Adsorbed states of CO on dispersed metals: quantitative analysis with /sup 13/C NMR spectroscopy

Journal Article · Thu Jul 28 04:00:00 EDT 1988 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100326a036· OSTI ID:6187343

Duncan, T M; Root, T W

The /sup 13/C NMR spectra of CO adsorbed on silica-supported Ru and Rh provide quantitative analysis and descriptions of the three adsorbed states: linear- and bridge-bonded CO on metal particles and multicarbonyls on isolated metal atoms. Isolated Rh atoms adsorb two CO's, and the multicarbonyls on Ru have two or three CO's per Ru. The species adsorbed on the metal particles are immobile at 295 K (on the NMR time scale of a few milliseconds) whereas the multicarbonyls are motionally averaged. The ratio of linear to bridging CO on Ru particles is approx. 4:1. On Rh/silica, this ratio is 1:1.5. The isolated Rh atoms are not paramagnetic, which indicates that migration from the metal particles to form dicarbonyls is accompanied by oxidation of the Rh atom. At least two metal particle morphologies, spheres and rafts, are consistent with the CO site distributions, the overall CO-to-metal ratio, and the local density of CO measured by /sup 13/C NMR spectroscopy.

• Research Organization: ATandT Bell Labs., Murray Hill, NJ (USA)
• OSTI ID: 6187343
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 92:15; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CARBON 13
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON MONOXIDE
CARBON OXIDES
CATALYSIS
CHALCOGENIDES
DATA
ELEMENTS
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
INFORMATION
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
METALS
MINERALS
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PARTICLE SIZE
PARTICLES
PLATINUM METALS
RESONANCE
RHODIUM
RUTHENIUM
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SIZE
SORPTION
SORPTIVE PROPERTIES
STABLE ISOTOPES
SURFACE PROPERTIES
TRANSITION ELEMENTS