Low temperature, non-isothermal growth of carbon nanotubes

Ting, Jyh‐Ming; Wu, Wan-Yu; Liao, Kuo–Fu; Wu, Hao-Hsuan

doi:10.1016/j.carbon.2009.05.023

Cited by 9 publications

(9 citation statements)

References 48 publications

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“…When the CNTs become longer, either the carbon source diffusion or catalyst decay was described, and this is highly dependent on the catalyst preparation and growth parameters. The possible rate-determining steps of CNT growth are hydrocarbon decomposition, [197,225,227] catalyst activity, [223,229] and diffusion of carbon into the catalyst particles. [198,224,230] Both the kinetic and the rate-determining step of CNT growth varies with different catalysts and growth parameters.…”

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Carbon Nanotube Mass Production: Principles and Processes

et al. 2011

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Our society requires new materials for a sustainable future, and carbon nanotubes (CNTs) are among the most important advanced materials. This Review describes the state-of-the-art of CNT synthesis, with a focus on their mass-production in industry. At the nanoscale, the production of CNTs involves the self-assembly of carbon atoms into a one-dimensional tubular structure. We describe how this synthesis can be achieved on the macroscopic scale in processes akin to the continuous tonne-scale mass production of chemical products in the modern chemical industry. Our overview includes discussions on processing methods for high-purity CNTs, and the handling of heat and mass transfer problems. Manufacturing strategies for agglomerated and aligned single-/multiwalled CNTs are used as examples of the engineering science of CNT production, which includes an understanding of their growth mechanism, agglomeration mechanism, reactor design, and process intensification. We aim to provide guidelines for the production and commercialization of CNTs. Although CNTs can now be produced on the tonne scale, knowledge of the growth mechanism at the atomic scale, the relationship between CNT structure and application, and scale-up of the production of CNTs with specific chirality are still inadequate. A multidisciplinary approach is a prerequisite for the sustainable development of the CNT industry.

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confidence: 99%

“…If the initial growth rate is proportional to the carbon source concentration and the rate-determining step is the carbon source decomposition, [197,225,227,228] the length of aligned CNTs can be expressed as:…”

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Carbon Nanotube Mass Production: Principles and Processes

et al. 2011

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“…For the growth of CNTs, a catalyst film is deposited on the substrate usually using a sputter deposition process. [30][31][32][33][34][35] The catalyst film would crack into particles prior to the growth of CNTs. In other words, the surface coverage by the catalyst is reduced.…”

Section: Introductionmentioning

confidence: 99%

Effects of Carbon Nanotube Grafting on the Performance of Electric Double Layer Capacitors

Chuang

Huang

Teng³

et al. 2010

Energy Fuels

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Carbon nanotubes (CNTs) were grown on polyacrylonitrile (PAN)-based activated carbon cloth (ACC) for use as electrodes in electric double layer capacitors. The catalyst used for the growth of CNTs was sputter-deposited Ni. It was found that the use of sputter-deposited catalyst for the growth CNTs prevents normally observed surface pore blockage on the ACC. The growth of CNTs took place in a thermal chemical vapor deposition chamber. During the CNT growth, ammonia was introduced into the growth chamber for enhancing the CNT growth and limiting the formation of pyrolytic carbon. The resulting CNTs were found to follows the tip growth mode, leading to direct contacts between the CNTs and the ACC fiber surfaces. Because of this and the high electrical conductivity of CNTs, the obtained CNTgrafted ACC electrodes exhibit significantly enhanced electrical conductivity and improved capacitance retention.

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“…The structure of these largediameter multiwalled CNTs tends to be highly disordered with many structural defects, including kinks, bends, wall breaks, and bamboo structures. [1][2][3][4][5][6] The advent of such structural disorder may result from the high growth rates of many of the CVD processes used; however, this is not known for certain. 7 We reported the growth of multiwalled CNTs with highly controlled diameters, ranging from 7 to 350 nm, using a thermal CVD process over a temperature range of 630-790 °C.…”

Section: Introductionmentioning

confidence: 99%

“…Although the CVD methods vary somewhat, ranging from high-vacuum, hot-filament, and microwave-assisted to simple ambient-pressure thermal processes, most reports result in multiwalled CNTs with diameters > 20 nm, compared with ≤ 3 nm for single-walled CNTs. The structure of these large-diameter multiwalled CNTs tends to be highly disordered with many structural defects, including kinks, bends, wall breaks, and bamboo structures. − The advent of such structural disorder may result from the high growth rates of many of the CVD processes used; however, this is not known for certain …”

Section: Introductionmentioning

confidence: 99%

Linear Behavior of Carbon Nanotube Diameters with Growth Temperature

et al. 2010

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High crystalline quality single-and multiwalled carbon nanotubes (CNTs) grow using thermal chemical vapor deposition (CVD) at temperatures ranging from 530 to 630 °C. Using identical Ni catalyst layers and a constant CO reduction annealing process at 600 °C, the number of walls in the resulting CNTs increases linearly from one to eight over this growth temperature range. The highest temperature used in the growth process appears to control the resulting inner core diameter, which is ∼1 nm for all CNTs grown e 610 °C, near the CO reduction anneal used for all the samples. The corresponding CNT outer diameters also increase linearly from 1 to 5 nm up to 610 °C. Using growth temperatures measurably higher than that of the reduction anneal results in both larger inner and outer diameters, inferring that the Ni catalyst islands grow with increasing temperature. These results suggest that independent control of the number of walls and the inner core diameter in CNTs is possible.

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Low temperature, non-isothermal growth of carbon nanotubes

Cited by 9 publications

References 48 publications

Carbon Nanotube Mass Production: Principles and Processes

Carbon Nanotube Mass Production: Principles and Processes

Effects of Carbon Nanotube Grafting on the Performance of Electric Double Layer Capacitors

Linear Behavior of Carbon Nanotube Diameters with Growth Temperature

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