Pressure-Induced Transformation of Graphite and Diamond to Onions

Бланк, В. Д.; Churkin, Valentin; Kulnitskiy, B.A.; Perezhogin, I. A.; Кириченко, А. Н.; Erohin, Sergey V.; Сорокин, Павел Б.; Popov, M.

doi:10.3390/cryst8020068

Cited by 23 publications

(22 citation statements)

References 27 publications

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“…On the contrary, the disordered structure of graphite has the presence of additional first-order bands (D-bands) at 1360 and 1620 cm −1 depending on the ambient conditions 28 . The bands in the region of 2800-3500 cm −1 could also correspond to the combinational models of D and G-bands 26,27 . The signals of the graphite and soot are hard to distinguish, however, there is evidence that the soot itself has broader peaks 27,28 .…”

Section: Resultsmentioning

confidence: 79%

“…The bands in the region of 2800-3500 cm −1 could also correspond to the combinational models of D and G-bands 26,27 . The signals of the graphite and soot are hard to distinguish, however, there is evidence that the soot itself has broader peaks 27,28 . The spectra of propane under pressure of 3 GPa and at an ambient temperature of 900 K (±100 K) show no major changes in the display of any of the bands that are typical for propane 16 .…”

Section: Resultsmentioning

confidence: 79%

“…This material has very similar Raman spectra to the typical black solid compound obtained during the thermal and catalytic petrochemical processes or as a by-product of combustion according to the reaction: = + C H 3C 4H 3 8 2 During such processes, there is also the possibility of obtaining a graphite, which could be either disordered or highly ordered. However, the character of the presented spectra of the propane reaction products indicates the presence of disordered phases of graphite or soot 27 . The highly ordered Raman spectra of graphite exhibits only one band (first-order G-bands) at 1580 cm −1 at ambient temperature.…”

Section: Resultsmentioning

confidence: 92%

“…Propane is heavier than methane by mass, and thus propane can easier decompose and produce larger number of hydrocarbon compounds. [2][3][4]12 , for unsaturated hydrocarbons, they were obtained from 30,32 , and for graphite (soot) modes, they were taken from 27,28 . The strong fluorescence in the region of the hydrocarbon footprint is explained by the presence of complex hydrocarbon systems of mixed structure.…”

Section: Figurementioning

confidence: 99%

“…For example, the hydrogen generation in our case could be explained not only by thermal decomposition of hydrocarbons, but by the catalytic effect of the carbon in the form of graphite or soot 35,36 . 11 and 14 GPa. The reference peaks for C-H valence of saturated hydrocarbon compounds were obtained from [2][3][4]12 , for unsaturated hydrocarbons from 31,32 , for graphite (soot) modes, they were obtained from 27,28 . The reference peaks for C-C stretching and C-C bending of hydrocarbons were obtained for ethane from 12 , for propane from 12,37 , for n-butane from 12,37 , for n-pentane from 38 , and for n-hexane from 38 .…”

Section: Scientific Reports |mentioning

confidence: 99%

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Raman Spectroscopy Study on Chemical Transformations of Propane at High Temperatures and High Pressures

Kudryavtsev

Fedotenko

Koemets

et al. 2020

Sci Rep

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this study is devoted to the detailed in situ Raman spectroscopy investigation of propane c 3 H 8 in laserheated diamond anvil cells in the range of pressures from 3 to 22 GPa and temperatures from 900 to 3000 K. We show that propane, while being exposed to particular thermobaric conditions, could react, leading to the formation of hydrocarbons, both saturated and unsaturated as well as soot. Our results suggest that propane could be a precursor of heavy hydrocarbons and will produce more than just sooty material when subjected to extreme conditions. These results could clarify the issue of the presence of heavy hydrocarbons in the earth's upper mantle.Thermal and catalytic transformations of various hydrocarbon compounds at normal pressure have attracted significant attention in the field of petrochemistry. However, high-pressure chemistry of hydrocarbons as a science started to develop only recently, -primarily due to the unavailability of the specific equipment for the experiments. To date, only methane, the first member of the alkane homologous series, has been investigated when subjected to a wide range of pressures and temperatures 1-4 , because of its widespread occurrence in geological systems 5-7 and well-known role in the atmosphere of the Solar System's outer planets 8,9 . The behavior of other hydrocarbons, both unsaturated 10,11 and saturated 12,13 , have been less widely investigated with the use of various high-pressure techniques.The focus on the significance of methane's high-pressure high-temperature behavior implies that the fate of higher hydrocarbons has been ignored. Though the high-pressure, high-temperature (HPHT) behavior of ethane has been investigated several times 12,14 , propane has only been studied at ambient temperatures 15,16 . Propane is the third most abundant hydrocarbon on Earth after methane and ethane. It has been detected in the atmosphere of outer planets 17 and their satellites 18 , and is a typical product of HPHT hydrocarbon synthesis performed both for chemical and geological purposes 19,20 .The relevance of the investigation of carbon-bearing compounds can be understood from the perspective of the growing evidence of the role of hydrocarbon compounds deep in the Earth's interior, which could contribute to the global carbon cycle 21,22 . Unfortunately, even for methane, investigations into its behavior under conditions of high pressure have yielded inconclusive and mutually conflicting results.Propane's importance as a petrochemical feedstock led to detailed studies of its thermal transformations in the range of 500-900 °C in processes such as pyrolysis and thermal cracking [23][24][25] . By changing the basic conditions of the process, the content of hydrocarbon compounds complex systems could be varied from higher normal and isoalkanes, dienes, arenes, and alkenes to C 1 -C 3 fractions. These thermal processes were only investigated in the diapason under relatively mild pressures because of the process goal-low pressures are favorable for the synthesis of low-molecul...

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Section: Resultsmentioning

confidence: 79%

Section: Resultsmentioning

confidence: 79%

Section: Resultsmentioning

confidence: 92%

Section: Figurementioning

confidence: 99%

Section: Scientific Reports |mentioning

confidence: 99%

See 3 more Smart Citations

Raman Spectroscopy Study on Chemical Transformations of Propane at High Temperatures and High Pressures

Kudryavtsev

Fedotenko

Koemets

et al. 2020

Sci Rep

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Review on Recent Advancements in Severe Plastic Deformation of Oxides by High‐Pressure Torsion (HPT)

Edalati

2018

Adv Eng Mater

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Severe plastic deformation (SPD) of oxides has been of interest in mineralogy and geology for many decades, but oxides have ionic or covalent bonds with brittle nature and can hardly be deformed at ambient temperature. SPD processing of oxides is first realized in 1930s, when Percy W. Bridgman introduce the principles of high-pressure torsion (HPT) method. Although the method is widely used nowadays to produce ultrafine-grained (UFG) metals, the application of method for SPD processing of oxides is quite limited. This article reviews some of the recent publications on the application of HPT method to oxide ceramics () and summarizes their major findings: powder compaction and partial consolidation, nanograin formation, formation of different kinds of lattice defects such as dislocations and oxygen vacancies, strain and grain size dependence of phase transformations, and improvement of functional properties such as bandgap narrowing, photoluminescence, photocatalytic activity, and dielectricity. Early Studies on HPT Processing of OxidesAs mentioned earlier, SPD processing of oxides has been of interest for many decades in mineralogy and geology. Boeker is

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Phase Transformations in MgH₂–TiH₂ Hydrogen Storage System by High‐Pressure Torsion Process

Kitabayashi

Edalati

et al. 2019

Adv Eng Mater

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Magnesium hydride (MgH2) and titanium hydride (TiH2) are two potential candidates for solid‐state hydrogen storage, but strong hydride formation energy in these hydrides undesirably results in their high dehydrogenation temperature. First‐principles calculations show that the metastable hydrides in the MgH2–TiH2 system have low hydrogen binding energy, which makes them more appropriate for low‐temperature hydrogen storage. In this study, severe plastic deformation (SPD) via the high‐pressure torsion (HPT) method is applied to the MgH2–TiH2 system to synthesize metastable hydrides. While MgH2 transforms to a high‐pressure orthorhombic γ phase, TiH2 does not exhibit any cubic‐to‐tetragonal phase transformation even by HPT processing at cryogenic temperature. Application of large strains by 400 HPT turns to the immiscible MgH2/TiH2 composite results in atomic‐scale mixing and formation of nanostructured ternary Mg–Ti–H hydride with the metastable FCC structure and lower dehydrogenation temperature than TiH2.

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Pressure-Induced Transformation of Graphite and Diamond to Onions

Cited by 23 publications

References 27 publications

Raman Spectroscopy Study on Chemical Transformations of Propane at High Temperatures and High Pressures

Raman Spectroscopy Study on Chemical Transformations of Propane at High Temperatures and High Pressures

Review on Recent Advancements in Severe Plastic Deformation of Oxides by High‐Pressure Torsion (HPT)

Phase Transformations in MgH₂–TiH₂ Hydrogen Storage System by High‐Pressure Torsion Process

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Pressure-Induced Transformation of Graphite and Diamond to Onions

Cited by 23 publications

References 27 publications

Raman Spectroscopy Study on Chemical Transformations of Propane at High Temperatures and High Pressures

Raman Spectroscopy Study on Chemical Transformations of Propane at High Temperatures and High Pressures

Review on Recent Advancements in Severe Plastic Deformation of Oxides by High‐Pressure Torsion (HPT)

Phase Transformations in MgH2–TiH2 Hydrogen Storage System by High‐Pressure Torsion Process

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Phase Transformations in MgH₂–TiH₂ Hydrogen Storage System by High‐Pressure Torsion Process