Adsorption and reaction of CO and H/sub 2/ on K-promoted Rh/SiO/sub 2/ catalysts
The adsorption of CO and H/sub 2/ on a series of alkali-promoted Rh/SiO/sub 2/ catalysts was investigated by IR spectroscopy and volumetric chemisorption. The characteristics of the support as well as the method of addition of the alkali species were found to influence the adsorptive properties of the catalysts. Alkali species on wide-pore Rh/SiO/sub 2/ tended to partition to the support and did not interact strongly with the Rh crystallites. When alkali and metal salts were coimpregnated onto a nonporous SiO/sub 2/ support, intimate alkali-metal contact resulted in significant electronic interactions between the alkali species and the metal. When alkali species were added to a prereduced Rh/SiO/sub 2/ (nonporous) catalyst, a chemical interaction between a tilted adsorbed CO and the alkali species was suggested. The nature and location of the alkali species were suggested to be important parameters in determining the effect of alkali promoters on Rh/SiO/sub 2/ catalysts. The rate of CO conversion decreased substantially with promotion for all of the promoted catalysts. An unusually low apparent activation energy was found for the sequentially impregnated (nonporous SiO/sub 2/) promoted catalyst, and it was suggested that this might be related to the unusually low frequency peak seen in the IR spectrum of adsorbed CO on this catalyst.
- Research Organization:
- Univ. of Pittsburgh, PA
- OSTI ID:
- 5469137
- Journal Information:
- J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 105:2; ISSN JCTLA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010408* -- Coal
Lignite
& Peat-- C1 Processes-- (1987-)
ACTIVATION ENERGY
ADSORPTION
ALKALI METALS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYSTS
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
ENERGY
HYDROGEN
HYDROGENATION
INFRARED SPECTRA
METALS
MINERALS
NONMETALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
POROSITY
POTASSIUM
PROMOTERS
RHODIUM
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SORPTION
SORPTIVE PROPERTIES
SPECTRA
SURFACE PROPERTIES
TRANSITION ELEMENTS