Unexpected Behaviour of the Surface Composition of PtRh Alloys During Chemical Reaction
- BARALDI A.
- GIACOMELLO D.
- RUMIZ L.
- MORETUZZO M.
- LIZZIT S.
- BUATIER DE MONGEOT F.
- PAOLUCCI G.
- COMELLI G.
- ROSEI R.
- NIEUWENHUYS B.E.
- VALBUSA U.
- KISKINOVA M.P.
DOIAbstract
The changes in the surface composition of a Pt50Rh50(100) alloy due to an ongoing 2H2 + O2f2H2O chemical reaction have been studied in situ. Exploiting the high-energy resolution and surface sensitivity of synchrotron radiation core-level spectroscopy it was possible to monitor the population of the two transitions metals atoms at the gas-surface interface. Sequences of fast high-resolution core-level spectra of the Rh3d5/2, Pt4f7/2, and O1s core levels showed a continuous exchange of atoms between the first and subsurface layers. An unexpected Pt surface enrichement was found under slightly oxidizing conditions, opposite to what found in a highly oxidizing atmosphere
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