Details
| Original language | English |
|---|---|
| Pages (from-to) | 129-136 |
| Number of pages | 8 |
| Journal | Journal of catalysis |
| Volume | 261 |
| Issue number | 2 |
| Early online date | 12 Nov 2008 |
| Publication status | Published - 25 Jan 2009 |
Abstract
Ammonia oxidation over different Pt single crystal orientations and a Pt foil has been studied in the 10-5 to 10-2 mbar range with rate measurements and LEED. The reaction exhibits only a moderate structure sensitivity with the activity varying in the sequence Pt foil:Pt(533):Pt(865):Pt(443):Pt(100) = 6:4:4:2:1. The activity is apparently mainly determined by the oxygen sticking coefficient which reaches 0.14 on the Pt foil. Broad hystereses in the reaction rates upon cyclic variation of the temperature are associated with reversible structural changes. The extent of reaction-induced structural changes depends strongly on the orientation, the total pressure and also on the ratio of the reactants NH3/O2. On Pt(533) and Pt(443) the extent of restructuring and the hysteretic behavior was found to depend in a non-monotonic way on the total pressure. Exposure to reaction conditions at 10-3 mbar creates a disordered surface as seen in LEED with no LEED spots visible; but after exposure to reaction conditions at 10-2 mbar the integral order beams in LEED are again visible.
Keywords
- Ammonia oxidation, Kinetics, Platinum, Stepped platinum surface
ASJC Scopus subject areas
- Chemical Engineering(all)
- Catalysis
- Chemistry(all)
- Physical and Theoretical Chemistry
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In: Journal of catalysis, Vol. 261, No. 2, 25.01.2009, p. 129-136.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Structure sensitivity of ammonia oxidation over platinum
AU - Zeng, Ying Feng
AU - Imbihl, Ronald
N1 - Funding Information: Assistance from Dr. Sebastian Günter in the experiments is gratefully acknowledged. The authors are indebted to the group of M. Baerns for supplying a Pt foil as sample. This work was supported by the DFG under the priority program 1091 ‘Bridging the gap between ideal and real systems in heterogeneous catalysis’.
PY - 2009/1/25
Y1 - 2009/1/25
N2 - Ammonia oxidation over different Pt single crystal orientations and a Pt foil has been studied in the 10-5 to 10-2 mbar range with rate measurements and LEED. The reaction exhibits only a moderate structure sensitivity with the activity varying in the sequence Pt foil:Pt(533):Pt(865):Pt(443):Pt(100) = 6:4:4:2:1. The activity is apparently mainly determined by the oxygen sticking coefficient which reaches 0.14 on the Pt foil. Broad hystereses in the reaction rates upon cyclic variation of the temperature are associated with reversible structural changes. The extent of reaction-induced structural changes depends strongly on the orientation, the total pressure and also on the ratio of the reactants NH3/O2. On Pt(533) and Pt(443) the extent of restructuring and the hysteretic behavior was found to depend in a non-monotonic way on the total pressure. Exposure to reaction conditions at 10-3 mbar creates a disordered surface as seen in LEED with no LEED spots visible; but after exposure to reaction conditions at 10-2 mbar the integral order beams in LEED are again visible.
AB - Ammonia oxidation over different Pt single crystal orientations and a Pt foil has been studied in the 10-5 to 10-2 mbar range with rate measurements and LEED. The reaction exhibits only a moderate structure sensitivity with the activity varying in the sequence Pt foil:Pt(533):Pt(865):Pt(443):Pt(100) = 6:4:4:2:1. The activity is apparently mainly determined by the oxygen sticking coefficient which reaches 0.14 on the Pt foil. Broad hystereses in the reaction rates upon cyclic variation of the temperature are associated with reversible structural changes. The extent of reaction-induced structural changes depends strongly on the orientation, the total pressure and also on the ratio of the reactants NH3/O2. On Pt(533) and Pt(443) the extent of restructuring and the hysteretic behavior was found to depend in a non-monotonic way on the total pressure. Exposure to reaction conditions at 10-3 mbar creates a disordered surface as seen in LEED with no LEED spots visible; but after exposure to reaction conditions at 10-2 mbar the integral order beams in LEED are again visible.
KW - Ammonia oxidation
KW - Kinetics
KW - Platinum
KW - Stepped platinum surface
UR - http://www.scopus.com/inward/record.url?scp=58649104416&partnerID=8YFLogxK
U2 - 10.1016/j.jcat.2008.05.032
DO - 10.1016/j.jcat.2008.05.032
M3 - Article
AN - SCOPUS:58649104416
VL - 261
SP - 129
EP - 136
JO - Journal of catalysis
JF - Journal of catalysis
SN - 0021-9517
IS - 2
ER -