Authors: L.F. Giraldo, B.L. López and G.M. Barrera
Affilation: Universidad de Antioquia, Colombia
Pages: 92 - 95
Keywords: carbon nanotubes, thermal stability, CCVD
In the synthesis of carbon nanotubes two of the most important parameters to consider are the type of support and the kind of catalytic metal. In this work we have studied the thermal stability of multiwall carbon nanotubes produced by catalytic deposition of ethylene by using CaCO3, MgO and MCM41mesoporous silica as supports of metallic particles of Fe and Co. The samples are characterized by scanning and transmission electron microscopy, thermal analysis and X-ray diffraction. We find that the type of the support is an important factor in the efficiency and nature of the nanotube obtained. The amount of nanotubes obtained is higher when CaCO3 is utilized as support; however the structural regularity of the material produced is lower than the nanotubes obtained by using mesoporous materials and the MgO as supports. The synthesized material has 70 % nanotubes when the CaCO3 is used as support of 6 wt % Fe and 12 wt % Co as catalytic metals. For the same catalyst and reaction conditions, an increase in the flow of ethylene increase the length of the nanotubes, this is reflected in the efficiency, but it does not seem to modify the nanotube diameter.
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