Flame synthesis of carbon nanotubes and few-layer graphene on metal-oxide spinel powders

Memon, Nasir K.; Xu, Fusheng; Sun, Geliang; Dunham, Sage J. B.; Kear, B. H.; Tse, Stephen D.

doi:10.1016/j.carbon.2013.07.023

Cited by 46 publications

(17 citation statements)

References 43 publications

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“…Laminar flames are widely used for fundamental studies of soot formation [1][2][3][4] and the synthesis of materials [5][6][7][8]. Characterising such systems with accurate and reliable techniques is vital for understanding the processes controlling particle formation in flames and is an ongoing field of research [9].…”

Section: Introductionmentioning

confidence: 99%

Improved methodology for performing the inverse Abel transform of flame images for color ratio pyrometry

et al. 2019

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A new method is presented for performing the Abel inversion by fitting the line-of-sight projection of a predefined intensity distribution (FLiPPID) to the recorded 2D projections. The aim is to develop a methodology that is less prone to experimental noise when analysing the projection of antisymmetric objects, in this case co-flow diffusion flame images for colour ratio pyrometry. A regression model is chosen for the light emission intensity distribution of the flame cross-section as a function of the radial distance from the flame centre-line. The forward Abel transform of this model function is fitted to the projected light intensity recorded by a colour camera. For each of the three colour channels, the model function requires three fitting parameters to match the radial intensity profile at each height above the burner. This results in a very smooth Abel inversion with no artifacts such as oscillations or negative values of the light source intensity, as is commonly observed for alternative Abel inversion techniques, such as the basis-set expansion (BASEX) or onion-peeling. The advantages of the new FLiPPID method are illustrated by calculating the soot temperature and volume fraction profiles inside a co-flow diffusion flame, both being significantly smoother than those produced by the alternative inversion methods. The developed FLiPPID methodology can be applied to numerous other optical techniques for which smooth inverse Abel transforms are required.

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Section: Introductionmentioning

confidence: 99%

Improved methodology for performing the inverse Abel transform of flame images for color ratio pyrometry

et al. 2019

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“…The diameter of the CNTs are varied between 9 to 27nm. This variation is due to the myriad of catalyst nanoparticles of varying shapes and sizes produced on top of the nickel wire due to carbide-induce breakup process as shown in Fig.2 (d) 28 . Fig.2 (b) and (c) show SEM images at the outer and inner edge of the growth region respectively.…”

Section: Flame Synthesis Modelmentioning

confidence: 99%

Identification of CNT Growth Region and Optimum Time for Catalyst Oxidation: Experimental and Modelling Studies of Flame Synthesis

Hamzah¹,

Yasin²,

Yusop³

et al. 2019

Evergreen

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Control improvement of carbon nanotubes synthesis in flames requires synergistic computational and experimental studies. The present study investigated distribution of carbon nanotubes growth region within methane diffusion flame using acid dipped nickel wire. The carbon nanotubes growth occurred in a narrow range between 4 to 6 mm height above the burner. Nickel wire oxidation in nitric acid within 90 seconds to 260 seconds favors formation of carbon nanotubes. Prediction of the carbon nanotubes growth region using multi-scale modelling method achieved a reasonable agreement with the experimental results though the region of no growth was not reproduced due to the exclusion of soot formation modelling.

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“…Interestingly, it is noteworthy that the diameter of the catalyst particle is between the outer diameter and the inner diameter of the multi-walled carbon nanotubes, further indicating that the catalyst particle size determines the diameter of the carbon nanotubes to some extent, which is consistent with the results of Refs. [7,13,17]. Statistical analysis was performed using the Nano Measurer.…”

Section: Characterization Of Carbon Nanomaterials On Nickel Foam Subsmentioning

confidence: 99%

Flame Synthesis of Carbon Nanotubes on Different Substrates in Methane Diffusion Flames

Chu¹,

Han²,

Ren³

et al. 2018

ES Energy Environ.

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Characterized by their unique electrical, mechanical, and photonic properties, carbon nanotubes (CNTs) have generated a high level of research interest. Based on the study of methane coaxial jet diffusion flame, the effect of sampling substrate, sampling time and sampling height on the catalytic synthesis of CNTs was studied. The morphology and structure of carbon nanomaterials were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Raman spectroscopy. The interaction between the catalyst and the substrate was analyzed with nickel nitrate as catalyst precursor and copper, nickel-chromium and nickel foam as supported substrates, respectively. The experimental results showed that sampling time and sampling height had an important influence on CNTs. Copper and nickelchromium substrates provide open space for the synthesis of CNTs, resulting in more impurities. The unique voids of nickel foam provide excellent growth space for CNTs. SEM showed that the multi-walled CNTs were dense and uniform. TEM displayed that the catalyst particles were coated inside the CNTs. Raman spectroscopy indicated that the CNTs synthesized on copper substrates had the highest crystallinity and purity, followed by nickel-chromium and nickel foam substrates. The interaction between the catalyst and the substrate remarkably affected the growth mechanism and morphology of CNTs. The flame-synthesizing CNTs are based on the tip growth mode and the vapor-liquid-solid growth mechanism. Flame synthesis holds great potential for the cost-effective production of CNTs.

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Flame synthesis of carbon nanotubes and few-layer graphene on metal-oxide spinel powders

Cited by 46 publications

References 43 publications

Improved methodology for performing the inverse Abel transform of flame images for color ratio pyrometry

Improved methodology for performing the inverse Abel transform of flame images for color ratio pyrometry

Identification of CNT Growth Region and Optimum Time for Catalyst Oxidation: Experimental and Modelling Studies of Flame Synthesis

Flame Synthesis of Carbon Nanotubes on Different Substrates in Methane Diffusion Flames

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