Synthesis and Characteristics of Graphene-Graphene Oxide Material Obtained by an Underwater Impulse Direct Current Discharge

Synthesis and Characteristics of Graphene-Graphene Oxide Material Obtained by an Underwater Impulse Direct Current Discharge | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Synthesis and Characteristics of Graphene-Graphene Oxide Material Obtained by an Underwater Impulse Direct Current Discharge Nikolay Sirotkin, Viktor Korolev This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2607964/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This work proposed a novel approach, in which an impulse underwater discharge was used to produce graphene-graphene oxide material in distilled water. The characteristics of this discharge were presented, including electrical parameters, plasma composition, and electron concentration. Graphene-based material produced using this approach can be evenly dispersed in water without the use of a surfactant or stabilizer, and is suitable for storage at room temperature. Ultraviolet–visible spectroscopy was employed to analyze the optical properties of the graphene-based structures. Scanning electron microscopy was adopted to explore the morphology and size of the particles. The FTIR spectroscopy confirms the formation of graphene oxide. The Raman spectroscopy demonstrates the formation of a graphene-containing multilayer material. The results of this study confirmed that graphene-based material production by impulse underwater discharge is a low-cost, fast, and effective manufacturing method. plasma underwater discharge graphene graphene oxide Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 1. Introduction Graphene, a two-dimensional honeycomb sheet composed of sp 2 -hybridized carbon atoms, exhibits many extraordinary properties due to its two-dimensional (2D) crystal structure. Graphene has excellent qualities, including unique electronic properties due to its high electron mobility, mechanical resistivity, superthermal properties, large surface area, high light transmittance, etc. [ 1 – 2 ]. These properties pave the way for the application of graphene in capacitors, batteries, actuators, biosensors, etc. [ 3 – 5 ]. Graphene can be obtained by various processes, including chemical vapor deposition [ 6 ], micromechanical cracking of graphite [ 7 ] and exfoliation of graphite [ 8 ]. However, many of these methods are very laborious and expensive. Currently, graphene is mainly produced by chemically oxidizing graphite to graphene oxide (GO) and then producing graphene [ 9 ]. Graphene oxide, an oxidized derivative of graphene, is currently used in biotechnology and medicine for cancer therapy, drug delivery, and cell imaging [ 10 , 11 ]. In addition, GO possesses various physicochemical properties, including nanoscale size, high surface area, and charge [ 12 , 13 ]. Therefore, both graphene oxide and graphene have unique properties and are future materials with broad application prospects. It was found that low-layer graphene was successfully prepared by an arc discharge process in deionized water. Samples were collected from three different locations. These samples were characterized by Raman spectroscopy. It can be seen that, as a result of the experiments, multilayer and multilayer graphene were produced [ 14 ]. The arc discharge method has achieved the preparation of high-purity graphene. The current was kept at 100–150 A during the discharge process. The atmospheres for arc evaporation of graphite rods are H 2 , NH 3 and air [ 15 ]. For GO reduction several studies using plasma methods, including hydrogen plasma, atmospheric plasma have been explored [ 16 , 17 ]. However, gas-phase plasma processes for various gaseous substances usually require complex gas path connection systems, which increase operating costs. Furthermore, the gaseous precursors used (including hydrogen, ammonia, methane) are explosive or corrosive in nature, which poses safety concerns and limits their industrial scalability for practical applications. Experimental results show that liquid microwave discharge plasma can effectively reduce GO solution, further restore the π-conjugated structure of graphene at low temperature, and prepare plasma-treated reduced graphene oxide with low oxygen and high conductivity [ 18 ]. But in this work, graphene was reduced from chemically synthesized graphene oxide. Graphene was prepared in deionized water by the submerged arc discharge method. The authors obtained a stable graphene suspension. In this work, a pulsed arc microdischarge with a current of about 4 A was used to synthesize graphene [ 19 ]. The studies found that impulse underwater discharge initiated by a direct current source is a efficient method to obtain various nanoparticles [ 20 – 22 ]. It is a simple and fast method that does not require sophisticated equipment, harmful chemicals or the use of an inert atmosphere. In this study, we carried out and analyzed the results of a one-step synthesis of graphene-containing particles, using the low current underwater impulse discharge in liquid. 2. Experimental Part 2.1 Experimental setup Figure 1 presented the scheme of the setup for the synthesis of graphene-containing materials use the impulse underwater discharge. The impulse underwater discharge was excited between two graphite rods 5 mm in size. The graphite rods (CJSC "Grafitservis", Russia, and graphite content 99.99%, density 1.814 g cm − 3 ) were placed in heat-resistant glass tubes 7 mm in diameter. To excite the discharge, the DC power supply BP-0.25-2 (LLC "TD ARS THERM", Russia) with output voltage up to 5 kV and 0.5 kOhm ballast resistor was used. The value of voltage drop between anode - cathode were recorded using the multichannel digital oscilloscope Hantek-4104B (Hantek, China) and then processed on a computer. The voltage measurement circuit included voltage divider (DNV-80i (CJSC “Electroprom”, Russia) with a division ratio of 1: 1000 was used to measure the voltage drop. The waveform of the current was also measured using an oscilloscope. The average values of current, the voltage of the discharge and power dissipation were obtained by averaging samples of waveforms within 30 seconds of measurements by the equations presented in the work [ 23 ]. The average discharge current was 0.25 A. The experiments were carried out in the plasma cell with a fixed solution volume of 200 mL and with a flat optical quartz window. The real-time images of discharges were recorded by high-speed camera Baumer VСXU-04M with a frame rate 430 frames per second with AZURE-0918M3M lens. The discharge emission spectra (λ = 200 − 950 nm) were recorded by the AvaSpec ULS-3648 (Avantes, Netherlands) spectrometer with resolution 0.3 nm. The diffraction grating was a dispersing element. The electrodes were weighed before and after the ignition of the discharge to determine the mass production rate of graphene-containing particles. The analytical balance AND HR-150AZ, with a measurement error of 5% was used. The obtained suspension of graphene-containing particles was dried at room temperature for further physical studies. 2.2 Characterization The surface morphology of graphene-containing was obtained with the scanning electron microscopy (Quattro S, Thermo Fisher Scientific, Czech Republic). The phase composition of obtained structures was analyzed by X-ray diffraction (X-ray diffractometer D2 Advance, Brucker, CuK α source). The interpretation of diffractograms was performed with the use of the COD open crystallographic database. FTIR spectra of synthesized particleswere recorded using the VERTEX-80v spectrometer (Brucker Optics, Germany) with 0.2 cm − 1 resolution in the range of 4000 − 400 cm − 1 . Raman spectra of the samples were recorded with Confotec NR500 Raman microscope by using 532 nm excitation wavelengths. The spectra of aqueous suspension were analyzed by a spectrophotometer SF-56 (Spectr, Russia) in the range of wavelengths 210–850 nm. 3. Results And Discussions 3.1 The characteristics of a pulsed underwater discharge during the synthesis of graphene-containing particles The development of the discharge begins with the formation of a gas bubbles near the electrodes according to Fig. 2 . In the initial phase of electrolysis, chemical processes of release of oxygen and hydrogen take place on the electrodes. At the initial moment of time, the solution is still insufficiently heated. It can be assumed that this is not a bubble of water vapor but oxygen, or at least it consists mainly of oxygen. When the interelectrode space is filled with a gas bubble, a breakdown occurs and a discharge develops, which leads to a sharp increase in current. An increase in current causes overheating of the solution and an expansion in the bubble diameter due to the formation of water vapor. In contrast to the discharge initiated between two metallic electrodes, two discharge pulses follow one after the other (Fig. 3 ).This can be explained by the relative position of the electrodes. The initial breakdown occurs at the tips of the electrodes where the distance is minimal. The first discharge pulse initiates the development of the second pulse. Furthermore, the current decreases and the process repeat. The active burning time of the discharge is about 7 ms. A breakdown of liquid causes a sharp increase in the amplitude of the voltage and current. The amplitude value of current is 3 A. The amplitude value of the voltage is 1.8 kV. Thus the discharge can be called a pulsed, excited by source of direct current. The data obtained from the multichannel digital oscilloscope was processed on a computer according to the ratios presented in study [ 23 ]. The discharge power dissipated into the liquid is the sum of the power dissipated by the current in the solution and the power dissipated by the discharge. Therefore, each value of the magnitude of the discharge power shall be subtracted from the corresponding value of the magnitude of the power that would have been consumed if no discharge had developed in the battery. To simplify the calculation, we take the average amplitude value of the power dissipated during discharge minus the average amplitude value of the power dissipated in the battery when no discharge occurs. $${E}_{d}={(P}_{d}-{P}_{p})\times {(t}_{1}-{t}_{0})$$ 1 Where P d is the total value of the power dissipated by the flow of current in the solution and the power dissipated in the discharges, P p is the power dissipated in the cell without the formation of discharges, t 1 - t 0 is the duration of the discharge. The obtained discharge energy characteristics are shown in Table 1 . The power value of the discharge is obtained higher than in the case of underwater impulse discharge burning between two metal electrodes where the discharge power is 22 W. Whereas the energy of discharge is less than the energy of discharge initiated between two metal electrodes where value is about 65 J [ 23 ]. The estimates of the energy consumption for the formation of mixed oxides particle were made using the relationship: η = P d /v , where v is the rate of formation of graphene powder [ 24 ]. The values of the average rate were determined from the difference of the masses of the electrodes before and after the discharge burning. The average energy consumption is about 950 eV atom -1 (Table 1 ). The obtained results of energy consumption are comparable with the results on the synthesis of metal oxide particles using nanosecond plasma (75–600 eV atom -1 ) presented in [ 25 ]. It should be noted that the energy consumption for producing graphene in arc discharges in water [ 19 ] is larger. The emission spectrum of a discharge is presented in Fig. 4 . The atomic oxygen lines at 777 and 844 nm and hydrogen Balmer lines of H γ at 434 nm, H β at 486 nm and H α at 656 nm are registered. The bands of OH radicals in the range of 280–340 nm are represented. "Swan-band" emission from C 2 has been registered to range from 461 to 481 nm for the Δ v = 1 sequence, from 501 to 517 nm for the Δ v = 0 sequence [ 26 ]. In addition, the emission lines of atomic carbon at 472 nm and 494 nm and the bands of the CH radicals (A 2 Δ-X 2 П) in the region of 425–430 nm are present in the emission spectrum of the discharge [ 27 ]. The presence of lines and bands of carbon-containing particles in the emission spectrum may indicate the sputtering of the electrode material and the reactions occurring in the plasma with the participation of these particles. We used the software CyberWit Diatomic 1.4.1.1 [ 28 ] to determine the rotational temperature. The OH emission spectra in the wavelength range corresponding to the OH transition band (A 2 Σ→X 2 Π) were simulated The temperature was determined by fitting the synthetic spectrum to the experimental spectrum of the hydroxyl radical transition emission band in the 280–310 nm range using the CyberWit Diatomic program. The rotational temperature of OH radicals was used as fitting parameters to minimize the sum of the squared deviations of the calculated band profiles from the measured ones. The rotational temperature of OH in the plasma is about 4500 K. The value of the rotational temperature of hydroxyl radicals can be identified with the gas temperature in the plasma bulk. In this work, the Stark broadening of the 𝐻 𝛼 line is used, to determine electron densities 𝑛 e . An approximation formula for the electron density 𝑛 e (in cm − 3 ) dependent on the full width of half area (FWHA) of the Stark profile Δ𝜆 𝐹𝑊𝐻𝐴 S (in nm) is given by Gigosos et al. [ 29 ]. $${n}_{e}={10}^{17}\times {\left(\frac{\varDelta {\lambda }_{S}^{FWHA}}{1.098}\right)}^{1.47135}$$ 2 For the Lorentzian distribution, van der Waals broadening and Stark broadening are considered only. Using data on the molar fractions of components in the plasma, taking into account the energies of possible transitions and reduced masses, the final expression for the van der Waals FWHA of H α can be written as: $$\varDelta {\lambda }_{VdW}\approx 1.8\bullet p/{T}^{0.7}$$ 3 The obtained data are presented in Table 1 . Table 1 Parameters of the underwater impulse discharge with graphite electrodes ( i = 0.25 A). Frequency, s − 1 E d , J P d , W n e ×10 16 , cm − 3 T rot , K η , eV atom − 1 Graphite electrodes 24 ± 3 6.7 ± 0.9 150 ± 15 1.2 ± 0.5 4500 ± 300 950 ± 100 E d – discharge energy, P d – discharge power, n e – electron concentration, T rot – rotational temperature of OH radicals, η – energy consumption. The UV-Visible absorption spectra of synthesized suspension with graphene-containing particles (red curve) and graphite powder (black curve) dispersed in deionized water is shown in Fig. 5 . The particles were stably suspended in water instead of depositing as sediment. As seen from the Fig. 5 , the graphite powder has only a shoulder at about 275 nm, whereas graphene-containing particles has shoulder peak at 298 nm. The UV–Vis spectra obtained in the present study matches well with the previous studies [ 30 ]. An absorption peak shoulder at 298 nm agrees to the n–π* transition of the C = O group. The obtained observation confirms the formation of graphene oxide (GO) [ 31 ]. Powder XRD measurements were carried out to describe and observe the structure and formed phases of the fabricated materials. The average crystalline size and microstrain values of the materials were calculated via Scherrer’s equations, $$D= \frac{0.9\lambda }{\beta cos{\Theta }}$$ 4 $$\epsilon = \frac{\beta }{4tan{\Theta }}$$ 5 where, d and ε are the crystalline size and micro-strain of the materials respectively, λ is the wavelength of X-ray radiation, β is the full width half maximum value (FWHM) and θ is the diffraction angle [ 32 ]. The Bragg’s equation was applied to (002) reflection for evaluating the distance between graphene layers, denoted as d: $$d= \frac{\lambda }{2sin\theta }$$ 6 Figure 6 displays the typical XRD patterns of initial graphite and synthesized graphene-containing powder. The graphite shows a sharp and tight peak (2θ = 26.5°) which corresponds to the diffraction line C (002) with the intercellular spacing in the crystal is 3.2 Å. The data shows the typical crystal structure of graphite. The GO shows two diffraction peaks at 2θ = 10.4° and 42.2° that correspond to (001) and (100) diffraction planes with the spacing between plane is about 8.8 Å. [ 32 ]. Increasing the distance between layers in the graphene oxide is due to the presence of oxygen-functional groups and water molecules into the carbon layer structure. The peak is observed at 2θ = 23.9° which indicates that graphene oxide is not fully interconnected with oxygen atoms. Thus, graphene is also present in the sample in a fairly large amount. The resulting graphene has a structure between the crystalline and amorphous structures. This is evidenced by the appearance of the diffraction line C (002) which looks wider and the intensity is lower than the peak obtained in the graphite powder. The Scherrer equation with Warren constant of 1.84 [ 33 ] was applied to two dimensional (10) reflection for estimating the average size of stacking layers, denoted as L. If each parallel layer consists of n layers, L for a parallel layer group is defined as L = (n– 1)· d , or n = ( L + d )/ d [ 34 ]. The obtained graphene-containing particles consists of 7–8 layers in a stacking nanostructure with layer distance about of 0.75 nm. XRD analysis data are presented in Table 2 . Table 2 Structural parameters of obtained graphene-based material resulting from the XRD patterns. d , nm L , nm D , nm n \(\epsilon\) Graphene 0.65 10 25 8–10 0.00109 Graphene oxide 0.88 7 14 7–8 0.00115 D – crystalline size of GO and graphene, n – average number of layers in stacking layers, d – average distance between layers, L – average height of GO and graphene stacking layers, ɛ – microstrain value. SEM images of the obtained sample are shown in Fig. 7 . The average size of the scales can be estimated at several micrometers, although smaller scales may be observed. The number of layers corresponds to the results obtained from X-ray phase analysis. FTIR spectra of initial graphite and obtained graphene-containing powder are presented in Fig. 8 . The spectrum of the initial graphite shows only bands related to C = C and C–H bond vibrations. Figure 8 shows that synthesized powder has a peaks at 1081 cm − 1 which is attributed to the C-O bond of GO, confirming the presence of oxide functional groups after the oxidation process in discharge plasma. It can be noted the peaks appear in graphite oxide at 3422, 1737, 1639, 1380, and 1250 cm − 1 due to –OH stretching, C = O (carboxyl) stretching, C = O, –OH bending and C-OH stretching [ 35 ]. The absorbed water in GO is shown by a broad peak at 2885 cm − 1 to 3715 cm − 1 , contributed by the O-H stretch of H 2 O molecules [ 36 ]. This supports the fact that GO is a highly absorptive material. In graphene, the Stokes phonon energy shift induced by laser excitation produces two main peaks in the Raman spectrum: G, a primary in-plane vibrational mode, and 2D, a second-order overtone of a different in plane vibration, D [ 37 ] (Fig. 9 ). The D and 2D peak positions are dispersed depending on laser excitation energy [ 38 ]. As shown in Fig. 9 , the Raman spectrum of initial graphite exhibits strong lines at 1577 cm − 1 and 2685 cm − 1 , which are assigned to the G band and 2D band, respectively, while the D band is shown as a weak band at 1328 cm − 1 . The two most intense lines appearing at 1597 and 1330 cm − 1 for GO correspond to the G and D bands, respectively. As shown in the GO spectra, the D band shits to higher frequency and becomes prominent. Using the ratio of peak intensities I D / I G , one can use Raman spectra to characterize the level of disorder in graphene. As disorder in graphene increases, I D / I G displays 2 different behaviors. There is a regime of “low” defect density where I D / I G will increase as a higher defect density creates more elastic scattering. This occurs up to a regime of “high” defect density, at which point I D / I G will begin to decrease as an increasing defect density results in a more amorphous carbon structure, attenuating all Raman peaks [39]. The ratio of D to G band intensity ( I D / I G ) equals to 0.89, indicating the reduction in the average size of sp 2 domains due to extensive oxidation. The band at 2700 cm − 1 is known as the 2D band, which is an indicator of the number of graphene layers. Here, the band is observed to be broadened, attributed to the fact that the prepared graphene contains few layers with some defects. Conclusion In this work, we demonstrated a fast, effective, and environmentally friendly process for producing graphene-based material by using underwater impulse discharge. UV–vis, FTIR, Raman spectroscopy, and XRD analysis confirmed the presence of graphene and graphene oxide in the samples. Finally, a material containing up to 6-7 layers of graphene and graphene oxide was obtained. The discharge used in the synthesis of graphene-containing material is a pulsed discharge with pulse duration of about 7 milliseconds. The emission spectra of the plasma confirm the sputtering of graphite electrodes during discharge combustion and the occurrence of chemical processes involving carbon particles. The rate of formation of graphene-containing material is about 0.5 g/h, with an average energy consumption of about 950 eV per atom. Further research in this area will be aimed at selecting experimental conditions, including the discharge current, varying the material of graphite electrodes, additional exposure to ultrasonic waves, in order to obtain pure graphene or pure graphene oxide. Declarations Acknowledgment Authors would like to thank Dr. N. Fomina for conducting XRD analysis, Dr. M. Yurov for conducting SEM analysis, Dr. Yu. Fadeeva for conducting FTIR analysis, Dr. A. Dyshin and Mr. M. Kuzmikov for conducting Raman measurements at the center of joint use of scientific equipment (the Upper Volga Regional Center for Physical-Chemical Research, Russia). Funding Information This work is supported by the Russian Science Foundation under grant 23-23-00276. Authors’ Contributions NS wrote the main manuscript text and prepared Figures, performed an experiment to determine the properties of the discharge and synthesize the material. VK discussed the results and developed the general concept of the work. All authors reviewed the manuscript. All authors have read and approved the manuscript. References Georgakilas V, Tiwari JN, Kemp KC, Perman JA, Bourlinos AB, Kim KS, Zboril R (2016) Noncovalent functionalization of graphene and graphene oxide for energy materials, biosensing, catalytic, and biomedical applications. 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Biochem 41: 2322-2330. https://doi.org/10.1021/bi011954k Saito R, Hofmann M, Dresselhaus G, Jorio A, Dresselhaus MS (2011) Raman spectroscopy of graphene and carbon nanotubes, Adv Phys 30: 413-550. https://doi.org/10.1080/00018732.2011.582251 Ferrari AC (2007) Raman spectroscopy of graphene and graphite: Disorder, electron–phonon coupling, doping and nonadiabatic effects. Solid State Commun 143: 47-57. https://doi.org/10.1016/j.ssc.2007.03.052 Childres I, Jauregui LA, Park W, Cao H, Chen YP (2013) Raman spectroscopy of graphene and related materials. New developments in photon and materials research 1:1-20. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-2607964","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":177687439,"identity":"b7ffb0c2-54bd-4d23-b53d-22390937f108","order_by":0,"name":"Nikolay Sirotkin","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2UlEQVRIiWNgGAWjYDACdjDJLMcPoniI0sIMIY0lG0jVkrjhALFa+JuZj0n+qLE2Nr6R/OzBm4rDDOYzEvBrkTjMlmzMcyxdzuxGmrnhnDNpDDI3CGhhOMxj+JiB7bCx2Y0EM2neNhsGCQkCWuQP8384+OPf4cTNM9K/SfP+kyCsxeAwD+MD3rbDiRskcoC2NBBhi+FhNmNj3r50Y4kzb8ok5xxL45HgeYBfi9zx5meSP75Zy/G3p2+TeFNzWE6CnYAtCCAAUUlcbEIA/wESFI+CUTAKRsGIAgD7gz2t1ZyAhwAAAABJRU5ErkJggg==","orcid":"","institution":"Institute of Solution Chemistry RAS","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Nikolay","middleName":"","lastName":"Sirotkin","suffix":""},{"id":177687440,"identity":"1d8be4e9-e9c6-437e-940a-efe4b768d5b7","order_by":1,"name":"Viktor Korolev","email":"","orcid":"","institution":"Institute of Solution Chemistry RAS","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Viktor","middleName":"","lastName":"Korolev","suffix":""}],"badges":[],"createdAt":"2023-02-20 12:44:23","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2607964/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2607964/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":33294031,"identity":"b2ecea42-e47b-4838-bfed-013aec97a2ea","added_by":"auto","created_at":"2023-02-22 15:29:28","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":117030,"visible":true,"origin":"","legend":"\u003cp\u003eThe sketch of the discharge set-up.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-2607964/v1/7d56b62c4369633613f9d2c1.jpg"},{"id":33294030,"identity":"85162a70-0bb3-4ed6-9e90-94c4e8dd8a83","added_by":"auto","created_at":"2023-02-22 15:29:28","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":84676,"visible":true,"origin":"","legend":"\u003cp\u003eThe photos of underwater impulse discharge with graphite electrodes: a - before switching on the discharge, b - electrolysis, c - initial moment of breakdown, d - discharge impulse.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-2607964/v1/8b36a47f58fcbbd60b659846.jpg"},{"id":33294029,"identity":"c30f6930-1181-4b78-b5ea-26734f6d191a","added_by":"auto","created_at":"2023-02-22 15:29:28","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":28973,"visible":true,"origin":"","legend":"\u003cp\u003eThe waveforms of current and voltage of an underwater impulse discharge.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-2607964/v1/e078aa228822453222c8c6f4.png"},{"id":33294862,"identity":"43cc0f98-3c53-466a-b099-69eefab7dce5","added_by":"auto","created_at":"2023-02-22 15:37:28","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":65807,"visible":true,"origin":"","legend":"\u003cp\u003eThe emission spectrum of an underwater impulse discharge with graphite electrodes (\u003cem\u003ei\u003c/em\u003e= 0.25 A).\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-2607964/v1/e2932e620de9974a69c53681.jpg"},{"id":33294863,"identity":"3d2ffcc5-65b7-4efc-940d-a2e68b4393ff","added_by":"auto","created_at":"2023-02-22 15:37:28","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":41434,"visible":true,"origin":"","legend":"\u003cp\u003eUV–Vis absorption spectra of initial graphite and obtained suspension.\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-2607964/v1/f152255f65fcff22f92a8349.jpg"},{"id":33294861,"identity":"7f6bd763-b152-44b9-8845-092cc33ed5f8","added_by":"auto","created_at":"2023-02-22 15:37:28","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":59687,"visible":true,"origin":"","legend":"\u003cp\u003eXRD patterns of the graphite powder and synthesized graphene-containing powder.\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-2607964/v1/f969cd6ca67592d12ffcb071.jpg"},{"id":33294037,"identity":"fea5cf82-d171-4464-9660-af14736f76b8","added_by":"auto","created_at":"2023-02-22 15:29:29","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":263395,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images synthesized graphene-containing powder.\u003c/p\u003e","description":"","filename":"7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-2607964/v1/cbd942e514826ece47b2fb87.jpg"},{"id":33294015,"identity":"b0037ec2-a6dc-484e-aa66-2cfe5f51bf74","added_by":"auto","created_at":"2023-02-22 15:29:28","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":85834,"visible":true,"origin":"","legend":"\u003cp\u003eFTIR spectra of the initial graphite powder and synthesized graphene-containing powder.\u003c/p\u003e","description":"","filename":"8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-2607964/v1/aebdae60c9bcfc19c6fccf97.jpg"},{"id":33294033,"identity":"3b5fc702-d95e-4383-8d55-88a6dbf89e9e","added_by":"auto","created_at":"2023-02-22 15:29:28","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":68637,"visible":true,"origin":"","legend":"\u003cp\u003eRaman spectra of initial graphite powder and synthesized graphene-containing powder.\u003c/p\u003e","description":"","filename":"9.jpg","url":"https://assets-eu.researchsquare.com/files/rs-2607964/v1/4968696522551da030849159.jpg"},{"id":33461409,"identity":"a96750e3-a3ee-4b16-a492-c8675c212919","added_by":"auto","created_at":"2023-02-26 12:29:27","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":783511,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2607964/v1/58fbb1a8-c0e3-477f-8c07-3dd458ebc83e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Synthesis and Characteristics of Graphene-Graphene Oxide Material Obtained by an Underwater Impulse Direct Current Discharge","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eGraphene, a two-dimensional honeycomb sheet composed of sp\u003csup\u003e2\u003c/sup\u003e-hybridized carbon atoms, exhibits many extraordinary properties due to its two-dimensional (2D) crystal structure. Graphene has excellent qualities, including unique electronic properties due to its high electron mobility, mechanical resistivity, superthermal properties, large surface area, high light transmittance, etc. [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. These properties pave the way for the application of graphene in capacitors, batteries, actuators, biosensors, etc. [\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Graphene can be obtained by various processes, including chemical vapor deposition [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], micromechanical cracking of graphite [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] and exfoliation of graphite [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. However, many of these methods are very laborious and expensive. Currently, graphene is mainly produced by chemically oxidizing graphite to graphene oxide (GO) and then producing graphene [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Graphene oxide, an oxidized derivative of graphene, is currently used in biotechnology and medicine for cancer therapy, drug delivery, and cell imaging [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In addition, GO possesses various physicochemical properties, including nanoscale size, high surface area, and charge [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Therefore, both graphene oxide and graphene have unique properties and are future materials with broad application prospects.\u003c/p\u003e \u003cp\u003eIt was found that low-layer graphene was successfully prepared by an arc discharge process in deionized water. Samples were collected from three different locations. These samples were characterized by Raman spectroscopy. It can be seen that, as a result of the experiments, multilayer and multilayer graphene were produced [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. The arc discharge method has achieved the preparation of high-purity graphene. The current was kept at 100\u0026ndash;150 A during the discharge process. The atmospheres for arc evaporation of graphite rods are H\u003csub\u003e2\u003c/sub\u003e, NH\u003csub\u003e3\u003c/sub\u003e and air [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. For GO reduction several studies using plasma methods, including hydrogen plasma, atmospheric plasma have been explored [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. However, gas-phase plasma processes for various gaseous substances usually require complex gas path connection systems, which increase operating costs. Furthermore, the gaseous precursors used (including hydrogen, ammonia, methane) are explosive or corrosive in nature, which poses safety concerns and limits their industrial scalability for practical applications. Experimental results show that liquid microwave discharge plasma can effectively reduce GO solution, further restore the π-conjugated structure of graphene at low temperature, and prepare plasma-treated reduced graphene oxide with low oxygen and high conductivity [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. But in this work, graphene was reduced from chemically synthesized graphene oxide. Graphene was prepared in deionized water by the submerged arc discharge method. The authors obtained a stable graphene suspension. In this work, a pulsed arc microdischarge with a current of about 4 A was used to synthesize graphene [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe studies found that impulse underwater discharge initiated by a direct current source is a efficient method to obtain various nanoparticles [\u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. It is a simple and fast method that does not require sophisticated equipment, harmful chemicals or the use of an inert atmosphere.\u003c/p\u003e \u003cp\u003eIn this study, we carried out and analyzed the results of a one-step synthesis of graphene-containing particles, using the low current underwater impulse discharge in liquid.\u003c/p\u003e"},{"header":"2. Experimental Part","content":"\u003cdiv class=\"Section2\" id=\"Sec3\"\u003e\n \u003ch2\u003e2.1 Experimental setup\u003c/h2\u003e\n \u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e presented the scheme of the setup for the synthesis of graphene-containing materials use the impulse underwater discharge. The impulse underwater discharge was excited between two graphite rods 5 mm in size. The graphite rods (CJSC \u0026quot;Grafitservis\u0026quot;, Russia, and graphite content 99.99%, density 1.814 g cm\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e) were placed in heat-resistant glass tubes 7 mm in diameter. To excite the discharge, the DC power supply BP-0.25-2 (LLC \u0026quot;TD ARS THERM\u0026quot;, Russia) with output voltage up to 5 kV and 0.5 kOhm ballast resistor was used. The value of voltage drop between anode - cathode were recorded using the multichannel digital oscilloscope Hantek-4104B (Hantek, China) and then processed on a computer. The voltage measurement circuit included voltage divider (DNV-80i (CJSC \u0026ldquo;Electroprom\u0026rdquo;, Russia) with a division ratio of 1: 1000 was used to measure the voltage drop. The waveform of the current was also measured using an oscilloscope. The average values of current, the voltage of the discharge and power dissipation were obtained by averaging samples of waveforms within 30 seconds of measurements by the equations presented in the work [\u003cspan class=\"CitationRef\"\u003e23\u003c/span\u003e]. The average discharge current was 0.25 A.\u003c/p\u003e\n \u003cp\u003eThe experiments were carried out in the plasma cell with a fixed solution volume of 200 mL and with a flat optical quartz window. The real-time images of discharges were recorded by high-speed camera Baumer VСXU-04M with a frame rate 430 frames per second with AZURE-0918M3M lens. The discharge emission spectra (\u0026lambda;\u0026thinsp;=\u0026thinsp;200\u0026thinsp;\u0026minus;\u0026thinsp;950 nm) were recorded by the AvaSpec ULS-3648 (Avantes, Netherlands) spectrometer with resolution 0.3 nm. The diffraction grating was a dispersing element. The electrodes were weighed before and after the ignition of the discharge to determine the mass production rate of graphene-containing particles. The analytical balance AND HR-150AZ, with a measurement error of 5% was used. The obtained suspension of graphene-containing particles was dried at room temperature for further physical studies.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec4\"\u003e\n \u003ch2\u003e2.2 Characterization\u003c/h2\u003e\n \u003cp\u003eThe surface morphology of graphene-containing was obtained with the scanning electron microscopy (Quattro S, Thermo Fisher Scientific, Czech Republic).\u003c/p\u003e\n \u003cp\u003eThe phase composition of obtained structures was analyzed by X-ray diffraction (X-ray diffractometer D2 Advance, Brucker, CuK\u003csub\u003e\u0026alpha;\u003c/sub\u003e source). The interpretation of diffractograms was performed with the use of the COD open crystallographic database.\u003c/p\u003e\n \u003cp\u003eFTIR spectra of synthesized particleswere recorded using the VERTEX-80v spectrometer (Brucker Optics, Germany) with 0.2 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e resolution in the range of 4000\u0026thinsp;\u0026minus;\u0026thinsp;400 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.\u003c/p\u003e\n \u003cp\u003eRaman spectra of the samples were recorded with Confotec NR500 Raman microscope by using 532 nm excitation wavelengths.\u003c/p\u003e\n \u003cp\u003eThe spectra of aqueous suspension were analyzed by a spectrophotometer SF-56 (Spectr, Russia) in the range of wavelengths 210\u0026ndash;850 nm.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3. Results And Discussions","content":"\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n\u003ch2\u003e3.1 The characteristics of a pulsed underwater discharge during the synthesis of graphene-containing particles\u003c/h2\u003e\n\u003cp\u003eThe development of the discharge begins with the formation of a gas bubbles near the electrodes according to Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. In the initial phase of electrolysis, chemical processes of release of oxygen and hydrogen take place on the electrodes. At the initial moment of time, the solution is still insufficiently heated. It can be assumed that this is not a bubble of water vapor but oxygen, or at least it consists mainly of oxygen. When the interelectrode space is filled with a gas bubble, a breakdown occurs and a discharge develops, which leads to a sharp increase in current. An increase in current causes overheating of the solution and an expansion in the bubble diameter due to the formation of water vapor. In contrast to the discharge initiated between two metallic electrodes, two discharge pulses follow one after the other (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).This can be explained by the relative position of the electrodes. The initial breakdown occurs at the tips of the electrodes where the distance is minimal. The first discharge pulse initiates the development of the second pulse. Furthermore, the current decreases and the process repeat. The active burning time of the discharge is about 7 ms.\u003c/p\u003e\n\u003cp\u003eA breakdown of liquid causes a sharp increase in the amplitude of the voltage and current. The amplitude value of current is 3 A. The amplitude value of the voltage is 1.8 kV. Thus the discharge can be called a pulsed, excited by source of direct current. The data obtained from the multichannel digital oscilloscope was processed on a computer according to the ratios presented in study [\u003cspan class=\"CitationRef\"\u003e23\u003c/span\u003e]. The discharge power dissipated into the liquid is the sum of the power dissipated by the current in the solution and the power dissipated by the discharge. Therefore, each value of the magnitude of the discharge power shall be subtracted from the corresponding value of the magnitude of the power that would have been consumed if no discharge had developed in the battery. To simplify the calculation, we take the average amplitude value of the power dissipated during discharge minus the average amplitude value of the power dissipated in the battery when no discharge occurs.\u003c/p\u003e\n\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\n\u003cdiv id=\"FileID_Equ1\" class=\"mathdisplay\"\u003e$${E}_{d}={(P}_{d}-{P}_{p})\\times {(t}_{1}-{t}_{0})$$\u003c/div\u003e\n\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\n\u003c/div\u003e\n\u003cp\u003eWhere \u003cem\u003eP\u003c/em\u003e\u003csub\u003ed\u003c/sub\u003e is the total value of the power dissipated by the flow of current in the solution and the power dissipated in the discharges, \u003cem\u003eP\u003c/em\u003e\u003csub\u003ep\u003c/sub\u003e is the power dissipated in the cell without the formation of discharges, \u003cem\u003et\u003c/em\u003e\u003csub\u003e1\u003c/sub\u003e- \u003cem\u003et\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e is the duration of the discharge.\u003c/p\u003e\n\u003cp\u003eThe obtained discharge energy characteristics are shown in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. The power value of the discharge is obtained higher than in the case of underwater impulse discharge burning between two metal electrodes where the discharge power is 22 W. Whereas the energy of discharge is less than the energy of discharge initiated between two metal electrodes where value is about 65 J [\u003cspan class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e\n\u003cp\u003eThe estimates of the energy consumption for the formation of mixed oxides particle were made using the relationship: \u003cem\u003e\u0026eta;\u0026thinsp;=\u0026thinsp;P\u003c/em\u003e\u003csub\u003ed\u003c/sub\u003e\u003cem\u003e/v\u003c/em\u003e, where \u003cem\u003ev\u003c/em\u003e is the rate of formation of graphene powder [\u003cspan class=\"CitationRef\"\u003e24\u003c/span\u003e]. The values of the average rate were determined from the difference of the masses of the electrodes before and after the discharge burning. The average energy consumption is about 950 eV atom\u003csup\u003e-1\u003c/sup\u003e (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). The obtained results of energy consumption are comparable with the results on the synthesis of metal oxide particles using nanosecond plasma (75\u0026ndash;600 eV atom\u003csup\u003e-1\u003c/sup\u003e) presented in [\u003cspan class=\"CitationRef\"\u003e25\u003c/span\u003e]. It should be noted that the energy consumption for producing graphene in arc discharges in water [\u003cspan class=\"CitationRef\"\u003e19\u003c/span\u003e] is larger.\u003c/p\u003e\n\u003cp\u003eThe emission spectrum of a discharge is presented in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e. The atomic oxygen lines at 777 and 844 nm and hydrogen Balmer lines of H\u003csub\u003e\u0026gamma;\u003c/sub\u003e at 434 nm, H\u003csub\u003e\u0026beta;\u003c/sub\u003e at 486 nm and H\u003csub\u003e\u0026alpha;\u003c/sub\u003e at 656 nm are registered. The bands of OH radicals in the range of 280\u0026ndash;340 nm are represented. \"Swan-band\" emission from C\u003csub\u003e2\u003c/sub\u003e has been registered to range from 461 to 481 nm for the \u0026Delta;\u003cem\u003ev\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1 sequence, from 501 to 517 nm for the \u0026Delta;\u003cem\u003ev\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0 sequence [\u003cspan class=\"CitationRef\"\u003e26\u003c/span\u003e]. In addition, the emission lines of atomic carbon at 472 nm and 494 nm and the bands of the CH radicals (A\u003csup\u003e2\u003c/sup\u003e\u0026Delta;-X\u003csup\u003e2\u003c/sup\u003eП) in the region of 425\u0026ndash;430 nm are present in the emission spectrum of the discharge [\u003cspan class=\"CitationRef\"\u003e27\u003c/span\u003e]. The presence of lines and bands of carbon-containing particles in the emission spectrum may indicate the sputtering of the electrode material and the reactions occurring in the plasma with the participation of these particles. We used the software CyberWit Diatomic 1.4.1.1 [\u003cspan class=\"CitationRef\"\u003e28\u003c/span\u003e] to determine the rotational temperature. The OH emission spectra in the wavelength range corresponding to the OH transition band (A\u003csup\u003e2\u003c/sup\u003e\u0026Sigma;\u0026rarr;X\u003csup\u003e2\u003c/sup\u003e\u0026Pi;) were simulated The temperature was determined by fitting the synthetic spectrum to the experimental spectrum of the hydroxyl radical transition emission band in the 280\u0026ndash;310 nm range using the CyberWit Diatomic program. The rotational temperature of OH radicals was used as fitting parameters to minimize the sum of the squared deviations of the calculated band profiles from the measured ones. The rotational temperature of OH in the plasma is about 4500 K. The value of the rotational temperature of hydroxyl radicals can be identified with the gas temperature in the plasma bulk. In this work, the Stark broadening of the 𝐻\u003csub\u003e𝛼\u003c/sub\u003e line is used, to determine electron densities 𝑛\u003csub\u003ee\u003c/sub\u003e. An approximation formula for the electron density 𝑛\u003csub\u003ee\u003c/sub\u003e (in cm\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e) dependent on the full width of half area (FWHA) of the Stark profile \u0026Delta;𝜆\u003csup\u003e𝐹𝑊𝐻𝐴\u003c/sup\u003e\u003csub\u003eS\u003c/sub\u003e (in nm) is given by Gigosos et al. [\u003cspan class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e\n\u003cdiv id=\"Equ2\" class=\"Equation\"\u003e\n\u003cdiv id=\"FileID_Equ2\" class=\"mathdisplay\"\u003e$${n}_{e}={10}^{17}\\times {\\left(\\frac{\\varDelta {\\lambda }_{S}^{FWHA}}{1.098}\\right)}^{1.47135}$$\u003c/div\u003e\n\u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\n\u003c/div\u003e\n\u003cp\u003eFor the Lorentzian distribution, van der Waals broadening and Stark broadening are considered only. Using data on the molar fractions of components in the plasma, taking into account the energies of possible transitions and reduced masses, the final expression for the van der Waals FWHA of H\u003csub\u003e\u0026alpha;\u003c/sub\u003e can be written as:\u003c/p\u003e\n\u003cdiv id=\"Equ3\" class=\"Equation\"\u003e\n\u003cdiv id=\"FileID_Equ3\" class=\"mathdisplay\"\u003e$$\\varDelta {\\lambda }_{VdW}\\approx 1.8\\bullet p/{T}^{0.7}$$\u003c/div\u003e\n\u003cdiv class=\"EquationNumber\"\u003e3\u003c/div\u003e\n\u003c/div\u003e\n\u003cp\u003eThe obtained data are presented in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eParameters of the underwater impulse discharge with graphite electrodes (\u003cem\u003ei\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.25 A).\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eFrequency, s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eE\u003c/em\u003e\u003csub\u003ed\u003c/sub\u003e, J\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003csub\u003ed\u003c/sub\u003e, W\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003en\u003c/em\u003e\u003csub\u003ee\u003c/sub\u003e\u0026times;10\u003csup\u003e16\u003c/sup\u003e, cm\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u003csub\u003erot\u003c/sub\u003e, K\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003e\u0026eta;\u003c/em\u003e, eV atom\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eGraphite electrodes\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e24\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e6.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e150\u0026thinsp;\u0026plusmn;\u0026thinsp;15\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4500\u0026thinsp;\u0026plusmn;\u0026thinsp;300\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e950\u0026thinsp;\u0026plusmn;\u0026thinsp;100\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cem\u003eE\u003c/em\u003e \u003csub\u003ed\u003c/sub\u003e \u0026ndash; discharge energy, \u003cem\u003eP\u003c/em\u003e\u003csub\u003ed\u003c/sub\u003e \u0026ndash; discharge power, \u003cem\u003en\u003c/em\u003e\u003csub\u003ee\u003c/sub\u003e \u0026ndash; electron concentration, \u003cem\u003eT\u003c/em\u003e\u003csub\u003erot\u003c/sub\u003e \u0026ndash; rotational temperature of OH radicals, \u003cem\u003e\u0026eta; \u0026ndash;\u003c/em\u003e energy consumption.\u003c/p\u003e\n\u003cp\u003eThe UV-Visible absorption spectra of synthesized suspension with graphene-containing particles (red curve) and graphite powder (black curve) dispersed in deionized water is shown in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e. The particles were stably suspended in water instead of depositing as sediment. As seen from the Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e, the graphite powder has only a shoulder at about 275 nm, whereas graphene-containing particles has shoulder peak at 298 nm. The UV\u0026ndash;Vis spectra obtained in the present study matches well with the previous studies [\u003cspan class=\"CitationRef\"\u003e30\u003c/span\u003e]. An absorption peak shoulder at 298 nm agrees to the n\u0026ndash;\u0026pi;* transition of the C\u0026thinsp;=\u0026thinsp;O group. The obtained observation confirms the formation of graphene oxide (GO) [\u003cspan class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e\n\u003cp\u003ePowder XRD measurements were carried out to describe and observe the structure and formed phases of the fabricated materials. The average crystalline size and microstrain values of the materials were calculated via Scherrer\u0026rsquo;s equations,\u003c/p\u003e\n\u003cdiv id=\"Equ4\" class=\"Equation\"\u003e\n\u003cdiv id=\"FileID_Equ4\" class=\"mathdisplay\"\u003e$$D= \\frac{0.9\\lambda }{\\beta cos{\\Theta }}$$\u003c/div\u003e\n\u003cdiv class=\"EquationNumber\"\u003e4\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Equ5\" class=\"Equation\"\u003e\n\u003cdiv id=\"FileID_Equ5\" class=\"mathdisplay\"\u003e$$\\epsilon = \\frac{\\beta }{4tan{\\Theta }}$$\u003c/div\u003e\n\u003cdiv class=\"EquationNumber\"\u003e5\u003c/div\u003e\n\u003c/div\u003e\n\u003cp\u003ewhere, d and \u0026epsilon; are the crystalline size and micro-strain of the materials respectively, \u0026lambda; is the wavelength of X-ray radiation, \u0026beta; is the full width half maximum value (FWHM) and \u0026theta; is the diffraction angle [\u003cspan class=\"CitationRef\"\u003e32\u003c/span\u003e]. The Bragg\u0026rsquo;s equation was applied to (002) reflection for evaluating the distance between graphene layers, denoted as d:\u003c/p\u003e\n\u003cdiv id=\"Equ6\" class=\"Equation\"\u003e\n\u003cdiv id=\"FileID_Equ6\" class=\"mathdisplay\"\u003e$$d= \\frac{\\lambda }{2sin\\theta }$$\u003c/div\u003e\n\u003cdiv class=\"EquationNumber\"\u003e6\u003c/div\u003e\n\u003c/div\u003e\n\u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e displays the typical XRD patterns of initial graphite and synthesized graphene-containing powder. The graphite shows a sharp and tight peak (2\u0026theta;\u0026thinsp;=\u0026thinsp;26.5\u0026deg;) which corresponds to the diffraction line C (002) with the intercellular spacing in the crystal is 3.2 \u0026Aring;. The data shows the typical crystal structure of graphite. The GO shows two diffraction peaks at 2\u0026theta;\u0026thinsp;=\u0026thinsp;10.4\u0026deg; and 42.2\u0026deg; that correspond to (001) and (100) diffraction planes with the spacing between plane is about 8.8 \u0026Aring;. [\u003cspan class=\"CitationRef\"\u003e32\u003c/span\u003e]. Increasing the distance between layers in the graphene oxide is due to the presence of oxygen-functional groups and water molecules into the carbon layer structure. The peak is observed at 2\u0026theta;\u0026thinsp;=\u0026thinsp;23.9\u0026deg; which indicates that graphene oxide is not fully interconnected with oxygen atoms. Thus, graphene is also present in the sample in a fairly large amount. The resulting graphene has a structure between the crystalline and amorphous structures. This is evidenced by the appearance of the diffraction line C (002) which looks wider and the intensity is lower than the peak obtained in the graphite powder. The Scherrer equation with Warren constant of 1.84 [\u003cspan class=\"CitationRef\"\u003e33\u003c/span\u003e] was applied to two dimensional (10) reflection for estimating the average size of stacking layers, denoted as L. If each parallel layer consists of \u003cem\u003en\u003c/em\u003e layers, L for a parallel layer group is defined as \u003cem\u003eL\u003c/em\u003e = (n\u0026ndash; 1)\u0026middot;\u003cem\u003ed\u003c/em\u003e, or \u003cem\u003en\u003c/em\u003e = (\u003cem\u003eL\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003ed\u003c/em\u003e)/\u003cem\u003ed\u003c/em\u003e [\u003cspan class=\"CitationRef\"\u003e34\u003c/span\u003e]. The obtained graphene-containing particles consists of 7\u0026ndash;8 layers in a stacking nanostructure with layer distance about of 0.75 nm. XRD analysis data are presented in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eStructural parameters of obtained graphene-based material resulting from the XRD patterns.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ed\u003c/em\u003e, nm\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eL\u003c/em\u003e, nm\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eD\u003c/em\u003e, nm\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003en\u003c/em\u003e\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\epsilon\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eGraphene\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.65\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e10\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e25\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e8\u0026ndash;10\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.00109\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eGraphene oxide\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.88\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e7\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e14\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e7\u0026ndash;8\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.00115\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cem\u003eD\u003c/em\u003e \u0026ndash; crystalline size of GO and graphene, \u003cem\u003en\u003c/em\u003e \u0026ndash; average number of layers in stacking layers, \u003cem\u003ed \u0026ndash;\u003c/em\u003e average distance between layers, \u003cem\u003eL\u003c/em\u003e \u0026ndash; average height of GO and graphene stacking layers, \u003cem\u003eɛ\u003c/em\u003e \u0026ndash; microstrain value.\u003c/p\u003e\n\u003cp\u003eSEM images of the obtained sample are shown in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e. The average size of the scales can be estimated at several micrometers, although smaller scales may be observed. The number of layers corresponds to the results obtained from X-ray phase analysis.\u003c/p\u003e\n\u003cp\u003eFTIR spectra of initial graphite and obtained graphene-containing powder are presented in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e. The spectrum of the initial graphite shows only bands related to C\u0026thinsp;=\u0026thinsp;C and C\u0026ndash;H bond vibrations. Figure\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e shows that synthesized powder has a peaks at 1081 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e which is attributed to the C-O bond of GO, confirming the presence of oxide functional groups after the oxidation process in discharge plasma. It can be noted the peaks appear in graphite oxide at 3422, 1737, 1639, 1380, and 1250 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e due to \u0026ndash;OH stretching, C\u0026thinsp;=\u0026thinsp;O (carboxyl) stretching, C\u0026thinsp;=\u0026thinsp;O, \u0026ndash;OH bending and C-OH stretching [\u003cspan class=\"CitationRef\"\u003e35\u003c/span\u003e]. The absorbed water in GO is shown by a broad peak at 2885 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e to 3715 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, contributed by the O-H stretch of H\u003csub\u003e2\u003c/sub\u003eO molecules [\u003cspan class=\"CitationRef\"\u003e36\u003c/span\u003e]. This supports the fact that GO is a highly absorptive material.\u003c/p\u003e\n\u003cp\u003eIn graphene, the Stokes phonon energy shift induced by laser excitation produces two main peaks in the Raman spectrum: G, a primary in-plane vibrational mode, and 2D, a second-order overtone of a different in plane vibration, D [\u003cspan class=\"CitationRef\"\u003e37\u003c/span\u003e] (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e). The D and 2D peak positions are dispersed depending on laser excitation energy [\u003cspan class=\"CitationRef\"\u003e38\u003c/span\u003e]. As shown in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e, the Raman spectrum of initial graphite exhibits strong lines at 1577 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 2685 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, which are assigned to the G band and 2D band, respectively, while the D band is shown as a weak band at 1328 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The two most intense lines appearing at 1597 and 1330 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for GO correspond to the G and D bands, respectively.\u003c/p\u003e\n\u003cp\u003eAs shown in the GO spectra, the D band shits to higher frequency and becomes prominent. Using the ratio of peak intensities \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e/\u003cem\u003eI\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e, one can use Raman spectra to characterize the level of disorder in graphene. As disorder in graphene increases, \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e/\u003cem\u003eI\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e displays 2 different behaviors. There is a regime of \u0026ldquo;low\u0026rdquo; defect density where \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e/\u003cem\u003eI\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e will increase as a higher defect density creates more elastic scattering. This occurs up to a regime of \u0026ldquo;high\u0026rdquo; defect density, at which point \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e/\u003cem\u003eI\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e will begin to decrease as an increasing defect density results in a more amorphous carbon structure, attenuating all Raman peaks [39]. The ratio of D to G band intensity (\u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e/\u003cem\u003eI\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e) equals to 0.89, indicating the reduction in the average size of sp\u003csup\u003e2\u003c/sup\u003e domains due to extensive oxidation. The band at 2700 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e is known as the 2D band, which is an indicator of the number of graphene layers. Here, the band is observed to be broadened, attributed to the fact that the prepared graphene contains few layers with some defects.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn this work, we demonstrated a fast, effective, and environmentally friendly process for producing graphene-based material by using underwater impulse discharge. UV\u0026ndash;vis, FTIR, Raman spectroscopy, and XRD analysis confirmed the presence of graphene and graphene oxide in the samples. Finally, a material containing up to 6-7 layers of graphene and graphene oxide was obtained. The discharge used in the synthesis of graphene-containing material is a pulsed discharge with pulse duration of about 7 milliseconds. The emission spectra of the plasma confirm the sputtering of graphite electrodes during discharge combustion and the occurrence of chemical processes involving carbon particles. The rate of formation of graphene-containing material is about 0.5 g/h, with an average energy consumption of about 950 eV per atom. Further research in this area will be aimed at selecting experimental conditions, including the discharge current, varying the material of graphite electrodes, additional exposure to ultrasonic waves, in order to obtain pure graphene or pure graphene oxide.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAuthors would like to thank Dr. N. Fomina for conducting XRD analysis, Dr. M. Yurov for conducting SEM analysis, Dr. Yu. Fadeeva for conducting FTIR analysis, Dr. A. Dyshin and Mr. M. Kuzmikov for conducting Raman measurements at the center of joint use of scientific equipment (the Upper Volga Regional Center for Physical-Chemical Research, Russia).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding Information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work is supported by the Russian Science Foundation under grant 23-23-00276.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNS wrote the main manuscript text and prepared Figures, performed an experiment to determine the properties of the discharge and synthesize the material.\u003c/p\u003e\n\u003cp\u003eVK discussed the results and developed the general concept of the work.\u003c/p\u003e\n\u003cp\u003eAll authors reviewed the manuscript. All authors have read and approved the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eGeorgakilas V, Tiwari JN, Kemp KC, Perman JA, Bourlinos AB, Kim KS, Zboril R (2016) Noncovalent functionalization of graphene and graphene oxide for energy materials, biosensing, catalytic, and biomedical applications. Chem Rev 116(9): 5464-5519. https://doi.org/10.1021/acs.chemrev.5b00620\u003c/li\u003e\n\u003cli\u003eAllen MJ, Tung VC, Kaner RB (2010) Honeycomb carbon: a review of graphene. Chem Rev 110(1): 132-145. https://doi.org/10.1021/cr900070d\u003c/li\u003e\n\u003cli\u003eKuila T, Bose S, Khanra P, Mishra AK, Kim NH, Lee JH (2011) Recent advances in graphene-based biosensors. Biosens Bioelectron 26: 4637\u0026ndash;4648. https://doi.org/10.1016/j.bios.2011.05.039\u003c/li\u003e\n\u003cli\u003eWan X, Long G, Huang L, Chen Y (2011) Graphene - a promising material for organic photovoltaic cells. 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New developments in photon and materials research 1:1-20.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"plasma, underwater discharge, graphene, graphene oxide","lastPublishedDoi":"10.21203/rs.3.rs-2607964/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2607964/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis work proposed a novel approach, in which an impulse underwater discharge was used to produce graphene-graphene oxide material in distilled water. The characteristics of this discharge were presented, including electrical parameters, plasma composition, and electron concentration. Graphene-based material produced using this approach can be evenly dispersed in water without the use of a surfactant or stabilizer, and is suitable for storage at room temperature. Ultraviolet\u0026ndash;visible spectroscopy was employed to analyze the optical properties of the graphene-based structures. Scanning electron microscopy was adopted to explore the morphology and size of the particles. The FTIR spectroscopy confirms the formation of graphene oxide. The Raman spectroscopy demonstrates the formation of a graphene-containing multilayer material. The results of this study confirmed that graphene-based material production by impulse underwater discharge is a low-cost, fast, and effective manufacturing method.\u003c/p\u003e","manuscriptTitle":"Synthesis and Characteristics of Graphene-Graphene Oxide Material Obtained by an Underwater Impulse Direct Current Discharge","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-02-22 15:29:21","doi":"10.21203/rs.3.rs-2607964/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"389594e4-35b2-4a30-9242-53dd5bdcd48e","owner":[],"postedDate":"February 22nd, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2023-02-26T12:29:14+00:00","versionOfRecord":[],"versionCreatedAt":"2023-02-22 15:29:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-2607964","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2607964","identity":"rs-2607964","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}