Electronic, structural, and reactive properties of ultrathin aluminum oxide films on Pt(111)
Data(s) |
05/03/1998
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Resumo |
<p>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.</p> |
Identificador | |
Idioma(s) |
eng |
Direitos |
info:eu-repo/semantics/restrictedAccess |
Fonte |
Wilson , K , Lee , A F , Hardacre , C & Lambert , R M 1998 , ' Electronic, structural, and reactive properties of ultrathin aluminum oxide films on Pt(111) ' Journal of Physical Chemistry B , vol 102 , no. 10 , pp. 1736-1744 . |
Palavras-Chave | #CATALYSTS #AL2O3 FILMS #AL(111) #GROWTH #ENERGY-LOSS-SPECTROSCOPY #PROPANE OXIDATION #INITIAL-STAGES #CORE-LEVEL PHOTOEMISSION #VIBRATIONAL PROPERTIES #THIN AL FILMS |
Tipo |
article |