Surface modification of multi-wall carbon nanotubes by nitrogen attachment

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Abstract

Commercial multiwall carbon nanotubes (MWCNT-s) were treated by RF activated N2 gas plasma at (nominally) room temperature. Treatment time of 5 to 10 min was applied at negative bias varying in the 0-300 V range. Surface chemical alterations were followed by X-ray photoelectron spectroscopy (XPS). All the applied treatments resulted in a significant build-up of nitrogen in the surface of MWCNT-s. The amount of nitrogen varied between 19 and 25 at.% depending on the treatment time and, in a lesser extent, also on biasing conditions. Interestingly, the nitrogen attachment was also significant (20 at.%) when the treatment commenced without bias. Evaluating the high-resolution N1s XP spectral region, typically three different chemical bonding states of the nitrogen was delineated. Peak component at 398.3 ± 0.3 eV is assigned to CNC type, at 399.7 ± 0.3 eV to sp2 N in melamine-type ring structure and at 400.9 ± 0.3 eV to N substituting carbon in a graphite-like environment. Identical chemical bonding of the nitrogen was detected on the surface of highly oriented pyrolytic graphite (HOPG) and on microcrystalline graphite surfaces treated in the same way for comparison. Estimating the penetration depth of the nitrogen atoms by the SRIM program it was concluded that at the applied DC bias energy range the implanted nitrogen is incorporated in the top 2-4 monoatomic layers of the samples. A model for the distribution of the chemically bonded nitrogen on the outer walls of the MWCNT-s is proposed.

Original languageEnglish
Pages (from-to)965-968
Number of pages4
JournalDiamond and Related Materials
Volume20
Issue number7
DOIs
Publication statusPublished - Jul 2011

Fingerprint

Carbon Nanotubes
attachment
Surface treatment
Carbon nanotubes
Nitrogen
carbon nanotubes
nitrogen
Graphite
graphite
melamine
Plasma Gases
pyrolytic graphite
ring structures
Melamine
nitrogen atoms
estimating
penetration
direct current
photoelectron spectroscopy
Carbon

Keywords

  • Carbon nanotube
  • Covalent N attachment
  • N bonding states
  • Plasma modification
  • XPS

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Electrical and Electronic Engineering
  • Mechanical Engineering
  • Physics and Astronomy(all)
  • Chemistry(all)

Cite this

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title = "Surface modification of multi-wall carbon nanotubes by nitrogen attachment",
abstract = "Commercial multiwall carbon nanotubes (MWCNT-s) were treated by RF activated N2 gas plasma at (nominally) room temperature. Treatment time of 5 to 10 min was applied at negative bias varying in the 0-300 V range. Surface chemical alterations were followed by X-ray photoelectron spectroscopy (XPS). All the applied treatments resulted in a significant build-up of nitrogen in the surface of MWCNT-s. The amount of nitrogen varied between 19 and 25 at.{\%} depending on the treatment time and, in a lesser extent, also on biasing conditions. Interestingly, the nitrogen attachment was also significant (20 at.{\%}) when the treatment commenced without bias. Evaluating the high-resolution N1s XP spectral region, typically three different chemical bonding states of the nitrogen was delineated. Peak component at 398.3 ± 0.3 eV is assigned to CNC type, at 399.7 ± 0.3 eV to sp2 N in melamine-type ring structure and at 400.9 ± 0.3 eV to N substituting carbon in a graphite-like environment. Identical chemical bonding of the nitrogen was detected on the surface of highly oriented pyrolytic graphite (HOPG) and on microcrystalline graphite surfaces treated in the same way for comparison. Estimating the penetration depth of the nitrogen atoms by the SRIM program it was concluded that at the applied DC bias energy range the implanted nitrogen is incorporated in the top 2-4 monoatomic layers of the samples. A model for the distribution of the chemically bonded nitrogen on the outer walls of the MWCNT-s is proposed.",
keywords = "Carbon nanotube, Covalent N attachment, N bonding states, Plasma modification, XPS",
author = "I. Bert{\'o}ti and I. Mohai and M. Mohai and J. Sz{\'e}pv{\"o}lgyi",
year = "2011",
month = "7",
doi = "10.1016/j.diamond.2011.05.011",
language = "English",
volume = "20",
pages = "965--968",
journal = "Diamond and Related Materials",
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AU - Bertóti, I.

AU - Mohai, I.

AU - Mohai, M.

AU - Szépvölgyi, J.

PY - 2011/7

Y1 - 2011/7

N2 - Commercial multiwall carbon nanotubes (MWCNT-s) were treated by RF activated N2 gas plasma at (nominally) room temperature. Treatment time of 5 to 10 min was applied at negative bias varying in the 0-300 V range. Surface chemical alterations were followed by X-ray photoelectron spectroscopy (XPS). All the applied treatments resulted in a significant build-up of nitrogen in the surface of MWCNT-s. The amount of nitrogen varied between 19 and 25 at.% depending on the treatment time and, in a lesser extent, also on biasing conditions. Interestingly, the nitrogen attachment was also significant (20 at.%) when the treatment commenced without bias. Evaluating the high-resolution N1s XP spectral region, typically three different chemical bonding states of the nitrogen was delineated. Peak component at 398.3 ± 0.3 eV is assigned to CNC type, at 399.7 ± 0.3 eV to sp2 N in melamine-type ring structure and at 400.9 ± 0.3 eV to N substituting carbon in a graphite-like environment. Identical chemical bonding of the nitrogen was detected on the surface of highly oriented pyrolytic graphite (HOPG) and on microcrystalline graphite surfaces treated in the same way for comparison. Estimating the penetration depth of the nitrogen atoms by the SRIM program it was concluded that at the applied DC bias energy range the implanted nitrogen is incorporated in the top 2-4 monoatomic layers of the samples. A model for the distribution of the chemically bonded nitrogen on the outer walls of the MWCNT-s is proposed.

AB - Commercial multiwall carbon nanotubes (MWCNT-s) were treated by RF activated N2 gas plasma at (nominally) room temperature. Treatment time of 5 to 10 min was applied at negative bias varying in the 0-300 V range. Surface chemical alterations were followed by X-ray photoelectron spectroscopy (XPS). All the applied treatments resulted in a significant build-up of nitrogen in the surface of MWCNT-s. The amount of nitrogen varied between 19 and 25 at.% depending on the treatment time and, in a lesser extent, also on biasing conditions. Interestingly, the nitrogen attachment was also significant (20 at.%) when the treatment commenced without bias. Evaluating the high-resolution N1s XP spectral region, typically three different chemical bonding states of the nitrogen was delineated. Peak component at 398.3 ± 0.3 eV is assigned to CNC type, at 399.7 ± 0.3 eV to sp2 N in melamine-type ring structure and at 400.9 ± 0.3 eV to N substituting carbon in a graphite-like environment. Identical chemical bonding of the nitrogen was detected on the surface of highly oriented pyrolytic graphite (HOPG) and on microcrystalline graphite surfaces treated in the same way for comparison. Estimating the penetration depth of the nitrogen atoms by the SRIM program it was concluded that at the applied DC bias energy range the implanted nitrogen is incorporated in the top 2-4 monoatomic layers of the samples. A model for the distribution of the chemically bonded nitrogen on the outer walls of the MWCNT-s is proposed.

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