title: Desorption of oxygen from alloyed Ag/Pt(111).
abstract: We have investigated the interaction of oxygen with the Ag/Pt(111) surface alloy by thermal desorption spectroscopy (TDS). The surface alloy was formed during the deposition of sub-monolayer amounts of silver on Pt(111) at 800 K and subsequent cooling to 300 K. The low-temperature phase of the surface alloy is composed of nanometer-sized silver rich stripes, embedded within platinum-rich domains, which were characterized with spot profile analysis low energy electron diffraction. The TDS measurements show that oxygen adsorption is blocked on Ag sites: the saturation coverage of oxygen decreases with increasing Ag coverage. Also, the activation energy for desorption (Edes) decreases with Ag coverage. The analysis of the desorption spectra from clean Pt(111) shows a linear decay of Edes with oxygen coverage, which indicates repulsive interactions between the adsorbed oxygen atoms. In contrast, adsorption on alloyed Ag/Pt(111) leads to an attractive interaction between adsorbed oxygen atoms.
authors: Physics of Interfaces and Nanomaterials, MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors: Maciej
authors: M
authors: Jankowski
authors: Physics of Interfaces and Nanomaterials, MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors: Herbert
authors: H
authors: Wormeester
authors: Physics of Interfaces and Nanomaterials, MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors: Harold J W
authors: HJ
authors: Zandvliet
authors: Physics of Interfaces and Nanomaterials, MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors: Bene
authors: B
authors: Poelsema