Model surface studies of metal oxides: Adsorption of water and methanol on ultrathin MgO films on Mo(100)

Journal Article · Sun Mar 01 00:00:00 EST 1992 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.461893· OSTI ID:7282443

Wu, M; Estrada, C A; Corneille, J S; Goodman, D W ^[1]

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1. Department of Chemistry, Texas A M University, College Station, Texas 77843-3255 (United States)

Model surface studies of magnesium oxide have been carried out using surface sensitive techniques. Ultrathin MgO films have been synthesized under ultrahigh vacuum (UHV) conditions by thermally evaporating Mg onto Mo(100) in the presence of oxygen. Low-energy electron diffraction (LEED) studies indicate that the MgO films grow epitaxially with the (100) face of MgO oriented parallel to Mo(100). The MgO films, prepared under optimum synthesis conditions, have essentially one-to-one stoichiometry, are nearly free from pointlike surface defects, and have properties essentially identical to those of bulk, single-crystal MgO. Adsorption of water and methanol onto the MgO films has been studied using high-resolution electron energy-loss spectroscopy (HREELS) and temperature programmed desorption (TPD). In order to circumvent the difficulty associated with intense multiple surface optical phonon (Fuchs--Kliewer modes) losses, a new approach to acquisition of HREELS data has been demonstrated. This new approach enables the direct observation of weak loss features due to excitation of the adsorbates without serious interference from multiple phonon losses. Our HREELS studies show that water and methanol undergo heterolytic dissociation, leading to the formation of hydroxyl and methoxy species, respectively.

• OSTI ID: 7282443
• Journal Information: Journal of Chemical Physics; (United States), Vol. 96:5; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
MAGNESIUM OXIDES
SURFACE PROPERTIES
SYNTHESIS
METHANOL
ADSORPTION
WATER
CATALYSIS
DESORPTION
DISSOCIATION
ELECTRON DIFFRACTION
ENERGY LOSSES
EPITAXY
HYDROXYL RADICALS
METHOXY RADICALS
MOLYBDENUM
MULTI-PHOTON PROCESSES
OPTIMIZATION
SPECTROSCOPY
STOICHIOMETRY
THIN FILMS
ALCOHOLS
ALKALINE EARTH METAL COMPOUNDS
ALKOXY RADICALS
CHALCOGENIDES
COHERENT SCATTERING
DIFFRACTION
ELEMENTS
FILMS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
LOSSES
MAGNESIUM COMPOUNDS
METALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RADICALS
SCATTERING
SORPTION
TRANSITION ELEMENTS
360602* - Other Materials- Structure & Phase Studies