Systems and methods for synthesizing graphene-like nanomaterials using brown's gas plasma in liquid environments

Abstract

Described are systems and methods for synthesizing graphene and graphene-like nanomaterials in liquid environments through plasma interaction with carbon-containing materials, including waste materials. An apparatus for producing graphene-like material directs a plasma torch generated from Brown's gas toward a target comprising a carbon-based material subjected to induce thermal exfoliation. The exfoliated material undergoes ultra-rapid cooling in a liquid medium, facilitating further exfoliation and preventing reaggregation. The apparatus operates as a single-step, chemical-free system without the need for intercalates, solvents, or catalysts, and is designed to function at atmospheric pressure in oxidizing or non-oxidizing inert media. The system enables high-yield, scalable production of graphene and other nanomaterials, while being cost-effective and environmentally sustainable.

Description

Docket BU0127PCT SYSTEMS AND METHODS FOR SYNTHESIZING GRAPHENE-LIKE NANOMATERIALS USING BROWN’S GAS PLASMA IN LIQUID ENVIRONMENTSINVENTORS:Valery SerbezovJason NaydenovSvetlin SerbezovJordan NaydenovKrassimir PetkovNikola ZlatanovBACKGROUND CROSS REFERENCE TO RELATED PATENT APPLICATIONS

[0001] The present application claims priority benefit to co-pending and commonly-assigned U.S. Provisional Patent Application No. 63 / 746,870 and U.S. Provisional Patent Application No. 63 / 746,873, both filed on January 17, 2025 and listing as inventors Valery Serbezov, Jason Naydenov, Svetlin Serbezov, Jordan Naydenov, Krassimir Petkov, and Nikola Zlatanov, which application is herein incorporated by reference as to its entire content. Each reference mentioned herein is incorporated by reference herein in its entirety.A. Technical Field

[0002] The present disclosure relates to nanotechnology and carbon nanomaterials. More particularly, the present disclosure relates to systems and methods for large-scale production of graphene-like materials by using a plasma-based process that employs plasma from Brown’s gas (HHO) to transform carbon-containing materials including waste, such as plastic waste, into graphene nanomaterials, graphene oxide, and reduced graphene oxide for applications in energy storage, electronics, sensors, composite materials, industrial processes, thermal management, and biomedical technologies.B. Background

[0003] Graphene is widely recognized as a revolutionary nanomaterial due to its exceptional properties, which significantly differ from bulk materials. However, the growingDocket BU0127PCT demand for graphene also presents environmental and health risks, primarily due to conventional synthesis methods, the raw materials used, and their associated impacts. To mitigate these risks, clean, sustainable production technologies that utilize waste-derived carbon sources must be developed. Graphene and its derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), are typically synthesized using top-down or bottom-up approaches. The top-down method, which involves graphite exfoliation, is the most common for large-scale production. However, it is expensive, relies on a limited supply of high-purity graphite, and requires multi-step, energy-intensive processes involving harsh chemicals like solvents and oxidants. These factors result in low yields, batch-to-batch variability, and high production costs. Conversely, the bottom-up approach utilizes carbonaceous precursors to synthesize graphene through methods such as Chemical Vapor Deposition (CVD), pyrolysis, epitaxial growth. While promising, these techniques consume high energy, are costly, and often yield non-uniform graphene sheets, limiting their scalability.

[0004] To address these challenges, recent innovations have focused on alternative, low-cost, and environmentally friendly sources for graphene nanomaterials synthesis, such as plastic waste, used tires, biomass (coconut husks, pine bark, sugarcane bagasse), and carbon-rich gases (methane, ethanol, and methanol). Given that plastic waste and used tires are among the most significant global pollutants, their conversion into graphene could provide a sustainable, circular economy solution. According to the United Nations, plastic production exceeded 400 million tons in 2020, is expected to double by 2035, and may reach 1.6 billion tons by 2050, underscoring the urgent need for sustainable waste management.

[0005] Among the most promising methods for graphene nanomaterial synthesis from renewable waste materials are pyrolysis-based techniques and Flash Joule Heating (FJH). Other techniques, such as CVD, pyrolysis with carbonization, and thermal decomposition, are also being explored. However, these methods often suffer from multi-step complexity, the use of toxic chemicals, inconsistent graphene quality, and high energy requirements.

[0006] Plasma-based methods have long been used in nanotechnology, nanoparticle synthesis, coatings, fullerenes, and carbon nanotubes (CNTs). While plasma-based graphene nanomaterial synthesis is promising, existing methods suffer from relatively low yield, high energy consumption, electrode wear, and process variability. Although FJH is a type of plasma process, its reliance on arc discharge with conductive additives and strict energy input parameters makes large-scale graphene production challenging. Recent advancements inDocket BU0127PCT Atmospheric Pressure Microwave Plasma (APMP) have shown potential for converting micro- sized plastic waste into graphene nanomaterials by breaking it down into hydrocarbon gases (methane, ethylene, hydrogen, etc.), which are then plasma-dissociated into graphene. However, such processed still suffer from low yield, high energy consumption, and inconsistent product quality. Current industrial-scale plasma graphene synthesis methods share common limitations, such as material- specific process adaptations, inconsistent graphene quality, low production yields, high energy demand, and environmental concerns.

[0007] Accordingly, what is needed are systems and methods that overcome the limitations of existing methods and devices.SUMMARY OF INVENTION

[0008] The systems and methods herein relate to the synthesis of graphene and graphene-like nanomaterials using a Brown’s gas plasma torch, which enables the conversion of carbon-containing materials, including carbon black from used tires, plastic waste, pulp, and paper, into high-quality graphene nanomaterials, GO, and rGO. In embodiments, industrial-scale graphene production may be achieved through a single-step, ultra-fast process that eliminates the need for externally added chemicals, intercalates, solvents, or catalysts, including metals. Unlike conventional methods that rely on costly and limited graphite sources, embodiments herein utilize post-consumer and recycled carbon materials.

[0009] Various embodiments operate within a temperature range of approximately 350 °C to 3500 °C in either ambient or inert atmosphere, such as argon or nitrogen, taking advantage of the unique properties of HHO plasma, which allows for adaptive interaction with different carbon-containing materials. The HHO plasma torch automatically adjusts its temperature and ionic composition according to the material being processed, eliminating the need for technical adaptations or reconstruction of the device. The resulting graphene yield is dependent on the carbon content of the process material, with high-carbon sources, such as graphite and carbon black with a purity exceeding 99%, producing yields ranging from 85% to 95%. Compared to conventional techniques, such as CVD, Thermal Decomposition with CVD, pyrolysis with carbonization, and FJH, the superior yields and efficiency is achieved, while significantly reducing processing times.

[0010] The method addresses key challenges in nanomaterial production, including selectivity towards specific chemical compounds, morphology control, and scalability for industrial applications. Conventional top-down plasma torch methods require multiple processing steps involving high temperatures, catalytic agents, and controlled vacuum or inertDocket BU0127PCT gas environments. In contrast, the present disclosure integrates a programmable control mechanism utilizing a material- specific interaction within the reaction chamber. This results in efficient shock heating, thermal expansion, and exfoliation of graphene layers, followed by rapid cooling to prevent clustering or unwanted structural changes. The method is further enhanced by an optional ultrasonic treatment that improves exfoliation and dispersion of the synthesized nanomaterials.

[0011] A key advantage is that carbon does not need to be electrically conductive, expanding the range of usable precursor materials. Additionally, the processes are highly efficient in utilizing cracked material species that pass through the reaction chamber, followed by ultra-rapid cooling directly in a liquid medium. The cooling liquid may include distilled water, liquid nitrogen, or solid-phase materials such as dry ice. The synthesis process benefits from cavitation and ultrasonic action within the collection vessel, further enhancing material separation and exfoliation.

[0012] The ultra-fast nature of such methods enables processing times ranging from several tens of seconds to a few minutes, depending on the input material. The duration of plasma interaction is controlled by the flow rate of the carrier gas and the pressure of the HHO flame-forming gas, ensuring precision and consistency in the final product. The process can be operated in a continuous or pulsed mode, allowing for further optimization based on specific application requirements.

[0013] The methods and devices herein enable the synthesis of a broad range of graphene-based materials, including graphene oxide, reduced graphene oxide, porous graphene, and other nanoscale carbon phases and nanocomposites. Unlike classical chemical synthesis of graphene oxide, which involves multiple steps and the use of strong oxidizing agents such as potassium chlorate, nitric acid, and sulfuric acid, various embodiments eliminate hazardous chemicals in an environmentally safe and scalable manner. Additionally, various methods may be used for the synthesis of functionalized graphene nanomaterials via both covalent and non-covalent modifications, incorporating elements such as oxygen, metals, sulfur, phosphorus, and polymers to tailor graphene’s properties for specific applications.

[0014] The resulting graphene HHO material comprises predominantly of sp2-hybridized carbon atoms and exhibits a high degree of structural purity, with at least 85% of the product comprising single-layer or few-layer graphene sheets of 2 to 10 stacked planes. The disclosed methods and devices also facilitate the formation of hybrid nanomaterials, suchDocket BU0127PCT as metal-ceramic nanoparticles and polymer-carbon composites, enabling new functionalities across various industries.

[0015] Potential applications include energy storage systems, including batteries and supercapacitors, as well as electronics, sensors, robotics, composite materials, coatings, and biomedical applications. The unique properties of graphene, such as high electrical and thermal conductivity, mechanical strength, and chemical resistance, make it an ideal candidate for water desalination, thermoelectric devices, ultra-sensitive biosensors, bacterial and viral filtration, and even graphene-enhanced bone regeneration. Additionally, graphene’s use in lightweight, high-strength composite materials is of significant interest to the automotive and aerospace industries. This offers a clean, scalable, and cost-effective alternative to conventional graphene production methods while providing superior product quality and yield. By transforming waste materials into valuable nanomaterials, this technology contributes to sustainable manufacturing practices.

[0016] In some aspects of the disclosure, an apparatus for producing graphene-like material by using Brown’s gas plasma in a liquid environment may comprise a first inlet configured to receive a brown’s gas plasma; a second inlet configured to receive target may comprise a carbon-containing substance, a process chamber may comprise: a nozzle coupled to the first inlet and configured to direct the brown’ s gas plasma toward the target to cause a plasma-material interaction in which a thermal expansion converts at least some of the carbon-containing substance into atomic-level material, a cooling chamber configured to hold a cooling medium, e.g., distilled water that enables a rapid thermal contraction process that converts at least some of the atomic-level material into a graphene-like material may comprise atomic layers, an outlet configured to remove solid-phase graphene-like material, a collection tank configured to receive the graphene-like material and enable a precipitation process to prevent reaggregation, and a filter configured to recover solid-phase graphene-like material from the collection tank.

[0017] In some aspects, the apparatus may comprise electrodes configured to use electrical power to ignite the brown’s gas plasma at substantially atmospheric pressure. The brown’s gas plasma subsequently may comprise maintained at a different pressure. The apparatus may further comprise an ultrasonic chamber configured to enhance liquid-phase exfoliation by generating cavitation effects during the rapid thermal contraction process to enhance exfoliation efficiency and promote uniform dispersion of graphene nanosheets. InDocket BU0127PCT some aspects, the brown’ s gas may be provided substantially at atmospheric pressure, where the graphene-like material is graphene-like nanoscale carbon material.

[0018] In some aspects, of the disclosure a method for producing graphene-like material by using brown’s gas plasma may comprise, in a liquid-phase environment, exposing a target may comprise a carbon-containing substance to a brown’s gas plasma to cause a plasma-material interaction in which a thermal expansion converts at least some of the carbon-containing substance into atomic-level material. The liquid-phase environment may comprise a cooling medium that, in a rapid thermal contraction process, converts at least some of the atomic-level material into a graphene-like material may comprise atomic layers. The method may further comprise moving the target relative to a plasma interaction zone to regulate the plasma-material interaction and facilitate a controlled carbonization, using a precipitation process to prevent reaggregation, and using a solid-liquid separation process to recover solid-phase graphene-like material from the cooling medium. Moving the target may comprise rotating the target around an axis of the target. The method may further comprise directing the brown’s gas plasma at an angle toward the target to cause the plasma-material interaction. The brown’s gas plasma may be maintained in a pulsed power mode to enhance exfoliation

[0019] In some aspects, the method may comprise applying ultrasonic energy to the cooling medium to cause cavitation effects in the solid-phase graphene-like material that enhance liquid-phase exfoliation of the carbon-containing substance, which may comprise a polymer precursor, which may comprise at least one of polystyrene and polyethylene terephthalate. In some aspects, the brown’ s gas may be ignited by igniting a gas mixture of hydrogen and oxygen at substantially atmospheric pressure and may be maintained at a different pressure; and the cooling medium may be continuously replenished to maintain a controlled temperature during the rapid thermal contraction process.Docket BU0127PCT BRIEF DESCRIPTION OF THE DRAWINGS

[0020] References will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments. Items in the figures are not to scale.

[0021] FIG. 1 is a schematic representation of an HHO-based process for synthesizing graphene and graphene-like materials in a liquid environment, according to various embodiments of the present disclosure.

[0022] FIG. 2A - FIG. 2C depict SEM micrographs of rGO synthesized from polyethylene terephthalate (PET) polymer using an HHO process in liquid environment, according to various embodiments of the present disclosure.

[0023] FIG. 3A - FIG. 3C depict SEM micrographs of rGO synthesized from polystyrene (PS) polymer using an HHO process in liquid environment, according to various embodiments of the present disclosure.

[0024] FIG. 4A - FIG. 4C depict SEM micrographs of rGO synthesized simultaneous from PS and polyethylene terephthalate (PET) polymer using an HHO process in liquid environment, according to various embodiments of the present disclosure.

[0025] FIG. 5A depicts Raman shifts of rGraphene oxide synthesized from PET using a process in a liquid environment, according to various embodiments of the present disclosure.

[0026] FIG. 5B depicts Raman shifts of rGraphene oxide synthesized from PS-PET using a process in a liquid environment, according to various embodiments of the present disclosure.

[0027] FIG. 6 is a flowchart of an exemplary process for producing graphene-like material by using Brown’s gas plasma in liquid environment, according to various embodiments of the present disclosure.Docket BU0127PCT DETAILED DESCRIPTION OF EMBODIMENTS

[0028] In the following description, for purposes of explanation, specific details are set forth in order to provide an understanding of the disclosure. It will be apparent, however, to one skilled in the art that the disclosure can be practiced without these details. Furthermore, one skilled in the art will recognize that embodiments of the present disclosure, described below, may be implemented in a variety of ways, such as a process, an apparatus, a system / device, or a method on a tangible computer-readable medium.

[0029] Components, or modules, shown in diagrams are illustrative of exemplary embodiments of the disclosure and are meant to avoid obscuring the disclosure. It shall be understood that throughout this discussion components may be described as separate functional units, which may comprise sub-units, but those skilled in the art will recognize that various components, or portions thereof, may be divided into separate components or may be integrated, including, for example, being in a single system or component. It should be noted that functions or operations discussed herein may be implemented as components. Components may be implemented in software, hardware, or a combination thereof.

[0030] Furthermore, connections between components or systems within the figures are not intended to be limited to direct connections. Rather, data between these components may be modified, re-formatted, or otherwise changed by intermediary components. Also, additional or fewer connections may be used. It shall also be noted that the terms “coupled,” “connected,” “communicatively coupled,” “interfacing,” “interface,” or any of their derivatives shall be understood to include direct connections, indirect connections through one or more intermediary devices, and wireless connections. It shall also be noted that any communication, such as a signal, response, reply, acknowledgment, message, query, etc., may comprise one or more exchanges of information.

[0031] Reference in the specification to “one or more embodiments,” “preferred embodiment,” “an embodiment,” “embodiments,” or the like means that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the disclosure and may be in more than one embodiment. Also, the appearances of the above-noted phrases in various places in the specification do not necessarily all refer to the same embodiment or embodiments.

[0032] The use of certain terms in various places in the specification is for illustration and should not be construed as limiting. The terms “include,” “including,” “comprise,” “comprising,” and any of their variants shall be understood to be open terms, and anyDocket BU0127PCT examples or lists of items are provided by way of illustration and shall not be used to limit the scope of this disclosure.

[0033] Any headings used herein are for organizational purposes only and shall not be used to limit the scope of the description or the claims. Each reference / document mentioned in this patent document is incorporated by reference herein in its entirety.

[0034] The present disclosure describes an industrial-scale process for synthesizing high-quality graphene and graphene-like nanosheets through the interaction of a Brown gas (HHO) plasma torch with carbon-containing materials. The synthesis process may occur in three distinct stages: 1) thermal decomposition of a carbon-containing substance within a reaction vessel, 2) rapid cooling of the dissociated material, leading to the nucleation of graphene structures, and 3) the controlled growth of these nuclei into few-layer graphene and graphene-like nanosheets.

[0035] As used herein, the term “carbon-containing substance” refers to any carbon-containing compound or substance composed primarily of carbon. The terms “plasma,” “HHO plasma torch,” and “plasma burner” may be used interchangeably to describe the high-energy ionized gas system that facilitates the synthesis process. The term “thermal zone” refers to the region where the plasma achieves a near or complete thermodynamic equilibrium.

[0036] The terms “graphene-like nanomaterials” and “graphene nanosheets” refer to crumpled graphene nanosheets having one or more layers of sp2-bonded carbon atoms arranged in a honeycomb lattice. Stacked nanosheets exhibiting curled, curved, or buckled morphologies result in a 3D structure. Depending on their specific characteristics, the synthesized materials may be referred to as “graphene nanoplatelets,” “graphene nanoflakes,” “few-layers graphene,” or simply “graphene.”

[0037] A fundamental principle in nanomaterial synthesis is the rapid introduction of energy into the system, followed by immediate cooling to prevent reaggregation. Systems and methods disclosed herein utilize a high-energy plasma generated from Brown’s gas, which is produced via water electrolysis. The Brown’s gas plasma interacts with carbon-based waste materials, such as charcoal, carbon black from used tires, and plastic waste, thus resulting in graphene formation through high-temperature exfoliation, followed by rapid thermal contraction.

[0038] Brown’s gas, named after researcher Yuli Brown, is generated by electrolysis, splitting water into hydrogen and oxygen. Unlike conventional fuels, Brown’s gas plasma hasDocket BU0127PCT unique properties, including high ionization, electrical conductivity, and the ability to sustain combustion even in vacuum and underwater. It has a high energy density (-15,000 J / L), comparable to laser-material interaction; can reach temperatures of up to 4000 °C. Additionally, Brown’s gas is implosive in nature, producing only water vapor as a byproduct, which makes it an environmentally safe and non-polluting energy source.

[0039] The Brown’s gas plasma torch adapts to different carbon-containing materials, enabling effectively exfoliation of graphene layers from waste materials without requiring complex process adjustments. Additionally, this eliminates the need for harsh chemicals and catalysts, reduces batch-to-batch inconsistencies, and significantly lowers overall energy consumption, facilitating a single-step, high-yield graphene production process.

[0040] It shall be noted that while embodiments described herein are framed in the context of atmospheric environments, one skilled in the art will recognize that the concepts of the present disclosure are not so limited and may equally be used under superatmospheric, underpressure, or vacuum-controlled process conditions.

[0041] FIG. 1 is a schematic representation of an HHO-based process for synthesizing graphene and graphene-like materials in a liquid environment, according to various embodiments of the present disclosure. In embodiments, plasma is generated by an HHO generator 100, whose process chamber 2 receives Brown’s gas 11 through nozzle (e.g., 3); cooling medium 5; plasma 7, which may be configured as a distributed plasma burner; one or more inlets 5 and outlet 9 for cooling medium 5; ultrasonic chamber 10; and storage tank 15, which may be positioned in sonication device 10.

[0042] In embodiments, device 100 holds to-be-processed target material 1 comprising any suitable carbon-containing substance. As depicted in the example in FIG. 1, target material 1 is implemented in the form of a cylindrical rod that is sealed against process chamber 2.

[0043] Process chamber 2 may be constructed from any suitable materials and designed in various geometries, including cylindrical or conical shapes. It is noted that while FIG. 1 depicts plasma torches 7 as positioned at a 90 °C angle relative to the surfaces of target 1 , this is not intended as a limitation on the scope of the present disclosure as alternative configurations, including angled or multi-directional orientations of torch 7 are envisioned. In embodiments, the angle of incidence between plasma torch 7 and target 1 and / or their relative locations may be manually or automatically adjustable, e.g., by a programmable device (not shown).Docket BU0127PCT

[0044] In operation, target 1 undergoes rotational movements around the z-axis and translation movements along the same axis within device 100. Target 1 may be mounted at or on a movable carrier (not shown) to facilitate its translation and / or rotation motion. The rotational frequency of target 1 may range from about 0.02 Hz to 3000 Hz. The carbon-containing substance used in target 1 may be solid-state, e.g., graphite, polymer, carbon black, or combination of materials. Polymer material may be obtained from compressed plastic waste, while carbon black may be obtained from processed used tires. Process chamber 2 may be constructed from heat-resistant materials, such as metals, ceramics, or heat-resistant glass for visualization of process. It may also be designed having any arbitrary shape.

[0045] In embodiments, plasma torch (or burner) 7 provides a Brown’s gas plasma to generator 100. A gas discharge may be initiated through a dielectric, such as a dielectric wall (not shown), utilizing inductive and / or capacitive coupling mechanisms. A suitable power source (also not shown) may operate in continuous or pulsed mode, at one or more frequencies.

[0046] In embodiments, plasma torch 7 may be ignited before process chamber 2 is filled with cooling medium 5 and before target 1 is inserted into process chamber 2. During operation, target 1 undergoes rapid heating by impact with plasma 7, causing structural exfoliation of the atomic lattice due to thermal expansion. In embodiments, a localized shockheating process heats target 1 without significantly heating cooling medium 5. This is a result of the unique properties of Brown’s gas plasma, which selectively heats the material at the point of interaction. At this interaction zone, micro-bubbles are formed and can be observed together with the separation of micro-particles from target 1. The micro-bubbles may be gaseous in nature and contribute to the cooling of the separated micro-particles.

[0047] In embodiments, the temperature of the heated zone where plasma torch 7 interacts with the material of target 1 ranges from 700 °C to 3200 °C. In embodiments, the temperature may dynamically self-adjust in response to changes in the structure of the material being processed. In embodiments, rapid thermal contraction occurs through liquid shock cooling of the processed material in cooling medium 5 within processing chamber 2, to carry out additional exfoliation and stabilization graphene-like material comprising atomic layers. Cooling medium 5 may be any suitable cooling liquid, such as distilled water or other cooling substances. Unheated cooling medium 5 rapidly cools and stabilizes exfoliated nanomaterials 6, which exhibit a graphite-like nature. During the high-energy plasmaDocket BU0127PCT interaction with target 1, combined with thermal shock cooling, intensive carbonization, graphitization, and exfoliation processes may occur, particularly when processing pressed polymer materials.

[0048] In embodiments, thermal shock cooling prevents re aggregation and stabilizes the synthesized graphene-like nanomaterials. The process for synthesis graphene-like nanomaterials may also be enhanced by continuously replenishing cooling medium 5, which enters process chamber 2 through inlet 8 and exits through outlet 9. A suitable replenishment rate may vary, e.g., from several hundred milliliters to several liters per cycle, depending on the dimensions of process chamber 2 and target l’s composition, dimensions, and its movement relative to plasma torch 7. Advantageously, this setup supports continuous operation, enabling a 24-hour production cycle. Processing may be halted depending on the goals of the synthesis of complex nanocomposite materials, e.g., when replacing target 1, introducing additional solvents, or modifying cooling medium 5.

[0049] In embodiments, the temperature of the modified viscous carbon-clustered solution may be controlled using a cooling bath or product tank 15, where processed material 6 may be stored. Crude carbon micro- nano-materials may be continuously collected from outlet flow 9. Exfoliated nanomaterial 6 may consist solely of carbon nanostructure, as no additional materials or contaminants are involved introduces during processing. Therefore, it is not necessary to employ further purification methods, such as high- temperature hydrogen treatment, hydrothermal treatment, microfiltration, solvent extraction, acid treatment, or air oxidation. Advantageously, this preserves the structural integrity of the synthesized materials.

[0050] In embodiments, exfoliated carbon material 6 within cooling medium 5 may undergo additional processing, such as mechanical agitation, sonication, or cavitation, to further separate graphene-like layers and prevent reaggregation. In the example depicted in FIG. 1, cooling medium 5 enters sonication device 10, which facilitates liquid-phase exfoliation. In embodiments, sonication device 10 contributes to efficient, fine, and thorough dispersion by means of cavitation-driven exfoliation of the processed material.

[0051] Sonication methods, such as treatment in distillated water, enable the synthesis of high-yield nanomaterials in an environmentally safe manner, eliminating the need for hazardous chemicals. In applications where sonication device 10 is implemented as an ultrasonic device, it may operate at a frequency range from several tens of kilohertz to several megahertz, e.g., from 15 kHz to 1.5 MHz, at any desired power level. The sonication durationDocket BU0127PCT may be adjusted in accordance with other parameters of device 10, such as power, frequency, viscosity, and temperature.

[0052] Once exfoliated, the graphene-like nanomaterial enters tank 15, where it is allowed to settle, e.g., at ambient temperature for about 15-30 minutes allowing micro-sized graphite to precipitate. The resulting aqueous suspension may be separated into distinct phases through a decantation process. A first purification step may involve filtration using fine-mesh filters (e.g., filter paper) to remove coarse micro-sized particulates. The precipitate mainly comprises micro-sized graphite material and liquid-phase graphene-like nanosized material, including graphene sheets, GO, and rGO.

[0053] Further purification may be achieved by controlled evaporation of residual water from the aqueous suspension at temperatures around 40 °C to 60 °C to yield solid-phase material, which represents the synthesized graphene-like nanomaterials. In embodiments, subsequent processing steps, such as centrifugation, may be applied to further separate nanomaterials and enhance their quality.

[0054] EXAMPLES

[0055] High-quality graphene typically comprise 10 or fewer atomic layers, with particle thicknesses ranging from 0.5 nm to 10 nm and widths of 50 nm or larger. When analyzed using Raman spectroscopy with an incident laser wavelength of 633 nm, these graphene structures exhibit a characteristic D, G, and 2D bands, located at about 1333 cm1, 1584 cm1, 2661 cm1, respectively. Graphene oxide is an oxygen-functionalized form of graphene, structured as a two-dimensional (2D) material with a hexagonal carbon lattice, typically derived from oxidized graphite or other carbon-rich precursors. Reduced graphene oxide is a chemically or thermally treated variant of GO, in which the oxygen content is significantly reduced, restoring properties similar to pristine graphene. The ID / IC ratio, commonly used to evaluate defect density in graphene, may be less reliable when applied to GO and rGO due to variations in oxidation levels.

[0056] The examples provided herein are based on experimental methods and implemented on devices such as the one illustrated in FIG. 1. The characterization and analysis of the synthesized graphene-like nanomaterials was conducted using the following techniques:

[0057] - The physical structure was characterized using X-ray diffraction (XRD) and a Panalytical Empyrean diffractometer. Measurements were performed using powder X-ray diffraction geometry scans.Docket BU0127PCT

[0058] - Surface morphology of the product samples was examined using Scanning Electron Microscopy (SEM) in both secondary electron and backscattering electron imaging (SE and BE respectively) mode. Elemental composition analysis was performed using Energy-dispersive X-ray analysis (EDX).

[0059] - Non-destructive chemical analysis, which provides detailed information about chemical structure, phase and polymorphy, crystallinity, and molecular interaction, was performed using Raman Spectroscopy using a micro-Raman visible spectrometer equipped with a Peltier-cooled CCD detector and a He-Ne laser (633 nm, 0.5 mW).

[0060] - The elemental composition across the surface or in-depth profiling of synthesized materials was measured using X-ray photoelectron spectroscopy (XPS) and non-monochromatized Al Ka (1486.6 eV) radiation in an electron spectrometer under lx 10sPa base pressure. The spectrometer resolution was calculated from the Ag 3d5 / 2line an analyzer transmission energy of 20 eV. The full with at half maximum (FWHM) on this line is 1 eV. The spectrometer was calibrated against the using Ag 4f? / 2line (84 eV) and the sample’s charge was estimated from the Cis (285 eV) spectra from natural hydrocarbon contamination on the surface. The accuracy of the binding energies (BEs) measured was 0.2 eV.

[0061] In embodiments, carbon-containing material 2 comprises polymers, such as polystyrene (PS), polyethylene terephthalate (PET), or a mixture thereof. These polymers are widely used in industrial and consumer applications, including foam packaging, disposable food containers, electronics, toys, liquid storage containers, food containers, and so on. Annually, over 350 million tons of PET plastic waste and 20 million tons of PS plastic waste are generated globally, posing increasing challenges for plastic waste management.

[0062] PS and PET contain carbon in significant proportions, with PS comprising about 90% carbon and PET about 60%. Their precursors are suitable for synthesis of low-cost, high-performance carbon and graphite nanomaterials.

[0063] It is noted that the experiments and results herein are provided by way of illustration and were performed under specific conditions, e.g., carried out using a device similar to that described in FIG. 1 and using a specific embodiment or embodiments; accordingly, neither these experiments nor their results shall be used to limit the scope of the disclosure of the current patent document.

[0064] Target 1 was implemented as a cylindrical rod manufactured mainly from ground waste polymers material and pressed polymers particles comprising: (1) PS, (2) PET, and (3) a 50% / 50% mixture of both. Each of the three cylindrical rods had dimensions of 15Docket BU0127PCT mm in diameter and 40 mm in length. The size of the ground polymer particles was in the range of about 0.5 mm - 0.8 mm. Process chamber 2 was cylindrical in shape and made from heat-resistant glass having a volume of 2000 ml. An aluminum (Al) cover was mounted on the upper part of the chamber, containing openings for securing rod 1 , an inlet 8 for distilled water 5, which filled reaction chamber 2. Holes were also drilled into process chamber 2 to accommodate plasma nozzles 3. The lower part of reaction chamber 2 comprised an opening for outlet 9 to direct the outflow of modified distilled water into tank 15, which collected synthesized carbon-like nanomaterial 6. Tank 15 was positioned within ultrasonic device 10.

[0065] In operation, cylindrical rod 1 set onto rotational and translational motion by an electric motor (not shown) located outside of chamber 2. The process started with the ignition of an HHO plasma gas in plasma nozzle 3.

[0066] The plasma was ignited through an arc discharge at atmospheric pressure or by directed flame from a gas burner. Once the HHO gas plasma was ignited, reaction chamber 2 was filled with distilled water 5 through water inlet 8. Following this, cylindrical rod 1 was rotated at a controlled speed, adjustable from 10 rpm to 200 rpm via the electric motor. The immersion of cylindrical rod 1 facilitated the interaction with HHO plasma torch 7. Due to the high temperatures developed during plasma exposure and the duration of localized heating, the polymers underwent micro-particle separation, followed by carbonization and graphitization. The Brown’s gas plasma has the property of not heating the water but only carbon-containing material-the rod. The temperature in the hot zone of the rod was maintained between 2500 °C to 3000 °C, with a process time between 1 minute and 15 minutes. During this process, exfoliation 6 of the graphitized polymer material(s) and synthesis of graphene-like nanomaterials were realized.

[0067] In embodiments, the process could be operated continuously by continuously repositioning plasma torch 7 over different sections of cylindrical rod 1 and refreshing the supply of distilled water 5, which flowed through outlet 9 into storage tank 15. Alternatively, the process could be pulsed.

[0068] In embodiments, the efficiency of the process may be further enhanced by the creation of vortices around the torch-rod interaction zone to facilitate improved exfoliation and material delamination. Gaseous byproducts, primarily hydrogen (H2), CH2, carbon dioxide (CO2), and trace amounts of carbon monoxide (CO), were released from the polymers, mixed with water 5, and removed from reaction chamber 2. Additionally, water 5 may be processed through filters to recover green hydrogen.Docket BU0127PCT

[0069] The resulting exfoliated graphene-like material was collected in storage tank 15. Additionally, process chamber 2 containing cooling medium 5 may be integrated with ultrasonic bath 10 to induce cavitation effects to enhance liquid-phase exfoliation and further improve the yield and quality of the final graphene product.The synthesized material composed high-quality graphene-like nanomaterials, nanosheets as confirmed by SEM micrographs presented in FIG. 2A - FIG. 2C, FIG. 3A - FIG. 3C, and FIG. 4A - FIG. 4C.

[0070] The images, captures using high-resolution techniques with optimal contrast methods and depth of field, provide detailed visualization of the produced nanomaterials.

[0071] FIG. 2A - FIG. 2C depict SEM micrographs of rGO synthesized from polyethylene terephthalate (PET) polymer using an HHO process in liquid environment, according to various embodiments of the present disclosure. FIG. 3A - FIG. 3C depict SEM micrographs of rGO synthesized from polystyrene (PS) polymer using an HHO process in liquid environment, according to various embodiments of the present disclosure. FIG. 4A - FIG. 4C depict SEM micrographs of rGO synthesized simultaneous from PS and polyethylene terephthalate (PET) polymer using an HHO process in liquid environment, according to various embodiments of the present disclosure.

[0072] The images for FIG. 2B, FIG. 2C, FIG. 3B, FIG. 3C, and FIG. 4B, FIG. 4C reveal the characteristic layered structure of graphene nanomaterials, demonstrating the successful transformation of polymers materials through carbonization, graphitization and exfoliation in a single technological step. It is noted that graphene nanoplates contain exhibited layers, with the number of layers decreasing as the carbon content increased. The highest degree of exfoliation was observed in the PET+PS combination, indicating superior graphitization and nanomaterial formation.

[0073] FIG. 5A depicts Raman shifts of rGraphene oxide synthesized from PET using a process in a liquid environment, according to various embodiments of the present disclosure. Plot 502 illustrates the Raman shift of the original material PET; plot 504 illustrates the Raman shift at a temperature of 2200 °C; and plot 506 illustrates the Raman shift at a temperature of 2500°C, which indicates a higher reduction of GO.

[0074] FIG. 5B depicts Raman shifts of rGraphene oxide synthesized from PS-PET using a process in a liquid environment, according to various embodiments of the present disclosure. Plot 550 illustrates the Raman shift at a temperature of 2200 °C; and plot 552 illustrates the Raman shift at a temperature of 3000 °C.Docket BU0127PCT

[0075] FIG. 6 is a flowchart of an exemplary process for producing graphene-like material by using Brown’s gas plasma in liquid environment, according to various embodiments of the present disclosure. Process 600 may start at step 602 when, in a liquidphase environment, a Brown’s gas plasma interacts with a carbon-containing substance, causing a thermal expansion that converts at least some of the carbon-containing substance into atomic-level material.

[0076] At step 604, a rapid thermal contraction process uses a cooling medium to convert at least some of the atomic-level material into a graphene-like material comprising atomic layers.

[0077] In embodiments, at step 606, the target is moved relative to the Brown’s gas plasma to regulate the plasma-material interaction and facilitate a controlled carbonization.

[0078] At step 608, a precipitation process may be used to inhibit reaggregation of the graphene-like material, thereby preserving a nanoscale structure.

[0079] Finally, at step 610, a solid- liquid separation process is used to extract and recover solid-phase graphene-like material from the cooling medium.

[0080] One skilled in the art shall recognize that: (1) certain steps may optionally be performed; (2) steps may not be limited to the specific order set forth herein; (3) certain steps may be performed in different orders; and (4) certain steps may be done concurrently.

[0081] Overall, the present disclosure demonstrates that Brown’ s gas plasma interaction with carbon-containing waste materials, such as plastic waste and carbon black, is an efficient method for synthesizing graphene, graphene oxide, and reduced graphene oxide with a substantial level of exfoliation, oxidation, and sheet- like structure in liquid-phase processes. By adjusting synthesis parameters, such as reaction time, temperature, and oxidizing agent concentration, it is possible to tailor the physical and chemical properties of the resulting graphene-like nanomaterials, while maintaining an environmentally clean synthesis approach.

[0082] It will be appreciated by those skilled in the art that the preceding examples and embodiments are exemplary and not limiting to the scope of the present disclosure. It is intended that all permutations, enhancements, equivalents, combinations, and improvements thereto that are apparent to those skilled in the art upon a reading of the specification and a study of the drawings are included within the true spirit and scope of the present disclosure. It shall also be noted that elements of any claims may be arranged differently including having multiple dependencies, configurations, and combinations.

Claims

Docket BU0127PCT CLAIMS WHAT IS CLAIMED IS:

1. An apparatus for producing graphene- like material by using Brown’s gas plasma in a liquid environment, the apparatus comprising:a first inlet configured to receive a Brown’s gas plasma;a second inlet configured to receive target comprising a carbon-containing substance;a process chamber comprising:a nozzle coupled to the first inlet and configured to direct the Brown’s gas plasma toward the target to cause a plasma-material interaction in which a thermal expansion converts at least some of the carbon-containing substance into atomic-level material;a cooling chamber configured to hold a cooling medium that enables a rapid thermal contraction process that converts at least some of the atomic-level material into a graphene-like material comprising atomic layers;a collection tank configured to receive the graphene-like material and enable a precipitation process to prevent reaggregation; anda filter configured to recover solid-phase graphene-like material from the collection tank.

2. The apparatus of claim 1, further comprising electrodes configured to use electrical power to ignite the Brown’s gas plasma at substantially atmospheric pressure, the Brown’s gas plasma subsequently being maintained at a different pressure.

3. The apparatus of claim 1, further comprising an ultrasonic chamber configured to enhance liquid-phase exfoliation by generating cavitation effects during the rapid thermal contraction process to enhance exfoliation efficiency and promote uniform dispersion of graphene nanosheets.

4. The apparatus of claim 1, wherein the Brown’s gas is provided substantially at atmospheric pressure, and wherein the graphene-like material is graphene-like nanoscale carbon material.

5. The apparatus of claim 1 , wherein the cooling medium comprises distilled water.

6. The apparatus of claim 1, wherein the process chamber comprises an outlet configured to remove solid-phase graphene-like material from the process chamber.Docket BU0127PCT 7. A method for producing graphene- like material by using Brown’s gas plasma, the method comprising:in a liquid-phase environment, exposing a target comprising a carbon-containing substance to a Brown’s gas plasma to cause a plasma-material interaction in which a thermal expansion converts at least some of the carbon- containing substance into atomic-level material, the liquid-phase environment comprising a cooling medium that, in a rapid thermal contraction process, converts at least some of the atomic-level material into a graphene-like material comprising atomic layers;moving the target relative to a plasma interaction zone to regulate the plasmamaterial interaction and facilitate a controlled carbonization; using a precipitation process to prevent reaggregation; andusing a solid-liquid separation process to recover solid-phase graphene-like material from the cooling medium.

8. The method of claim 7, further comprising applying ultrasonic energy to the cooling medium to cause cavitation effects in the solid-phase graphene-like material that enhance liquid-phase exfoliation of the carbon-containing substance.

9. The method of claim 7, wherein the Brown’s gas is ignited by igniting a gas mixture of hydrogen and oxygen at substantially atmospheric pressure and is maintained at a different pressure.

10. The method of claim 7, wherein moving the target comprises rotating the target around an axis of the target.

11. The method of claim 7, further comprising directing the Brown’s gas plasma at an angle toward the target to cause the plasma-material interaction.

12. The method of claim 7, wherein the Brown’s gas plasma is maintained in a pulsed power mode to enhance exfoliation.

13. The method of claim 7, wherein the cooling medium is continuously replenished to maintain a controlled temperature during the rapid thermal contraction process.

14. The method of claim 7, wherein the carbon-containing substance comprises a polymer precursor.

15. The method of claim 14, wherein the polymer precursor comprises at least one of polystyrene and polyethylene terephthalate.

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