Scaled flash joule heating reactor systems and methods of using same

Abstract

Systems and methods utilizing a flash Joule heating reactor, and more particularly, systems and methods utilizing a large-scale flash Joule heating reactor of large masses of feedstock. For instance, the present systems and method can be utilized for the (a) synthesis of graphene by flash Joule heating, (b) synthesis of carbides by flash Joule, (c) flash 1D materials from plastic waste, (d) flash-within-flash (FWF) Joule heating, (e) flash Joule heating of glass fiber reinforced plastic (GFRP) to make SiC, and (f) high-energy flash Joule heating synthesis methods.

Description

Attorney Docket No.: 072174-06701SCALED FLASH JOULE HEATING REACTOR SYSTEMS AND METHODS OF USING SAME CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

[0001] The application claims priority to U. S. Patent Appl. Serial No. 63 / 645,535, filed May 10, 2024, entitled “Scaled Flash Joule Heating Reaction Systems and Methods of Using Same,” which patent application is commonly owned by the owner of the present invention and is incorporated herein in its entirety.TECHNICAL FIELD

[0002] The present invention relates to systems and methods utilizing a flash Joule heating reactor, and more particularly, systems and methods utilizing a large-scale flash Joule heating reactor of large masses of feedstock.GOVERNMENT INTEREST

[0003] This invention was made with government support under Grant No. FA9550-22-1-0526, awarded by the Air Force Office of Scientific Research, and Grant No. W912HZ-21-2-0050, awarded by the Engineer Research and Development Center. The government has certain rights in the invention.BACKGROUND

[0004] Flash Joule heating (FJH) is a technique by which electric current rapidly travels through a resistive medium, heating the sample on the millisecond to second timescale. [Luong 2020}. FJH has been used in a wide array of applications including solid state synthesis [Choi 2024 Dong Q 2022}, especially of graphene [Stanford 2020}, ceramics [Wang 2020}, inorganics [Choi 2020,' Chen G 2022}, high-entropy nanoparticles [Cai 2024}, and their selfencapsulation [Wang 2024}, wet synthesis [Zhang 2023}, waste material upcycling [Advincula 202L, Deng 202 J; Chen 2023,' Wyss 2023; Cheng I 2024}, and even soil remediation [Deng 2023}, up to kilogram scales [Eddy 2023}. Conventional FJH uses a capacitor bank discharge to rapidly heat feedstocks up to or exceeding 3000 K. Systems and methods for flash JouleAttorney Docket No.: 072174-06701 heating are disclosed and taught, for example, in Tour ‘967 PCT Application, Tour ‘030 PCT Application, Tour ‘000 PCT Application, Tour ‘780 PCT Application, Tour ‘588 PCT Application, and Tour ‘481 PCT Application. FJH systems are typically custom-designed, laboratory-made, and thus each system is often entirely different. [Luong 2020,' Eddy 2023,' Dong S 2022,' Wyss I 2022}. These differences in FJH systems present a barrier to simple reproducibility across laboratories, since even small differences in system power, energy capacity, or time constant can significantly change the reaction heating profile. [Eddy 2024],

[0005] Furthermore, the assembly of even gram-scale FJH systems often requires tens of thousands of dollars, personnel experienced in the assembly of high-voltage electrical equipment, and months of assembly prior to use. [Zhu 2024}. Capacitor-based FJH systems feature comparatively low-temperature controllability [Luong 2020}, are limited to reactions <10 s [Stanford 2020}, are difficult to scale cost-effectively, and can suffer damage to the system when the resistance of the feedstock is too low [Choi 2024}. Finally, intense optimization work must be performed anew for every FJH system for every sample type and size in order to control reaction temperature within -100 °C [Sattari 2023,' Beckham 2022}, such that optimization performed on one system does not easily translate to others.SUMMARY OF THE INVENTION

[0006] The present invention relates to systems and methods utilizing a flash Joule heating reactor, and more particularly, systems and methods utilizing a large-scale flash Joule heating reactor of large masses of feedstock.

[0007] In embodiments of the present invention, a new reactor system is used to achieve large scale flash Joule heating of a large mass of feedstock to produce graphene, turbostratic graphene, ordered graphene, ordered graphite, graphite, carbides, carbyne, carbon nanotubes (CNTs), carbon nanofibers, bamboo-like carbon nanotubes, boron nitride nanotubes, boron nitride carbide nanotubes, boron phosphide nanotubes, boride whiskers, carbide whiskers,Attorney Docket No.: 072174-06701 nitride whiskers, phosphide whiskers, inorganic whiskers, BxNyCz whiskers, BxNyCz nanotubes, silicon carbide whiskers, boron carbide whiskers, bottle-brush nanotubes, bottlebrush fibers, nanotubes templated on carbon fiber, nanowhiskers templated on carbon fiber, p-block metal dichalcogenides (PMDs), transition metal dichalcogenides (TMDs), onedimensional PMDs, one-dimensional TMDs, MoS2nanotubes, WS2nanotubes, inorganic compounds, inorganic complexes, organometallic compounds, metal carbides, MAXs, MXenes, flash 1D materials, and combinations thereof.

[0008] In general, in one embodiment, the invention features a method that includes adding a conductive medium in a thermally resistive reaction vessel. A first electrode and a second electrode are positioned in the conductive medium within the thermally resistive reaction vessel. The method further includes performing a flash Joule heating process. A voltage is applied across the first electrode and the second electrode to enable electric current to flow between the first electrode and the second electrode and through the conductive medium. The conductive medium is not under compression within the thermally resistive reaction vessel during the flash Joule process.

[0009] Implementations of the invention can include one or more of the following features:

[0010] The conductive medium can include a carbon material.

[0011] The conductive medium can have a conductivity in a range between 10-3S / cm and 102S / cm.

[0012] The conductivity of the conductive medium is in the range between 2 x 10-2S / cm and 102S / cm.

[0013] The method can further include performing a mixing process to mix the conductive medium during the flash Joule heating process.

[0014] The mixing process can be selecting from the group consisting of vibrating processes, shaking processes, turning processes, rotating platform processes, stirring processes, mobileAttorney Docket No.: 072174-06701 electrode processes, and combinations thereof.

[0015] The performing of the mixing process can provide for uniform heating over the conductive medium.

[0016] The voltage can be applied using a heating method selected from the group consisting of (a) utilizing a power supply in series, (b) utilizing a power supply in parallel, (b) utilizing exactly one pair of electrodes, (d) utilizing more than one pair of electrodes, (e) utilizing a main electrode and at least two more satellite electrodes, wherein the first electrode that is the main electrode and the second electrode is one of the at least two satellite electrodes, and (f) combinations thereof.

[0017] The voltage applied can be a constant voltage.

[0018] The voltage applied can include one or more voltage pulses applied across the first electrode and the second electrode.

[0019] The voltage pulse can be performed using a source selected from the group consisting of unmodulated DC power sources, pulse-width modulated DC power sources, AC power sources, unmodulated DC capacitor pulses, pulse-width modulated DC capacitor pulses, and combinations thereof.

[0020] The voltage be sufficient to impedance-match the resistance of the feedstock.

[0021] The first electrode and the second electrode can be a pair of arc welder electrodes.

[0022] The first electrode can include a first material selected from the group consisting of graphite, tungsten carbide, silicon carbide, lanthanated tungsten, steel, iron, graphene, metals, metallic alloys, metal composites and / or alloys, and combinations thereof. The second electrode can include a second material selected from the group consisting of graphite, tungsten carbide, silicon carbide, lanthanated tungsten, steel, iron, graphene, metals, metallic alloys, metal composites, and / or alloys, and combinations thereof.

[0023] The first material and the second material can be the same material.Attorney Docket No.: 072174-06701

[0024] The first material and the second material can be different materials.

[0025] The method can produce a product as a result of the flash Joule heating process. The product can be selected from the group consisting of graphene, turbostratic graphene, ordered graphene, ordered graphite, graphite, carbides, carbyne, carbon nanotubes (CNTs), carbon nanofibers, bamboo-like carbon nanotubes, boron nitride nanotubes, boron nitride carbide nanotubes, boron phosphide nanotubes, boride whiskers, carbide whiskers, nitride whiskers, phosphide whiskers, inorganic whiskers, BxNyCz whiskers, BxNyCz nanotubes, silicon carbide whiskers, boron carbide whiskers, bottle-brush nanotubes, bottle-brush fibers, nanotubes templated on carbon fiber, nanowhiskers templated on carbon fiber, p-block metal dichalcogenides (PMDs), transition metal dichalcogenides (TMDs), one-dimensional PMDs, one-dimensional TMDs, MoS2nanotubes, WS2nanotubes, inorganic compounds, inorganic complexes, organometallic compounds, metal carbides, MAXs, MXenes, flash ID materials, and combinations thereof.

[0026] The method can also a produce gaseous product as a result of the flash Joule heating process. The method can further include capturing and recovering the gaseous product. The gaseous product may be selected from the group consisting of hydrogen (H2), carbon monoxide, syngas (hydrogen and carbon monoxide), carbon dioxide, alkane gases (CH4, C2H6, C3H8, etc.), hydrocarbon gases, oxygenated hydrocarbons, oxygenated volatile organic compounds, chlorine, bromine, fluorine, iodine, hydrogen chloride, hydrogen bromide, hydrogen fluoride, mixed halogen gases (such as ClF), and combinations thereof.

[0027] The flash Joule heating process can be selected from the group consisting of (a) synthesizing graphene by the flash Joule heating, (b) synthesizing carbides by flash Joule heating, (c) synthesizing flash ID materials, (d) flash-within-flash (FWF) Joule heating, (e) flash Joule heating of fiber reinforced plastic, and (f) high-energy flash Joule heating synthesis methods.Attorney Docket No.: 072174-06701

[0028] The thermally resistive reaction vessel can include a material having a characteristic selected from the group consisting of low thermal conductivity, low thermal expansion coefficient to reduce thermal shock, high melting point, opacity to visible and IR light, clay, brick, concrete, fire brick, ceramic, mullite, and combinations thereof.

[0029] The conductive medium can be a conductive carbon material having a conductivity of at least 10-3S / cm.

[0030] The conductive medium can be a non-conductive carbon having a conductivity of at most 10-3S / cm.

[0031] The conductive medium can include a conductive additive.

[0032] The conductive medium can include a catalyst. The conductive additive and the catalyst can be different.

[0033] The conductive medium can include a catalyst.

[0034] The catalyst can be selected from the group consisting of ferric chloride, ferrocene, nickel chloride, cobalt oxide, cobalt chloride, metalloid, transition metal, main group metal, organometallic, polyoxometalate, metal halide, metal oxide, metal sulfide, metal chalcogenide, and compounds thereof.

[0035] In general, in another embodiment, the invention features a method that includes adding a conductive medium in a reaction vessel. The reaction vessel is a conductive vessel operable as a first electrode. A second electrode is positioned in the conductive medium within the reaction vessel. The method further includes performing a flash Joule heating process. A voltage is applied across the first electrode and the second electrode to enable electric current to flow between the first electrode and the second electrode and through the conductive medium. The conductive medium is not under compression within the reaction vessel during the flash Joule process.

[0036] Implementations of the invention can include one or more of the following features asAttorney Docket No.: 072174-06701 described above.

[0037] In general, in another embodiment, the invention features a system that is operable to perform a method selected from the group of the above-described methods.BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG. 1 shows a schematic illustration of a large-scale Joule flash heating reactor (also referred to as a flash reactor).

[0039] FIG.2 shows a schematic of variations in mix methods, heating methods, and products of the scaled flash Joule heating reactor.

[0040] FIGS.3A-3D show the performance of the DEKOPRO arc welder. FIG.3A is a photo of the DEKOPRO DKUS-MMA-160A arc welder. FIG. 3B shows temperature plotted as a function of the welder current output setting of 200 mg of MCFG. FIG. 3C are images of 200 mg MC in an 8 mm inner diameter quartz tube with graphite electrodes being heated by the DEKOPRO welder plugged into a 120 V outlet, which was used for all figures here, at the specified current output settings listed below each image. FIG. 3D shows heating and cooling of a 200 mg MC sample using the DEKOPRO arc welder.

[0041] FIGS. 4A-4D show characterization of FG synthesized using the DEKOPRO arc welder. This FG was synthesized from a 200 mg batch of MC at a setting of 90 after a ~20 s flash. FIG. 4A shows average Raman map spectra (n = 200, 532 nm excitation) of 200 mg batches of MC after FJH for ~10 s at different current output settings. The standard deviation of each of these graphs is represented by the shaded area around the line, which is the mean.FIG. 4B shows high-resolution Raman spectroscopy, illustrating the two turbostratic peaks with the missing M-band, all indicative of turbostratic FG. The intensity ratio of the G peak to the TS1peak is ~160. FIG. 4C shows a TEM image of the FG product. FIG. 4D shows XRD pattern of the FG product.

[0042] FIGS. 5A-5F show additional FJH synthesis applications of the arc welder systems toAttorney Docket No.: 072174-06701 form CNTs, heteroatom-substituted graphene, and SiC. FIG. 5A shows the average Raman spectrum (n = 200, 532 nm excitation) of CNTs and FG synthesized from ferrocene and plastic waste. FIG. 5B shows the SEM image of CNTs from this same product. FIG. 5C shows high resolution Raman spectra of the RBMs of the innermost tubes of the multi -walled CNTs synthesized, using two different Raman excitation wavelengths. FIG.5D shows XPS spectrum of the products of the PFOS-MCFG FJH reaction. FIG. 5E shows Raman spectrum of SiC product resulting from FJH of 6 g mixture of GFRP-MC in a 2:1 mass ratio followed by combustion of the FG. The inset image is a photo of this FJH reaction. FIG. 5F shows X-ray diffraction pattern of the SiC product of this FJH reaction after a furnace heating step to combust the FG. The spectrum is illustrated above the corresponding powder diffraction file of 2H-SiC.

[0043] FIGS. 6A-6I show a kilogram-scale FJH reaction using a $180 Amico Electric arc welder on MC. FIG. 6A shows a schematic image of the clay pot filled with MC. A cross section has been cut out to show the contents. FIG. 6B shows a photo of the arc welder in use on -750 g MC in a clay pot, turning on a rotating platform at -3 rpm, reacting for 10 min at 3 kg / h FG production. FIG. 6C shows power and cumulative energy usage of a -70 s MC reaction plotted with respect to time. FIG. 6D shows the average Raman spectra (n = 200, 532 nm excitation) of the FG product synthesized using the Amico Electric arc welder and a TDK Lambda GEN 125-80 power supply. The standard deviation of each of these graphs is represented by the shaded area around the line, which is the mean. FIG. 6E shows a photo of the arc welder in use on a mixture of -900 g GFRP and MC, producing SiC at a rate of 430 g / h. FIG. 6F shows XRD pattern of SiC produced from the scaled synthesis method after FG removal by furnace treatment. FIG.6G shows an SEM image of CNTs on MC produced during a 550 g scaled reactor flash at $284 / tonne for the starting material and electrical costs of the flashing step. FIG. 6H shows FG production rate plotted as a function of system priceAttorney Docket No.: 072174-06701 comparing using a single Amico Electric arc welder (1 AW), 2 Amico Electric welders in series (2 SAW), and the TDK Lambda power supply (PS) with this scaled reactor compared to commercially available FJH systems from ACS Materials LLC, and a scaled FJH system previously reported. FIG. 61 show the FG production rate plotted as a function of system energy efficiency, comparing using a single Amico Electric arc welder (1 AW), 2 Amico Electric welders in series (2 SAW), and the TDK Lambda power supply (PS) with this scaled reactor compared to scaled FJH systems previously reported.

[0044] FIG. 7 is a side view photo of the large FJH clay reactor shown in FIG. 6B. Scale bar is 10 cm.

[0045] FIG. 8 shows a scaled FJH reactor procedure for utilizing the FJH reactor shown in FIGS. 6B and 7

[0046] FIG. 9 is a schematic illustration of a scaled SiC reactor.

[0047] FIG. 10 is a schematic illustration of a scaled CNT-MCFG reactor.

[0048] FIGS. 11A-11B show an illustration of resistance and electrode distance trends.

[0049] FIGS. 12A-12B show illustrations of different stirring configurations that can be used to improve product uniformity. FIG. 12A shows an illustration of a shaking platform used to shake the contents of the reactor. FIG. 12B shows an illustration of a stir rod used to stir the contents of the reactor.

[0050] FIGS. 13A-13E illustrations of different electrode configurations that can be used to improve product uniformity. FIGS. 13A-13B show side and top views, respectively of a reactor design by which one of the electrodes rotates around the sample to heat more uniformly. FIGS.13C-13D show side and top views, respectively of a 3-electrode design by which the 1 center electrode is of one polarity and the 2 satellite electrodes are of the opposite. FIG. 13E shows a side view of a 4-electrode design by which electrodes are grouped in pairs to operate at different depths and at different lateral positions.Attorney Docket No.: 072174-06701

[0051] FIG. 14 shows an illustration of constant flow system.

[0052] FIGS. 15A-15I show simultaneous flash-within-flash reactions performed using the Amico Electric arc welder. FIG. 15A shows an image of the 9 tubes filled with the inorganic reactant feedstock embedded in MC inside the clay flowerpot. FIG. 15B shows zoomed-in image of the tubes inside the flowerpot. The inset photo shows a single tube loaded with 0.4 g SnCl2·2H2O and 1.0 g S powder. FIG. 15C shows Raman spectra of SnS2and SnSe2. FIG.15D shows XPS spectrum illustrating Sn in the SnSe2product. FIG. 15E shows XPS spectrum illustrating Sn in SnS2product. FIG. 15F shows XPS spectrum illustrating Se in the SnSe2product. FIG. 15G shows XPS spectrum illustrating S in SnS2product. FIG. 15H shows XRD pattern of SnSe2. FIG. 15I shows XRD pattern of SnS2.DETAILED DESCRIPTION

[0053] The present invention relates to systems and methods utilizing a flash Joule heating reactor, and more particularly, systems and methods utilizing a large-scale flash Joule heating reactor of large masses of feedstock.

[0054] The systems and methods of embodiments of the present invention facilitate the scaled flash Joule heating of carbon feedstocks to produce graphene, CNTs, and, by combining with the flash within a flash method, enable the production of TMDs and PMDs. Multiple ways of mixing and heating the sample can be utilized to ensure sufficient and uniform heating over a large volume of sample, and the conditions can be varied and adjusted under which different products can be formed from the systems and methods. The synthesis can be achieved by adding an indiscriminate large amount of carbon conductive medium, such as metallurgical coke, into a large, thermally resistive reaction vessel, such as clay or thermal brick. Carbon waste, such as waste plastic, can also be added to the conductive medium to convert this to flash graphene. Conductive electrodes, often made of graphite, can be inserted into the conductive medium. A voltage is then applied across these two electrodes to enable electricAttorney Docket No.: 072174-06701 current to flow between them and through the sample. The flow of a high amount of current enables the flash Joule heating of the metallurgical coke. A simple illustration of this system is shown in FIG. 1 (with electrodes 101a-101b, clay reaction vessel 103, and conductive medium 102 (e.g., metallurgical coke)).

[0055] The highest temperature is achieved at the path between the two electrodes. Thus, moving the electrode position through the sample is desirable to achieve heating of the entire sample. The mixing techniques 201, heating methods 202, and products of this method 203 are summarized in FIG. 2. Any combination of one or multiple mixing and heating methods can be used at the same time, and any combination of one or multiple types of products can be obtained.

[0056] Parameters / declarations for the scaled flash Joule heating reactor include those summarized in FIG. 2 and include:

[0057] The reaction vessel can be preferentially made of a material with low thermal conductivity, a low thermal expansion coefficient to reduce thermal shock, high melting point, opacity to visible and IR light, clay, brick, concrete, fire brick, ceramic, and mullite. The reaction has been performed with a clay vessel, but it could also be demonstrated a clay flowerpot as used in this case, or thermal clay, thermal brick, clay, concrete, cement, brick or a graphite crucible, or brick where the graphite crucible is one of the electrodes.

[0058] The reactions have been demonstrated with graphite electrodes, but they could also be comprised of brass, tungsten carbide, silicon carbide, lanthanated tungsten, steel, iron, graphene, metals, metallic alloys, or other electrodes, especially metal composites or alloys, commonly used with arc welders.

[0059] The methods have been demonstrated with an unmodulated DC power source, a pulse-width modulated DC power source, an AC power source, an unmodulated DCAttorney Docket No.: 072174-06701 capacitor pulse, and a pulse-width modulated DC capacitor pulse, and arc welders, as well as multiple systems placed in series or in parallel.

[0060] When the desired product is graphene, then a carbon source, such as metallurgical coke, plastic, food waste, textiles, rubber, carbon black, tire-carbon-black, biochar, anthracite coal, activated charcoal / coal, or carbon-based oils can be used. Any of these feedstocks can be waste feedstocks. Graphene is preferentially formed when these feedstocks are brought to at least -2000 °C, as occurs with typical flash Joule heating. Lower temperatures of 1300 to 1500 °C are possible if reacted for longer periods of time, on the order of minutes rather than milliseconds to 60 seconds.

[0061] When the desired product is carbon nanotubes (CNTs), then a carbon source, such as metallurgical coke, waste plastic, carbon black, anthracite coal, activated charcoal / coal, or carbon-based oils, tire-carbon-black and biochar can be used along with a catalyst, such as ferrocene iron, nickel or cobalt salts or oxides, such as iron chloride or iron oxide. Heating the feedstock to -2000 °C will produce graphene with carbon nanotubes. Heating the feedstock to -500-1500 °C will produce mainly carbon nanotubes.

[0062] When carbon nanotubes are added along with the previous mixture, then carbon nanotubes can grow on these other carbon nanotubes, creating bottlebrush carbon nanotubes.

[0063] Other possible catalysts can include ferric chloride, nickel chloride, cobalt oxide, cobalt chloride, and other metal, metalloid, transition metal, organometallic, polyoxometalate, compounds, etc. The metal may be either a cation, or in a complex cation, or an anion, or a complex anion, or an oxide form.

[0064] Boron nitride nanotubes can also be grown by this method using boronAttorney Docket No.: 072174-06701 and nitrogen-containing precursors.

[0065] The interfaces of these 1D materials can be doped, modified, sized, or functionalized through flash Joule heating.

[0066] Carbon nanotubes can be grown onto non-volatile species of carbon, flash graphene, and metallurgical coke, by adding a catalyst, or by adding a volatile species of carbon, such as high-density polyethylene (HDPE) with the catalyst.

[0067] Carbon nanotubes can be grown on carbon fibers, chopped carbon fibers, silicon carbide particles, or other surfaces by adding metal catalysts such as iron, nickel, or cobalt, and using the fibers as the carbon source or adding an exogenous carbon source.

[0068] The methods can also be used to produce silicon carbide by using a mixture of a carbide feedstock and a silicon feedstock, including all the carbon feedstocks listed above as well as glass fiber reinforced plastics (GFRPs), silicon powders and wools, including waste silicon materials.

[0069] When the reactions are performed with a carbon feedstock at higher energies (power and duration) or temperatures, then ordered graphene and graphite can be formed in proportion to the energy used, and at the expense of turbostratic (disordered) graphene.

[0070] p-Block metal dichalcogenides (PMDs) and transition metal dichalcogenides (TMDs) can be formed by utilizing the flash-within-flash method in conjunction with this reaction vessel method. To achieve these products, the vessel can be filled with a conductive additive, such as metallurgical coke or metallurgical coke flash graphene. PMD or TMD reaction precursors are then placed inside small, thermally resilient vessels, such as fused silica tubes, and are capped at the at the ends, typically by smallAttorney Docket No.: 072174-06701 graphite cylinders. These tubes are inserted into the conductive feedstock inside the large vessel and arrayed evenly to ensure uniform heating. Upon heating, the precursors are reacted by the flash-within-flash method, forming the PMD or TMD product. This has been shown by using tin and selenium to make tin selenide (SnSe₂), tin and sulfur to make tin sulfide (SnS₂), and indium and selenium to make indium selenide (In₂Se₃). These tubes were placed in a nonagonal pattern around the center of the inner electrode in an array, to ensure uniform heating.• Heating was performed across approximately 1 minute.• As in conventional flash within a flash synthesis, other TMD and PMD products can be formed, including NiS2, FeS2, TiSe2, CU9S5, NbSe2, Cu0.87Se, CoSe, Bi2Se3, Bi2S3, WSe2, MoSe2, NiSe2, LaBO3, TiN, Bi2SxSey, CoSxSey, CoS2, WS2, SnSxSey, as well as any functionalized or doped variations of these compounds.• This modification on the flash within flash method can be used with other feedstocks as well, including other inorganic compounds, waste materials, including waste plastics, GFRPs, metallurgical coke, and carbon nanotubes.• Any combination of one or multiple products can be formed by simultaneous use of the relevant precursors.

[0071] Several mixing methods have been tested to ensure uniform heating and conversion of the chemical product. Any combination of one or multiple mixing methods can be used with any combination of one or multiple heating methods, to make any combination of one or multiple products. The mixing steps tested include the following:• Adding a shaker or vibrating platform to the reaction vessel to mix the contents.Attorney Docket No.: 072174-06701 • Using a turning platform at the base of the reaction vessel to turn it.• Extending a stir rod into the reaction vessel to mix the contents.• Moving the electrodes themselves throughout the reaction vessel to heat different parts and ensure uniform heating.

[0072] Several heating methods, related to electrode placement and use, have been tested to ensure uniform heating of the sample, and modify the heating rate and maximum temperature as desired. Any combination of one or multiple of these heating methods can be used with any combination of one or multiple mixing methods, to make any combination of one or multiple of the aforementioned products. The heating methods tested include the following:• Connecting multiple power supplies to the electrodes in series to modify the heating rate and maximum temperature.• Connecting multiple power supplies to the electrodes in parallel to modify the heating rate and maximum temperature.• Using multiple electrodes spread around the heating locations, ensuring more uniform heating and modifying the heating rate and maximum temperature.• Using a single electrode of one polarity in combination with multiple electrodes of another polarity, forming a main and satellite electrode scheme.

[0073] This scaled reaction chamber can be continuously fed in with any of the feedstocks and can continuously output products of the synthesis into another chamber or onto another platform, making this an automated and continuous synthesis process. This output scheme can be used with any combination of other procedures mentioned.

[0074] For example, the present systems and method can be utilized for the (a) synthesis ofAttorney Docket No.: 072174-06701graphene by flash Joule heating (such as described and taught in Tour ‘967 PCT Application), (b) synthesis of carbides by flash Joule heating (such as described and taught in Tour ‘030 PCT Application), (c) flash ID materials from plastic waste (such as described and taught in Tour PCT ‘000 Application), (d) flash-within-flash (FWF) Joule heating (such as described and taught in Tour ‘780 PCT Application), (e) flash Joule heating of glass fiber reinforced plastic (GFRP) to make SiC (such as described and taught in Tour ’588 PCT Application), and (f) high-energy flash Joule heating synthesis methods (such as described and taught in Tour ‘481 PCT Application).

[0075] The ability to use a large-scale flash reactor facilitates mass production of graphene, CNTs, PMDs, TMDs, and provides a large-scale upcycling route for metallurgical coke and waste plastics.

[0076] The present invention can produce (utilizing FJH) kilogram scales using commercial off-the-shelf systems available for as low as $120. These systems can be used as universal reactors to perform flash Joule and arc heating reactions to synthesize graphene, doped graphene, carbon nanotubes, carbyne, SiC, SnS2, and SnSe2. See TABLE I.TABLE IList of the major products synthesized, including the reaction system and parameters used Product Reaction Reaction Parameters Average Quality ProductScale (g)MCFG 0.2 DEKOPRO AW, 120 V I2D / G = 0.47, ID / G = 0.72 outlet, 90 a.u. output setting,20 sCNTs 0.2 DEKOPRO AW, 120 V I2D / G = 0.39, ID / G = 0.99 outlet, 70 a.u. output setting,10 sF-doped MCFG 0.2 DEKOPRO AW, 120 V 9 at% substitution outlet, 70 a.u. output setting,10 sMCFG 1 DEKOPRO AW, 208 V I2D / G = 0.49, ID / G = 0.72 outlet, 75 a.u. output setting,20 sMCFG 1 DEKOPRO AW, 208 V I2D / G = 0.40, ID / G = 0.74 outlet, 50 a.u. output setting,20 sAttorney Docket No.: 072174-06701SnS2 and SnSe2 1.6 Amico AW, 208 V outlet, 120 40% yield a.u. output setting, 30 sSiC + FG 6 Amico AW, 208 V outlet, 120 TO at 791 cm’1, LO at a.u. output setting, 30 s 968 cm’1; ITO / LO = 3.3 SiC + FG 110 2 Amico AW in series, 208 V TO at 778 cm’1, LO at outlet, 80 a.u. output setting, 963 cm’1, ITO / LO = 6.215.3 minMCFG 500 Amico AW, 208 V outlet, 200 I2D / G = 0.49, ID / G = 0.81 a.u. output setting, 10 minMCFG 500 TDK Lambda PS, 10 kW I2D / G = 0.52, ID / G = 0.77output setting, 6.7 min

[0077] These commercial systems exhibit superior temperature controllability relative to customized FJH systems and can be adjusted during a reaction. See TABLE II.TABLE IIComparison of capacitor-based, arc welder, and programmable power supply (PPS) FJH systems on the 8 mm tube synthesis of metallurgical coke-derived flash graphene (“MCFG”) Category Capacitor-Based FJH Arc Welder FJH PPS FJH energy efficiency ~10 kJ / g -20 kJ / g -20 kJ / g flash duration -0.1-5 s -5-30 s -5-30 s temperature control -100 °C, after -10 °C -1 °C optimizationlive temperature no yes yes controlsystem cost ~$1000-$20,000 ~$100-$200 ~$500-$7000 ease of use difficult facile facile graphene yield 90-99% 90-99% 90-99% graphene I2D / G 0.3-0.6 0.3-0.6 0.3-0.6 maximum -2500-3500 °C -2000-3000 °C -1500-3000 °C temperaturemaximum power -100-500 kW -5-10 kW -1-10 kWmaximum energy -1-70 kJ no maximum no maximum

[0078] The ranges listed in TABLE II reflect the variety of systems reported in the literature. Capacitor-based FJH systems are comparatively expensive, feature low temperature controllability, are difficult to use, and are limited by the finite energy stored in the capacitors. However, these systems also feature the highest power output and therefore are capable of achieving the fastest and most efficient FJH reactions that simultaneously achieve the highest temperatures. These systems are best-suited only for milligram-scale feedstocks and fast, nonequilibrium reactions requiring millisecond duration. [Chen 2021}. In contrast, arc welderAttorney Docket No.: 072174-06701 FJH systems offer superior temperature controllability for lower cost. Similarly, PPS FJH systems exhibit highly precise temperature controllability for still better cost and ease of use compared to capacitor-based systems. These two types of continuous flash Joule heating systems are also superior in their achievable scale, since there is no maximum energy output for these systems.

[0079] These methods of the present invention were achieve using multiple models of arc welders, a variable transformer, and a two programmable power supply models. Multiple arc welders connected in series can also permit larger-scale reactions. Input energy use and output voltage, current, and power signals with microsecond resolution were analyzed. Procedures are also provided to enabling modification of these systems, including making a portable battery-powered FJH system that is recharged with portable commercial solar panels. These inexpensive and commercially available electrical sources are effective FJH systems, particularly in the synthesis of graphene up to kilogram scales, all done in the open air. This protocol renders Joule heating chemistry at the kilogram scale readily accessible.Synthesis of Flash Graphene with an Arc Welder

[0080] FJH reactions are commonly performed inside a tube reactor where the target feedstock is placed inside a fused quartz tube and between two graphite electrodes, which themselves are connected to the FJH system. Metallurgical coke (MC) is a commonly used feedstock in these reactors. [Luong 2020,' Eddy 2023 for flash graphene (FG) synthesis due to its high carbon content, low monetary cost, and resistivity of -0.01 m [Surup 2020], which translates to a resistance of -1 when packed into a FJH tube, commonly in 200 mg batches.

[0081] During the FJH reaction of a carbon feedstock, all the bonds within the carbon-based reactants are likely broken, and the reactants reform into graphene that is turbostratic in alignment, meaning that the layer stacking is disordered and thus exhibits a higher interlayer spacing relative to ordered graphene. [Luong 2020], This mechanism has been studied andAttorney Docket No.: 072174-06701 theoretically modeled in detail in prior studies by Applicant. [Deng 2021}. The previous use of this MC feedstock inspired the synthesis of metallurgical coke-derived flash graphene (MCFG) with an arc welder, as illustrated in FIGS. 3A-3C.

[0082] A $120 DEKOPRO DKUS-MMA-160A arc welder (Amazon, FIG. 3A) was used to heat 200 mg batches of MC using different arc welder settings. Electrical, thermal, and optical hazard safety procedures were followed during all reactions. The temperature of the reaction was measured using a Micro-Epsilon CTRM1H1SF100-C3 pyrometer at 1 ms resolution, with a minimum temperature threshold of 1000 °C. The system current setting, which increases the electrical current output but does not correspond to the output in a 1:1 ratio, was adjusted in increments of 5 on the arc welder screen, resulting in an average temperature change of 35 °C per the 5-increment adjustments. FIG. 3B. The arc welder was plugged into a 120 V outlet. MCFG was used for this measurement to avoid any heat contribution from the thermochemical transition from MC to MCFG. The current setting offers tunability at this scale of as little as 7 °C / setting increment. Dots 301 shown in FIG 3B illustrate the settings used in the experiment, and the dotted line 302 illustrates the linear fit of the sample temperature plotted as a function of these settings. Each temperature increment was achieved after ~10 s of heating, relative to the previous increment.

[0083] This corresponds to temperature tunability on this system of 7 °C / increment for this sample, which is very good control at these high temperatures. A sample of greater heat capacity would have correspondingly higher temperature tunability. Temperature control of this precision can be maintained during reactions even minutes in duration, although temperature-dependent sample resistance changes may require slight setting adjustments to maintain a constant temperature. This arc welder source is only slightly larger than a shoebox and weighs only 5.5 kg, underscoring the simplicity of arc welders as power sources. FIG.3C shows the changes in sample luminosity as a function of arc welder heating. These currentAttorney Docket No.: 072174-06701 settings were read from the screen of the arc welder and correspond to the output current, but the setting displayed on the arc welder is not the current output in amperes, and hence these units are labeled as arbitrary units (a.u.). Additional images are shown in FIG. 3D.

[0084] In FIG. 3D, each photo was taken 5 s after the previous, during which time the arc welder was incremented by a current setting of 5 a.u., as read from the arc welder screen. Scale bar, 2 cm. Each increment results in a temperature change of ~35 °C on the outer surface of the feedstock per 5 a.u. change of current setting (FIG. 3B). Previous millisecond-scale FG reactions achieved FG conversion at 2500-3000 °C in a 4 mm diameter reaction tube [Chen 202L, Luong 2020,' Stanford 202], and -5 s-scale reactions demonstrated FG formation at as low as -1600 °C in a 16 mm diameter reaction tube [Eddy 2023],Characterization of Arc Welder FG

[0085] Consistent with conventional FJH reactors, the quality of the FG produced corresponds to the input energy and power. This quality is evaluated in terms of turbostraticity, interlayer spacing, crystallinity, and defect density. Raman spectroscopy is one of the primary tools for bulk analysis of graphene. The Raman spectrum of FG exhibits a D peak at -1360 cm’1, which arises from defects in the graphene lattice or non-zigzag edges, a G peak at -1600 cm’1, which comes from the breathing modes of sp2carbon bonds [Beckham 2022], and a 2D peak at -2700 cm’1, which has an intensity proportional to the crystallinity of graphitic layers and inversely proportional to the coupling between layers. [Luong 2020,' Beckham 2022,' Canqado 2011],

[0086] The intensities of the D and 2D peaks are often normalized by the intensity of the G peak, leading the peak intensity ratios, denoted ID / Gand I2D / G, to be considered quantitative values, where a lower ID / Gindicates less defective graphene, and a higher I2D / Gindicates better graphene conversion. [Luong 2020]. Conventionally, an I2D / Gof at least 0.3 indicates graphene conversion. [Beckham 2022],Attorney Docket No.: 072174-06701

[0087] FIG. 4A illustrates the effects of different current settings on the FG product (plots 401-403 for current settings of 10, 50, and 90 a.u., respectively), using the DEKOPRO arc welder. B The graphene yield can be monitored by investigating the emergence of the 2D peak. No FG is observed after reacting with a setting of 10, low FG yield with a setting of 50, and higher FG yield with a setting of 90, out of a maximum setting of 160. The long duration of the reactions in comparison to those with capacitor-based FJH systems enables FG synthesis to occur well under 3000 °C.

[0088] The turbostratic character of graphene was investigated by using a high-duration Raman scan to examine two small turbostratic (TS) peaks at -1880 cm’1and -2040 cm’1, which are present in turbostratic graphene and absent in ordered graphene. These peaks are also present in FG produced with the arc welder (FIG. 4B) at a setting of 90, even though the reaction duration is -20 s, compared to conventional FJH reactions below 5 s. An ordered graphene peak, denoted the M peak, which normally occurs at -1740 cm’1, is also absent.

[0089] A transmission electron microscopy (TEM) image of this same FG product (FIG. 4C) illustrates graphitic ordering, though with an interlayer spacing of 3.47 A, which is characteristic of turbostratic graphene [Luong 2020} and is higher than the AB-ordered graphene interlayer spacing of -3.35 A. (A low-resolution TEM characterization revealed the sheet size to be ~3 μm2).

[0090] The X-ray diffraction (XRD) pattern of the product (FIG. 4D) illustrates the high crystallinity of the sample by the narrow (002) peak, and the 3.42 A interlayer spacing as determined by the position of the (002) peak is well within the 3.4-3.5 A range seen in metallurgical coke (MC) derived FG. [Eddy 2023}.

[0091] Combining the information from FIG. 3B and FIGS. 4A-4D, it was concluded that metallurgical coke-derived flash graphene (“MCFG”) can be formed from a metallurgical coke (“MC”) feedstock with a reaction surface temperature as low as -1500 °C (but certainly higherAttorney Docket No.: 072174-06701 than -1200 °C), when the sample is heated for -20 s. Thus, the use of a continuous and controllable Joule heating system, such as with an arc welder, can enable future studies on the flash graphene transition phase space.

[0092] FIG. 3B and FIGS. 4A-4D together demonstrate that MCFG with a I2D / Gratio of 0.72 can be synthesized using FJH reaction temperatures of as low as -15000C at -20 s reaction duration in an 8-mm-diameter reaction tube. When the arc welder FJH reaction on MC is performed at -12000C, an increase in the product I2D / Gto 0.29 is observed, which is greater than the value for raw MC (I2D / G~0.1)5[Eddy 2023 or even that for MC heated at the minimum arc welder setting (I2D / G= 0.11); however, this increase is not sufficient for the product to be considered FG [Beckham 2022], This agrees with previous studies on the FG reaction transition suggesting that both FJH reaction temperature and duration are parameters that determine the FG formation, while no FG transition is observed below a certain temperature threshold. [Eddy 2024], Thus, it can be concluded that FG is first observed during FJH at -1500 °C, and additional heating at higher temperature or longer duration merely increases the portion of the MC converted to FG. Utilizing these continuous and controllable FJH systems can illustrate more completely the FG conversion reaction temperature vs. time results.Other Arc Welder Reactions

[0093] FJH is also an effective tool for the synthesis of carbon nanotubes (CNTs) from amorphous carbon as well as from waste plastics, including high-and low-density polyethylene, polypropylene, polystyrene, and poly(ethylene terephthalate). [Wyss 2023], This can be best achieved through a wet mixing method by which plastic waste is dipped into a water-ethanol solution into which has been dissolved 0.1 wt% ferrocene. This waste plastic product is electrically resistive, so it can be mixed with a conductive additive before it is placed in the quartz tube, such as carbon black or MC, to reduce its resistivity and enable FJH. CNTs begin to form by FJH at as low as -800 °C, well beyond the glass-transition temperature of mostAttorney Docket No.: 072174-06701 commodity polymers (-100 to 100 °C) and can coexist with FG in reactions that occur at -2000 °C. Temperatures higher than this form a greater portion of FG with lower portions of the CNT product. [Wyss 2023],

[0094] Conveniently, the outgassing typical of flash Joule heating expels most surface contaminants and non-carbon atoms [Luong 2020], allowing even mixed and low-purity waste plastics to be flash Joule heated. Accordingly, waste plastic (high-density polyethylene, HDPE) with ferrocene, mixed with 20 wt% carbon black as the conductive additive, was flashed using the same DEKOPRO commercial arc welder, at a 200 mg sample size of this mixture, in a fused quartz tube. The arc welder was turned to a setting of 70 and the mixture was heated for 10 s to produce a mixture of CNTs and FG.

[0095] FIG. 5A illustrates the Raman spectra of the product, which consists of successfully converted FG as well as CNTs, as evidenced by the radial breathing mode (RBM) Raman peaks at -220 cm’1and -285 cm’1. The presence of these RBMs confirm the synthesis of CNTs in the product. [Advincula 2021; Sattari 2023], Since these are multi -walled carbon nanotubes, detailed diagnostic information of indices, diameter, and configuration cannot be easily established. [Beckham 2022,' Surup 2020,' Basirjafari 2013,' Maultzsch 2005],

[0096] Scanning electron microscopy characterization of this same product (SEM, FIG. 5B) shows the CNTs, which exhibit a diameter of -100 nm, typical of multi-walled CNTs formed from this method. [Wyss 2023], This reaction was performed at a comparatively low arc welder setting and thus exhibited some regions of amorphous carbon in addition to FG, demonstrating that CNTs can be made with or without FG. The ratio of FG-to-CNTs produced is proportional to the reaction temperature and is thus controllable by the arc welder setting. [Wyss 2023],

[0097] Raman spectroscopy analyses of the RBMs of the CNTs using two different Raman excitation wavelengths were performed (FIG. 5C with plots 521-522 for 633 nm and 532 nm,Attorney Docket No.: 072174-06701 respectively). Additional SEM and energy dispersive X-ray analysis showed that only trace amounts of iron from the ferrocene are present in the same product.

[0098] A simplified mixing technique can also be used with the arc welder, whereby the ferrocene is mixed directly into the plastic-carbon black mixture, without any wetting or drying steps. This method also produced CNTs, though with a lower yield than with the wet mixing method. Additionally, nitrogen-rich polymers, such as polyaniline, can be used as a feedstock to synthesize nitrogen-doped CNTs. [Zhang 2024}.

[0099] The versatility of FJH reactions also enables the synthesis of heteroatom-doped FG.[Wang 2014}. To achieve this, heteroatom-containing compounds were mixed in with the amorphous carbon reactant. The resulting mixture was then FJH to produce heteroatom-doped FG. A variant of this technique involves flashing the heteroatom compound in the presence of FG to achieve a still higher doping concentration, termed heteroatom-substituted reflash graphene. Based upon these and by the previous work on destroying harmful per- and polyfluoroalkyl substances (PF AS) [Scotland 2024: Cheng II 2024: Scotland I 2025; Scotland II 2025], heteroatom-substituted reflash graphene was synthesized using the DEKOPRO arc welder to perform an FJH reaction on a 200 mg mixture of perfluorooctane sulfonic acid (PFOS) and MCFG mixed in a 1:4 weight ratio. The resulting product achieved ~9% fluorine substitution, as demonstrated by X-ray photoelectron spectroscopy analysis. FIG. 5D (showing fluorine substitution into the FG lattice is achieved at ~9 at%).

[0100] Tube FJH reactions with this DEKOPRO arc welder can be performed in even gramscale batch sizes, still affording successful graphene conversion. This near-constant heating rate also illustrates the thermodynamics of the graphene reaction, since the first temperature maximum at ~5 s arising from the graphene and MC volatiles exotherm is visible. [Eddy 2024}.

[0101] FJH has also been effectively used in the upcycling of glass fiber-reinforced plastics (GFRP) to efficiently produce SiC. [Cheng 12024}. Using a higher-power arc welder, such asAttorney Docket No.: 072174-06701 an Amico Electric ARC-200DC, enables upcycling of GFRP into SiC within the quartz tube even up to a 6 g scale reaction. FIG. 5E (with inset image 541 showing a photo of this FJH reaction); FIG. 5F. GFRP decomposes at -1000 °C, but the best SiC quality is achieved at -2000 °C, which can be reached at this scale by a DEKOPRO arc welder, plugged into a 208 V outlet, at maximum setting (160 a.u.).

[0102] As with conventional flash Joule heating, the thermal expansion of air and the release of volatiles from the feedstock during the flash reaction result in an outgassing of the sample, forcing oxygen out and thus inhibiting some of the oxidation of the flash graphene product. This reduces the oxidation of the flash graphene product to a thin layer on the surface. The presence of a more oxygen content in the reaction feedstock can, however, result in an oxygen-doped FG product. Previous studies on the presence of oxygen upon the surface of the FG product has found this limited to -2 at%. This can also be further reduced by FJH in an inert environment.Other Commercial Systems

[0103] The DEKOPRO arc welder offers vastly superior price, temperature controllability, and ease of use compared to conventional FJH electrical systems. However, other heating systems can offer higher power output and still higher temperature controllability than even the DEKOPRO system, all while remaining more economical and facile than conventional FJH systems. Several alternative systems for FJH were examined and tested, with prices ranging from $125 to $6500. TABLE IIIAttorney Docket No.: 072174-06701TABLE IIICommercial flash Joule heater detailsType Model Max Price Rated (USD) Output(kW)Arc Welder DEKO DKUS-MMA-160A 5.8 120 Arc Welder Amico Electric ARC- 7.8 180200DCProgrammable Power Supply Zhaoxin KXN-3060D 1.8 500 Variable Transformer Powerstat 2PF136B 3.1 1700 Programmable Power Supply TDK Lambda GENESYS 10 5000 GEN 125-80-3P208Arc Melter Lincoln Electric Precision 10 6500 TIG 275

[0104] These systems each exhibit different voltage, current, and thus power ranges, which also depends by Ohm’s Law on the sample resistance. To explore the effects of these systems on FG conversion, FG was synthesized electronic waste was recycled [Deng 2021} using both an alternating current (AC) Powerstat variable transformer and a direct current (DC) Zhaoxin programmable power supply. In doing so, FJH reactions were successfully demonstrated using both AC and DC power sources.

[0105] While the monetary cost per kilowatt output of programmable power supplies is in general higher than that of arc welders, they offer higher controllability, typically in increments of 0.1 A and 0.1 V. In contrast, arc welders do not typically feature as precise voltage controllability and exhibit current controllability of ~1 A. The high controllability of the programmable power supply facilitates thermodynamic analysis of FJH reactions.

[0106] Furthermore, programmable power supplies could also be used in a feedback mode with a temperature monitor to provide additional sample temperature stability. Analysis revealed that the FJH conversion of MC into MCFG was at constant power, except for a brief spike at the beginning. Such results show that even with constant power output, the conversion of MCAttorney Docket No.: 072174-06701to MCFG experiences two temperature maxima: one from the Joule heating, and one from the 34 kJ mol-1exotherm of the reaction. [Eddy 2024],

[0107] It has previously been reported by Applicant that the use of an oscillating current, such as a pulse-width modulated DC current, during FJH affords superior FG conversion compared to FG formed from a non-oscillating current. [Eddy 2023,' Eddy 2024}. Performing a fast Fourier transform on the output current signals of the arc welders reveals that the arc welders’ output with a duty cycle of multiple different frequencies, including one at ~9.6 kHz. This provides the arc welders with an innate advantage in the FJH synthesis of FG and other 2D materials, compared to conventional flash Joule heaters.

[0108] Additionally, arc welders can be arranged in series or parallel to increase power output. The power source of the arc welder can also be tuned. Rather than connecting to a stationary power outlet, a simple system can be constructed whereby an arc welder can be powered by a portable power system. Such system was assembled, using a car battery, which was charged from solar panels, to enable a portable flash Joule heater that operates entirely on solar power, which can be assembled for only $422. TABLE IV.TABLE IVList of parts used for the solar powered portable FJH systemType Model Price (USD) Solar Panel (x2) Marxon XP100 178 Car Battery EverStart Value Lead Acid Automotive Battery, 70Group Size 24F 12 Volt, 585 CCAInverter JUPITER 2000 Watt Continuous / 4000 Watt Peak 150Modified Sine Wave Power InverterInductor 0.5 mH Inductor 10 Arc Welder DEKO DKUS-MMA-160A 120Total 422 Arc Heating

[0109] Arc welders are specifically designed to facilitate arc heating by automatically raising the DC voltage in its open circuit state until an arc is formed, at which point the voltage decreases. This same technique has been recently repeated with a TDK Lambda GENESYSAttorney Docket No.: 072174-06701 power supply in order to perform ultrahigh temperature plasma synthesis by creating an arc across layers of carbon felt. [Xie 2023], This technique is also possible using arc welders, which are typically 1 / 30 the cost of programmable power supplies of comparable power output, even across carbon paper.

[0110] Arc melters have been a widely used tool in inorganic synthesis for decades as ultrafast reactors and are thus commonly present in solid-state synthesis laboratories. They are comprised of an arc welder, which provides the heating, connected to an evacuated chamber wherein a user-controlled needle electrode operates as one electrode, and a copper or brass mortar onto which the reactants are placed operates as the other electrode. Motivated by this, we also tested a Lincoln Electric Precision TIG 275 arc welder connected to an arc melter chamber, using a copper mortar and a 2% lanthanated tungsten electrode, to use arc heating to convert MC into MCFG.

[0111] The metal presence in the electrodes provided sufficient catalyst to form carbyne chains, rapidly identified by a prominent C band, measured by Raman spectroscopy in different samples from ~1770 cm-1to ~1840 cm-1using multiple excitation wavelengths (532 nm, 633 nm, and 785 nm). These distinct Raman diagnostic signals are definitive fingerprints of their presence. These carbyne chains are likely bound inside and stabilized by multi -walled CNTs on the surface of the MCFG. [Zhao 2003 Andrade 2015], This technique had previously only been achieved using higher value, 99.99% graphite rods, and had not previously been reported on a separate feedstock. [Zhao 2003,' Andrade 2015],Kilogram Scale FG Production

[0112] Previous attempts at scaling up FJH reactions have been made by rapidly automating small, gram-scale batches of feedstock to achieve cumulative large-scale synthesis over time, even up to kilogram-scale in hours. These FJH systems tend to involve elaborate automation assemblies. [Eddy 2023], Arc welders provide a facile alternative to scaled and customizedAttorney Docket No.: 072174-06701 FJH system, can be operated rapidly, require minimal training, and are less than 1% of the cost of dedicated FJH systems.

[0113] A kilogram-scale FG reaction using an Amico Electric ARC-200DC arc welder is shown in FIGS 6A-6B and FIG. 7. The reactor consists of this arc welder connected to two graphite rods (graphite electrodes 601), placed inside a 13 L, $9.97 clay flowerpot (Home Depot) (clay pot 603) that is filled with 500 g MC (MC 602) and open to the air. FIGS. 6A; FIG. 7

[0114] As shown in FIG. 7, the graphite electrodes are held by metal clamps connected to the Amico Electric arc welder. Thus, a continuous electrical connection exists between the arc welder and the graphite electrodes, with the MC in the clay pot closing the circuit. These metal clamps are in turn held in place by rubber clamps, suspended by a metal stand. The clay pot itself is sitting on a JAYEGT rotating platform that can be operated by remote control. A thin wooden slab rests between the clay pot and the rotating platform to provide thermal protection for the platform. The rotating platform has a 22 cm diameter and a weight limit of 80 kg.

[0115] Unlike large Pyrex beakers that cracked under these thermal stresses, the flowerpots remained uncracked. The arc welder cathode (negative) clamp was attached to the end of a 0.2 m long, 16 mm diameter graphite rod ($15.99, Amazon), and the anode (positive) clamp was attached to the end of a 0.2 m long, 8 mm diameter graphite rod ($4.80, Amazon). The pot is placed atop a $52.99 JAYEGT Motorized Rotating Display Stand rotating platform system (22 cm, 250 lb load rating, wired, Amazon) (wood block 604).

[0116] When the arc welder is turned on, an electric current is permitted to flow across the two graphite electrodes, and rotation of the platform at ~3 rpm automatically stirs the reactor and ensures uniform heating. FIGS.6A-6B. The FJH electrodes are also moved during the reaction to heat a different radius of sample. For instance, the heating radius can be adjusted simply byAttorney Docket No.: 072174-06701 moving the stand holding one of the clamps to ensure uniform heating. These metal clamps can also be manipulated by hand in order to stir the mixture and ensure uniform heating.

[0117] FIG. 8 shows scaled FJH reactor procedure utilizing the reactor shown in FIGS. 6A-6B and FIG. 7 in which product conversion and uniformity has been achieved, for the reactor filled with -750 g of feedstock. In step 801, an optional pretreatment step may be implemented for samples with higher resistance or heat capacity. Step 801 is not necessary for synthesis of MCFG, but it is generally necessary for SiC synthesis from GFRP waste. Step 801 heats up the center of the sample, without yet using the rotating platform, making it more electrically conductive to facilitate the heating of a wider volume. The electrodes can start at a distance sufficiently close for heating to begin. As the sample heats and decreases in resistance, then the electrodes can be spread apart to increase the heating volume.

[0118] In step 802,the rotating platform is turned on, and the electrodes are moved to a position where they can heat most of the center volume of the top of the sample.

[0119] In step 803, one or both electrodes are moved to a position at the edge of the sample where the outer volume can be more effectively heated.

[0120] In step 804, one or both of electrodes are moved back to the center and dipped lower into the sample to heat at a greater depth.

[0121] In step 805, the middle 2 / 3 of the sample (~ 500 g) is recovered as MCFG product. The MC nearest to the bottom and edges of the reactor have the lowest conversion rate and are instead reused between flashes, and thus this MC was not counted toward the reactor production rate. This relatively unconverted MC provides thermal protection to the clay reactor vessel, allowing the vessel to be reused indefinitely. The graphite rods slowly degrade and should be replaced after every - 5 kg MCFG produced. Low-purity graphite can be preferred due to its low cost.Attorney Docket No.: 072174-06701

[0122] This reactor is innately more energy efficient than other flash Joule heating schemes. Each volume that is heated warms the area around it, expediting its heating when the electrodes are moved. When a carbon feedstock is used, this also pyrolyzes the feedstock, increasing its conductivity. In addition to this, many species of carbon, including MC, have a negative resistivity-temperature coefficient by which the feedstock becomes more conductive at higher temperatures. These effects mean that the heat that dissipates from the inner radius of the feedstock is absorbed into the outer radius of the feedstock, reducing the energy required to later heat it. This is contrasted to conventional FJH tube reactors in which the heat is more quickly lost to the environment, since the reactor surface area-to-volume ratio of conventional tube reactors is far higher than that of the scaled clay reactor. Furthermore, the scaled clay reactor is made of a material that is opaque in both the visible and IR spectra, meaning that radiative heat loss is mostly blocked. Conventional FJH tube reactors used fused silica, which is mostly transparent in both the IR and visible spectra, thus barely mitigating radiative heat loss.

[0123] The long duration of this reaction permits the exertion of enough energy to convert the entire 500 g of MC to MCFG. FIG. 6C (with plots 621-622 for, respectively, power and cumulative energy); FIG. 6D (with plots 631-632 for power supply and arc welder). The temperature of the reaction reaches over 3000 °C (Micro-Epsilon CTRM1H1SF100-C3 pyrometer), while the average sample resistance decreases during conversion. Batches can be easily loaded and unloaded into the reaction vessel, and thus two consecutive reactions were performed to achieve 1 kg MCFG in total product after 20 min of heating.

[0124] This technique was also used to FJH a 900 g batch of waste GFRP and MC, mixed in a 1:2 weight ratio, to produce SiC. FIG. 6E; FIG. 6F (with plots 651-652 for 2H-SiC and 3C-SiC, which phases were both produced); FIG. 9. As shown in the schematic of FIG 9, the reactor was used to synthesize SiC by first packing 500 g large grain MC 902a (1.7-3 mm) intoAttorney Docket No.: 072174-06701the clay pot, covering this MC with a Garolite G-10 GFRP cylinder 906 (2 mm thick), then covering this cylinder with an additional layer of 300 g MC 902b, and finally pouring in a 900 g of 1:2 GFRP-MC mixture 905. The fine powder GFRP-mixture was more densely packed than the large grain MC mixture and thus occupied only the top-most volume of the clay pot reactor.

[0125] This technique was also used to FJH a mixture of 50 g HDPE loaded with 1 wt% ferrocene. This higher ferrocene loading was used in the flowerpot reactor since it was added as a solid. The 50 g HDPE was also mixed with 500 g MC (MC-HDPE 1005) to grow CNTs on the MC. See FIG. 10.

[0126] FJH reactions become more efficient at large scales, since most of the heat is transferred into the reaction instead of out to the environment. [Eddy 2024], This production method features a higher production rate than other scaled and automated FJH production methods reported in the literature by a factor of up to 220 [Zhu 2024} and is also more energy efficient, producing graphene with -60% less energy per product mass [Eddy 2023; Zhu 2024; Wyss 2022]. FIG. 6E. This improvement in efficiency results in a proportional reduction in greenhouse gas emissions, relative to these other methods. TABLE V.TABLE VComparative CO₂ emissions of different kilogram-scale FG synthesis methods from the electricity used during flash Joule heatingGreenhouse Gas Emissions from Electricity per kg Flash Graphene Method Energy Efficiency CO₂ Equivalent (MJ / kg) Emissions (kg / kg) Scaled Flash Reactor (2 SAW) 6 0.6 Small Methods FG Production [Eddy 2023} 7.5 0.81 Nature Communication FG Production 13.7 1.48[Zhu 2024}

[0127] CO2 emissions are calculated from the U. S. 2022 average of 0.39 kg CO2 equivalent per kWh (0.108 kg / MJ). [US EIA I 2024]. The efficiency of the scaled reactor system presented here translates to a proportional reduction in CO2 equivalent emissions relative to those of other methods.

[0128] Simultaneously, this reaction system can be constructed at ~l / 160ththe cost of even milligram-scale commercially sold FJH systems. [Col-Int Tech 2024}. Production rate can beAttorney Docket No.: 072174-06701 further increased by using multiple arc welders simultaneously, in series to increase maximum output voltage or parallel to increase maximum output current, which is up to 30 times more cost-effective than purchasing larger power supplies.

[0129] Flashing with arc welders in series or using a power supply that outputs higher voltage is also an effective way to heat a larger volume at a time. FIGS. 11A-11B. In FIG. 11 A, in an MC sample, an inter-electrode distance across the sample of 3 cm will exhibit an electrical resistance of ~1.5 while the sample is cold. This resistance will then halve when the sample is hot and carbonized. For such a sample, a FJH system should be used for which the maximum current to voltage ratio (V / I) is close to 0.7, such as the Amico Electric arc welder. This is also known as impedance matching. Deviating far from this ratio will prevent the system from outputting near its maximum power. In FIG. 11B, in an MC sample, an inter-electrode distance across the sample of 6 cm will exhibit an electrical resistance of -3 Q while the sample is cold. This resistance will then halve when the sample is hot and carbonized. For such a sample, a FJH system should be used for which the maximum current to voltage ratio (V / I) is close to 1.5, such as two Amico Electric arc welders connected in series, or a TDK-Lambda GEN 125-80. In this way, systems with higher V / I ratios are more suitable to heating larger volumes of samples at a time.

[0130] Product uniformity could also be improved using additional stirring (FIGS. 12A-12B) and electrode configurations (FIGS. 13A-13E).Mixing Methods

[0131] Mixing the feedstock with the scaled reactor can be utilized, and has import, to improve the uniformity of the heating. Several different mixing methods may be used on their own, or in conjunction with other mixing methods, to achieve this. Any number of mixing methods may then be used to form any combination of products previously mentioned.Attorney Docket No.: 072174-06701

[0132] In lieu of the rotating platform 604 shown in FIG. 6A, FIG. 12A utilizes a shaking platform 1201 used to shake the contents of the reactor and FIG. 12B utilizes a stir rod 1211 used to stir the contents of the reactor. The vibrating shaker 1201 of FIG 12A can be placed below the reaction vessel in order to shake the contents, moving them around the electrodes and thus distributing the heating of the sample. A simple stir rod 1211 can be placed into the reactor feedstock in order to stir the feedstock around the electrodes to improve the uniformity of heating. The stir rod can itself be thermally resilient. Stir rod 1211 itself could also be a flashing electrode.Mobile Electrodes

[0133] FIGS. 13A-13B show side and top views, respectively of a reactor design by which one of the electrodes rotates around the sample to heat more uniformly. One or multiple of the electrodes themselves can move with respect to the feedstock and the reactor in a stirring motion. This stirring may be performed either by a device or by a human user.Main and Satellite Electrodes

[0134] FIGS. 13C-13D show side and top views, respectively of a 3 -electrode design by which the 1 center electrode is of one polarity and the 2 satellite electrodes are of the opposite. More than 2 satellite electrodes could also be used. As a variation of multi-electrode heating, a single electrode of one polarity may be placed in the center of the vessel, while multiple other electrodes of opposite polarity may be placed, evenly spaced, around it. This is another arrangement by which more uniform heating can be achieved by electrode placement. Generally, the polarity of the main electrode does not matter, so long as it is the opposite of the satellite electrodes. Evenly spacing the satellite electrodes with respect to each other and with respect to the main, center electrode facilitates uniform heating.Attorney Docket No.: 072174-06701 Multiple Heating Electrodes

[0135] FIG. 13E shows a side view of a 4-electrode design by which electrodes are grouped in pairs to operate at different depths and at different lateral positions. Heating at multiple separate places in the sample can further assist in uniform heating, relative to using only two electrodes. These pairs of electrodes can be placed at different spacings, lateral positions, and depths throughout the reactor to facilitate this. Each electrode pair can be powered by its own power supply, or they can share a single one. Heating performance works best when the distance between the positive electrode of one electrode pair is kept further away from the negative electrode of a separate electrode pair.Continuous Production

[0136] Adding a simple automated loading and unloading process could enable continuous production of FG from carbon or waste materials (FIG. 14) while simultaneously ensuring that the highest quality product exposed to the highest reaction temperatures at the center of the reactor is separated from the lower quality product exposed to lower reaction temperatures at the edges of the reactor. As shown in FIG. 14, feedstock 1401 is continuously filled into the upper reactor where flashing occurs. A conductive additive such as MC or MCFG 1402 can be mixed with carbon waste sources 1403, such as plastic waste. The arc welder FJH reaction occurs near the bottom of the vessel (level 1406), which simultaneously pretreats through carbonization the feedstock above it (level 1405) while warming the region above this (level 1404), reducing the energy required for FJH. The graphene product 1408 is then output through a hole 1407 below the system. The graphene product 1408 can be reused as the conductive additive. Another benefit of this system is that the feedstock 1401 that is able to pass through the hole 1407 at the bottom of the reactor must pass in close contact with the FJH electrodes. This means that only the feedstock 1401 exposed to the highest reaction temperatures and thus converted to the highest quality FG 1408 passes into the lower chamber as reaction product. InAttorney Docket No.: 072174-06701this way, the highest quality FG 1408 product is automatically separated from lower quality FG product at the edges of the reaction chamber. This improvement in product quality separation should be paired with improved methods for product quality characterization before this system is further scaled-up.

[0137] One method for product characterization includes first removing the selected product (consisting of the innermost 2 / 3 of the reactor contents in the case of MCFG synthesis), then mixing the selected product together, and finally removing -300 mg of this for Raman characterization of this product across 100 separate points. Further techniques can involve sampling across a wider portion of the FG product to ensure product uniformity even to tonne scales.

[0138] A pipe-like configuration for continuous-feed rather than batch-feed is a worthwhile industrial extension. Pairing this technique with an improved characterization protocol to verify product uniformity further enables scaling-up of this technique to a continuous-feed pipe-based system with topological features to ensure mixing as the feedstock passes through the reactor. Finally, flashing MC in this scaled reactor at higher energy per mass will convert the initial turbostratic (disordered) MCFG into ordered FG and graphite. [Eddy 2024}.

[0139] FIG. 6G shows SEM image of CNTs on MC produced during a 550 g scaled reactor flash at $284 / tonne (TABLE VI) for the starting material and electrical costs of the flashing step.TABLE VICost Breakdown of 1 tonne Carbon Nanotube-Flash Graphene ($283,54) Input Type Cost (USD) Reference 1 tonne metallurgical coke 90 [Alibaba 12024}100 kg post-consumer HDPE 52.78 [Plastics Recycling Update 2024} 0.5 kg ferrocene powder 3 [Alibaba II 2024} 8000 MJ (2222 kWh) electricity 137.76 [US EIA II 2024}Cost analysis was performed assuming a 91 wt% total of carbon content among the 1.1005 tonne of reactants. The electricity price was obtained from the average industrial price of electricity in Texas, where this work was performed, during June 2024. This value is $0.062 / kWh. [US EIA II 2024}.Attorney Docket No.: 072174-06701

[0140] FIG. 6H shows FG production rate plotted as a function of system price comparing using a single Amico Electric arc welder (1 AW) 674, 2 Amico Electric welders in series (2 SAW) 675, and the TDK Lambda power supply (PS) 676 with this scaled reactor compared to commercially available FJH systems 671-672 from ACS Materials LLC, and a scaled FJH system 673 previously reported [Zhang 2024}. [Wyss 2023], (FIG. 61 shows FG production rate plotted as a function of system energy efficiency, comparing using a single Amico Electric arc welder (1 AW) 683, 2 Amico Electric welders in series (2 SAW) 684, and the TDK Lambda power supply (PS) 685 with this scaled reactor compared to scaled FJH systems 681-682 previously reported [respectively, Zhang 2024; Deng 2023]). The error bars in FIG. 6H from the commercial FJH systems 671-672 illustrate the range of production rates quoted by ACS Materials LLC for these FJH models. The cost of the clay pot, the turning platform, the electrodes, and all arc welder parts are included in these values. The dotted line illustrate the cost and production rate of duplicating each system. For example, having 2 AWs and 2 flowerpot reactor systems running concurrently would cost $520 and produce 6 kg / h MCFG at $200 / tonne (TABLE VII) for starting material and electrical costs of the flashing step, which is superior cost efficiency relative to using a single reactor system with 2 SAW at $530 and 5 kg / h. Also note that in industry, they are unlikely to use arc welders. Much larger systems will likely be required. While the work here can easily provide kilograms of material to laboratories.[Eddy 2023; Zhu 2024}.TABLE VIICost Breakdown of 1 tonne Metallurgical Coke Flash Graphene ($198,08) Input Type Cost (USD) Reference 1.05 tonne metallurgical coke 94.73 [Alibaba 12024}6000 MJ (1667 kWh) electricity 103.35 [US EIA II 2024} Cost analysis was performed assuming a 95 wt% carbon content inside metallurgical coke.[Eddy 2023}. The electricity price was obtained from the average industrial price of electricity in Texas, where this work was performed, during June 2024. This value is $0.062 / kWh. [US EIA II 2024].Attorney Docket No.: 072174-06701 Inorganic Synthesis Reactor

[0141] FJH has also been used in the synthesis of 22 inorganic compounds, primarily transition metal dichalcogenides (TMDs) and p-block metal dichalcogenides (PMDs), through a method called flash-within-flash synthesis. [Choi 2024}. By this technique, inorganic reactants are filled inside an inner quartz tube, which is then surrounded by a feedstock such as MC, before being inserted into another quartz outer tube and closed at the end with electrodes, usually made of graphite. The outer tube undergoes a conventional FJH reaction in which electrical current passes through the MC, heating it. This hot MC then passes heat to the inner tube and its inorganic feedstock contents through thermal conduction. Current does not need to flow through the inorganic feedstock contents of the inner tube in this process, and thus this inorganic feedstock is not restricted to any electrical resistivity boundaries typical of conventional FJH.

[0142] During the flash-within-flash reaction, the reactant feedstocks are decomposed during heating, and the TMDs or PMDs products are formed in kinetically controlled reaction conditions at -1500-2000 °C. [Choi 2024], Based on this, a flash-within-flash reaction was performed using the scaled reactor technique (FIGS. 15A-15I) and prepared 9 quartz tubes: 5 loaded with 0.4 g SnCl₂·2H₂O plus 1.0 g Se powder and 4 loaded with 0.4 g SnCl₂·2H₂O and 1.0 g S powder for a total of 12.6 g of feedstock. These tubes were embedded in the MC until completely covered in a nonagonal pattern around the center electrode. FIG. 15A (with arrows point to the tubes that are visible); FIG 15B.

[0143] The mixture was then subjected to FJH using an analogous technique to that shown in FIG. 6A-6I in which the arc welder electrodes moved in a circular motion around the quartz tubes, FJH the MC and hence transferring this heat through thermal conduction to the tubes.

[0144] The result of this 1-min synthesis was 5 tubes each containing -0.2 g SnS2 and 4 tubes each containing -0.15 g SnSe2 products (FIG 15C (plots 1521-1522 for SnSe2 and SnS2,Attorney Docket No.: 072174-06701 respectively; FIGS. 15D-15F (for SnSe₂); FIGS. 15G-15I (for SnS₂)), amounting to a PMD production rate of 100 g h-1. The versatility of this scaled FJH reactor distinguishes it as a viable inorganic reactor by which several different inorganic products can be simultaneously synthesized. Furthermore, the value of the FG byproduct produced around these tubes offsets the cost of these reactions such that the inorganic products are synthesized at a negative net cost.Applications / Advantages

[0145] Commercial power supplies, especially arc welders, provide a less expensive, more accessible, standardized, more scalable, and more temperature controllable alternative to conventional FJH systems. TABLE II. This facilitates FJH synthesis, especially in reactions requiring greater temperature controllability and those that require sustained heating over longer durations of seconds or minutes. Innate pulse width-modulation in the arc systems reduces the energy requirement to synthesize high-quality FG relative to systems using unmodulated direct current. Pairing these systems with another reaction geometries and systems also enables facile larger scale synthesis by FJH to kilogram scale (Figure S55), even in the open air since outgassing prevents oxidative degradation.

[0146] The scaled flash Joule heating reactor of the systems and methods facilitates the facile, tunable, and scaled production of high-value materials such as graphene, CNTs, PMDs, and TMDs. It also provides a method to upcycle low value materials, such as plastic waste and metallurgical coke, to these higher value products. Graphene and CNTs are widely used in composite materials and batteries, while PMDs and TMDs are widely used in semiconducting devices.

[0147] These systems and methods provide the first kilogram-scale flash Joule heating reaction vessel method by which heating is uniform, which has import for scaling-up further. These systems and methods also provide the first reaction vessel enabling use of the flash within aAttorney Docket No.: 072174-06701 flash method for the simultaneous synthesis of multiple PMD and TMD products. An inexpensive methods to make kilograms of graphene and other flash Joule heated materials. The outgassing shields the material from oxidative decomposition at these high temperatures.

[0148] This system does not require compression of the sample. Unlike other routes which compress the sample between electrodes, here this is no compression required. While one could put a compression screen over the top and force the granules of reactant together to change the resistance, here there is no such requirement. The loose granules can be fed into a reactor and flash Joule heated as needed.

[0149] While embodiments of the invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. The embodiments described and the examples provided herein are exemplary only, and are not intended to be limiting. Many variations and modifications of the invention disclosed herein are possible and are within the scope of the invention. The scope of protection is not limited by the description set out above, but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims.

[0150] The disclosures of all patents, patent applications, and publications cited herein are hereby incorporated herein by reference in their entirety, to the extent that they provide exemplary, procedural, or other details supplementary to those set forth herein.

[0151] Amounts and other numerical data may be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a numerical range of approximately 1 to approximately 4.5 should be interpreted to include not only the explicitly recited limits of 1 to approximately 4.5, but also to include individualAttorney Docket No.: 072174-06701 numerals such as 2, 3, 4, and sub-ranges such as 1 to 3, 2 to 4, etc. The same principle applies to ranges reciting only one numerical value, such as “less than approximately 4.5,” which should be interpreted to include all of the above-recited values and ranges. Further, such an interpretation should apply regardless of the breadth of the range or the characteristic being described.

[0152] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently disclosed subject matter belongs. Although any methods, devices, and materials similar or equivalent to those described herein can be used in the practice or testing of the presently disclosed subject matter, representative methods, devices, and materials are now described.

[0153] Following long-standing patent law convention, the terms “a” and “an” mean “one or more” when used in this application, including the claims.

[0154] Unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter.

[0155] As used herein, the term “about” and “substantially” when referring to a value or to an amount of mass, weight, time, volume, concentration or percentage is meant to encompass variations of in some embodiments ±20%, in some embodiments ±10%, in some embodiments ±5%, in some embodiments ±1%, in some embodiments ±0.5%, and in some embodiments ±0.1% from the specified amount, as such variations are appropriate to perform the disclosed method.

[0156] As used herein, the term “substantially perpendicular” and “substantially parallel” isAttorney Docket No.: 072174-06701 meant to encompass variations of in some embodiments within ±10° of the perpendicular and parallel directions, respectively, in some embodiments within ±5° of the perpendicular and parallel directions, respectively, in some embodiments within ±1° of the perpendicular and parallel directions, respectively, and in some embodiments within ±0.5° of the perpendicular and parallel directions, respectively.

[0157] As used herein, the term “and / or” when used in the context of a listing of entities, refers to the entities being present singly or in combination. Thus, for example, the phrase “A, B, C, and / or D” includes A, B, C, and D individually, but also includes any and all combinations and subcombinations of A, B, C, and D.REFERENCES

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Claims

Attorney Docket No.: 072174-06701 WHAT IS CLAIMED IS:

1. A method comprising:(a) adding a conductive medium in a thermally resistive reaction vessel, wherein (i) the conductive medium, and(ii) a first electrode and a second electrode are positioned in the conductive medium within the thermally resistive reaction vessel; and(b) performing a flash Joule heating process, wherein(i) a voltage is applied across the first electrode and the second electrode to enable electric current to flow between the first electrode and the second electrode and through the conductive medium, and(ii) the conductive medium is not under compression within the thermally resistive reaction vessel during the flash Joule process.

2. The method of Claim 1, wherein the conductive medium comprises a carbon material.

3. The method of any of Claims 1-2, wherein the conductive medium has a conductivity in a range between 10-3S / cm and 102S / cm.

4. The methods of Claim 3, wherein the conductivity of the conductive medium is in the range between 2 x 10-3S / cm and 102S / cm.

5. The method of any of Claims 1-4 further comprising performing a mixing process to mix the conductive medium during the flash Joule heating process.Attorney Docket No.: 072174-06701 6. The method of Claim 5, wherein the mixing process is selecting from the group consisting of vibrating processes, shaking processes, turning processes, rotating platform processes, stirring processes, mobile electrode processes, and combinations thereof.

7. The method of any of Claims 1-6, wherein the performing of the mixing process provides for uniform heating over the conductive medium.

8. The method of any of Clams 1-7, wherein the voltage is applied using a heating method selected from the group consisting of (a) utilizing a power supply in series, (b) utilizing a power supply in parallel, (b) utilizing exactly one pair of electrodes, (d) utilizing more than one pair of electrodes, (e) utilizing a main electrode and at least two more satellite electrodes, wherein the first electrode that is the main electrode and the second electrode is one of the at least two satellite electrodes, and (f) combinations thereof.

9. The method of any of Clams 1-8, wherein(a) the first electrode comprises a first material selected from the group consisting of graphite, tungsten carbide, silicon carbide, lanthanated tungsten, steel, iron, graphene, metals, metallic alloys, metal composites and / or alloys, and combinations thereof;(b) the second electrode comprises a second material selected from the group consisting of graphite, tungsten carbide, silicon carbide, lanthanated tungsten, steel, iron, graphene, metals, metallic alloys, metal composites and / or alloys, and combinations thereof.Attorney Docket No.: 072174-06701 10. The method of any of Claims 1-9, wherein(a) the method produces a product as a result of the flash Joule heating process; and (b) the product is selected from the group consisting of graphene, turbostratic graphene, ordered graphene, ordered graphite, graphite, carbides, carbyne, carbon nanotubes (CNTs), carbon nanofibers, bamboo-like carbon nanotubes, boron nitride nanotubes, boron nitride carbide nanotubes, boron phosphide nanotubes, boride whiskers, carbide whiskers, nitride whiskers, phosphide whiskers, inorganic whiskers, BxNyCz whiskers, BxNyCz nanotubes, silicon carbide whiskers, boron carbide whiskers, bottle-brush nanotubes, bottle-brush fibers, nanotubes templated on carbon fiber, nanowhiskers templated on carbon fiber, p-block metal dichalcogenides (PMDs), transition metal dichalcogenides (TMDs), one-dimensional PMDs, one-dimensional TMDs, MoS2nanotubes, WS2nanotubes, inorganic compounds, inorganic complexes, organometallic compounds, metal carbides, MAXs, MXenes, flash ID materials, and combinations thereof.

11. The method of any of Claims 1-9, wherein(a) the method produces a gaseous product as a result of the flash Joule heating process;(b) the method further comprises capturing and recovering the gaseous product; and (c) the gaseous product is selected from the group consisting of hydrogen (H2), carbon monoxide, syngas, carbon dioxide, alkane gases, hydrocarbon gases, oxygenated hydrocarbons, oxygenated volatile organic compounds, chlorine, bromine, fluorine, iodine, hydrogen chloride, hydrogen bromide, hydrogen fluoride, mixed halogen gases, and combinations thereof.Attorney Docket No.: 072174-0670112. The method of any of Claims 1-11, wherein the flash Joule heating process is selected from the group consisting of (a) synthesizing graphene by the flash Joule heating, (b) synthesizing carbides by flash Joule heating, (c) synthesizing flash ID materials, (d) flash-within-flash (FWF) Joule heating, (e) flash Joule heating of fiber reinforced plastic, and (f) high-energy flash Joule heating synthesis methods.

13. The method of any of Claims 1-12, wherein the thermally resistive reaction vessel comprises a material having a characteristic selected from the group consisting of low thermal conductivity, low thermal expansion coefficient to reduce thermal shock, high melting point, opacity to visible and IR light, clay, brick, concrete, fire brick, ceramic, mullite, and combinations thereof.

14. The method of any of Claims 1-13, wherein the conductive medium comprises a conductive carbon material having a conductivity of at least 10'3S / cm.

15. The method of any of Claims 1-13, wherein the conductive medium comprises a non-conductive carbon having a conductivity of at most 10'3S / cm.

16. The method of any of Claims 1-15, wherein the conductive medium comprises a conductive additive.

17. The method of any of Claim 1-16, wherein the conductive medium comprises a catalyst.Attorney Docket No.: 072174-06701 18. The method of Claim 17, wherein the catalyst is selected from the group consisting of ferric chloride, ferrocene, nickel chloride, cobalt oxide, cobalt chloride, metalloid, transition metal, main group metal, organometallic, polyoxometalate, metal halide, metal oxide, metal sulfide, metal chalcogenide, and compounds thereof.19 A method comprising:(a) adding a conductive medium in a reaction vessel, wherein(i) the reaction vessel is a conductive vessel operable as a first electrode, and(ii) a second electrode is positioned in the conductive medium within the reaction vessel; and(b) performing a flash Joule heating process, wherein(i) a voltage is applied across the first electrode and the second electrode to enable electric current to flow between the first electrode and the second electrode and through the conductive medium, and(ii) the conductive medium is not under compression within the reaction vessel during the flash Joule process.

20. A system that is operable to perform a method selected from the group consisting of the methods of Claims 1-19.

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