Eur. Phys. J. D 45, 485-489 (2007)
https://doi.org/10.1140/epjd/e2007-00178-5

Predicting experimental signatures for the oxidation of magnesia supported palladium clusters by density functional theory

¹ Fraunhofer Institut für Werkstoffmechanik, Wöhlerstraße 11, 79108 Freiburg, Germany
² Freiburg Materials Research Center, Stefan-Meier-Straße 21, 79104 Freiburg, Germany

Corresponding authors: ^a bernd.huber@fmf.uni-freiburg.de - ^b michael.moseler@iwm.fraunhofer.de

Received: 31 January 2007
Revised: 8 May 2007
Published online: 1 June 2007

Abstract

We showed in a recent density functional study that small palladium cluster on a MgO surface with F-centers can be oxidized to epitaxial Pd_xO_y nano-oxides below room temperature [1]. Here, we employ density functional theory in order to explore different methods for an experimental verification of the Pd_xO_y formation. The electronic density of states (DOS) of bare, O₂-decorated and of oxidized palladium cluster was calculated. For many cluster sizes a clear difference in the DOS could be observed allowing for a detection of the oxidation with surface sensitive spectroscopic methods. In addition, adsorption sites and stretch frequencies of a single CO molecule on bare and oxidized Pd₄ clusters were calculated. While CO prefers hollow sites on Pd₄, top adsorption sites are found for Pd₄O₂. Markedly different CO stretch frequencies indicate a possible discrimination of bare clusters and oxides by Fourier transform infrared spectroscopy.