Influence of the operating conditions on the production rate of multi-walled carbon nanotubes in a CVD reactor

Gommes, Cédric; Blacher, Silvia; Bossuot, Christophe; Marchot, Pierre; Nagy, J.B.; Pirard, Jean‐Paul

doi:10.1016/j.carbon.2004.01.063

Cited by 46 publications

(21 citation statements)

References 11 publications

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“…They report a kinetic law with a positive order with respect to ethylene concentration and a process limitation due to internal diffusion in the porosity of catalyst grains. Furthermore, the works of Gommes et al 10 and Pirard et al 8 concern a kinetic study on MWCNT formation from ethylene mixed with hydrogen or helium using Fe-Co/Al 2 O 3 catalysts. They connected a mass spectrometer to their horizontal fixed bed reactor (quartz boat).…”

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confidence: 99%

Kinetic study of carbon nanotubes synthesis by fluidized bed chemical vapor deposition

et al. 2008

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in Wiley InterScience (www.interscience.wiley.com).Multi-walled carbon nanotubes (MWCNTs) have been produced with high selectivity by fluidized bed catalytic chemical vapor deposition from ethylene on Fe/Al 2 O 3 catalysts. The influence of operating parameters such as deposition duration, temperature, ethylene and hydrogen partial pressures, and iron loading on MWCNT productivity, process selectivity, characteristics of final powders, and chemical composition of the outlet gases has been analyzed. Using gas phase chromatography, methane and ethane have been detected, whatever are the conditions used. Between 650 and 7508C, no catalyst deactivation occurs because nucleation remains active all along the synthesis, thanks to the explosion of the catalyst grains. Above 6508C, ethane itself produces MWCNTs, whereas methane does not react in the temperature range, 550-7508C. The formation of MWCNTs induces marked bed expansions and sharp decreases of grain density. Apparent kinetic laws have been deduced from the collected data. The apparent partial orders of reaction for ethylene, hydrogen, and iron were found to be 0.75, 0, and 0.28, respectively.

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Kinetic study of carbon nanotubes synthesis by fluidized bed chemical vapor deposition

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“…The 0.5 g catalyst bed was 10 mm in width and 200 mm in length. Under these conditions, the reactor works in chemical regime [16]. After purging the reactor with 2.23 mmol s À1 of helium for 10 min, the reaction was carried out at 700 8C for 15 min in a mixture of 0.223 mmol s À1 of C 2 H 4 and 0.521 mmol s À1 of He.…”

Section: Carbon Nanotubes Synthesismentioning

confidence: 99%

Carbon nanotubes synthesis by the ethylene chemical catalytic vapour deposition (CCVD) process on Fe, Co, and Fe–Co/Al2O3 sol–gel catalysts

Kim

Heinrichs

Colomer

et al. 2007

Applied Catalysis A: General

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The production of carbon nanotubes by the chemical catalytic vapour deposition, CCVD, process was examined over iron, cobalt, and a mixture of iron and cobalt supported on alumina catalysts synthesized by a one step sol-gel process. The catalysts were synthesized from several metal precursors, iron nitrate, cobalt and iron acetylacetonate, and cobalt acetate. Ethylene was used as the carbon source.The Co/Al 2 O 3 catalysts showed better activity and selectivity in carbon nanotubes synthesis than Fe/Al 2 O 3 and Fe-Co/Al 2 O 3 catalysts. The carbon deposit was found by TEM analysis to be rich in carbon nanotubes in the case of Co/Al 2 O 3 but to be very poor in the case of the Fe-Co/ Al 2 O 3 catalysts. The catalysts were characterized by TEM, XRD, and nitrogen adsorption. It was shown that iron and cobalt are in oxide form. Metal-support interactions and metal oxide particle size are influenced by the nature of the precursor and this nature is an important factor for the activity and selectivity of the catalysts. Moreover, a correlation has been found between the metal oxide particle sizes, the diameter of the carbon nanotubes, and the catalytic activity. #

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“…They obtained CNT production rates in agreement with their experimental data. Gommes et al 5 performed a kinetic study of CNT synthesis from ethylene and Fe x -Co y supported on alumina catalysts put in a small boat at the center of an empty quartz tube. By considering a unique first-order heterogeneous reaction, they developed 1D simple models of the gas behavior, either in purely axial convective conditions in the reactor, or in purely vertical diffusive conditions through the catalytic bed.…”

Section: Introductionmentioning

confidence: 99%

Kinetic modeling study of carbon nanotubes synthesis by fluidized bed chemical vapor deposition

Philippe¹,

Serp²,

Kalck³

et al. 2008

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com).The kinetic and physical laws developed in the first part of the study have been implemented in a modified version of the bubbling bed Kato and Wen model to represent multiwalled carbon nanotubes (MWCNTs) synthesis by catalytic chemical vapor deposition from ethylene as carbon source and using an Fe/Al 2 O 3 catalyst. The absolute deviation for MWCNT productivity between experimental results of Part 1 and simulations is of 17.3% when only considering experiments for which the bed is mainly in bubbling regime. The influence of the main operating parameters on the evolutions with time of the species molar fractions, the weight of MWCNTs formed, and the bed characteristics has been numerically studied. Such capabilities can help designing new reactors. Finally, the model has been used for scale up purposes, by increasing the reactor diameter and catalyst weight. Simulations have shown that the process productivity could reach 74 tons/year of MWCNTs in a reactor 45 cm in diameter. 2008 American Institute of Chemical Engineers AIChE J, 55: [465][466][467][468][469][470][471][472][473][474] 2009

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Influence of the operating conditions on the production rate of multi-walled carbon nanotubes in a CVD reactor

Cited by 46 publications

References 11 publications

Kinetic study of carbon nanotubes synthesis by fluidized bed chemical vapor deposition

Kinetic study of carbon nanotubes synthesis by fluidized bed chemical vapor deposition

Carbon nanotubes synthesis by the ethylene chemical catalytic vapour deposition (CCVD) process on Fe, Co, and Fe–Co/Al2O3 sol–gel catalysts

Kinetic modeling study of carbon nanotubes synthesis by fluidized bed chemical vapor deposition

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