Silicon carbide nanowires on carbon species and methods of making and using thereof

Abstract

Silicon carbide nanowires on carbon species and methods of making and using thereof, and, more particularly, silicon carbide nanowires on coal, graphene, graphite, and fibrous carbon species and methods of making and using thereof. Flash Joule heating and / or microwave reactions are performed in which silicon carbide nanotubes are grown on the surface of a coal-based feedstock, a carbon fiber-based feedstock, or a graphene or graphite feedstock derived from coal or carbon fiber.

Description

Attorney Docket No.: 072174-07601SILICON CARBIDE NANOWIRES ON CARBON SPECIES AND METHODS OF MAKING AND USING THEREOFCROSS-REFERENCED TO RELATED PATENT APPLICATIONS

[0001] The application claims priority to U.S. Patent Appl. Serial No. 63 / 699,571, entitled “Silicon Carbide Nanowires On Carbon Species And Methods of Making and Using Thereof,” to James Mitchell Tour, etal., filed September 26, 2024, which patent application is commonly owned by the owner of the present invention and is incorporated herein in its entirety

[0002] The application related to PCT Patent Application No. PCT / US24 / 48588, entitled “Ultrafast Flash Joule Heating Synthesis Methods and Systems For Performing Same,” to James Mitchell Tour, et cd., filed September 26, 2024 (the “Tour ’588 PCT Application”), which claims priority to U.S. Patent Appl. Serial No. 63 / 585,465, to James Mitchell Tour, et al., entitled “Ultrafast Flash Joule Heating Synthesis Methods and Systems For Performing Same,” filed September 26, 2023. These patent applications are commonly owned by the owner of the present invention and are incorporated herein in its entirety.TECHNICAL FIELD

[0003] The present invention relates to silicon carbide nanowires on carbon species and methods of making and using thereof, and, more particularly, silicon carbide nanowires on coal, graphene, graphite, and fibrous carbon species and methods of making and using thereof.GOVERNMENT INTEREST

[0004] This invention was made with government support under Grant No. FA9550-22-1- 0526, awarded by the United States Air Force Office of Scientific Research, and Grant No. ERDC W912HZ-21-2-0050 and W912HZ-24-2-0027, awarded by the United States Engineer Research and Development Center for the United States Army Corps of Engineers. The United States government has certain rights in the invention.BACKGROUND

[0005] Flash Joule heating (FJH) is a technique by which an electrical current flows through aAttorney Docket No.: 072174-07601 feedstock to rapidly heat it and induce a chemical reaction. This method has been used to convert a variety of carbon-based feedstocks, including coal, into turbostratic flash graphene. [Chen 2021,' Stanford 2020,' Advincula 2021,' Algozeeb 2020,' Luong 2020}. Silicon carbide can also be formed by flash Joule heating a mixture of a silicon-containing feedstock and a carbon-containing feedstock. [Cheng 2024}. Additionally, nanotubes and other ID morphologies can be grown by flash Joule heating a feedstock in the presence of a metal catalyst.

[0006] For example, carbon nanotubes can be grown by flash Joule heating a carbon feedstock in the presence of ferrocene, iron(III) chloride, or other metal catalysts. [Wyss 2023}. Silicon carbide nanofibers can be similarly grown by flash Joule heating a silicon-containing feedstock and a carbon-containing feedstock in the presence of a catalyst. The advantage of using flash Joule heating in these synthesis pathways lies in the energy efficiency, short timescale, and scalability of this technique. Furthermore, these valuable products can be made by flash Joule heating even with waste or low-value feedstocks.

[0007] Previous work on flash Joule heating to produce hybrid and mixed materials has been limited, since flash Joule heating reactions often produce uniform products. For example, the production of flash graphene has been extensively studied, and the production of silicon carbide from flash Joule heating is recently established by Tour et al. [Tour ’030 PCT Application,' Deng 2022} however, the growth of nanotubes, nanowires, whiskers, nanofibers, and other ID structures onto other 2D or 3D structures is new. Tour ’588 PCT Application, filed concurrent herewith, provides for the production of silicon carbide nanowires from a silicon-containing feedstock, a carbon-containing feedstock, and a catalyst. The feedstocks are consumed in such processes, and thus the growth of silicon carbide nanowires onto other surfaces, to make a hybrid morphology, was not then achieved by others. These hybrid morphologies are nonetheless important since they can exhibit significant structural enhancements to concreteAttorney Docket No.: 072174-07601 and other composites when mixed.SUMMARY OF THE INVENTION

[0008] The present invention relates to silicon carbide nanowires on carbon species and methods of making and using thereof, and, more particularly, silicon carbide nanowires on coal, graphene, graphite, and fibrous carbon species and methods of making and using thereof.

[0009] In general, in one embodiment, the invention features a method that includes forming a mixture including a carbon species, a silicon species, and a catalyst. The method further includes heating the mixture to form a first product comprising SiC nanowires on the surface of the carbon species, or graphene or graphite converted from the carbon species. The heating is performed by flash Joule heating or through microwave heating.

[0010] Implementations of the invention can include one or more of the following features:

[0011] The heating can be performed by flash Joule heating.

[0012] The heating can be performed by microwave heating.

[0013] The silicon species can be a non-volatile silicon source.

[0014] The non-volatile silicon source can be selected from the group consisting of sand, silicone oil, iron silicate, diatomite, glass-fiber reinforced plastics, glass fibers, glass, coal fly ash, silica gel, metal silicates, and any combination thereof.

[0015] The silicon species can be a volatile silicon source.

[0016] The volatile silicon source can be silicone oil or gel.

[0017] The silicon source can be from waste comprising silicon.

[0018] The waste can include silicon that is selected from the group consisting of waste glass, silicon wafers, solar panels, and waste construction materials.

[0019] The waste construction materials can be selected from the group consisting of asphalt, brick, and concrete, and pieces, aggregates, and powders of asphalt, brick, and concrete, and combinations thereof.Attorney Docket No.: 072174-07601

[0020] The carbon species can be a non-volatile carbon species.

[0021] The non-volatile carbon species can be metallurgical coke or coal.

[0022] The non-volatile carbon species can be a fibrous carbon species.

[0023] The fibrous carbon species can be carbon fibers made from pitch, polyacrylonitrile, or rayon.

[0024] The fibrous carbon species can be selected from the group consisting of carbon fiber, carbon felt, carbon foam, carbon paper, carbon cloth, and compositions thereof.

[0025] The carbon species can be a volatile carbon species.

[0026] The mixture can further include a volatile carbon species in addition to the non-volatile carbon species.

[0027] The volatile carbon species can be high-density polyethylene.

[0028] The carbon species can be selected from the group of activated carbon, biochar, porous carbon derived from activated carbon, porous carbon derived from biochar, and combinations thereof.

[0029] The catalyst can be selected from the group consisting of ferrocene, iron silicate, iron chloride, iron nitrate, nickel chloride, cobalt chloride, and combinations thereof.

[0030] The catalyst can be selected from the group consisting of metal, metalloid, transition metal, alkali metal, alkaline earth metal, compound, organic compound, inorganic compound, salt, organometallic, polyoxometalate, polymer, complex, and combinations thereof.

[0031] The carbon species and the silicon species can be a carbon and silicon species. (A carbon and silicon species is a species that has carbon atoms and silicon atoms).

[0032] The carbon and silicon species can be coal fly ash or silicon oil.

[0033] The silicon species and the catalyst can be a silicon species catalyst. (A silicon species catalysts is a species that has silicon atoms and catalyst).

[0034] The silicon species catalyst can be iron silicate.Attorney Docket No.: 072174-07601

[0035] The carbon species and the catalyst can be a carbon species catalyst. (A carbon species catalysts is a species that has carbon atoms and catalyst).

[0036] The molar ratio of (a) carbon in the carbon species and (b) silicon in the silicon species can be at least 1 : 1.

[0037] The mixture can include (a) between 60 wt% and 90% wt% carbon; (b) between 10 wt% and 40 wt% silicon; and (c) between 0.01 wt% and 5 wt% of the catalyst.

[0038] During the step of flash Joule heating the mixture, the mixture can have a resistance between 0.5 Q and 50 Q.

[0039] The step of heating can be performed at a temperature between 1800 °C and 2500 °C. The first product can include carbide nanowires.

[0040] The step of heating can be performed at a temperature between 2000 °C and 3000 °C. The first product can include graphene.

[0041] The step of heating can be performed at a temperature between 1000 °C and 2000 °C. The first product can include carbon nanotubes.

[0042] The mixture can include a third element species. The third element can include an element that is not carbon or silicon. (An element species is a species that contains atoms of that element).

[0043] The third species can be selected from the group consisting of boron, aluminum, germanium, tin, gallium, indium, lead, copper, zinc, cadmium, magnesium, titanium, cobalt, tungsten, vanadium, hafnium, niobium, molybdenum, zirconium, and tantalum.

[0044] The third species can include boron.

[0045] The third element species can be the same species as the carbon species, the silicon species, or both.

[0046] The third species can be a different species from the carbon species and the silicon species.Attorney Docket No.: 072174-07601

[0047] A ID material can be grown onto the silicon carbide nanowires.

[0048] The ID material can be selected from the group consisting of nanotubes, nanowires, nano-whiskers, nanofibers, fibrils, and combinations thereof.

[0049] The ID material can be selected from the group consisting of carbon nanotubes, boron nitride nanotubes, boron carbide nanowhiskers, BNC nanotubes, BNC nanowhiskers, silicon boride nanowhiskers, transition metal dichalcogenide nanotubes, and combinations thereof.

[0050] The method can further include forming a second mixture including the first product, a second silicon species, and a second catalyst. The method can further include heating the second mixture to form a second product comprising SiC nanowires on the surface of the carbon species or graphene. The heating the second mixture can be performed by flash Joule heating or through microwave heating.

[0051] The heating the second mixture can be performed by flash Joule heating.

[0052] The heating the second mixture can be performed by microwave heating.

[0053] The second product can include bottle-brush silicon carbide nanowires.

[0054] The second product can include core-shell silicon carbide nanowires.

[0055] In general, in another embodiment, the invention features a product that includes SiC whiskers, nanotubes, nanowires, fibers, and / or fibrils on the surface of a carbon species.

[0056] Implementations of the invention can include one or more of the following features:

[0057] The carbon species can be coal.

[0058] The carbon species can be graphene or graphite.

[0059] The carbon species can be a fibrous carbon species.

[0060] The fibrous carbon species can be carbon fibers made from pitch, polyacrylonitrile, or rayon.

[0061] The fibrous carbon species can be selected from the group consisting of carbon fiber, carbon felt, carbon foam, carbon nanotubes, carbon paper, carbon cloth, and compositionsAttorney Docket No.: 072174-07601 thereof.

[0062] The product can be made by the method of any of the above-described methods.

[0063] In general, in another embodiment, the invention features a method that includes forming a mixture including a carbon species, a second species, and a catalyst. The method further includes heating the mixture to form a first product comprising one-dimensional materials on the surface of the carbon species, or graphene or graphite converted from the carbon species. The heating is performed by flash Joule heating or through microwave heating. The one-dimensional materials include the carbon species and the second species.

[0064] Implementations of the invention can include one or more of the following features:

[0065] The method can further include forming a second mixture comprising the first product, a third species, and a second catalyst. The method can further include heating the second mixture to form a second product including one-dimensional materials on the surface of the carbon species or graphene.

[0066] The heating of the second mixture can be performed by flash Joule heating or through microwave heating. The one-dimensional materials can include the carbon species and the third species.

[0067] The second species and the third species can be the same species.

[0068] The second species and the third species can be different species.

[0069] The catalyst and the second catalyst can be the same catalyst.

[0070] The catalyst and the second catalyst can be different catalysts.

[0071] The second species can be selected from the group consisting of boron, silicon, aluminum, germanium, tin, gallium, indium, lead, copper, zinc, cadmium, magnesium, titanium, cobalt, tungsten, vanadium, hafnium, niobium, molybdenum, zirconium, and tantalum.

[0072] The third species can be selected from the group consisting of boron, silicon, aluminum,Attorney Docket No.: 072174-07601 germanium, tin, gallium, indium, lead, copper, zinc, cadmium, magnesium, titanium, cobalt, tungsten, vanadium, hafnium, niobium, molybdenum, zirconium, and tantalum.

[0073] The one-dimensional materials can be selected from the group consisting of whiskers, nanotubes, nanowires, fibers, fibrils, and combinations thereof.

[0074] The one-dimensional materials can include a material selected from the group consisting of carbide, boride, nitride, boronitride, borocarbide, BNC, oxynitride, carbonitride, oxide, dioxide, sulfide, disulfide, selenide, diselenide, telluride, ditelluride, phosphide, oxycarbide, oxyboride, oxynitridecarbide, oxybori denitride, oxycarbideboride, OBNC, arsenide, antimonide materials, and combinations thereof.

[0075] The one-dimensional materials can include an inorganic compound. The inorganic compound can include a first element or compound selected from the group consisting of boron, silicon, carbon, aluminum, germanium, tin, gallium, indium, lead, copper, zinc, cadmium, magnesium, titanium, cobalt, tungsten, vanadium, hafnium, niobium, molybdenum, zirconium, tantalum, and combinations thereof. The inorganic compound can include a second element or compound selected from the group consisting of C, B, O, N, S, P, As, Sb, Se, Te, Si, Ge, Sn, I, and combinations thereof.

[0076] The inorganic compound can be selected from the group consisting of transition metal dichalcogenides, mixed chalcogen transition metal dichalcogenides, transition metal dichalcogenides containing more than one type of transition metal, III-V compound, II- VI compound, I- VII compound, group IV compound, group IV element, IV-VI compound, and mixtures thereof.

[0077] The catalyst can be an element, salt, polyoxometalate, or organometallic compound that comprises a main group metal, a transition metal, a lanthanide, or an actinide.

[0078] The mixture can further include a growth promotor or modifier containing an element selected from the group consisting of F, S, Se, Cl, Br, I, P, O, or N that is added to the mixtureAttorney Docket No.: 072174-07601 to enhance the growth of one-dimensional structures.

[0079] In general, in another embodiment, the invention features a product that includes SiC coating, whiskers, nanotubes, nanowires, fibers, and / or fibrils on the surface of a carbon species. The product is made by the method of any of the above-described methods.

[0080] Implementations of the invention can include one or more of the following features:

[0081] The SiC coating can cover 10% to 100% of the surface of the carbon species. The SiC whiskers, nanotubes, nanowires, fibers, and / or fibrils can emanate from the SiC coating.

[0082] The SiC coating can be a 3D coating.

[0083] The 3D coating can include SiC particles.BRIEF DESCRIPTION OF THE DRAWINGS

[0084] FIGS. 1A-1B shows the workflow of a scheme for embodiments of the present invention.

[0085] FIG. 2 shows Raman spectra of silicon carbide nanowires (NWs) on coal-derived graphene. The D band (-1348 cm’1) refers to the disorder band from defects in sp2carbon; the G band (-1585 cm’1) is the graphitic band from in-plane vibrations of sp2carbon; the 2D band (-2691 cm’1) is the second-order two-phonon band of graphene; the FTO mode (-746 cm’1) is the folded transverse optical phonon of SiC; and the FLO mode (-946 cm’1) is the folded longitudinal optical phonon of SiC.

[0086] FIGS. 3A-3D are SEM images of silicon carbide nanowires on coal-derived graphene. FIGS. 3A-3B show sample prepared by using a feedstock of desert sand and metallurgical coke with ferrocene. FIGS. 3C-3D show sample was prepared without adding any Fe catalysts.

[0087] FIGS. 4A-4B are SEM images of silicon carbide nanowires / particles composites on coal-derived graphene. First, SiC particles were formed on the metallurgical coke by Joule heating of desert sand and metallurgical coke, without adding Fe catalysts. Then, the sample was Joule-heated again by adding desert sand and ferrocene as the catalyst, which grew the SiCAttorney Docket No.: 072174-07601NWs on the surface of the SiC particles.

[0088] FIGS. 5A-5B are SEM images of silicon carbide nanowires on coal-derived graphene. Sample was prepared by using a feedstock of desert sand and metallurgical coke with Fe(NO3)3.

[0089] FIGS. 6A-6B are SEM images of silicon carbide nanowires on coal-derived graphene. Sample was prepared by using a feedstock of silicone oil and metallurgical coke with ferrocene.

[0090] FIGS. 7A-7B are SEM images of silicon carbide nanowires on coal-derived graphene. Sample was prepared by using a feedstock of diatomite and metallurgical coke with ferrocene.

[0091] FIGS. 8A-8B are SEM images of silicon carbide nanowires on coal-derived graphene. Sample was prepared by using a feedstock of iron silicate and metallurgical coke with ferrocene.

[0092] FIGS. 9A-9B are SEM images of silicon carbide nanowires on coal-derived graphene. Sample was prepared by using a feedstock of oil sand and metallurgical coke with ferrocene.

[0093] FIGS. 10A-10B are SEM images of silicon carbide nanowires on coal-derived graphene. Sample was prepared by using a feedstock of coal fly ash and metallurgical coke with ferrocene.

[0094] FIGS. 11A-11B are SEM images of SEM images of silicon carbide nanowires growing on the surface of carbon felt. Sample was prepared by flash Joule heating carbon felt that was covered with silicone oil mixed with ferrocene.

[0095] FIG. 12 shows X-ray diffractometry analysis of silicon carbide nanowires on coal- derived graphene. (Reference PDF cards are 3C-SiC (#00-029-1129), Graphite (#00-041- 1487), and SiCh (#01-077-8621), respectively).

[0096] FIG. 13 shows XRD patterns of MetCoke-iron silicate prepared by Joule heating.

[0097] FIG. 14 shows XRD patterns of MetCoke-oil sand prepared by Joule heating.

[0098] FIG. 15 shows XRD patterns of MetCoke-coal fly ash prepared by Joule heating.

[0099] FIGS. 16A-16B show SEM images of silicon carbide nanowires on coal-derivedAttorney Docket No.: 072174-07601 graphene. Sample was prepared by using a feedstock of silicone oil and metallurgical coke with ferrocene, heated in a microwave for 10 min.

[0100] FIGS. 17A-17B show SEM images of silicon carbide nanowires on coal-derived graphene. Sample was prepared by using a feedstock of desert sand and metallurgical coke with ferrocene, heated in a microwave for 10 min.

[0101] FIGS. 18A-18B show Raman spectra of silicon carbide nanowires on coal-derived graphene. FIG. 18A: Sample was prepared by using a feedstock of silicone oil and metallurgical coke with ferrocene, heated in a microwave for 10 min. FIG. 18B: Sample was prepared by using a feedstock of desert sand and metallurgical coke with ferrocene, heated in a microwave for 10 min.

[0102] FIGS. 19A-19J show ultrafast carbothermal synthesis of SiC nanowires from metallurgical coke (MC) (also known as “MetCoke”) and desert sand. FIGS. 19A-19B are digital photographs of solid precursors metallurgical coke (MC) and desert sand, respectively. Scale bar = 1 cm. FIGS. 19C-19D show XRD patterns of MC and the sand, respectively. FIGS. 19E-19F are photographs of the packed quartz tube before current application and during flash- Joule heating, respectively. Scale bar = 2 cm. FIG. 19G shows time-temperature profile recorded with a pyrometer at the tube center. FIG. 19H shows calculated Gibbs free-energy change for the global reaction SiCh + 3 C — > SiC + 2 CO(g). FIG. 191 shows a schematic of the quartz reaction tube loaded with a homogeneous mixture of MC, sand, and an Fe precursor (ferrocene) contacted by graphite electrodes. FIG.19J shows a proposed Fe-assisted vaporliquid-solid (VLS) mechanism: gaseous SiO gradually reduces and dissolves in Fe-C droplets on MC, followed by precipitation of P-SiC NWs.

[0103] FIGS. 20A-20I show structural and compositional evidence for Fe-catalyzed formation of P-SiC nanowires on metallurgical coke (MC). FIG. 20A shows an optical image of MC particles after the flash process, showing a slight blue sheen. Scale bar = 2 cm. FIG. 20B showsAttorney Docket No.: 072174-07601 an SEM of a reacted particle. Scale = 400 pm. FIG. 20C shows a higher-magnification SEM revealing dense mats of long, ultrathin SiC nanowires. Scale = 2 pm. FIG. 20D shows SEM- EDS line mapping of a single NW; Si and C are co-distributed, with minor O. Scale = 1 pm. FIG. 20E shows corresponding EDS spectrum. FIG. 20F shows a high-resolution TEM of a representative NW. Lattice fringes with d = 0.25 nm index to the (111) planes of cubic P-SiC (3C). Scale = 20 nm. FIG. 20G shows powder XRD pattern of the SiC NWs growth on MC. FIG. 20H shows Raman spectrum of SiC / MC samples. FIG. 201 shows XPS Si 2p region.

[0104] FIGS 21A-21C show mechanical performance of lightweight mortars using met-coke- derived SiC-nanowire aggregates. FIG. 21A shows bulk density of the fresh / hardened mortars using natural aggregate, MC, and SiC / MC as aggregate. FIG. 21B shows a schematic of the tensile splitting tensile test: a cylindrical specimen is loaded between bearing strips. FIG. 21C shows tensile splitting strength at 3rd, 7th, and 28thday for sand (control), MC, and SiC / MC mortars.

[0105] FIGS. 22A-22B show thermodynamics and off-gas during SiC NWs synthesis using the silicone oil. FIG. 22A shows calculated Gibbs free energy for thermal decomposition of the PDMS repeat unit (Si(CH3)2O) shows AG < 0 across the experimental window. FIG. 22B shows GC of the off-gas collected during flashing exhibits a prominent EE peak.

[0106] FIGS 23A-23F show flowerpot scale-up of the flash carbothermal process. FIG. 23A shows a schematic of a refractory flowerpot packed with a homogeneous mixture of MC, Si- bearing precursor, and Fe catalyst, contacted by opposed graphite electrodes. FIG. 23B shows a photograph during operation showing bright incandescence of the packed bed under direct current. Scale = 10 cm. FIG. 23C shows an SEM of reacted MC particles, revealing a fused, porous crust. Scale = 200 pm. FIG. 23D shows an SEM of SiC NWs on the surface of MC. Scale = 5 pm. FIG. 23E shows powder XRD confirming P-SiC (3C) as the dominant crystalline phase. FIG. 23F shows Raman spectrum exhibiting the SiC TO features together withAttorney Docket No.: 072174-07601 sharpened D / G (and 2D) bands of graphitized carbon.DETAILED DESCRIPTION

[0107] The present invention relates to silicon carbide nanowires on carbon species and methods of making and using thereof, and, more particularly, silicon carbide nanowires on coal, graphene, graphite, and fibrous carbon species and methods of making and using thereof. Flash Joule heating and / or microwave heating reactions are performed in which silicon carbide nanowhiskers are grown on the surface of a coal-based feedstock, a carbon fiber-based feedstock, or a graphene or graphite feedstock derived from coal or carbon fiber.

[0108] Embodiments of present invention include performing a conventional flash Joule heating and / or microwave heating reaction on a feedstock having a low-cost silicon-containing feedstock, such as sand or even cheaper desert sand, a carbon-containing feedstock, such as a coal -derived or fibrous carbon feedstock, and a catalyst to facilitate the growth of nanotubes or nanowires or nanowhiskers. When this heating reaction is formed on a non-volatile form of carbon, such as coal or a pyrolyzed fibrous carbon species, then silicon carbide nanowires grow onto the surface of the coal or fibrous carbon species. These carbon feedstocks can also be converted into turbostratic flash graphene or graphite when the reaction temperature exceeds -2000 °C, and thus the product would be silicon carbide nanowires grown on top of graphene or graphite derived from coal or from fibrous carbon. These silicon-carbide-carbon hybrid structures can be mixed into concrete, mortar, cement, plastic, epoxy or other composites to result in an improvement in the physical properties of the composite, including the tensile strength and elastic modulus. Additionally, valuable fuel gases, such as syngas and others can be captured during the heating formation of these structures.FJH Synthesis of Silicon Carbide Nanowires on Carbon or Graphene

[0109] Processes of the present invention utilized flash Joule heating technology. A typical workflow of this new flash Joule heating process is shown in the workflow shown in FIGS.Attorney Docket No.: 072174-076011A-1B. As shown in FIG. 1 A, a non-volatile carbon species 101 is mixed with a silicon species 102 and a catalyst 103. The flash Joule heating of the mixture results in silicon carbide nanowires grown onto the surface of the carbon species, or graphene (product 104) converted from the carbon species. As shown in FIG. IB, product 104 can then be reused and remixed with a silicon species 112 and a catalyst 113 to growth bottle-brush tube or wire structures or core-shell tube or wire structures (product 114).

[0110] For embodiments, the target reactant feedstock is selected. This feedstock includes three components: a silicon-source (silicon species 102), a non-volatile carbon source (carbon species 101), and a nanowire catalyst (catalyst 103). A single feedstock can contain all these components, or multiple feedstocks may be mixed together.[OHl] The silicon source (silicon species 102) may be a solid, non-volatile silicon source, such as sand, like desert sand, or a volatile silicon source, such as silicone oil or gel. Silicon sources can also include waste construction materials, such as asphalt, brick, and concrete, and pieces, aggregates, and powders of asphalt, brick, and concrete, and combinations thereof. For instance, brick powder has been used in embodiments of the present invention.

[0112] The carbon source (carbon species 101) is a non-volatile carbon source so that the source will not be consumed in the flash Joule heating reaction. This has import for the SiC nanowires to grow on top of this source. A carbon source that can commonly be used is metallurgical coke or coal. The fibrous carbon species can be carbon fibers made from pitch, polyacrylonitrile, or rayon. It can also be a fibrous carbon species, such as carbon fiber, carbon felt, carbon foam, carbon paper, or carbon cloth.

[0113] A volatile species of carbon may be used in addition to the non-volatile species of carbon to provide additional carbon atoms for the growth of SiC nanowires, but the nanowires will not grow onto this volatile species. For example, plastic is a “volatile carbon species” since it decomposes at a low temperature, and so fewer wires can effectively grow onto itsAttorney Docket No.: 072174-07601 surface. For example, high-density polyethylene, a type of plastic, decomposes at -400 °C. If a fibrous carbon species is used, then it may be simply wetted with a silicone oil.

[0114] The nanowire catalyst (catalyst 103), such as, for example, ferrocene or iron(III) chloride, is used to facilitate the growth of nanowires or nanotubes. Without such a catalyst, the product would not have a nanotube, nanowire, or other ID morphology. If silicone oil is used, then the catalyst generally should be mixed into the oil first.

[0115] Some feedstocks individually contain multiple of the required components, reducing the required number of separate feedstocks. For example, coal fly ash and silicone oil contain both carbon and silicon. Likewise, iron silicate contains both silicon and iron for a catalyst.

[0116] A mass ratio of the component feedstocks can be chosen. Optimal growth typically requires the molar ratio of carbon to exceed that of silicon, since silicon carbide (50 at% Si, 50 at% C) is grown onto a carbon source. For instance, in some embodiments, a mass mix of -60- 90 wt% carbon content, -10-40 wt% silicon feedstock, and -0.01-5 wt% catalyst feedstock can be chosen. One typical mix is 66 wt% metallurgical coke, 33% desert sand, 1 wt% ferrocene For growth onto fibrous carbon species, a typical mix is 33.2 wt% carbon felt, 66.4 wt% silicon oil, and 0.4 wt% ferrocene. Desert sand is preferred since it is much cheaper than riverbed sand or washed ocean sand, but all three sand types will work.

[0117] The mix can also fall within an electrical resistance range suitable for flash Joule heating of -0.5-50 Q. This resistance constraint can be overcome by performing flash within flash Joule heating. [Tour ’780 PCT Application,' Choi 2024}.

[0118] To perform the flash Joule heating process, the reactant feedstock can be placed in a quartz tube and sealed at the ends of the tube with electrodes. For instance, the quartz tube is conventionally 8 mm in interior diameter a 4-10 cm in length for 200 mg-1 g scale reactions. For larger scale reactions in the 1-10 g range, a 25 mm diameter quartz tube can be used. The electrodes used at the end of the tube are typically graphite.Attorney Docket No.: 072174-07601

[0119] Flash Joule heating is then performed utilizing the reactant feedstock (as shown in FIG. 1A). For example, in nested tubes, the current flows from one of the outer graphite electrodes, through reactant feedstock in the inner tube, to the other graphite electrode. For this size of reaction, energy per mass reactant feedstock of -4-20 kJ / g is typically used to reach an optimal temperature of -1800-2000 °C. Lower energy can be required in both cases when larger reaction vessels are used. The energy must be discharged into the sample at sufficient power to induce this temperature.

[0120] The species grown can be controllable by the reaction temperature. Thus, the reaction temperature can be tuned to target specific products and avoid others. For instance, silicon carbide nanowires can be grown optimally at -1800-2500 °C; graphene can be grown from the coal or fibrous carbon species optimally at -2000-3000 °C; and carbon nanotubes can be grown optimally at -1000-2000 °C. Volatile gases, such as syngas, like H2 gas, may be formed from this flash Joule heating step and can be captured.

[0121] As shown in FIG. 1A, this process results in the growth of SiC nanowires onto the surface of a carbon species, making a hybrid morphology structure 104 (such as silicon carbide nanowires on carbon or graphene) of ID SiC nanowires and 2D structures if graphene or graphite is formed, as well as 3D structures if some of the carbon species is left unconverted to graphene or graphite. Other types of nanotubes, including carbon nanotubes, transition metal dichalcogenide nanotubes, boron carbide nanowhiskers, or others can also be analogously grown onto these carbon species by providing feedstocks containing the atoms also contained in the target ID product. For example, providing a boron source and a catalyst can be used to grow boron carbide nanowhiskers onto these carbon species.

[0122] As shown in FIG. IB, this process can be repeated with the SiC-onto carbon product in order to grow additional nanowires or nanotubes onto the SiC-carbon hybrid product 104. Product 104 is mixed in with a new silicon species (silicon species 112), optionally anotherAttorney Docket No.: 072174-07601 carbon species, and a catalyst (catalyst 113). By reflashing the SiC on carbon product, new SiC nanowhiskers and nanowires grown onto the side of the silicon carbide nanowires (product 114). These are commonly known as bottle-brush structures. This may also result in nanowire or nanotubes growth around the circumference of the silicon carbide nanowires. These are known as core-shell structures.

[0123] Other types of nanotubes, including carbon nanotubes, transition metal dichalcogenide nanotubes, boron carbide nanowhiskers, or others can also be analogously grown onto the sides of these nanowires by providing feedstocks containing the atoms also contained in the target ID product. For example, providing a boron source and a catalyst can be used to grow boron carbide nanowhiskers onto these carbon species.Parameters for SiC Nanowires on Coal, Graphene, and Fibrous Carbon Species

[0124] Parameter for SiC nanowires on coal, graphene, and fibrous carbon species include:

[0125] The feedstock to be flash Joule heated includes (a) a coal product, petroleum product, coal -derived graphene product, fibrous carbon product, or fibrous carbon-derived graphene or graphite product, or other non-volatile species of carbon, (b) a silicon-containing compound, and (c) a catalyst. When these are flash Joule heated together, then silicon carbide nanowires are grown onto a coal species, petroleum-derived species, fibrous carbon species, or graphene or graphite. If the carbon species is volatile, meaning that it has low decomposition temperature, such as plastic, oil, or plant matter, then the nanowires will not effectively grow on its surface. Instead, the nanowires will grow among the graphene, not forming a true hybrid morphology. A volatile species of carbon may be used in addition to a non-volatile species of carbon to provide additional carbon atoms for the growth of SiC nanowires, but the nanowires will not grow onto the volatile species.

[0126] The coal product feedstock can be coal, metallurgical coke, petroleum coke, anthracite coal, silicone oil, coal fly ash, graphene, carbon fibers or graphite derived from any of theseAttorney Docket No.: 072174-07601 sources, or any combination of these.

[0127] The fibrous carbon feedstock can be a carbon felt, cloth, fiber, paper, foam, graphene or graphite derived from any of these sources, or any combination of these.

[0128] The silicon feedstock can be any type of sand, including desert sand, riverbed sand, oil sand, or beach sand; silicone oil, iron silicate, diatomite, glass-fiber reinforced plastics, glass fibers, glass, coal fly ash, silica gel, metal silicates, or any combination of these.

[0129] The catalysts can be ferrocene, iron silicate, iron chloride, iron nitrate, nickel chloride, cobalt chloride, or any combination of these. Other options for catalysts include metal, metalloid, transition metal, alkali metal, alkaline earth metal, compound, organic compound, inorganic compound, salt, organometallic, polyoxometalate, polymer, complex, etc., or any combination of these. The metal may be either a cation, or in a complex cation, or an anion, or complex anion.

[0130] The catalyst can be omitted to grow silicon carbide crystals in a 3D morphology atop or withing or around the carbon source.

[0131] Additional nanotubes, nanowires, nano-whiskers, nanofibers, fibrils, or other ID materials, such as carbon nanotubes, boron nitride nanotubes, boron carbide nanowhiskers, silicon boride nanowhiskers, transition metal di chalcogenide nanotubes, can be grown directly onto the surface of the silicon carbide 3D crystals. This can be achieved by providing feedstock containing the atoms also contained in the target ID product. For example, providing a boron source, such as amorphous boron or boric acid, and a catalyst, such as ferrocene, can be used to grow boron carbide nanowhiskers onto these carbon species.

[0132] Additional nanotubes, nanowires, nano-whiskers, nanofibers, fibrils, or other ID materials, such as carbon nanotubes, boron nitride nanotubes, boron carbide nanowhiskers, silicon boride nanowhiskers, transition metal di chalcogenide nanotubes, can be grown directly onto the coal, coal-derived graphene, or fibrous carbon species, fibrous carbon species-derivedAttorney Docket No.: 072174-07601 graphene, or onto any combination of these. This can be done recursively. This can be achieved by providing feedstock containing the atoms also contained in the target ID product. For example, providing a boron source, such as amorphous boron or boric acid, and a catalyst, such as ferrocene, can be used to grow boron carbide nanowhiskers onto these carbon species.

[0133] Additional nanotubes, nanowires, nano-whiskers, nanofibers, fibrils, or other ID materials, such as carbon nanotubes, boron nitride nanotubes, boron carbide nanowhiskers, silicon boride nanowhiskers, transition metal di chalcogenide nanotubes, or any combination of these, can be grown onto the side of the silicon carbide nanowires. These are commonly known as bottle-brush structures. This can be done recursively. This can be achieved by providing feedstocks containing the atoms also contained in the target ID product. For example, providing a boron source, such as amorphous boron or boric acid, and a catalyst, such as ferrocene, can be used to grow boron carbide nanowhiskers onto these carbon species.

[0134] Additional nanotubes, nanowires, nano-whiskers, nanofibers, fibrils, or other ID materials, such as carbon nanotubes, boron nitride nanotubes, boron carbide nanowhiskers, silicon boride nanotubes, transition metal di chalcogenide nanotubes, or any combination of these, can be grown around the circumference of the silicon carbide nanowires. These are known as core-shell structures. This can be done recursively. This can be achieved by providing feedstock containing the atoms also contained in the target ID product. For example, providing a boron source, such as amorphous boron or boric acid, and a catalyst, such as ferrocene, can be used to grow boron carbide nanowhiskers onto these carbon species. If the carbon feedstock is a porous carbon like that derived from activated carbon or that derived from biochar, the ID structures can grow withing the porous structure of the feedstock.

[0135] An oil or liquid species, including a carbon-based oil or a silicone gel or oil can be used to facilitate the mixing of the other feedstock and catalysts for growth.

[0136] These products can be formed in a single flash Joule heating reaction, or stepwiseAttorney Docket No.: 072174-07601 through multiple separate flash Joule heating reactions.

[0137] The species grown are controllable by the reaction temperature. Thus, the reaction temperature can be tuned to target specific products and avoid others. Silicon carbide nanowires can be grown optimally at -1200-1800 °C; graphene can be grown from the coal or fibrous carbon species optimally at -2000-3000 °C; carbon nanotubes grow can be optimally at -1000-2000 °C; and silicon carbide 3D morphology grows optimally at -1800-2500 °C. In the absence of a catalyst, it grows optimally at -1800-2500 °C.

[0138] These flash Joule heating reactions can be performed using pulsed or continuous, modulated or unmodulated alternating current or direct current. This current can be supplied from a capacitor bank, arc welder, programmable power supply, direct alternating current output from an outlet, or any other electrical source.

[0139] Additionally, valuable fuel gases, such as syngas and others can be captured during the flash Joule heating of these feedstocks.

[0140] This can also be formed through modifications on the flash Joule heating process, such as flash-within-flash Joule heating, as described in Tour ’780 PCT Application. This can also be accomplished using a scaled flash Joule heating reactor, as described in Tour ’535 Application.

[0141] These products can be mixed into concrete, mortar, asphalt, cement, plastic, epoxy, textile, fiber, or other composites, or any mixture of these, in order to change or improve the physical properties of the composites, including the density, elastic modulus, tensile strength, wear resistance, or thermal resistance.

[0142] The processes can also utilize flash Joule heating processes as described in Tour ’967 PCT Application, Tour ’030 PCT Application, and Tour ’588 PCT Application.Characterization of Silicon Carbide Nanowires on Carbon or Graphene

[0143] There are three characterization techniques that effectively discern the differenceAttorney Docket No.: 072174-07601 between turbostratic graphene and ordered graphene / graphite: Raman spectroscopy, scanning electron microscopy (SEM), and X-ray diffractometry (XRD).Raman Spectroscopy

[0144] Raman spectroscopy is a characterization technique commonly used in the characterization of carbon compounds and especially graphene, since graphene exhibits several characteristic peaks that provide information on specifics traits of the graphene, including whether the graphene is formed and the SiC is synthesized. [Luong 2020}.

[0145] As seen in FIG. 2, when there is formation of SiC nanowires (NWs), it exhibited a sharp peak and a shoulder at ~74 cm’1and -946 cm’1, representing the folded transversal (FTO) and longitudinal (FLO) phonon modes of SiC, respectively. At a higher Raman shift range, when metallurgical coke converted to graphene, it exhibited three typical peaks, which are the disorder band (D) at -1348 cm’1, the primary mode of sp2carbon in graphene and graphite (G) at -1585 cm’1, and two phonon lattice vibrational mode (2D) at -2691 cm’1. It is noted that there were no vibrational modes from silicon oxides / quartz, suggesting there was no residues or unreacted sand on the surface of the graphene.SEM

[0146] SEM provides direct observation of the silicon carbide nanowires on the carbon / graphene, allowing the observation of the coverage of silicon carbide nanowires and the morphology of the obtained carbon composites.

[0147] FIGS. 3A-3D illustrates the products of silicon carbide nanowires on coal-derived graphene. FIGS. 3A-3B show the formation of silicon carbide nanowires on the surface of the metallurgical coke-derived graphene particle, with the additives of ferrocene catalysts during the preparation procedures. The surface of the graphene particle is fluffy and suggests the good coverage of silicon carbide nanowires. FIGS. 3C-3D show the formation of silicon carbide particles on the surface of the graphene particle, without adding the Fe catalysts. This indicatedAttorney Docket No.: 072174-07601 that Joule heating can readily control the morphology of silicon carbide on carbon / graphene particles.

[0148] FIGS. 4A-4B shows that by control the synthetic steps, silicon carbide nanowires / particles composites can grow on the surface of silicon carbide particles, with a more complicated morphology. First, SiC particles were formed on the metallurgical coke by Joule heating of desert sand and metallurgical coke, without adding Fe catalysts. Then, the sample was Joule heated again by adding desert sand and ferrocene as the catalyst, which grew the SiC NWs on the surface of the SiC particles.

[0149] FIGS. 5A-5B further show silicon carbide nanowires can grow on the surface of the coal-derived graphene by using Fe(NO3)3 catalysts, instead of using ferrocene. These were prepared by using a feedstock of desert sand and metallurgical coke with Fe(NO3)3.

[0150] In addition, by replacing the silicon resources into silicone oil, diatomite, iron silicate, oil sand (also called tar sand such as found in Alberta, Canada), or coal fly ash, silicon carbide nanowires can be grown on to the surface of the metallurgical coke, as shown in FIGS. 6A-6B (silicone oil: prepared by using a feedstock of silicone oil and metallurgical coke with ferrocene), FIGS. 7A-7B (diatomite: prepared by using a feedstock of diatomite and metallurgical coke with ferrocene), FIGS. 8A-8B (iron silicate: prepared by using a feedstock of iron silicate and metallurgical coke with ferrocene), FIGS. 9A-9B (oil sand: prepared by using a feedstock of oil sand and metallurgical coke with ferrocene and FIGS. 10A-10B (coal fly ash: prepared by using a feedstock of coal fly ash and metallurgical coke with ferrocene).

[0151] The matrix for the nanowires’ growth can be substituted into carbon felt as well. In FIGS. 11A-11B, one can see that a shell of silicon carbide nanowires grew on the surface of the fibers of the carbon felt (prepared by flash Joule heating carbon felt that was covered with silicone oil mixed with ferrocene). FIG. 11A shows the silicon carbide nanowires are visible on the surface of individual fibers of carbon felt. FIG. 11B shows a zoomed-in version of theAttorney Docket No.: 072174-07601 same region shows more clearly the silicon carbide nanowires.XRD

[0152] This interlayer spacing can also be measured and averaged across a wide portion of the sample using XRD, as illustrated in FIG. 12. FIG. 12 shows that prepared samples by using various silicon resources including desert sand, silicone Oil, and diatomite.

[0153] In addition, FIGS. 13-15 show the sample prepared by (FIG. 13) iron silicate, (FIG.14) oil sand, and (FIG. 15) coal fly ash. The measurement of the angle at which this peak occurred provides the average interlayer spacing of the sample. All three samples presented peaks at -26.5°, which represented (002) facet of the graphene / graphite, with a d-spacing of 0.34 nm for all three samples prepared by joule heating, indicating the conversion of metallurgical coke to flash graphene / graphite. Besides, all samples showed a group of peaks at 35.5°, 41.5°, 60.0°, 71.8°, and 75.8°, indicating the (111), (200), (220), (311), and (222) of3C- SiC, respectively, suggesting the successful formation of silicon carbide on coal-derived flash graphene.Microwave Heating Synthesis of Silicon Carbide Nanowires on Carbon or Graphene

[0154] Microwave heating can be utilized as an alternative way to synthesize SiC nanowires on coal-derived graphene (or other carbon species). As can be seen from FIGS. 16A-16B (silicone oil: prepared by using a feedstock of silicone oil and metallurgical coke with ferrocene) and FIG. 17A-17B (desert sand: prepared by using a feedstock of desert sand and metallurgical coke with ferrocene), after heating in a 1250 W kitchen microwave oven for 10 minutes, the coal surface was covered with SiC nanowires.

[0155] In FIGS. 18A-18B (prepared by using a feedstock of silicone oil and desert sand, respectively), Raman spectra further confirmed the formation of SiC (with FTO modes) and flash graphene with a sharp 2D peak.Attorney Docket No.: 072174-07601Utilization Of Metallurgical Coke / Sand In Certain Embodiments

[0156] Metallurgical Coke (MC), which is also referred to as MetCoke (FIG. 19A) can serve three simultaneous functions in embodiments of the present invention, namely as carbon feedstock, intrinsic conductive filler, and growth substrate. X-ray diffraction (XRD) confirms that the MC can be essentially pure turbostratic carbon. FIG. 19C. Desert sand, selected as the silicon source (i.e., the desert sand supplies the SiO?), is highly crystalline quartz (FIG. 19B and FIG. 19D) and is carburized in situ to yield SiC nanowires (NWs).

[0157] After thorough mixing, the two powders are packed into a quartz tube between graphite electrodes. FIG. 19E. Direct-current passage induces rapid resistive heating, producing an incandescent flash. FIG. 19F (with the mixture self-heating resistively to incandescence). As shown in FIG. 19G, pyrometry shows the temperature of the mixture rising to -1800 °C within 30 s, then self-quenching below 1000 °C in 10 s after power cutoff. Thermodynamic calculations in FIG. 19H indicate that the carbothermal reaction SiCh + 3C — > SiC + 2CO(g) becomes spontaneous above -1500 °C. I.e., AG becomes negative above -1500 °C, indicating spontaneous SiC formation under the experimental conditions.

[0158] FIG. 191 shows a schematic of the quartz reaction tube 1984 loaded with a homogeneous mixture of MC 1981, sand 1982, and an Fe precursor 1983 (ferrocene) contacted by graphite electrodes 1985-1986. When an Fe catalyst 1983 (ferrocene, or other salts) is added, SiC predominantly forms one-dimensional NWs via a vapor-liquid-solid (VLS) pathway (FIG. 19J showing spheres 1991-1993 for Si, O, and C, respectively); without Fe, only coarse SiC particles nucleate on the MC surface.

[0159] After FJH treatment in the presence of ferrocene, the jet-black MC particles acquire a slightly blue and white appearance (FIG. 20A), indicative of a thin SiC NW coating. SEM shows that the surface becomes highly fluffy (FIG. 20B, i.e., the formerly dense surface is now porous and “fluffy.”) and, at higher magnification, is carpeted with micrometer-long,Attorney Docket No.: 072174-07601 nanometer-thin SiC NWs (FIG. 20C). STEM-EDS line mapping across an individual wire (FIG. 20D) reveals co-located Si and C signals with only minor oxygen, while the corresponding spectrum (FIG. 20E) detects trace Fe, corroborating its catalytic role. (FIG. 20E shows corresponding EDS spectrum, with strong Si and C peaks plus trace Fe, affirming the catalyst’s presence). High-resolution TEM (FIG. 20F) resolves 0.25 nm lattice spacings characteristic of the (111) planes of cubic P-SiC (3C phase).

[0160] Bulk XRD (FIG. 20G) displays sharp P-SiC reflections superimposed on the broad turbostratic-carbon peaks of residual MC. Raman spectroscopy (FIG. 20H) further identifies the SiC transverse-optical (TO) mode at 796 cm'1; concurrently, sharpened D (1355 cm'1), G (1580 cm'1) and emergent 2D (2690 cm'1) bands, signaling enhanced graphitization of the substrate during rapid heating. XPS of the Si 2p region (FIG. 201) is dominated by a Si-C peak at -100.6 eV, manifesting the formation of SiC, with a small Si-0 peak at -103.3 eV, consistent with the slight surface oxidation observed in EDS.

[0161] FIG. 21A shows that replacing natural aggregate (NA, 2.02 g cm'3) with met-coke (MC, 1.47 g cm'3) or SiC NWs covered MetCoke (SiC / MC, 1.62 g cm'3) reduces density by 27.2% and 19.8%, respectively, placing both mixes in the structural-lightweight range (less than 1.85 g cm'3; ACI 213R). Cylindrical specimens were then tested in Brazilian splitting tension, with FIG. 21B showing a schematic of the tensile splitting tensile test: a cylindrical specimen 2112 is loaded (load 2113) between bearing strips (wood 2111). At early ages (3rdand 7thdays), SiC / MC outperforms MC, showing 2.33 vs 2.19 MPa at 3 d (6.4% higher) and 4.05 vs 2.94 MPa at 7 d (37.8% higher); at 28 d it remains slightly higher (5.64 vs 5.52 MPa) and comparable to NA (5.82 MPa). FIG. 21C. This enhancement is consistent with SiC NWs crack-bridging / pull-out. Overall, SiC-NW / MC as aggregates enables a lighter mortar without loss of tensile capacity, increasing the specific splitting tensile strength (strength per unit density) at 28 d by -20.8% vs NA.Attorney Docket No.: 072174-07601Thermodynamic Analysis

[0162] FIGS. 22A-22B show thermodynamics and off-gas during SiC NWs synthesis using the silicone oil. Thermodynamic analysis of the silicone-oil repeat unit [the monomer Si(CHs)2- O was used for the calculation] shows that its thermal decomposition is favorable (AG < 0) across the flash-heating window (FIG. 22A, which indicates spontaneous depolymerization to volatile siloxane / Si-0 species), predicting chain scission to volatile siloxane / Si-0 species with concurrent dehydrogenation.

[0163] Consistent with this, gas chromatography (GC) of the reaction headspace exhibits a prominent H2 peak, confirming in-situ hydrogen evolution. FIG. 22B. This H2 may help maintain a reducing atmosphere that supports SiO-mediated, Fe-assisted growth of P-SiC nanowires and is also a recoverable and valuable by-product that can modestly improve process economics.Scalability

[0164] To assess scalability beyond the quartz-tube geometry, a simple flowerpot reactor fabricated from a commercial refractory pot (clay pot 2301) was implemented. A thoroughly mixed charge of MetCoke 2303, SiCh-bearing feedstock 2304, and a trace Fe precursor was loaded into the pot and contacted by graphite electrodes. FIGS. 23A-23B. Utilizing electrodes 2302, passing direct current through the packed MetCoke particles produced rapid, furnace- free ohmic heating to incandescence. After cooling, the product consisted of granules whose surfaces were transformed into fluffy crusts (FIG. 23C, showing reacted MC particles, revealing a fused, porous crust) and were uniformly carpeted by P-SiC nanowires (FIG. 23D). XRD and Raman (FIGS. 23E-23F, respectively) verified the 3C phase and the concurrent graphitization of residual carbon, mirroring the quartz-tube results. The pot configuration provides a thermally robust, low-cost reactor that tolerates heterogeneous waste feedstocks and supports larger batch sizes without compromising nanowire morphology.Attorney Docket No.: 072174-07601Applications

[0165] Silicon carbide nanowires grown onto carbon species can be an important component in composites including concrete, mortar, asphalt, cement, textile, and epoxy composites to improve the physical properties of those composites. Moreover, methods of the present invention are faster, more energy efficient, and cheaper methods of producing silicon carbide nanowires onto carbon sources than has previously been achieved. Furthermore, previous technology on producing silicon carbide nanowires by flash Joule heating did not achieve its growth onto other structures.

[0166] 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.

[0167] 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.

[0168] 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.: 072174-07601 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.

[0169] 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.

[0170] Following long-standing patent law convention, the terms “a” and “an” mean “one or more” when used in this application, including the claims.

[0171] 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.

[0172] 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.

[0173] As used herein, the term “substantially perpendicular” and “substantially parallel” isAttorney Docket No.: 072174-07601 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.

[0174] 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

[0175] PCT Application No. PCT / US24 / 42780, filed on August 16, 2024, entitled “Methods of Flash-Within-Flash Joule Heating And Systems Thereof,” to J.M. Tour, et al. (" Tour ’780 PCT Application" .

[0176] PCT Application No. PCT / US21 / 52030, filed September 24, 2021, entitled “Ultrafast Flash Joule Heating Synthesis Methods And Systems For Performing Same,” to James M. Tour, et al. C lour ’030 PCT Application")

[0177] PCT Application No. PCT / US 19 / 47967, filed on August 23, 2019, entitled “Flash Joule Heating Synthesis Method and Compositions Thereof,” to J.M. Tour, et al. ("Tour ’967 PCT Application").

[0178] U.S. Patent Application Serial No. 63 / 645,535, filed May 10, 2024, entitled “Scaled Flash Joule Heating Systems And Methods of Using Same,” to J.M. Tour, et al. ("Tour ’535 Application").

[0179] Advincula, P. A., et al., “Flash Graphene from Rubber Waste,” Carbon, 2021, 178, 649-656 ^‘Advincular 2021”).

[0180] Algozeeb, W. A., et al., “Flash graphene from plastic waste,” ACS Nano, 2020, 14,Attorney Docket No.: 072174-0760115595-15604 {‘Algozeeb 2020").

[0181] Chen, W., et al., “Ultrafast and Controllable Phase Evolution by Flash Joule Heating,” ACS Nano, 2021, 15, 11158-11167 {‘Chen 2021”).

[0182] Cheng, Y ., etal., “Flash Upcycling of Waste Glass Fibre-Reinforced Plastics to Silicon Carbide,” Nat Sustain., 2024, 7, 452-462 {‘Cheng 2024”).

[0183] Choi, C. H., et al., “Flash-Within-Flash Synthesis of Gram-Scale Solid-State Materials,” Nature Chem., 2024, doi: 10.1038 / s41557-024-01598-7 {‘Choi 2024”).

[0184] Deng, B., et al., “Phase controlled synthesis of transition metal carbide nanocrystals by ultrafast flash Joule heating,” Nat. Commun., 2022, 13, 262 {‘Deng 2022”).

[0185] Luong, D. X., et al. , “Gram-scale bottom-up flash graphene synthesis,” Nature, 2020, 577, 647-651 {‘Luong 2020”).

[0186] Stanford, M. G., et al., “Flash graphene morphologies,” ACS Nano, 2020, 14, 13691- 13699 {‘Stanford 2020”).

[0187] Wyss, K. M., et al., “Upcycling of waste plastic into hybrid carbon nanomaterials,” Adv. Mater., 2023, 35, 2209621 {‘Wyss 2023”).

Claims

Attorney Docket No.: 072174-07601WHAT IS CLAIMED IS:

1. A method comprising:(a) forming a mixture comprising a carbon species, a silicon species, and a catalyst; and(b) heating the mixture to form a first product comprising SiC nanowires on the surface of the carbon species, or graphene or graphite converted from the carbon species, wherein(i) the heating is performed by flash Joule heating or through microwave heating.

2. The method of Claim 1, wherein the heating is performed by flash Joule heating.

3. The method of Claim 1, wherein the heating is performed by microwave heating.

4. The method of any of Claims 1-3, wherein the silicon species is selected from the group consisting of:(a) a non-volatile silicon source is selected from the group consisting of sand, silicone oil, iron silicate, diatomite, glass-fiber reinforced plastics, glass fibers, glass, coal fly ash, silica gel, metal silicates, and any combination thereof,(b) a volatile silicon source that is silicone oil or gel,(c) a silicon source that is from waste comprising silicon, and(d) combinations thereof.

5. The method of any of Claims 1-4, wherein the carbon species is selected from the groupAttorney Docket No.: 072174-07601 consisting of:(a) a non-volatile carbon species selected from the group consisting of metallurgical coke or coal, a fibrous carbon species, and combinations thereof(b) a non-volatile carbon species comprising high-density polyethylene,(c) a carbon species is selected from the group of activated carbon, biochar, porous carbon derived from activated carbon, porous carbon derived from biochar, and combinations thereof, and(d) combinations thereof.

6. The method of any of Claims 1-5, wherein the catalyst is selected from the group consisting of:(a) catalysts selected from the group consisting of ferrocene, iron silicate, iron chloride, iron nitrate, nickel chloride, cobalt chloride, and combinations thereof,(b) catalyst selected from the group consisting of metal, metalloid, transition metal, alkali metal, alkaline earth metal, compound, organic compound, inorganic compound, salt, organometallic, polyoxometalate, polymer, complex, and combinations thereof, and(c) combinations thereof.

7. The method of any of Claims 1-6, wherein the molar ratio of (a) carbon in the carbon species and (b) silicon in the silicon species is at least 1 : 1.

8. The method of any of Claims 1-7, wherein the mixture comprises (a) between 60 wt% and 90% wt% carbon; (b) between 10 wt% and 40 wt% silicon; and (c) between 0.01 wt% and 5 wt% of the catalyst.Attorney Docket No.: 072174-076019. The method of any of Claims 1-8, wherein(a) the mixture comprises a third element species,(b) the third element comprises an element that is not carbon or silicon, and(c) the third element is selected from the group consisting of boron, aluminum, germanium, tin, gallium, indium, lead, copper, zinc, cadmium, magnesium, titanium, cobalt, tungsten, vanadium, hafnium, niobium, molybdenum, zirconium, and tantalum.

10. The method of any of Claims 1-9, wherein the method further comprises:(a) forming a second mixture comprising the first product, a second silicon species, and a second catalyst; and(b) heating the second mixture to form a second product comprising SiC nanowires on the surface of the carbon species or graphene, wherein(i) the heating the second mixture is performed by flash Joule heating or through microwave heating.

11. The method of Claim 10, wherein the second product comprises bottle-brush silicon carbide nanowires and / or core-shell silicon carbide nanowires.

12. A product comprising SiC whiskers, nanotubes, nanowires, fibers, and / or fibrils on the surface of a carbon species.

13. The product of Claim 13, wherein the product is made by the method of any of Claims 1-11.Attorney Docket No.: 072174-0760114. A method comprising:(a) forming a mixture comprising a carbon species, a second species, and a catalyst; and(b) heating the mixture to form a first product comprising one-dimensional materials on the surface of the carbon species, or graphene or graphite converted from the carbon species, wherein(i) the heating is performed by flash Joule heating or through microwave heating, and(ii) the one-dimensional materials comprise the carbon species and the second species.

15. The method of Claim 14, wherein the method further comprises:(a) forming a second mixture comprising the first product, a third species, and a second catalyst; and(b) heating the second mixture to form a second product comprising onedimensional materials on the surface of the carbon species or graphene, wherein(i) the heating of the second mixture is performed by flash Joule heating or through microwave heating, and(ii) the one-dimensional materials comprise the carbon species and the third species.

16. The method of any of Claims 14-15, wherein the second species is selected from the group consisting of boron, silicon, aluminum, germanium, tin, gallium, indium, lead, copper, zinc, cadmium, magnesium, titanium, cobalt, tungsten, vanadium, hafnium, niobium,Attorney Docket No.: 072174-07601 molybdenum, zirconium, and tantalum.

17. The method of any of Claims 15-16, wherein the third species is selected from the group consisting of boron, silicon, aluminum, germanium, tin, gallium, indium, lead, copper, zinc, cadmium, magnesium, titanium, cobalt, tungsten, vanadium, hafnium, niobium, molybdenum, zirconium, and tantalum.

18. The method of any of Claims 14-17, wherein the mixture further comprises a growth promotor or modifier containing an element selected from the group consisting of F, S, Se, Cl, Br, I, P, O, or N that is added to the mixture to enhance the growth of one-dimensional structures.

19. A product comprising SiC coating, whiskers, nanotubes, nanowires, fibers, and / or fibrils on the surface of a carbon species, wherein the product is made by the method of any of Claims 14-18.

20. The product of Claim 19, wherein(a) the SiC coating covers 10% to 100% of the surface of the carbon species, and(b) the SiC whiskers, nanotubes, nanowires, fibers, and / or fibrils emanate from the SiC coating.

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