Prediction of carbon nanotube growth success by the analysis of carbon–catalyst binary phase diagrams

Deck, Christian P.; Vecchio, Kenneth S.

doi:10.1016/j.carbon.2005.07.023

Cited by 251 publications

(163 citation statements)

References 35 publications

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“…The variation in the structures and the formation efficiency were similar to those catalyst metals such as Fe and Co which were accepted as good catalyst for CNT/CNF growth previously (11). Although there was not a detailed investigation on Zn as a catalyst material for the production of nanostructured carbon materials, it was accepted as a poor catalyst since some undesired carbon by-products were observed (23). However, the Zn based catalysts prepared in this study appeared to be very active towards the production of CNT/CNFs with uniform and narrow diameter distribution.…”

Section: Resultssupporting

confidence: 55%

Carbon Nanotube and Nanofiber Growth on Zn-Based Catalysts

Dumanlı

Yürüm

2011

Fullerenes, Nanotubes and Carbon Nanostructures

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In this study, acetylene gas was delivered to a catalyst network consists of NaCl-support and Zn nanoparticles in a temperature range of 500-700°C by means of a chemical vapor deposition (CVD). A principle feature that delineated this CVD study from prior studies lay, first in the method used to support the catalyst and secondly the choice of the catalyst metal. In particular, NaCl was deliberately retained and exploited in subsequent manipulations for the reason that it performed remarkably well as a support medium. The catalytic activity of Zn towards production of CNT/CNFs appeared to be promoted as a result of using molten ionic substrate.

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Section: Resultssupporting

confidence: 55%

Carbon Nanotube and Nanofiber Growth on Zn-Based Catalysts

Dumanlı

Yürüm

2011

Fullerenes, Nanotubes and Carbon Nanostructures

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“…Up to now, this ␥-Fe phase was observed in small iron precipitates embedded in a Cu matrix, 38 in FeCu mechanically alloyed compounds, 39,40 in the synthesis of carbon nanotubes, [41][42][43][44][45][46][47][48] or in Fe-NPs and thin films but confined down to a few monolayers of thickness. [49][50][51][52][53][54][55] The magnetism of ␥-Fe phase depends strongly on the Fe-Fe interatomic distances 56 although both the morphology of the sample and the particle size could play an important role.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and magnetism of nanoparticles withγ-Fecore surrounded byα-Feand iron oxide shells

et al. 2010

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Iron-carbon nanocomposites have been elaborated by means of a simple chemical procedure based on in situ synthesis of iron nanoparticles within the nanopores of an activated carbon. The Fe nanoparticles present a broad particle-size distribution ͑5-40 nm͒. A combined structural and magnetic study seems to suggest that most of the nanoparticles of mean size ϳ15 nm have exotic "onionlike" core-shell morphology of ␥-Fe nucleus surrounded by a concentric double shell of ␣-Fe and maghemitelike oxide. The true nature of Fe-oxide was successfully evidenced through room temperature x-ray absorption spectroscopy. The whole system does not reach a fully superparamagnetic regime even at 750 K, probably due to higher blocking temperatures for the largest nanoparticles. Mössbauer spectrometry indicates that low temperature para-to-antiferromagnetic transition for the ␥-Fe phase cannot be discarded. In addition, the external Fe-oxide shell exhibits spin-glass behavior giving rise to the freezing of its magnetic moments at low temperatures. Hence, we propose a competing double magnetic coupling: ͑i͒ the oxide shell/␣-Fe interaction and ͑ii͒ the possible antiferromagnetic coupling between ␥-Fe nucleus and ␣-Fe layer; as being both responsible for the observed exchange bias effect at T =5 K ͑H ex Ϸ 150 Oe͒.

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“…One reason could be that inner transition elements are not known to be highly catalytic as the transition elements. It has also been suggested that lanthanoids such as gadolinium and europium exhibit insufficient carbon solubility, slow carbon diffusion, and limited carbide formation to catalyze CNT growth [8]. Recently, gadolinium and europium were used…”

mentioning

confidence: 99%

Towards the low temperature growth of uniform diameter multi walled carbon nanotubes by catalytic chemical vapour deposition technique

Somanathan

Pandurangan

2010

Nano-Micro Lett

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Mesoporous MCM-41 molecular sieves containing f-block transition elements (gadolinium) with various Si/Gd ratios (50, 75 and 100) were synthesised by a hydrothermal method. Their mesoporous structure was confirmed by X-ray diffraction, nitrogen sorption studies, thermogravimetric analysis, scanning and transmission electron microscopy. The local environment of Gd in the material was studied by electron paramagnetic resonance. The compatibility of the catalyst for the synthesis of uniform diameter CNTs by varying the temperature from 400 to 650°C with fixed flow rates of N 2 and C 2 H 2 (140 ml/min and 40 ml/min, respectively). The product is mostly metal containing thin MWCNTs with diameter of 10a20 nm. Characterisation shows that a combination of Gd-MCM-41 (100) catalyst gives a high yield of high quality MWCNTs under optimum growth conditions. [7]. The major drawback of arc discharge and laser evaporation methods is that they are extremely uncontrolled in terms of process parameters, resulting in CNTs that contains significant fractions of unwanted material and that are difficult to manipulate and assemble in specific designs. CVD method is based on the thermal decomposition of hydrocarbon compounds over transition metal catalyst particles.It appears to be a simple and economic technique to synthesize this kind of material at a low temperature, ambient pressure and it represents the best hope for large scale production.To date, all the metal-catalyzed CNT growth studies have mainly focused on transition metals. Curiously, f-block transition elements also referred to as inner transition elements have still not been well explored. One reason could be that inner transition elements are not known to be highly catalytic as the transition elements. It has also been suggested that lanthanoids such as gadolinium and europium exhibit insufficient carbon solubility, slow carbon diffusion, and limited carbide formation to catalyze CNT growth [8]. Recently, gadolinium and europium were used

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Prediction of carbon nanotube growth success by the analysis of carbon–catalyst binary phase diagrams

Cited by 251 publications

References 35 publications

Carbon Nanotube and Nanofiber Growth on Zn-Based Catalysts

Carbon Nanotube and Nanofiber Growth on Zn-Based Catalysts

Microstructure and magnetism of nanoparticles withγ-Fecore surrounded byα-Feand iron oxide shells

Towards the low temperature growth of uniform diameter multi walled carbon nanotubes by catalytic chemical vapour deposition technique

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