Multiwall carbon nanotubes grown by the catalytic
decomposition of acetylene over supported Co
catalyst were subjected to wet and
dry oxidation in order to remove the unwanted
products and the catalyst traces. The effects of
the purification treatment on the Co content
was monitored by physical methods:
Rutherford Backscattering Spectrometry (RBS),
Particle Induced X-Ray Emission (PIXE) and
X-Ray Fluorescence (XRF). The purified products
were investigated by microscopic methods: TEM, Scanning Electron Microscopy (SEM),
Energy Dispersive Spectroscopy (EDS) and STM.
The KMnO4/H2SO4 aqueous oxidation procedure was
found to be effective in reducing the Co content
while damaging only moderately the outer wall of
the nanotubes. Treatment in HNO3/H2SO4 yields
a bucky-paper like product and produces the increase of the Si and S content of the sample.
