SYNTHESIS OF CARBON NANOPARTICLES BY ARC DISCHARGE IN LIQUID NITROGEN USING METAL-GRAPHITE ELECTRODES

摘要

An idea of using pure iron and graphite electrodes for arc discharge in liquid nitrogen could be employed to synthesize carbon nanostructures, which are multiwalled carbon nanotubes (MWNT), carbon nanohorns (CNH), and carbon nanocapsules (CNC) containing metal cores. Effect of metallic cathode and discharge current on structure and yield of nanoparticles has been comprehensively investigated. Typical evidence of transmission electron microscopic images reveals that under some certain conditions of discharge in liquid nitrogen the synthesized products mainly consist of CNCs with mean diameter of 50-400 nm. Interestingly, CNHs with some MWNTs could also be obtained when conventional graphitic electrodes are employed. Meanwhile, MWNTs with diameter of 8-25 nm and length 150-250 nm became less selectively synthesized as cathode deposit under the condition of discharge in liquid nitrogen with higher arc current. Finally, it was found that the production yield of carbon nanoparticles synthesized by either carbon-carbon or carbon-iron electrodes became also lower with an increase in the arc current.