Influence of oxygen flow rate on photocatalytic TiO ₂ films deposited by rf magnetron sputtering

Titanium dioxide (TiO ₂) thin films having anatase (1 0 1) crystal structure were prepared on non-alkali glass substrates by rf (13.56 MHz) magnetron sputtering using a TiO ₂ ceramic target under various oxygen partial pressures. At a fixed substrate temperature of 400 °C and total gas pressure of 1 Pa after 3 h deposition. Effects of oxygen partial pressure on the structural, surface morphology, and photocatalytic activities of the TiO ₂ thin films were investigated. We performed both photoinduced decomposition of methylene blue (MB) and photoinduced hydrophilicity under UV light illumination. The XRD patterns exhibited a broad-hump shape indicating the amorphous structure of TiO ₂ thin films. The results showed that when the [O ₂/(Ar + O ₂)] flow rate increased to 50%, the photoinduced decomposition of MB and photoinduced hydrophilicity were enhanced. The water contact angle after 9 min UV illumination was approximately 4.5°, and the methylene blue (MB) solution decomposition from 12 down to 3.34 μ mol/L for 240 min UV irradiation.