The production of high purity carbon nanotubes with high yield using cobalt formate catalyst on carbon black

Carbon nanotubes (CNTs) were synthesized by catalytic chemical vapour deposition of acetylene diluted with nitrogen. Cobalt formate supported on carbon black was used as the catalyst. The synthesis was carried out at 700 °C in a quartz reactor for 30 min. Thermal analysis was used to determine the CNT yield. The purity of the nanotubes in the deposit was 96% and the yield was 1940% of the weight of the catalyst. Transmission electron microscopic images of as synthesized and oxidized nanotubes supported the thermogravimetric observations regarding the oxidation of CNT. The purity and the yield obtained are one of the highest reported.