Electrochemical Synthesis and Thermal Properties of Graphite Bisulfate

Leshin, V. S.; Сорокина, Н. Е.; Авдеев, В. В.

doi:10.1023/b:inma.0000032001.86743.00

Cited by 11 publications

(4 citation statements)

References 4 publications

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“…The aim was to gain a better understanding of the true nature of expandable graphite grades used in industry. Finally, this communication complements previous studies that have investigated the thermal properties of graphite bisulphate [11,31].…”

Section: Graphite Intercalation Compounds (Gics) Possess Guest Molecusupporting

confidence: 77%

“…The composition of the Stage 1 compound is stated as C 24 + ·HSO 4 -·2H 2 SO 4 [11,12]. Graphite bisulfate may be produced electrochemically [11] or by dipping natural graphite in concentrated sulfuric acid with sufficient nitric acid to oxidise the graphite to prepare it for intercalation [9].…”

Section: Graphite Intercalation Compounds (Gics) Possess Guest Molecumentioning

confidence: 99%

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Characterization of commercial expandable graphite fire retardants

et al. 2014

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Thermal analysis and other techniques were employed to characterize two expandable graphite samples. The expansion onset temperatures of the expandable graphite's were ca.220°C and 300°C respectively. The key finding is that the commercial products are not just pure graphite intercalation compounds with sulfuric acid species intercalated as guest ions and molecules in between intact graphene layers. A more realistic model is proposed where graphite oxide-like layers are also randomly interstratified in the graphite flakes. These graphite oxide-like layers comprise highly oxidized graphene sheets which contain many different oxygen-containing functional groups. This model explains the high oxygen to sulfur atomic ratios found in both elemental analysis of the neat materials and in the gas generated during the main exfoliation event.

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Section: Graphite Intercalation Compounds (Gics) Possess Guest Molecusupporting

confidence: 77%

Section: Graphite Intercalation Compounds (Gics) Possess Guest Molecumentioning

confidence: 99%

Characterization of commercial expandable graphite fire retardants

et al. 2014

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“…To prepare [HSO 4 ] – intercalation compounds, most commonly, graphite is treated with an excess of concentrated sulfuric acid and oxidizing agents to provoke intercalation. Depending on the concentration of the acid and its acidity in combination with the potential of the oxidant, different stages can be obtained 5a–5h. In a stage 1 compound a graphite layer alternates with a host interlayer, in a stage 2 compound two graphite layers alternate with a host interlayer and so on.…”

Section: Introductionmentioning

confidence: 99%

Gas‐phase Preparation of SO₃‐Graphite: Host‐Exchange and Exfoliation

Feicht

Breu

2015

Zeitschrift anorg allge chemie

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The reaction of sulfur trioxide with graphite via gas phase led to an intercalation of a double layer of sulfur trioxide with a basal spacing of 11.1 Å. The SO3‐graphite was obtained atom‐efficient as a single phase product without the need of purification. The increased basal space should facilitate an exfoliation by rendering the tactoids more shear labile. A further weakening of the attractive forces within a stack was done by the replacement of sulfur trioxide with the surfactant perfluorobutanesulfonic acid leading to a basal spacing of 16.8 Å. The large basal spacings were also preserved in suspension and no defects were created. The mechanical exfoliation with ultrasound predominantly broke the platelets. A rotor‐stator device offering high shear forces was found to exfoliate the platelets more gently but there was still a good number of very small particles.

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“…The presence of chromium in the sample makes it possible to suggest that K 2 Cr 2 O 7 was used as an oxidizer for synthesis. According to data on thermal analysis, the DSC peak attributed to the decomposition of GICs (graphite bisulfate) is exothermic, whereas some studies [37,38] reported that it had an endothermic nature. An exothermic DSC peak appearing as a result of graphite bisulfate decomposition was also found in [39].…”

Section: Resultsmentioning

confidence: 99%

Highly Porous Expanded Graphite: Thermal Shock vs. Programmable Heating

et al. 2021

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Highly porous expanded graphite was synthesized by the programmable heating technique using heating with a constant rate (20 °C/min) from room temperature to 400–700 °C. The samples obtained were analyzed by scanning electron microscopy, energy-dispersive spectroscopy, low-temperature nitrogen adsorption, X-ray photoelectron spectroscopy, Raman spectroscopy, thermogravimetry, and differential scanning calorimetry. A comparison between programmable heating and thermal shock as methods of producing expanded graphite showed efficiency of the first one at a temperature 400 °C, and the surface area reached 699 and 184 m2/g, respectively. The proposed technique made it possible to obtain a relatively higher yield of expanded graphite (78–90%) from intercalated graphite. The experiments showed the advantages of programmable heating in terms of its flexibility and the possibility to manage the textural properties, yield, disorder degree, and bulk density of expanded graphite.

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Electrochemical Synthesis and Thermal Properties of Graphite Bisulfate

Cited by 11 publications

References 4 publications

Characterization of commercial expandable graphite fire retardants

Characterization of commercial expandable graphite fire retardants

Gas‐phase Preparation of SO₃‐Graphite: Host‐Exchange and Exfoliation

Highly Porous Expanded Graphite: Thermal Shock vs. Programmable Heating

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Electrochemical Synthesis and Thermal Properties of Graphite Bisulfate

Cited by 11 publications

References 4 publications

Characterization of commercial expandable graphite fire retardants

Characterization of commercial expandable graphite fire retardants

Gas‐phase Preparation of SO3‐Graphite: Host‐Exchange and Exfoliation

Highly Porous Expanded Graphite: Thermal Shock vs. Programmable Heating

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Product

Resources

About

Gas‐phase Preparation of SO₃‐Graphite: Host‐Exchange and Exfoliation