Hydrogenation of surface carbon on alumina-supported nickel
Four types of carbon were observed to form on an alumina-supported nickel methanation catalyst on exposure to carbon monoxide at 550 +- 50 K. In order of their reactivity toward hydrogen the carbon species may be classified as: chemisorbed carbon atoms (..cap alpha..), bulk nickel carbide, amorphous carbon (..beta..), and crystalline elemental carbon. The ..cap alpha..-phase and initial monolayers of Ni/sub 3/C are much mre reactive than the elemental forms as measured by temperature-programmed surface reaction in 100 kPa H/sub 2/. At 550 K the ..cap alpha..- and ..beta..-carbon species formed by CO exposure populate the surface at a ratio of about 2:1. Both phases are relatively stable on heating to 600 K in a He atmosphere. At higher temperatures, slow conversion of ..cap alpha..- and ..beta..-carbon to graphite was oserved. Hydrogenation of the ..cap alpha.. state at 550 K leads to methane at a sufficiently fast rate to make it a likely intermediate in nickel-catalyzed methane synthesis from hydrogen and carbon monoxide.
- Research Organization:
- SRI International, Menlo Park, CA
- OSTI ID:
- 6274427
- Journal Information:
- J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 57:3; ISSN JCTLA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Deactivation of surface carbon on alumina supported nickel
Deactivation of alumina-supported nickel and ruthenium catalysts by sulfur compounds
Related Subjects
10 SYNTHETIC FUELS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBIDES
CARBON
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMICAL STATE
CHEMISORPTION
ELEMENTS
KINETICS
METALS
METHANATION
NICKEL
NICKEL CARBIDES
NICKEL COMPOUNDS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
REACTION INTERMEDIATES
REACTION KINETICS
SEPARATION PROCESSES
SORPTION
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS