Continuous production of carbon nanotubes and diamond films by swirled floating catalyst chemical vapour deposition method

A.S Afolabi,S.E Iyuke,H.C Van Zyl Pienaar,A.S Abdulkareem

doi:10.4102/sajs.v105i7/8.71

Abstract

Various techniques for the synthesis of carbon nanotubes (CNTs) are being developed to meet an increasing demand as a result of their versatile applications. Swirled floating catalyst chemical vapour deposition (SFCCVD) is one of these techniques. This method was used to synthesise CNTs on a continuous basis using acetylene gas as a carbon source, ferrocene dissolved in xylene as a catalyst precursor, and both hydrogen and argon as carrier gases. Transmission electron microscopy analyses revealed that a mixture of single and multi-wall carbon nanotubes and other carbon nanomaterials were produced within the pyrolytic temperature range of 900–1 100°C and acetylene flow rate range of 118–370 ml min –1 . Image comparison of raw and purified products showed that low contents of iron particles and amorphous carbon were contained in the synthesised carbon nanotubes. Diamond films were produced at high ferrocene concentration, hydrogen flow rate and pyrolysis temperatures, while carbon nanoballs were formed and attached to the surface of the CNTs at low ferrocene content and low pyrolysis temperature. : SFCCVD, CNTs, continuous production, pyrolysis, diamond films

Highlights

Carbon nanotubes (CNTs) are poised to make themselves the ‘materials of the millennium’ due to their unique characteristics, such as good mechanical properties[1,2] good electrical conductivity[3,4,5] and other special functional properties,[6,7] which have culminated in various technological developments in recent times
The swirled floating catalyst chemical vapour deposition (SFCCVD) method was used to synthesise various carbon nanomaterials at different flow rates of the carbon source and carrier gas, and different catalyst concentrations
Transmission electron microscopy images of (a) as-synthesised and (b) purified multi-walled carbon nanotubes (MWCNTs) temperature of 1 100°C and an acetylene flow rate obtained at 3% ferrocene and 1 000°C

Summary

Introduction

Carbon nanotubes (CNTs) are poised to make themselves the ‘materials of the millennium’ due to their unique characteristics, such as good mechanical properties[1,2] good electrical conductivity[3,4,5] and other special functional properties,[6,7] which have culminated in various technological developments in recent times. Some of the applications of these materials are energy storage,[9] hydrogen storage,[10,11,12] field emission,[13] nanoelectric devices,[14] artificial muscle,[15] reinforcing materials[16] and catalyst support in fuel cells.[17,18] This versatility in the applications of CNTs places their price in the international market as high as five hundred U.S dollars per gram.

Methods

Results

Conclusion