CATALYTIC SYNTHESIS AND PURIFICATION OF CARBON NANOTUBES

Carbon deposition on a catalyst surface during decomposition of differ ent carbon-containing compounds can be used for the synthesis of carbo n nanotubes of graphitic structure. Different supported transition met al oxides were found to be active in the production of these nanotubes . The selectivity of the catalytic method is significantly higher than that of either the are discharge or the flame method. The experiments were carried out in a Row system, at 700 degrees C, with various acet ylene/nitrogen feeds. Deposited carbon was investigated by transition electron microscopy. The best samples were selected for further invest igation and for the synthesis of carbon nanotubes in large amounts. Fo r the purification, different methods were utilized. Separation of nan otubes from the catalyst (support and metal particles) and from other carbon products (soot, fibres) can be carried out only by the combinat ion of ultrasound and various chemical treatments.