Large-scale synthesis and characterization of carbon spheres prepared by direct pyrolysis of hydrocarbons

Jin, Yizheng; Gao, Chao; Hsu, Wen Kuang; Zhu, Yan; Huczko, A.; Bystrzejewski, M.; Roe, Martin; Lee, Chi Young; Acquah, Steve F. A.; Kroto, Harold W.; Walton, D. R. M.

doi:10.1016/j.carbon.2005.03.002

Cited by 280 publications

(186 citation statements)

References 24 publications

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“…The pattern shows two peak at 26 and 45 corresponding to carbon peaks. The PXRD of both samples show that the peaks are broad; an observation that is attributed to low graphitisation of the sample [31]. No differences were noted between the two PXRD patterns indicating that the Ar had no impact on the CS structure.…”

Section: Effect Of C 2 H 2 Flow Rate and Temperaturementioning

confidence: 91%

Controlled syntheses of carbon spheres in a swirled floating catalytic chemical vapour deposition vertical reactor

Mhlanga

Coville

Iyuke

et al. 2010

Journal of Experimental Nanoscience

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Onion-like graphite structures, also called carbon spheres (CSs), represent another new allotropic nanophase of carbon materials, which can be potentially used as single electron devices, magnetic refrigerators, nanodiodes, nanotransistors, nanoball bearings, insulator lubricants as well catalyst supports. In this study, carbon nanospheres were synthesised in a vertical swirled floating catalytic chemical vapour deposition reactor for the first time. This process allows for continuous and large scale production of these materials. The CSs were obtained by the pyrolysis of acetylene in an inert atmosphere. The effect of pyrolysis temperatures and the flow rate of argon carrier gas on the size, quality and quantity of the synthesised CSs were investigated. Transmission electron microscope analysis of the carbon material revealed graphitic spheres with a smooth surface and a uniform diameter that could be controlled by varying reaction conditions (size: 50-250 nm). The materials were spongy with very low density. The CS production rate was found to increase with the increase in pyrolysis temperature (900-1000 C) and with flow rates of the carbon source (70-370 mL min À1 ) and carrier gas (70-480 mL min À1 ). Thermogravimetric analysis, powder X-ray diffraction and carbon, hydrogen and nitrogen analysis of the samples revealed that the products mainly contained CSs (98% carbon) and Raman spectroscopy revealed that the degree of graphitisation increased with the increase in pyrolysis temperature (900-1000 C).

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Section: Effect Of C 2 H 2 Flow Rate and Temperaturementioning

confidence: 91%

Controlled syntheses of carbon spheres in a swirled floating catalytic chemical vapour deposition vertical reactor

Mhlanga

Coville

Iyuke

et al. 2010

Journal of Experimental Nanoscience

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“…2). The accretion of spheres into clusters of several microns (see SI 5, ESI †) was described by Kroto et al for feeding times higher than 10 min, 34 or by Pol and co-workers as a result of cooling the system from high temperature to room temperature. 35 Anyway, it is worth noting that this coalescence is related to the presence of reactive dangling bonds on the surface, which gives them a high surface reactivity.…”

Section: Resultsmentioning

confidence: 95%

“…SI 2.2, ESI †). 34 Inagaki 6,7 reported that the most probable mechanism for the formation of carbon spheres consists of the dissociation of ethylene (carbon source) at 900 1C into C and H. After that C starts to polymerize forming the so-called basic structural units (BSUs), whilst methane and hydrogen are also formed. Usually, the arrangement of these BSUs leads to three different textures in these carbon forms: concentric, radial and random.…”

Section: Resultsmentioning

confidence: 99%

“…1400 cm À1 can be found, related to the C-H bending mode. 34 Furthermore, thermogravimetric analysis (TGA) and differential thermal analysis (DTA) experiments in air and under a N 2 atmosphere up to 900 1C were carried out. The thermogravimetric profile reveals that CS are stable in air below 530 1C; at ca.…”

Section: Resultsmentioning

confidence: 99%

“…In contrast, this effect is not seen in N 2 . 34,41 After studying the structural properties of the spheres, their morphology was unveiled by means of FESEM and HRTEM, depicting the spherically characteristic shape of CS, with a large quantity of them usually forming aggregates (Fig. 2).…”

Section: Resultsmentioning

confidence: 99%

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CVD synthesis of carbon spheres using NiFe-LDHs as catalytic precursors: structural, electrochemical and magnetoresistive properties

et al. 2016

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The gram-scale synthesis of carbon spheres with a diameter of ca. 740 nm has been achieved by means of a chemical vapour deposition method using NiFe-layered double hydroxides as a solid catalytic precursor. The presence of the catalyst (FeNi 3 ) allows controlling the final size distribution, resulting in a monodisperse sample. Their structural properties exhibited a high degree of graphitization according to their I D /I G ratio. In addition, their morphological features were unveiled by FIB-SEM and HRTEM, showing that they are formed by solid inner cores, and presenting labile chain-like structures due to accretion procedures. The solution and posterior sonication of the samples in toluene gave rise to the well-defined isolated spheres. The textural and electrochemical properties of the spheres have been tested showing non-mesoporous structures with a good behaviour as electrode materials for supercapacitors due to the presence of redox functionalities on their surface. Finally, magneto-transport measurements have been carried out, demonstrating semiconductor behaviour, as well as a positive magnetoresistance effect (ca. 72%) for the lowest studied temperature (2 K).

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The Use of CaCO ₃ and Ca ₃ (PO ₄ ) ₂ as Supports for Fe‐Co Catalysts for Carbon Nanotube Synthesis: A Comparative Study

Mhlanga¹,

Ray²,

Coville³

2010

Nanostructured Materials and Nanotechnology IV

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Large-scale synthesis and characterization of carbon spheres prepared by direct pyrolysis of hydrocarbons

Cited by 280 publications

References 24 publications

Controlled syntheses of carbon spheres in a swirled floating catalytic chemical vapour deposition vertical reactor

Controlled syntheses of carbon spheres in a swirled floating catalytic chemical vapour deposition vertical reactor

CVD synthesis of carbon spheres using NiFe-LDHs as catalytic precursors: structural, electrochemical and magnetoresistive properties

The Use of CaCO ₃ and Ca ₃ (PO ₄ ) ₂ as Supports for Fe‐Co Catalysts for Carbon Nanotube Synthesis: A Comparative Study

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Large-scale synthesis and characterization of carbon spheres prepared by direct pyrolysis of hydrocarbons

Cited by 280 publications

References 24 publications

Controlled syntheses of carbon spheres in a swirled floating catalytic chemical vapour deposition vertical reactor

Controlled syntheses of carbon spheres in a swirled floating catalytic chemical vapour deposition vertical reactor

CVD synthesis of carbon spheres using NiFe-LDHs as catalytic precursors: structural, electrochemical and magnetoresistive properties

The Use of CaCO 3 and Ca 3 (PO 4 ) 2 as Supports for Fe‐Co Catalysts for Carbon Nanotube Synthesis: A Comparative Study

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The Use of CaCO ₃ and Ca ₃ (PO ₄ ) ₂ as Supports for Fe‐Co Catalysts for Carbon Nanotube Synthesis: A Comparative Study