CO adsorption on Cu3Pt(111) and CuPt3(111):: a comparative HREELS study

The adsorption of CO on the Cu3Pt(111) and the CuPt3(111) surface at 100 K has been studied using high resolution electron energy loss spectroscopy. Both surfaces show CO adsorption on on-top platinum and copper sites. The relative amount of copper sites populated is - as can be expected - higher on the Cu3Pt(111) surface. Additionally, bridge sites are populated on both surfaces. Due to the different stoichiometries of the substrates the population of these sites shows significant differences. The loss energies for CO on CuPt3(111) show little difference compared to CO on Pt(111). However, in contrast to Pt(111) all sites are populated concurrently on CuPt3(111). For CO on Cu3Pt(111) a large red-shift of the on-top C-O vibrational loss has been found for platinum sites accompanied by a significant weakening of the Pt-CO bond compared to CO on Pt(111). (C) 1999 Elsevier Science B.V. All rights reserved.