Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 3522-3540 |
| Seitenumfang | 19 |
| Fachzeitschrift | Physical Chemistry Chemical Physics |
| Jahrgang | 9 |
| Ausgabenummer | 27 |
| Publikationsstatus | Veröffentlicht - 3 Mai 2007 |
Abstract
Catalytic ammonia oxidation over platinum has been studied experimentally from UHV up to atmospheric pressure with polycrystalline Pt and with the Pt single crystal orientations (533), (443), (865), and (100). Density functional theory (DFT) calculations explored the reaction pathways on Pt(111) and Pt(211). It was shown, both in theory and experimentally, that ammonia is activated by adsorbed oxygen, i.e. by Oad or by OHad. In situ XPS up to 1 mbar showed the existence of NHx (x = 0,1,2,3) intermediates on Pt(533). Based on a mechanism of ammonia activation via the interaction with Oad/OHad a detailed and a simplified mathematical model were formulated which reproduced the experimental data semiquantitatively. From transient experiments in vacuum performed in a transient analysis of products (TAP) reactor it was concluded that N2O is formed by recombination of two NOad species and by a reaction between NOad and NHx,ad (x = 0,1,2) fragments. Reaction-induced morphological changes were studied with polycrystalline Pt in the mbar range and with stepped Pt single crystals as model systems in the range 10-5-10-1 mbar.
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in: Physical Chemistry Chemical Physics, Jahrgang 9, Nr. 27, 03.05.2007, S. 3522-3540.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Catalytic ammonia oxidation on platinum
T2 - Mechanism and catalyst restructuring at high and low pressure
AU - Imbihl, R.
AU - Scheibe, A.
AU - Zeng, Y. F.
AU - Günther, S.
AU - Kraehnert, R.
AU - Kondratenko, V. A.
AU - Baerns, M.
AU - Offermans, W. K.
AU - Jansen, A. P.J.
AU - Van Santen, R. A.
PY - 2007/5/3
Y1 - 2007/5/3
N2 - Catalytic ammonia oxidation over platinum has been studied experimentally from UHV up to atmospheric pressure with polycrystalline Pt and with the Pt single crystal orientations (533), (443), (865), and (100). Density functional theory (DFT) calculations explored the reaction pathways on Pt(111) and Pt(211). It was shown, both in theory and experimentally, that ammonia is activated by adsorbed oxygen, i.e. by Oad or by OHad. In situ XPS up to 1 mbar showed the existence of NHx (x = 0,1,2,3) intermediates on Pt(533). Based on a mechanism of ammonia activation via the interaction with Oad/OHad a detailed and a simplified mathematical model were formulated which reproduced the experimental data semiquantitatively. From transient experiments in vacuum performed in a transient analysis of products (TAP) reactor it was concluded that N2O is formed by recombination of two NOad species and by a reaction between NOad and NHx,ad (x = 0,1,2) fragments. Reaction-induced morphological changes were studied with polycrystalline Pt in the mbar range and with stepped Pt single crystals as model systems in the range 10-5-10-1 mbar.
AB - Catalytic ammonia oxidation over platinum has been studied experimentally from UHV up to atmospheric pressure with polycrystalline Pt and with the Pt single crystal orientations (533), (443), (865), and (100). Density functional theory (DFT) calculations explored the reaction pathways on Pt(111) and Pt(211). It was shown, both in theory and experimentally, that ammonia is activated by adsorbed oxygen, i.e. by Oad or by OHad. In situ XPS up to 1 mbar showed the existence of NHx (x = 0,1,2,3) intermediates on Pt(533). Based on a mechanism of ammonia activation via the interaction with Oad/OHad a detailed and a simplified mathematical model were formulated which reproduced the experimental data semiquantitatively. From transient experiments in vacuum performed in a transient analysis of products (TAP) reactor it was concluded that N2O is formed by recombination of two NOad species and by a reaction between NOad and NHx,ad (x = 0,1,2) fragments. Reaction-induced morphological changes were studied with polycrystalline Pt in the mbar range and with stepped Pt single crystals as model systems in the range 10-5-10-1 mbar.
UR - http://www.scopus.com/inward/record.url?scp=34447252580&partnerID=8YFLogxK
U2 - 10.1039/b700866j
DO - 10.1039/b700866j
M3 - Article
AN - SCOPUS:34447252580
VL - 9
SP - 3522
EP - 3540
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
SN - 1463-9076
IS - 27
ER -