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 fullerenes using the DC carbon are evaporation of graphite. Fullerenes are found in the soot that condenses from the vapour phase, while nanotubes are located in the material that deposits on the cathode. This paper reports the discovery of a deposit on the anode, which is similar in appearance and composition to that formed on the cathode; i.e. it is a highly oriented graphitic material that contains nanotubes. Carbon isotope distribution studies indicate that the anode deposit, like the cathode deposit, is depleted in C-13, demonstrating that it is derived from small C-a(-) (n<3) species. Materials formed under He/N-2 atmospheres contain small amounts of nitrogen. This incorporation of nitrogen into carbon products provide further evidence for small precursor species 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.