Growth of branch carbon nanotubes on carbon nanotubes as support

A novel method combining the dense fluidized bed and the floating catalytically chemical vapor deposition method (FCCVD) to prepare carbon nanotubes (CNTs) was proposed. Propylene was decomposed at 660 °C, using the CNTs as supports and the metal particles from the in situ pyrolysis of ferrocene as catalyst. The conversion of propylene in this process was closed to 100% under an optimum condition. By SEM and TEM observations, the growth of new generation of CNTs was proven. It was demonstrated that the short and thin CNT branches exist on the tips or sidewalls of CNTs. Based on the analysis of the formation of catalytic sites in the FCCVD in a fluidized bed, a physical model of the formation of branches was proposed.