Double-walled carbon nanotubes synthesized using carbon black as the dot carbonsource

Abstract

Double-walled carbon nanotubes (DWNTs) were synthesized used carbon black as the dotcarbon source by a semi-continuous hydrogen arc discharge process. High-resolutiontransmission electron microscopy (HRTEM) observations revealed that most of thetubes were DWNTs with outer and inner diameters in the range of 2.67–4 nm and1.96–3.21 nm, respectively. Most of the DWNTs were in a bundle form of about10–30 nm in diameter with high purity (about 70%) from thermal gravimetric analysis(TGA), resonant laser Raman spectroscopy, scanning electron microscopy (SEM)and TEM characterizations. It was found that carbon black as the dot carbonsource could be easy controlled to synthesize one type of nanotube. A simpleprocess combining oxidation and acid treatment to purify the DWNT bundles wasused without damaging the bundles. The structure of carbon black, as the keyelement for influencing purity, bundle formation and purification of DWNTs, isdiscussed.