Details
| Original language | English |
|---|---|
| Pages (from-to) | 245-252 |
| Number of pages | 8 |
| Journal | Surface science |
| Volume | 443 |
| Issue number | 3 |
| Early online date | 6 Dec 1999 |
| Publication status | Published - 20 Dec 1999 |
Abstract
Reaction fronts formed during the O2+H2 and NO+H2 reactions on a 70 angstroms thick microstructured Rh film on a Pt(100) substrate have been investigated using photoemission electron microscopy (PEEM) and scanning photoelectron microscopy (SPEM). The reactions were carried out in the 10-7 mbar range at T = 670 and 700 K. The photoelectron spectra revealed that the thin Rh film was alloyed with Pt due to vertical intermixing with the underlying Pt(100) substrate. The surface Rh/Pt ratio was found to vary from approximately 4 for an oxygen-free film to 4.8 in oxygen ambient. The O 1s spectra indicated the presence of oxide species along with chemisorbed oxygen on the alloyed film. The chemical maps revealed an enhanced tendency for oxide formation at the boundaries of the Rh/Pt film leading, under reducing conditions, to residual oxide and Rh enrichment expanding laterally to approximately 10 μm inside the film. This composition inhomogeneity can explain the peculiar ring patterns near Pt/Rh interfaces that were observed by PEEM under the reaction conditions.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Materials Science(all)
- Surfaces, Coatings and Films
- Materials Science(all)
- Materials Chemistry
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In: Surface science, Vol. 443, No. 3, 20.12.1999, p. 245-252.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Chemical waves and adsorbate-induced segregation on a Pt(100) surface microstructured with a thin Rh/Pt film
AU - Esch, F.
AU - Günther, S.
AU - Schütz, E.
AU - Schaak, A.
AU - Kevrekidis, I. G.
AU - Marsi, M.
AU - Kiskinova, M.
AU - Imbihl, R.
N1 - Funding Information: We thank Diego Lonza for his excellent technical assistance. We acknowledge Dr M. Gentili and his group from IESS for developing and providing the zone plate optics. This work was financially supported by the BMBF (FRG), the A. von Humboldt Foundation, EC grant under Contract No. EBRCH-GECT920013 and Sincrotrone Trieste SCpA.
PY - 1999/12/20
Y1 - 1999/12/20
N2 - Reaction fronts formed during the O2+H2 and NO+H2 reactions on a 70 angstroms thick microstructured Rh film on a Pt(100) substrate have been investigated using photoemission electron microscopy (PEEM) and scanning photoelectron microscopy (SPEM). The reactions were carried out in the 10-7 mbar range at T = 670 and 700 K. The photoelectron spectra revealed that the thin Rh film was alloyed with Pt due to vertical intermixing with the underlying Pt(100) substrate. The surface Rh/Pt ratio was found to vary from approximately 4 for an oxygen-free film to 4.8 in oxygen ambient. The O 1s spectra indicated the presence of oxide species along with chemisorbed oxygen on the alloyed film. The chemical maps revealed an enhanced tendency for oxide formation at the boundaries of the Rh/Pt film leading, under reducing conditions, to residual oxide and Rh enrichment expanding laterally to approximately 10 μm inside the film. This composition inhomogeneity can explain the peculiar ring patterns near Pt/Rh interfaces that were observed by PEEM under the reaction conditions.
AB - Reaction fronts formed during the O2+H2 and NO+H2 reactions on a 70 angstroms thick microstructured Rh film on a Pt(100) substrate have been investigated using photoemission electron microscopy (PEEM) and scanning photoelectron microscopy (SPEM). The reactions were carried out in the 10-7 mbar range at T = 670 and 700 K. The photoelectron spectra revealed that the thin Rh film was alloyed with Pt due to vertical intermixing with the underlying Pt(100) substrate. The surface Rh/Pt ratio was found to vary from approximately 4 for an oxygen-free film to 4.8 in oxygen ambient. The O 1s spectra indicated the presence of oxide species along with chemisorbed oxygen on the alloyed film. The chemical maps revealed an enhanced tendency for oxide formation at the boundaries of the Rh/Pt film leading, under reducing conditions, to residual oxide and Rh enrichment expanding laterally to approximately 10 μm inside the film. This composition inhomogeneity can explain the peculiar ring patterns near Pt/Rh interfaces that were observed by PEEM under the reaction conditions.
UR - http://www.scopus.com/inward/record.url?scp=0343462220&partnerID=8YFLogxK
U2 - 10.1016/S0039-6028(99)01015-8
DO - 10.1016/S0039-6028(99)01015-8
M3 - Article
AN - SCOPUS:0343462220
VL - 443
SP - 245
EP - 252
JO - Surface science
JF - Surface science
SN - 0039-6028
IS - 3
ER -