Photocatalytic Properties of Columnar Nanostructured TiO2 Films Fabricated by Sputtering Ti and Subsequent Annealing

Columnar nanostructured TiO2 films were prepared by sputtering Ti target in pure argon with glancing angle deposition (GLAD) and subsequent annealing at 400°C for different hours in air. Compared with sputtering TiO2 target directly, sputtering Ti target can be carried out under much lower base pressure, which contributes to obtaining discrete columnar nanostructures. In the present study, TiO2 films obtained by annealing Ti films for different hours all kept discrete columnar structures as the Ti films deposited in GLAD regime. The longer the annealing time was, the better the phase transition accomplished from Ti to TiO2 (a mixture of rutile and anatase), and the better it crystallized. In addition, those TiO2 films performed photocatalytic decolorization effectively and showed a law changing over annealing time under UV light irradiation towards methyl orange, which demonstrated the potential applications for treatment of effluent.