Onion-like graphitic particles observed in wood charcoal

Abstract

Onion-like graphitic particles were first observed by Iijima in ark-discharge-deposited carbon blacks. 1 When the microstructure of the carbon blacks produced by vacuum evaporation of graphite was studied, onion-like structures were found by high-resolution electron microscopy. These structures were also found by Ugarte after irradiating carbon soot with high-energy (300kV) electron beams for a prolonged period. 2 Other techniques have also been reported to produce similar structures from other substances. 3 Although onion-like graphitic particles are now a well-defined allotropic nanophase of carbon, 4 they have not been found in wood charcoal thus far. This report describes their growth during evolution in wood charcoal. The microstructure of carbonized microfibrils, which were observed in regions close to the groups of onion-like graphitic particles, are also presented in this paper. Materials and methods