Electron diffraction investigation of catalytic particles at the tips of carbon nanotubes

Gur’yanova, O. M.; Kukovitsky, E. F.; L’vov, S.G.; Sainov, N. A.; Shustov, V. A.

doi:10.1134/1.1462676

Cited by 7 publications

(2 citation statements)

References 5 publications

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“…The absence of carbidic phase is expected, as Ni carbide is not stabile at 550 o C [76]. Similarly the presence of metallic state and the absence of carbidic phase of Ni catalyst were previously reported after deactivation from the catalytic carbon support gasification, after graphitization of the amorphous carbon film, and during and after CNT growth [44,63,65,[77][78][79][80][81]. Catalytic gasification, CNT and CNF growth, and catalytic graphitization presumably involve a similar general mechanism of carbon atoms dissolutions, diffusion and precipitation from the catalyst Ni particles [56,65].…”

Section: The Effect Of the Subsequent Treatment To The Cnf/ac Compositesupporting

confidence: 62%

Controlling the yield and structure of carbon nanofibers grown on a nickel/activated carbon catalyst

Rinaldi

Abdullah

Ali

et al. 2009

Carbon

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Carbon nanofibers (CNFs) were grown via the chemical vapor deposition of C2H4 on an activated carbon (AC)-supported Ni catalyst. The texture of the CNF/AC composites can be tuned by varying the growth temperature and by treatment in reducing atmosphere prior to C2H4/H2 exposure. The Ni-catalyzed gasification of the AC support increases the microporosity of the composite and shown to be dominant throughout the composite synthesis especially during reduction, subsequent treatment in reducing atmosphere, and CNF growth at low temperatures. N2 isotherm and scanning electron microscope were used to characterize the texture and morphology of the composites. Subsequent treatment in reducing atmosphere were shown to increase the Ni catalyst activity to grow CNFs. High resolution transmission electron microscope however did not reveal any microstructural difference for Ni catalyst with and without the subsequent reduction treatment. We propose in this paper that the carbon dissolutions during treatment of the catalyst might have an implication on the CNF growth.

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Section: The Effect Of the Subsequent Treatment To The Cnf/ac Compositesupporting

confidence: 62%

Controlling the yield and structure of carbon nanofibers grown on a nickel/activated carbon catalyst

Rinaldi

Abdullah

Ali

et al. 2009

Carbon

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“…The nickel carbide could be found at catalytic reactions [4], carbon nanowhiskers and nanotubes [5]. The Ni3C carbide is a metastable compound obtained by different techniques, including nonequilibrium methods, such as carbon ion implantation into Ni [6], diffusion reactions of nickel and amorphous carbon films [7,8], chemical synthesis [9], and plasma deposition [10].…”

Section: Introductionmentioning

confidence: 99%

Features of cubic Ni3C and NiC carbides obtained by HT-HP sintering

Nakonechna

Stratiіchuk

Kuryliuk

et al. 2022

Phys. Chem. Solid St.

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In this work NiC carbides were manufactured by HP-HT sintering of mechanically alloyed charges of the elemental Ni–carbon nanotubes (CNT) or Ni–Graphite. Structural features of the materials obtained were characterized by X-ray diffraction and scanning electron microscopy. X-ray diffraction studies have revealed that the crystal lattice of nickel carbide obtained from mechanically alloyed Ni–CNT charge is supplemented with additional Carbon atoms from the graphite shell of the high-pressure cell at HT-HP sintering. On the other hand, nickel carbide fabricated from mechanically alloyed Ni–Graphite charge retains its composition. It is shown that materials studied in this work demonstrate an advanced value of microhardness (up to 7 GPa).

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Near‐Quantitative Solid‐State Synthesis of Carbon Nanotubes from Homogeneous Diphenylethynecobalt and –Nickel Complexes

2003

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Carbon nanotubes (CNTs) have generated a tremendous amount of research interest because of their unique structural, electronic, magnetic, and mechanical properties. [1] Among the various synthetic methods employed for their preparation, chemical vapor deposition (CVD) has emerged to be most effective, and efforts are increasing in applying this technique to pre-growth device fabrication by utilizing (in particular lithographically) [2] patterned catalyst arrays and in situ tube assembly. [2,3] Crucial in this endeavor is the sitespecific batch production of ordered carbon with control of stoichiometry and ultimately morphology. One possible approach to achieving this would be the efficient thermal conversion of a defined, soluble, molecular organometallic precursor composed of both the carbon source and the metal catalyst, placed locospecifically by wetting and drying. Such a strategy would combine the advantages of the floating organometallic catalyst (for example, ferrocene, [Fe(CO) 5 ], etc.) CVD methodology [1d, 4] with a solid-state conversion of carbon precursors. Reports of the latter reveal some serious shortcomings with respect to yield and/or degree of graphitization, extremity of conditions, need for specialized equipment, the requirement of co-reagents, and simplicity of starting materials. [1d, 5] We have described the solid-state thermolysis of a [Co 2 (CO) 6 ]-complexed tetrabenzodehydro [20]annulene and some of its substructures to form ordered carbon material, but this method shared some of these drawbacks, in as much as the highest yields were only about 60 %. The desired product consisted of an (at best) approximately equal mixture of multiwalled tubes (MWNTs)

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Electron diffraction investigation of catalytic particles at the tips of carbon nanotubes

Cited by 7 publications

References 5 publications

Controlling the yield and structure of carbon nanofibers grown on a nickel/activated carbon catalyst

Controlling the yield and structure of carbon nanofibers grown on a nickel/activated carbon catalyst

Features of cubic Ni3C and NiC carbides obtained by HT-HP sintering

Near‐Quantitative Solid‐State Synthesis of Carbon Nanotubes from Homogeneous Diphenylethynecobalt and –Nickel Complexes

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