Formation of a carbonaceous adsorbate layer on the surface of Pt-Cu alloys

Abstract

Selective chemisorption of ethene and the chemisorption induced surface segregation of Pt upon the chemisorption of ethene (and its subsequent decomposition) on Pt-Cu alloys have been studied by Auger electron spectroscopy. The experimental results have also been evaluated by computer simulations of the various possible processes upon the chemisorption. In these computer simulations a modified Gallon model has been used in order to describe the variations in the intensities of the Pt and the Cu surface sensitive Auger transitions. Our present results indicate a preferential chemisorption of the carbonaceous species onto Pt sites, and a chemisorption induced surface segregation of Pt. Alloying of Pt with Cu results in a decreased coking of the catalyst.