An experimental and theoretical examination of the effect of sulfur on the pyrolytically grown carbon nanotubes from sucrose-based solid state precursors
Author
Kucukayan, G.
Ovali, R.
Ilday, S.
Baykal, B.
Yurdakul, H.
Turan, S.
Gulseren, O.
Bengu, E.
Date
2011Source Title
Carbon
Print ISSN
0008-6223
Electronic ISSN
1873-3891
Publisher
Elsevier
Volume
49
Issue
2
Pages
508 - 517
Language
English
Type
ArticleItem Usage Stats
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Abstract
Multi-walled carbon nanotubes (MWCNTs) were synthesized through pyrolysis of the sulfuric acid-carbonized byproduct of sucrose. While the presence of sulfur in the reaction
media has a key role in the formation and population density of MWCNTs, we have not
observed the formation of Y-junctions or encountered other novel carbon nanotube formations. Results indicate the presence of sulfur in catalyst particles trapped inside nanotubes,
but failed to find sulfur in the side-walls of the CNTs. In order to verify and explain these
findings, we analyzed the behavior of sulfur and its possible effects on the side-wall structure of CNTs by using density functional theory-based calculations on various atomic models depicting sulfur inclusion in the side-walls. The results of the computational study were
in line with the experimental results and also provided a new perspective by suggesting
that the defects such as pentagons may act as nucleation sites for the Y-branches. The
results indicated that sulfur prefers to adsorb on these defective regions, but it is not
responsible for the formation of these structures or defects.