Carbon-13 NMR studies of CO adsorbed on supported platinum and palladium catalysts using magic angle sample spinning
- Yale Univ., New Haven, CT (USA)
- Universite Pierre et Marie Curie, Paris (France)
The {sup 13}C solid-state NMR of {sup 13}CO chemisorbed on supported Pt and Pd catalysts has been investigated by static and magic angle spinning (MAS) NMR methods. The observation of a significant Knight shift of the {sup 13}C resonance by other workers is confirmed for both Pt and Pd catalysts. The sources of line broadening for the static pattern have been reinvestigated and the ultimate resolution by MAS methods has been tested. On Pd the CO is motionally narrowed by rapid diffusion on the surface at room temperature, giving a relatively narrow line unaffected by MAS. Several possibilities are discussed for the source of the shift distribution, including the effects of stable paramagnetic sites or a distribution in isotropic Knight shifts. These measurements and previous bulk susceptibility measurements are analyzed with respect to the resolution in other catalyst systems. Experimental support for a two-stage diffusion model in which the rate-limiting step is edge-to-face conversion is also discussed.
- OSTI ID:
- 6712428
- Journal Information:
- Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 94:4; ISSN 0022-3654; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
Similar Records
NMR of platinum catalysts: Double NMR of chemisorbed carbon monoxide and a model for the platinum NMR line shape
Correlation between the Knight shift of chemisorbed CO and the Fermi level local density of states at clean platinum catalyst surfaces
Related Subjects
400201* -- Chemical & Physicochemical Properties
ADSORPTION
CALCULATION METHODS
CARBON 13
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CHALCOGENIDES
DATA
DATA ANALYSIS
ELEMENTS
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
INFORMATION
ISOTOPES
LIGHT NUCLEI
MEASURING INSTRUMENTS
MEASURING METHODS
METALS
NMR SPECTRA
NUCLEI
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PALLADIUM
PLATINUM
PLATINUM METALS
SORPTION
SPECTRA
STABLE ISOTOPES
TRANSITION ELEMENTS