Effect of annealing temperature on the photocatalytic activity of sol-gel derived TiO{sub 2} thin films
- Graduate School of Science and Engineering for Research, University of Toyama, 3190 Gofuku, Toyama 930-8555, Toyama (Japan)
Transparent TiO{sub 2} thin films were deposited on glass substrates by a sol-gel dip coating technique, where crystallinity can be achieved at a relatively low annealing temperature. In this sol-gel preparation technique, acetic acid was used as a catalyst. Repetitive dip coating and drying, with a single annealing has made this technique easier to prepare TiO{sub 2} thin film with desired thickness within a short period of time. The crystallographic and optical properties of TiO{sub 2} films were investigated in detail. The photocatalytic activity was evaluated by the measurement of decomposition of methanol under UV-visible irradiation. The rate of decomposition of gaseous methyl alcohol depends on the structures and surface properties of the TiO{sub 2} films. The structure of the TiO{sub 2} films, prepared at various annealing temperatures, shows different crystallinities. Although crystallinity has been observed for 300 deg. C annealing temperature, it improved with increasing annealing temperature. The average transmittances of the TiO{sub 2} films slightly decrease with the increase of the annealing temperature in the range of 900-380 nm. The optical transmission edge of the TiO{sub 2} films, annealed at different annealing temperatures shifts toward higher wavelength with higher annealing temperature. All the as-deposited TiO{sub 2} films successfully photocatalyzed methanol to CO{sub 2} and H{sub 2}O, measured by Fourier transform infrared spectrometer. The decomposition efficiency of TiO{sub 2} films increased with decrease of annealing temperature. The surface morphology of all the samples was investigated by field emission scanning electron microscopy and atomic force microscopy measurements. The higher photocatalytic activity of the sample prepared at lower annealing temperature was explained by the effect of more porous structure with smaller grains and open surface morphology of the sample.
- OSTI ID:
- 21192382
- Journal Information:
- Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Vol. 26, Issue 4; Other Information: DOI: 10.1116/1.2889416; (c) 2008 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1553-1813
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACETIC ACID
ANNEALING
ATOMIC FORCE MICROSCOPY
CARBON DIOXIDE
DECOMPOSITION
DIP COATING
FIELD EMISSION
FOURIER TRANSFORMATION
INFRARED SPECTRA
INFRARED SPECTROMETERS
METHANOL
MORPHOLOGY
OPTICAL PROPERTIES
PHOTOCATALYSIS
POROUS MATERIALS
SCANNING ELECTRON MICROSCOPY
SOL-GEL PROCESS
SURFACES
THIN FILMS
TITANIUM OXIDES