Photocatalytic TiO2 film prepared using arc ion plating

Arc ion plating (AIP) is known to be used in producing high-quality protective films at low deposition temperatures and may also have applications in the production of photocatalytic titanium dioxide (TiO2) films. The success would enable the treatment of less-expensive soda-lime-silica glass, which can become distorted at the high deposition temperatures of other coating processes and as a result of the heat treatments associated with them. In this study, photocatalytic TiO2 films were deposited on glass substrates by an arc ion plating system utilizing a pulsed-DC substrate bias power supply. The deposition time, substrate bias, and oxygen partial pressure were varied in order to determine their effects on the properties of TiO2 films. Photocatalytic performance of the films was evaluated by measuring the transmittance of methylene blue (C16H18N3S center dot Cl center dot 3H(2)O) solution irradiated by ultraviolet light for 30 h. An increase in either the substrate bias or oxygen partial pressure led to reduced deposition rates, which ranged within 6-9 mu m/h for all deposition conditions examined. From X-ray diffraction (XRD) analysis, it was found that the anatase phase quantity of the TiO2 films increased as a result of reducing the substrate bias or increasing the oxygen partial pressure. The photocatalytic activity was found to be more dependent on the anatase phase quantity of the films as opposed to other coating properties such as film thickness. (c) 2004 Elsevier B.V. All rights reserved.