CO hydrogenation over rhodium foil and single crystal catalysts: correlations of catalyst activity, selectivity, and surface composition

Conference · Mon Jan 01 04:00:00 EST 1979 · Am. Chem. Soc., Div. Fuel Chem., Prepr.; (United States)

OSTI ID:5171043

Castner, D G; Blackadar, R L; Somorjai, G A

CO hydrogenation at 6 atm over polycrystalline Rh foil and single crystal Rh (111) catalysts was investigated in a system where the surface structure and composition of the catalysts could be characterized both before and after the reaction. The reaction conditions (H/sub 2/:CO ratio, reaction temperature, and surface pretreatment) were systematically varied to determine the optimum conditions for formation of oxygenated hydrocarbons. Initially clean Rh catalysts showed no structure sensitivity, primarily produced methane (90 wt%) at an initial rate of 0.15 molecules site/sup -1/ sec /sup -1/ at 300/sup 0/C, and did not produce detectable amounts of oxygenated hydrocarbons. Preoxidation of the Rh catalysts (800 Torr O/sub 2/, 600/sup 0/C, 30 min.) resulted in dramatically increased initial rates, a larger fraction of higher molecular weight hydrocarbons, some structure sensitivity, and formation of methanol, ethanol, and acetaldehyde. The different Arrhenius parameters over the clean and preoxidized foils indicate that the methanation mechanism is different on these two surfaces. Decreasing the reaction temperature of H/sub 2/:CO ratio increased the C/sub 2/H/sub 4/ to C/sub 2/H/sub 6/ ratio and shifted the product distribution towards higher molecular weight hydrocarbons.

• Research Organization: Univ. of California, Berkeley
• OSTI ID: 5171043
• Report Number(s): CONF-800303-P3
• Conference Information: Journal Name: Am. Chem. Soc., Div. Fuel Chem., Prepr.; (United States) Journal Volume: 25:2
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
ACETALDEHYDE
ALCOHOLS
ALDEHYDES
ALKANES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CRYOGENIC FLUIDS
DATA
DATA FORMS
ELEMENTS
ETHANOL
EXPERIMENTAL DATA
FISCHER-TROPSCH SYNTHESIS
FLUIDS
GRAPHS
HYDROCARBONS
HYDROGENATION
HYDROXY COMPOUNDS
INFORMATION
METALS
METHANE
METHANOL
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
REFRACTORY METALS
RHODIUM
SPECIFICITY
TABLES
TRANSITION ELEMENTS