PURIFICATION OF SINGLE-SHELL NANOTUBES

Communication: Purification of single-shell nanotubes is essential if reliable information about their physical and chemical properties is t o be obtained. Using the present synthetic techniques, samples typical ly contain 30% or more amorphous carbon and catalytic metal particle i mpurities. An extremely simple and efficient method of purification, i nvolving boiling the nanotubes in concentrated nitric acid, is reporte d. It is demonstrated that this method removes most of the impurities and, unlike some other methods, is not sensitive to the quality of the starting material.