Growth of CNTs on Fe–Si catalyst prepared on Si and Al coated Si substrates

Teng, Fei; Ting, Jyh‐Ming; Sharma, Shabnam; Liao, Kuo–Fu

doi:10.1088/0957-4484/19/9/095607

Cited by 25 publications

(20 citation statements)

References 31 publications

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“…A small reduction in the particle size was anticipated, as the fly ash particles were entrained in the CNFs, hence reducing their agglomeration. Likewise, although the CNFs are known to be hydrophobic and not easily dispersed in water [45], the entrained fly ash most probably enhanced their solubility. Both of these materials were then introduced into a Dolapix polymer solution.…”

Section: Resultsmentioning

confidence: 99%

Direct synthesis of carbon nanofibers from South African coal fly ash

et al. 2014

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Carbon nanofibers (CNFs), cylindrical nanostructures containing graphene, were synthesized directly from South African fly ash (a waste product formed during the combustion of coal). The CNFs (as well as other carbonaceous materials like carbon nanotubes (CNTs)) were produced by the catalytic chemical vapour deposition method (CCVD) in the presence of acetylene gas at temperatures ranging from 400°C to 700°C. The fly ash and its carbonaceous products were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), laser Raman spectroscopy and Brunauer-Emmett-Teller (BET) surface area measurements. It was observed that as-received fly ash was capable of producing CNFs in high yield by CCVD, starting at a relatively low temperature of 400°C. Laser Raman spectra and TGA thermograms showed that the carbonaceous products which formed were mostly disordered. Small bundles of CNTs and CNFs observed by TEM and energy-dispersive spectroscopy (EDS) showed that the catalyst most likely responsible for CNF formation was iron in the form of cementite; X-ray diffraction (XRD) and Mössbauer spectroscopy confirmed these findings.

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Section: Resultsmentioning

confidence: 99%

Direct synthesis of carbon nanofibers from South African coal fly ash

et al. 2014

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“…The first two methods impose problems in scaling up the production up to industrial level while the chemical vapour deposition (CVD) method offers the best hope for large scale production of CNTs. A catalyst is usually needed for the synthesis of CNTs, the most commonly used catalysts are either organo-metallic compounds such as cobaltocene, ferocene, nicklocene, or metal catalyst powder or thin films [9][10][11][12][13]. Different substrates (such as quartz, silicon wafers, alumina, aluminosilicates etc.)…”

Section: Introductionmentioning

confidence: 99%

Morphology study of carbon nanospecies grown on carbon fibers by thermal CVD technique

Sharma

Lakkad

2009

Surface and Coatings Technology

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“…It was reported that the thickness of the Al layer could be responsible for controlling the length of CNTs. [27][28][29][30] The impact was mainly attributed to the diffusion of Al into the catalyst layer leading to a decrease in the carbon solubility in the catalyst particles. As shown in the literature, the decrease in the carbon solubility resulted in shorter CNTs as the Al layer thickness increases.…”

Section: Resultsmentioning

confidence: 99%

Simultaneous growth of self-patterned carbon nanotube forests with dual height scales

et al. 2012

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In this study, we report on a unique, one-step fabrication technique enabling the simultaneous synthesis of vertically aligned multi-walled carbon nanotubes (VA-MWCNTs) with dual height scales through alcohol catalyzed chemical vapor deposition (ACCVD). Regions of VA-MWCNTs with different heights were well separated from each other leading to a self-patterning on the surface. We devised a unique layer-by-layer process for application of catalyst and inhibitor precursors on oxidized Si (100) surfaces before the ACCVD step to achieve a hierarchical arrangement. Patterning could be controlled by adjusting the molarity and application sequence of precursors. Contact angle measurements on these self-patterned surfaces indicated that manipulation of these hierarchical arrays resulted in a wide range of hydrophobic behavior changing from that of a sticky rose petal to a lotus leaf.Inspired by the self-cleaning effect of lotus leaves, researchers have paid increasing attention to the generation of superhydrophobic surfaces having hierarchical structures with features ranging from micro-to nanoscale. The lotus leaf has a highly textured surface with protruding nubs (20-40 mm) which are further covered with nanometre sized wax crystals.1 Lotus leaf-like surfaces can be created either by covering a rough surface with a low surface energy material or by roughening/ etching/patterning the surface of a hydrophobic material. 10,11Functionalized vertically aligned multi-walled carbon nanotube (VA-MWCNT) arrays synthesized by CVD have also demonstrated superhydrophobic properties. 9,12Moreover, combining the CVD technique with photolithography for generating patterned carbon nanotube (CNT) arrays on surfaces has also been shown to improve and tailor superhydrophobicity of these surfaces.13 However, additional steps such as patterning with lithography for creating complex structures to improve hydrophobic behavior or imparting self-cleaning properties are not often cost efficient. Therefore, a simple, one-step production technique is required for the generation of artificial lotus leaf-like surfaces.Hence, the aim of this study is to imitate lotus leaf structures by creating dual-scale micro/nanostructures of aligned and patterned CNTs during the growth. For this purpose, we developed a unique technique based on the layer-by-layer application of catalyst and inhibitor precursors which is normally used to grow VA-MWCNTs by our group.14 By tuning the molarity, types, sequence and number of precursor and catalyst layers, we were able to not only generate hierarchical and patterned superhydrophobic VA-MWCNT arrays but also tailor the wettability properties. The resultant hierarchical structures were fully characterized (contact angle, surface topography, physical properties, and geometry) in order to identify the contribution of micro-and nano-structured aspects on water repellency. These hierarchical CNT arrays with micro-and nanoscales can be further developed to potentially find applications as self-cleaning dry-adhesives (gecko ...

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Growth of CNTs on Fe–Si catalyst prepared on Si and Al coated Si substrates

Cited by 25 publications

References 31 publications

Direct synthesis of carbon nanofibers from South African coal fly ash

Direct synthesis of carbon nanofibers from South African coal fly ash

Morphology study of carbon nanospecies grown on carbon fibers by thermal CVD technique

Simultaneous growth of self-patterned carbon nanotube forests with dual height scales

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