Fullerenes and Carbon Nanotubes Formed in an Electric Arc at and Above Atmospheric Pressure

Abstract [60]Fullerene and carbon nanotubes have been obtained with an electric arc discharge in helium or argon at the pressure of 0.1–3.0 bar (i.e. from −0.9 up to 2.0 bar above the atmospheric pressure, respectively). The yield of the process is about 10 times higher in helium with a maximum at the pressure of 0.2 bar, while in argon the maximum is observed at 0.4 bar. It is not very important, what kind of the inert gas (He or Ar) is used in a process carried out at the atmospheric pressure and higher. In this case, the yield is usually better or comparable with other alternative methods, e.g. the solar furnace synthesis. We found that the oxygen plays a crucial role reducing the yield of fullerenes and carbon nanotubes. Even traces of O2 must be removed from the reactor chamber, otherwise yellow coloured fullerene derivatives (oxidation products) are formed instead of C60.