Furnace-based thermal-shock systems and methods

Abstract

An assembly for use with a furnace can include a conveyance member, a substrate, and a heating support material. The substrate can have one or more precursors deposited thereon. The conveyance member can be constructed such that at least a portion thereof can be moved between a first and second positions with respect to the furnace. The heating support material can be between the conveyance member and the substrate. The heating support material can support the substrate on the conveyance member. The assembly can be subjected to a thermal shock via the furnace. The thermal shock can be at a temperature of at least 1000 K for a duration of 60 seconds or less. The substrate can be supported on the heating support material and the first portion of the conveyance member during the thermal shock.

Description

[0001] FURNACE-BASED THERMAL-SHOCK SYSTEMS AND METHODS

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS )

[0003] The present application claims the benefit of and priority under 35 U.S.C. § 119(e) to and is a non-provisional of U.S. Provisional Application No. 63 / 554,119, filed February 15, 2024, entitled “Furnace-based Thermal-Shock Synthesis Systems and Methods,” which is hereby incorporated by reference herein in its entirety.

[0004] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0005] This invention was made with government support under DE-AR0001600 awarded by the U.S. Department of Energy. The government has certain rights in the invention.

[0006] FIELD

[0007] The present disclosure relates generally to heating of materials, and more particularly, to processing and / or synthesis of materials by heating in a furnace, for example, by subjecting one or materials (e.g., precursors) to a high temperature (e.g., at least 1000 K) for a short duration (e.g., 60 seconds or less).

[0008] BACKGROUND

[0009] Multi-element nanoparticles have gained significant interest because of their adjustable physical and chemical characteristics, unique combined effects, and entropy stabilization. Conventional methods for producing these nanoparticles typically involve high-temperature synthesis; however, such nanoparticles have been limited to unary, binary, or ternary components, primarily due to the calcination in a furnace (e.g., continuous heating at a temperature of -500- 600 °C for hours) required to decompose a metal precursor. In particular, due to the high temperature and the long duration in conventional furnaces, the metal can react with the substrate to form impurities or second phases, thereby affecting the formation and dispersion of high-quality metal on the nano-scale level.

[0010] HEA nanoparticles have previously been synthesized via thermal shock, for example, as described in U.S. Patent No. 11,193,191, issued December 7, 2021 and entitled “Thermal shock synthesis of multielement nanoparticles,” and U.S. Patent No. 11,369,929, issued June 28, 2022 and entitled “Nanoparticles and systems and methods for synthesizing nanoparticles through thermal shock.” In prior examples of this thermal shock process, synthesis was achieved through a carbothermal shock process, involving ultrahigh temperatures (-2000 K), extremely short pulses (-55 ms), and rapid heating / cooling rates (-104K / s) for metal salt precursor mixtures loaded onto carbon substrates. However, the HEA nanoparticles were formed on carbon substrates, which can limit their practical applications, for example, for reactions conducted under oxidative environments.

[0011] While non-carbon substrates can allow the resulting structure to be used in more diverse catalytic applications, it may also compromise the ability to form multi-element nanoparticles. For example, the use of substrates that are not electrically conductive prevents the substrate from being directly Joule heated, since electric current cannot be passed therethrough. In such cases, heating of the substrate and precursors thereon may be provided by a separate heating element (e.g., within a furnace), for example, via radiative and / or conductive heating. Yet, the ability of conventional furnaces to apply a sufficiently high temperature of short duration to generate a desired thermal shock may be limited, for example, due to thermally-insulating conveyance members (e.g., ceramic boats) used to move the precursor-loaded substrate into / out of a heating zone of the furnace. Such challenges may not be limited to synthesis of HEA nanoparticles. Rather the limitations of carbon-based substrates for Joule heating and / or conventional furnace-based heating systems may also arise in other material synthesis applications, such as, but not limited to, sintering of precursors to form a structure (e.g., one or more layers, films, membranes, etc.).

[0012] Aspects of the disclosed subject matter may address one or more of the above-noted problems and disadvantages, among other things.

[0013] SUMMARY

[0014] Aspects of the disclosed subject matter provide furnace-based thermal shock systems and methods. In some embodiments, one or more materials (e.g., precursors) can be provided (e.g., deposited) on a substrate (e.g., extrudate) and conveyed into and / or through a furnace to subject the substrate to a thermal shock, for example, a high temperature (e.g., at least 1000 K) for a short duration (e.g., 60 seconds or less). In some embodiments, the substrate can be supported on (e.g., in direct contact with) a heating support material, which can enhance heating of the substrate via radiative heating by the furnace, for example, due to a relatively high thermal conductivity (e.g., at least along its length), a relatively low heat capacity, and / or a relatively high emissivity of the heating support material (or a component thereof). In some embodiments, the heating support material can comprise and / or be formed of carbon (e.g., film, paper, mesh, felt, or other structure formed from carbon fibers) or ceramic (e.g., film, paper, felt, or other structure formed from ceramic fibers). In some embodiments, the substrate can be conveyed into and / or through the furnace via a conveyance member (e.g., a ceramic boat), and the heating support material can be between (e.g., in direct contact with) the substrate and the conveyance member.

[0015] In one or more embodiments, an assembly can comprise a substrate, a conveyance member, and a heating support material. The substrate can have one or more precursors thereon. The conveyance member can be constructed such that at least a first portion of the conveyance member is movable between first and second positions with respect to a furnace. The heating support material can be arranged between the first portion of the conveyance member and the substrate. The heating support material can support the substrate on the first portion of the conveyance member.

[0016] In one or more embodiments, a system can comprise a furnace, a substrate, a conveyance member, and a heating support material. The substrate can have one or more precursors thereon. The conveyance member can be constructed such that at least a first portion of the conveyance member is movable between first and second positions with respect to a furnace. The heating support material can be arranged between the first portion of the conveyance member and the substrate. The heating support material can support the substrate on the first portion of the conveyance member.

[0017] In one or more embodiments, a method can comprise providing a heating support material on a first portion of a conveyance member. At least the first portion of the conveyance member can be movable between first and second positions with respect to a furnace. The method can further comprise providing a substrate on the heating support material. The heating support material can be between the first portion of the conveyance member and the substrate. The heating support material can support the substrate on the first portion of the conveyance member. The substrate can have one or more precursors thereon. The method can also comprise subjecting, via the furnace, the one or more precursors on the substrate to a thermal shock. The thermal shock can comprise a temperature of at least 1000 K for a duration of 60 seconds or less. During the subjecting, the substrate can be supported on the heating support material and the first portion of the conveyance member.

[0018] Any of the various innovations of this disclosure can be used in combination or separately. This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. The foregoing and other objects, features, and advantages of the disclosed technology will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.

[0019] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Aspects will hereinafter be described with reference to the accompanying drawings, which have not necessarily been drawn to scale. Where applicable, some elements may be simplified or otherwise not illustrated in order to assist in the illustration and description of underlying features. Throughout the figures, like reference numerals denote like elements.

[0021] FIG. 1 is a simplified schematic diagram illustrating aspects of a furnace-based thermal shock employing a heating support material, according to one or more embodiments of the disclosed subject matter.

[0022] FIG. 2A is a simplified schematic diagram illustrating a furnace-based thermal shock system, according to one or more embodiments of the disclosed subject matter.

[0023] FIG. 2B is a simplified schematic diagram illustrating a furnace-based thermal shock system configured for batch fabrication, according to one or more embodiments of the disclosed subject matter.

[0024] FIG. 2C is a simplified schematic diagram illustrating a furnace-based thermal shock system configured for continuous or semi-continuous fabrication, according to one or more embodiments of the disclosed subject matter.

[0025] FIG. 3 is a simplified schematic diagram illustrating aspects of a tube furnace-based thermal shock system, according to one or more embodiments of the disclosed subject matter.

[0026] FIG. 4 is a process flow diagram illustrating aspects of a method employing a heating support material, according to one or more embodiments of the disclosed subject matter.

[0027] FIG. 5 depicts a generalized example of a computing environment in which the disclosed technologies may be implemented.

[0028] FIG. 6 shows transmission electron microscopy (TEM) images and elemental mappings of AI2O3 extrudates with HEA nanoparticles (PtPdRhCoCe) formed thereon via thermal shock.

[0029] DETAILED DESCRIPTION

[0030] General Considerations

[0031] For purposes of this description, certain aspects, advantages, and novel features of the disclosed subject matter are described herein. The disclosed methods and systems should not be construed as being limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects disclosed herein, alone and in various combinations and subcombinations with one another. The methods and systems are not limited to any specific aspect or feature or combination thereof, nor do the disclosed aspects require that any one or more specific advantages be present, or problems be solved. The technologies from any aspect or example can be combined with the technologies described in any one or more of the other aspects or examples. In view of the many possible aspects to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated aspects of the disclosure are exemplary only and should not be taken as limiting the scope of the disclosed technology. Although the operations of some of the disclosed methods are described in a particular, sequential order for convenient presentation, it should be understood that this manner of description encompasses rearrangement, unless a particular ordering is required by specific language set forth below. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed methods can be used in conjunction with other methods. Additionally, the description sometimes uses terms like “provide” or “achieve” to describe the disclosed methods. These terms are high-level abstractions of the actual operations that are performed. The actual operations that correspond to these terms may vary depending on the particular implementation and are readily discernible by one skilled in the art.

[0032] The disclosure of numerical ranges should be understood as referring to each discrete point within the range, inclusive of endpoints, unless otherwise noted. Unless otherwise indicated, all numbers expressing quantities of components, molecular weights, percentages, temperatures, times, and so forth, as used in the specification or claims are to be understood as being modified by the term “about.” Accordingly, unless otherwise implicitly or explicitly indicated, or unless the context is properly understood by a person skilled in the art to have a more definitive construction, the numerical parameters set forth are approximations that may depend on the desired properties sought and / or limits of detection under standard test conditions / methods, as known to those skilled in the art. When directly and explicitly distinguishing aspects from discussed prior art, the numbers are not approximates unless the word “about,” “substantially,” or “approximately” is recited. Whenever “substantially,” “approximately,” “about,” or similar language is explicitly used in combination with a specific value, variations up to and including 10% of that value are intended, unless explicitly stated otherwise.

[0033] Directions and other relative references may be used to facilitate discussion of the drawings and principles herein but are not intended to be limiting. For example, certain terms may be used such as “inner,” “outer,” “upper,” “lower,” “top,” “bottom,” “interior,” “exterior,” “left,” right,” “front,” “back,” “rear,” and the like. Such terms are used, where applicable, to provide some clarity of description when dealing with relative relationships, particularly with respect to the illustrated aspects. Such terms are not, however, intended to imply absolute relationships, positions, and / or orientations. For example, with respect to an object, an “upper” part can become a “lower” part simply by turning the object over. Nevertheless, it is still the same part, and the object remains the same.

[0034] As used herein, “comprising” means “including,” and the singular forms “a” or “an” or “the” include plural references unless the context clearly dictates otherwise. The term “or” refers to a single element of stated alternative elements or a combination of two or more elements unless the context clearly indicates otherwise.

[0035] Although there are alternatives for various components, parameters, operating conditions, etc. set forth herein, that does not mean that those alternatives are necessarily equivalent and / or perform equally well. Nor does it mean that the alternatives are listed in a preferred order, unless stated otherwise. Unless stated otherwise, any of the groups defined below can be substituted or unsubstituted.

[0036] Unless explained otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one skilled in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, suitable methods and materials are described below. The materials, methods, and examples are illustrative only and not intended to be limiting. Features of the presently disclosed subject matter will be apparent from the following detailed description and the appended claims.

[0037] Overview of Terms

[0038] The following are provided to facilitate the description of various aspects of the disclosed subject matter and to guide those skilled in the art in the practice of the disclosed subject matter.

[0039] Thermal shock'. Application of a thermal shock temperature for a time period having a duration less than or equal to about 5 minutes. In some embodiments, the duration of the time period of thermal shock temperature application is less or equal to 60 seconds, for example, less than or equal to 30 seconds. For example, in some embodiments, the duration of the thermal shock can be in a range of about 1 millisecond to about 10 seconds, inclusive, for example, about 1-5 seconds. In some embodiments, the thermal shock may involve heating to the thermal shock temperature at a ramp rate of at least 102K / s (e.g., > 103K / s, such as 103to 105K / s, inclusive) prior to the heating time period, and / or cooling from the thermal shock temperature at a ramp rate of at least 102K / s (e.g., > 103K / s, such as 103to 105K / s, inclusive).

[0040] Thermal shock temperature: A peak or maximum temperature at a surface of a heating chamber of a furnace, within an interior volume of the furnace, and / or at a surface of a material being heated (e.g., the substrate and / or precursor(s) thereon). In some embodiments, the thermal shock temperature is at least about 1000 K, for example, in a range of about 1200 K to about 3000 K, inclusive (e.g., 1300-2000 K, inclusive). In some embodiments, a temperature at a material being heated (e.g., precursors on a substrate) within the furnace can match or substantially match (e.g., within 10%) the temperature of the heating chamber or interior volume. Particle size: A maximum cross-sectional dimension (e.g., diameter) of one or more particles. In some embodiments, an identified particle size represents an average particle size for all particles (e.g., an average of the maximum cross-sectional dimensions). In some embodiments, the particle size can be measured according to one or more known standards, such as, but not limited to, ASTM B214-16 entitled “Standard Test Method for Sieve Analysis of Metal Powders,” ASTM B330-20 entitled “Standard Test Methods for Estimating Average Particle Size of Metal Powders and Related Compounds Using Air Permeability,” ASTM B822-20 entitled “Standard Test Method for Particle Size Distribution of Metal Powders and Related Compounds by Light Scattering,” and ASTM B922-20 entitled “Standard Test Method for Metal Powder Specific Surface Area by Physical Adsorption,” all of which are incorporated by reference herein.

[0041] Nanoparticle'. An engineered particle formed of a plurality of elements (e.g., at least two (2) elements, at least four (4) elements, at least five (5) elements, or at least eight (8) elements) and having a maximum cross-sectional dimension (e.g., diameter when the particle is spherical) less than or equal to about 1 pm, for example, about 100 nm or less. In some embodiments, each nanoparticle has a maximum cross-sectional dimension of less than or equal to about 50 nm, for example, in a range of 1-30 nm, inclusive.

[0042] High-Entropy Alloy (HEA) nanoparticle'. A nanoparticle comprising a homogeneous mixture of at least four elements that form a single -phase solid solution.

[0043] Introduction

[0044] Disclosed herein are furnace-based thermal-shock systems and methods, for example, for synthesizing materials (e.g., multi-element nanoparticles, in particular, HEA nanoparticles) on tunable substrates (e.g., distributed metal-based catalysts over solid extrudates such as, but not limited to, carbon, alumina, titania, ceria, zeolite, spinel, perovskite, and silica). The present inventors have found that such nanoparticles can unexpectedly be generated on diverse substrates (e.g., non-carbon) by simply providing a heating support material (e.g., a separate paper, film, mesh, layer, coating, etc.) between a thermally-insulating conveyance member and the precursor- loaded substrate. A thermal shock can then be provided by moving the assembly (e.g., stack of the substrate, heating support material, and conveyance member) into a heating zone of a furnace, where the assembly is exposed to a high temperature (e.g., > 1000 K, such as at least 1200 K) for a short duration (e.g., < 60 seconds). To terminate the exposure (and thus conclude the thermal shock duration), the assembly can be moved out of the heating zone (e.g., out of the furnace). In contrast, when the heating support material was not provided (e.g., when the substrate is supported directly on the thermally-insulating conveyance member), exposure of the substrate and conveyance member to the same high temperature for the same short duration in the heating zone of the furnace was insufficient to generate the desired multi-element nanoparticles, for example, due to ineffective heating and / or non-uniform heating.

[0045] Although the discussion above and elsewhere herein focus on forming HEA nanoparticles, embodiments of the disclosed subject matter are not limited thereto. Rather, other nanoparticles or other materials can be formed using the disclosed thermal shock synthesis systems and methods by appropriate selection of precursors, thermal shock temperature and / or duration, atmospheric conditions, and / or substrate composition. In some embodiments, the disclosed thermal shock synthesis systems and methods can be used to form nanoparticles having multiple elements (e.g., HEA nanoparticles or other high entropy materials, such as but not limited to high-entropy oxides, high-entropy intermetallic s, high-entropy phosphates, etc.). In some embodiments, the disclosed thermal shock synthesis systems and methods can be used to form single element nanoparticles (e.g., metal nanoparticles). In some embodiments, the disclosed thermal shock synthesis systems and methods can be used to process powders, for example, to form a sintered material or layer. Such powders can include, but are not limited to, powder-type catalysts (e.g., free-standing catalysts, carbon-supported catalysts, oxide-supported catalysts, metal-supported catalysts, etc.), single element (e.g., unary) compositions, bi-elemental compositions, and multi-elemental compositions. Alternatively or additionally, in some embodiments, the disclosed thermal shock synthesis systems and methods can be used to apply a surface treatment (e.g., surface-coated cathode and anode materials, such as for a battery) or to otherwise process a material, such as but not limited to cathode and anode materials (e.g., for a battery), solid-state electrolyte materials (e.g., for a battery), and recycled cathode and anode materials (e.g., for a battery).

[0046] Referring to FIG. 1, a configuration 100 of an assembly comprising a substrate 106, a heating support material 108, and a conveyance member 110 within the heating zone of a furnace (e.g., tube furnace or plate furnace) is shown. The furnace can have one or more heating elements that expose the assembly to a thermal shock temperature via radiative heating 104. Although only a single planar heating element 102 is shown in the example of FIG. 1, embodiments of the disclosed subject matter are not limited thereto. Rather, multiple heating elements and / or different shapes / configurations of heating elements are also possible according to one or more contemplated embodiments. In some embodiments, the substrate 106 (e.g., having a cross- sectional dimension, tE, less than or equal to 10 mm) can be a non-conductive solid metal oxide or can have an outermost non-conductive metal oxide layer. For example, the metal oxide can be aluminum oxide (AI2O3), zirconia (ZrO2), titanium oxide (TiO2), cerium oxide (CeO2), silicon oxide (SiO2), magnesium oxide (MgO), zeolite, spinel (MgAhO4), and / or perovskite. In some embodiments, the conveyance member 110 can be used to move the substrate 106 into, out of, and / or through a heating zone of the furnace. In some embodiments, the conveyance member 110, or at least a portion thereof, can be formed of a thermally-insulating material (e.g., a ceramic, such as but not limited to AI2O3 or ZrCh). For example, the conveyance member 110 can be a ceramic boat (e.g., having a length of 5-40 cm, a width of 1-7 cm, and a height of 1-7 cm). In some embodiments, the heating support material 108 can be provided over (e.g., placed on, adhered to, integrally formed on, or deposited on) an upper surface of the conveyance member 110, and the substrate 106 can be supported on an upper surface of the heating support material 108. The substrate 106 can thus be separated from the conveyance member 110 by the heating support material 108.

[0047] In some embodiments, the heating support material 108 (e.g., having a length of 5-40 cm, a width of 1-7 cm, and a thickness, tnsM, of 0.1 mm to 5 cm) can be formed of a refractive material (e.g., having a melting temperature greater than 1000 K). For example, in some embodiments, the heating support material 108 can comprise and / or be formed of carbon (e.g., consisting essentially of carbon). Alternatively, in some embodiments, the heating support material 108 can comprise and / or be formed of one or more ceramics (e.g., AI2O3, SiCh, and / or ZrCh). In some embodiments, the heating support material 108 can have a porous structure, for example, formed by a plurality of fibers (e.g., carbon and / or ceramic fibers). For example, each fiber can have a diameter less than or equal to 50 pm (e.g., in a range of 1-10 pm, inclusive), and the heating support material 108 can be in the form of a felt (e.g., comprising non-woven fibers in a relatively thick layer), paper (e.g., comprising non-woven fibers in a relatively thin layer), cloth (e.g., comprising woven fibers), film (e.g., random arrangement of fibers in a thin layer), or any other porous structure. Alternatively, the heating support material 108 can be a porous and / or low-density layer (e.g., a film formed of carbon black particles) formed or deposited on the conveyance member 110.

[0048] In some embodiments, an area of the heating support material 108 in plan view can be greater than an area of the substrate 106 in plan view. Alternatively or additionally, a thermal conductivity of the heating support material 108 can be greater than that of the conveyance member 110, the substrate 106, or both the conveyance member and the substrate. Alternatively or additionally, an emissivity of the heating support material 108 can be greater than that of the conveyance member 110, the substrate 106, and / or both the conveyance member and the substrate. Alternatively or additionally, a heat capacity of the heating support material 108 can be less than that of the conveyance member 110, the substrate 106, and / or both the conveyance member and the substrate. For example, the heating support material 108 can have (a) a thickness in a range of 100 pm to 5 cm, inclusive; (b) a density less than or equal to 250 kg / m3(e.g., < 150 kg / m3); (c) a thermal conductivity in a range of 0.05-0.5 W / m-K, inclusive; (d) an emissivity of at least 0.8 (e.g., > 0.9, such as -0.99); (e) a specific heat less than or equal to 2 J / g-K (e.g., 0.2-1.75 J / g-K); and / or a porosity of at least 40%.

[0049] In some embodiments, the porosity of the heating support material can be characterized by optical microscopy, electron microscopy (e.g., scanning electron microscopy), or X-ray micro- computed-tomography (micro-CT) imaging (e.g., American Society for Testing and Materials (ASTM) F2450-18, Standard Guide for Assessing Microstructure of Polymeric Scaffolds for Use in Tissue-Engineered Medical Products, ASTM International, West Conshohocken, PA, 2018, which is incorporated herein by reference). Alternatively or additionally, in some embodiments, the porosity of the heating support material can be characterized by performing one or more porometry or porosimetry tests on the heating element. For example, the porosity can be characterized by capillary flow porometry, bubble point testing (e.g., ASTM F316-03(2019) Standard Test Methods for Pore Size Characteristics of Membrane Filters by Bubble Point and Mean Flow Pore Test, ASTM International, West Conshohocken, PA, 2019, which is incorporated herein by reference), or mercury intrusion porosimetry (e.g., UOP578-11, Automated Pore Volume and Pore Size Distribution of Porous Substances by Mercury Porosimetry, ASTM International, West Conshohocken, PA, 2011, or U.S. Pharmacopeial Convention for Micromeritics and Particulate Systems Instruments <267>, Porosimetry by Mercury Intrusion, U.S. Pharmacopeial Convention, which is incorporated herein by reference).

[0050] Without being bound by a particular theory, it is believed that the heating support material 108 can be heated first by the radiative heating 104 (e.g., due to the low specific heat of the heating support material 108) when the assembly is inserted into the heating zone of the furnace. The heating can rapidly spread through the heating support material 108 (e.g., due to its thermal conductivity) to where the substrate 106 contacts the heating support material 108, thereby quickly heating the substrate 106 to the thermal shock temperature via conductive heating 112. Meanwhile, because the conveyance member 110 has a larger size than the substrate 106, a higher heat capacity than the heating support material 108, and / or a lower thermal conductivity than the heating support material 108, the conveyance member 110 may be minimally heated (e.g., to a temperature less than 400 K) during the short duration of the thermal shock. Alternatively or additionally, in some embodiments, the heating support material 108 can at least partially thermally isolate substrate 106 from conveyance member 110, such that the radiative heating 104 can rapidly increase the temperature of the substrate to the thermal shock temperature while conveyance member 110 experiences minimal temperature increase by radiative heating 104. In some embodiments, prior to the thermal shock, the substrate 106 can be loaded with one or more precursors (e.g., metal salts). In some embodiments, after the thermal shock, at least some (e.g., substantially all) of the one or more precursors can be converted to multi-element nanoparticles, such as HEA nanoparticles. In some embodiments, a catalytic structure comprising a plurality of HEA nanoparticles on a substrate can have a low noble metal content, for example, less than or equal to 30 wt% of the catalytic structure (e.g., in a range of 0.1-10 wt%, such as 2-10 wt%). In some embodiments, each nanoparticle can be formed of a plurality of elements, for example, four or more different elemental atoms, in a single particle having a maximum cross-sectional dimension (e.g., diameter), D, less than or equal to 1 pm, for example, in a range of 1-60 nm, inclusive. In some embodiments, multiple nanoparticles can be formed on the same substrate from the thermal shock, with each nanoparticle having a diameter within a narrow Gaussian distribution of nanoparticle diameters on the substrate (e.g., within 5 nm of the average diameter of nanoparticles formed on the substrate). The atoms in the nanoparticle can form a homogeneous mixture as a single-phase solid solution (e.g., having a face-centered cubic (FCC) phase). In some embodiments, the atoms for the nanoparticle are selected from noble metals, transition metals, and lanthanides. Alternatively or additionally, the atoms for the nanoparticle can be selected from actinoids and post-transition metals. Alternatively, in some embodiments, the precursors can be converted or processed by the thermal shock into materials other than HEA nanoparticles, such as but not limited to non-HEA nanoparticles, powders, layers, and materials.

[0051] In FIG. 1, the substrate 106 is shown as a rectangular prism for convenient illustration. However, in practical implementations, the substrate can have a shape different than that illustrated in FIG. 1. In some embodiments, the substrate can be an extruded metal oxide support having any shape, such as, but not limited to an irregular granule, sphere, hollow ring, cube, rectangular prism, cylinder, bilobed, trilobed, or quadrilobed. For example, in some embodiments, the substrate can be an aluminum-based extrudate pellet, such as that disclosed in European Patent No. 0455307 Bl, issued August 10, 1994 and entitled “Process for the preparation of aluminabased extrudates,” or U.S. Patent No. 6,656,875 Bl, issued December 2, 2003, and entitled “Alumina extrudates, methods for preparing and use as catalysts supports,” both of which are incorporated herein by reference. For example, in some embodiments, the substrate can be a multilobe cylindrical pellet, such as that disclosed in U.S. Patent No. 4,028,227 A, issued June 7, 1977, and entitled “Hydrotreating of petroleum residuum using shaped catalyst particles of small diameter pores,” which is incorporated herein by reference. Alternatively or additionally, in some embodiments, the substrate with nanoparticles therein can be ground into a powder, for example, having a particle size less than or equal to 1 mm. In some embodiments, the substrate 106 is an extruded metal oxide support. In some embodiments, the substrate 106 can be a porous structure.

[0052] Furnace-Based System Examples

[0053] Referring to FIG. 2A, a system 200 can have a furnace 202 (e.g., tube furnace, plate furnace, etc.), a control system 204, a conveyance system 206, and a conveyance member 210 (e.g., with the heating support material and one or more substrates thereon). The control system 204 can be operatively coupled to and configured to control operation of the furnace 202 and / or the conveyance system 206. For example, the control system 204 can control furnace 202 (or heating elements thereof) to provide a desired thermal shock temperature at a heating zone 212. Alternatively or additionally, the control system 204 can control conveyance system 206 to move the conveyance member 210 from a loading position 208 (e.g., a first position outside the furnace) to the heating zone 212 (e.g., a second position within the furnace).

[0054] In some embodiments, the furnace 202 can employ one or more Joule heating elements, for example, similar to any of those disclosed in U.S. Publication No. 2018 / 0369771, entitled “Nanoparticles and systems and methods for synthesizing nanoparticles through thermal shock,” U.S. Publication No. 2019 / 0161840, entitled “Thermal shock synthesis of multielement nanoparticles,” International Publication No. WO 2020 / 236767, entitled “High temperature sintering systems and methods,” or International Publication No. WO 2020 / 252435, entitled “Systems and methods for high temperature synthesis of single atom dispersions and multi-atom dispersions,” which heating elements are incorporated herein by reference. Alternatively or additionally, in some embodiments, the furnace 202 can employ microwave heating, laser heating, electron beam heating, spark discharge heating, or any other heating mechanism capable of providing the thermal shock temperature of at least 1000 K via radiative heating. In some embodiments, the furnace is configured as one of a tube furnace and a plate furnace.

[0055] In some embodiments, the duration of the thermal shock may be a product of the length, L, of the heating zone 212 and the velocity, v, of the conveying system 206 (e.g., ti = L / v). The velocity (e.g., 60 inches / minute) of the conveying system 206 can be chosen to achieve a desired time duration of the thermal shock (e.g., < 60 seconds, such as < 10 seconds or even < 5 seconds) and / or a desired heating ramp rate or cooling ramp rate (e.g., > 102K / s). In such a configuration, the heating element(s) of the furnace 202 may be continuously energized, for example, to provide a constant or substantially constant temperature (e.g., > 1000 K, such as > 1200 K) within the heating zone 212. Alternatively or additionally, in some embodiments, the heating element(s) can be operated in a pulsed mode, for example, to provide a time-varying temperature profile in the heating zone 212. In some embodiments, the conveyance system 206 can comprise a robotic arm (e.g., a telescoping arm, etc.), a linear actuator (e.g., screw drive, rack and pinion, hydraulic cylinder, pneumatic cylinder, electromagnetic linear motor, etc.), or other displacement mechanism for moving the conveyance member 210 into and out of the furnace 202. For example, FIG. 2B illustrates operation of a furnace-based system employing a linear actuator as part of the conveyance system. In illustrated example, an assembly 230 comprises a plurality of substrates 228 (with one or more precursors thereon) disposed on heating support material 226, which is in turn disposed on conveyance member 224. In the loading stage 220, a linear actuator (not shown) can move the assembly 230 into the furnace 222. The assembly 230 can be maintained in the furnace 222 and heated thereby during the thermal shock stage 232. After the thermal shock stage 232, the system can proceed to the post-heating stage 234, where the linear actuator can retract to remove the now processed assembly 236 (e.g., with nanoparticle-decorated substrates 238) from the furnace 222.

[0056] Although FIG. 2B shows the assembly being in a same location with respect to the furnace 222 in the loading stage 220 and post-heating stage 234 (e.g., such that the assembly retraces the same path out of the furnace as it did traveling into the furnace), embodiments of the disclosed subject matter are not limited thereto. Rather, in some embodiments, the conveyance system can be configured such that the assembly travels on a different path out of the furnace than it did traveling into the furnace (e.g., traveling on a line, straight or otherwise, through the furnace). Moreover, although the duration of the thermal shock is defined by the assembly 230 moving into and out of the furnace 222, other configurations and operations to achieve a limited duration thermal shock are also possible according to one or more contemplated embodiments. For example, in some embodiments, the assembly 230 can be moved to a position within the furnace 222 but outside the heating zone, such that exposure to the thermal shock temperature is terminated (or the temperature is at least reduced) even though the assembly 230 remains within the furnace 222.

[0057] In the illustrated example of FIG. 2B, the assembly 230 is moved with respect to the furnace 222 by a linear actuator. Alternatively or additionally, the conveyance system 206 can include a conveyor (e.g., comprising a continuous belt, one or more rollers, one or more motors, etc.), for example, supporting the conveyance member 210 thereon such that the conveyance member 210 can be moved into the furnace 202, through the heating zone 212 (e.g., where a transit time through the heating zone defines, at least in part, a duration of the thermal shock), and out of the furnace 202. For example, FIG. 2C illustrates operation of a system employing a conveyor belt 244 as part of the conveyance system. In the illustrated example, an assembly 230 comprises a plurality of substrates 228 (with one or more precursors thereon) disposed on heating support material 226, which is in turn disposed on conveyance member 224 supported by conveyor belt 244. Although illustrated separately in FIG. 2C, in some embodiments, the conveyance member 224 can be integrated with the conveyor belt 244. Alternatively or additionally, in some embodiments, the heating support material 226 can be disposed directly on the conveyor belt 244 (e.g., without an intervening conveyance member 224). In some embodiments, the conveyor belt 244 can be formed of and / or comprise, for example, a woven wire mesh.

[0058] In the loading stage 240, the conveyor belt 244 can move the assembly 230 into the furnace 242. The assembly 230 can traverse the heating zone in the furnace 242 (e.g., where the speed through the heating zone defines, at least in part, the duration of the thermal shock) and heated thereby during the thermal shock stage 246. Alternatively, in some embodiments, the conveyor belt 244 can pause to maintain the assembly 230 within the heating zone of the furnace 242 during the thermal shock stage 246, for example, until a desired duration for the thermal shock is reached. After the thermal shock stage 248, the system can proceed to the post-heating stage 248, where the conveyor belt 244 can move the now processed assembly 236 (e.g., with nanoparticledecorated substrates 238) from the heating zone of the furnace 242. Although FIG. 2C shows the assembly being moved in a straight line by the conveyor belt 244 during the different stages 240, 246, 248, embodiments of the disclosed subject matter are not limited thereto. Rather, other path geometries and / or operations for the conveyor belt 244 are also possible according to one or more contemplated embodiments.

[0059] Although specific furnace configurations are illustrated in FIGS. 2B-2C, embodiments of the disclosed subject matter are not limited thereto. Rather, other furnace configurations are also possible according to one or more contemplated embodiments, such as but not limited to, a pusher furnace (e.g., High Temperature Hybrid Pusher Furnace, manufactured by Abbott Furnace Company of Saint Marys, Pennsylvania, USA) or a continuous belt furnace (e.g., Continuous Belt Sintering Furnace, manufactured by Abbott Furnace Company of Saint Marys, Pennsylvania, USA). For example, FIG. 3 shows a tube furnace system 300 for processing of substrates 306. In the illustrated example, the tube furnace has one or more heating elements 304 in thermal communication with an outer circumference of a cylindrical heating chamber 302, for example, to heat the walls of the heating chamber 302 to provide radiative heating to materials within the chamber 302. For example, the heating chamber 302 can have a diameter, D2, of 7 cm or less, and a length, L4, of 100 cm or less (e.g., about 70 cm).

[0060] Similar to the above-noted examples, an assembly 312 for processing of substrates 306 can include a conveyance member 310 (e.g., ceramic boat) and a heating support material 308. For example, each substrate 306 can have a diameter, DI, of 1-10 mm, inclusive, and a length, LI, of 1-10 mm, inclusive. For example, the heating support material 308 can have a thickness, T2, of 100 pm to 5 cm, inclusive (e.g., 200 pm to 5 mm, inclusive), a width, W2, of 1-7 cm, inclusive, and a length, L2, of 5-40 cm, inclusive. For example, the conveyance member 310 can have a height, H3, of 1-7 cm, inclusive, a width, W3, of 1-7 cm, inclusive, and a length, L3, of 5- 40 cm, inclusive. Thus, multiple substrates 306 (e.g., as many as 300) may be disposed on the upper surface of the heating support material 308 for simultaneous processing in heating chamber 302. The stack of conveyance member 310, heating support material 308, and substrates 306 can be disposed within the internal volume 314 of the heating chamber 302, for example, such that a top surface of the assembly 312 is separated from a facing portion of the inner surface of the heating chamber 302 by a distance, Hl, of about 3 cm, and a bottom surface of the assembly 312 is separate from the facing portion of the inner surface of the heating chamber by a distance, H2, of about 5 cm.

[0061] In some embodiments, the assembly 312 can be moved into and out of the heating chamber 302 of the tube furnace (e.g., to control a duration of heating). In some embodiments, the tube furnace can be equipped to offer different atmospheric conditions within interior volume 314 (e.g., air, O2, Ar, N2, H Ar, etc.). In some embodiments, the tube furnace system 300 can subject the assembly 312 to the thermal shock, such that the precursors on the substrate 306 are converted into HEA nanoparticles (e.g., HEA-dispersed extrudates) or other products. In some embodiments, the tube-fumace-based shock synthesis technique can synthesize a diverse series of HEA catalysts at a substantial scale (e.g., 1-10 kg / hour).

[0062] Method Examples

[0063] FIG. 4 is a process flow diagram for an exemplary method 400 for furnace-based thermal shock and use of products thereof. The method 400 can initiate at process block 402, where a substrate (or multiple substrates) can be provided with one or more precursors thereon. In some embodiments, the providing of process block 402 can include loading the precursors onto the substrate. For example, the loading can comprise coating, impregnating, and / or infiltrating the precursors onto and / or into the substrate, for example, via a wet impregnation technique (e.g., where the precursor solution volume is greater than the pore volume of the substrate) or a dry impregnation technique (e.g., where the precursor solution volume is less than or equal to the pore volume of the substrate). In some embodiments, the loading can be performed by mixing precursors (e.g., metal salts, such as chloride, nitrate, or alkali) in solution (e.g., organic solvent or water) with the substrates, for example, using a rotary drum mixer. For example, the precursor can have a chemical formula of MCLHy, where M is a metal (e.g., Pt, Pd, Ni, Fe, Co, Au, Cu, Sn, etc.), x is equal to or greater than 1, and y is equal to or greater than 0. Other loading methods are also possible according to one or more contemplated embodiments. For example, the precursor loading can include dip coating, brushing, spraying, printing, rolling, incipient wetness spray impregnation, agitated drying, or any combination of the foregoing. In some embodiments, the providing of process block 402 can also include drying the precursor-loaded substrate, for example, to remove solvent therefrom. In some embodiments, the drying can be controlled to avoid agglomeration, detachment, and / or precipitation of the precursors, for example, to enhance or ensure a uniform precursor distribution. In some embodiments, the substrate can be dried via freeze-drying or critical point drying. Alternatively, in some embodiments, the substrate can be subject to oven drying, for example, at a temperature in a range of 20-120 °C.

[0064] The method 400 can proceed to process block 404, where a heating support material can be provided between the conveyance member and the substrate(s). In some embodiments, the heating support material can be a piece of felt, paper, cloth, or other porous film, for example, formed of carbon, ceramic (e.g., AI2O3, SiCh, and / or ZrC ), or other material with similar density, porosity, thermal conductivity, emissivity, and / or heat capacity. For example, the providing of process block 404 can include disposing (e.g., placing and / or adhering) the heating support material onto the conveyance member, and disposing (e.g., placing and / or adhering) the substrate(s) onto the heating support material. Alternatively or additionally, in some embodiments, the heating support material can be a layer or film on a surface of the conveyance member. The layer or film can be formed of carbon (e.g., carbon black particles), ceramic (e.g., ceramic fibers), or other material with similar density, porosity, thermal conductivity, emissivity, and / or heat capacity. For example, the providing of process block 404 can include providing (e.g., depositing, growing, coating, or otherwise forming) the heating support material on the conveyance member, and disposing (e.g., placing and / or adhering) the substrate(s) on the heating support material.

[0065] The method 400 can proceed to process block 406, where the assembly of conveyance member, heating support material, and substrate(s) with precursors thereon can be subjected to heating to provide the desired thermal shock to the substrate(s). In some embodiments, the thermal shock heating can be achieved by a short-duration high temperature profile, with (i) a rapid heating ramp (e.g., > 102K / s, such as 103-105K / s, inclusive), (ii) a short dwell period (e.g., < 60 seconds, such as 1-5 seconds) at or about thermal shock temperature (e.g., > 1000 K, such as 1200-2000 K), and (iii) a rapid cooling ramp (e.g., > 102K / s, such as 103-105K / s, inclusive). In some embodiments, the thermal shock temperature can be sufficient to melt all of the constituent elements of the precursors and / or induce high temperature uniform mixing, while the rapid cooling can enable crystallization of liquid elements into substantially uniform and homogeneous alloy nanoparticles without being subjected to aggregation, agglomeration, element segregation, or phase separation. For example, in some embodiments, a catalytic structure, which comprises the substrate and HEA nanoparticles (or other high-entropy material particles) thereon, can be produced by the thermal shock process.

[0066] In some embodiments, the temperature profile of the thermal shock can provide a rapid transition to and / or from the thermal shock temperature, for example, from / to a low temperature, such as room temperature (e.g., 20-25 °C) or an elevated ambient temperature (e.g., 100-200 °C)). In some embodiments, the heating of the thermal shock process can be provided by Joule heating, microwave heating, laser heating, electron beam heating, spark discharge heating, or any other heating mechanism capable of providing the desired heating rate and temperatures. In some embodiments, the thermal shock can be terminated by conveying the substrates out of a heating zone and / or by de-activating, de-energizing, or otherwise terminating operation of the heating elements. Alternatively or additionally, in some embodiments, the cooling can be achieved using one or more passive cooling features (e.g., heat sinks thermally coupled to the heating element and / or substrate, etc.), one or more active cooling features (e.g., fluid flow directed at the substrate and / or the heater, fluid flow through the substrate or a heat sink thermally coupled thereto, etc.), or any combination thereof.

[0067] The method 400 can proceed to process block 408, where the substrate(s), with products (e.g., nanoparticles) now formed thereon, can be removed from the heating support material and / or the conveyance member. In some embodiments, process block 408 can include removing the assembly of substrate, heating support material, and conveyance member from the furnace, or at least a heating zone thereof, for example, using a conveyance system to move the conveyance member from the heating zone to an unloading position (e.g., outside the furnace).

[0068] The method 400 can proceed to process block 410, where the substrate(s) with products (e.g., nanoparticles, sintered layer, etc.) thereon can be used (e.g., as a catalytic structure, electrolyte, electrode, etc.) or otherwise adapted for subsequent use. In some embodiments, the substrate(s) can be subjected to crushing and / or grinding, for example, to transform the substrate(s) from a bulk material into a powder (e.g., having a particle size < 1 mm). Alternatively or additionally, the substrate, or multiple substrates, can be assembled together in an appropriate holding structure (e.g., an array of Raschig ring) for installation in a reactor. In some embodiments, the substrate(s) can be used in a thermochemical or thermocatalytic reaction.

[0069] For example, the catalytic structure can be employed in the chemical reaction by contacting reactants (e.g., gases) with the HEA nanoparticles of the substrate. In some embodiments, the chemical reaction can be ammonia synthesis, ammonia oxidation, ammonia decomposition, or NOXreduction (e.g., de-NOx). In some embodiments, the substrate of the catalytic structure is porous, and the contacting can comprise flowing reactants through the porous substrate. Alternatively or additionally, in some embodiments, the contacting can comprise flowing reactants parallel to a surface of the substrate upon which the HEA nanoparticles are formed. In some embodiments, the catalytic structure, the reactants, and / or an environment containing the catalytic structure and the reactants can be subject to heating, for example, to provide energy to initiate and / or drive the chemical reaction. For example, the heating may be such that the reactants and / or HEA nanoparticles are subjected to (or maintained at) a peak temperature of 50-900 °C (e.g., 300-600 °C), such as -500 °C. For example, the reactants can be ammonia, and the products can be hydrogen and nitrogen for a thermochemical reaction involving ammonia decomposition, or vice versa for a thermochemical reaction involving ammonia synthesis.

[0070] Although blocks 402-410 of method 400 have been described as being performed once, in some embodiments, multiple repetitions of a particular process block may be employed before proceeding to the next decision block or process block. In addition, although blocks 402-410 of method 400 have been separately illustrated and described, in some embodiments, process blocks may be combined and performed together (simultaneously or sequentially). Moreover, although FIG. 4 illustrates a particular order for blocks 402-410, embodiments of the disclosed subject matter are not limited thereto. Indeed, in certain embodiments, the blocks may occur in a different order than illustrated or simultaneously with other blocks. In some embodiments, method 400 can include steps or other aspects not specifically illustrated in FIG. 4. Alternatively or additionally, in some embodiments, method 400 may comprise only some of blocks 402-410 of FIG. 4.

[0071] Computer Implementation Examples

[0072] FIG. 5 depicts a generalized example of a suitable computing environment 531 in which the described innovations may be implemented, such as but not limited to control system 204, a controller of a furnace (e.g., any of 222, 242, and 300), and / or method 400. The computing environment 531 is not intended to suggest any limitation as to scope of use or functionality, as the innovations may be implemented in diverse general-purpose or special-purpose computing systems. For example, the computing environment 531 can be any of a variety of computing devices (e.g., desktop computer, laptop computer, server computer, tablet computer, etc.).

[0073] With reference to FIG. 5, the computing environment 531 includes one or more processing units 535, 537 and memory 539, 541. In FIG. 5, this basic configuration 551 is included within a dashed line. The processing units 535, 537 execute computer-executable instructions. A processing unit can be a central processing unit (CPU), processor in an application-specific integrated circuit (ASIC), or any other type of processor (e.g., hardware processors, graphics processing units (GPUs), virtual processors, etc.). In a multi-processing system, multiple processing units execute computer-executable instructions to increase processing power. For example, FIG. 5 shows a central processing unit 535 as well as a graphics processing unit or coprocessing unit 537. The tangible memory 539, 541 may be volatile memory (e.g., registers, cache, RAM), non-volatile memory (e.g., ROM, EEPROM, flash memory, etc.), or some combination of the two, accessible by the processing unit(s). The memory 539, 541 stores software 533 implementing one or more innovations described herein, in the form of computer-executable instructions suitable for execution by the processing unit(s).

[0074] A computing system may have additional features. For example, the computing environment 531 includes storage 561, one or more input devices 571, one or more output devices 581, and one or more communication connections 591. An interconnection mechanism (not shown) such as a bus, controller, or network interconnects the components of the computing environment 531. Typically, operating system software (not shown) provides an operating environment for other software executing in the computing environment 531, and coordinates activities of the components of the computing environment 531.

[0075] The tangible storage 561 may be removable or non-removable, and includes magnetic disks, magnetic tapes or cassettes, CD-ROMs, DVDs, or any other medium which can be used to store information in a non-transitory way, and which can be accessed within the computing environment 531. The storage 561 can store instructions for the software 533 implementing one or more innovations described herein.

[0076] The input device(s) 571 may be a touch input device such as a keyboard, mouse, pen, or trackball, a voice input device, a scanning device, or another device that provides input to the computing environment 531. The output device(s) 581 may be a display, printer, speaker, CD- writer, or another device that provides output from computing environment 531.

[0077] The communication connection(s) 591 enable communication over a communication medium to another computing entity. The communication medium conveys information such as computer-executable instructions, audio or video input or output, or other data in a modulated data signal. A modulated data signal is a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media can use an electrical, optical, radio-frequency (RF), or another carrier.

[0078] Any of the disclosed methods can be implemented as computer-executable instructions stored on one or more computer-readable storage media (e.g., one or more optical media discs, volatile memory components (such as DRAM or SRAM), or non-volatile memory components (such as flash memory or hard drives)) and executed on a computer (e.g., any commercially available computer, including smart phones or other mobile devices that include computing hardware). The term computer-readable storage media does not include communication connections, such as signals and carrier waves. Any of the computer-executable instructions for implementing the disclosed techniques as well as any data created and used during implementation of the disclosed embodiments can be stored on one or more computer-readable storage media. The computer-executable instructions can be part of, for example, a dedicated software application or a software application that is accessed or downloaded via a web browser or other software application (such as a remote computing application). Such software can be executed, for example, on a single local computer (e.g., any suitable commercially available computer) or in a network environment (e.g., via the Internet, a wide-area network, a local-area network, a client-server network (such as a cloud computing network), or any other such network) using one or more network computers.

[0079] For clarity, only certain selected aspects of the software-based implementations are described. Other details that are well known in the art are omitted. For example, it should be understood that the disclosed technology is not limited to any specific computer language or program. For instance, aspects of the disclosed technology can be implemented by software written in C++, Java™, Python®, and / or any other suitable computer language. Likewise, the disclosed technology is not limited to any particular computer or type of hardware. Certain details of suitable computers and hardware are well known and need not be set forth in detail in this disclosure.

[0080] It should also be well understood that any functionality described herein can be performed, at least in part, by one or more hardware logic components, instead of software. For example, and without limitation, illustrative types of hardware logic components that can be used include Field- programmable Gate Arrays (FPGAs), Program- specific Integrated Circuits (ASICs), Programspecific Standard Products (ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), etc.

[0081] Furthermore, any of the software-based embodiments (comprising, for example, computer-executable instructions for causing a computer to perform any of the disclosed methods) can be uploaded, downloaded, or remotely accessed through a suitable communication means. Such suitable communication means include, for example, the Internet, the World Wide Web, an intranet, software applications, cable (including fiber optic cable), magnetic communications, electromagnetic communications (including RF, microwave, and infrared communications), electronic communications, or other such communication means. In any of the above-described examples and embodiments, provision of a request (e.g., data request), indication (e.g., data signal), instruction (e.g., control signal), or any other communication between systems, components, devices, etc. can be by generation and transmission of an appropriate electrical signal by wired or wireless connections.

[0082] Fabricated. Examples and. Experimental Results

[0083] A tube-furnace (length: 70 cm, diameter: 5 cm), similar to the configuration of FIG. 3, was used to heat AI2O3 extrudates with precursors thereon, and thus produce AI2O3- supported HEA (PtPdRhCoCe) catalysts. Carbon felt (length: 7 cm, width: 3.5 cm, thickness: 2 mm) was used as a heating support material, in particular, to cover an AI2O3 ceramic boat (length: 8 cm, width: 4 cm, height: 2 cm), which held the precursor-loaded AI2O3 extrudates. This arrangement was then inserted into the heated zone of the argon-filled tube furnace. The heating temperature and duration were controlled. Upon removing the boat, the AhCF-supported HEA catalysts were procured. The HEA nanoparticles were synthesized at temperatures between 1473-1773 K, for a duration of 2 seconds. As shown in Table 1, the sample synthesized at the lowest temperature (1473 K) for 2 seconds displayed incomplete sintering. However, other samples synthesized under varying conditions demonstrated excellent elemental mixing.

[0084] Table 1: Composition of HEA-dispersed AI2O3 extrudates and their synthesis conditions using furnace heating

[0085] The tube-furnace (length: 70 cm, diameter: 5 cm) was further used to heat AI2O3 extrudates with precursors thereon, and thus produce additional AI2O3- supported HEA (PtPdRhCoCe) catalysts. In particular, the heating temperature was 1100 °C (1373 K) for a duration of 4 seconds via radiative heating. Various setups (e.g., for heating support material and / or the conveyance member) were used to hold the precursor-loaded AI2O3 extrudates. The assembly of substrate, heating support material, and conveyance member was then inserted into the core of the argon- filled tube furnace. Upon removing the assembly, AI2O3- supported HEA catalysts were produced in some cases, in particular, depending on the heating support material used, as shown in Table 2. In particular and unexpectedly, when porous carbon (e.g., carbon felt, carbon paper, uniform coating of carbon black particles, etc.) or porous ceramic (e.g., ceramic fiber paper, ceramic fiber log, ceramic fiber blanket) was used as the heating support material, nanoparticles were formed on the extrudate when exposed to the thermal shock. In contrast, when no heating support material was used or when other materials (e.g., dense graphite, porous metal, etc.) were used as the heating support material, the resulting particles displayed noticeable color differences (e.g., shades of black and blue) indicative of uneven distribution of temperature and / or insufficient heating provided by the thermal shock.

[0086] Table 2: Experimental results with variations in heating support material, substrate, and conveyance member. Additional Examples of the Disclosed Technology

[0087] In view of the above-described implementations of the disclosed subject matter, this application discloses the additional examples in the clauses enumerated below. It should be noted that one feature of a clause in isolation, or more than one feature of the clause taken in combination, and, optionally, in combination with one or more features of one or more further clauses are further examples also falling within the disclosure of this application.

[0088] Clause 1. An assembly for use with a furnace, the assembly comprising: a substrate having one or more precursors thereon; a conveyance member constructed such that at least a first portion of the conveyance member is movable between first and second positions with respect to the furnace; and a heating support material arranged between the first portion of the conveyance member and the substrate, and supporting the substrate on the first portion of the conveyance member.

[0089] Clause 2. The assembly of any clause or example herein, in particular, Clause 1, wherein the conveyance member comprises a ceramic boat.

[0090] Clause 3. The assembly of any clause or example herein, in particular, Clause 2, wherein the ceramic boat comprises and / or is formed of AI2O3 or ZrCh.

[0091] Clause 4. The assembly of any clause or example herein, in particular, any one of Clauses 1- 3, wherein the substrate comprises an extrudate.

[0092] Clause 5. The assembly of any clause or example herein, in particular, Clause 4, wherein the extrudate comprises and / or is formed of AI2O3, Z1O2, TiCh, SiC , MgO, or MgAhCU.

[0093] Clause 6. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0094] 5, wherein the one or more precursors comprise and / or are formed of a metal salt.

[0095] Clause 7. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0096] 6, wherein the heating support material is composed of carbon.

[0097] Clause 8. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0098] 7, wherein the heating support material is formed of and / or comprises carbon fibers having a diameter of 50 pm or less.

[0099] Clause 9. The assembly of any clause or example herein, in particular, Clause 8, wherein each carbon fiber has a diameter in a range of 1-10 pm, inclusive. Clause 10. The assembly of any clause or example herein, in particular, any one of Clauses 8- 9, wherein the heating support material comprises a felt, paper, cloth, or film formed by the carbon fibers.

[0100] Clause 11. The assembly of any clause or example herein, in particular, any one of Clauses 1- 6, wherein the heating support material is composed of one or more ceramics.

[0101] Clause 12. The assembly of any clause or example herein, in particular, Clause 11, wherein the heating support material is composed of AI2O3, SiCh, Z1O2. C Oa, or any combination of the foregoing.

[0102] Clause 13. The assembly of any clause or example herein, in particular, any one of Clauses 11-12, wherein the heating support material comprises ceramic fibers having a diameter of 50 pm or less.

[0103] Clause 14. The assembly of any clause or example herein, in particular, Clause 13, wherein each ceramic fiber has a diameter in a range of 1-10 pm, inclusive.

[0104] Clause 15. The assembly of any clause or example herein, in particular, any one of Clauses 13-14, wherein the heating support material comprises a felt, paper, cloth, or film formed by the ceramic fibers.

[0105] Clause 16. The assembly of any clause or example herein, in particular, any one of Clauses 1- 6, wherein the heating support material comprises a layer formed or deposited on at least the first portion of the conveyance member.

[0106] Clause 17. The assembly of any clause or example herein, in particular, Clause 16, wherein the layer is formed of carbon.

[0107] Clause 18. The assembly of any clause or example herein, in particular, any one of Clauses 16-17, wherein the layer consists essentially of carbon.

[0108] Clause 19. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0109] 18, wherein the heating support material has a thickness in a range of 10 pm to 10 mm, inclusive.

[0110] Clause 20. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0111] 19, wherein a thickness of the heating support material is in a range of 200 pm to 5 mm, inclusive.

[0112] Clause 21. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0113] 20, wherein the heating support material is formed as a separate structure placed on and in contact with a surface of the first portion of the conveyance member. Clause 22. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0114] 21, wherein an area of the heating support material in plan view is greater than an area of the substrate in plan view.

[0115] Clause 23. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0116] 22, wherein a thermal conductivity of the heating support material is greater than that of the conveyance member, the substrate, or both the conveyance member and the substrate.

[0117] Clause 24. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0118] 23, wherein an emissivity of the heating support material is greater than that of the conveyance member, the substrate, and / or both the conveyance member and the substrate.

[0119] Clause 25. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0120] 24, wherein a heat capacity and / or specific heat of the heating support material is less than that of the conveyance member, the substrate, and / or both the conveyance member and the substrate.

[0121] Clause 26. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0122] 25, wherein a density of the heating support material is less than or equal to 250 kg / m3.

[0123] Clause 27. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0124] 26, wherein a density of the heating support material is less than or equal to 150 kg / m3.

[0125] Clause 28. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0126] 27, wherein a thermal conductivity of the heating support material along a thickness direction thereof is in a range of 0.05 W / m-K to 0.5 W / m-K, inclusive.

[0127] Clause 29. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0128] 28, wherein an emissivity of the heating support material is at least 0.8.

[0129] Clause 30. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0130] 29, wherein an emissivity of the heating support material is at least 0.9, for example, about 0.99.

[0131] Clause 31. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0132] 30, wherein a specific heat of the heating support material is less than or equal to 2 J / g-K.

[0133] Clause 32. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0134] 31, wherein a specific heat of the heating support material is in a range of 0.2 J / g-K to 1.75 J / g-K, inclusive.

[0135] Clause 33. The assembly of any clause or example herein, in particular, any one of Clauses 1-

[0136] 32, wherein the heating support material has a porosity of at least 40%. Clause 34. A system comprising a furnace and the assembly of any clause or example herein, in particular, any one of Clauses 1-33.

[0137] Clause 35. The system of any clause or example herein, in particular, Clause 34, wherein the furnace comprises a heating chamber and one or more heating elements.

[0138] Clause 36. The system of any clause or example herein, in particular, Clause 35, wherein the heating chamber is formed of and / or comprises a ceramic.

[0139] Clause 37. The system of any clause or example herein, in particular, any one of Clauses 34- 36, further comprising a control system operatively coupled to the furnace and configured to control operation thereof, the control system comprising one or more processors and one or more computer-readable storage media storing instructions that, when executed by the one or more processors, control the furnace to subject the substrate to a thermal shock, wherein the thermal shock comprises exposing the substrate to a temperature of at least 1000 K for a duration of 60 seconds or less.

[0140] Clause 38. The system of any clause or example herein, in particular, Clause 37, wherein the thermal shock is effective to convert the one or more precursors into a plurality of multi-element nanoparticles on the substrate.

[0141] Clause 39. The system of any clause or example herein, in particular, Clause 37, wherein the thermal shock is effective to convert the one or more precursors into one or more sintered structures.

[0142] Clause 40. The system of any clause or example herein, in particular, any one of Clauses 34- 39, further comprising: a conveyance system configured to move the first portion of the conveyance member between the first and second positions; and a control system operatively coupled to the furnace and the conveyance system and configured to control operations thereof, the control system comprising one or more processors and one or more computer-readable storage media storing instructions that, when executed by the one or more processors, control at least the conveyance system to subject the substrate to a thermal shock, wherein the thermal shock comprises exposing the substrate to a temperature of at least 1000 K for a duration of 60 seconds or less.

[0143] Clause 41. The system of any clause or example herein, in particular, any one of Clause 40, wherein the one or more computer-readable storage media store additional instructions that, when executed by the one or more processors, further cause the control system to control the duration of the thermal shock by moving, via the conveyance system, the first portion of the conveyance member into, within, and / or out of the furnace.

[0144] Clause 42. The system of any clause or example herein, in particular, any one of Clauses 40- 41, wherein the thermal shock is effective to convert the one or more precursors into a plurality of multi-element nanoparticles on the substrate.

[0145] Clause 43. The system of any clause or example herein, in particular, any one of Clauses 40- 41, wherein the thermal shock is effective to convert the one or more precursors into one or more sintered structures.

[0146] Clause 44. The system of any clause or example herein, in particular, any one of Clauses 34- 43, wherein the furnace is configured as a tube furnace.

[0147] Clause 45. The system of any clause or example herein, in particular, any one of Clauses 34- 43, wherein the furnace is configured as a plate furnace.

[0148] Clause 46. The system of any clause or example herein, in particular, any one of Clauses 34- 45, wherein the conveyance member is movable between the first position, which is outside the furnace, and the second position, which is inside the furnace.

[0149] Clause 47. A method comprising: providing a heating support material on a first portion of a conveyance member, at least the first portion of the conveyance member being movable between first and second positions with respect to a furnace; providing a substrate on the heating support material, such that the heating support material is between the first portion of the conveyance member and the substrate, and such that the heating support material supports the substrate on the first portion of the conveyance member, the substrate having one or more precursors thereon; and subjecting, via the furnace, the one or more precursors on the substrate, the thermal shock comprising a temperature of at least 1000 K for a duration of 60 seconds or less, the substrate being supported on the heating support material and the first portion of the conveyance member during the subjecting.

[0150] Clause 48. The method of any clause or example herein, in particular, Clause 47, wherein the furnace is a tube furnace or a plate furnace.

[0151] Clause 49. The method of any clause or example herein, in particular, any one of Clauses 47- 48, wherein the conveyance member comprises a ceramic boat. Clause 50. The method of any clause or example herein, in particular, any one of Clauses 47-

[0152] 49, wherein at least the first portion of the conveyance member comprises and / or is formed of AI2O3 or ZrO2.

[0153] Clause 51. The method of any clause or example herein, in particular, any one of Clauses 47-

[0154] 50, wherein the substrate comprises an extrudate.

[0155] Clause 52. The method of any clause or example herein, in particular, Clause 51, wherein the extrudate comprises and / or is formed of AI2O3, ZrC , TiCh, SiC , MgO, or MgAhCU.

[0156] Clause 53. The method of any clause or example herein, in particular, any one of Clauses 47-

[0157] 52, wherein the one or more precursors comprise and / or are formed of a metal salt.

[0158] Clause 54. The method of any clause or example herein, in particular, any one of Clauses 47-

[0159] 53, wherein the heating support material is composed of carbon.

[0160] Clause 55. The method of any clause or example herein, in particular, any one of Clauses 47-

[0161] 54, wherein the heating support material comprises carbon fibers having a diameter of 50 pm or less.

[0162] Clause 56. The method of any clause or example herein, in particular, Clause 55, wherein each carbon fiber has a diameter in a range of 1-10 pm, inclusive.

[0163] Clause 57. The method of any clause or example herein, in particular, any one of Clauses 55- 56, wherein the heating support material comprises a felt, paper, cloth, or film formed by the carbon fibers.

[0164] Clause 58. The method of any clause or example herein, in particular, any one of Clauses 47- 53, wherein the heating support material is composed of one or more ceramics.

[0165] Clause 59. The method of any clause or example herein, in particular, Clause 58, wherein the heating support material is composed of AI2O3, SiCh, ZrC , Cr2O3, or any combination of the foregoing.

[0166] Clause 60. The method of any clause or example herein, in particular, any one of Clauses 58- 59, wherein the heating support material comprises ceramic fibers having a diameter of 50 pm or less.

[0167] Clause 61. The method of any clause or example herein, in particular, Clause 60, wherein each ceramic fiber has a diameter in a range of 1-10 pm, inclusive.

[0168] Clause 62. The method of any clause or example herein, in particular, any one of Clauses 60- 61 , wherein the heating support comprises a felt, paper, cloth, or film formed by the ceramic fibers. Clause 63. The method of any clause or example herein, in particular, any one of Clauses 47- 53, wherein the heating support material comprises a layer formed or deposited on at least the first portion of the conveyance member.

[0169] Clause 64. The method of any clause or example herein, in particular, Clause 63, wherein the layer is formed of carbon.

[0170] Clause 65. The method of any clause or example herein, in particular, any one of Clauses 63-

[0171] 64, wherein the layer consists essentially of carbon.

[0172] Clause 66. The method of any clause or example herein, in particular, any one of Clauses 63-

[0173] 65, wherein the providing the heating support material comprises forming or depositing said layer on the first portion of the conveyance member.

[0174] Clause 67. The method of any clause or example herein, in particular, any one of Clauses 47-

[0175] 66, wherein the heating support material has a thickness in a range of 10 pm to 10 mm, inclusive.

[0176] Clause 68. The method of any clause or example herein, in particular, any one of Clauses 47-

[0177] 67, wherein a thickness of the heating support material is in a range of 200 pm to 5 mm, inclusive.

[0178] Clause 69. The method of any clause or example herein, in particular, any one of Clauses 47- 62, wherein the heating support material is a separate structure from the conveyance member, and the providing the heating support material comprises place the heating support material in contact with a surface of the first portion of the conveyance member.

[0179] Clause 70. The method of any clause or example herein, in particular, any one of Clauses 47-

[0180] 69, wherein: an area of the heating support material in plan view is greater than an area of the substrate in plan view; a thermal conductivity of the heating support material is greater than that of the conveyance member, the substrate, or both the conveyance member and the substrate; an emissivity of the heating support material is greater than that of the conveyance member, the substrate, and / or both the conveyance member and the substrate; a heat capacity of the heating support material is less than that of the conveyance member, the substrate, and / or both the conveyance member and the substrate; or any combination of the above.

[0181] Clause 71. The method of any clause or example herein, in particular, any one of Clauses 47-

[0182] 70, wherein: a density of the heating support material is less than or equal to 250 kg / m3; a thermal conductivity of the heating support material along a thickness direction thereof is in a range of 0.05 W / m-K to 0.5 W / m-K, inclusive; an emissivity of the heating support material is at least 0.8; a specific heat of the heating support material is less than or equal to 2 J / g-K; the heating support material has a porosity of at least 40%; or any combination of the above.

[0183] Clause 72. The method of any clause or example herein, in particular, any one of Clauses 47-

[0184] 71, wherein: a density of the heating support material is less than or equal to 150 kg / m3; an emissivity of the heating support material is at least 0.9; a specific heat of the heating support material is in a range of 0.2 J / g-K to 1.75 J / g-K, inclusive; or any combination of the above.

[0185] Clause 73. The method of any clause or example herein, in particular, any one of Clauses 47-

[0186] 72, wherein the duration of the thermal shock is controlled by moving the substrate into, within, and / or out of the furnace via the conveyance member and the heating support material.

[0187] Clause 74. The method of any clause or example herein, in particular, Clause 73, wherein the moving is performed by a conveyance system configured to move the first portion of the conveyance member between the first and second positions.

[0188] Clause 75. The method of any clause or example herein, in particular, any one of Clauses 47- 74, wherein the thermal shock converts the one or more precursors into a plurality of multielement nanoparticles on the substrate.

[0189] Clause 76. The method of any clause or example herein, in particular, Clause 75, wherein each nanoparticle comprises at least four different elements.

[0190] Clause 77. The method of any clause or example herein, in particular, any one of Clauses 47- 74, wherein the thermal shock converts the one or more precursors into one or more sintered structures having a porosity less than that of the one or more precursors and / or a density greater than that of the one or more precursors.

[0191] Clause 78. The method of any clause or example herein, in particular, any one of Clauses 47-

[0192] 77, wherein the first position is outside the furnace, and the second position inside the furnace.

[0193] Clause 79. The method of any clause or example herein, in particular, any one of Clauses 47-

[0194] 78, wherein the furnace comprises a heating chamber and one or more heating elements in thermal communication with the heating chamber, and heating of the one or more precursors to provide the thermal shock is provided, at least in part, by radiative heating from the heating chamber.

[0195] Clause 80. The method of any clause or example herein, in particular, any one of Clauses 47- 79, wherein: prior to and during the subjecting to the thermal shock, a temperature of the furnace (e.g., a heating chamber thereof) is maintained substantially constant; and / or during and after the subjecting to the thermal shock, the temperature of the furnace (e.g., a heating chamber thereof) is maintained substantially constant.

[0196] Conclusion

[0197] Any of the features illustrated or described herein, for example, with respect to FIGS. 1-6 and Clauses 1-80, can be combined with any other feature illustrated or described herein, for example, with respect to FIGS. 1-6 and Clauses 1-80, to provide materials, systems, devices, structures, methods, aspects, or embodiments not otherwise illustrated or specifically described herein. All features described herein are independent of one another and, except where structurally impossible, can be used in combination with any other feature described herein. In view of the many possible aspects to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated features are only examples and should not be taken as limiting the scope of the disclosed technology. Rather, the scope is defined by the following claims. Applicants therefore claim all that comes within the scope and spirit of these claims.

Claims

CLAIMS1. A method comprising: providing a heating support material on a first portion of a conveyance member, at least the first portion of the conveyance member being movable between first and second positions with respect to a furnace; providing a substrate on the heating support material, such that the heating support material is between the first portion of the conveyance member and the substrate, and such that the heating support material supports the substrate on the first portion of the conveyance member, the substrate having one or more precursors thereon; and subjecting, via the furnace, the one or more precursors on the substrate to a thermal shock, the thermal shock comprising a temperature of at least 1000 K for a duration of 60 seconds or less, the substrate being supported on the heating support material and the first portion of the conveyance member during the subjecting.

2. The method of claim 1, wherein the furnace is configured as a tube furnace or a plate furnace.

3. The method of claim 1, wherein the conveyance member comprises a ceramic boat.

4. The method of claim 3, wherein the ceramic boat comprises and / or is formed of AI2O3 or Z1O2.

5. The method of claim 1, wherein the substrate comprises an extrudate.

6. The method of claim 5, wherein the extrudate comprises and / or is formed of AI2O3, ZrO2, TiO2, SiO2, MgO, or MgAhCU.

7. The method of claim 1, wherein the one or more precursors comprise and / or are formed of a metal salt.

8. The method of claim 1, wherein the heating support material is composed of carbon.

9. The method of claim 8, wherein the heating support material comprises carbon fibers having a diameter of 50 pm or less.

10. The method of claim 9, wherein each carbon fiber has a diameter in a range of 1- 10 pm, inclusive.

11. The method of claim 9, wherein the heating support material comprises a felt, paper, cloth, or film formed by the carbon fibers.

12. The method of claim 1, wherein the heating support material is composed of one or more ceramics.

13. The method of claim 12, wherein the heating support material is composed of AI2O3, SiO2, ZrO2, &2O3, or any combination of the foregoing.

14. The method of claim 12, wherein the heating support material comprises ceramic fibers having a diameter of 50 pm or less.

15. The method of claim 14, wherein each ceramic fiber has a diameter in a range of 1-10 pm, inclusive.

16. The method of claim 14, wherein the heating support comprises a felt, paper, cloth, or film formed by the ceramic fibers.

17. The method of claim 1, wherein the heating support material comprises a layer formed or deposited on at least the first portion of the conveyance member.

18. The method of claim 17, wherein the layer is formed of carbon.

19. The method of claim 18, wherein the layer consists essentially of carbon.

20. The method of claim 17, wherein the providing the heating support material comprises forming or depositing said layer on the first portion of the conveyance member.

21. The method of claim 1, wherein the heating support material has a thickness in a range of 10 pm to 10 mm, inclusive.

22. The method of claim 21, wherein the thickness of the heating support material is in a range of 200 pm to 5 mm, inclusive.

23. The method of claim 1, wherein the heating support material is a separate structure from the conveyance member, and the providing the heating support material comprises place the heating support material in contact with a surface of the first portion of the conveyance member.

24. The method of claim 1, wherein: an area of the heating support material in plan view is greater than an area of the substrate in plan view; a thermal conductivity of the heating support material is greater than that of the conveyance member, the substrate, or both the conveyance member and the substrate; an emissivity of the heating support material is greater than that of the conveyance member, the substrate, and / or both the conveyance member and the substrate; a heat capacity of the heating support material is less than that of the conveyance member, the substrate, and / or both the conveyance member and the substrate; or any combination of the above.

25. The method of claim 1, wherein: a density of the heating support material is less than or equal to 250 kg / m3; a thermal conductivity of the heating support material along a thickness direction thereof is in a range of 0.05 W / m-K to 0.5 W / m-K, inclusive; an emissivity of the heating support material is at least 0.8; a specific heat of the heating support material is less than or equal to 2 J / g-K; the heating support material has a porosity of at least 40%; or any combination of the above.

26. The method of claim 25, wherein: the density of the heating support material is less than or equal to 150 kg / m3; the emissivity of the heating support material is at least 0.9;the specific heat of the heating support material is in a range of 0.2 J / g-K to 1.75 J / g-K, inclusive; or any combination of the above.

27. The method of claim 1, wherein the duration of the thermal shock is controlled by moving the substrate into, within, and / or out of the furnace via the conveyance member and the heating support material.

28. The method of claim 27, wherein the moving is performed by a conveyance system configured to move the first portion of the conveyance member between the first and second positions.

29. The method of claim 1, wherein the thermal shock converts the one or more precursors into a plurality of multi-element nanoparticles on the substrate.

30. The method of claim 29, wherein each nanoparticle comprises at least four different elements.

31. The method of claim 1, wherein the thermal shock converts the one or more precursors into one or more sintered structures having a porosity less than that of the one or more precursors and / or a density greater than that of the one or more precursors.

32. The method of claim 1, wherein the first position is outside the furnace, and the second position inside the furnace.

33. The method of claim 1, wherein: the furnace comprises a heating chamber and one or more heating elements in thermal communication with the heating chamber, and heating of the one or more precursors to provide the thermal shock is provided, at least in part, by radiative heating from the heating chamber.

34. The method of claim 33, wherein: prior to and during the subjecting to the thermal shock, a temperature of the heating chamber is maintained substantially constant; and / orduring and after the subjecting to the thermal shock, the temperature of the heating chamber is maintained substantially constant.

35. An assembly for use with a furnace, the assembly comprising: a substrate having one or more precursors thereon; a conveyance member constructed such that at least a first portion of the conveyance member is movable between first and second positions with respect to the furnace; and a heating support material arranged between the first portion of the conveyance member and the substrate, and supporting the substrate on the first portion of the conveyance member.

36. The assembly of claim 35, wherein the conveyance member comprises a ceramic boat.

37. The assembly of claim 36, wherein the ceramic boat comprises and / or is formed of AI2O3 or ZrO2.

38. The assembly of claim 35, wherein the substrate comprises an extrudate.

39. The assembly of claim 38, wherein the extrudate comprises and / or is formed of AI2O3, ZrO2, TiO2, SiO2, MgO, or MgAhCU.

40. The assembly of claim 35, wherein the one or more precursors comprise and / or are formed of a metal salt.

41. The assembly of claim 35, wherein the heating support material is composed of carbon.

42. The assembly of claim 41, wherein the heating support material comprises carbon fibers having a diameter of 50 pm or less.

43. The assembly of claim 42, wherein each carbon fiber has a diameter in a range of 1-10 pm, inclusive.

44. The assembly of claim 42, wherein the heating support material comprises a felt, paper, cloth, or film formed by the carbon fibers.

45. The assembly of claim 35, wherein the heating support material is composed of one or more ceramics.

46. The assembly of claim 45, wherein the heating support material is composed of AI2O3, SiO2, ZrO2, &2O3, or any combination of the foregoing.

47. The assembly of claim 45, wherein the heating support material comprises ceramic fibers having a diameter of 50 pm or less.

48. The assembly of claim 47, wherein each ceramic fiber has a diameter in a range of 1-10 pm, inclusive.

49. The assembly of claim 47, wherein the heating support material comprises a felt, paper, cloth, or film formed by the ceramic fibers.

50. The assembly of claim 35, wherein the heating support material comprises a layer formed or deposited on at least the first portion of the conveyance member.

51. The assembly of claim 50, wherein the layer is formed of carbon.

52. The assembly of claim 51, wherein the layer consists essentially of carbon.

53. The assembly of claim 35, wherein the heating support material has a thickness in a range of 10 pm to 10 mm, inclusive.

54. The assembly of claim 53, wherein the thickness of the heating support material is in a range of 200 pm to 5 mm, inclusive.

55. The assembly of claim 35, wherein the heating support material is formed as a separate structure placed on and in contact with a surface of the first portion of the conveyance member.

56. The assembly of claim 35, wherein an area of the heating support material in plan view is greater than an area of the substrate in plan view.

57. The assembly of claim 35, wherein a thermal conductivity of the heating support material is greater than that of the conveyance member, the substrate, or both the conveyance member and the substrate.

58. The assembly of claim 35, wherein an emissivity of the heating support material is greater than that of the conveyance member, the substrate, and / or both the conveyance member and the substrate.

59. The assembly of claim 35, wherein a heat capacity of the heating support material is less than that of the conveyance member, the substrate, and / or both the conveyance member and the substrate.

60. The assembly of claim 35, wherein a density of the heating support material is less than or equal to 250 kg / m3.

61. The assembly of claim 60, wherein the density of the heating support material is less than or equal to 150 kg / m3.

62. The assembly of claim 35, wherein a thermal conductivity of the heating support material along a thickness direction thereof is in a range of 0.05 W / m-K to 0.5 W / m-K, inclusive.

63. The assembly of claim 35, wherein an emissivity of the heating support material is at least 0.8.

64. The assembly of claim 63, wherein the emissivity of the heating support material is at least 0.9.

65. The assembly of claim 35, wherein a specific heat of the heating support material is less than or equal to 2 J / g-K.

66. The assembly of claim 65, wherein the specific heat of the heating support material is in a range of 0.2 J / g-K to 1.75 J / g-K, inclusive.

67. The assembly of claim 35, wherein the heating support material has a porosity of at least 40%.

68. A system comprising: a furnace; and the assembly of any one of claims 35-67.

69. The system of claim 68, wherein the furnace comprises a heating chamber and one or more heating elements.

70. The system of claim 69, wherein the heating chamber is formed of and / or comprises a ceramic.

71. The system of claim 69, further comprising: a control system operatively coupled to the furnace and configured to control operation thereof, the control system comprising one or more processors and one or more computer- readable storage media storing instructions that, when executed by the one or more processors, control the furnace to subject the substrate to a thermal shock, wherein the thermal shock comprises exposing the substrate to a temperature of at least 1000 K for a duration of 60 seconds or less.

72. The system of claim 71, wherein the thermal shock is effective to convert the one or more precursors into a plurality of multi-element nanoparticles on the substrate.

73. The system of claim 71, wherein the thermal shock is effective to convert the one or more precursors into one or more sintered structures.

74. The system of claim 68, further comprising: a conveyance system configured to move the first portion of the conveyance member between the first and second positions; anda control system operatively coupled to the furnace and the conveyance system and configured to control operations thereof, the control system comprising one or more processors and one or more computer-readable storage media storing instructions that, when executed by the one or more processors, control at least the conveyance system to subject the substrate to a thermal shock, wherein the thermal shock comprises exposing the substrate to a temperature of at least 1000 K for a duration of 60 seconds or less.

75. The system of claim 74, wherein the one or more computer-readable storage media store additional instructions that, when executed by the one or more processors, further cause the control system to control the duration of the thermal shock by moving, via the conveyance system, the first portion of the conveyance member into, within, and / or out of the furnace.

76. The system of claim 74, wherein the thermal shock is effective to convert the one or more precursors into a plurality of multi-element nanoparticles on the substrate.

77. The system of claim 74, wherein the thermal shock is effective to convert the one or more precursors into one or more sintered structures.

78. The system of claim 68, wherein the furnace is configured as a tube furnace.

79. The system of claim 68, wherein the furnace is configured as a plate furnace.

80. The system of claim 68, wherein the conveyance member is movable between the first position, which is outside the furnace, and the second position, which is inside the furnace.

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