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

TL;DR

This study demonstrates the controllable synthesis of single-, double-, and triple-walled carbon nanotubes from asphalt using arc discharge, with the type of nanotube determined by the buffer gas atmosphere.

Contribution

It introduces a method to selectively produce different nanotube types from asphalt by adjusting the buffer gas during arc discharge.

Findings

He atmosphere yields only SWNTs

Ar atmosphere yields only TWNTs

N2 atmosphere yields SWNTs and DWNTs

Abstract

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