Fischer-Tropsch synthesis over iron-rhodium alloy catalysts

Thesis/Dissertation · Fri Dec 31 23:00:00 EST 1982

OSTI ID:6714002

Choi, S

To investigate the nature of iron-rhodium alloy catalysts during the Fischer-Tropsch synthesis, a combination of experimental techniques were applied. Infrared spectroscopy was mainly used to extract direct information on the surface of catalysts under the reaction conditions. In addition, Mossbauer spectroscopy was employed to study the iron alloy catalysts. Further characterization of the catalysts was performed by chemisorption measurements. Hydrocarbon products of the CO + H/sub 2/ synthesis reaction were analyzed by gas chromatography. The working surface of a silica-supported rhodium catalyst was found to be saturated with molecular carbon monoxide. The intensity of the linear carbonyl absorption band remained constant compared to that for room temperature CO adsorption, while that of the bridge-bonded carbonyl absorption band was drastically reduced during the Fischer-Tropsch synthesis. The bridge-bonded adsorption sites are assumed to be the active sites for dissociating carbon monoxide. The hydrogenation rate of the linearly adsorbed carbon monoxide was much slower than the steady state reaction rate. The alloy catalyst did not form a bulk carbide, but the presence of surface carbon was suggested by the large shift of the linear carbonyl absorption band. On the other hand, infrared spectra on an iron catalyst showed only weak bands, indicating a high degree of CO dissociation. On a silica-supported iron-rhodium alloy catalyst, surface analysis by infrared spectroscopy presents evidence of well-mixed alloy formation. Three models of carbon monoxide adsorption were identified.

• OSTI ID: 6714002
• Country of Publication: United States
• Language: English

Related Subjects

090121* -- Hydrocarbon Fuels-- Chemical Synthesis-- (1976-1989)
10 SYNTHETIC FUELS
ALLOYS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHROMATOGRAPHY
ELEMENTS
FISCHER-TROPSCH SYNTHESIS
GAS CHROMATOGRAPHY
HYDROCARBONS
HYDROGEN
INFRARED SPECTROMETERS
IRON ALLOYS
MEASURING INSTRUMENTS
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METAL ALLOYS
RHODIUM ALLOYS
SEPARATION PROCESSES
SPECTROMETERS