Synthesis and study of carbon microspheres for use as catalyst support for cobalt

Mhlanga, Sabelo D.; Mondal, Kartick Chandra; Naidoo, Nicolette; Kunjuzwa, Niki; Witcomb, M. J.; Coville, Neil J.

doi:10.4102/sajs.v105i7/8.87

Cited by 14 publications

(27 citation statements)

References 22 publications

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“…The inner diameter remained the same (∼10 nm) throughout the synthesis period. 22 The results indicate that the yield increases due to deposition of carbon onto the tubes and not due to the formation of more tubes. 19 Delivered by Ingenta to: Nanyang Technological The tubes not only become bigger in size with time, but they break into smaller fragments with time.…”

Section: Effect Of Excess Carbon Deposition On the Cnt Morphologymentioning

confidence: 86%

“…Further details can be found in Ref. [22]. Prior to evaluation of the effect of carbon deposition on the morphology of the carbons (tubes, spheres, coils) the chemical composition of the carbon materials was evaluated.…”

Section: Characterization Of Cntsmentioning

confidence: 99%

“…22 The furnace was electronically controlled such that the heating rate, reaction temperature and gas flow rates could be accurately maintained as desired. The catalyst was loaded into a quartz boat (120 mm × 15 mm) at room temperature and the boat was placed in the centre of the quartz tube.…”

Section: Carbon Nanotube Synthesis On a Caco 3 Supportmentioning

confidence: 99%

“…In a previous report we noted that the synthesis of CNTs over CaCO 3 supports gave thickened products that were shorter than the original CNTs. 22 The stub-like CNT pieces indicated that the tubes had fragmented. In other studies, 23 24 we have shown that CNTs prepared over CaCO 3 contained residual Ca ions and these impacted, via 'docking stations,' on the catalytic activity of metals supported on the synthesized CNTs.…”

Section: Introductionmentioning

confidence: 99%

“…Further, in terms of their tensile strength and elastic modulus, it has been reported that CNTs are the strongest materials known. 11 Since 2002, 12 the number of studies reporting the synthesis of CNTs using CaCO 3 as a support has been increasing at a fast rate [13][14][15][16][17][18][19][20][21][22] and most of the factors affecting the CNT growth over this support have been considered in these studies. Such factors include: (i) The catalyst properties such as the type of catalyst (monometallic, bimetallic), the catalyst precursor, the support and the concentration of catalyst on the support.…”

Section: Introductionmentioning

confidence: 99%

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A Facile Procedure to Shorten Multiwalled Carbon Nanotubes

Mhlanga

Coville²

2010

J. Nanosci. Nanotech.

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Multi-walled carbon nanotubes (MWCNTs) with > 95% purity were synthesized over a Fe-Co/CaCO3 catalyst using chemical vapour deposition (CVD). Both the CNT yield and the outer diameters increased with time on line in the presence of acetylene. More significantly, the tubes were reduced in length and became stub-like with time. TEM analysis revealed that the CNTs commenced shortening after 2 h of reaction time. Reagent residues (e.g., Ca, CaO, OH/COOH groups and Fe-Co oxides) were found not to influence the CNT bond breaking reaction. CNT growth over Fe-Co supported on silica or CaCO3-Ca3(PO4)2 gave similar results. Further, MWCNTs produced by a floating catalyst method, carbon helices produced from Fe-Co-In/A2O3, and N doped CNTs also revealed tube shortening as a function of reaction time under a flow of acetylene. It is thus apparent that MWCNTs can readily be shortened by the facile procedure of depositing carbon from excess C2H2 on the outer walls of CNTs.

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Section: Effect Of Excess Carbon Deposition On the Cnt Morphologymentioning

confidence: 86%

Section: Characterization Of Cntsmentioning

confidence: 99%

Section: Carbon Nanotube Synthesis On a Caco 3 Supportmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Facile Procedure to Shorten Multiwalled Carbon Nanotubes

Mhlanga

Coville²

2010

J. Nanosci. Nanotech.

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Preparation of Highly Stable and Electrochemically Active Three‐dimensional Interconnected Graphene Frameworks from Jute Sticks

Shah

Yang

Ashraf

et al. 2022

Chemistry An Asian Journal

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Over the past few years, the environmentally friendly synthesis of nanomaterials, including graphene using green chemistry, has attracted tremendous attention due to its easy handling, low cost, and biocompatibility. Here we demonstrate a facile and efficient green synthesis route for producing highly stable and electrochemically active threedimensional interconnected graphene frameworks (3DIGF) from jute sticks. Initially, jute sticks derived three-dimensional amorphous activated carbon nanosheets (3DAACNs) were prepared at low temperatures (i. e., 850 °C) in an inert environment. The resultant 3DAACNs were then heat treated at a high temperature (i. e., 2700 °C) under an inert environment, resulting in 3DIGF. The prepared carbonaceous materials were fully characterized, and various experimental techniques confirmed the preparation of 3DIGF. The prepared 3DIGF shows a highly stable nature in thermal and chemical environments and demonstrates a highly dynamic nature for the electrooxidation of sulfide. This study could be considered a vital contribution towards the economic and simple approach for preparing 3DIGF from biomass.

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