Hydrogenation of CO/sub 2/ on group VIII metals II. Kinetics and mechanism of CO/sub 2/ hydrogenation on nickel
The rate of CO/sub 2/ hydrogenation on Ni/SiO/sub 2/ was measured as a function of H/sub 2/ and CO/sub 2/ partial pressures at 500-600 K, 140 kPa, and 30,000-90,000 h/sup -1/. The data show that the rate of CO/sub 2/ hydrogenation is moderately dependent on CO/sub 2/ and H/sub 2/ concentrations at low partial pressures but essentially concentration independent at high partial pressures. Under most typical reaction conditions CO is observed as a product of the reaction at levels determined by quasi-equilibrium between surface and gas phase CO species. Addition of CO to the reactants above this equilibrium level causes a significant decrease in the rate of CO/sub 2/ hydrogenation apparently as a result of product inhibition. Reaction orders and the true activation energy are quite temperature dependent indicating that a simple power law rate expression provides an inadequate fit of the data. Indeed, the kinetic results are consistent with a complex Langmuir-Hinshelwood mechanism involving dissociative adsorption of CO/sub 2/ to CO and atomic oxygen followed by hydrogenation of CO via a carbon intermediate to methane.
- Research Organization:
- Brigham Young Univ., Provo, UT
- OSTI ID:
- 6540087
- Journal Information:
- J. Catal.; (United States), Vol. 77:2
- Country of Publication:
- United States
- Language:
- English
Similar Records
CO disproportionation on silica-supported nickel and nickel-copper catalysts
Kinetic and reaction engineering studies of dry reforming of methane over a Ni/La/Al{sub 2}O{sub 3} catalyst
Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBON DIOXIDE
METHANATION
CATALYSTS
METHANE
SYNTHESIS
NICKEL COMPLEXES
CATALYTIC EFFECTS
ACTIVATION ENERGY
CHEMICAL REACTION KINETICS
HYDROGENATION
SILICON OXIDES
ALKANES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
COMPLEXES
ENERGY
HYDROCARBONS
KINETICS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
SILICON COMPOUNDS
TRANSITION ELEMENT COMPLEXES
090100* - Hydrocarbon Fuels- (-1989)
400100 - Analytical & Separations Chemistry
400201 - Chemical & Physicochemical Properties