Thermal and photo-stimulated desorption of chemisorbed oxygen molecules from titanium dioxide surfaces
Thermal desorption (TD) and photo-stimulated desorption (PSD) studies of 18O 2 pre-adsorbed TiO 2 powders have been carried out under high-temperature UHV treatment. At peak temperatures ( T p) 180 and 470 K with a shoulder at about 520 K, 18O 2 TD's are observed. TD of 16O 18O with a small amo...
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| Published in | Surface science letters Vol. 254; no. 1; pp. L433 - L436 |
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| Main Authors | , |
| Format | Journal Article |
| Language | English |
| Published |
Elsevier B.V
01.08.1991
|
| Online Access | Get full text |
| ISSN | 0167-2584 |
| DOI | 10.1016/0167-2584(91)90004-B |
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| Summary: | Thermal desorption (TD) and photo-stimulated desorption (PSD) studies of
18O
2 pre-adsorbed TiO
2 powders have been carried out under high-temperature UHV treatment. At peak temperatures (
T
p) 180 and 470 K with a shoulder at about 520 K,
18O
2 TD's are observed. TD of
16O
18O with a small amount of
16O
2 is observed at 530 K, indicating that oxygen isotope exchange occurs between
18O
2 gas and defective TiO
2 surfaces. By UV illumination with the threshold energy of 3.0 eV,
18O
2 PSD takes place at room temperature, which results in the decrease of an
18O
2 TD peak. PSD rate decays as
t
−
n
with
n about 0.5, where
t is the illumination time. A plausible PSD mechanism is discussed based on the substrate-dependent process induced by photons with band-gap energy. |
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| ISSN: | 0167-2584 |
| DOI: | 10.1016/0167-2584(91)90004-B |