Hydrogenation of surface carbon on alumina-supported nickel

Journal Article · Tue May 01 04:00:00 EDT 1979 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(79)90007-1· OSTI ID:6675932

Mccarthy, J G; Wise, H

The methanation of carbon deposited by CO or ethylene decomposition on Girdler G-65 catalyst (25Vertical Bar3< nickel, 8Vertical Bar3< alkali, mostly CaO, 4Vertical Bar3< C as graphite, on alumina) was studied by temperature-programed desorption and temperature-programed surface reaction. Four types of carbon were identified: ..cap alpha..-carbon consisted of isolated carbon atoms bonded to nickel and reacting with hydrogen at 470/sup 0/ +/- 20/sup 0/K; ..gamma..-carbon was probably a bulk carbide, most likely Ni/sub 3/C, which had a reaction peak at 550/sup 0/K; ..beta..-carbon consisted of amorphous, polymerized carbon, which had a reaction peak at 680/sup 0/K; and an unreactive crystalline graphite-like species. The ..cap alpha..-form was thermally unstable and transformed into the ..beta..-form above 600/sup 0/K. Both ..cap alpha..- and ..beta..-forms slowly converted to inert graphite above 600/sup 0/K. The evidence suggested that synthesis gas methanation proceeds by dissociative adsorption of CO as the rate-determining step which forms a very reactive carbon adatom state (..cap alpha..') which converts to the ..cap alpha..-state in the absence of hydrogen and to methane in the presence of hydrogen.

• Research Organization: Sri Int.
• OSTI ID: 6675932
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 57:3; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical &amp; Physicochemical Properties
CARBON
CATALYSTS
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
CRYSTAL STRUCTURE
ELEMENTS
HYDROGENATION
METALS
NICKEL
NONMETALS
STRUCTURAL CHEMICAL ANALYSIS
THERMAL ANALYSIS
TRANSITION ELEMENTS