The influence of nitrogen sources on nitrogen doped multi-walled carbon nanotubes

Nxumalo, Edward N.; Letsoalo, Phatu Jack; Cele, Leskey M.; Coville, Neil J.

doi:10.1016/j.jorganchem.2010.08.030

Cited by 55 publications

(31 citation statements)

References 43 publications

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“…This is a new result; earlier studies using such a low N/C ratio of the reactants have focused on structural configurations of the N-MWCNTs. 26,32 Increasing the N/C ratio up to an order of magnitude suppressed the formation of pyrrolic nitrogen. Independent of the use of benzylamine or acetonitrile as the precursor, the outer layers of the N-MWCNTs synthesized at 800 1C contained mainly pyridinic nitrogen while the core stored N 2 gas.…”

Section: Discussionmentioning

confidence: 99%

“…Comparison of the amine and amide precursors for the N-MWCNTs growth showed that the N/C ratio in the feedstock material has a more noticeable effect on the morphology and nanotube yield than the actual nature of the nitrogen source. 26 The mechanism of CCVD growth of CNTs is not yet fully understood 27 and the question how the type of C-N bonding in the precursor may influence the forms of the incorporated nitrogen remains open. For nanotubes to form, the first step necessary in the synthesis process is the decomposition of a solid, liquid, or gaseous carbon-containing precursor, on a catalytic surface which can be a metal thin film or metal catalyst particles.…”

Section: Introductionmentioning

confidence: 99%

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Controlling pyridinic, pyrrolic, graphitic, and molecular nitrogen in multi-wall carbon nanotubes using precursors with different N/C ratios in aerosol assisted chemical vapor deposition

Bulusheva

Окотруб

Fedoseeva

et al. 2015

Phys. Chem. Chem. Phys.

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Nitrogen-containing multi-wall carbon nanotubes (N-MWCNTs) were synthesized using aerosol assisted chemical vapor deposition (CVD) techniques in conjunction with benzylamine:ferrocene or acetonitrile: ferrocene mixtures. Different amounts of toluene were added to these mixtures in order to change the N/C ratio of the feedstock. X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopy detected pyridinic, pyrrolic, graphitic, and molecular nitrogen forms in the N-MWCNT samples. Analysis of the spectral data indicated that whilst the nature of the nitrogen-containing precursor has little effect on the concentrations of the different forms of nitrogen in N-MWCNTs, the N/C ratio in the feedstock appeared to be the determining factor. When the N/C ratio was lower than ca. 0.01, all four forms existed in equal concentrations, for N/C ratios above 0.01, graphitic and molecular nitrogen were dominant. Furthermore, higher concentrations of pyridinic nitrogen in the outer shells and N 2 molecules in the core of the as-produced N-MWCNTs suggest that the precursors were decomposed into individual atoms, which interacted with the catalyst surface to form CN and NH species or in fact diffused through the bulk of the catalyst particles. These findings are important for a better understanding of possible growth mechanisms for heteroatom-containing carbon nanotubes (CNTs) and therefore paving the way for controlling the spatial distribution of foreign elements in the CNTs using CVD processes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Controlling pyridinic, pyrrolic, graphitic, and molecular nitrogen in multi-wall carbon nanotubes using precursors with different N/C ratios in aerosol assisted chemical vapor deposition

Bulusheva

Окотруб

Fedoseeva

et al. 2015

Phys. Chem. Chem. Phys.

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“…In-situ (during synthesis) or ex-situ (post-treatments) approaches are used to incorporate nitrogen onto the carbon structure [25]. Regarding post-treatments, the incorporation of nitrogen can be achieved either by treating the carbon materials with ammonia or using nitrogen-containing carbon precursors, such as urea, melamine, polyacrylonitriles, polyvinylpyridine, and quinoline-containing pitch [31,46,47]. Generally, the incorporation of pyridinic-like (N-6), pyrrolic-like (N-5), and graphitic-like (N-Q) structures enhances the basicity of the CNTs [10,11,48,49].…”

Section: Nitrogen-containing Surface Groupsmentioning

confidence: 99%

Tuning CNT Properties for Metal-Free Environmental Catalytic Applications

Rocha

Soares

Figueiredo

et al. 2016

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Abstract:The application of carbon nanotubes (CNTs) as metal-free catalysts is a novel approach for heterogeneous liquid phase catalytic systems. Textural and chemical modifications by liquid/gas phase or mechanical treatments, as well as solid state reactions, were successfully applied to obtain carbon nanotubes with different surface functionalities. Oxygen, nitrogen, and sulfur are the most common heteroatoms introduced on the carbon surface. This short-review highlights different routes used to develop metal-free carbon nanotube catalysts with enhanced properties for Advanced Oxidation Processes.

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“…Approximately 9.7 wt% nitrogen was determined by energy dispersive spectroscopy (Osváth et al 2009). Nxumalo et al (2010) studied the effect of varying the N-source concentration on the production of N-CNTs by a floating catalyst CVD method using a ferrocene/aniline/toluene solution. A ferrocene/aniline catalyst of 15 wt% produced N-CNTs with a small amount of by-products.…”

Section: Synthesis Of N-cntsmentioning

confidence: 99%

Nitrogen-doped carbon nanotubes as a metal catalyst support

et al. 2011

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The science and technology of catalysis is of fundamental importance to a national economy. Today about 90% of all technical chemicals are manufactured by the use of catalysts. Nanoparticles of noble metals are extremely important materials in the catalysis industry due to cost issues and properties that are not found in their bulk state. An efficient way to produce and stabilise noble metal nanoparticles is by dispersion on a suitable support. Carbon-based supports, such as carbon nanotubes, carbon spheres, carbon fibres, etc., have been found to be good supports for metal nanoparticles. However, to be used effectively, the carbon surface must be modified either by functionalisation or doping. This review discusses the synthesis and the possible applications of nitrogen-doped carbon nanotubes as supports for metal nanoparticles in heterogeneous catalysis.

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The influence of nitrogen sources on nitrogen doped multi-walled carbon nanotubes

Cited by 55 publications

References 43 publications

Controlling pyridinic, pyrrolic, graphitic, and molecular nitrogen in multi-wall carbon nanotubes using precursors with different N/C ratios in aerosol assisted chemical vapor deposition

Controlling pyridinic, pyrrolic, graphitic, and molecular nitrogen in multi-wall carbon nanotubes using precursors with different N/C ratios in aerosol assisted chemical vapor deposition

Tuning CNT Properties for Metal-Free Environmental Catalytic Applications

Nitrogen-doped carbon nanotubes as a metal catalyst support

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