INFLUENCE OF OXYGEN ON THE PRODUCTION OF HIGHER FULLERENES

In an attempt to increase the production yield of the higher fullerene s (C-76, C-78, C-84, etc.), Hf-, Zr- and Ti-doped electrodes were used in an are discharge process along with undoped electrodes for compari son. The soot was analysed by high-performance liquid chromatography. We found the following relations: (i) The yield of higher fullerenes i s anticorrelated with the yield of C60O and (ii) Hf, Zr and Ti doping reduces the C60O yield and accordingly increases the yield of higher f ullerenes. We suggest that the primary effect of the dopants is a redu ction of the oxygen partial pressure by the getter action of the coeva porated materials and, as a result, the higher fullerenes are formed m ore abundantly.