Surface composition of clean and oxidized Pd75Ag25(100) from photoelectron spectroscopy and density functional theory calculations
Artikel i vetenskaplig tidskrift, 2012

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.

pd-ag

mu-m

Pd75Ag25(100)

segregation

PdAg alloy

Surface oxide

Density

hydrogen

oxidation

pd(111)

heat-treatment

Core level shifts

Photoelectron spectroscopy

alloys

palladium-silver

electron-spectroscopy

Författare

L. E. Walle

Norges teknisk-naturvitenskapelige universitet

Henrik Grönbeck

Chalmers, Teknisk fysik, Kemisk fysik

Kompetenscentrum katalys (KCK)

V. R. Fernandes

Norges teknisk-naturvitenskapelige universitet

S. Blomberg

Lunds universitet

M. H. Farstad

Norges teknisk-naturvitenskapelige universitet

K. Schulte

Lunds universitet

J. Gustafson

Lunds universitet

J. N. Andersen

Lunds universitet

E. Lundgren

Lunds universitet

A. Borg

Norges teknisk-naturvitenskapelige universitet

Surface Science

0039-6028 (ISSN)

Vol. 606 23-24 1777-1782

Ämneskategorier

Kemi

DOI

10.1016/j.susc.2012.07.006