Production of carbon nanotubes by single-pulse discharge in air

The production of carbon nanotubes (CNTs) has various methods, such as arc discharge, laser ablation, chemical vapor deposition (CVD), template-directed synthesis. These methods generally require, besides catalyst particles, vacuum environment and special ambient gas to prevent carbon from high temperature oxidation. However in this paper, CNTs were successfully produced on selected locations under atmospheric environment and room temperature by micro electrodischarge method. The micro electrodischarge system was composed with transistor circuit to offer discharging time of microseconds and peak current of several ampere. The effect of peak current and discharging time on the production of CNTs was addressed. Experimental results show that the structure and quantity of CNTs is different with different processing parameters. Multi-wall CNTs with the outer diameter of 17 nm and inner diameter of 5 nm were produced using peak current of 2.5 A and discharging time of 1000 μs.