Towards a kerogen-to-graphite kinetic model by means of Raman spectroscopy

Schito, Andrea; Muirhead, David; Parnell, John

doi:10.1016/j.earscirev.2022.104292

Cited by 15 publications

(5 citation statements)

References 133 publications

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“…The area ratio of two characteristic peaks can be used to measure the degree of graphitization (A D /A G ) of carbon material. 28 According to the fitting result, the A D /A G values of LMFP-1, LMFP-2, LMFP-3, and LMFP-4 samples are 2.15, 2.16, 2.15, and 2.17, respectively, indicating that the hydrogen plasma concentration has little influence on the graphitization degree of the coated carbon. Besides, a small peak exists on the left side of the figure at about 945 cm −1 , which is generated by the symmetric telescoping vibrations of phosphorus and oxygen in PO 4 3− .…”

Section: Methodsmentioning

confidence: 92%

The Effect of Oxygen Vacancy Defects on the Structure and Electrochemical Behaviors of LiMn_0.65Fe_0.35PO₄ Cathode

Zhang,

Ke,

Wang

et al. 2024

J. Electrochem. Soc.

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The presence of oxygen vacancy defects significantly impacts the crystal structure and electrochemical attributes of phosphate cathodes. In this investigation, LiMn0.65Fe0.35PO4 materials with varying levels of oxygen vacancy defects were synthesized via hydrogen plasma-induced reduction. It was observed that the content of oxygen vacancy defects on the crystal surface increased proportionately with the rise in hydrogen (H2) flow rate. Notably, the LMFP-3 sample, prepared with an H2 flow rate of 10 mL min-1, demonstrated superior electrochemical performance, characterized by a 159.7 mAh g-1 discharge capacity at 0.1C and a remarkable 99.8% capacity retention at 5C after 200 cycles. This enhancement in electrochemical performance is attributed to the improved intrinsic conductivity of the LiMn0.65Fe0.35PO4 material due to the presence of oxygen vacancy defects. However, it is important to note that an excessively high H2 flow rate can lead to the formation of Fe2P impurities, which hinder lithium ion (Li+) diffusion. Furthermore, theoretical calculations conducted using density functional theory provide a rational explanation for the observed improvement in electronic conductivity. The introduction of oxygen vacancy defects results in a significant reduction in the Band gap, which is highly beneficial for enhancing the intrinsic conductivity of the LiMn0.65Fe0.35PO4 materials.

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Section: Methodsmentioning

confidence: 92%

The Effect of Oxygen Vacancy Defects on the Structure and Electrochemical Behaviors of LiMn_0.65Fe_0.35PO₄ Cathode

Zhang,

Ke,

Wang

et al. 2024

J. Electrochem. Soc.

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“…During the diffusion process, iodine can adsorb on the substrate surface of graphite microcrystals and provide sufficient active sites, thereby promoting the adsorption and crystallization of carbon atoms, forming bond structures between carbon atoms, and promoting the growth of graphite microcrystals. The relative intensity ratio of I D /I G is commonly used to characterize the defect density of graphite [19]. The increase in I D /I G of micro/nano-porous graphite (G400, G450 and G500) after iodine diffusion is caused by the increase in defect density in graphite due to iodine diffusion.…”

Section: Crystal Structurementioning

confidence: 99%

Diffusion Behavior of Iodine in the Micro/Nano-Porous Graphite for Nuclear Reactor at High Temperature

Qi,

Lian,

et al. 2023

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The diffusion behavior of iodine in micro/nano-porous graphite under high-temperature conditions was studied using analysis methods such as Rutherford backscattering Spectrometry, scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The results indicate that iodine diffusion leads to the Lattice Contractions in Microcrystals, a decrease in interlayer spacing, and a rise of defect density. And the reversal or repair of microstructure change was observed: the microcrystal size of the graphite increases, the interlayer spacing appears to return to the initial state, and the defect density decreases, upon diffusion of iodine out of iodine-loaded graphite. The comparative study comparing the iodine diffusion performance of nanoporous graphite (G400 and G450) between microporous graphite (G500), showed that nanoporous graphite exhibits a better barrier to the iodine diffusion. The study on the diffusion behavior of iodine in micro/nano-porous graphite holds substantial academic and engineering value for the screening, design, and performance optimization of nuclear graphite.

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“…Hackley et al, 2022;Stokes et al, 2022). Schito et al (2023) have also shown that the Raman spectra of organic matter heated quickly by contact metamorphism may differ from those of organic matter that has undergone burial diagenesis.…”

Section: Bitumen Chemistrymentioning

confidence: 99%

Petrography of Pyrobitumens in Middle – Late Jurassic Sandstones From Thermally Degraded Hydrocarbon Accumulations, East Greenland

Strogen,

Marshall,

Whitham

et al. 2023

Journal of Petroleum Geology

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A number of exhumed hydrocarbon traps have been described from the Traill Ø region of East Greenland. This study focuses on the Bjørnedal area where the distribution of bitumen has been mapped out. Bitumen staining clearly has a cross‐cutting relationship to stratigraphic units and can be shown to form distinct palaeo‐accumulations. Detailed petrographic studies show that bitumen occurs as late diagenetic phases in Middle to Late Jurassic sandstones, and is present both as both grain‐coating and pore‐filling phases. Geochemical analyses confirm that the bitumen is organic in composition and is composed largely of carbon and hydrogen. Both H/C ratios and bonds identified by FTIR behave as expected with increasing maturity measured using bitumen reflectance. Together, these results provide strong evidence that the material is pyrobitumen derived from the in situ thermal degradation of a liquid hydrocarbon precursor. On the basis of textures in transmitted and reflected light and quantitative bitumen reflectance distributions, two populations of pyrobitumen may be recognised in some samples.Two phases of Paleogene magmatism occurred in the Traill Ø region. The first late Paleocene – early Eocene phase was related to the opening of the northern North Atlantic in the earliest Eocene, and was experienced throughout East Greenland and the northwest European margin. The later magmatic phase was related to the gradual separation of the Jan Mayen microcontinent from East Greenland through the late Eocene – early Oligocene. A single pyrobitumen phase is recognised in accumulations only affected by the early magmatism, and a second phase is only observed in areas affected by both the early and later magmatism. This relationship is interpreted as evidence for a direct relationship between magmatic phases and bitumen generation. The presence of bitumen formed by the thermal degradation of liquid hydrocarbons during the later magmatic event suggests that a viable petroleum system remained active following the early magmatic event.

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Towards a kerogen-to-graphite kinetic model by means of Raman spectroscopy

Cited by 15 publications

References 133 publications

The Effect of Oxygen Vacancy Defects on the Structure and Electrochemical Behaviors of LiMn_0.65Fe_0.35PO₄ Cathode

The Effect of Oxygen Vacancy Defects on the Structure and Electrochemical Behaviors of LiMn_0.65Fe_0.35PO₄ Cathode

Diffusion Behavior of Iodine in the Micro/Nano-Porous Graphite for Nuclear Reactor at High Temperature

Petrography of Pyrobitumens in Middle – Late Jurassic Sandstones From Thermally Degraded Hydrocarbon Accumulations, East Greenland

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Towards a kerogen-to-graphite kinetic model by means of Raman spectroscopy

Cited by 15 publications

References 133 publications

The Effect of Oxygen Vacancy Defects on the Structure and Electrochemical Behaviors of LiMn0.65Fe0.35PO4 Cathode

The Effect of Oxygen Vacancy Defects on the Structure and Electrochemical Behaviors of LiMn0.65Fe0.35PO4 Cathode

Diffusion Behavior of Iodine in the Micro/Nano-Porous Graphite for Nuclear Reactor at High Temperature

Petrography of Pyrobitumens in Middle – Late Jurassic Sandstones From Thermally Degraded Hydrocarbon Accumulations, East Greenland

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The Effect of Oxygen Vacancy Defects on the Structure and Electrochemical Behaviors of LiMn_0.65Fe_0.35PO₄ Cathode

The Effect of Oxygen Vacancy Defects on the Structure and Electrochemical Behaviors of LiMn_0.65Fe_0.35PO₄ Cathode