Low-temperature deposition of anatase thin films on titanium substrates and their abilities to photodegrade Rhodamine B in water

Well-crystallized anatase thin films with various film thicknesses for up to 0.8 μm were deposited on Ti substrates directly from a titanium tetrafluoride solution at a low temperature of 60 °C. The thin film consisted of aggregates of anatase particles with sizes of 10–20 nm, which grew mainly along the [004]-axis. Photodegradation of Rhodamine B in water assisted with the thin films was evaluated. The photocatalytic activity is found to increase with an increasing subsequent calcination temperature for up to 500 °C due to the further improved crystallinity. The removal of fluorine ions from the thin films through heating beyond 300 °C also benefited the photodegradation reaction. The photocatalytic activity of the present thin films increased almost linearly with the increasing film thickness.