Parametric study of carbon nanotube growth via cobalt-catalyzed ethanol decomposition

Ethanol has been found to be a superior carbon source that can produce clean carbon nanotubes with minimal amorphous carbon impurity. In this study we have investigated the influence of several synthesis parameters on the growth of carbon nanotubes via cobalt-catalyzed decomposition of ethanol on porous alumina substrates. The synthesis parameters investigated here include the synthesis temperature and time, the flow rate of carrier gas for ethanol, and the concentration of cobalt catalyst solution. Our results suggest that there exist a critical flow rate for ethanol carrier gas and a critical concentration of cobalt solution, below which no carbon nanotube can grow. There also exist optimum parametric windows for synthesis temperature and cobalt solution, within which clean carbon nanotubes grow readily. © 2005 Elsevier B.V. All rights reserved.