Controllable synthesis of single-, double- and triple-walled carbon nanotubes from asphalt

摘要

Single-, double- and triple-walled carbon nanotubes (SWNTs, DWNTs and TWNTs)have been controlla- bly synthesized by an arc discharge method using asphaltas carbon source. The morphology and struc- ture of three kinds of productssynthesized with Fe as catalyst were characterized by scanning electronmicroscopy (SEM), high-resolution transmission electron microscopy (HRTEM),Raman spectroscopy and energy dispersive X-ray spectroscopy (EDX). It was foundthat different buffer gases strongly affect the number layers in thesynthesized nanotubes. In the He gas atmosphere only SWNTs were found to besynthesized by arc discharge in contrast to the case in Ar gas atmosphere inwhich only TWNTs were formed. In N2 atmosphere both SWNTs and DWNTs weresynthesized. Our findings indicate that asphalt is a suitable industrial carbonsource for the growth of different type nanotubes.