Stability of the photocatalytic activity of TiO₂ deposited by reactive sputtering

The photocatalytic activity and stability of TiO₂ thin films deposited by reactive sputtering were evaluated through many cycles of aqueous methylene blue solutions photodegradation. Tests were performed in TiO₂ films deposited onto silica, silicon, and lanthanum aluminate substrates under UV light irradiation. The dye degradation was determined using the optical absorbance spectra at preestablished exposure times. After 16 cycles of reaction, 180 minutes each, no systematic losses in the photocatalytic activity were observed in the samples. The best activity was observed on films deposited onto silica glass. The results indicate that the TiO₂ samples deposited by the sputtering technique are stable concerning the UV degradation of methylene blue. (author)