Details
| Original language | English |
|---|---|
| Pages (from-to) | 4488-4501 |
| Number of pages | 14 |
| Journal | Journal of Physical Chemistry C |
| Volume | 119 |
| Issue number | 9 |
| Publication status | Published - 5 Mar 2015 |
Abstract
A combined experimental and computational study of the photocatalytic activity of titanium dioxide (TiO 2) for the degradation of nitrogen(II) oxide (NO) and acetaldehyde is reported. We employ five different TiO 2 photocatalysts including pure anatase and rutile samples. The experimental photonic efficiencies indicate that, under visible irradiation, the samples containing pure TiO 2 are active for the decomposition of NO but inactive for the acetaldehyde degradation. This is in accordance with our theoretical predictions, which reveal the presence of weak absorption bands in the visible region of the absorption spectra of the TiO 2-NO complexes. We demonstrate that these bands originate from charge-transfer excitations between the pollutant and the substrate. Although a ligand-to-metal charge-transfer process is expected to predominate, we find a competing mechanism in which one electron is promoted from the valence band of the semiconductor to the virtual π∗ states of NO. Both experimental and theoretical results show an enhanced vis-activity of anatase TiO 2 compared to rutile. We observe from the theoretical simulations the formation of reactive monocoordinated oxygen atoms at the anatase (001) surface for moderately low concentrations of the contaminant. Based on these findings, a new mechanism for the photo-oxidation of NO is proposed.
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Energy(all)
- General Energy
- Chemistry(all)
- Physical and Theoretical Chemistry
- Materials Science(all)
- Surfaces, Coatings and Films
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In: Journal of Physical Chemistry C, Vol. 119, No. 9, 05.03.2015, p. 4488-4501.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Nitrogen(II) oxide charge transfer complexes on TiO2
T2 - A new source for visible-light activity
AU - Freitag, J.
AU - Domínguez, A.
AU - Niehaus, T.A.
AU - Hülsewig, A.
AU - Dillert, R.
AU - Frauenheim, T.
AU - Bahnemann, D.W.
N1 - Publisher Copyright: © 2015 American Chemical Society. Copyright: Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2015/3/5
Y1 - 2015/3/5
N2 - A combined experimental and computational study of the photocatalytic activity of titanium dioxide (TiO 2) for the degradation of nitrogen(II) oxide (NO) and acetaldehyde is reported. We employ five different TiO 2 photocatalysts including pure anatase and rutile samples. The experimental photonic efficiencies indicate that, under visible irradiation, the samples containing pure TiO 2 are active for the decomposition of NO but inactive for the acetaldehyde degradation. This is in accordance with our theoretical predictions, which reveal the presence of weak absorption bands in the visible region of the absorption spectra of the TiO 2-NO complexes. We demonstrate that these bands originate from charge-transfer excitations between the pollutant and the substrate. Although a ligand-to-metal charge-transfer process is expected to predominate, we find a competing mechanism in which one electron is promoted from the valence band of the semiconductor to the virtual π∗ states of NO. Both experimental and theoretical results show an enhanced vis-activity of anatase TiO 2 compared to rutile. We observe from the theoretical simulations the formation of reactive monocoordinated oxygen atoms at the anatase (001) surface for moderately low concentrations of the contaminant. Based on these findings, a new mechanism for the photo-oxidation of NO is proposed.
AB - A combined experimental and computational study of the photocatalytic activity of titanium dioxide (TiO 2) for the degradation of nitrogen(II) oxide (NO) and acetaldehyde is reported. We employ five different TiO 2 photocatalysts including pure anatase and rutile samples. The experimental photonic efficiencies indicate that, under visible irradiation, the samples containing pure TiO 2 are active for the decomposition of NO but inactive for the acetaldehyde degradation. This is in accordance with our theoretical predictions, which reveal the presence of weak absorption bands in the visible region of the absorption spectra of the TiO 2-NO complexes. We demonstrate that these bands originate from charge-transfer excitations between the pollutant and the substrate. Although a ligand-to-metal charge-transfer process is expected to predominate, we find a competing mechanism in which one electron is promoted from the valence band of the semiconductor to the virtual π∗ states of NO. Both experimental and theoretical results show an enhanced vis-activity of anatase TiO 2 compared to rutile. We observe from the theoretical simulations the formation of reactive monocoordinated oxygen atoms at the anatase (001) surface for moderately low concentrations of the contaminant. Based on these findings, a new mechanism for the photo-oxidation of NO is proposed.
UR - http://www.scopus.com/inward/record.url?scp=84924107007&partnerID=8YFLogxK
U2 - 10.1021/jp5108069
DO - 10.1021/jp5108069
M3 - Article
VL - 119
SP - 4488
EP - 4501
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 9
ER -