CO hydrogenation on a nickel catalyst. I. Kinetics and modeling of a low temperature sintering process

Journal Article · Fri Jul 01 04:00:00 EDT 1994 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1994.1180· OSTI ID:6859208

Agnelli, M; Mirodatos, C ^[1]; Kolb, M ^[2]

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1. Institut de Recherches sur la Catalyse, Villeurbanne (France)
2. Institut de Recherches sur la Catalyse, Villeurbanne (France) Ecole Normale Superieure de Lyon (France)

Sintering of a Ni/SiO[sub 2] catalyst was studied under methanation conditions. The loss of metallic surface, accounting for the catalyst deactivation, was shown to come from the migration of nickel subcarbonyl adspecies formed during the reaction. The catalyst, presenting initially a bimodal Ni particle size distribution, evolved towards a bimodal system consisting of small spherical and large faceted crystals, with a selective development of <111> planes after several hours under reaction conditions. The formation of a nickel carbide monolayer could interfere with the formation of the large particles, possibly by decreasing the concentration of the mobile subcarbonyl adspecies. The best description of the observed sintering process was provided by considering a model with two distinct species, evolving according to the Ostwald-ripening mechanism, and being coupled by mass transport through the mobile nickel subcarbonyl intermediates. Long-term simulations allowed for the prediction of the ultimate state of the catalyst, and solutions aimed at slowing down the loss of nickel surface was proposed. 24 refs., 9 figs., 9 tabs.

• OSTI ID: 6859208
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 148:1; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

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CARBON COMPOUNDS
CARBON MONOXIDE
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CATALYSIS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
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KINETICS
METALS
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OXYGEN COMPOUNDS
REACTION INTERMEDIATES
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