The Synthesis of Carbon Nanoparticles in a Compression Reactor in the Atmosphere of Buffer Gases
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We investigated the physicochemical aspects of the gas-phase nanopowder synthesis using a cyclic compression reactor. Compression of precursors (methane, ethylene, acetylene) under conditions close to the adiabatic ones in the atmosphere of buffer monatomic gases (argon, helium, neon) was used. The influence of pressure in the reactor and volumetric ratio of precursor/buffer gas mixture on the composition, morphology, and structure of carbon-containing particles representing the pyrolysis product was studied. Complete pyrolysis was observed for all studied precursors, but under different conditions. Thermal decomposition of methane, having the minimum enthalpy of formation, was observed in an atmosphere with argon content 97.5 % at a peak pressure more than 10 MPa. Helium showed limited possibilities for thermal relaxation under the conditions of fast reactions (< 50 ms). Only acetylene with the maximum enthalpy of formation was decomposed in the atmosphere of helium. The solid reaction products represented black colored powders with a bulk density of 20–30 mg/cm3 . The powders were examined by transmission electron microscopy and scanning electron microscopy, Raman scattering and X-ray diffraction analysis. The particles represent globular bulbous structures up to 100 nm in size, either hollow or filled inside. X-ray diffraction analysis showed the presence of a graphite-like structure with crystallite sizes less than 10 nm in all samples. Raman analysis showed mainly sp2 hybridization of carbon. The cyclic compression method demonstrates wide range of opportunities for the pyrolysis of hydrocarbons aiming at the production of a variety of carbon structures, which enables for the fine tuning in terms of the yield of products of the required morphology for practical use.
Keywords
cyclic chemical reactor, adiabatic compression, pyrolysis of hydrocarbons, carbon nanomaterials, buffer gas
Funding
The experimental work on the production and studying the properties of carbon nanomaterials, except for XRD, was carried out with the financial support of the Ministry of Science and Higher Education of the Russian Federation, project No. FSUS-2020-0039. The study of the properties of carbon nanomaterials by XRD was carried out with the financial support of the Ministry of Science and Higher Education of the Russian Federation, project N121031700321-3. The work was carried out on the equipment of the Applied Physics Center for Collective Use of the Physics Faculty of the Novosibirsk State University (NSU); measurements were performed on the equipment of the Center for Collective Use “VTAN” in the ATRC department of NSU.
УДК 66.092-977;54.057
The Synthesis of Carbon Nanoparticles in a Compression Reactor in the Atmosphere of Buffer Gases
The material was received by the Editorial Board: 29.04.2022
Abstract We investigated the physicochemical aspects of the gas-phase nanopowder synthesis using a cyclic compression reactor. Compression of precursors (methane, ethylene, acetylene) under conditions close to the adiabatic ones in the atmosphere of buffer monatomic gases (argon, helium, neon) was used. The influence of pressure in the reactor and volumetric ratio of precursor/buffer gas mixture on the composition, morphology, and structure of carbon-containing particles representing the pyrolysis product was studied. Complete pyrolysis was observed for all studied precursors, but under different conditions. Thermal decomposition of methane, having the minimum enthalpy of formation, was observed in an atmosphere with argon content 97.5 % at a peak pressure more than 10 MPa. Helium showed limited possibilities for thermal relaxation under the conditions of fast reactions (< 50 ms). Only acetylene with the maximum enthalpy of formation was decomposed in the atmosphere of helium. The solid reaction products represented black colored powders with a bulk density of 20–30 mg/cm3 . The powders were examined by transmission electron microscopy and scanning electron microscopy, Raman scattering and X-ray diffraction analysis. The particles represent globular bulbous structures up to 100 nm in size, either hollow or filled inside. X-ray diffraction analysis showed the presence of a graphite-like structure with crystallite sizes less than 10 nm in all samples. Raman analysis showed mainly sp2 hybridization of carbon. The cyclic compression method demonstrates wide range of opportunities for the pyrolysis of hydrocarbons aiming at the production of a variety of carbon structures, which enables for the fine tuning in terms of the yield of products of the required morphology for practical use.
Keywords
cyclic chemical reactor, adiabatic compression, pyrolysis of hydrocarbons, carbon nanomaterials, buffer gas
Funding
The experimental work on the production and studying the properties of carbon nanomaterials, except for XRD, was carried out with the financial support of the Ministry of Science and Higher Education of the Russian Federation, project No. FSUS-2020-0039. The study of the properties of carbon nanomaterials by XRD was carried out with the financial support of the Ministry of Science and Higher Education of the Russian Federation, project N121031700321-3. The work was carried out on the equipment of the Applied Physics Center for Collective Use of the Physics Faculty of the Novosibirsk State University (NSU); measurements were performed on the equipment of the Center for Collective Use “VTAN” in the ATRC department of NSU.
УДК 66.092-977;54.057
The Synthesis of Carbon Nanoparticles in a Compression Reactor in the Atmosphere of Buffer Gases References: Ezdin B. S., Vasiljev S. A., Yatsenko D. A., Fedorov V. E., Ivanova M. N., Kalyada V. V., Pakharukov Yu. V., Shabiev F. K., Zarvin A. E. The Synthesis of Carbon Nanoparticles in a Compression Reactor in the Atmosphere of Buffer Gases. Siberian Journal of Physics. 2022, vol. 17, no. 3. P. 29–46 (in Russ.). DOI: 10.25205/2541-9447-2022-17-3-29-46