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Surface composition of clean and oxidized Pd75Ag25(100) from photoelectron spectroscopy and density functional theory calculations

L. E. Walle ; Henrik Grönbeck (Institutionen för teknisk fysik, Kemisk fysik ; Kompetenscentrum katalys (KCK)) ; V. R. Fernandes ; S. Blomberg ; M. H. Farstad ; K. Schulte ; J. Gustafson ; J. N. Andersen ; E. Lundgren ; A. Borg
Surface Science (0039-6028). Vol. 606 (2012), 23-24, p. 1777-1782.
[Artikel, refereegranskad vetenskaplig]

High resolution photoelectron spectroscopy and density functional theory calculations have been used to study the composition of clean and oxidized Pd75Ag25( 100). The results for the clean surface confirm earlier reports of surface segregation by Wouda et al. (1998), where the top most layers are rich in Ag. The Pd 3d core level component from the surface region is observed at higher binding energies than the contribution from the bulk which is found to be a signature of Pd embedded in Ag. Low energy electron diffraction and scanning tunneling microscopy measurements reveal that oxidation of the Pd75Ag25(100) surface results in a (root 5 x root 5)R27 degrees-O structure similar to the one reported for Pd(100). The calculations suggest that the stable structure is a PdO(101) monolayer supported on a (100) surface rich in Ag at the interface to the stoichiometric alloy. The calculated core level shifts for the oxidized surface are in good agreement with the experimental observations.

Nyckelord: PdAg alloy, Surface oxide, Core level shifts, Pd75Ag25(100), Photoelectron spectroscopy, Density, pd-ag, electron-spectroscopy, palladium-silver, heat-treatment, mu-m, alloys, segregation, hydrogen, pd(111), oxidation



Denna post skapades 2012-11-08.
CPL Pubid: 165678

 

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Institutioner (Chalmers)

Institutionen för teknisk fysik, Kemisk fysik (1900-2015)
Kompetenscentrum katalys (KCK)

Ämnesområden

Kemi

Chalmers infrastruktur