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.
Unexpected Behaviour of the Surface Composition of PtRh Alloys During Chemical Reaction / Baraldi, Alessandro; Giacomello, D.; Rumiz, L.; Moretuzzo, M.; Lizzit, S.; BUATIER DE MONGEOT, F.; Paolucci, G.; Comelli, Giovanni; Rosei, Renzo; Nieuwenhuys, B. E.; Valbusa, U.; Kiskinova, M. P.. - In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. - ISSN 0002-7863. - STAMPA. - 127:(2005), pp. 5671-5674. [10.1021/ja044372+]
Unexpected Behaviour of the Surface Composition of PtRh Alloys During Chemical Reaction
BARALDI, Alessandro;COMELLI, GIOVANNI;ROSEI, RENZO;
2005-01-01
Abstract
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.Pubblicazioni consigliate
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