One-Step Synthesis of Metal-Encapsulated Carbon Nanotubes by Pulsed Arc Discharge in Water

Metal-encapsulated carbon nanotubes (MACNTs) have attracted considerable attention because of their numerous potential applications. However, there have been only a few reports on the encapsulation of CNTs with high boiling point metals. We investigated the encapsulation of CNTs with such metals by using a pulsed arc discharge method in water. When the melting points of the metals were higher than the sublimation temperature of carbon, the CNTs were encapsulated. In contrast, MACNTs could not be synthesized with lower melting point metals. The reason for this difference is attributed to the eutectic temperature of the alloys that are generated during precipitation of the carbon atoms.