Effect of gaseous and condensate products of ethanol decomposition on aerosol CVD synthesis of single-walled carbon nanotubes

Shandakov, Sergey D.; Kosobutsky, А. V.; Рыбаков, М. С.; Sevostyanov, О. G.; Russakov, D. М.; Lomakin, M. V.; Vershinina, A. I.; Chirkova, I. М.

doi:10.1016/j.carbon.2017.10.064

Cited by 42 publications

(16 citation statements)

References 40 publications

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“…The reaction was terminated at 1.5 h when the catalyst bed was severely blocked, and the gas flowrate dropped to below 3 cm 3 STP/min even when the entering feed pressure was increased to >3.5 bar. The ability of CO/CH 4 mixture to form CNTs with faster kinetic rates and higher conversions than the single gas feeds was previously observed in the literature and attributed to reactions (2) and (3) but at much higher reaction temperatures (>700 • C) [28]. The reaction Gibbs free energy (∆G r ) of the exothermic CO disproportionation increases and that of the CH 4 decomposition decreases with increasing temperature with ∆G r = − 28 kJ/mol for the former and ∆G r = + 12.4 kJ/mol for the latter at 500 • C [29].…”

Section: Pure Ch 4 Feesupporting

confidence: 54%

“…These results strongly suggest that CH4 decomposition is very limited at such a low temperature and, thus, CH4 was unlikely a main source for the fast MWCNT growth in the WGS MR. For the feed of 80 v.%CO + 20 v.%CH 4 gas mixture, the experiments were performed at a feed flowrate of~15 cm 3 STP/min when the reactor inlet and exit pressures were maintained at~1.2 bar and atmospheric pressure (~1.013 bar), respectively. The reaction temperature was 500 • C, which was markedly lower than those required for CNT production by CVD on metallic catalysts from either of the single gases or the mixtures by [7,[26][27][28]. The carbon deposition was found to be very fast and only one sample of the gas product could be analyzed after~25 min of reaction when the drop in gas flowrate by carbon blocking was less than 30%.…”

Section: Pure Ch 4 Feementioning

confidence: 99%

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Carbon Nanotube Formation on Cr-Doped Ferrite Catalyst during Water Gas Shift Membrane Reaction: Mechanistic Implications and Extended Studies on Dry Gas Conversions

et al. 2020

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A nanocrystalline chromium-doped ferrite (FeCr) catalyst was shown to coproduce H2 and multiwalled carbon nanotubes (MWCNTs) during water gas shift (WGS) reaction in a H2-permselective zeolite membrane reactor (MR) at reaction pressures of ~20 bar. The FeCr catalyst was further demonstrated in the synthesis of highly crystalline and dimensionally uniform MWCNTs from a dry gas mixture of CO and CH4, which were the apparent sources for MWCNT growth in the WGS MR. In both the WGS MR and dry gas reactions, the operating temperature was 500 °C, which is significantly lower than those commonly used in MWCNT production by chemical vapor deposition (CVD) method from CO, CH4, or any other precursor gases. Extensive ex situ characterizations of the reaction products revealed that the FeCr catalyst remained in partially reduced states of Fe3+/Fe2+ and Cr6+/Cr3+ in WGS membrane reaction while further reduction of Fe2+ to Fe0 occurred in the CO/CH4 dry gas environments. The formation of the metallic Fe nanoparticles or catalyst surface dramatically improved the crystallinity and dimensional uniformity of the MWCNTs from dry gas reaction as compared to that from WGS reaction in the MR. Reaction of the CO/CH4 mixture containing 500 ppmv H2S also resulted in high-quality MWCNTs similar to those from the H2S-free feed gas, demonstrating excellent sulfur tolerance of the FeCr catalyst that is practically meaningful for utilization of biogas and cheap coal-derived syngas.

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Section: Pure Ch 4 Feesupporting

confidence: 54%

Section: Pure Ch 4 Feementioning

confidence: 99%

Carbon Nanotube Formation on Cr-Doped Ferrite Catalyst during Water Gas Shift Membrane Reaction: Mechanistic Implications and Extended Studies on Dry Gas Conversions

et al. 2020

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“…During the last 15 years, aerosol CVD setups have been equipped with a number of catalyst producing setups: decomposition of catalyst precursors (ferrocene, iron pentacarbonyl, etc.) followed by sintering and in situ nucleation of nanotubes [34,35], hot-wire generator producing vapor of active metals [36], a spark discharge generator producing also vapor of active metals [28,37]. The last apparatus developed by Mustonen et al [28] has shown the smallest among the others length of carbon nanotubes (~ 4 µm), though only a small fraction of the metal particles produced was employed for SWCNT growth (0.4-3%) [37] while the most of the catalyst was subjected to exhaust.…”

Section: Introductionmentioning

confidence: 99%

A spark discharge generator for scalable aerosol CVD synthesis of single-walled carbon nanotubes with tailored characteristics

Krasnikov

Zabelich

Iakovlev

et al. 2019

Chemical Engineering Journal

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“…The third group of authors showed that Ni and Co catalysts had a similar effectiveness in the PECVD synthesis of nanotubes, which was higher than for Fe catalyst [ 88 ]. The observed differences were explained by different solubility and diffusion constants of carbon in metals and rates of integration of carbon into growing tubes [ 127 , 128 , 129 , 130 , 131 , 132 , 133 ].…”

Section: Resultsmentioning

confidence: 99%

Metal Cluster Size-Dependent Activation Energies of Growth of Single-Chirality Single-Walled Carbon Nanotubes inside Metallocene-Filled Single-Walled Carbon Nanotubes

Kharlamova

Kramberger

2021

Nanomaterials

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By combining in situ annealing and Raman spectroscopy measurements, the growth dynamics of nine individual-chirality inner tubes (8,8), (12,3), (13,1), (9,6), (10,4), (11,2), (11,1), (9,3) and (9,2) with diameters from ~0.8 to 1.1 nm are monitored using a time resolution of several minutes. The growth mechanism of inner tubes implies two successive stages of the growth on the carburized and purely metallic catalytic particles, respectively, which are formed as a result of the thermally induced decomposition of metallocenes inside the outer SWCNTs. The activation energies of the growth on carburized Ni and Co catalytic particles amount to 1.85–2.57 eV and 1.80–2.71 eV, respectively. They decrease monotonically as the tube diameter decreases, independent of the metal type. The activation energies of the growth on purely metallic Ni and Co particles equal 1.49–1.91 eV and 0.77–1.79 eV, respectively. They increase as the tube diameter decreases. The activation energies of the growth of large-diameter tubes (dt = ~0.95–1.10 nm) on Ni catalyst are significantly larger than on Co catalyst, whereas the values of small-diameter tubes (dt = ~0.80–0.95 nm) are similar. For both metals, no dependence of the activation energies on the chirality of inner tubes is observed.

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Effect of gaseous and condensate products of ethanol decomposition on aerosol CVD synthesis of single-walled carbon nanotubes

Cited by 42 publications

References 40 publications

Carbon Nanotube Formation on Cr-Doped Ferrite Catalyst during Water Gas Shift Membrane Reaction: Mechanistic Implications and Extended Studies on Dry Gas Conversions

Carbon Nanotube Formation on Cr-Doped Ferrite Catalyst during Water Gas Shift Membrane Reaction: Mechanistic Implications and Extended Studies on Dry Gas Conversions

A spark discharge generator for scalable aerosol CVD synthesis of single-walled carbon nanotubes with tailored characteristics

Metal Cluster Size-Dependent Activation Energies of Growth of Single-Chirality Single-Walled Carbon Nanotubes inside Metallocene-Filled Single-Walled Carbon Nanotubes

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