The Transition from Amorphous Carbon to Carbon Nanohorns by DC Arc Discharge

Abstract

Amorphous carbon and carbon nanohorns had aroused an extensive concern due to their unique structure and wide application. It is worth noting that amorphous carbon nanoballs and carbon nanohorns can be obtained by a DC arc discharge. Remarkably, amorphous carbon nanoballs with the size of 20–80 nm were found in the air pressure of 40 kPa and a transition state of carbon nanostructures from amorphous carbon to carbon nanohorns was appeared with the increase of pressure. However, ‘dahlia-shaped’ carbon nanohorns with the size of 30–100 nm have been synthesized by a direct current (DC) arc discharge when the pressure of the buffer air is raised to 70 kPa. According to the above results, the growth mechanism of the transition from amorphous carbon to carbon nanohorns by a DC arc discharge was investigated. Namely, the species of buffer gas are key factors to the transition processes.