Carbon nanostructures were synthesized by using a novel arc-discharge in the solution process. A multitude of defects on nanotubes and nanostructures was found. Evidence for these defects in as-synthesized C nanostructures was explored by using high-resolution transmission electron microscopy. Tri-, tetra-, penta-, hexa-, heptagonal, toroidal, oval, and spherical nanoshells were found in high-resolution transmission electron microscopy investigations, together with C nanotubes, C nanohorns, C rods, nanoporous C, dislodged graphene sheets, and amorphous C. Purification was carried out using 2 oxidation methods to eliminate the amorphous C. Several different defects caused by oxidation were also found in purified samples.

Defect Studies on As-Synthesized and Purified Carbon Nanostructures Produced by Arc-Discharge in Solution Process. D.Bera, J.P.Perrault, H.Heinrich, S.Seal: Journal of Nanoscience and Nanotechnology, 2006, 6[4], 1084-91