Methanol adsorption and decomposition on rhodium

Journal Article · Sun Oct 01 00:00:00 EDT 1989 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(89)90164-4· OSTI ID:6844623

Chuah, G K; Kruse, N; Schmidt, W A; Block, J H; Abend, G ^[1]

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1. Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin (Germany, F.R.)

The decomposition of methanol on rhodium probed from {approximately}200 atomic sites of the (001) or (111) planes or Rh field emitter crystals but randomly with regard to crystallographic zones was studied by pulsed field desorption mass spectrometry. High electric field pulses were used to quantitatively desorb the final products, carbon monoxide and hydrogen, thus achieving steady-state conditions. Substantial amounts of methoxy (mainly desorbed as CH{sub 3}{sup +} ions) were also present at the surface. Applying a steady electric field, F{sub R} {ge} 4 V/nm, between the field pulses, led to a deceleration of the decomposition reaction and to increase of the amount of adsorbed CH{sub 3}O and CH{sub 2}O species. There were indicators that the rate-determining step of the reaction is C-H bond cleavage in adsorbed methoxy to form the CH{sub 2}O intermediate. This was supported by the observation of a kinetic isotope effect in the formation of CD{sub 2}O and CHDO from methyl-d{sub 2}-alcohol, CHD{sub 2}OH. Here, the C-H bond breaking to form the CD{sub 2}O was found to be twice as fast as the breaking of the C-D bond which results in CHDO. Field ion microscopy was applied to investigate the influence of the reaction on the structure of the whole hemispherical single crystal surface. There were neither topographic changes nor corrosion of the Rh surface after field-free exposure to 2 Pa methanol at temperatures up to 423 K.

• OSTI ID: 6844623
• Journal Information: Journal of Catalysis; (USA), Vol. 119:2; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
10 SYNTHETIC FUELS
METHANOL
ADSORPTION
DECOMPOSITION
RHODIUM
CATALYTIC EFFECTS
CARBON MONOXIDE
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CLEAVAGE
CRYSTAL STRUCTURE
DESORPTION
DEUTERIUM
ELECTRIC FIELDS
HYDROGEN
ION MICROSCOPY
MASS SPECTROSCOPY
PULSE TECHNIQUES
SORPTIVE PROPERTIES
SURFACE PROPERTIES
SYNTHESIS
SYNTHESIS GAS
ALCOHOLS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
FLUIDS
GASES
HYDROGEN ISOTOPES
HYDROXY COMPOUNDS
ISOTOPES
KINETICS
LIGHT NUCLEI
METALS
MICROSCOPY
MICROSTRUCTURE
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
REACTION KINETICS
SORPTION
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STABLE ISOTOPES
TRANSITION ELEMENTS
010408* - Coal
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