Monitoring surfaces on the molecular level during catalytic reactions at high pressure by sum frequency generation vibrational spectroscopy and scanning tunneling microscopy

Paul S. Cremer, B. J. McIntyre, M. Salmeron, Y. R. Shen, G. A. Somorjai

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

Sum frequency generation (SFG), using non-linear laser optics, detects vibrational spectra of submonolayer amounts of adsorbates with excellent energy and time resolution. Scanning tunneling spectroscopy (STM) is sensitive to the atomic surface structure; readily imaging defects, steps and kinks as well as stationary adsorbed species. Both of these techniques can be used during reactions at high pressures and temperatures to obtain molecular information in situ. We report studies of propylene hydrogenation over Pt(111) crystal surfaces at atmospheric pressures and 300 K using SFG and STM. Four surface species (2-propyl, π-bonded propylene, di σ-bonded propylene, and propylidyne) were identified; the first two being implicated as reaction intermediates. The platinum surface structure remains unchanged during the reaction, consistent with the structure insensitive nature of olefin hydrogénation. Propylene decomposition induced substantial surface reconstruction.

Original languageEnglish (US)
Pages (from-to)11-18
Number of pages8
JournalCatalysis Letters
Volume34
Issue number1-2
DOIs
StatePublished - Mar 1 1995

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)

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