X-ray scattering study of the average polycyclic aromatic unit in Ledo coal

Boruah, R. K.; Saikia, Binoy K.; Baruah, Bimala P.; Dey, Nibaran C.

doi:10.1107/s0021889807049655

Cited by 24 publications

(11 citation statements)

References 33 publications

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“…Information on interlayer spacing, stacking height, and distance between crystallite units can be investigated by XRD with a careful assignment of the peak positions, fwhm values, and intensities of the diffraction peaks. , Figure shows the XRD curves with peak characteristics for the six coal samples. The peak (002) is located at 2θ equal to 25° reflection and is called the π band, and the (10) band was near 40° .…”

Section: Resultsmentioning

confidence: 99%

Characterization of the Chemical Structure of Tectonically Deformed Coals

Jiang

Moore

et al. 2017

Energy Fuels

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Tectonic deformation damages the macromolecular structures of coal. No evidence can be found of tectonically deformed coal (TDC) structures, in which traces of lattice defects exist. In this study, the mechanisms of ductile deformation and the evolution of the molecular structure have been investigated using coal samples collected from one thrust fault in the Qinan Coal Mine of China. Various characterization methods, such as Raman spectroscopy (Raman), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and nuclear magnetic resonance (NMR) imaging, were employed to explore the macromolecular structure parameters and related information that can be derived from coal subjected to ductile deformation. The results show that the full width at half maximum (fwhm parameter) for D1 of ductile deformation coal is greater than that of brittle deformation coal as a result of its high content of defects in the graphitic structure. The difference in the ratio of the −CH 2 − and −CH 3 functional groups indicates that coals that undergo brittle deformation have a much higher content of aliphatic chains compared to coals that undergo ductile deformation. Defects may result from the breaking of CO bonds in coal macromolecules, given that the maximum energy of broken CO bonds is less. Hence, the content of CO functional groups is less in TDCs than in primary structure coals. Evidently, high shearing stress leads to strong ductile deformation, while brittle deformation is related to the breaking of a series of bonds as a result of tensile stress and direct bond breakage. Ductile deformation, which is more likely to be related to point and line defects, leads to the assessed changes in the carbon structure.

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Section: Resultsmentioning

confidence: 99%

Characterization of the Chemical Structure of Tectonically Deformed Coals

Jiang

Moore

et al. 2017

Energy Fuels

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“…19−21 Coal has an intermediate crystalline structure between amorphous carbon and graphitic state referred to as "turbostratic structure". 22 Besides this crystalline structure, coal also has the amorphous form of nonaromatic carbon because of the presence of defective structured material. The polyaromatic framework in coal is similar to graphene's sp 2 hybridization properties.…”

Section: Coal-derived Activated Carbon For Electrochemical Energy Sto...mentioning

confidence: 99%

“…Coal is termed as primarily brown or black solid carbon-rich fossil fuels formed from algal remains or spores and the decomposition of humic coal, stratified sedimentary and higher plants . It is not only a source of energy but also an abundant natural resource for synthesizing carbonaceous materials. − Coal has an intermediate crystalline structure between amorphous carbon and graphitic state referred to as “turbostratic structure” . Besides this crystalline structure, coal also has the amorphous form of nonaromatic carbon because of the presence of defective structured material.…”

Section: Coal-derived Activated Carbon For Electrochemical Energy Sto...mentioning

confidence: 99%

Coal-Derived Activated Carbon for Electrochemical Energy Storage: Status on Supercapacitor, Li-Ion Battery, and Li–S Battery Applications

2021

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In this era of exponential growth in energy demand and its adverse effect on global warming, electrochemical energy storage systems have been a hot pursuit in both the scientific and industrial communities. In this regard, supercapacitors, Li-ion batteries, and Li–S batteries have evolved as the most plausible storage systems with excellent commercial adaptations. Intending to get the best performance from these systems, researchers all over the world have been engaging to develop various new methods for the synthesis of advanced carbon materials with a target of economical viability, abundance, low cost, and ease of preparation. Among them, activated carbon has proven to be an attractive electrode material due to its many advantageous properties such as a large surface area, high pore density, good conductivity, low cost, and good mechanical and chemical stability compared to other alternatives, such as high-cost graphene, carbon nanotubes, Mxenes, transition metal complexes, and conducting polymers. Among the numerous synthetic and biological resources that are used for the synthesis of activated carbon, coal/coal-like materials have found tremendous importance in recent times due to their relative abundance, extremely low cost, and excellent large-scale production possibilities. The present review attempts to collect all the significant innovations carried out for the use of cheap and economically viable coal-derived/-based activated carbon and its composites in supercapacitors, Li-ion batteries, and Li–S batteries and to critically evaluate their comparative performances. The progress in advanced three-dimensional printing technology for these energy storage applications is also discussed. The highlight of this review is also to assess the challenges that remain for the synthesis of high-performance electroactive-activated carbon materials from coal-based resources as alternative electrode materials, which would become promising candidates in the foreseeable future.

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“…The low-quality Northeast Indian coals were reported to have graphite-like polyaromatic structures. [67][68][69] The graphitic-like structure present in these coals can be broken and separated by means of chemical treatments, such as chemical oxidation. 4 The irregular and polyaromatic hydrocarbons in coal are joined by weak links and were preferentially oxidized during reuxing with HNO 3 acid in this OCE process, leading to the formation of partially ordered and defective carbon layers.…”

Section: S-6 In Esi †)mentioning

confidence: 99%