Study of surface species present during CO hydrogenation
An investigation was conducted to determine the nature and reactivity of the carbon species present on the catalyst surface during CO hydrogenation over supported Ru catalysts. This study has involved the use of isotopic transient response techniques, Fourier-transform infrared spectroscopy, temperature-programmed desorption (TPD) and {sup 13}C NMR spectroscopy. Infrared spectroscopy has shown that carbon monoxide adsorbs as a linear and tricarbonyl species on Ru/SiO{sub 2}. The tricarbonyl species are believed to be adsorbed on isolated Ru atoms or clusters or on partially oxidized sites on Ru particles. TPD spectra have shown that the tricarbonyl species is more weakly bonded to the surface than the linearly adsorbed CO. Only linearly adsorbed CO is involved in the formation of methane. The existence of linearly adsorbed CO on partially oxidized Ru sites is postulated. Carbidic carbon atoms and alkyl species are observed on a Ru/TiO{sub 2} catalysts with {sup 13}C NMR and temperature-programmed surface reaction (TPSR). The carbidic carbon atoms are the precursors to methane and the monomer building blocks for hydrocarbon chains. Two types of alkyl species, C{beta}{prime} and C{beta}{double prime}, are formed from the carbidic carbon. The C{beta}{prime} is believed to consist of the intermediates to the C{sub 2+} hydrocarbon products. The C{beta}{double prime} is postulated to be long alkyl chains which accumulate on the catalysts support and are not involved in the reaction kinetics. Modeling of the steady-state and transient data suggest that the precursor to methane and the monomer building block are both formed directly from CO.
- Research Organization:
- California Univ., Berkeley, CA (USA)
- OSTI ID:
- 7035184
- Country of Publication:
- United States
- Language:
- English
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ADSORPTION
ALKANES
CARBON 13
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CONTROL
DESORPTION
ELEMENTS
EVEN-ODD NUCLEI
FOURIER TRANSFORMATION
HYDROCARBONS
HYDROGENATION
INFRARED SPECTRA
INTEGRAL TRANSFORMATIONS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MATHEMATICAL MODELS
METALS
METHANATION
METHANE
MINERALS
NUCLEAR MAGNETIC RESONANCE
NUCLEI
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
PRECURSOR
REACTION INTERMEDIATES
RESONANCE
RUTHENIUM
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SORPTION
SORPTIVE PROPERTIES
SPECTRA
STABLE ISOTOPES
STEADY-STATE CONDITIONS
SURFACE PROPERTIES
SYNTHESIS
TEMPERATURE CONTROL
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRACER TECHNIQUES
TRANSFORMATIONS
TRANSIENTS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS