The mechanism of methane formation from the reaction between graphite and hydrogen

Journal Article · Tue May 01 00:00:00 EDT 1990 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(90)90169-K· OSTI ID:6224345

Pan, Z J; Yang, R T ^[1]

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1. State Univ. of New York, Buffalo (USA)

Monolayer etch pits formed on the basal plane of graphite by hydrogen are hexagonal in shape and are bounded by (10{anti 1}l) zigzag edge faces. The reaction is also studied by using extended Hueckel molecular orbital (EHMO) calculations with geometry optimization, where H atoms are added to the edge surface carbon and these carbon atoms are allowed to deform from the original positions corresponding to the graphite structure to reach the equilibrium positions. The EHMO/geometry optimization results indicate that the zigzag edge face is more reactive than the (11{anti 2}l) armchair face before and after one H is chemisorbed on the surface atom. However, a reversal in the relative reactivity occurs after the second H addition; the C-C bond on the armchair face becomes weaker and carbon atoms become more reactive for the third H chemisorption. Breakage of C-C bonds takes place upon the third H addition, and this step is the rate-limiting step for CH{sub 4} formation.

• OSTI ID: 6224345
• Journal Information: Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 123:1; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404* -- Coal
Lignite
& Peat-- Gasification
ACTIVATION ENERGY
ALKANES
CARBON
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISORPTION
COAL GASIFICATION
CRYSTAL STRUCTURE
ELEMENTAL MINERALS
ELEMENTS
ENERGY
GASIFICATION
GRAPHITE
HYDROCARBONS
HYDROGEN
HYDROGENATION
KINETICS
METHANE
MINERALS
MOLECULAR ORBITAL METHOD
NONMETALS
ORGANIC COMPOUNDS
REACTION KINETICS
SEPARATION PROCESSES
SORPTION
SYNTHESIS
THERMOCHEMICAL PROCESSES