caa a22 4500 463223705 CHVBK 20180405153220.0 cr unu---uuuuu 170326e20071001xx s 000 0 eng 10.1007/s10853-007-1808-2 doi (NATIONALLICENCE)springer-10.1007/s10853-007-1808-2 Synthesis and characterization of carbon nanotubes grown on montmorillonite clay catalysts [Elektronische Daten] [Alexandra Destrée, Gary Long, Benjamin Vatovez, Fernande Grandjean, Antonio Fonseca, Janos Nagy, A.-M. Fransolet] Multiwall carbon nanotubes have been grown on montmorillonite clay catalysts through anchoring on FeCo nanoparticles. The starting clay is a commercial sodium-rich montmorillonite in which the intercalated sodium ion was exchanged for cobalt(II) and iron(III) ions via mechanical agitation or sonication, both with and without subsequent centrifugation. The cobalt-iron intercalate clay was used as a catalyst for the synthesis of carbon nanotubes via decomposition of ethylene at 700°C. The largest carbon deposit was obtained for catalysts prepared with 3 or 4 cation exchange equivalents. X-ray diffraction indicates both that the basal spacing of the clay increases from 12.43Å to 16.4Å upon intercalation of cobalt and iron. Atomic absorption analysis of the catalysts indicates that virtually all of the sodium ions originally present in the clay have been replaced by iron(III) and cobalt(II). Transmission electron micrographs show the presence of multiwall carbon nanotubes with inner and outer diameters of ca. 10nm and 20nm grown on metal particles present on the plates of catalysts. The iron-57 Mössbauer spectra indicate that the intercalated clay contains iron(III) in octahedral and tetrahedral sites and iron(II) in octahedral sites, the catalysts contain an extensive amount of small superparamagnetic particles of α-Fe2O3 and that the carbon-nanotube catalyst composites show the presence of iron(II) and iron(III) paramagnetic doublets, characteristic of a reduced montmorillonite, and of sextets that are characteristic of an FeCo alloy and of Fe3C cementite. The Mössbauer spectra indicate that the carbon nanotubes grow on FeCo metallic nanoparticles and bond to these particles through the formation of cementite. Springer Science+Business Media, LLC, 2007 Destrée Alexandra Facultés Universitaires Notre-Dame de la Paix, 61, rue de Bruxelles, 5000, Namur, Belgium aut Long Gary Department of Chemistry, University of Missouri-Rolla, 65409-0010, Rolla, MO, USA aut Vatovez Benjamin Department of Physics, University of Liège, B5, 4000, Sart-Tilman, Belgium aut Grandjean Fernande Department of Physics, University of Liège, B5, 4000, Sart-Tilman, Belgium aut Fonseca Antonio Facultés Universitaires Notre-Dame de la Paix, 61, rue de Bruxelles, 5000, Namur, Belgium aut Nagy Janos Facultés Universitaires Notre-Dame de la Paix, 61, rue de Bruxelles, 5000, Namur, Belgium aut Fransolet A.-M Department of Geology, University of Liège, B18, 4000, Sart-Tilman, Belgium aut Journal of Materials Science Springer US; http://www.springer-ny.com 42/20(2007-10-01), 8671-8689 0022-2461 42:20<8671 2007 42 10853 https://doi.org/10.1007/s10853-007-1808-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10853-007-1808-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Destrée Alexandra Facultés Universitaires Notre-Dame de la Paix, 61, rue de Bruxelles, 5000, Namur, Belgium aut NATIONALLICENCE 700 1- Long Gary Department of Chemistry, University of Missouri-Rolla, 65409-0010, Rolla, MO, USA aut NATIONALLICENCE 700 1- Vatovez Benjamin Department of Physics, University of Liège, B5, 4000, Sart-Tilman, Belgium aut NATIONALLICENCE 700 1- Grandjean Fernande Department of Physics, University of Liège, B5, 4000, Sart-Tilman, Belgium aut NATIONALLICENCE 700 1- Fonseca Antonio Facultés Universitaires Notre-Dame de la Paix, 61, rue de Bruxelles, 5000, Namur, Belgium aut NATIONALLICENCE 700 1- Nagy Janos Facultés Universitaires Notre-Dame de la Paix, 61, rue de Bruxelles, 5000, Namur, Belgium aut NATIONALLICENCE 700 1- Fransolet A.-M Department of Geology, University of Liège, B18, 4000, Sart-Tilman, Belgium aut NATIONALLICENCE 773 0- Journal of Materials Science Springer US; http://www.springer-ny.com 42/20(2007-10-01), 8671-8689 0022-2461 42:20<8671 2007 42 10853 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer