheric plasma spraying (APS). The spraying tool used is a water-stabilized plasma gun WSP. The TiO2– Fe2O3 powder with and without Na2SiO3 additive was agglomerated to build particles suitable for feeding into the plasma jet and spraying. The coatings are analyzed by scanning electron microscopy, X-ray fluorescence and X-ray diffraction. Photocatalytic degradation of acetone as well as the growth kinetics of the products - carbon dioxide and carbon monoxide - is quantified for both coating types and compared with a pure TiO2 coating. The coatings show a lamellar structure, as is typical for this technological process. However the porosity is rather high. Anatase titania from the feedstock powder is converted to rutile phase whereas a presence of FeTiO3 is detected in the coating without Na2SiO3. The coating from powder with Na2SiO3 admixture is amorphous. Both coatings are more photocatalytically active than the reference TiO2 coating.