AVS 53rd International Symposium
    Applied Surface Science Thursday Sessions
       Session AS-ThP

Paper AS-ThP27
Photocatalytic Decomposition of CH@sub3@OH on TiO@sub2@ Sputter Films Prepared by Changing Ar/O@sub2@ Ratio and Working Gas Pressure

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Aspects of Applied Surface Science Poster Session
Presenter: T. Takahashi, University of Toyama, Japan
Authors: T. Takahashi, University of Toyama, Japan
K. Prabakar, University of Toyama, Japan
T. Nakashima, Kashiwa Chuo High School, Japan
Y. Kubota, University of Yokohama City, Japan
A. Fujishima, Kanagawa Academy of Science and Technology, Japan
Correspondent: Click to Email
TiO@sub2@ has attracted considerable attention as a photocatalyst with strong activity. We found that TiO@sub2@ sputtered films prepared under heavy plasma exposure exhibited good photocatalytic decomposition of CH@sub3@OH. However, the TiO@sub2@ films showed less than perfect transparency because of the slightly opaque surface. For practical use, transparency is desirable. In this study, to deposit transparent TiO@sub2@ films, the substrates were placed at a position removed from the plasma. TiO@sub2@ films were deposited on glass slide substrates. The ratio of Ar to O@sub2@ (G@subR@) were 9:1, 8:2, 7:3 and 6:4. The crystallographic and surface structures and optical properties of TiO@sub2@ films deposited at working gas pressures (P@subW@) ranging from 0.2 to 0.8 Pa were investigated in detail. The decomposition of gaseous methyl alcohol was performed to investigate the dependence of the photocatalytic reactions on the structures and properties of the TiO@sub2@ films. In all of the TiO@sub2@ films, only the A(101) diffraction peak was observed from the x-ray patterns, where A indicates anatase TiO@sub2@. The crystallinity improved greatly with decreasing P@subW@. The transmittances of all of the TiO@sub2@ films were constant at 80-90 % for wavelengths in the range of 900 nm to 380 nm. The as-deposited TiO@sub2@ films successfully photocatalyzed the decomposition reaction of CH@sub3@OH to CO@sub2@ and H@sub2@O, according to the infrared transmittance spectra. The decomposition rate using the TiO@sub2@ films increased with increasing P@subW@. For the TiO@sub2@ films deposited at a P@subW@ value of 0.8 Pa and a G@subR@ value of 2.3, the CO@sub2@ formation rates were about 2.2 times higher than those prepared at a G@subR@ value of 9 for a solar irradiation time of 130 min. In conclusion, the transparent TiO@sub2@ films deposited in this study are quite photocatalytically active, supporting the decomposition of gaseous methyl alcohol.