Fluorination of carbon nanotubes Original Research Article

Carbon nanotubes were prepared by thermal decomposition of acetylene over silica-supported cobalt catalysts. Subsequent chemical treatments with concentrated hydrofluoric acid and dilute nitric acid, respectively, eliminated the silica substrate and the remaining catalyst. The complete removal of cobalt was very difficult due to encapsulation of part of it in the shells, but a graphitization at 2800 °C eliminated the rest of cobalt and the structural defects. The reactivity of carbon nanotubes with fluorine was studied and compared to that of graphite. Important modification of the nanotubes structure was observed after reaction at high temperature as against the behaviour observed during reaction at room temperature. Compounds were analysed by means of transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy.