Fullerenic carbon in combustion-generated soot

Grieco, William J.; Howard, Jack B.; Rainey, Lenore C.; Sande, J. B. Vander

doi:10.1016/s0008-6223(99)00149-9

Cited by 163 publications

(104 citation statements)

References 36 publications

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“…As we have shown, the nano onions identified by Iijima [1] and indicated in Figure 1 Comparing Howard's method [19,41] on the carbon fullerene production with the present procedure, we find that in this work the fullerenes are generated from the soot of premixed flames. Other important aspect of Howard's process is that the flame, from which the fullerene soot are produced, is surrounded by an annular non sooting flame, providing a thermal shield.…”

Section: Discussionsupporting

confidence: 61%

Method to obtain carbon nano-onions by pyrolisys of propane

2013

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Section: Discussionsupporting

confidence: 61%

Method to obtain carbon nano-onions by pyrolisys of propane

2013

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“…Significantly more ordered and more curved carbon layers of shells were seen in this study than in premixed benzene combustion [99]. Diameter (nm) Arc Length (nm)…”

Section: Fullerenesmentioning

confidence: 48%

“…These studies all used high resolution transmission electron microscopy (HRTEM) images to perform a qualitative analysis of the evolution of nanostructures in flames while Grieco [37,99] also performed a quantitative analysis. It was observed that nanostructures are formed in fullerene-forming flames and that the amount of closed-shell structures and fullerenic material increases with residence time, or distance from the burner.…”

Section: Nanostructureformation Inflamesmentioning

confidence: 99%

“…It was observed that nanostructures are formed in fullerene-forming flames and that the amount of closed-shell structures and fullerenic material increases with residence time, or distance from the burner. These HRTEM images show that soot becomes more ordered farther from the burner [37,90,91,99]. The premixed study also found that nanostructures require a much longer residence time to form than do fullerenes [37].…”

Section: Nanostructureformation Inflamesmentioning

confidence: 99%

“…The technique used for quantitative analysis of the TEM images, which has been described previously [37,99], allows for the quantification of radius, length, and curvature of observed carbon structures within the soot material. …”

Section: Quantitative Analysismentioning

confidence: 99%

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Combustion synthesis of fullerenes and fullerenic nanostructures

Goel

Hebgen

Sande

et al. 2002

Carbon

Self Cite

117

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Fullerenes are molecules comprised entirely of sp 2 -bonded carbon atoms arranged in pentagonal and hexagonal rings to form a hollow, closed-cage structure. Buckyballs, a subset which contains C 60 and C 70 , are single-shell molecules while fullerenic nanostructures can contain many shells and over 300 carbon atoms. Both fullerenes and nanostructures have an array of applications in a wide variety of fields, including medical and consumer products. Fullerenes were discovered in 1985 and were first isolated from the products of a laminar low-pressure premixed benzene/oxygen/argon flame operating at fuel-rich conditions in 1991. Flame studies indicated that fullerene yields depend on operating parameters such as temperature, pressure, residence time, and equivalence ratio. High-resolution transmission electron microscopy (HRTEM) showed that the soot contains nanostructures, including onions and nanotubes.Although flame conditions for forming fullerenes have been identified, the process has not been optimized and many flame environments of potential interest are unstudied. Mechanistic characteristics of fullerene formation remain poorly understood and cost estimation of large-scale production has not been performed. Accordingly, this work focused on: 1) studying fullerene formation in diffusion and premixed flames under new conditions to identify optimal parameters; 2) investigating the reaction of fullerenes with soot; 3) positively identifying C 60 molecules in HRTEM by tethering them to carbon black; and 4) providing a cost estimation for industrial fullerenic soot production.Samples of condensable material from laminar low-pressure benzene/argon/oxygen diffusion flames were collected and analyzed by high-performance liquid chromatography (HPLC) and HRTEM. The highest concentration of fullerenes in a flame was always detected just above the height where the fuel is consumed. The percentage of fullerenes in condensable material increases with decreasing pressure and the fullerene content of flames with similar cold gas velocities shows a strong dependence on length. A shorter flame, resulting from higher dilution or lower pressure, favors the formation of fullerenes rather than soot, exhibited by the lower amount of soot and precursors in such flames. This indicates a stronger correlation of fullerene consumption to soot levels than of fullerene formation to precursor concentration. The maximum flame temperature seems to be of minor importance in formation. The overall highest amount of fullerenes was found for a surprisingly high dilution of fuel with argon. The HRTEM analysis showed an increase of the curvature of the carbon layers, and hence increased fullerenic character, with increasing distance from the burner up to the point of maximum fullerene concentration, after which it decreases, consistent with the HPLC analysis. The soot shows highly ordered regions that appear to have been cells of fullerenic nanostructure formation. The samples also included fullerenic nanostructures such as tubes and sp...

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Nucleation and Growth of Closed Many-Layer Carbon Particles

Berezkin

2001

phys. stat. sol. (b)

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A new model of a structure of closed many-layer carbon particles, their origin and growth is proposed. The model is that single-layer fullerenes being the minimum possible closed particles are nuclei of bigger particles. With structural defects fullerenes take a role of a physical surface on which the carbon concentric layers in the form of deformed and defective carbon networks are deposited. Microcrystallites as areas of coherent X-ray scattering are the flattest regions of several outer particle layers. Experimental data that can justify the model are analyzed. The theoretical expressions for rates and times of the particle growth are obtained. A number of quantitative estimates is made. Possible mechanisms of the particle growth are discussed. It is marked that the process of the particle formation as a gas-solid state phase transition in some features is similar to the crystalline growth from a gas phase. At the same time there are specific features which also are discussed.

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Fullerenic carbon in combustion-generated soot

Cited by 163 publications

References 36 publications

Method to obtain carbon nano-onions by pyrolisys of propane

Method to obtain carbon nano-onions by pyrolisys of propane

Combustion synthesis of fullerenes and fullerenic nanostructures

Nucleation and Growth of Closed Many-Layer Carbon Particles

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