Hybrid superaggregate morphology as a result of aggregation in a cluster-dense aerosol

Dhaubhadel, Rajan; Pierce, Flint; Chakrabarti, Amitabha; Sorensen, C. M.

doi:10.1103/physreve.73.011404

Cited by 47 publications

(37 citation statements)

References 18 publications

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“…The derivation of Df and plots for all of the samples are shown in the supplementary material ( Figure S1). These values of Df are in agreement with the observations made in previous studies on nascent soot particles produced from different fuel sources [3,65]. Also for all nascent vs. denuded pairs (except for the nascent-oxidized pair: N5-D5), there is no significant change (within 1 ) in Df after thermodenuding (Figure 4).…”

Section: Resultssupporting

confidence: 91%

Effect of Thermodenuding on the Structure of Nascent Flame Soot Aggregates

et al. 2017

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Abstract:The optical properties (absorption and scattering) of soot particles depend on soot size and index of refraction, but also on the soot complex morphology and the internal mixing with materials that can condense on a freshly emitted (nascent) soot particle and coat it. This coating can affect the soot optical properties by refracting light, or by changing the soot aggregate structure. A common approach to studying the effect of coating on soot optical properties is to measure the absorption and scattering coefficients in ambient air, and then measure them again after removing the coating using a thermodenuder. In this approach, it is assumed that: (1) most of the coating material is removed; (2) charred organic coating does not add to the refractory carbon; (3) oxidation of soot is negligible; and, (4) the structure of the pre-existing soot core is left unaltered, despite the potential oxidation of the core at elevated temperatures. In this study, we investigated the validity of the last assumption, by studying the effect of thermodenuding on the morphology of nascent soot. To this end, we analyzed the morphological properties of laboratory generated nascent soot, before and after thermodenuding. Our investigation shows that there is only minor restructuring of nascent soot by thermodenuding.

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Section: Resultssupporting

confidence: 91%

Effect of Thermodenuding on the Structure of Nascent Flame Soot Aggregates

et al. 2017

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“…45 The "normal" soot produced in such flames consists of roughly spherical monomers (primary particles) with diameters in the range of 20 to 50 nm joined together into fractal aggregates. 46,47 The composition of these monomers is typically mostly carbon with a carbon/hydrogen ratio of C/H ≈ 8, and the carbon is nearly amorphous being composed of many small graphitic planes. 45 In strong contrast detonation carbon is pure carbon with graphene morphology and characteristics; it is graphene.…”

Section: Resultsmentioning

confidence: 99%

One-step synthesis of graphene via catalyst-free gas-phase hydrocarbon detonation

et al. 2013

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A one-step, gas-phase, catalyst-free detonation of hydrocarbon (C2H2) method was developed to produce gram quantities of pristine graphene nanosheets (GNs). The detonation of C2H2 was carried out in the presence of O2. The molar ratios of O2/C2H2 were 0.4, 0.5, 0.6, 0.7 and 0.8. The obtained GNs were analyzed by XRD, TEM, XPS and Raman spectroscopy. The GNs are crystalline with a (002) peak centered at 26.05° (d = 0.341 nm). TEM shows that the GNs are stacked in two to three layers and sometimes single layers. An increase in the size of the GNs (35–250 nm) along with a reduction in defects (Raman ID/IG ∼ 1.33–0.28) and specific surface area (187–23 m2 g−1) was found with increasing O2 content. The high temperature of the detonation, ca. 4000 K, is proposed as the cause of graphene production rather than normal soot. The method allows for the control of the number of layers, shape and size of the graphene nanosheets. The process can be scaled up for industrial production.

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“…In the case of the carbon aerosol gel the initial aerosol is composed of nanometer sized carbon particles produced rapidly by exploding any one of a number of hydrocarbons with oxygen in a closed chamber. These nanometer sized carbon particles quickly aggregate and then gel to form the aerosol gel (Dhaubhadel et al 2006). Unlike conventional aerogels this method of making an aerosol gel is not a wet process and does not require a catalyst.…”

Section: Introductionmentioning

confidence: 99%

Aerosol Gelation: Synthesis of a Novel, Lightweight, High Specific Surface Area Material

Dhaubhadel

Gerving

Sorensen

2007

Aerosol Science and Technology

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We demonstrate that an aerosol can gel. This gelation is then used for a one-step method to produce an ultralow density porous carbon material. This material is named an aerosol gel because it is made via gelation of particles in the aerosol phase. The carbon aerosol gels have high specific surface area (200-350 m 2 /g), an extremely low density (2.5-5.0 mg/cc) and a high electrical conductivity, properties similar to conventional aerogels. The primary particles of the carbon aerosol gels are highly crystalline with a narrow (002) graphitic X-ray diffraction peak. Key aspects to form a gel from an aerosol are large volume fraction, ca. 10 −4 or greater, and small primary particle size, 50 nm or smaller, so that the gel time is fast compared to other characteristic times.

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Hybrid superaggregate morphology as a result of aggregation in a cluster-dense aerosol

Cited by 47 publications

References 18 publications

Effect of Thermodenuding on the Structure of Nascent Flame Soot Aggregates

Effect of Thermodenuding on the Structure of Nascent Flame Soot Aggregates

One-step synthesis of graphene via catalyst-free gas-phase hydrocarbon detonation

Aerosol Gelation: Synthesis of a Novel, Lightweight, High Specific Surface Area Material

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