Oxidative Reactivity of Particulate Samples from Different Diesel Combustion Systems and Its Relation to Structural and Spectral Characteristics of Soot

Zygogianni, Alexandra; Syrigou, Maria; Konstandopoulos, Athanasios G.; Kostoglou, Margaritis

doi:10.1007/s40825-019-00118-1

Cited by 15 publications

(2 citation statements)

References 43 publications

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“…Since carbon is the main constituent in the material, it is not surprising that Raman spectroscopy is a widely used method for the characterization of any type of soot [3,5,6,8,12,13,[34][35][36][37][38][39][40][41][42].…”

Section: Raman Spectroscopy Investigationmentioning

confidence: 99%

Transforming Chimney Soot via Stochastic Polymerization for Active Electrode Coating

et al. 2023

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A polymerization procedure is presented to increase the molecular weight of hydrocarbons in household chimney soot without thermal treatment at high temperatures. Pristine soot was subject to chlorination, with half of it treated with magnesium (Mg-plates) to create random-type Grignard reagents (R-Mg-Cl) in diethyl ether media. Mixing the Grignard reagent and the rest of the halogenated soot material created new C-C bonds, thus increasing the molecular weight of the final product. The obtained stochastically polymerized soot (SPS) was investigated using Raman spectroscopy, FTIR spectroscopy and XPS and was subjected to electrochemical testing as an assembled supercapacitor with a KOH electrolyte. Results show significant carbon structure differences due to the chemical procedures and newly created functional groups in the soot. Such functional groups could increase the capacity of supercapacitors, creating pseudo-capacitance by participating in redox reactions. The results also unveiled removing any random contaminations in the pristine soot and obtaining a more uniform final product containing hydrocarbons with longer chains, thus increasing the molecular weight.

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Section: Raman Spectroscopy Investigationmentioning

confidence: 99%

Transforming Chimney Soot via Stochastic Polymerization for Active Electrode Coating

et al. 2023

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“…As discussed above in the previous section, the d Q /d V plots for the pristine and hybrid have broad peaks at identical potentials. Ex situ Raman spectra of the cathode composites both uncycled and cycled (Figure C,D) show the presence of elemental sulfur (at 151, 218, 245, and 473.5 cm –1 ), carbon (1340 cm –1 ), and small amounts of LPSCl (426.5 cm –1 ). In the cycled pristine and hybrid composites a small signal for Li 2 S 2 is evident at 442 cm –1 (Figure D, open squares) .…”

mentioning

confidence: 99%

Toward High-Capacity Li–S Solid-State Batteries: The Role of Partial Ionic Transport in the Catholyte

Woolley,

Lange,

Nazmutdinova

et al. 2024

ACS Energy Lett.

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To address the challenges of tortuous partial ionic transport and chemomechanical failure due to the large volumetric changes of sulfur during all-solid-state battery cycling, we evaluate a hybrid electrolyte composed of the lithium chloride argyrodite Li 6 PS 5 Cl (LPSCl) and an ionic liquid-based lithium liquid electrolyte (ILE) in the cathode composite of Li−S half-cells. We confirm the stability of the LPSCl/ILE interface by coupling Raman and impedance spectroscopy measurements. Charge−discharge curves show a capacity improvement for the hybrid cells (1364 ± 151 mAh•g −1 ), compared to 904 ± 186 mAh•g −1 for pristine cells. Transport measurements quantify an increase in the partial ionic conductivity of proxy cathode layers from 0.2 to 0.4 mS•cm −1 in hybrid cells. Taken together, the use of the ILE increases the partial ionic transport and access to sulfur which results in higher and more stable discharge capacities.

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Influence of Global Operating Parameters on the Reactivity of Soot Particles from Direct Injection Gasoline Engines

Koch

Hagen

Büttner

et al. 2022

Emiss. Control Sci. Technol.

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The aim of this study is to investigate the impact of global operating parameters, e.g., engine speed, brake mean effective pressure, and air–fuel ratio, of a turbocharged 4-cylinder GDI engine on the reactivity of soot particles against oxidation. The knowledge of soot reactivity is crucial for optimizing gasoline particulate filter regeneration strategies and is, consequently, a key parameter for reducing fuel consumption and CO2 emissions. In this work, time-resolved in-cylinder soot concentrations and exhaust particle size distributions are measured by using two-color pyrometry, engine exhaust particle sizer and smoke meter, respectively. Reactivity against oxidation by molecular oxygen is determined by temperature programmed oxidation analysis. To derive a physicochemical explanation for varying soot reactivity, the morphological and nanostructural primary particle structure of collected samples is analyzed using high-resolution electron microscopy and image analysis algorithms. The results reveal that engine operating parameters affect soot reactivity differently. While engine speed has only a slight effect, a reduction of air/fuel ratio (λ < 1.0) or an increase of BMEP > 10 bar significantly reduces the soot oxidation reactivity. These findings give evidence, that the quality of the fuel/air mixture is a significant parameter influencing soot reactivity. Measured soot concentrations substantiate the hypothesis that low-sooty homogeneous premixed combustion of a homogeneous fuel/air mixture favors formation of high-reactive soot particle fractions. Reactive soot particle aggregates are composed of multiple soot fractions of different reactivity. Reactive primary particles are composed of short graphene-like layers and vice versa, providing a physicochemical explanation for varying soot reactivity depending on engine operating conditions.

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Oxidative Reactivity of Particulate Samples from Different Diesel Combustion Systems and Its Relation to Structural and Spectral Characteristics of Soot

Cited by 15 publications

References 43 publications

Transforming Chimney Soot via Stochastic Polymerization for Active Electrode Coating

Transforming Chimney Soot via Stochastic Polymerization for Active Electrode Coating

Toward High-Capacity Li–S Solid-State Batteries: The Role of Partial Ionic Transport in the Catholyte

Influence of Global Operating Parameters on the Reactivity of Soot Particles from Direct Injection Gasoline Engines

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