Adsorption, desorption, and reactions of carbon monoxide, oxygen, and nitric oxide on clean polycrystalline rhodium surfaces
The adsorption, desorption, and reactions of carbon monoxide, oxygen, and nitric oxide on clean polycrystalline rhodium surfaces were studied in an ultrahigh vacuum apparatus. Carbon monoxide adsorbed with near-unit sticking probability and a heat of adsorption of approx. 31 kcal/mole; it desorbed at about 540/sup 0/K with an activation energy equal to its heat of adsorption and a frequency factor near 3 x 10/sup 13//sec. Oxygen chemisorbed with an initial sticking probability of 0.25 and produced chemisorbed oxygen atoms on the surface. Chemisorbed oxygen reacted with gas-phase carbon monoxide to give carbon dioxide with almost unit reaction probability at 440/sup 0/K, in contrast to preadsorbed carbon monoxide which was almost inert to gas-phase oxygen at 330/sup 0/K. The carbon monoxide oxidation reaction proceeded by a Langmuir-Hinshelwood combination of coadsorbed oxygen and carbon monoxide with an activation energy of approx. 14.3 kcal/mole below 530/sup 0/K and 25 kcal/mole above. Nitric oxide chemisorbed on clean rhodium at 330/sup 0/K to produce a mixture of molecular (-NO) and dissociated (-N and -O) adspecies. Carbon monoxide reacted with NO to produce carbon dioxide and nitrogen.
- OSTI ID:
- 6462976
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ACTIVATION ENERGY
ADSORPTION HEAT
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISORPTION
DATA
DESORPTION
ELEMENTS
ENERGY
ENTHALPY
EXPERIMENTAL DATA
INFORMATION
KINETICS
METALS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
NONMETALS
NUMERICAL DATA
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLATINUM METALS
REACTION KINETICS
RHODIUM
SEPARATION PROCESSES
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
SURFACES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS