Sulphur-free synthesis of helical carbon nanotubes

Abstract

Unique three-dimensional structure of helical carbon nanotubes renders them important in polymer composites, electrode materials of electrochemical devices and microwave absorbers. The most thoroughly studied synthetic method involves hydrocarbon pyrolysis in the presence of sulphur-containing compounds which provide coiling effect. However, sulphur compounds are toxic and are usually undesirable in the coils obtained. The present work describes a novel method for the synthesis of coiled nanotubes by the aerosol pyrolysis of ferrocene solution in methanol, which is easily scalable for high-quantity production and uses no sulphur. The results of systematic investigation of the synthetic procedure with the use of other metal nanoparticle precursors and oxygen sources as well as oxygen role are discussed in details.

Keywords:

• Carbon nanotubes
• Coils
• Catalytic pyrolysis
• Ferrocene
• Thermal analysis
• Raman spectroscopy
• Electron microscopy

Acknowledgements

The equipment for this study was provided under Moscow University Program of Development.