Catalytic behavior of transition metal oxide in graphite gasification by oxygen, water, and carbon dioxide

Journal Article · Mon Jul 01 04:00:00 EDT 1991 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(91)90100-I· OSTI ID:5455393

Pan, Z J; Yang, R T ^[1]

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

Vanadium oxide is used as a model transition metal-oxide catalyst for the gasification of graphite by O{sub 2}, H{sub 2}O, and CO{sub 2}. The following catalyst actions on the graphite basal plane are common in all three reactions: deep layer channeling, monolayer channeling, edge recession, and widening monolayer channeling. The steady-state oxidation states of vanadium in the reactions with CO{sub 2} and H{sub 2}O are, respectively, V{sub 3}O{sub 5} and V{sub 2}O{sub 3} under the reaction conditions. The rate-limiting step in all channeling actions (for all three gasification reactions) is oxidation on the surface of the metal-oxide to increase the oxygen activity. Oxygen then diffuses through the nonstoichiometric metal-oxide particle to reach the carbon active sites where gasification takes place. (However, based on the channeling and TGA rate data, the catalyst surface oxidation is the rate-limiting step; the subsequent steps of diffusion of oxygen anion and C-C bond breakage steps are not rate-limiting.) This mechanism can explain the fact that transition metal-oxides are the most active catalysts for the C + O{sub 2} reaction but are only weakly active for the C + H{sub 2}O and C + CO{sub 2} reactions. The origin of the phenomenon of the widening monolayer channels is attributed to the anisotropy of the catalyzed reactivities of two adjacent zigzag edges of graphite.

• OSTI ID: 5455393
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 130:1; 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
ANISOTROPY
CARBON
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CLEAVAGE
COAL GASIFICATION
COMPARATIVE EVALUATIONS
CRYSTAL STRUCTURE
DIFFUSION
ELEMENTAL MINERALS
ELEMENTS
ENERGY
GASIFICATION
GRAPHITE
GRAVIMETRIC ANALYSIS
HYDROGEN COMPOUNDS
KINETICS
MICROSTRUCTURE
MINERALS
NONMETALS
OXIDATION
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHASE STUDIES
QUANTITATIVE CHEMICAL ANALYSIS
REACTION KINETICS
SURFACE PROPERTIES
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
VANADIUM COMPOUNDS
VANADIUM OXIDES
WATER