Transformation of graphene nanoflakes into onion-like carbon during spark plasma sintering

Suslova, E. V.; Epishev, Vsevolod; Маслаков, К. И.; Максимов, С. В.; Savilov, S. V.

doi:10.1016/j.apsusc.2020.147724

Cited by 12 publications

(7 citation statements)

References 41 publications

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“…SPS was performed on a Labox-625 (Sinterland, Nagaoka City, Japan) apparatus at 1000–1100 °C for 5 min under the axial pressure of 22–30 MPa in a vacuum of 10 −2 torr as described in [ 26 , 34 ]. Linear shrinkage of the specimen during SPS was continuously monitored.…”

Section: Methodsmentioning

confidence: 99%

“…CNTs_SPS was oxidized with HNO 3 vapors according to the procedure described in [ 25 , 26 ]. For this purpose, a pellet was placed in an open box with boiling HNO 3 for 3 or 6 h. The oxidized samples were named as CNTs_SPS_x where x = 3, 6 is the oxidation time in hours.…”

Section: Methodsmentioning

confidence: 99%

“…CNM oxidation with liquid HNO 3 [ 24 ] or its vapors [ 25 , 26 ] increases acidity and defect density on the carbon surface. Gas phase oxidation is a more convenient oxidation route because it eliminates filtration, washing and drying steps.…”

Section: Introductionmentioning

confidence: 99%

“…Gas phase oxidation is a more convenient oxidation route because it eliminates filtration, washing and drying steps. Moreover, the oxidation in the gas-phase can be considered as a suitable method for the modification of 3D carbon materials consolidated by spark plasma sintering (SPS) without compromising the pellet integrity [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

“…Different CNMs were consolidated by SPS [ 26 , 27 , 28 ]. Consolidated CNMs can be used as adsorbents [ 29 ], biocompatible materials [ 30 ], catalysts, catalysts supports [ 31 ] and electrodes in energy storage devices [ 32 ].…”

Section: Introductionmentioning

confidence: 99%

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Conversion of Secondary C3-C4 Aliphatic Alcohols on Carbon Nanotubes Consolidated by Spark Plasma Sintering

et al. 2021

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We analyze how the changes in the dimension of carbon nanomaterial (CNM) affect their catalytic conversion of secondary aliphatic alcohols. Carbon nanotubes (CNTs) consolidated by spark plasma sintering (SPS) were inactive in the conversion of secondary C3-C4 aliphatic alcohols because of the «healing» of defects in carbon structure during SPS. Gas-phase treatment of consolidated CNTs with HNO3 vapors led to their surface oxidation without destruction of the bulk structure of pellets. The oxygen content in consolidated CNTs determined by X-ray photoelectron spectroscopy increased from 11.3 to 14.9 at. % with increasing the oxidation time from 3 to 6 h. Despite the decrease in the specific surface area, the oxidized samples showed enhanced catalytic activity in alcohol conversion because of the increased number of oxygen radicals with unpaired electrons, which was established by electron paramagnetic resonance spectroscopy. We conclude that the structure of CNM determines the content and/or ratio of sp2 and sp3-hybridized carbon atoms in the material. The experimental and literature data demonstrated that sp3-hybridized carbon atoms on the surface are probably the preferable site for catalytic conversion of alcohols.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%