Microscopic mechanisms for the catalyst assisted growth of single-wall carbon nanotubes

Gavillet, Julie; Loiseau, A.; Ducastelle, F.; Thair, Saı̈d; Bernier, P.; Stéphan, Odile; Thibault, J.; Charlier, Jean‐Christophe

doi:10.1016/s0008-6223(02)00007-6

Cited by 123 publications

(107 citation statements)

References 45 publications

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“…So, there occurs segregation of the R S species from the core to the periphery of the grain of most, if not, all of these smaller nanoparticles, yielding many nanotubes from one single nanoparticle. This explains why Gavillet et al [43] obtained bundles of CNTs from one single, though relatively large, FECA nanoparticle.…”

Section: Communicationmentioning

confidence: 99%

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Thermodynamic Imbalance, Surface Energy, and Segregation Reveal the True Origin of Nanotube Synthesis

Mohammad¹

2012

Advanced Materials

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Extensive analyses of thermodynamic imbalance, surface energy, and segregation of nanotubes on nanoparticle surfaces are performed. A model for surface energy i developed. In addition, nanotube growth both by vapor-phase and solid-phase mechanisms is described. Segregation of the nanotube species to the periphery of the nanoparticle, the creation of an amorphous shell at this periphery, a droplet created in this shell, and the mediation of this droplet for supersaturation and nucleation of the nanotube species may be the true causes of nanotube growth.

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Section: Communicationmentioning

confidence: 99%

“…Gavillet et al [43] studied microscopic mechanisms for the Ni/ Yt-mediated [44] SWCNT growth. Based on energy dispersive x-ray (EDX) analysis, they confirmed that nanoparticles yielding SWCNTs were surrounded by amorphous shells, and that the seed materials responsible for SWCNT growth were embedded in these shells.…”

Section: Communicationmentioning

confidence: 99%

Thermodynamic Imbalance, Surface Energy, and Segregation Reveal the True Origin of Nanotube Synthesis

Mohammad¹

2012

Advanced Materials

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“…This is due to the fact that m-SWNTs, with their higher reactivity and fewer contributing chiralities, are easier to be suppressed and removed. [49] We note here that with the control of top Al 2 O 3 layer, the metallicity could be plausibly increased by over 200%. This observed high metallicity may have two possible contributions.…”

Section: Resultsmentioning

confidence: 68%

Controlled Growth of Single‐Walled Carbon Nanotube Networks by Catalyst Interfacial Diffusion

Yick

Han

Ostrikov

2014

Adv Materials Inter

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Single‐walled carbon nanotubes are promising for many applications due to their unique mechanical, electrical and optical properties. However, their application has been hampered so far by the lack of controllability in the direct growth process, in particular the size and chirality distributions which inevitably lead to a large variability of their electronic structures. Here we demonstrate the effect of catalyst interfacial diffusion using a tri‐layered Al2O3/Fe(Mo)/Al2O3 catalyst and achieve the effective control of density, diameter, and conductivity of the as‐grown nanotube networks. This method modulates the thickness of the top Al2O3 layer which affects the diffusion of Fe atoms and subsequently the formation of catalyst nanoparticles. We show that the tri‐layered catalyst allows one to vary the density of networks from 0.18 to 35 tubes/μm2, the diameter from 1.36 to 1.72 nm, and the metallic fraction from 20% to 45%. It may thus represent a promising strategy for tailoring the properties of as‐grown carbon nanotube networks for their proposed applications.

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“…This design was based on the assumption that the mechanism of carbon growth is a type of chemical vapor deposition (CVD), a Fibers 2016, 4, 9 6 of 14 mechanism associated with many forms of carbon growth from vapor phase hydrocarbons at elevated temperature [26,[30][31][32][33]41,42]. The CVD model assumes that carbon structures, including filaments, will grow on proper metal catalysts, particles, foils, etc., above the experimentally-determined breakdown temperature, generally between 500 and 1200˝C, of the organic precursor molecule, and that the process will continue until the hydrocarbon is fully depleted.…”

Section: Growth Experimentsmentioning

confidence: 99%

“…Specifically, in oxygen-free environments, carbon fibers and/or nanotubes grow via the catalytic decomposition of organic molecules. First, the molecule adsorbs on a metal particle catalyst surface; second, the molecule decomposes; and third, there is transport of carbon atoms driven by chemical potential gradients to a growing carbon filament/catalyst particle interface [30][31][32][33]. In contrast, the process occurring in oxygen-containing, fuel-rich, combustion environments is closer, chemically, to the production of soot.…”

Section: Introductionmentioning

confidence: 99%

Scaling up the Fabrication of Mechanically-Robust Carbon Nanofiber Foams

Arias‐Monje

Dominguez

Phillips

et al. 2016

Fibers

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Abstract:This work aimed to identify and address the main challenges associated with fabricating large samples of carbon foams composed of interwoven networks of carbon nanofibers. Solutions to two difficulties related with the process of fabricating carbon foams, maximum foam size and catalyst cost, were developed. First, a simple physical method was invented to scale-up the constrained formation of fibrous nanostructures process (CoFFiN) to fabricate relatively large foams. Specifically, a gas deflector system capable of maintaining conditions supportive of carbon nanofiber foam growth throughout a relatively large mold was developed. ANSYS CFX models were used to simulate the gas flow paths with and without deflectors; the data generated proved to be a very useful tool for the deflector design. Second, a simple method for selectively leaching the Pd catalyst material trapped in the foam during growth was successfully tested. Multiple techniques, including scanning electron microscopy, surface area measurements, and mechanical testing, were employed to characterize the foams generated in this study. All results confirmed that the larger foam samples preserve the basic characteristics: their interwoven nanofiber microstructure forms a low-density tridimensional solid with viscoelastic behavior. Fiber growth mechanisms are also discussed. Larger samples of mechanically-robust carbon nanofiber foams will enable the use of these materials as strain sensors, shock absorbers, selective absorbents for environmental remediation and electrodes for energy storage devices, among other applications.

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Microscopic mechanisms for the catalyst assisted growth of single-wall carbon nanotubes

Cited by 123 publications

References 45 publications

Thermodynamic Imbalance, Surface Energy, and Segregation Reveal the True Origin of Nanotube Synthesis

Thermodynamic Imbalance, Surface Energy, and Segregation Reveal the True Origin of Nanotube Synthesis

Controlled Growth of Single‐Walled Carbon Nanotube Networks by Catalyst Interfacial Diffusion

Scaling up the Fabrication of Mechanically-Robust Carbon Nanofiber Foams

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