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A Study of the Formation of Single- and Double-Walled Carbon Nanotubes by a CVD Method

Peigney, Alain and Coquay, Pierre and Flahaut, Emmanuel and Vandenberghe, Robert E. and De Grave, Eddy and Laurent, Christophe A Study of the Formation of Single- and Double-Walled Carbon Nanotubes by a CVD Method. (2001) The Journal of Physical Chemistry B, vol. 105 (n° 40). pp. 9699-9710. ISSN 1520-6106

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Official URL: http://dx.doi.org/10.1021/jp004586n

Abstract

The reduction in H2/CH4 atmosphere of aluminum-iron oxides produces metal particles small enough to catalyze the formation of single-walled carbon nanotubes. Several experiments have been made using the same temperature profile and changing only the maximum temperature (800-1070 °C). Characterizations of the catalyst materials are performed using notably 57Fe Mo¨ssbauer spectroscopy. Electron microscopy and a macroscopical method are used to characterize the nanotubes. The nature of the iron species (Fe3+, R-Fe, ç-Fe-C, Fe3C) is correlated to their location in the material. The nature of the particles responsible for the high-temperature formation of the nanotubes is probably an Fe-C alloy which is, however, found as Fe3C by postreaction analysis. Increasing the reduction temperature increases the reduction yield and thus favors the formation of surface-metal particles, thus producing more nanotubes. The obtained carbon nanotubes are mostly single-walled and double-walled with an average diameter close to 2.5 nm. Several formation mechanisms are thought to be active. In particular, it is shown that the second wall can grow inside the first one but that subsequent ones are formed outside. It is also possible that under given experimental conditions, the smallest (<2 nm) catalyst particles preferentially produce double-walled rather than single-walled carbon nanotubes.

Item Type:Article
Additional Information:Thanks to American Chemical Society editor. The original PDF of the article can be found at The Journal of Physical Chemistry B website : http://pubs.acs.org/journal/jpcbfk
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
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Deposited By: cirimat webmestre
Deposited On:06 Dec 2013 14:15

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