A New Method of Obtaining High Enrichment of Metallic Single-Walled Carbon Nanotubes

Arc-discharge with carbon electrodes containing Ni and Y2O3 in the presence of Fe(CO)5 vapors have been investigated. It is found that unlike the cathode deposit, the web deposited in the chamber contains mainly metallic single-walled carbon nanotubes (SWNTs) as evidenced from Raman and optical absorption spectroscopy. The percentage of metallic SWNTs increases with the concentration of Fe(CO)5. Under optimal conditions, the web contains over 90% of metallic SWNTs. This method enables the synthesis of nearly pure metallic SWNTs on a large scale.