In situ XPS study of Pd(111) oxidation at elevated pressure, Part 2: Palladium oxidation in the 10^1 mbar range

Harald Gabasch, Institut für Physikalische Chemie, Universität Innsbruck
Werner Unterberger, Institut für Physikalische Chemie, Universität Innsbruck
Konrad Hayek, Institut für Physikalische Chemie, Universität Innsbruck
Bernhard Klötzer, Institut für Physikalische Chemie, Universität Innsbruck
Evgueni Kleimenov, Abteilung Anorganische Chemie, Fritzx-Haber-Institut der Max-Planck-Gesellschaft
Detre Teschner, Abteilung Anorganische Chemie, Fritz-Haber-Institut der Max-Lanck-Gesellschaft
Spiros Zafeiratos, Abteilung Anorganische Chemie, Fritz-Haber-Institut der Max-Planck-Gesellschaft
Michael Hävecker, Abteilung Anorganische Chemie, Fritz-Haber-Institut der Max-Olanck-Gesellschaft
Axel Knop-Gericke, Abteilung Anorganische Chemie, Fritz-Haber-Institut der Max-Olanck-Gesellschaft
Robert Schlögl, Abteilung Anorganische Chemie, Fritz-Haber-Institut der Max-Olanck-Gesellschaft
Jinyi Han, School of Chemical Engineering, Purdue University
Fabio H. Ribeiro, School of Chemical Engineering, Purdue University
Balazs Aszalos-Kiss, Materials and Surface Science Institute and Physics Department, University of Limerick
Teresa Curtin, Materials and Surface Science Institute and Physics Department, University of Limerick
Dmitry Zemlyanov, Birck Nanotechnology Center, Purdue University; Materials and Surface Science Institute, and Physics Department, University of Limerick

Date of this Version

May 2006

Citation

Surface Science 600 (2006) 2980–2989

This document has been peer-reviewed.

 

Comments

doi:10.1016/j.susc.2006.05.029

Abstract

The oxidation of the Pd(1 1 1) surface was studied by in situ XPS during heating and cooling in 0.4 mbar O2. The in situ XPS data were complemented by ex situ TPD results. A number of oxygen species and oxidation states of palladium were observed in situ and ex situ. At 430 K, the Pd(1 1 1) surface was covered by a 2D oxide and by a supersaturated Oads layer. The supersaturated Oads layer transforms into the Pd5O4 phase upon heating and disappears completely at approximately 470 K. Simultaneously, small clusters of PdO, PdO seeds, are formed. Above 655 K, the bulk PdO phase appears and this phase decomposes completely at 815 K. Decomposition of the bulk oxide is followed by oxygen dissolution in the near-surface region and in the bulk. The oxygen species dissolved in the bulk is more favoured at high temperatures because oxygen cannot accumulate in the near-surface region and di

 

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