Harvesting of large, substrate-free sheets of vertically aligned multiwall carbon nanotube arrays

Craddock, John D.; Weisenberger, Matthew C.

doi:10.1016/j.carbon.2014.09.039

Cited by 7 publications

(4 citation statements)

References 10 publications

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“…Multi-walled carbon nanotubes were produced via the CVD of a xylene/ferrocene feedstock between 750 and 850 °C on quartz substrates [30,31]. The AC employed was Darco KB-G obtained from Sigma Aldrich (St. Louis, MO, USA).…”

Section: Catalyst Synthesismentioning

confidence: 99%

Activated Carbon, Carbon Nanofiber and Carbon Nanotube Supported Molybdenum Carbide Catalysts for the Hydrodeoxygenation of Guaiacol

et al. 2015

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Abstract:Molybdenum carbide was supported on three types of carbon support-activated carbon; multi-walled carbon nanotubes; and carbon nanofibers-using ammonium molybdate and molybdic acid as Mo precursors. The use of activated carbon as support afforded an X-ray amorphous Mo phase, whereas crystalline molybdenum carbide phases were obtained on carbon nanofibers and, in some cases, on carbon nanotubes. When the resulting catalysts were tested in the hydrodeoxygenation (HDO) of guaiacol in dodecane, catechol and phenol were obtained as the main products, although in some instances significant amounts of cyclohexane were produced. The observation of catechol in all reaction mixtures suggests that guaiacol was converted into phenol via sequential demethylation and HDO, although the simultaneous occurrence of a direct demethoxylation pathway cannot be discounted. Catalysts based on carbon nanofibers generally afforded the highest yields of phenol; notably, the only crystalline phase detected in these samples was Mo2C or Mo2C-ζ, suggesting that crystalline Mo2C is particularly selective to phenol. At 350 °C, carbon nanofiber supported Mo2C afforded near quantitative guaiacol conversion, the selectivity to phenol approaching 50%. When guaiacol HDO was performed in the presence of acetic acid and furfural, guaiacol conversion decreased, although the selectivity to both catechol and phenol was increased. OPEN ACCESSCatalysts 2015, 5 425

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Section: Catalyst Synthesismentioning

confidence: 99%

Activated Carbon, Carbon Nanofiber and Carbon Nanotube Supported Molybdenum Carbide Catalysts for the Hydrodeoxygenation of Guaiacol

et al. 2015

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“…CNT synthesis has been a subject of interest in research labs around the world for multiple decades, and much has been learned, especially when it comes to chemical vapor deposition (CVD) [12][13][14][15]. CVD synthesis of CNTs began with directed growth on substrates but has since evolved to include floating-catalyst growth that is substrate-free, especially as it comes to more commercial-scale production [16,17] utilizing a larger reaction volume. In addition, to process control and cost considerations, there is also a need to adopt greener and environment friendly synthesis methods utilizing natural, renewable, cheaper waste materials [18].…”

Section: Introductionmentioning

confidence: 99%

From Newspaper Substrate to Nanotubes—Analysis of Carbonized Soot Grown on Kaolin Sized Newsprint

Brinson

Gangoli

Kumar

et al. 2019

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Herein, we report the successful use of newspaper as a substrate for the growth of single-walled carbon nanotubes (SWCNTs) by chemical vapor deposition (CVD) with intriguing results demonstrating that (a) the large surface area of newspaper stock allows for SWCNT growth and (b) only newspaper produced with kaolin clay sizing allowed for SWCNT growth. Kaolin newsprint was impregnated with Al2O3 and Fe(NO3)3·9H2O (as precursors to FexOy nanoparticles), and calcined (30 min at 400 °C). The subsequent char residue was loaded into a CVD chamber and used as a substrate for SWCNT growth at 750 °C, using H2, C2H2, and water vapor as the growth gas. Samples of raw carbon soot exhibiting fluorescence spectra, indicative of SWCNTs, were further evaluated by resonant Raman spectroscopy, and by transmission electron microscopy (TEM). The calcinated substrate remnants were evaluated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Experiments utilizing paper substrates produced with kaolin filler resulted in hybridized sp2–sp3 bonded carbon species. The soot was found to consist primarily of carbon nanotubes and bi-layer graphene in the form of collapsed nanotubes, also known as graphene nanoribbons (GNR).

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“…Lower carbon molecules, when used with ferrocene as a catalyst in a CVD reactor, produce SWCNTs [10][11][12], whereas by using the same catalyst with higher carbon molecules (e.g., toluene, p-xylene, or n-hexane) MWCNTs can be produced [1,13,14]. Iron (Fe), cobalt (Co), and nickel (Ni) are well known efficient catalysts for CNTs synthesis in CVD reactors [15].…”

Section: Introductionmentioning

confidence: 99%

“…reported that only 1.0 g/h of CNTs could be obtained on a flat substrate of quartz plate [25]. Craddock and Weisenberger (2015) proposed a scheme in which walls of the reactor lead to substrate-free method for production of CNTs [14]. Thus, in this work a quartz wall of an injection vertical CVD (IVCVD) reactor has been used as a substrate-free system for CNT synthesis.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Synthesis of Substrate-Free, Aligned and Tailored High Aspect Ratio Multiwall Carbon Nanotubes in an Ultrasonic Atomization Head CVD Reactor

Rabbani

Malaibari

Atieh

et al. 2016

Journal of Nanomaterials

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Chemical vapor deposition (CVD) method has proven its benchmark, over other methods, for the production of different types of carbon nanotubes (CNT) on commercial and lab scale. In this study, an injection vertical CVD reactor fitted with an ultrasonic atomization head was used in a pilot-plant scale (height 274 cm, radius 25 cm) for semicontinuous production of multiwall carbon nanotubes (MWCNTs). p-Xylene was used as a hydrocarbon precursor in which ferrocene was dissolved and provided the cracking catalyst. Atomization of the feed solution resulted in full and even dispersion of the catalytic solution. This dispersion led to the production of high aspect ratio MWCNTs (ranging from 8,000 to 12,000) at 850°C. Different experimental parameters affecting the quality and quantity of the produced CNTs were investigated. These included temperature, reaction time, and flow rate of the reaction and carrier gases. Different properties of the produced CNTs were characterized using SEM and TEM, while TGA was used to evaluate their purity. Specific surface area of selected samples was calculated by BET.

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Harvesting of large, substrate-free sheets of vertically aligned multiwall carbon nanotube arrays

Cited by 7 publications

References 10 publications

Activated Carbon, Carbon Nanofiber and Carbon Nanotube Supported Molybdenum Carbide Catalysts for the Hydrodeoxygenation of Guaiacol

Activated Carbon, Carbon Nanofiber and Carbon Nanotube Supported Molybdenum Carbide Catalysts for the Hydrodeoxygenation of Guaiacol

From Newspaper Substrate to Nanotubes—Analysis of Carbonized Soot Grown on Kaolin Sized Newsprint

Catalytic Synthesis of Substrate-Free, Aligned and Tailored High Aspect Ratio Multiwall Carbon Nanotubes in an Ultrasonic Atomization Head CVD Reactor

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