Electronic, structural, and reactive properties of ultrathin aluminum oxide films on Pt(111)

K Wilson, AF Lee, C Hardacre, RM Lambert*

*Corresponding author for this work

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30 Citations (Scopus)

Abstract

Low-energy electron diffraction, X-ray photoelectron spectroscopy, high-resolution electron energy-loss spectroscopy, scanning tunneling microscopy, and temperature-programmed reaction spectrometry results are reported for the structural and reactive behavior of alumina films grown on Pt(111) as a function of thickness and oxidation temperature. Submonolayer Al films undergo compete oxidation at 300 K, annealing at 1100 K resulting in formation of somewhat distorted crystalline gamma-alumina, Thicker deposits require 800 K oxidation to produce Al2O3, and these too undergo crystallization at 800 K, yielding islands of apparently undistorted gamma-alumina on the Pt(111) surface. Oxidation of a p(2 x 2) Pt3Al surface alloy occurs only at>800 K, resulting in Al extraction, These alumina films on Pt(lll) markedly increase the coverage of adsorbed SO4 resulting from SO2 chemisorption onto oxygen-precovered surfaces. This results in enhanced propane uptake and subsequent reactivity relative to SO4/Pt(111). A bifunctional mechanism is proposed to account for our observations, and the relevance of these to an understanding of the corresponding dispersed systems is discussed.

Original languageEnglish
Pages (from-to)1736-1744
Number of pages9
JournalJournal of Physical Chemistry B
Volume102
Issue number10
Publication statusPublished - 05 Mar 1998

Keywords

  • CATALYSTS
  • AL2O3 FILMS
  • AL(111)
  • GROWTH
  • ENERGY-LOSS-SPECTROSCOPY
  • PROPANE OXIDATION
  • INITIAL-STAGES
  • CORE-LEVEL PHOTOEMISSION
  • VIBRATIONAL PROPERTIES
  • THIN AL FILMS

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