Synthesis, Laser Processing, and Flame Purification of Nanostructured Carbon

Wal, Randy L. Vander; Tomasek, Aaron J.; Ticich, Thomas M.

doi:10.1021/nl020232r

Cited by 28 publications

(25 citation statements)

References 29 publications

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“…concentric crystallites (Vander Wal et al, 2003). The X-ray diffraction analysis indicates that the carbon atoms of a primary soot particle are packed into hexagonal face-centered arrays commonly referred to as platelets.…”

Section: Detailed Kinetic Modeling Of Soot Formation During Shock-tubmentioning

confidence: 99%

DETAILED KINETIC MODELING OF SOOT FORMATION DURING SHOCK-TUBE PYROLYSIS OF C₆H₆: DIRECT COMPARISON WITH THE RESULTS OF TIME-RESOLVED LASER-INDUCED INCANDESCENCE (LII) AND CW-LASER EXTINCTION MEASUREMENTS

Naydenova

Nullmeier

Warnatz

et al. 2004

Combustion Science and Technology

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The results of calculations of the main parameters of the soot formation process (t, k f , SY, and r m ) carried out with the use of the detailed kinetic model of soot formation are compared with the experimental measurements of these parameters by the continuous-wave (CW)-laser extinction technique and by the time-resolved laser-induced incandescence (LII) method during C 6 H 6 pyrolysis behind reflected shock waves. The detailed kinetic model of soot formation that is developed incorporates the gas-phase mechanisms of acetylene pyrolysis and the mechanisms of formation of polyaromatic hydrocarbons, polyyne molecules, and pure carbon clusters. It combines the H abstraction=C 2 H 2 addition and polyyne pathways of the soot formation process. The formation, growth, and coagulation of soot precursors and soot particles are described within the framework of the discrete Galerkin technique based on an error-controlled expansion of the size distribution function of heterogeneous species into the orthogonal polynomials of a discrete variable (in particular, the number of monomers in the heterogeneous particle) that makes it possible to preserve a discrete character of any elementary transformations of heterogeneous particles and to describe them as elementary chemical reactions for the heterogeneous particles of all sizes. The comparison of the calculations with the experimental measurements of the induction time t, observable rate of soot particle growth, k f , and soot yield SY by the CW-laser extinction method in the pyrolysis of benzene=argon mixtures in shock-tube experiments clearly demonstrates that the coincidence is quantitatively good for all the main parameters of soot formation. A particular difference between the values of the mean soot particle radius r m experimentally measured by the time-resolved LII technique and calculated with the help of the detailed kinetic model is observed at the low and high temperatures. The results presented demonstrate the current level of the predictive capabilities of the detailed kinetic model of soot formation and the reliability of the time-resolved LII technique for the quantitative determination of the soot particle sizes.

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Section: Detailed Kinetic Modeling Of Soot Formation During Shock-tubmentioning

confidence: 99%

DETAILED KINETIC MODELING OF SOOT FORMATION DURING SHOCK-TUBE PYROLYSIS OF C₆H₆: DIRECT COMPARISON WITH THE RESULTS OF TIME-RESOLVED LASER-INDUCED INCANDESCENCE (LII) AND CW-LASER EXTINCTION MEASUREMENTS

Naydenova

Nullmeier

Warnatz

et al. 2004

Combustion Science and Technology

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“…There is a great interest in nanoforms of carbon, which is due to their novel properties and many potential uses [1]. One of several thermal approaches to these materials (e.g.…”

Section: Introductionmentioning

confidence: 99%

IR laser-induced metal ablation and dielectric breakdown in benzene

Santos

Díaz

Camacho

et al. 2010

Infrared Physics & Technology

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“…At the same time, we demonstrate that the formation of hollow SCNPs in our experiment has nothing to do with soot restructuring due to the ordering of basic structural units (BSUs), which has been recently reported in a hydrocarbon flame under pulsed irradiation from a Nd:YAG (YAG: yttrium aluminum garnet) laser. [10] The generation of SCNPs is governed by the direct growth of graphene sheets from precipitating acetylene molecules. The demonstration of the possibility of this latter process should be a significant contribution to the field of flame-formed carbon nanoparticles.…”

mentioning

confidence: 99%

Formation of Shell‐Shaped Carbon Nanoparticles Above a Critical Laser Power in Irradiated Acetylene

Choi¹,

et al. 2004

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In the last two decades, a series of novel nanostructured carbon materials have been synthesized in the laboratory, [1] including carbon nanotubes, [2] carbon onions, [3] and carbon nanocapsules. [4,5] Intensive studies of nanostructured carbon synthesis are motivated by potential applications such as intercalation materials for Li batteries, [6] gas-storage media, cold-electron field emitters, [7] etc. Consisting of bent graphene layers (GLs), these nanomaterials possess unique electric properties due to their finite characteristic size, making them attractive for such applications. Depending on the curvature of the graphene sheets, carbon nanomaterials can demonstrate metallic or semiconducting behavior. [8] As has been shown in our recent paper, [9] alternating metallic and semiconducting regions within carbon nanomaterials produces high levels of cold-electron field emission (FE) from nanostructured carbon materials. Therefore, there is a strong need to find an industrially attractive pathway to synthesize carbon nanoparticles with this structure. It is worth noting that although a variety of methods have been developed to produce carbon nanomaterials, these methods generate only a raw product requiring either further purification (e.g., after laser ablation or arc discharge) or the removal of catalysts (after chemical vapor deposition). Herein, we report a new synthesis pathway for generating onionlike shell-shaped carbon nanoparticles (SCNPs) which is a one-step process. Our SCNPs are highly crystalline and not mixed with other types of carbon, and therefore do not need further purification. Furthermore, our method does not use any catalysts. We show that a transparent acetylene flow can produce onion-like SCNPs (which have continuous bent GLs) in bulk quantities when it is exposed to external irradiation from a continuous-wave (CW) infrared CO 2 laser. The striking feature of this process is that it is launched only above a critical threshold of laser irradiance. Below the irradiance threshold, the flame generates carbon soot. It is this critical threshold phenomenon that distinguishes our work from any other work in the field of flame-formed carbon nanoparticles. At the same time, we demonstrate that the formation of hollow SCNPs in our experiment has nothing to do with soot restructuring due to the ordering of basic structural units (BSUs), which has been recently reported in a hydrocarbon flame under pulsed irradiation from a Nd:YAG (YAG: yttrium aluminum garnet) laser.[10] The generation of SCNPs is governed by the direct growth of graphene sheets from precipitating acetylene molecules. The demonstration of the possibility of this latter process should be a significant contribution to the field of flame-formed carbon nanoparticles. We also show that our SCNPs exhibit FE performance comparable to that of carbon nanotubes. Experiments have been carried out with the setup used successfully in our previous work.[11±15] The multi-nozzle-type burner allowed us to supply gases through different annular coaxia...

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Synthesis, Laser Processing, and Flame Purification of Nanostructured Carbon

Cited by 28 publications

References 29 publications

DETAILED KINETIC MODELING OF SOOT FORMATION DURING SHOCK-TUBE PYROLYSIS OF C₆H₆: DIRECT COMPARISON WITH THE RESULTS OF TIME-RESOLVED LASER-INDUCED INCANDESCENCE (LII) AND CW-LASER EXTINCTION MEASUREMENTS

DETAILED KINETIC MODELING OF SOOT FORMATION DURING SHOCK-TUBE PYROLYSIS OF C₆H₆: DIRECT COMPARISON WITH THE RESULTS OF TIME-RESOLVED LASER-INDUCED INCANDESCENCE (LII) AND CW-LASER EXTINCTION MEASUREMENTS

IR laser-induced metal ablation and dielectric breakdown in benzene

Formation of Shell‐Shaped Carbon Nanoparticles Above a Critical Laser Power in Irradiated Acetylene

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Synthesis, Laser Processing, and Flame Purification of Nanostructured Carbon

Cited by 28 publications

References 29 publications

DETAILED KINETIC MODELING OF SOOT FORMATION DURING SHOCK-TUBE PYROLYSIS OF C6H6: DIRECT COMPARISON WITH THE RESULTS OF TIME-RESOLVED LASER-INDUCED INCANDESCENCE (LII) AND CW-LASER EXTINCTION MEASUREMENTS

DETAILED KINETIC MODELING OF SOOT FORMATION DURING SHOCK-TUBE PYROLYSIS OF C6H6: DIRECT COMPARISON WITH THE RESULTS OF TIME-RESOLVED LASER-INDUCED INCANDESCENCE (LII) AND CW-LASER EXTINCTION MEASUREMENTS

IR laser-induced metal ablation and dielectric breakdown in benzene

Formation of Shell‐Shaped Carbon Nanoparticles Above a Critical Laser Power in Irradiated Acetylene

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DETAILED KINETIC MODELING OF SOOT FORMATION DURING SHOCK-TUBE PYROLYSIS OF C₆H₆: DIRECT COMPARISON WITH THE RESULTS OF TIME-RESOLVED LASER-INDUCED INCANDESCENCE (LII) AND CW-LASER EXTINCTION MEASUREMENTS

DETAILED KINETIC MODELING OF SOOT FORMATION DURING SHOCK-TUBE PYROLYSIS OF C₆H₆: DIRECT COMPARISON WITH THE RESULTS OF TIME-RESOLVED LASER-INDUCED INCANDESCENCE (LII) AND CW-LASER EXTINCTION MEASUREMENTS