Nanoscale high-entropy carbides and their preparation methods, high-entropy composite materials, electrocatalytic electrodes and fuel cells

Abstract

This application discloses a nano-high-entropy carbide, its preparation method, a high-entropy composite material, an electrocatalytic electrode, and a fuel cell. The method for preparing the nano-high-entropy carbide includes: providing shaped CNTs; mixing a carbon source, multiple metal sources, and a solvent to obtain a precursor solution; coating the precursor solution onto the shaped CNTs; applying an electric current to the shaped CNTs to generate Joule heating; and obtaining the nano-high-entropy carbide after heating, holding, and cooling. The nano-high-entropy carbide comprises 5 to 22 metal elements, which form a high-entropy phase with carbon. The average particle size of the nano-high-entropy carbide is 10 to 100 nm. According to the embodiments of this application, the nano-high-entropy carbide exhibits high stability, good electrical conductivity, and high chemical activity.

Description

Technical Field

[0001] This application relates to a nano-high-entropy carbide and its preparation method, a high-entropy composite material, an electrocatalytic electrode, and a fuel cell. Background Technology

[0002] Nano-carbide exhibits remarkable mechanical properties, good electrical conductivity, and high resistance to oxidation and corrosion. High-entropy structures can further enhance the performance of nano-carbide and achieve new functions that are impossible with few components, such as extremely high hardness and elastic modulus, better thermal insulation, and better electrochemical stability. This makes high-entropy nano-carbide (HENCs) highly anticipated in advanced applications such as mechanical engineering, energy storage and conversion, and aerospace.

[0003] To date, the composition and types of metal elements in high-entropy nanocarbides are limited, which restricts their applications. Summary of the Invention

[0004] This application provides a nano-high-entropy carbide and its preparation method, a high-entropy composite material, an electrocatalytic electrode, and a fuel cell, which have high stability, good electrical conductivity, and high chemical activity.

[0005] In one aspect, embodiments of this application provide a method for preparing nano-high-entropy carbides, comprising: providing shaped CNTs; mixing a carbon source, multiple metal sources, and a solvent to obtain a precursor solution; coating the precursor solution onto the shaped CNTs; applying an electric current to the shaped CNTs to generate Joule heating; and obtaining nano-high-entropy carbides after heating, holding, and cooling. The heating temperature is above 2750 K for 10-500 ms, the holding temperature is 1800-2200 K for 0 s and less than or equal to 60 s, and the cooling rate is 10%. 3 ~10 4 K s -1 Nano-high entropy carbides include 5 to 22 kinds of metal elements, which form a high entropy phase with carbon elements; the average particle size of nano-high entropy carbides is 10 to 100 nm.

[0006] This application utilizes extremely high heating temperatures, holding periods, and ultra-rapid cooling rates to obtain pure-phase nano-high-entropy carbides containing 5 to 22 metallic elements. These pure-phase nano-high-entropy carbides exhibit high stability, good electrical conductivity, and high chemical activity.

[0007] In some embodiments, the heat preservation time is 5~20s.

[0008] In some embodiments, the precursor solution is dip-coated onto shaped CNTs, and then an electric current is applied to the shaped CNTs to generate Joule heating. After heating, holding, and cooling, nano-high-entropy carbides are obtained. The applied current includes applying a heating current and applying a holding current. The heating current includes applying a current with a power density of 500-1000 W / cm² for 10-500 ms. 2 The applied current, including the current for heat preservation, includes the current applied for a duration greater than 0 seconds and less than or equal to 60 seconds, with a power density of 100~400W / cm². 2 The current.

[0009] In some embodiments, the carbon source includes a carbon source molecule having a carbon atom number of less than or equal to 6.

[0010] In some embodiments, the carbon source includes one or more of urea, methane, alanine, and glucose.

[0011] In some embodiments, the multiple metal sources include one or more of metal chlorides and metal complexes.

[0012] In some embodiments, the metal chloride includes one or more of MgCl2, VCl3, CrCl3, MnCl2, FeCl3, CoCl2, NiCl2, CuCl2, ZnCl2, YCl3, ZrCl4, NbCl5, MoCl5, RuCl3, SnCl2, SbCl3, CeCl3, PrCl3, NdCl3, SmCl3, EuCl3, GdCl3, TbCl3, DyCl3, HoCl3, ErCl3, TmCl3, YbCl3, LuCl3, HfCl4, TaCl5, WCl6, and IrCl3, and the metal complex includes one or more of H2PtCl6 and HAuCl4.

[0013] In some embodiments, the ratio of metal element concentration to carbon atom concentration in the precursor solution is (0.2~5):1.

[0014] In some embodiments, the total metal ion concentration in the precursor solution is 0.01~0.8M.

[0015] In some embodiments, molded CNTs include any one of CNT films, CNT fibers, and CNT foams.

[0016] In some embodiments, the average spacing between adjacent CNTs in the molded CNTs is 10~20 nm.

[0017] In some embodiments, the method for preparing shaped CNTs includes: ultrasonically dispersing commercial CNTs, disordered CNTs synthesized by chemical vapor deposition, arrayed CNTs, and solvent; the ultrasonic dispersion power is 400~1000W, and the time is 1~20min.

[0018] Secondly, embodiments of this application provide a nano-high entropy carbide, which includes 5 to 22 metal elements, and the 5 to 22 metal elements and carbon elements form a high entropy phase; wherein the average particle size of the nano-high entropy carbide is 10 to 100 nm.

[0019] In some embodiments, the nano-high entropy carbide includes 10 to 22 metallic elements.

[0020] In some embodiments, the nano-high entropy carbide includes 20 to 22 metallic elements.

[0021] In some embodiments, the metallic element includes any one of Pt, Au, Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, Sn, Sb, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, and Ir.

[0022] In some embodiments, nano-high entropy carbides include those with the general formula MC. x The high-entropy phase carbide; wherein M includes 5 to 22 metallic elements, the metallic elements including any one of Pt, Au, Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, Sn, Sb, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W and Ir.

[0023] In some embodiments, nano-high entropy carbides include (PtWTaFeNi)C x 、(PtWTaHfCe)C x 、(VCrZnZrNbHfIrAu)C x (VCrMnFeCoNiNbMoTaW)C x , (MgCrMnCuZnYMoSnCeHfTaWIrPtAu)C x , (MgVCrMnFeCoNiCuZnZrYNbMoRuSnCeHfTaWIrPtAu)C x Any one of them.

[0024] In some embodiments, the Span value (D) of nano-high-entropy carbides v90-D v 10) / D v 50 = 0.5~10.

[0025] In some embodiments, based on the phase state of nano-high-entropy carbides, the content of the high-entropy phase is 95.0%~100.0%.

[0026] In some embodiments, based on the phase state of nano-high-entropy carbides, the content of the high-entropy phase is 98.0%~100.0%.

[0027] In some embodiments, based on the phase state of nano-high-entropy carbides, the content of the high-entropy phase is 99.9%~100.0%.

[0028] Thirdly, embodiments of this application provide a high-entropy composite material, including a molded CNT matrix and nano-high-entropy carbides disposed on at least a portion of the surface of the molded CNT matrix. The nano-high-entropy carbides include 5 to 22 metal elements, and the 5 to 22 metal elements and carbon elements form a high-entropy phase. The average particle size of the nano-high-entropy carbides is 10 to 100 nm.

[0029] Fourthly, embodiments of this application provide an electrocatalytic electrode comprising the high-entropy composite material described in the third aspect.

[0030] Fifthly, embodiments of this application provide a fuel cell comprising the nano-high-entropy carbide of the second aspect. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This diagram illustrates a method for preparing nano-high-entropy carbides according to some embodiments of this application.

[0033] Figure 2 Typical temperature curves are shown in some embodiments of the present application for the preparation of nano-high entropy carbides.

[0034] Figure 3 The transmission electron microscope (TEM) image and particle size distribution of the nano-high entropy carbide in Example 1 of this application are shown, where a is the TEM particle size distribution and b is the TEM image.

[0035] Figure 4The images are scanning electron microscope (SEM) images of carbon-based heating sources loaded with nano-high entropy carbides in Examples 1 and Comparative Examples 3-6, where a is the CNT film in Example 1, b is the hydrophilic carbon paper in Comparative Example 3, c is the hydrophobic carbon paper in Comparative Example 4, d is the hydrophilic carbon cloth in Comparative Example 5, and d is the hydrophobic carbon cloth in Comparative Example 6.

[0036] Figure 5 The images shown are EDS surface scans of the high-entropy nanocarbides in Examples 1-6, where a is the EDS surface scan of the high-entropy nanocarbides in Example 1, b is the EDS surface scan of the high-entropy nanocarbides in Example 2, c is the EDS surface scan of the high-entropy nanocarbides in Example 3, d is the EDS surface scan of the high-entropy nanocarbides in Example 4, e is the EDS surface scan of the high-entropy nanocarbides in Example 5, and f is the EDS surface scan of the high-entropy nanocarbides in Example 6.

[0037] Figure 6 The XRD diffraction patterns of the nano-high entropy carbides in Examples 1-6 are shown below. Specifically, 5-HENCs are the XRD diffraction patterns of the nano-high entropy carbides in Example 1, 8-HENCs are the XRD diffraction patterns of the nano-high entropy carbides in Example 3, 10-HENCs are the XRD diffraction patterns of the nano-high entropy carbides in Example 4, 15-HENCs are the XRD diffraction patterns of the nano-high entropy carbides in Example 5, and 22-HENCs are the XRD diffraction patterns of the nano-high entropy carbides in Example 6.

[0038] Figure 7 The graph shows the HER and OER performance of the nano-high entropy carbide in Example 1.

[0039] Figure 8 The diagram shows the total water-splitting performance of the nano-high-entropy carbide in Example 1.

[0040] Figure 9 The graph shows the alcohol oxidation performance of the nano high-entropy carbide in Example 2, where a represents alcohol oxidation, b represents ethanol oxidation, and c represents ethylene glycol oxidation.

[0041] The accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0042] To better understand the above-mentioned objectives, features, and advantages of this application, the solution of this application will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0043] Many specific details are set forth in the following description in order to provide a full understanding of this application, but this application may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of this application, and not all embodiments.

[0044] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the present application, including nano-high-entropy carbides, their preparation methods, high-entropy composite materials, electrocatalytic electrodes, and fuel cells. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter of the claims.

[0045] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0046] Unless otherwise specified, all embodiments and optional embodiments of this application may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of this application.

[0047] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions, and such technical solutions shall be deemed to be included in the disclosure of this application.

[0048] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0049] Unless otherwise specified, in this application, the terms "first," "second," etc., are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0050] In this application, the terms "multiple" or "various" refer to two or more kinds.

[0051] In the description of the embodiments of this application, unless otherwise specified, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0052] Unless otherwise stated, the test temperature for all parameters mentioned in this application is 25°C.

[0053] Precise control of the particle size, elemental composition, and elemental quantity of high-entropy carbide nanoparticles remains a challenge. These challenges stem from the difficulty of achieving the controlled reactions necessary for realizing high-entropy carbide nanoparticles. First, the entropy-driven reactions of carbides require extremely high growth temperatures (typically >2500 K), while maintaining the high-entropy lattice structure at high temperatures to room temperature (25 °C) requires a very rapid cooling process. Second, to prevent nanoparticle aggregation at high temperatures, extremely short growth processes and spatial confinement effects are required. Finally, compared to high-entropy alloys or oxide nanoparticles, the multi-component immiscibility problem is more pronounced in high-entropy carbide nanoparticles.

[0054] In view of this, embodiments of this application provide a nano-high-entropy carbide and its preparation method, a high-entropy composite material, an electrocatalytic electrode, and a fuel cell, which have high stability, good electrical conductivity, and high chemical activity.

[0055] Nano-high entropy carbides A nano-high entropy carbide comprising 5 to 22 metal elements, which form a high entropy phase with carbon; wherein the average particle size of the nano-high entropy carbide is 10 to 100 nm.

[0056] The nano-high-entropy carbides of this application contain 5 to 22 metal elements, all of which are dissolved in carbon to form a stable and singular high-entropy phase. The various metal elements in the high-entropy phase are mixed in approximately equimolar proportions to form a stable phase with high configurational entropy. The different atomic sizes of the heterogeneous metals lead to diversity in atomic coordination and lattice distortion, resulting in a "cocktail effect" that significantly enhances the stability, electrical conductivity, and chemical activity of the nano-high-entropy carbides.

[0057] The nano-high entropy carbides of this application embodiment also have nano-effects. The synergistic effect of heterogeneous metal atoms and nano-effects can enable nano-high entropy carbides to have high chemical activity and high stability even under extreme conditions.

[0058] Optionally, the nano-high entropy carbides include 10 to 22 metallic elements.

[0059] Alternatively, nano-high entropy carbides may include 20 to 22 metallic elements.

[0060] In some embodiments, the nano-high entropy carbide comprises 22 metallic elements.

[0061] The average particle size of the nano-high entropy carbide is independently selected from any value of 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm or any range between the two.

[0062] In some embodiments, the metallic element includes any one of Pt, Au, Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, Sn, Sb, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, and Ir.

[0063] The embodiments of this application contain nano-high entropy carbides with suitable types of metal elements that can enhance the "cocktail effect," thereby better improving the stability, electrical conductivity, and chemical activity of the nano-high entropy carbides.

[0064] In some embodiments, nano-high entropy carbides include those with the general formula MC. xThe high-entropy phase carbide; wherein M includes 5 to 22 metallic elements, the metallic elements including any one of Pt, Au, Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, Sn, Sb, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W and Ir.

[0065] General formula MC x M can include 5 to 22 metallic elements, and x can be determined based on the valence of M, so that MC x In equilibrium of chemical valences. For example, MC. x When it contains 5 metallic elements, the general formula can be M1M2M3M4M5C x Where M1, M2, M3, M4, and M5 represent different metallic elements; MC x When containing 10 metallic elements, the general formula can be M1M2M3M4M5M6M7M8M9M 10 C x Among them, M1, M2, M3, M4, M5, M6, M7, M8, M9, M 10 They represent different metallic elements; MC x When containing 20 metallic elements, the general formula can be M1M2M3M4M5M6M7M8M9M 10 M 11 M 12 M 13 M 14 M 15 M 16 M 17 M 18 M 19 M 20 C x Among them, M1, M2, M3, M4, M5, M6, M7, M8, M9, M 10 M 11 M 12 M 13 M 14 M 15 M 16 M 17 M 18 M 19 M 20 They represent different metallic elements; MC x When containing 22 metallic elements, the general formula can be M1M2M3M4M5M6M7M8M9M 10 M 11 M 12 M 13 M14 M 15 M 16 M 17 M 18 M19M 20 M 21 M 22 C x Among them, M1, M2, M3, M4, M5, M6, M7, M8, M9, M 10 M 11 M 12 M 13 M 14 M 15 M 16 M 17 M 18 M 19 M 20 M 21 M 22 They represent different metallic elements.

[0066] In some embodiments, the Span value (D) of nano-high-entropy carbides v 90-D v 10) / D v 50 = 0.5~10.

[0067] Having a suitable range of Span values ​​can make the particle size distribution of high-entropy nanocarbides more uniform, thereby making high-entropy nanocarbides more nano-effect-like.

[0068] Optionally, the Span value of the nano-high-entropy carbide is independently selected from any value or a range between 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, and 10.0.

[0069] In some embodiments, based on the phase state of nano-high-entropy carbides, the content of the high-entropy phase is 95.0%~100.0%.

[0070] Optionally, the content of the high-entropy phase is 98.0%~100.0%.

[0071] Alternatively, based on the phase state of nano-high-entropy carbides, the content of the high-entropy phase is 99.9%~100.0%.

[0072] In some embodiments, based on the phase state of nano-high-entropy carbides, the content of the high-entropy phase is 100.0%.

[0073] Nanoscale high-entropy carbides possess a single high-entropy phase, which can reduce the adverse effects of impurities on stability, electrical conductivity, and chemical activity.

[0074] In some embodiments, nano-high-entropy carbides are obtained by placing shaped CNTs loaded with a precursor and a carbon source in an inactive atmosphere and / or a reducing atmosphere, followed by heating, holding, and cooling. The precursor includes a metal source containing 5 to 22 metal elements; the heating temperature is above 2750 K for 10 to 500 ms, the holding temperature is 1800 to 2200 K for a time greater than 0 s and less than or equal to 60 s, and the cooling rate is 10. 3 ~10 4 K s -1 .

[0075] In this embodiment, an extremely high temperature above 2750K is achieved through instantaneous heating, allowing the precursor containing multiple metal elements to disperse rapidly and undergo better carbonization. Subsequently, holding at 1800-2200K for a suitable time allows for the diffusion of multiple metal atoms and particle fusion, forming nanoparticles with a single-phase lattice. Finally, extremely rapid cooling reduces the temperature of the nano-high-entropy carbides to room temperature (25°C). Due to the extremely rapid cooling rate, the nano-high-entropy carbides lack time for phase separation, thereby reducing the formation of impurity phases.

[0076] Preparation method of nano high-entropy carbide A method for preparing nano-high-entropy carbides includes: providing shaped CNTs; mixing a carbon source, multiple metal sources, and a solvent to obtain a precursor solution; coating the precursor solution onto the shaped CNTs; applying an electric current to the shaped CNTs to generate Joule heating; and obtaining nano-high-entropy carbides after heating, holding, and cooling. The nano-high-entropy carbides comprise 5-22 metal elements, which form a high-entropy phase with carbon. The heating temperature is above 2750 K for 10-500 ms, the holding temperature is 1800-2200 K for a time greater than 0 s and less than or equal to 60 s, and the cooling rate is 10%. 3 ~10 4 K s -1 Among them, the average particle size of the nano-high entropy carbide is 10~100nm.

[0077] Optionally, the heat preservation time is 5~20 seconds.

[0078] Carbothermal shock methods in related technologies typically involve short thermal pulses at temperatures of 1500–2000 K. While laser scanning ablation can generate higher-temperature thermal pulses at the nanosecond level, the ultrashort reaction time cannot meet the conditions for atomic diffusion to form a single phase in nano-high-entropy carbides, and the introduction of a carbon source also presents challenges. Methods for synthesizing high-entropy carbides, such as spark plasma sintering, electrochemical synthesis, and carbothermal reduction, generally have relatively slow cooling rates (<10 K). 3 K s 1 The use of heating methods, or prolonged heating times (typically exceeding 5 minutes), is detrimental to the formation of single-phase nanocarbides. Furthermore, carbides synthesized by these methods are often limited to specific metal elements, greatly restricting the diverse design of nano-high-entropy carbides.

[0079] Therefore, in this embodiment, molded CNTs are used as a carbon-based heating source. By connecting graphite clips as electrodes to both ends of the molded CNTs and passing an electric current through them, Joule heating is generated in the molded CNTs, allowing the precursor and carbon source to undergo preset heating, holding, and cooling steps. Because molded CNTs have better structural stability and superior electrical and thermal conductivity, they can generate a large amount of Joule heat and rapidly heat themselves. Therefore, extremely high temperatures and ultra-fast heating / cooling rates can be achieved through Joule heating. Furthermore, molded CNTs can also serve as a growth substrate. The gaps between CNTs in the molded CNTs can act as spatial confinement, reducing the aggregation of nano-high-entropy carbides and obtaining high-entropy carbides with nanoscale dimensions.

[0080] In this embodiment, an extremely high temperature above 2750K is achieved through instantaneous heating, allowing the precursor to disperse rapidly and undergo carbonization. At this extremely high temperature, the entropy-driven effect is significantly enhanced, promoting elemental mixing and facilitating nucleation. This, in turn, enables further phase purification through atomic diffusion and particle fusion.

[0081] Subsequently, holding at 1800–2200 K for an appropriate time helps to further purify the high-entropy phase. During this process, the carbide nuclei continue to mix and grow, and entropy drives the heterogeneous intermediates to form nanoparticles with a single-phase lattice through atomic diffusion and particle fusion. Due to the extremely high temperature obtained during heating, the holding time can be effectively shortened, thereby reducing the aggregation of nano-high-entropy carbides; it can also reduce the problem of incomplete purification of the high-entropy phase caused by excessively short holding times, and reduce the formation of impurity phases.

[0082] Finally, the nano-high-entropy carbides are cooled at an extremely rapid rate to room temperature (25°C). Due to the extremely fast cooling rate, the nano-high-entropy carbides lack the time for phase separation, thereby reducing the formation of impurity phases.

[0083] In this embodiment, the heating, heat preservation, and cooling are all carried out under a preset atmosphere to reduce the influence of oxidizing gas on the formation of nano-high entropy carbides. The atmosphere can be an inactive atmosphere, such as at least one of nitrogen, argon, and neon; it can also be a reducing atmosphere, such as hydrogen; or it can be a mixed atmosphere of inactive and reducing atmospheres, such as a mixture of hydrogen and argon.

[0084] Optionally, the heating temperature is independently selected from any value or a range between any two of 2750K, 2800K, 2850K, 2900K, 2950K, 3000K, 3050K, 3100K, 3150K, 3200K, 3250K, 3300K, 3350K, 3400K, 3450K, 3500K, 3550K, 3600K, 3650K, 3700K, 3850K, 3900K, 3950K, 4000K, 4100K, 4200K, 4300K, 4400K, 4500K, 4600K, 4700K, 4800K, 4900K, and 5000K.

[0085] Optionally, the heating time can be independently selected from 10ms, 20ms, 30ms, 40ms, 50ms, 60ms, 70ms, 80ms, 90ms, 100ms, 110ms, 120ms, 130ms, 140ms, 150ms, 160ms, 170ms, 180ms, 190ms, 200ms, 210ms, 220ms, 230ms, 240ms, 250ms, and 260ms. The value can be any value from 270ms, 280ms, 290ms, 300ms, 310ms, 320ms, 330ms, 340ms, 350ms, 360ms, 370ms, 380ms, 390ms, 400ms, 410ms, 420ms, 430ms, 440ms, 450ms, 460ms, 470ms, 480ms, 490ms, and 500ms, or a range between any two.

[0086] Optionally, the insulation temperature is independently selected from any value or a range between 1800K, 1850K, 1900K, 1950K, 2000K, 2050K, 2100K, 2150K, and 2200K.

[0087] Optionally, the heat preservation time can be independently selected from 1s, 2s, 3s, 4s, 5s, 6s, 7s, 8s, 9s, 10s, 11s, 12s, 13s, 14s, 15s, 16s, 17s, 18s, 19s, 20s, 21s, 22s, 23s, 24s, 25s, 26s, 27s, 28s, 29s, 30s, 31s, 3 Any value from 2s, 33s, 34s, 35s, 36s, 37s, 38s, 39s, 40s, 41s, 42s, 43s, 44s, 45s, 46s, 47s, 48s, 49s, 50s, 51s, 52s, 53s, 54s, 55s, 56s, 57s, 58s, 59s, 60s, or a range between any two.

[0088] In some embodiments, the precursor solution is dip-coated onto shaped CNTs, and then an electric current is applied to the shaped CNTs to generate Joule heating. After heating, holding, and cooling, nano-high-entropy carbides are obtained. The applied current includes applying a heating current and applying a holding current. The heating current includes applying a current with a power density of 500-1000 W / cm² for 10-500 ms. 2 The applied current, including the current for heat preservation, includes the current applied for a duration greater than 0 seconds and less than or equal to 60 seconds, with a power density of 100~400W / cm². 2 The current.

[0089] This application uses molded CNTs as a carbon-based heating source. By connecting graphite clips as electrodes to both ends of the molded CNTs and applying an electric current, the molded CNTs generate Joule heat, allowing the precursor and carbon source to undergo preset heating, holding, and cooling steps. Because molded CNTs have better structural stability and superior electrical and thermal conductivity, they can generate a large amount of Joule heat and rapidly heat up. Therefore, extremely high temperatures and ultra-fast heating / cooling rates can be achieved through Joule heating. Specifically, the power density applied for 10~500ms is 500~1000W / cm². 2 The current can rapidly heat the molded CNTs to above 2750K; subsequently, an application of a power density of 100~400W / cm³ for a period greater than 0s and less than or equal to 60s is applied. 2 The applied current allows the molded CNTs to be held at 1800~2200K for 0~60s; finally, the applied current is removed, and the molded CNTs will recoil at 10... 3 ~10 4 K s -1 The cooling rate drops to room temperature.

[0090] Optionally, the power density of the heating current is independently selected from 500 W / cm². 2 550W / cm 2600W / cm 2 650W / cm 2 700W / cm 2 750W / cm 2 800W / cm 2 850W / cm 2 900W / cm 2 950W / cm 2 1000W / cm 2 Any value in the range or any value between the two.

[0091] Optionally, the application time of the heating current is independently selected from 10ms, 20ms, 30ms, 40ms, 50ms, 60ms, 70ms, 80ms, 90ms, 100ms, 110ms, 120ms, 130ms, 140ms, 150ms, 160ms, 170ms, 180ms, 190ms, 200ms, 210ms, 220ms, 230ms, 240ms, 250ms, 260ms. The value can be any value from ms, 270ms, 280ms, 290ms, 300ms, 310ms, 320ms, 330ms, 340ms, 350ms, 360ms, 370ms, 380ms, 390ms, 400ms, 410ms, 420ms, 430ms, 440ms, 450ms, 460ms, 470ms, 480ms, 490ms, and 500ms, or a range between any two.

[0092] Optionally, the power density of the insulation current is independently selected from 100 W / cm². 2 150W / cm 2 200W / cm 2 250W / cm 2 300W / cm 2 350W / cm 2 400W / cm 2 Any value in the range or any value between the two.

[0093] Optionally, the application time of the heat-insulating current is independently selected from 1s, 2s, 3s, 4s, 5s, 6s, 7s, 8s, 9s, 10s, 11s, 12s, 13s, 14s, 15s, 16s, 17s, 18s, 19s, 20s, 21s, 22s, 23s, 24s, 25s, 26s, 27s, 28s, 29s, 30s, and 31s. Any value from 32s, 33s, 34s, 35s, 36s, 37s, 38s, 39s, 40s, 41s, 42s, 43s, 44s, 45s, 46s, 47s, 48s, 49s, 50s, 51s, 52s, 53s, 54s, 55s, 56s, 57s, 58s, 59s, 60s, or a range between any two.

[0094] In some embodiments, the interval between applying the heating current and applying the heat preservation current is t, where 0 ≤ t ≤ 30 s.

[0095] In this embodiment of the application, a heating current can be applied immediately after the heating current is applied, or a heat preservation current can be applied at intervals.

[0096] In some embodiments, the step of dip-coating the precursor solution onto the molded CNTs includes: dip-coating the precursor solution onto the molded CNTs 1 to 10 times, and drying in air at 60°C for 1 to 10 minutes after each dip-coating.

[0097] In some embodiments, the multiple metal sources include one or more of metal chlorides and metal complexes.

[0098] In some embodiments, the carbon source includes a carbon source molecule having a carbon atom number of less than or equal to 6.

[0099] Optionally, the number of carbon atoms in the carbon source molecule can be 1, 2, 3, 4, 5, 6, or any range of the above values.

[0100] Optionally, the carbon source includes one or more of urea, methane, alanine, and glucose.

[0101] Small carbon sources can be decomposed more easily, thus forming nuclei with metal elements.

[0102] Optionally, the metal chloride includes one or more of MgCl2, VCl3, CrCl3, MnCl2, FeCl3, CoCl2, NiCl2, CuCl2, ZnCl2, YCl3, ZrCl4, NbCl5, MoCl5, RuCl3, SnCl2, SbCl3, CeCl3, PrCl3, NdCl3, SmCl3, EuCl3, GdCl3, TbCl3, DyCl3, HoCl3, ErCl3, TmCl3, YbCl3, LuCl3, HfCl4, TaCl5, WCl6, and IrCl3, and the metal complex includes one or more of H2PtCl6 and HAuCl4.

[0103] In some embodiments, the ratio of metal element concentration to carbon atom concentration in the precursor solution is (0.2~5):1.

[0104] Having a suitable concentration ratio of metal and carbon elements can reduce the possibility of metal and / or carbon element precipitation, thereby reducing the possibility of impurity phases formed between precipitated elements and / or between precipitated and unprecipitated elements, and thus improving the purity of single-phase nano-high-entropy carbides.

[0105] Optionally, the ratio of metal element concentration to carbon element concentration in the precursor solution is independently selected from 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2. The range of values ​​from 5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4.0:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.7:1, 4.8:1, 4.9:1, 5.0:1, or any value between any two of these ranges.

[0106] In some embodiments, the total metal ion concentration in the precursor solution is 0.01~0.8M.

[0107] Optionally, the total metal ion concentration in the precursor solution is independently selected from 0.01M, 0.02M, 0.03M, 0.04M, 0.05M, 0.06M, 0.07M, 0.08M, 0.09M, 0.10M, 0.11M, 0.12M, 0.13M, 0.14M, 0.15M, 0.16M, 0.17M, and 0.18M. , 0.19M, 0.20M, 0.21M, 0.22M, 0.23M, 0.24M, 0.25M, 0.26M, 0.27M, 0.28M, 0.2 9M, 0.30M, 0.31M, 0.32M, 0.33M, 0.34M, 0.35M, 0.36M, 0.37M, 0.38M, 0.39M, 0. 40M, 0.41M, 0.42M, 0.43M, 0.44M, 0.45M, 0.46M, 0.47M, 0.48M, 0.49M, 0.50M, 0.51M, 0.52M, 0.53M, 0.54M, 0.55M, 0.56M, 0.57M, 0.58M, 0.59M, 0.60M, 0.61M The range of values ​​from 0.62M, 0.63M, 0.64M, 0.65M, 0.66M, 0.67M, 0.68M, 0.69M, 0.70M, 0.71M, 0.72M, 0.73M, 0.74M, 0.75M, 0.76M, 0.77M, 0.78M, 0.79M, and 0.8M, or any value between any two.

[0108] In some embodiments, molded CNTs include any one of CNT films, CNT fibers, and CNT foams.

[0109] Compared to other carbon-based heating sources, such as hydrophilic carbon paper (CP), hydrophobic carbon paper (CP-P), hydrophilic carbon cloth (CC), and hydrophobic carbon cloth (CC-P), these carbon-based heating sources have lower electrical and thermal conductivity and contain micron-sized fibers. Therefore, the heating temperature is lower, making it difficult to obtain high-entropy carbides with multiple metal elements, and the resulting carbide particles are larger.

[0110] The CNTs film in this application is a flexible film formed by random interweaving of CNTs; the CNTs fiber is a continuous fiber made by wet spinning or direct spinning; the CNTs foam has a three-dimensional porous lightweight structure. Molded CNTs with a suitable structure can generate Joule heating under applied current, allowing them to rapidly heat to extremely high temperatures, and then rapidly cool down after the current is removed. Furthermore, the gaps between CNTs in the molded CNTs can act as spatial confinement, reducing the aggregation of nano-high-entropy carbides and resulting in high-entropy carbides with nanoscale dimensions.

[0111] In some embodiments, the average spacing between adjacent CNTs in the molded CNTs is 10~20 nm.

[0112] An average spacing between adjacent CNTs with a suitable range can better serve as a spatial confinement mechanism, leading to high-entropy carbides with nanoscale dimensions.

[0113] Optionally, the average spacing between adjacent CNTs is independently selected from any value of 10nm, 11m, 12m, 13m, 14m, 15m, 16m, 17m, 18m, 19, 20nm or a range between any two.

[0114] In some embodiments, the method for preparing shaped CNTs includes: ultrasonically dispersing commercial CNTs, disordered CNTs synthesized by chemical vapor deposition, arrayed CNTs and solvent, wherein the ultrasonic dispersion power is 400~1000W and the time is 1~20min.

[0115] By mixing and molding CNTs with different structures and synthesis methods, the molded CNTs can better achieve extremely high temperatures and ultra-fast heating / cooling rates through Joule heating; at the same time, the molded CNTs can have better spatial confinement.

[0116] In some embodiments, after ultrasonically dispersing commercial CNTs, disordered CNTs synthesized by chemical vapor deposition, arrayed CNTs, and solvent, a filtration process is further included to separate the formed CNTs from the solvent. For example, commercial CNTs, disordered CNTs synthesized by chemical vapor deposition, arrayed CNTs, or other types of CNTs can be ultrasonically dispersed in ethanol and then filtered. The ultrasonic method used can be as follows: 10-50 mg of CNTs are ultrasonically dispersed in 100-500 mL of ethanol at 400-1000 W using a high-power probe for 1-20 min, and then the suspension is immediately transferred to a filtration device to form a CNT membrane on filter paper by vacuum filtration.

[0117] In some embodiments, the shaped CNTs are further subjected to a pore-forming process, wherein the pore diameter is 10~500μm. This allows gas to escape.

[0118] Example The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0119] Example 1 Preparation of CNTs formed by carbon-based heating source Using acetylene gas as a precursor and metallic iron nanoparticles as a catalyst, single-walled carbon nanotubes (SACNTs) were prepared on silicon wafers via low-pressure chemical vapor deposition. 20 mg of SACNTs were placed in 250 ml of ethanol and dispersed for 5 min at 600 W using a high-power probe (SCIENTZ-950E). The suspension was then immediately transferred to a vacuum filter, and a 40 mm diameter carbon nanotube film (CNT film) was formed on filter paper through vacuum filtration. After thorough air drying, the CNT film was cut into rectangular shapes, and micron-sized pores (40 μm in diameter and 800 μm spacing) were drilled using a direct laser writer (1064 nm wavelength) to effectively release bubbles generated during organic waste incineration (OWS).

[0120] Preparation of high-entropy nanocarbides Metal sources H₂PtCl₆, WCl₆, TaCl₅, FeCl₃, NiCl₂ and carbon source CH₄N₂O were dissolved in ethanol as a precursor solution, wherein the atomic ratio of metal elements to carbon elements was 2:3 and the total metal ion concentration in the precursor solution was 0.05 M. The precursor solution was then dip-coated onto a carbon nanotube film (CNTs film) and dried in air at 60 °C for 2 min. Subsequently, the CNTs film carrying the precursor was inserted into a circuit with graphite clips as electrodes and subjected to Joule heating in a mixed atmosphere of 10% hydrogen (H₂) and 90% argon (Ar). After heating, holding, and cooling, a high-entropy composite material was obtained. The high-entropy composite material includes a molded CNT matrix and single-crystal nano-high-entropy carbides (PtWTaFeNi)C on the surface of the molded CNT matrix. x (PtWTaFeNi)C x The average particle size is 20 nm, the purity is 100%, and the heating process includes applying a power density of 800 W / cm³. 2 A current was applied for 50 ms to raise the temperature of the CNT film to 2750 K. The holding process included applying a power density of 240 W / cm². 2The applied current was applied for 5 seconds, which held the CNT film at 2000 K for 5 seconds. The cooling process involved removing the applied current, which allowed the CNT film to be cooled at an ultra-fast rate of 7800 K / s.

[0121] The temperature of the CNTs film was measured in situ using infrared thermometers (Optrics, PI640 & PI05M).

[0122] Performance testing Electrochemical measurements were performed using a CHI 660e / 760e electrochemical workstation, employing a standard three-electrode method at room temperature. The prepared high-entropy composite material was used directly as the working electrode, Hg / HgO as the reference electrode, and Pt as the counter electrode. The electrolyte was 1M KOH, and the temperature was room temperature or 60℃. Polarization curves were plotted at 5 mV. s 1 The scan rate was measured and compensated for at 85%. No additional compensation was used for stability testing. To maintain the pH and level of the electrolyte during long-term testing, deionized water was continuously replenished using a microsyringe.

[0123] Figures 7-8 The (PtWTaFeNi)C model is shown. x Hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and total water splitting (OWS) under high current density. As shown in the figure, the synthesized (PtWTaFeNi)C... x It exhibits a very stable hydrogen evolution reaction (HER) at 2000 / 5000 mA. cm 2 Under these conditions, the potential change is only 4.5% / 7.1% over 600 / 320 hours, and the overall water splitting (OWS) cell voltage under industrial conditions is only 1.63 V (3000mA). cm 2 Additionally, the synthesized (PtWTaFeNi)C x After high-temperature growth, it adheres firmly to a CNT thin film substrate with good conductivity, and therefore can be directly used as a HER and OER electrode.

[0124] Figure 5 and Figure 6 (PtWTaFeNi)C x Energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) images were obtained. The figures show that (PtWTaFeNi)C... x It is a single-phase structure with a pure phase.

[0125] Examples 2-6 The experimental procedures and performance tests are the same as in Example 1, except that the metal source, heating, holding and cooling parameters are different in the preparation of nano high-entropy carbides. See Table 1 and Table 2 for details.

[0126] Comparative Example 1 The experimental procedures and performance tests were the same as in Example 1, except that the heat preservation was not performed in the preparation of the nano high-entropy carbide. See Tables 1 and 2 for details.

[0127] Comparative Example 2 The experimental procedures and performance tests were the same as in Example 6, except that the heat preservation was not performed in the preparation of nano high-entropy carbides. See Tables 1 and 2 for details.

[0128] Table 1

[0129]

[0130] Table 2

[0131] As shown in Table 1, the metal elements and carbon elements in Examples 1-6, after heating, holding, and cooling treatments, can yield pure-phase nano-high-entropy carbides. However, Comparative Example 1, which does not involve holding, cannot sustain the mixing and growth of carbide nuclei formed during the heating process, resulting in a large number of impurity phases. Comparative Example 2 differs from Example 6 only in that it does not involve holding. Since Comparative Example 2 contains 22 different metal elements, it produces a large number of carbide impurity phases with fewer than 22 metal elements.

[0132] Comparative Examples 3-6 The experimental procedures and performance tests are the same as in Example 1, except that the carbon-based heating source is different, as detailed in Table 3.

[0133] Table 3

[0134] Figure 4 Scanning electron microscope (SEM) images of the products from Example 1 and Comparative Examples 3-6. (From Table 3 and...) Figure 4 It is known that using CNT thin films as a carbon-based heating source can, on the one hand, play a role in spatial confinement, thereby reducing the possibility of agglomeration of nano-high-entropy carbides and thus reducing the average particle size of nano-high-entropy carbides; on the other hand, it can also increase the heating temperature so that various metal elements and carbon elements can form a high-entropy phase.

[0135] like Figure 1As shown in the embodiments of this application, a large voltage pulse is applied to the CNTs film of the load precursor in an atmosphere of H2 / Ar mixture, H2, Ar, or N2, and its temperature is instantaneously raised to 2750K by Joule heating, with a heating rate of 103~105K. s -1 In this step, the metal precursor rapidly disperses and carbonizes. At high temperatures, the entropy-driven effect is significantly enhanced, promoting elemental mixing and facilitating nucleation, which in turn allows for further phase purification through atomic diffusion and particle fusion. Secondly, Joule self-heating, maintaining a preset time at 1800–2200 K, further purifies the nano-high-entropy carbide phase. In this step, carbide nuclei continuously mix and grow, and entropy drives the formation of nanoparticles with a single-phase lattice from the heterogeneous intermediates through atomic diffusion and particle fusion. Due to the ultra-high temperature pulse in the thermal pulse step, the stable growth time is effectively shortened, effectively preventing the aggregation of nano-high-entropy carbide particles. Finally, after removing the applied voltage, an ultra-fast cooling process is immediately implemented at a cooling rate of 10³–10⁴ K. s -1 Due to the lack of time for phase separation, the high-entropy phase formed at high temperature will be maintained until room temperature.

[0136] Figure 2 This is a typical temperature curve from an embodiment of this application, provided by... Figure 2 As can be seen, the embodiments of this application go through three processes: heating, stable growth, and cooling.

[0137] Figure 3 The image shows a transmission electron microscope (TEM) of the nano-high entropy carbide in Example 1. As can be seen from the figure, the average particle size of the nano-high entropy carbide is 20 nm.

[0138] Figure 9 The graph shows the alcohol oxidation performance of the nano-high entropy carbide in Example 2. As can be seen from the graph, the mass activity of the nano-high entropy carbide in Example 2 for methanol oxidation (MOR), ethanol oxidation (EOR), and ethylene glycol oxidation (EGOR) is 12.02 A. mg -1 Pt 3.97A mg -1 Pt and 23.45A mg -1 Pt These remarkable electrocatalytic capabilities are unattainable by traditional electrocatalysts or few-element nanocarbide materials.

[0139] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A method for preparing nano-high-entropy carbides, characterized in that, include: Provide molded CNTs; A precursor solution is obtained by mixing a carbon source, multiple metal sources, and a solvent. The precursor solution is dip-coated on the shaped CNTs, and Joule heat is generated by applying an electric current to the shaped CNTs, so that nanometer high-entropy carbides are obtained after temperature rising, temperature keeping and cooling, wherein the temperature rising is at a temperature of 2750K or above and for a time of 10-500ms, the temperature keeping is at a temperature of 1800-2200K and for a time of greater than 0s and less than or equal to 60s, and the cooling is at a speed of 10 3 ~10 4 K‧s -1 ; The nano-high entropy carbide comprises 5 to 22 metal elements, which together with carbon form a high entropy phase; wherein the average particle size of the nano-high entropy carbide is 10 to 100 nm.

2. The preparation method according to claim 1, characterized in that, The heat preservation time is 5~20s.

3. The preparation method according to claim 1, characterized in that, In the step of immersing the precursor solution onto the molded CNTs, applying an electric current to the molded CNTs to generate Joule heating, and obtaining nano-high-entropy carbides after heating, holding, and cooling, the following steps are performed. The applied current includes an applied heating current and an applied holding current. The applied heating current includes an applied current with a power density of 500-1000 W / cm² for 10-500 ms. 2 The applied heat-preserving current includes an application of a current greater than 0 s and less than or equal to 60 s with a power density of 100~400 W / cm². 2 The current.

4. The preparation method according to claim 1, characterized in that, The carbon source includes carbon source molecules having a carbon atom number of less than or equal to 6.

5. The preparation method according to claim 1, characterized in that, The carbon source includes one or more of urea, methane, alanine, and glucose.

6. The preparation method according to claim 1, characterized in that, The multiple metal sources include one or more of metal chlorides and metal complexes.

7. The preparation method according to claim 6, characterized in that, The metal chlorides include one or more of MgCl2, VCl3, CrCl3, MnCl2, FeCl3, CoCl2, NiCl2, CuCl2, ZnCl2, YCl3, ZrCl4, NbCl5, MoCl5, RuCl3, SnCl2, SbCl3, CeCl3, PrCl3, NdCl3, SmCl3, EuCl3, GdCl3, TbCl3, DyCl3, HoCl3, ErCl3, TmCl3, YbCl3, LuCl3, HfCl4, TaCl5, WCl6, and IrCl3, and the metal complexes include one or more of H2PtCl6 and HAuCl4.

8. The preparation method according to claim 1, characterized in that, The metal element concentration to carbon atom ratio in the precursor solution is (0.2~5):1; and / or, The total metal ion concentration in the precursor solution is 0.01~0.8M.

9. The preparation method according to claim 1, characterized in that, The molded CNTs include any one of CNT films, CNT fibers, and CNT foams; and / or, The average spacing between adjacent CNTs in the molded CNTs is 10~20nm.

10. The preparation method according to claim 1, characterized in that, The method for preparing the molded CNTs includes: The product was obtained by ultrasonic dispersion of commercial CNTs, disordered CNTs synthesized by chemical vapor deposition, arrayed CNTs, and solvent. The ultrasonic dispersion power is 400~1000W, and the time is 1~20min.

11. A nano-high-entropy carbide obtained by the preparation method according to any one of claims 1-10, characterized in that, The nano-high-entropy carbide comprises 5 to 22 metal elements, and the 5 to 22 metal elements and carbon elements form a high-entropy phase; The average particle size of the nano-high entropy carbide is 10~100nm.

12. The nano-high-entropy carbide according to claim 11, characterized in that, The nano-high-entropy carbides include 10 to 22 metallic elements; and / or, The nano-high entropy carbides include 20 to 22 kinds of metal elements.

13. The nano-high-entropy carbide according to claim 11, characterized in that, The metallic element includes any one of Pt, Au, Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, Sn, Sb, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, and Ir.

14. The nano-high-entropy carbide according to claim 11, characterized in that, The nano-high entropy carbides include those with the general formula MC x High-entropy phase carbides; M includes 5 to 22 metallic elements, including any one of Pt, Au, Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, Sn, Sb, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, and Ir.

15. The nano-high-entropy carbide according to claim 11, characterized in that, The nano-high entropy carbide includes (PtWTaFeNi)C x 、(PtWTaHfCe)C x 、(VCrZnZrNbHfIrAu)C x (VCrMnFeCoNiNbMoTaW)C x , (MgCrMnCuZnYMoSnCeHfTaWIrPtAu)C x , (MgVCrMnFeCoNiCuZnZrYNbMoRuSnCeHfTaWIrPtAu)C x Any one of them.

16. The nano-high-entropy carbide according to claim 11, characterized in that, The Span value (D) of the nano-high entropy carbide v 90-D v 10) / D v 50 = 0.5~10.

17. The nano-high-entropy carbide according to claim 11, characterized in that, Based on the phase state of the aforementioned high-entropy nanocarbide, the content of the high-entropy phase is 95.0%~100.0%; and / or, Based on the phase state of the aforementioned high-entropy nanocarbide, the content of the high-entropy phase is 98.0%~100.0%; and / or, Based on the phase state of the aforementioned high-entropy nanocarbide, the content of the high-entropy phase is 99.9%~100.0%.

18. A high-entropy composite material, characterized in that, It includes a shaped CNT matrix and a nano-high entropy carbide disposed on at least a portion of the surface of the shaped CNT matrix, wherein the nano-high entropy carbide includes the nano-high entropy carbide according to any one of claims 11-17.

19. An electrocatalytic electrode, characterized in that, Including the high-entropy composite material as described in claim 18.

20. A fuel cell, characterized in that, Includes the nano-high-entropy carbides according to any one of claims 11-17.

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