THE ANODE DEPOSIT FORMED DURING THE CARBON-ARC EVAPORATION OF GRAPHITE FOR THE SYNTHESIS OF FULLERENES AND CARBON NANOTUBES

A number of different products are formed in the synthesis of fulleren es using the DC carbon are evaporation of graphite. Fullerenes are fou nd in the soot that condenses from the vapour phase, while nanotubes a re located in the material that deposits on the cathode. This paper re ports the discovery of a deposit on the anode, which is similar in app earance and composition to that formed on the cathode; i.e. it is a hi ghly oriented graphitic material that contains nanotubes. Carbon isoto pe distribution studies indicate that the anode deposit, like the cath ode deposit, is depleted in C-13, demonstrating that it is derived fro m small C-a(-) (n<3) species. Materials formed under He/N-2 atmosphere s contain small amounts of nitrogen. This incorporation of nitrogen in to carbon products provide further evidence for small precursor specie s to these materials. The combustion properties of the nitrogen-doped materials were quite different to those of the undoped materials. The results are discussed in terms of mechanisms for the formation of the products of the carbon are evaporation process.