Influence of the Catalyst Hydrogen Pretreatment on the Growth of Vertically Aligned Nitrogen-Doped Carbon Nanotubes

Abstract

Thin vertically aligned N-doped nanotubes with narrow layered nanotube diameter distribution and a defined doping level have been synthesized by chemical vapor deposition. Multilayered catalysts and a pure acetonitrile C/N feedstock have been employed. The observed nitrogen content was up to 6% with a predominant sp2 bonding configuration in relation to other nitrogen incorporated forms. Depending on the process parameters, we were able to tune the nitrogen content and the formation ratio of small nanotubes to bamboo nanotubes. The use of multilayer catalyst allows a large temperature window in which substitutionally doped structures form in comparison to other catalysts.

Changes of the electronic structure of the atoms of nitrogen in nitrogen-doped multiwalled carbon nanotubes under the influence of pulsed ion radiation

“…2b), the N 1s spectrum can be deconvoluted into five components: N1, N2, N3, N4, N5. Spectrum component N1 at the binding energy 398.7 ± 0.2 eV corresponds to nitrogen in the pyridinic configuration [2,[5][6][7]9]. In pyridine-like defects of the graphene structure of the nanotubes two electrons of nitrogen are involved in r-bonds with neighboring carbon atoms, one electron contributes to the p-system of CN x -MWCNTs, and two electrons form a pair localized around the nitrogen atom.…”

“…Peak N3, localized at the energy 401.5 ± 0.2 eV, corresponds to the three-coordinated nitrogen atoms which substitute carbon atoms in the layers of CN x -MWCNTs (substituting/graphitic nitrogen) [5][6][7]25,26]. This configuration of nitrogen increases the conductivity of CN x -MWCNTs due to the additional nitrogen electron which fills the free p ⁄ -states of the conduction band of the nanotubes.…”

“…Doping of CNTs with nitrogen atoms [3,4] is one of the ways to operate their electrical properties. It is known that nitrogen in N-doped multiwalled carbon nanotubes (CN x -MWCNTs) is in a variety of configurations, such as graphitic, pyridinic, pyrrolic, as well as in the form of groups NO and molecular N 2 [2,[5][6][7]. Quantitative nitrogen content in these chemical states has different effects on the electronic structure CN x -MWCNTs.…”

Carbon nanotube diameter tuning using hydrogen amount and temperature on SiO2/Si substrates

“…At higher temperatures surface roughness increases due to de-oxidation of the surface [27] or due to thermal expansion coefficient mismatch between the layers [28]. It is generally accepted that there is a strong correlation between the size of the catalyst particle and CNT diameter [29,30]; however, it is still under debate what controls the size of the catalyst particles when thin film catalyst is used to synthesize nanotubes.…”

Can Commonly Used Hydrazine Produce n‐Type Graphene?

“…www.chemeurj.org disorder of the GO structure after introduction of N atoms into the rGO layers, the sharp peak in the C1s spectrum of the N-doped rGO sample, which is still assigned to the C À C bond of sp 3 carbon atoms, shifts to a higher binding energy of 284.6 eV. [47] The new peak was obtained at 285.7 eV by peak fitting, suggesting the bonding formation of doped nitrogen atoms was sp 3 carbon atoms (Figure 1 c). [48] The hydrazine treatment followed by RTA resulted in a significant restoration of sp 2 carbon sites, but was still unable to completely remove all oxygen functional groups (Figure 1 a).…”