Improved oxidation resistance of single-walled carbon nanotubes produced by arc discharge in a bowl-like cathode

We report an improvement in oxidation resistance of single-walled carbon nanotubes (SWNTs) produced by arc discharge in a bowl-like cathode. The Raman spectrum of the new arc-discharge SWNTs shows a significant enhancement in the G/D (similar to1590:similar to1350 cm(-1)) ratio, suggesting that cleaner and less defective SWNTs are generated by the new arc-discharge method compared to the conventional arc-discharge method. These changes are further confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Production of improved SWNTs with better oxidation resistance is mainly ascribed to the in-situ annealing effect of the bowl-like cathode.