Chemisorption and decomposition of pyrrole on Pd{111}

CJ Baddeley, C Hardacre, RM Ormerod, RM Lambert

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26 Citations (Scopus)

Abstract

XPS, TPD and HREEL results indicate that molecular pyrrole is a fragile adsorbate on clean Pd{111}. At 200 K and for low coverages, the molecule remains intact and adopts an almost flat-lying geometry. With increasing coverage, pyrrole molecules tilt away from the surface and undergo N-H bond cleavage to form strongly tilted pyrrolyl (C4H4N) species. In addition, a weakly bound, strongly tilted form of molecular pyrrole is observed at coverages approaching saturation. Heating pyrrole monolayers results in desorption of similar to 15% of the overlayer as molecular pyrrole and N-a+ C4H4Na recombination with formation of hat-lying pyrrole molecules. This strongly bound species undergoes decomposition to adsorbed CN, CHx and H, leading ultimately to desorption of HCN and H-2. The implications of these results for the production of pyrrole by a heterogeneously catalysed route are discussed.

Original languageEnglish
Pages (from-to)1-8
Number of pages8
JournalSurface Science
Volume369
Issue number1-3
Publication statusPublished - 20 Dec 1996

Keywords

  • palladium
  • thermal desorption spectroscopy
  • PALLADIUM
  • ACETYLENE
  • X-ray photoelectron spectroscopy
  • FURAN
  • molecule-solid reactions
  • chemisorption
  • THIOPHENE
  • vibrations of adsorbed molecules
  • SURFACE
  • catalysis
  • low index single crystal surfaces
  • electron energy loss spectroscopy
  • pyrrole
  • BENZENE
  • ADSORPTION
  • VIBRATIONAL CHARACTERIZATION

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