Photocatalytic activity enhancement of TiO2 films by micro and nano-structured surface modification

Titanium oxide thin films were deposited by spin coating using a precursor solution of titanium oxide (IV) acetylacetonate. To increase the contact surface area of the films, TiO2 microspheres were added to the surface of the films. These spheres were 2 μm in diameter and formed agglomerates on the surface. They did not spread uniformly across the substrate, creating different roughnesses and morphologies along the surface of films. Photocatalytic properties of the samples were tested by the degradation of a methyl orange solution. The degradation performance was compared between plain films, films with microspheres and films covered with commercial TiO2 P25 powder. The results indicate that the samples that were surface modified with TiO2 microspheres present a photodegradation reaction rate 62 times higher than that obtained for plain TiO2 films. The rate of reaction of the samples covered with P25 was 2 times greater than that obtained for the samples with microspheres, but the adhesion to the film was better in the case of microspheres. Moreover, samples with microspheres could be reused several times maintaining the same structural and photocatalytic properties.