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An original growth mode of MWCNTs on alumina supported iron catalysts

Philippe, Régis and Caussat, Brigitte and Falqui, A. and Kihn, Yolande and Kalck, Philippe and Bordère, Serge and Plee, Dominique and Gaillard, Patrice and Bernard, Daniel and Serp, Philippe An original growth mode of MWCNTs on alumina supported iron catalysts. (2009) Journal of Catalysis, vol. 2 (n° 2). pp. 345-358. ISSN 0021-9517

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Official URL: http://dx.doi.org/10.1016/j.jcat.2009.02.027

Abstract

Multi-walled carbon nanotubes (MWCNTs) have been produced from ethylene by Fluidized Bed Catalytic Chemical Vapor Deposition (FB-CCVD) on alumina supported iron catalyst powders. Both catalysts and MWCNTs-catalyst composites have been characterized by XRD, SEM-EDX, TEM, Mössbauer Spectroscopy, TGA and nitrogen adsorption measurements at different stages of the process. The fresh catalyst is composed of amorphous iron (III) oxide nanoparticles located inside the porosity of the support and of a micrometric crystalline &-iron (III) oxide surface film. The beginning of the CVD process provokes a brutal reconstruction and simultaneous carburization of the surface film that allows MWCNT nucleation and growth. These MWCNTs grow aligned between the support and the surface catalytic film, leading to a uniform consumption and uprising of the film. When the catalytic film has been consumed, the catalytic particles located inside the alumina porosity are slowly reduced and activated leading to a secondary MWCNT growth regime, which produces a generalized grain explosion and entangled MWCNT growth. Based on experimental observations and characterizations, this original two-stage growth mode is discussed and a general growth mechanism is proposed.

Item Type:Article
Additional Information:Thanks to Elsevier editor. The definitive version is available at http://www.sciencedirect.com The original PDF of the article can be found at Journal of Catalysis website : http://www.sciencedirect.com/science/journal/00219517
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > Instituto Italiano di Tecnologia - IIT (ITALY)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
Other partners > Arkema (FRANCE)
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS
French research institutions > Centre National de la Recherche Scientifique - CNRS
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Deposited By: Brigitte CAUSSAT-BONNANS
Deposited On:18 Jun 2009 08:01

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