Improved Diameter Control of Carbon Nanotubes Using Fe–V–O Nanoparticles as the Catalyst

Fe–O and Fe–V–O nanoparticles (NPs) containing 4.0, 8.1, 12.3, 16.4, and 20.6 at. % V were synthesized by a liquid phase process. Carbon nanotubes (CNTs) were grown from each NP using acetylene as the carbon source, in order to investigate the dependence of CNT diameter on V concentration. The results show that the diameters of the CNTs are larger than those of the NPs, but tend to approach that of the NP as V concentration increases. This suggests that the diameter control of CNTs can be improved by adding of V to Fe when Fe–O NPs are used as a catalyst of CNT growth.