We present the possibility of o-xylene as a carbon supplier for the synthesis of carbon nanotubes (CNTs) by the liquid-phase pulsed arc method using copper electrodes. Moreover, we investigate the effect of inrush current on the composition of the synthesized material. As inductance from an air-core coil increased, the weight ratio of copper particles tended to decrease dramatically. Moreover, with increasing inductance, the weight of the CNTs tended to increase. These results imply that control of discharge current is important for the synthesis of CNTs by the liquid-phase method.

We studied the one-step synthesis of carbon nanotubes (CNTs) containing metal by arc discharge in water, a technique by which we can synthesize CNTs using a simple device. In this study, we attempted to improve the rate of tungsten (W) inclusion by applying a pulsed arc discharge. By this technique, we found that the quantity of CNTs containing W increased compared with the results of using DC arc discharge. Furthermore, after investigating the effect of the correlation between pulse width and duty cycle on the rate of formation of CNTs containing W, it was determined that the maximum rate (30%) was achieved when the pulse width was 5 ms and the duty cycle was 50%.

Metal-encapsulated carbon nanotubes (M@CNTs) 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, M@CNTs 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.

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