Fabrication and growth mechanism of carbon nanotubes by catalytic chemical vapor deposition

The synthesis of carbon nanotubes (CNTs) by chemical vapor deposition (CVD) of methane on catalyst of Ni–Cu–Al powder was reported. The influence factors on the growth morphology of CNTs, such as reaction time and different carrier gases concerning hydrogen, nitrogen as well as no carrier gas were investigated using SEM and TEM. The results showed that the reaction time brought no significant influence to the diameter of CNTs, but the average length of the CNTs was obviously increased with prolonging the reaction time. Relatively pure CNTs could be obtained with hydrogen as the carrier gas but with poor product rate compared with the CNTs with no carrier gas. Proper amount of CNTs with pure characteristic could be obtained with nitrogen as the carrier gas. Finally, a growth mechanism of section-seal is proposed for analyzing the growth process of general CNTs.