Synthesis of Carbon Nanomaterials by Atmospheric Pressure Microdischarge

Abstract

Atmospheric pressure microdischarge of CH4 was generated in a removable gas cell fitted in a scanning electron microscope (SEM) for synthesizing carbon nanomaterials.
A Pd alloy needle with 12μm tip curve radius and a polycrystalline Pt film with 600nm thickness were used as the anode and
the cathode respectively. Apulse voltage was applied. The pressure of CH4 was 100 kPa. The gaps between the anode and the cathode were changed from 5μm to 100μm. The field emission scanning electron
microscope (FESEM) and the energy dispersive X-ray spectrometer (EDX) results showed that spherical or sticklike carbon nanomaterials
were fabricated in the discharge area on the surface of the Pt film cathode after the microdischarge. With the time of microdischarge
increase, the spherical carbon nanomaterials grew into the sticklike gradually within 7s. For 7s deposition, the length
and the diameter of some sticklike carbon nanomaterials were 1000nm and 20nm respectively. However, when the deposition
time was longer than 8s, the discharge center was melted. Ahigh resolution transmission electron microscope (HRTEM) was
also used to characterize the structures of the sticklike carbon nanomaterials, which showed that the sticklike carbon nanomaterials
were nanorods. This microdischarge is a fast and simple method for synthesizing carbon nanomaterial.