Effect of Annealing Temperature on the Photocatalytic Activity and Hydrophobic Property of TiO2 Nanorod Arrays Prepared by Hydrothermal Method

TiO2 nanorod arrays (TNRs) films were fabricated on the polished Ti substrates using hydrothermal and then annealed for 2 h in air at 300°-500°C. The films were characterized by XRD and FESEM. The photocatalytic activities to degrade methylene blue (MB) in solution were determined, expecting these activities to correlate with the hydrophobic property. The experiment showed that rutile peaks recrystallized at the annealing temperature, with the crystallinity increase with increasing annealing temperatures. The TNRs films annealed at 500 oC had a comparatively high crystallinity of rutile phase as well as the highest photocatalytic activity of the films prepared. Surface wettability was studied by measuring the contact angle of the liquid interface which showed hydrophobic nature as water contact angles were greater than 120°. The results can be concluded that as-prepared TNRs film was annealed at 500 oC exhibits excellent hydrophobicity for water molecules and the highest photocatalytic activity on the degradation of MB under UV irradiation.