Electron microscopy characterization of nanostructured carbon obtained from chlorination of metallocenes and metal carbides

Ávila‐Brande, David; Urones‐Garrote, E.; Katcho, Nebil A.; Lomba, Enrique; Gómez-Herrero, A.; Landa-Cánovas, A.R.; Otero-Dı́az, L.C.

doi:10.1016/j.micron.2006.06.002

Cited by 10 publications

(9 citation statements)

References 40 publications

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“…It has been suggested that FeCl 3 can facilitate carbon dissolution, which is responsible for the creation of amorphous hollow carbon nanotubes upon the chlorination of ferrocene. [24,30] The contrast difference between the tubular structure and the tip in Figure 5 small amounts of FeCl 2 could be produced at low chlorine concentrations. [29] It is possible that the formation of FeCl 2 in Fe 3 C follows the same mechanism proposed for the chlorination of ferrocene.…”

Section: Nanostructures Of Unannealed Fe 3 C-cdcsmentioning

confidence: 94%

“…This is likely due to mild surface oxidation on the Fe 3 C precursor, which can result from a common passivation treatment at the end of Fe 3 C synthesis that requires exposure to dilute O 2 to create a non-reactive surface on the freshly prepared carbide. [24] The successful reduction of FeCl 3 particles during the annealing treatment demonstrates that there is some selective accessibility between the bulk gas phase and the trapped iron chloride nanoparticles. For instance, during the annealing treatment, for the case of longer chlorination time samples which contain FeCl 3 nanoparticles, H 2 gas is able to diffuse into a trapped FeCl 3 particle, reduces the particle to metallic Fe, and HCl gas is able to diffuse back out to the bulk phase.…”

Section: Nanostructures Of Annealed Fe 3 C-cdcsmentioning

confidence: 99%

“…Studies within the literature for certain carbides, such as NbC and SiC, show largely layer-by-layer extraction of the carbide precursor, leading to an undesirable and poorly distributed core of metal carbide. [23,24] However, other metal carbides should be investigated as there is good evidence in the literature that they would undergo a different extraction mechanism than layer-by-layer extraction.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of embedded iron nanoparticles in Fe3C-derived carbons

Mangarella

Ewbank

Dutzer

et al. 2014

Carbon

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Carbide-derived carbons with embedded Fe nanoparticles are synthesized by partial chlorination of iron carbide at 600 o C. Interestingly, the residual Fe studied by X-ray absorption near edge spectroscopy, scanning electron microscopy, and transmission electron microscopy show the extraction process does not follow a layer-by-layer extraction process, as proposed in the literature for the chlorination of other carbides. Instead, a large percentage of iron carbide converts to iron (II) and iron (III) chloride nanoparticles, which remain trapped within the resulting nanoporous carbon framework. Further reductive treatment can be used to produce dispersed Fe nanoparticles with an average particle diameter approaching 10nm.

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Section: Nanostructures Of Unannealed Fe 3 C-cdcsmentioning

confidence: 94%

Section: Nanostructures Of Annealed Fe 3 C-cdcsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis of embedded iron nanoparticles in Fe3C-derived carbons

Mangarella

Ewbank

Dutzer

et al. 2014

Carbon

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“…A large number of binary and ternary carbides have been used for CDC synthesis: Al 4 C 3 , B 4 C, BaC 2 , CaC 2 , Cr 3 C 2 , Fe 3 C, Mo 2 C, MoC, Nb 2 C, NbC, SiC, SrC 2 , Ta 2 C, TaC, Ti 2 AlC, Ti 3 AlC 2 , Ti 3 SiC 2 , TiC, VC, W 2 C, WC, and ZrC 18, 23, 33–58. Using the same technique and temperatures as for carbide chlorination, porous CDC nanostructures were also reported for, e.g., carbonitrides, carbide‐nitride composites, such as ZrC/ZrN 15 and SiC/Si 3 N 4 5 or carbon and metal containing substances other than carbides such as ferrocene (Fe(C 5 H 5 ) 2 ) 59–61…”

Section: Cdc Synthesis and Structurementioning

confidence: 99%

Carbide‐Derived Carbons – From Porous Networks to Nanotubes and Graphene

Presser

Heon

Gogotsi

2011

Adv Funct Materials

608

492

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from carbides has attracted special attention lately. [ 3,4 ] Carbide-derived carbons (CDCs) encompass a large group of carbons ranging from extremely disordered to highly ordered structures ( Figure 1 ). The carbon structure that results from removal of the metal or metalloid atom(s) from the carbide depends on the synthesis method (halogenation, hydrothermal treatment, vacuum decomposition, etc.), applied temperature, pressure, and choice of carbide precursor.The growing interest in this fi eld is refl ected by a rapidly increasing number of publications and patents. A signifi cant progress in CDC research has been seen in several fi elds. Various carbide precursors have been systematically studied. Studies on binary carbides with different grain sizes show the possibility of low-temperature carbon formation for nanopowders. Also, a better understanding of graphene formation during high-temperature vacuum decomposition of silicon carbide has been achieved since SiC single crystals are now available in large sizes with extremely low defect concentrations and an almost atomically fl at surface fi nish. [ 8 ] CDC applications as electrode materials in electric double layer capacitors have attracted much attention lately. [ 9 ] The unique properties of porous CDC obtained by halogenation, such as a high specifi c surface area and tunable pore size with a narrow size distribution, make it an ideal material for sorbents or supercapacitor electrodes. CDCs have been derived from many precursors (SiC, TiC, Mo 2 C, VC, etc.) using a variety of treatment conditions that lead to a broad range of useful properties. Furthermore, graphene, [ 10 ] nanotubes, [ 11 ] and even nanodiamond [ 12 ] can be produced from carbide precursors. Their applications naturally differ from those of porous CDC.The last comprehensive journal review on this subject was published about fi fteen years ago in Russian; [ 13 ] book chapters published later [ 3,4 , 14 ] are less accessible and require updating due to rapid progress in the fi eld over the past few years. The most recent review of CDC [ 14 ] covers only energy-related applications. Therefore, a comprehensive review on the fi eld is long overdue. The goal of this article is to show how a variety of carbon structures can be produced from carbides, to explain how those structures can be controlled on the nanometer and subnanometer scale, and to describe CDC properties that are benefi cial for a number of applications. Carbide-Derived Carbons -From Porous Networks to Nanotubes and GrapheneCarbide-derived carbons (CDCs) are a large family of carbon materials derived from carbide precursors that are transformed into pure carbon via physical (e.g., thermal decomposition) or chemical (e.g., halogenation) processes. Structurally, CDC ranges from amorphous carbon to graphite, carbon nanotubes or graphene. For halogenated carbides, a high level of control over the resulting amorphous porous carbon structure is possible by changing the synthesis conditions and carbide precursor. The large number of...

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“…3 A particular class of materials with a variety of differently shaped nanostructures can be derived from the process of chlorination of metal carbides 4-6 and metallocenes. [7][8][9] Among the many structures that electron microscopy studies have revealed to exist in these materials, a major product of disordered carbons obtained from cobaltocene and ferrocene [7][8][9] precursors ͑in contrast to metal carbides 5,6 ͒ is a conglomerate of spherical particles ͑see Fig. 1͒ with diameters ranging from 1000 to 4000 Å.…”

Section: Introductionmentioning

confidence: 99%

Structure of carbon nanospheres prepared by chlorination of cobaltocene: Experiment and modeling

Katcho¹,

Zetterström²,

Lomba³

et al. 2008

Phys. Rev. B

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With the concourse of a variety of experimental techniques ͑neutron diffraction, x-ray photoelectron spectroscopy, 13 C nuclear magnetic resonance, electron microscopy, and Raman spectroscopy͒ and a combination of reverse Monte Carlo, molecular dynamics, and Monte Carlo simulations, we propose a model for the microscopic structure of a sample of carbon nanospheres obtained from chlorination of cobaltocene. The sample, which exhibits a high porosity, is shown to be formed by a series of interconnected sheets of graphene. Despite the large degree ͑Ϸ80%͒ of sp 2 hybridization shown by carbon atoms, there is a non-negligible amount of sp 3 -bonded carbons, some of them acting as links between graphene sheets. The transmission electron microscopy images simulated from the microscopic structure, which is extracted from the neutron diffraction data by a mixed reverse Monte Carlo-molecular dynamics/Monte Carlo procedure, agree remarkably well with the experimental results.

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Electron microscopy characterization of nanostructured carbon obtained from chlorination of metallocenes and metal carbides

Cited by 10 publications

References 40 publications

Synthesis of embedded iron nanoparticles in Fe3C-derived carbons

Synthesis of embedded iron nanoparticles in Fe3C-derived carbons

Carbide‐Derived Carbons – From Porous Networks to Nanotubes and Graphene

Structure of carbon nanospheres prepared by chlorination of cobaltocene: Experiment and modeling

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