In-situ characterization of adsorbed species on methanol synthesis catalysts by FT-IR spectroscopy
Transmission infrared spectroscopy was used to characterize adsorbed species on methanol synthesis catalysts during reaction conditions. A copper carbonyl, bidentate formate, and methoxy species were identified as stable surface groups. An adsorbed formaldehyde species was unstable at the reaction temperature, but could be observed on the catalyst surface at the beginning of the reaction. Surface species were very similar for feed mixtures of 1) carbon monoxide and hydrogen, 2) carbon monoxide, carbon dioxide, and hydrogen, and 3) formic acid and hydrogen. The role of copper in methanol synthesis catalysts was to increase the adsorption of carbon monoxide to form a linear carbonyl species. This carbonly promoted the hydrogenation of formate groups. The formate species was adsorbed on a zinc site (Zn/sub ..beta../) different from the zinc site (Zn/sub ..gamma../) on which formaldehyde and methoxy groups were adsorbed. The rate-determining step in methanol synthesis was determined to be the reaction of hydrogen from a hydroxyl species adsorbed on another zinc site (Zn/sub ..cap alpha../) with a methoxy group to yield methanol. It was established that at the experimental conditions used in this study, the methanol synthesis reaction was far from equilibrium while the water-gas shift reaction was near equilibrium.
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 5889453
- Country of Publication:
- United States
- Language:
- English
Similar Records
Infrared spectroscopy of Cu/ZnO catalysts for the water-gas shift reaction and methanol synthesis
Mechanism of selective methanol oxidation over vanadium oxide-titanium oxide catalysts: a FT-IT and flow reactor study
Related Subjects
10 SYNTHETIC FUELS
ALCOHOLS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CARBOXYLIC ACIDS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
COPPER
DISPERSIONS
ELEMENTS
FORMIC ACID
HYDROGEN
HYDROXY COMPOUNDS
INFRARED SPECTRA
METALS
METHANOL
MIXTURES
MONOCARBOXYLIC ACIDS
NONMETALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SORPTIVE PROPERTIES
SPECTRA
SURFACE PROPERTIES
SYNTHESIS
TRANSITION ELEMENTS
ZINC