Oscillations of surface composition in Pt-Co alloys induced by CO chemisorption

The influence of carbon monoxide adsorption on surface composition of cobalt alloys, containing 30 and 1 at.% platinum was studied by low energy ion scattering spectroscopy and X-ray photoelectron spectroscopy. Composition oscillations in Co/Pt ratio across the several outermost layers and caused by CO chemisorbed at 400 K were found. XPS indicated the presence of both molecular and dissociatively adsorbed CO. A possible explanation of the surface process which cause these oscillations is proposed. © 1992 J.C. Baltzer A.G. Scientific Publishing Company.