High Yield Preparation of Carbon Nanotube Arrays of Good Quality by CVD

Multi-walled carbon nanotube arrays (CNTAs) of good quality are prepared in a high yield of similar to 7?wt.% by CVD at 850?degrees C, using rectified cyclohexane as the carbon source. All the CNTAs forming on the inner wall of a quartz tube reactor are of good quality, but those forming in the zone 4060?cm away from the entrance of the furnace show the best degrees of graphitization and alignment. The length of these CNTAs is similar to 200?mu m, their average growth rate during the CVD reaction (8 min) is 25?mu m min-1, and the content of MWCNTs and iron are 93.7?wt.% and 3.9?wt.%, respectively. The effect of CVD reaction temperature on the yield and quality of the CNTAs is also investigated and explained by knowledge of the chemical kinetics of reaction; four main chemical reactions are suggested for the growth of CNTAs during the process of CVD reaction, and the ratios of the active carbon species (A) to the active Fe catalyst species (C) (A:C) and the other carbon species (B) (A:B). The reasons for the high yield of CNTAs of good quality are discussed briefly.