Issue 44, 2017

The double-edged effects of annealing MgO underlayers on the efficient synthesis of single-wall carbon nanotube forests

Abstract

Recently, the millimetre-scale, highly efficient synthesis of single-wall carbon nanotube (SWCNT) forests from Fe catalysts has been reported through the annealing of the magnesia (MgO) underlayer. Here, we report the double-edged effects of underlayer annealing on the efficiency and structure of the SWCNT forest synthesis through a temperature-dependent examination. Our results showed that the efficiency of the SWCNT forests sharply increased with increased underlayer annealing temperatures from 600 °C up to 900 °C due to a temperature-dependent structural modification, characterized by increased grain size and reduced defects, of the MgO underlayer. Beyond this temperature, the SWCNT fraction also decreased as a result of further structural modification of the MgO underlayer. This exemplifies the double-edged effects of annealing. Specifically, for underlayer annealing below 600 °C, the catalyst subsurface diffusion was found to limit the growth efficiency, and for excessively high underlayer annealing temperatures (>900 °C), catalyst coalescence/ripening led to the formation of double-wall carbon nanotubes. As a result, three distinct regions of synthesis were observed: (i) a “low yield” region below a threshold temperature (∼600 °C); (ii) an “increased yield” region from 600 to 900 °C, and (iii) a “saturation” region above 900 °C. The efficient SWCNT forest synthesis could only occur within a specific annealing temperature window as a result of this double-edged effects of underlayer annealing.

Graphical abstract: The double-edged effects of annealing MgO underlayers on the efficient synthesis of single-wall carbon nanotube forests

Supplementary files

Article information

Article type
Paper
Submitted
31 Aug 2017
Accepted
18 Oct 2017
First published
19 Oct 2017

Nanoscale, 2017,9, 17617-17622

The double-edged effects of annealing MgO underlayers on the efficient synthesis of single-wall carbon nanotube forests

T. Tsuji, K. Hata, D. N. Futaba and S. Sakurai, Nanoscale, 2017, 9, 17617 DOI: 10.1039/C7NR06478K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements