Chemically resolved dynamical imaging of catalytic reactions on composite surfaces

F. Esch, S. Günther, E. Schütz, A. Schaak, I. G. Kevrekidis, M. Marsi, M. Kiskinova, R. Imbihl

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19 Scopus citations

Abstract

The catalytic reduction of NO by hydrogen is investigated at T = 650 K and p ≈ 10-6 CT mbar on a microstructured Rh/Pt(100) surface consisting of Pt(100) domains surrounded by a 600 Å thick Rh film. Synchrotron radiation scanning photoemission microcopy (SPEM), using photons focused into a spot of less then 0.2 μm diameter, is employed as a spatially and chemically resolving in situ technique. The chemical wave, which arise in the bistable system NO + H2/Rh are imaged with SPEM monitoring the N 1s and O 1s photoelectrons. The reaction fronts initiate transitions from an inactive oxygen-covered surface (ΘO ≈ 0.25 ML) to a reactive nitroeen-covered surface (ΘN ≈ 0.06 ML) At the Pt/Rh interface, synergetic effects can be observed: the chemical waves on the Rh film nucleate preferentially at the Pt/Rh interface. This nucleation is poisoned by carbon contamination on the Pt area but is prevented in the vicinity of the Pt/Rh interface by the adjacent clean Rh film. No segregation of Pt to the surface was observed for the 600 Å thick Rh film.

Original languageEnglish (US)
Pages (from-to)85-90
Number of pages6
JournalCatalysis Letters
Volume52
Issue number1
StatePublished - Jan 1 1998

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)

Keywords

  • Chemical waves
  • Dynamical imaging
  • Microstructured composite surfaces
  • NO reduction
  • PEEM
  • Photoemission electron microscopy
  • Pt
  • Rh
  • SPEM
  • Scanning photoemission microscopy

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    Esch, F., Günther, S., Schütz, E., Schaak, A., Kevrekidis, I. G., Marsi, M., Kiskinova, M., & Imbihl, R. (1998). Chemically resolved dynamical imaging of catalytic reactions on composite surfaces. Catalysis Letters, 52(1), 85-90.