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;COMELLI, GIOVANNI;ROSEI, RENZO;
2005

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.
http://pubs.acs.org/doi/abs/10.1021/ja044372%2B?prevSearch=%255BContrib%253A%2Bbaraldi%255D&searchHistoryKey=
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11368/1691699
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