Dresden 2003 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 11: Kohlenstoff-Nanoröhrchen
CPP 11.1: Vortrag
Donnerstag, 27. März 2003, 11:30–11:45, ZEU/160
Complete elimination of metal catalysts from single wall carbon nanotubes by oxidation treatment — •Badis Bendjemil1,2, Ewa Boroviak-Palen 1, O. Jost 3, A. Graff1, T. Pichler1, M. Guerioune2, M. Knupfer1, and J. Fink1 — 1Leibniz Institut für Festkörper- und Werkstofforschung — 2University Badji-Mokhtar Annaba, Faculty of Sciences, Institute of Physics, Laboratory Study and Research of Condensed Matter, Algeria. — 3Institute of Material Science, Dresden University of Technology, Germany.
Single-wall carbon nanotubes (SWCNT) produced by laser ablation with 70 wt%. They also contain other carbonaceous species and catalyst particles (up to 25 wt% Ni/Co). For purification we performed an oxidation treatment in the temperature range between 450oC and 750oC under varying partial oxygen pressure (5.10−6 to 9.10−5 mbar) and oxidation time (24-120 h). The purification and the evolution upon this oxidation treatments are monitored by optical absorption spectroscopy, TEM/EELS and electron diffraction. The optimal purification conditions is observed for a temperature of 650oC, a partial oxygen pressure of 9.10−5 mbar and a time oxidation of 96 hours. A significant shift to lower energy is observed for the optical absorption peaks. This can be explained by the removal of the SWCNT with smaller diameters. After oxidation the amorphous carbon is removed and the sample is non magnetic because the encaged catalyst impurities are completely oxidized. These NiO and CoO particles were removed by HCl washing. Finally, in order to obtain high purity SWCNTs with good crystallinity the samples were heated under high vacuum.