Carbon nanotubes based on anodic aluminum oxide nano-template Original Research Article

The effect of reaction gas and catalyst on the growth of carbon nanotubes (CNTs) in the anodic aluminum oxide (AAO) nano-template was investigated. A mechanism of CNT growth was proposed, which involves the competitive catalytic carbon deposition between on the Co catalyst particles electrodeposited at the bottom of the pores and on the AAO template itself. Presence of H2 in the reacting gas mixture significantly affected the morphology and the wall structure of synthesized CNTs: CNTs of high crystallinity grew out of pores with H2 while no CNTs overgrew in the absence of H2. CNT synthesis by CO disproportionation showed a lower growth rate and a higher degree of ordering than those grown by C2H2 pyrolysis. The unified mechanism of CNT growth on AAO template is also proposed.