Evidence for slow oxygen exchange between multiple adsorption sites at high oxygen coverages on Pt(111)

Dmitri I. Jerdev, Jooho Kim, Matthias Batzill, Bruce E. Koel

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

Thermal desorption (TPD) measurements using isotopically labeled oxygen were carried out on a Pt(111) surface for oxygen coverages Θ(O) between 0.25-0.7 monolayers (ML, 1 ML corresponds to 1.505×1015cm-2). In these experiments, 18O2 was used to produce Θ(O)=0.25 ML and then N16O2 was used to obtain larger values of Θ(O) at the surface. We observed differences in the peak shapes and temperatures maxima of the O2 TPD peaks from the different combinations of labeled O2 molecules (16O2, 16O18O, and 18O2), and this provides direct evidence for multiple adsorption sites and slow oxygen exchange between these sites during dosing or heating in TPD. Also, we have reinvestigated the high resolution electron energy loss spectroscopy (HREELS) spectra of these surfaces. We find that there is only a 22 cm-1 shift of the loss peak due to Pt-O stretching vibrations for Θ(O) between 0.25-0.55 ML, consistent with similar Pt-O bond energies at the different sites occupied by oxygen adatoms at these coverages on the Pt(111) surface.

Original languageEnglish (US)
Pages (from-to)L91-L96
JournalSurface Science
Volume498
Issue number1-2
DOIs
StatePublished - Feb 1 2002
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

Keywords

  • Chemisorption
  • Electron energy loss spectroscopy (EELS)
  • Nitrogen oxides
  • Oxygen
  • Platinum
  • Thermal desorption

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