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High throughput production of single-wall carbon nanotube fibres independent of sulfur-source.

Accepted version
Peer-reviewed

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Type

Article

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Authors

Bulmer, John 
Gspann, Thurid 
Mizen, Jenifer 
Ryley, James 

Abstract

Floating catalyst chemical vapor deposition (FC-CVD) methods offer a highly scalable strategy for single-step synthesis and assembly of carbon nanotubes (CNTs) into macroscopic textiles. However, the non-uniform axial temperature profile of a typical reactor, and differing precursor breakdown temperatures, result in a broad distribution of catalyst particle sizes. Spun CNT fibres therefore contain nanotubes with varying diameters and wall numbers. Herein, we describe a general FC-CVD approach to obtain relatively large yields of predominantly single-wall CNT fibres, irrespective of the growth promoter (usually a sulfur compound). By increasing carrier gas (hydrogen) flow rate beyond a threshold whilst maintaining a constant C : H2 mole ratio, CNTs with narrower diameters, a high degree of graphitization (G : D ratio ∼100) and a large throughput are produced, provided S : Fe ratio is sufficiently low. Analysis of the intense Raman radial breathing modes and asymmetric G bands, and a shift in the main nanotube population from thermogravimetric data, show that with increasing flow rate, the fibres are enriched with small diameter, metallic CNTs. Transmission electron microscopy corraborates our primary observation from Raman spectroscopy that with high total flow rates, the fibres produced consist of predominantly small diameter SWCNTs.

Description

Keywords

40 Engineering, 4001 Aerospace Engineering, 4018 Nanotechnology, Nanotechnology, Bioengineering

Journal Title

Nanoscale

Conference Name

Journal ISSN

2040-3364
2040-3372

Volume Title

11

Publisher

Royal Society of Chemistry (RSC)

Rights

All rights reserved
Sponsorship
Engineering and Physical Sciences Research Council (EP/M02086X/1)
Engineering and Physical Sciences Research Council (EP/M015211/1)
Engineering and Physical Sciences Research Council (EP/L016567/1)
EPSRC (EP/M015211/1)