A new type of carbon particle were produced by the CO2 laser ablation of carbon at room temperature without a metal catalyst. The product has a powder form of graphittic particles with a uniform size of about 80 nm. An individual particle is composed of an aggregate of many horn-shaped sheath of
S. Iijima, M. Yudasaka, R. Yamada, S. Bandow, K. Suenaga, F. Kokai, K. Takahashi, Nano-aggregates of single-walled graphitic carbon nano-horns. Chem. Phys. Lett., 309, 165 (1999).