Conditions of Simultaneous Growth and Separation of Single- and Multiwalled Carbon Nanotubes

In this paper we report conditions of the simultaneous, but separated, deposition of single- and multiwalled carbon nanotubes (SWCNTs, MWCNTs) in one and the same CVD process by a thermal decomposition of acetonitrile and ferrocene Lit different ratios. We have found an effective separation between SWCNTs and MWCNTs inside the reactor. The MWCNTs are formed on the hot reactor wall, whereas the SWCNTs are spontaneously originated in the gas phase. By means of an argon gas flow, they are transported through the quartz tube reactor and collected on a cooling finger. The morphology and purity of the pristine material are dependent on the amount of evaporated acetonitrile and C/Fe ratio in the gas phase. The reasons for the observed phenomena are discussed.