Details
| Original language | English |
|---|---|
| Pages (from-to) | 709-711 |
| Number of pages | 3 |
| Journal | Journal of Physical Chemistry |
| Volume | 88 |
| Issue number | 4 |
| Publication status | Published - 1984 |
| Externally published | Yes |
Abstract
When a TiO2 sol containing an adsorbed electron scavenger such as platinum or methyl viologen is flashed with a 347-nm laser, an immediate broad absorption with λmax = 475 nm is observed. In acid solution the absorption decays within milliseconds. In alkaline solution it decays within microseconds, depending on the OH- concentration, and OH- ions are consumed in the process. In the presence of scavengers for positive holes the decay is faster, while oxygen does not have any effect. This absorption spectrum is attributed to excess positive holes trapped at the surface of the colloidal particles. When a TiO2 sol containing an adsorbed scavenger for positive holes, such as polyvinyl alcohol or thiocyanate, is flashed, a broad absorption with λmax = 650 nm is observed. It decays in the presence of electron scavengers. This spectrum is attributed to excess electrons trapped close to the surface of the colloidal particles.
ASJC Scopus subject areas
- Engineering(all)
- General Engineering
- Chemistry(all)
- Physical and Theoretical Chemistry
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In: Journal of Physical Chemistry, Vol. 88, No. 4, 1984, p. 709-711.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Flash photolysis observation of the absorption spectra of trapped positive holes and electrons in colloidal TiO2
AU - Bahnemann, D.
AU - Henglein, A.
AU - Lilie, J.
AU - Spanhel, L.
N1 - Copyright: Copyright 2020 Elsevier B.V., All rights reserved.
PY - 1984
Y1 - 1984
N2 - When a TiO2 sol containing an adsorbed electron scavenger such as platinum or methyl viologen is flashed with a 347-nm laser, an immediate broad absorption with λmax = 475 nm is observed. In acid solution the absorption decays within milliseconds. In alkaline solution it decays within microseconds, depending on the OH- concentration, and OH- ions are consumed in the process. In the presence of scavengers for positive holes the decay is faster, while oxygen does not have any effect. This absorption spectrum is attributed to excess positive holes trapped at the surface of the colloidal particles. When a TiO2 sol containing an adsorbed scavenger for positive holes, such as polyvinyl alcohol or thiocyanate, is flashed, a broad absorption with λmax = 650 nm is observed. It decays in the presence of electron scavengers. This spectrum is attributed to excess electrons trapped close to the surface of the colloidal particles.
AB - When a TiO2 sol containing an adsorbed electron scavenger such as platinum or methyl viologen is flashed with a 347-nm laser, an immediate broad absorption with λmax = 475 nm is observed. In acid solution the absorption decays within milliseconds. In alkaline solution it decays within microseconds, depending on the OH- concentration, and OH- ions are consumed in the process. In the presence of scavengers for positive holes the decay is faster, while oxygen does not have any effect. This absorption spectrum is attributed to excess positive holes trapped at the surface of the colloidal particles. When a TiO2 sol containing an adsorbed scavenger for positive holes, such as polyvinyl alcohol or thiocyanate, is flashed, a broad absorption with λmax = 650 nm is observed. It decays in the presence of electron scavengers. This spectrum is attributed to excess electrons trapped close to the surface of the colloidal particles.
UR - http://www.scopus.com/inward/record.url?scp=33845470493&partnerID=8YFLogxK
U2 - 10.1021/j150648a018
DO - 10.1021/j150648a018
M3 - Article
AN - SCOPUS:33845470493
VL - 88
SP - 709
EP - 711
JO - Journal of Physical Chemistry
JF - Journal of Physical Chemistry
SN - 0022-3654
IS - 4
ER -