Interaction of physisorbed species with chemisorbed species as studied by infrared spectroscopy
Infrared spectroscopy has been used to study the physical adsorption of CO onto a Rh/Al/sub 2/O/sub 3/ surface. In addition to absorption bands related to monolayer and multilayer physisorbed CO species, an interaction between the physisorbed species and chemisorbed CO has been observed causing a decrease of the chemisorbed CO wavenumber. Similar effects between physisorbed Xe and chemisorbed N/sub 2/ on Rh surfaces have also been observed, suggesting that the effect is a general one. Correlation of these measurements with measurements of CO trapped in CO matrices suggests that inductive and dispersive effects are the main factors responsible for the negative shift in chemisorbed species wavenumber. It has been found that physisorbed CO preferentially adsorbs in the vicinity of ionic sites, and that the change in entropy of adsorption is approximately equal to 5.6 +/- 2 kcal mol/sup -1/ for CO physisorption near Rh/sup I/(CO)/sub 2/ species.
- Research Organization:
- National Bureau of Standards, Washington, DC
- OSTI ID:
- 6054337
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 88:20; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ADSORPTION
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISORPTION
DATA
ELEMENTS
EXPERIMENTAL DATA
FLUIDS
GASES
INFORMATION
INFRARED SPECTRA
METALS
NITROGEN
NONMETALS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
RARE GASES
RHODIUM
SEPARATION PROCESSES
SORPTION
SORPTIVE PROPERTIES
SPECTRA
SURFACE PROPERTIES
THERMODYNAMICS
TRANSITION ELEMENTS
XENON