Carbon and oxygen reaction pathways of CO{sub 2} reforming of methane over Ni/La{sub 2}O{sub 3}and Ni/Al{sub 2}O{sub 3} catalysts studied by isotopic tracing techniques

Journal Article · Fri Oct 01 04:00:00 EDT 1999 · Journal of Catalysis

DOI:https://doi.org/10.1006/jcat.1999.2565· OSTI ID:20000961

Tsipouriari, V A; Verykios, X E

Steady-state tracing techniques, using isotopically labeled molecules, were applied to study mechanistic aspects of the carbon and oxygen reaction pathways to form CO over Ni/La{sub 2}O{sub 3} and Ni/Al{sub 2}O{sub 3} catalysts. Over the Ni/La{sub 2}O{sub 3} catalyst, it was found that under steady-state reaction conditions, the quantity of reversibly adsorbed CH{sub 4} and the active carbon-containing intermediate species in the carbon pathway to form CO originating from CH{sub 4} is higher than the respective quantities derived from the CO{sub 2} molecule. Over the Ni/Al{sub 2}O{sub 3} catalyst, much smaller quantities of reversibly adsorbed CH{sub 4} and active carbon-containing species, originated from the CH{sub 4} molecule, which lead to CO formation were detected. It was also determined that a large quantity of oxygen atoms, originating from the La{sub 2}O{sub 3} support of the Ni/La{sub 2}O{sub 3} catalyst, participate in the reaction scheme. It is concluded that La{sub 2}O{sub 2}CO{sub 3}, which form by the interaction of La{sub 2}O{sub 3} and CO{sub 2}, may decompose to produce CO or provide oxygen species which react with carbon accumulated on Ni crystallites due to CH{sub 2} cracking to produce CO. The latter process is very fast over the Ni/La{sub 2}O{sub 3} catalyst, as compared to carbon accumulation, and this imparts this catalyst its special stability characteristics.

• Research Organization: Univ. of Patras (GR)
• OSTI ID: 20000961
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 187; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
10 SYNTHETIC FUELS
ALUMINIUM OXIDES
CARBON DIOXIDE
CATALYTIC EFFECTS
CHEMICAL REACTION KINETICS
LANTHANUM OXIDES
METHANE
NICKEL
REACTION INTERMEDIATES
REFORMER PROCESSES
SYNTHESIS GAS