Nano high-entropy carbide and preparation method thereof, high-entropy composite material, electro-catalysis electrode and fuel cell

Abstract

The invention discloses a nano high-entropy carbide and a preparation method thereof, a high-entropy composite material, an electro-catalysis electrode and a fuel cell. The invention relates to a preparation method of nano high-entropy carbide. The preparation method comprises the following steps: providing molded CNTs; mixing a carbon source, a plurality of metal sources and a solvent to obtain a precursor solution; the formed CNTs are subjected to dip-coating with the precursor solution, then current is applied to the formed CNTs to generate Joule heat, nano high-entropy carbide is obtained after temperature rising, heat preservation and cooling, the nano high-entropy carbide comprises 5-22 metal elements, and the 5-22 metal elements and a carbon element form a high-entropy phase; wherein the average particle size of the nano high-entropy carbide is 10 to 100 nm. According to the embodiment of the invention, the nano high-entropy carbide has high stability, good conductivity and high chemical activity.

Description

Technical Field

[0001] The present application relates to a nano high-entropy carbide and a preparation method thereof, a high-entropy composite material, an electrocatalytic electrode and a fuel cell. Background Art

[0002] Nanocarbides exhibit remarkable mechanical properties, good electrical conductivity, and high resistance to oxidation and corrosion. High-entropy structures can further enhance the performance of nanocarbides and enable new functionalities not possible with smaller components, such as extremely high hardness and elastic modulus, improved thermal insulation, and enhanced electrochemical stability. This makes high-entropy nanocarbides (HENCs) highly anticipated for advanced applications in mechanical engineering, energy storage and conversion, and aerospace.

[0003] So far, the composition and types of metal elements in high-entropy nanocarbides are limited, which restricts the application of high-entropy nanocarbides. Summary of the Invention

[0004] The embodiments of the present application provide a nano high-entropy carbide and a preparation method thereof, 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 a first aspect, the present invention provides a method for preparing nano-high entropy carbide, comprising: providing shaped CNTs; mixing a carbon source, a plurality of metal sources, and a solvent to obtain a precursor solution; dip-coating the precursor solution on the shaped CNTs, applying an electric current to the shaped CNTs to generate Joule heat, and obtaining nano-high entropy carbide after heating, holding, and cooling, wherein the heating temperature is above 2750K and the time is 10 to 500ms, the holding temperature is 1800 to 2200K and the time is greater than 0s and less than or equal to 60s, and the cooling rate is 10 3 ~10 4 K·s -1 ; Nano high entropy carbide 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.

[0006] The present invention utilizes extremely high heating temperatures, a heat preservation phase, and an ultra-fast cooling rate to produce pure-phase nano-high-entropy carbides containing 5 to 22 metal elements. These pure-phase nano-high-entropy carbides exhibit high stability, good electrical conductivity, and high chemical activity.

[0007] In some embodiments, the holding time is 5 to 20 seconds.

[0008] In some embodiments, the precursor solution is dip-coated on the formed CNTs, and then an electric current is applied to the formed CNTs to generate Joule heat, and after heating, heat preservation and cooling, the nano high entropy carbide is obtained. The applying current includes applying a heating current and applying a heat preservation current. The applying heating current includes applying a power density of 500 to 1000 W / cm for 10 to 500 ms. 2 The current applied is greater than 0s and less than or equal to 60s, and the power density is 100 to 400W / cm 2 of current.

[0009] In some embodiments, the carbon source comprises carbon source molecules having 6 or less carbon atoms.

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

[0011] In some embodiments, the plurality of metal sources includes 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 HPtCl6 and HAuCl4.

[0013] In some embodiments, the atomic ratio of metal element concentration to carbon element 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, the shaped CNTs include any one of CNT films, CNT fibers, and CNT foams.

[0016] In some embodiments, the average spacing between adjacent CNTs in the shaped 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 a solvent; the ultrasonic dispersion power is 400 to 1000 W, and the time is 1 to 20 minutes.

[0018] In a second aspect, an embodiment of the present application provides 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 metal elements.

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

[0021] In some embodiments, the metal 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, the nano high entropy carbide comprises a general formula MC x high entropy phase carbide; wherein M includes 5 to 22 metal elements, and the metal elements include 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, the nano high entropy carbide comprises (PtWTaFeNi)C x 、(PtWTaHfCe)C x 、(VCrZnZrNbHfIrAu)C x 、(VCrMnFeCoNiNbMoTaW)C x , (MgCrMnCuZnYMoSnCeHfTaWIrPtAu)C x , (MgVCrMnFeCoNiCuZnZrYNbMoRuSnCeHfTaWIrPtAu)C x Any one of .

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

[0025] In some embodiments, based on the phase state of the nano-high entropy carbide, the content of the high entropy phase accounts for 95.0% to 100.0%.

[0026] In some embodiments, based on the phase state of the nano-high entropy carbide, the content of the high entropy phase accounts for 98.0% to 100.0%.

[0027] In some embodiments, based on the phase state of the nano-high entropy carbide, the content of the high entropy phase accounts for 99.9% to 100.0%.

[0028] In a third aspect, an embodiment of the present application provides a high-entropy composite material, comprising a molded CNTs matrix and a nano-high-entropy carbide disposed on at least a portion of the surface of the molded CNTs matrix, wherein the nano-high-entropy carbide comprises 5 to 22 metal elements, and the 5 to 22 metal elements and the carbon element form a high-entropy phase; wherein the average particle size of the nano-high-entropy carbide is 10 to 100 nm.

[0029] In a fourth aspect, an embodiment of the present application provides an electrocatalytic electrode comprising the high entropy composite material of the third aspect.

[0030] In a fifth aspect, an embodiment of the present application provides a fuel cell comprising the nano high entropy carbide of the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 A schematic diagram showing a method for preparing nano high-entropy carbides provided in some embodiments of the present application.

[0033] Figure 2 Shown are typical temperature curves in the method for preparing nano high entropy carbides provided in some embodiments of the present application.

[0034] Figure 3 The transmission electron microscope image and particle size statistics diagram of the nano high entropy carbide in Example 1 of the present application are shown, wherein a is the TEM particle size statistics diagram and b is the transmission electron microscope image.

[0035] Figure 4These are scanning electron microscope images of the carbon-based heating sources loaded with nano-high entropy carbides in Example 1 and Comparative Examples 3-6, where a is the CNTs 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 e is the hydrophobic carbon cloth in Comparative Example 6.

[0036] Figure 5 : are EDS surface scans of the nano-high entropy carbides in Examples 1-6, wherein a is the EDS surface scan of the nano-high entropy carbide in Example 1, b is the EDS surface scan of the nano-high entropy carbide in Example 2, c is the EDS surface scan of the nano-high entropy carbide in Example 3, d is the EDS surface scan of the nano-high entropy carbide in Example 4, e is the EDS surface scan of the nano-high entropy carbide in Example 5, and f is the EDS surface scan of the nano-high entropy carbide in Example 6.

[0037] Figure 6 are the XRD diffraction spectra of the nano-high entropy carbides in Examples 1-6, wherein 5-HENCs is the XRD diffraction spectrum of the nano-high entropy carbide in Example 1, 8-HENCs is the XRD diffraction spectrum of the nano-high entropy carbide in Example 3, 10-HENCs is the XRD diffraction spectrum of the nano-high entropy carbide in Example 4, 15-HENCs is the XRD diffraction spectrum of the nano-high entropy carbide in Example 5, and 22-HENCs is the XRD diffraction spectrum of the nano-high entropy carbide in Example 6.

[0038] Figure 7 HER and OER performance diagrams of nano high entropy carbide in Example 1.

[0039] Figure 8 This is the full water decomposition performance diagram of the nano high entropy carbide in Example 1.

[0040] Figure 9 This is the alcohol oxidation performance diagram of the nano high entropy carbide in Example 2, where a is alcohol oxidation, b is ethanol oxidation, and c is ethylene glycol oxidation.

[0041] In the accompanying drawings, the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION

[0042] In order to more clearly understand the above-mentioned objectives, features and advantages of the present application, the scheme of the present application will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application can also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present application, not all of the embodiments.

[0044] Below, the embodiments of the nano high entropy carbide and its preparation method, high entropy composite material, electrocatalytic electrode and fuel cell of the present application are specifically disclosed in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0045] The "ranges" disclosed herein are defined in terms of lower and upper limits, where a given range is defined by selecting a lower limit and an upper limit, and the selected lower and upper limits define the boundaries of the particular range. Ranges defined in this manner can be inclusive or exclusive of the end values ​​and can be combined arbitrarily, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, the following ranges are all contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise indicated, the numerical range "a to b" is a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

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

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

[0048] Unless otherwise specified, all steps of the present 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 may include steps (b) and (a) performed sequentially. For example, the method may further 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 may include steps (a), (c) and (b), or 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 a primary-secondary relationship.

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

[0051] In the description of the embodiments of the present application, unless otherwise specified, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0052] Unless otherwise specified, the test temperature of each parameter mentioned in this application is 25°C.

[0053] The precise control of the particle size, element types and element quantities of high-entropy nanocarbides remains a problem. These problems stem from the difficulty in achieving the controlled reactions necessary for high-entropy nanocarbides. First, the entropy-driven reaction of carbides requires extremely high growth temperatures (usually >2500K), and maintaining the high-entropy lattice structure at high temperature to room temperature (25°C) requires a very rapid cooling process. Secondly, in order to prevent the agglomeration of nanoparticles at high temperatures, the growth process is also required to be extremely short and to achieve spatial confinement effects. Finally, compared with high-entropy alloys or oxide nanoparticles, the problem of multi-component immiscibility in high-entropy nanocarbides is more prominent.

[0054] In view of this, the embodiments of the present application provide a nano high-entropy carbide and a preparation method thereof, 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 carbide

[0056] A nanometer high-entropy carbide comprises 5 to 22 metal elements, which form a high-entropy phase with carbon elements; wherein the average particle size of the nanometer high-entropy carbide is 10 to 100 nm.

[0057] The nano high entropy carbide of the embodiment of the present application has 5 to 22 metal elements, all of which are solid-dissolved with carbon to form a stable and single high entropy phase. The multiple metal elements in the high entropy phase are mixed in approximately equimolar proportions to form a stable phase with high configurational entropy. Among them, the different sizes of heterogeneous metal atoms will lead to the diversity of atomic coordination and lattice distortion, thereby producing a "cocktail effect", which significantly improves the stability, electrical conductivity and chemical activity of the nano high entropy carbide.

[0058] The nano high entropy carbide of the embodiment of the present application also has a nano effect. The synergistic effect of heterogeneous metal atoms and the nano effect can make the nano high entropy carbide have high chemical activity and high stability even under extreme conditions.

[0059] Optionally, the nano high entropy carbide includes 10 to 22 metal elements.

[0060] More optionally, the nano high entropy carbide includes 20 to 22 metal elements.

[0061] In some embodiments, the nano-high entropy carbide includes 22 metal elements.

[0062] The average particle size of the nano high entropy carbide is independently selected from any value among 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, or any range between two values.

[0063] In some embodiments, the metal 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.

[0064] The nano-high entropy carbide of the embodiment of the present application has suitable types of metal elements to enhance the "cocktail effect", thereby better improving the stability, electrical conductivity and chemical activity of the nano-high entropy carbide.

[0065] In some embodiments, the nano high entropy carbide comprises a general formula MC xhigh entropy phase carbide; wherein M includes 5 to 22 metal elements, and the metal elements include 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.

[0066] General formula MC x The M in the formula may include 5 to 22 metal elements, and x can be determined according to the valence of M so that MC x Valence balance. For example, MC x When it contains 5 metal elements, the general formula can be M1M2M3M4M5C x , where M1, M2, M3, M4, and M5 represent different metal elements; MC x When it contains 10 metal elements, the general formula can be M1M2M3M4M5M6M7M8M9M 10 C x , among which M1, M2, M3, M4, M5, M6, M7, M8, M9, M 10 Respectively represent different metal elements; MC x When it contains 20 metal 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 which 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 Respectively represent different metal elements; MC x When it contains 22 metal 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 which 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 metal elements.

[0067] In some embodiments, the Span value (D v 90-D v 10) / D v 50=0.5~10.

[0068] With a suitable range of Span values, the particle size distribution of the nano-high entropy carbide can be made more uniform, thereby making the nano-high entropy carbide have a better nano effect.

[0069] Optionally, the Span value of the nano high entropy carbide is independently selected from any value among 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, 10.0, or any range between two values.

[0070] In some embodiments, based on the phase state of the nano-high entropy carbide, the content of the high entropy phase accounts for 95.0% to 100.0%.

[0071] Optionally, the content of the high entropy phase is 98.0% to 100.0%.

[0072] More optionally, based on the phase state of the nano high-entropy carbide, the content of the high-entropy phase accounts for 99.9% to 100.0%.

[0073] In some embodiments, based on the phase state of the nano-high entropy carbide, the content of the high entropy phase accounts for 100.0%.

[0074] Nano-high entropy carbides have a single high entropy phase that can reduce the adverse effects of impurities on stability, electrical conductivity, and chemical activity.

[0075] In some embodiments, the nano high entropy carbide comprises forming CNTs loaded with a precursor and a carbon source placed in an inert atmosphere and / or a reducing atmosphere and subjected to heating, heat preservation and cooling, wherein the precursor comprises a metal source containing 5 to 22 metal elements; the heating temperature is above 2750K and the time is 10 to 500ms, the heat preservation temperature is 1800 to 2200K and the time is greater than 0s and less than or equal to 60s, and the cooling rate is 10 3 ~10 4 K·s -1 .

[0076] The embodiment of the present application first obtains an extremely high temperature of more than 2750K by instantaneous heating, which can make the precursor containing multiple metal elements disperse rapidly and carbonize better. It is then kept warm for a suitable time at 1800-2200K, which allows the diffusion of multiple metal atoms and the fusion of particles to form nanoparticles with a single-phase lattice. Finally, it is cooled at an extremely fast speed to reduce the temperature of the nano high entropy carbide to room temperature (25°C). Due to the extremely fast cooling speed, the nano high entropy carbide lacks time for phase separation, thereby reducing the generation of impurities.

[0077] Preparation method of nano high entropy carbide

[0078] A method for preparing nano high-entropy carbide comprises: providing shaped CNTs; mixing a carbon source, multiple metal sources and a solvent to obtain a precursor solution; dip-coating the precursor solution on the shaped CNTs, applying an electric current to the shaped CNTs to generate Joule heat, and obtaining nano high-entropy carbide after heating, heat preservation and cooling; the nano high-entropy carbide comprises 5 to 22 metal elements, and the 5 to 22 metal elements form a high entropy phase with the carbon element; the heating temperature is above 2750K for 10 to 500ms, the heat preservation temperature is 1800 to 2200K for more than 0s and less than or equal to 60s, and the cooling rate is 10 3 ~10 4 K·s -1 ; Among them, the average particle size of nano high entropy carbide is 10 to 100 nm.

[0079] Optionally, the insulation time is 5 to 20 seconds.

[0080] The carbon thermal shock method in related technologies usually only performs short-term thermal pulses at temperatures of 1500-2000K. Although laser scanning ablation can generate higher temperature thermal pulses at the nanosecond level, the ultra-short reaction time cannot meet the conditions for atomic diffusion to form a single phase in nano-high entropy carbides, and the introduction of carbon sources also poses challenges. Methods for synthesizing high entropy carbides, such as spark plasma sintering, electrochemical synthesis, and carbon thermal reduction, usually have relatively slow cooling rates (<10 3 K·s -1 ) or long heating times (usually exceeding 5 min), which are not conducive to the formation of single-phase nanocarbides. In addition, the carbides synthesized by these methods are usually limited to specific metal elements, which greatly limits the diversified design of nano-high-entropy carbides.

[0081] In view of this, the embodiment of the present application uses molded CNTs as a carbon-based heating source. By connecting the two ends of the molded CNTs to graphite clips as electrodes and passing an electric current, the molded CNTs generate Joule heat, so that the precursor and the carbon source can undergo a preset heating, insulation and cooling step. Since the molded CNTs have better structural stability and more excellent electrical conductivity and thermal conductivity, they can generate a large amount of Joule heat and heat themselves up rapidly, so extremely high temperatures and ultra-fast heating / cooling rates can be achieved through Joule heat. In addition, the molded CNTs can also be used as a growth substrate, and the gaps between the CNTs in the molded CNTs can play a spatial confinement role to reduce the agglomeration of nano high-entropy carbides and obtain nano-sized high-entropy carbides.

[0082] The present embodiment first achieves an extremely high temperature of over 2750K by instantaneously increasing the temperature, enabling rapid dispersion and carbonization of the precursor. At extremely high temperatures, the entropy-driven effect is significantly enhanced, promoting elemental mixing and nucleation, which in turn enables further phase purification through atomic diffusion and particle fusion.

[0083] Subsequent holding at 1800-2200K for an appropriate time facilitates further purification of the high-entropy phase. During this process, the carbide nuclei continue to mix and grow, and entropy drives the heterogeneous intermediates through atomic diffusion and particle fusion to form nanoparticles with a single-phase lattice. Due to the extremely high temperatures achieved during heating, the holding time can be effectively shortened, thereby reducing agglomeration of the nano-high-entropy carbide. This also reduces the incomplete purification of the high-entropy phase caused by too short a holding time and reduces the formation of impurity phases.

[0084] Finally, the nano-high entropy carbide is cooled at an extremely fast speed to reduce the temperature to room temperature (25°C). Due to the extremely fast cooling speed, the nano-high entropy carbide lacks time for phase separation, thereby reducing the formation of impurity phases.

[0085] The heating, insulation and cooling of the embodiments of the present application are all carried out under a preset atmosphere to reduce the influence of the 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; it can also be a mixed atmosphere of an inactive atmosphere and a reducing atmosphere, such as a mixed gas of hydrogen and argon.

[0086] Optionally, the elevated temperature is independently selected from any value among 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, 5000K or any range between two thereof.

[0087] Optionally, the heating time 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 , 270ms, 280ms, 290ms, 300ms, 310ms, 320ms, 330ms, 340ms, 350ms, 360ms, 370ms, 380ms, 390ms, 400ms, 410ms, 420ms, 430ms, 440ms, 450ms, 460ms, 470ms, 480ms, 490ms, 500ms or any range between any two of them.

[0088] Optionally, the insulation temperature is independently selected from any value among 1800K, 1850K, 1900K, 1950K, 2000K, 2050K, 2100K, 2150K, 2200K, or any range between two values.

[0089] Optionally, the holding time 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, 31s, 32s, Any value among 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 of them.

[0090] In some embodiments, the precursor solution is dip-coated on the formed CNTs, and then an electric current is applied to the formed CNTs to generate Joule heat, and after heating, heat preservation and cooling, the nano high entropy carbide is obtained. The applying current includes applying a heating current and applying a heat preservation current. The applying heating current includes applying a power density of 500 to 1000 W / cm for 10 to 500 ms. 2 The current applied is greater than 0s and less than or equal to 60s, and the power density is 100 to 400W / cm 2 of current.

[0091] In the embodiment of the present application, the molded CNTs are used as a carbon-based heating source. By connecting the two ends of the molded CNTs to graphite clips as electrodes and passing current, the molded CNTs generate Joule heat, so that the precursor and the carbon source can go through the preset heating, insulation and cooling steps. Since the molded CNTs have better structural stability and better electrical and thermal conductivity, they can generate a lot of Joule heat and heat themselves up rapidly, so extremely high temperatures and ultra-fast heating / cooling rates can be achieved through Joule heat. Among them, the power density of 500 to 1000 W / cm is applied for 10 to 500 ms. 2 The current can quickly heat the formed CNTs to above 2750K; then apply a power density of 100-400W / cm3 for more than 0s and less than or equal to 60s. 2 The current can keep the formed CNTs at 1800-2200K for 0-60s; finally, the applied current is removed and the formed CNTs will be heated to 10 3 ~10 4 K·s -1 Cooling rate down to room temperature.

[0092] Optionally, the power density of the heating current is independently selected from 500W / cm 2 、550W / cm 2 , 600W / 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 between or any range of values ​​between them.

[0093] 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, ms, 270ms, 280ms, 290ms, 300ms, 310ms, 320ms, 330ms, 340ms, 350ms, 360ms, 370ms, 380ms, 390ms, 400ms, 410ms, 420ms, 430ms, 440ms, 450ms, 460ms, 470ms, 480ms, 490ms, 500ms, or any range between them.

[0094] Optionally, the power density of the holding current is independently selected from 100 W / cm 2 , 150W / cm 2 , 200W / cm 2 , 250W / cm 2 , 300W / cm 2 、350W / cm 2 , 400W / cm 2 Any value in between or any range of values ​​between them.

[0095] Optionally, the application time of the holding 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, 31s , 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 any range between them.

[0096] In some embodiments, the interval between applying the heating current and applying the holding current is t, 0≤t≤30s.

[0097] In the embodiment of the present application, the heat-maintaining current may be applied immediately after the heating current is applied, or it may be applied after a certain period of time.

[0098] In some embodiments, the step of dip-coating the precursor solution on the formed CNTs includes dip-coating the precursor solution on the formed CNTs 1 to 10 times, and drying in air at 60° C. for 1 to 10 minutes after each dip-coating.

[0099] In some embodiments, the plurality of metal sources includes one or more of metal chlorides and metal complexes.

[0100] In some embodiments, the carbon source comprises carbon source molecules having 6 or less carbon atoms.

[0101] Optionally, the number of carbon atoms in the carbon source molecule can be 1, 2, 3, 4, 5, 6, or a range consisting of any of the above values.

[0102] Optionally, the carbon source includes one or more of urea, methane, alanine and glucose.

[0103] Small molecular carbon sources can be more easily decomposed to form nuclei with metal elements.

[0104] 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.

[0105] In some embodiments, the atomic ratio of metal element concentration to carbon element in the precursor solution is (0.2-5):1.

[0106] Metal elements and carbon elements with a suitable concentration ratio can reduce the possibility of precipitation of metal elements and / or carbon elements, thereby reducing the possibility of formation of mixed phases between precipitated elements and / or between precipitated elements and non-precipitated elements, thereby improving the purity of the nano high entropy carbide single phase.

[0107] Optionally, the ratio of the metal element concentration to the 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, 2.5:1. :1, 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 range between them.

[0108] In some embodiments, the total metal ion concentration in the precursor solution is 0.01-0.8M.

[0109] 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, 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 , 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, 0.8M or any range between any two of them.

[0110] In some embodiments, the shaped CNTs include any one of CNT films, CNT fibers, and CNT foams.

[0111] 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 containing multiple metal elements, and the resulting carbide particles are larger.

[0112] The CNT film in the embodiments of this application is a flexible film formed by randomly interwoven CNTs; CNT fibers are continuous fibers produced by wet spinning or direct spinning; and CNT foam has a three-dimensional porous, lightweight structure. Molded CNTs with a suitable structure can generate Joule heat when an electric current is applied, causing them to rapidly heat up to extremely high temperatures, and then rapidly cool down when the current is removed. Furthermore, the spaces between the CNTs in the molded CNTs act as spatial confinement, reducing the agglomeration of nano-high-entropy carbides and resulting in nano-sized high-entropy carbides.

[0113] In some embodiments, the average spacing between adjacent CNTs in the shaped CNTs is 10-20 nm.

[0114] The average spacing between adjacent CNTs within a suitable range can better play a role in spatial confinement, thereby obtaining high-entropy carbides with nanometer dimensions.

[0115] Optionally, the average spacing between adjacent CNTs is independently selected from any value among 10 nm, 11 m, 12 m, 13 m, 14 m, 15 m, 16 m, 17 m, 18 m, 19, 20 nm, or any range therebetween.

[0116] In some embodiments, the method for preparing shaped CNTs includes ultrasonically dispersing commercial CNTs, disordered CNTs synthesized by chemical vapor deposition, arrayed CNTs, and a solvent, wherein the ultrasonic dispersion power is 400 to 1000 W and the time is 1 to 20 minutes.

[0117] Mixed molding of CNTs with different structures and different synthesis methods can enable the molded CNTs to better achieve extremely high temperatures and ultra-fast heating / cooling rates through Joule heat; at the same time, it can also enable the molded CNTs to have better spatial confinement.

[0118] In some embodiments, after ultrasonically dispersing commercial CNTs, disordered CNTs synthesized by chemical vapor deposition, arrayed CNTs, and a solvent, a filtration process is also performed 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: a high-power probe is used to ultrasonically disperse 10 to 50 mg of CNTs into 100 to 500 mL of ethanol at 400 to 1000 W, and the ultrasonic time is 1 to 20 minutes. The suspension is then immediately transferred to a filtration device, and a CNT film is formed on the filter paper by vacuum filtration.

[0119] In some embodiments, the formed CNTs are further subjected to pore formation treatment, wherein the diameter of the pores is 10 to 500 μm, so as to allow gas to be discharged.

[0120] Example

[0121] The following examples describe the present disclosure in more detail. These examples are intended to be illustrative only, as various modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by mass, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing. The instruments used in the examples are commercially available.

[0122] Example 1

[0123] Preparation of CNTs formed by carbon-based heating sources

[0124] Single-walled carbon nanotubes (SACNTs) were prepared on silicon wafers by low-pressure chemical vapor deposition (LPCVD) using acetylene gas as a precursor and metallic iron nanoparticles as a catalyst. 20 mg of SACNTs were placed in 250 ml of ethanol and dispersed at 600 W for 5 minutes using high-power probe ultrasound (SCIENTZ-950E). The suspension was then immediately transferred to a suction filter and vacuum filtered to form a carbon nanotube film (CNTs film) with a diameter of 40 mm on filter paper. After sufficient drying in air, the CNTs film was cut into rectangular shapes and micron-sized holes were drilled using a direct laser writer (wavelength 1064 nm). The holes had a diameter of 40 μm and a spacing of 800 μm to effectively release bubbles generated during the organic waste incineration (OWS) process.

[0125] Preparation of Nano-High Entropy Carbides

[0126] The metal sources H2PtCl6, WCl6, TaCl5, FeCl3, NiCl2 and the 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 0.05M; the precursor solution was then dip-coated onto a carbon nanotube film (CNTs film) and dried in air at 60°C for 2 minutes; thereafter, the CNTs film loaded with the precursor was inserted into a circuit with a graphite clip as an electrode and Joule heated in a mixed atmosphere of 10% hydrogen (H2) and 90% argon (Ar). After heating, insulation and cooling, a high-entropy composite material was obtained, which included a molded CNTs matrix and a single-crystal nano-high-entropy carbide (PtWTaFeNi)C disposed on the surface of the molded CNTs matrix. x ,(PtWTaFeNi)C x The average particle size is 20nm, the purity is 100%, and the heating process includes applying a power density of 800W / cm 2The current lasted for 50ms, causing the CNTs film to heat up to 2750K. The holding process included applying a power density of 240W / cm 2 The current was applied for 5 seconds, so that the CNTs film was kept at 2000K for 5 seconds. The cooling process included removing the applied current, so that the CNTs film was cooled ultra-fast at a rate of 7800K / s.

[0127] The temperature of the CNTs film was measured in situ using an infrared thermometer (Optrics, PI640&PI05M).

[0128] Performance Testing

[0129] Electrochemical measurements were performed using a CHI 660e / 760e electrochemical workstation at room temperature using a standard three-electrode method. The prepared high-entropy composite material was used directly as the working electrode, Hg / HgO as the reference electrode, Pt as the counter electrode, and the electrolyte was 1 M KOH. The temperature was room temperature or 60°C. The polarization curves were measured at 5 mV·s. -1 The scan rate was measured with 85% compensation. No additional compensation was used for the stability test. To maintain the pH and level of the electrolyte during the long-term test, deionized water was continuously added via a micro syringe.

[0130] Figure 7-Figure 8 shows that (PtWTaFeNi)C x Hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and overall water splitting (OWS) at high current density. x It exhibits a very stable hydrogen evolution reaction (HER) at 2000 / 5000mA·cm -2 The potential variation is only 4.5% / 7.1% within 600 / 320 h, and the overall water splitting (OWS) cell voltage under industrial conditions is only 1.63 V (3000 mA cm -2 ). In addition, the synthesized (PtWTaFeNi)C x After high-temperature growth, they are firmly attached to the conductive CNTs film matrix and can therefore be directly used as HER and OER electrodes.

[0131] Figure 5 and Figure 6 (PtWTaFeNi)C x Energy dispersive spectroscopy (EDS) images and X-ray diffraction (XRD) images. As can be seen from the figure, (PtWTaFeNi)C x It is a pure single-phase structure.

[0132] Examples 2-6

[0133] The experimental steps and performance tests are the same as those in Example 1, with the only difference being the different metal sources, heating, insulation, and cooling parameters in the preparation of nano-high entropy carbides. See Tables 1 and 2 for details.

[0134] Comparative Example 1

[0135] The experimental steps and performance tests were the same as those in Example 1, except that heat preservation was not performed during the preparation of the nano-high entropy carbide. For details, see Tables 1 and 2.

[0136] Comparative Example 2

[0137] The experimental steps and performance tests were the same as those in Example 6, with the only difference being that heat preservation was not performed during the preparation of the nano-high entropy carbide. For details, see Tables 1 and 2.

[0138] Table 1

[0139]

[0140]

[0141] Table 2

[0142]

[0143]

[0144] As shown in Table 1, the metal elements and carbon elements in Examples 1-6 can be obtained into pure nano-high-entropy carbides after heating, holding, and cooling. However, in Comparative Example 1, which does not include a holding treatment, the carbide nuclei formed during the heating process cannot continue to mix and grow, resulting in a large amount of impurities. Comparative Example 2 differs from Example 6 only in that it does not include a holding treatment. Since Comparative Example 2 contains 22 metal elements, it produces a large number of impurity carbide phases, which are less than the 22 metal elements.

[0145] Comparative Examples 3-6

[0146] The experimental steps and performance tests were the same as those in Example 1, with the only difference being the carbon-based heating source. See Table 3 for details.

[0147] Table 3

[0148] Carbon-based heating source Heating temperature Average particle size of nano high entropy carbide Example 1 CNTs film 2750K 20nm Comparative Example 3 Hydrophilic carbon paper 2500K 50nm Comparative Example 4 Hydrophobic carbon paper 2500K 200nm Comparative Example 5 Hydrophilic carbon cloth 2400K 90nm Comparative Example 6 Hydrophobic carbon cloth 2400K 300nm

[0149] Figure 4 The scanning electron microscope images of the products in Example 1 and Comparative Examples 3-6 are shown in Table 3 and Figure 4It can be seen that the use of CNTs film 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 multiple metal elements and carbon elements form a high-entropy phase.

[0150] like Figure 1 As shown, in the embodiment of the present application, a large voltage pulse is applied to the CNTs film loaded with the precursor in an atmosphere of H2 / Ar mixed gas or H2 or Ar or N2, and its temperature is instantaneously increased to 2750K by Joule heating, with a heating rate of 103~105K·s -1 . In this step, the metal precursor is rapidly dispersed and carbonized. At high temperatures, the entropy-driven effect is significantly enhanced, promoting element mixing and assisting nucleation, which can further achieve phase purification through atomic diffusion and particle fusion. Secondly, through Joule self-heating, the preset time is maintained at 1800-2200K, which helps to further purify the nano high-entropy carbide phase. In this step, the carbide nuclei will continue to mix and grow, and entropy will drive the inhomogeneous intermediates to form nanoparticles with a single-phase lattice through atomic diffusion and particle fusion. Due to the ultra-high temperature pulse in the thermal pulse step, the stable growth time can be effectively shortened, effectively avoiding the agglomeration of nano high-entropy carbide particles. Finally, after removing the applied voltage, an ultra-fast cooling process is immediately achieved, with a cooling rate of 103-104K·s -1 , due to the lack of phase separation time, the high entropy phase formed at high temperature will be maintained to room temperature.

[0151] Figure 2 This is a typical temperature curve of the embodiment of the present application, Figure 2 It can be seen that the embodiment of the present application goes through three processes: heating, stable growth and cooling.

[0152] Figure 3 This is 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.

[0153] Figure 9 The alcohol oxidation performance diagram of the nano high entropy carbide in Example 2 shows that the mass activity of the nano high entropy carbide in Example 2 for methanol oxidation reaction (MOR), ethanol oxidation reaction (EOR) and ethylene glycol oxidation reaction (EGOR) is 12.02 A·mg -1 Pt 、3.97A·mg -1 Pt and 23.45A·mg -1 Pt These remarkable electrocatalytic capabilities are beyond the reach of conventional electrocatalysts or minority-element nanocarbons.

[0154] The above description is only a specific embodiment of the present application. Those skilled in the art will clearly understand that for the convenience and brevity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the scope of protection of the present application.

Claims

1. A method for preparing nano high entropy carbide, characterized in that: include: Providing shaped CNTs; A carbon source, a plurality of metal sources and a solvent are mixed to obtain a precursor solution; The precursor solution is dip-coated on the formed CNTs, and then an electric current is applied to the formed CNTs to generate Joule heat. After heating, heat preservation and cooling, nano high entropy carbide is obtained, wherein the heating temperature is above 2750K and the time is 10 to 500ms, the heat preservation temperature is 1800 to 2200K and the time is greater than 0s and less than or equal to 60s, and the cooling speed is 10 3 ~10 4 K·s -1 ; The nano-high entropy carbide comprises 5 to 22 metal elements, and the 5 to 22 metal elements and carbon element 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 insulation time is 5 to 20 seconds.

3. The preparation method according to claim 1, characterized in that In the step of dip-coating the precursor solution on the formed CNTs, applying current to the formed CNTs to generate Joule heat, and obtaining nano high entropy carbide after heating, heat preservation and cooling, The applying current includes applying a heating current and applying a heat preservation current, wherein the applying heating current includes applying a power density of 500 to 1000 W / cm for 10 to 500 ms. 2 The current of the holding current includes applying a current greater than 0s and less than or equal to 60s with a power density of 100 to 400W / cm 2 of current.

4. The preparation method according to claim 1, characterized in that The carbon source includes a carbon source molecule having a carbon number less than or equal to 6; Optionally, the carbon source includes one or more of urea, methane, alanine and glucose.

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

6. The preparation method according to claim 1, characterized in that The atomic ratio of metal element concentration to carbon element 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.

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

8. The preparation method according to claim 1, characterized in that The method for preparing the molded CNTs comprises: The commercial CNTs, disordered CNTs synthesized by chemical vapor deposition, arrayed CNTs and solvents were ultrasonically dispersed to obtain the obtained products. The power of the ultrasonic dispersion is 400-1000W, and the time is 1-20 minutes.

9. A nano high entropy carbide, characterized in that: The nano high entropy carbide comprises 5 to 22 metal elements, and the 5 to 22 metal elements and carbon element form a high entropy phase; Wherein, the average particle size of the nano high entropy carbide is 10 to 100 nm.

10. The nano high entropy carbide according to claim 9, characterized in that: The nano high entropy carbide comprises 10 to 22 metal elements; and / or, The nano high entropy carbide includes 20 to 22 metal elements.

11. The nano high entropy carbide according to claim 9, characterized in that: The metal 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.

12. The nano high entropy carbide according to claim 9, characterized in that: The nano high entropy carbide includes a general formula of MC x High entropy phase carbides; Among them, M includes 5 to 22 metal elements, and the metal elements include 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.

13. The nano high entropy carbide according to claim 9, 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 .

14. The nano high entropy carbide according to claim 9, characterized in that: The Span value (D v 90-D v 10) / D v 50=0.5~10.

15. The nano high entropy carbide according to claim 9, characterized in that: Based on the phase state of the nano high entropy carbide, the content of the high entropy phase accounts for 95.0% to 100.0%; and / or, Based on the phase state of the nano high entropy carbide, the content of the high entropy phase accounts for 98.0% to 100.0%; and / or, Based on the phase state of the nano high-entropy carbide, the content of the high-entropy phase accounts for 99.9% to 100.0%.

16. A high entropy composite material, characterized in that The invention comprises a formed CNTs matrix and a nanometer high entropy carbide provided on at least a portion of the surface of the formed CNTs matrix, wherein the nanometer high entropy carbide comprises 5 to 22 metal elements, and the 5 to 22 metal elements and the carbon element form a high entropy phase; Wherein, the average particle size of the nano high entropy carbide is 10 to 100 nm.

17. An electrocatalytic electrode, characterized in that Including the high entropy composite material according to claim 16.

18. A fuel cell, characterized in that: The invention comprises the nano high entropy carbide according to any one of claims 9 to 15.

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