Continuous and catalyst free synthesis of graphene sheets in thermal plasma jet

Fronczak, Maciej; Fazekas, Péter; Károly, Zoltán; Hamankiewicz, Bartosz; Bystrzejewski, M.

doi:10.1016/j.cej.2017.04.051

Cited by 32 publications

(19 citation statements)

References 60 publications

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“…This values is comparable to other non‐oxidized carbon materials, e.g. activated carbon, carbon nanotubes, graphene sheets . The presented trend is non‐linear, however, the total acidity gradually rises with an increase of nitric acid concentration.…”

Section: Resultssupporting

confidence: 81%

Carbon Fibers Obtained from Flax and Their Adsorption Performance in the Removal of Cu(II) and Co(II) from Aqueous Solutions

2018

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The systematic studies on oxidation of carbon fibers with nitric acid are presented. The carbon fibers were synthesized from the low‐cost and natural stock (flax fibers) via the controlled carbonization. The non‐oxidized and surface oxidized carbon fibers were thoroughly characterized by means of electron microscopy, FT‐IR spectroscopy, thermogravimetry, point of zero charge determination, Boehm titration and nitrogen adsorption at 77K. The second part of this work was focused on the evaluation of adsorption properties of oxidized carbon fibers and their potential in the removal of copper(II) and cobalt(II) ions from aqueous solutions. The obtained results bring a conclusion that the concentration of nitric acid is a key parameter which drives the content of oxygen surface groups, thermal stability and adsorption performance of carbon fibers. The obtained oxidized carbon fibers were found to be prospective adsorbents of CuII and CoII from aqueous solutions.

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Section: Resultssupporting

confidence: 81%

Carbon Fibers Obtained from Flax and Their Adsorption Performance in the Removal of Cu(II) and Co(II) from Aqueous Solutions

2018

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“…Even when a carbon deposit has not been reported, it may be present in the product in the amorphous state [56]. Plasma processing of various aliphatic alcohols in reducing conditions can results in graphene layers instead of well crystallized carbon structure [57][58].…”

Section: Crystallographic Phase Relationsmentioning

confidence: 99%

“…A large number of publications, including a set of our previous papers, pointed out that due to its unique properties, thermal plasma processes offer an appealing route for preparing nanosized oxide, nitride, carbide and boride ceramic nanopowders [20][21][22][23][24][25][26]. Thermal plasmas possess extremely high temperatures (up to 15,000 K in the flame), large plasma volume, high enthalpy and high concentrations of chemically reactive species, enhancing the reactivity of the precursors injected in the plasmas [27][28][29]. Besides, the typically fast cooling rate (10 4 Ks -1 ) inhibits grain growth of the small molecular clusters thus promotes the formation of nanopowder.…”

Section: Introductionmentioning

confidence: 99%

In-flight Synthesis of Nanosized ZrC Particles from Various Precursors in RF Thermal Plasma

Martiz

Károly

Bódis

et al. 2021

Period. Polytech. Chem. Eng.

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Synthesis of zirconium carbide (ZrC) powder was investigated applying a non-conventional atmospheric radiofrequency (RF) thermal plasma process. In one case, zirconium dioxide (ZrO2) was reacted with solid carbon or with methane with varying molar ratio. In the other, zirconium-propoxide (NZP), containing both constituents, was thermally decomposed in the Ar plasma. Temperature-dependent thermodynamic analysis was performed in the 500-5500 K temperature range to estimate the formation of possible equilibrium products for each reaction stoichiometry. Broad temperature range exists for the stability of solid ZrC for each explored reaction system. In accordance with this prediction, X-ray diffraction studies detected the ZrC as the major phase in all the prepared powders. The yield of particular runs ranged from 39 % to 98 %. Practically, full conversion was typical for the case of NZP precursor, however only partial conversion could be detected in ZrO2 reactions. The average particle size of the powders falls between 10 nm and 100 nm depending on the type of the reaction systems (either calculated from the specific surface area or derived from broadening the XRD reflections). The transmission electron micrographs indicated mostly globular shape of the nanosize particles. Quantitative analysis of the surface of the powders by X-ray photoelectron spectroscopy revealed the presence of oxygen and carbon. Evaluating the spectra of the powders prepared from NZP, and taking in the account its spherical shape, a ZrC core covered by a very thin (≈1.0 nm) ZrO2 layer may be accounted for the measured oxygen and a thicker carbonaceous layer.

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“…This finding supports the above observations related to lowered thermal stability. Carbon materials with lower degree of structural ordering have smaller thermal resistance to oxidation [24,25].…”

Section: Resultsmentioning

confidence: 99%

Corrosion resistance studies of carbon-encapsulated iron nanoparticles

et al. 2017

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The carbon coating in carbon-encapsulated magnetic nanoparticles is considered as a tight and impermeable barrier which should perfectly protect the magnetic core material from external chemical environment. To study the integrity of the coating, carbon-encapsulated iron nanoparticles were subjected to corrosion tests, in which various corrosion agents were used. Several mineral and organic acids, as well as active gaseous environments with various oxidation potential, were applied. Additionally, the corrosion resistance was studied under the so-called galvanic corrosion, using two metal ions (copper and silver) which have higher redox potential than the zero-valent iron. The release of iron from the core as well as the morphology, structural features, chemical composition, and magnetic properties of carbon-encapsulated iron nanoparticles was systematically monitored at each stage of the corrosion process. The largest release of Fe from the encapsulate core was observed when nitric acid was used as the corrosion agent.

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Continuous and catalyst free synthesis of graphene sheets in thermal plasma jet

Cited by 32 publications

References 60 publications

Carbon Fibers Obtained from Flax and Their Adsorption Performance in the Removal of Cu(II) and Co(II) from Aqueous Solutions

Carbon Fibers Obtained from Flax and Their Adsorption Performance in the Removal of Cu(II) and Co(II) from Aqueous Solutions

In-flight Synthesis of Nanosized ZrC Particles from Various Precursors in RF Thermal Plasma

Corrosion resistance studies of carbon-encapsulated iron nanoparticles

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