Precious metal and refractory multi-principal component substrate combined high-entropy alloy catalyst, preparation method and acidic OER application

Abstract

The invention relates to a noble metal and refractory multi-principal component substrate combined high-entropy alloy catalyst, a preparation method and acidic OER application. The catalyst is a high-entropy alloy formed by a refractory metal component A and a noble metal active component B, the component expression is AxBy, A is selected from multiple of Ta, Nb, Hf, Zr, Ti, W and Mo, and B is selected from at least one of Ir, Os and Ru. The structure of a precursor is regulated and controlled through physical metallurgy alloying, a unique structure that a dendritic refractory metal component supports a granular active component is obtained through a dealloying technology, and the catalyst can be directly used for an acidic OER catalyst, has activity and stability under the working condition of high current density, has the characteristics of low precious metal consumption and capability of being prepared in a large scale, and is suitable for industrial production. The method has the practical application potential as a PEM electrolytic cell catalyst.

Description

Technical Field

[0001] The present invention relates to the application field of acidic PEM (Proton Exchange Membrane) catalysts, and in particular to a high-entropy alloy catalyst combining a noble metal with a refractory multi-principal element substrate, a preparation method, and acidic OER (Oxygen Evolution Reaction) applications. Background Art

[0002] Since the acidic environment has high requirements for catalyst stability and the overall water electrolysis reaction depends on the energy barrier of the anode OER, there is a contradictory relationship between the activity and stability of the catalyst. How to balance the activity and stability of catalytic materials is the current focus of research on acidic OER catalysts.

[0003] In the acidic water electrolysis process, due to the strong acidity, strong oxidizing properties and slow kinetics of the catalytic process, only platinum group noble metals currently exhibit good comprehensive catalytic performance. However, the high price and scarce reserves of noble metals limit their prospects for industrialization. In recent years, domestic and foreign scholars have achieved a joint improvement in the activity and durability of OER catalysts by regulating the electronic structure and lattice. From the perspective of physical metallurgy, alloying is the most effective method to produce electronic structure effects and lattice strain effects. The design concept of multi-principal element high-entropy alloys based on the "mixed entropy" effect provides a broader compositional space for alloying to regulate the intrinsic structure of the catalyst. High-entropy alloys, with their advantages such as strong electronic structure effects, strong lattice strain effects, and high chemical structure stability, are expected to achieve OER catalytic performance with both activity and stability.

[0004] At the same time, traditional nanoparticle catalysts still have many disadvantages in industrial applications: since nanoparticle catalysts do not have a self-supporting structure and are generally in powder form, a binder is needed to coat the catalytic material onto a substrate (glassy carbon electrode, carbon cloth, etc.) for use. Traditional nanoparticle catalyst substrate support materials are easily peeled off from the active substance under high current density or strong acidic environment. The carbon material serving as the substrate will be oxidized and corroded and dissolved, resulting in the active substance having no carrier support, and the electrocatalytic performance is seriously deteriorated. In addition, the coating process is relatively time-consuming and difficult to apply on a large scale. Summary of the Invention

[0005] The present invention aims to produce an acidic OER catalyst composed of a noble metal and a refractory multi-principal element substrate through physical metallurgical process control and selective dealloying technology. This catalyst, while reducing the amount of noble metal required, is adaptable to the acidic, high-current-density reaction environment of PEM water electrolysis, meeting the application requirements of acidic water electrolysis for hydrogen production under industrial high-current-density conditions for long-term, efficient, and stable service. Furthermore, the material preparation method is simple and easy to operate, facilitating the large-scale application of PEM water electrolysis technology.

[0006] In a first aspect, an embodiment of the present invention provides a high entropy alloy catalyst, wherein the catalyst is composed of a high entropy alloy composed of a refractory metal component A and a noble metal active component B; the composition expression of the high entropy alloy is A x B y , wherein A is composed of multiple elements selected from Ta, Nb, Hf, Zr, Ti, W, and Mo, B is at least one element selected from Ir, Os, and Ru, and x and y are atomic percentages of the elements, satisfying 95≤x≤99, 1≤y≤5, and x+y=100.

[0007] According to a preferred embodiment of the first aspect, A is composed of Ta, Nb, Hf, Zr and Ti, B is Ir, and the composition expression of the high entropy alloy is (TaNbHfZrTi) x Ir y .

[0008] According to a preferred embodiment of the first aspect, A is composed of Ta, Nb, Hf, Zr and Ti, B is composed of Ir and Ru, and the composition expression of the high entropy alloy is (TaNbHfZrTi) x (IrRu) y .

[0009] According to a preferred embodiment of the first aspect, the high entropy alloy has a BCC structure, which is mainly composed of the refractory metal component A, wherein the noble metal active component B is dispersed in the BCC structure.

[0010] According to a preferred embodiment of the first aspect, the high-entropy alloy forms a dendritic support structure of the refractory metal component A under dealloying selective corrosion conditions, so as to increase the specific surface area of the precious metal active component B while serving as the substrate of the precious metal active component B; and the precious metal active component B is oxidized during the dealloying process to form spherical particles of IrO2 and RuO2 with a particle size of 100~300nm dispersed on the support structure.

[0011] In a second aspect, an embodiment of the present invention provides a method for preparing a high entropy alloy catalyst, comprising the following steps: (a) preparing ingredients: placing the raw materials of the high entropy alloy into ultrapure water and anhydrous alcohol for ultrasonic cleaning multiple times, and after drying, accurately weighing the raw materials according to the composition of the high entropy alloy to prepare the raw materials, wherein the composition expression of the high entropy alloy is A x B y , wherein A is composed of multiple elements selected from Ta, Nb, Hf, Zr, Ti, W, and Mo, B is at least one element selected from Ir, Os, and Ru, x and y are atomic percentages of the elements, satisfying 95≤x≤99, 1≤y≤5, and x+y=100; (b) smelting and negative pressure suction casting: smelting the raw materials obtained in step (a) in a non-consumable vacuum arc furnace to obtain a molten alloy with uniform composition; injecting the molten alloy into a water-cooled copper mold by a negative pressure suction casting process and cooling and solidifying it to form a high-entropy alloy precursor in the shape of a rod or plate; (c) annealing: annealing the precursor obtained in step (b) to achieve microstructure homogenization and control; (d) dealloying: placing the precursor obtained in step (c) in an acidic solution for dealloying to obtain a self-supporting catalyst.

[0012] According to a preferred embodiment of the second aspect, in step (b), the smelting current is ≥250 A, and the smelting temperature is ≥3000°C.

[0013] According to a preferred embodiment of the second aspect, in step (c), the annealing temperature is 1000-1500° C., and the holding time is 3-5 h.

[0014] According to a preferred embodiment of the second aspect, in step (d), the acidic solution is 0.5 M HF, and the dealloying time is 0 to 5 days.

[0015] In a third aspect, an embodiment of the present invention provides a catalyst obtained by the preparation method according to any one of the second aspects.

[0016] In a fourth aspect, an embodiment of the present invention provides a use of the catalyst according to the third aspect in acidic OER.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The high-entropy alloy material developed in the present invention has a flexible and adjustable structure and a self-supporting structure. It innovatively realizes the integrated preparation of precious metal components directly together with the refractory metal support substrate, and forms a unique structure of dendritic refractory components supporting granular active components. It can be directly used as an acidic OER catalyst and has both activity and stability under high current density working conditions. At the same time, the material has the characteristics of low precious metal usage and can be prepared in large quantities, and has practical application potential as a PEM electrolyzer catalyst.

[0019] (2) This invention innovatively proposes a strengthening strategy based on physical metallurgy and multi-principal element alloying to regulate electronic structure and lattice strain, and develops a design and preparation method for a self-supporting high-entropy alloy catalyst with excellent acidic OER activity and stability, providing a new approach to solving the contradiction between the inverted activity and stability of traditional acidic OER catalysts.

[0020] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate one or more embodiments of the invention and, together with the description, serve to explain the principles of the invention and to enable one skilled in the relevant art to make and use the invention.

[0022] Figure 1 (TaNbHfZrTi) prepared in Example 1 95 XRD pattern of Ir5 high-entropy alloy precursor.

[0023] Figure 2 (TaNbHfZrTi) prepared in Example 1 95 SEM image of Ir5 high-entropy alloy precursor.

[0024] Figure 3 (TaNbHfZrTi) prepared in Example 2 99 SEM image of (IrRu)1 high-entropy alloy precursor.

[0025] Figure 4 This is a SEM image of the (TaNbHfZrTi)IrO2 catalyst prepared in Example 3.

[0026] Figure 5 This is the SEM image of the (TaNbHfZrTi) (IrO2RuO2) catalyst prepared in Example 4.

[0027] Figure 6 (TaNbHfZrTi) prepared in Example 1 95 Comparative linear sweep voltammetry curves of the Ir5 high entropy alloy precursor and the (TaNbHfZrTi)IrO2 catalyst prepared in Example 3 in 0.5 M H2SO4 electrolyte.

[0028] Figure 7 (TaNbHfZrTi) prepared in Example 1 95Comparison of Tafel slopes of the Ir5 high entropy alloy precursor and the (TaNbHfZrTi)IrO2 catalyst prepared in Example 3 in 0.5 M H2SO4 electrolyte.

[0029] Figure 8 The (TaNbHfZrTi) IrO2 catalyst prepared in Example 3 was tested at a current density of 1 A cm -2 Voltage-time curve under different conditions. DETAILED DESCRIPTION

[0030] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments may be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, the description of these embodiments is intended to make the present disclosure more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a deeper understanding of the embodiments of the present invention.

[0031] (Composition design of catalytic electrode)

[0032] An embodiment of the present invention relates to a catalyst, which is an alloy, specifically a high entropy alloy. The high entropy alloy is designed to be composed of a refractory metal component A and a noble metal active component B. The high entropy alloy has a BCC structure, which is mainly composed of a refractory metal component A, wherein the noble metal active component B is dispersed in the BCC structure. Among them, the BCC structure formed by the refractory metal component A has good conductivity and supporting effect, excellent corrosion resistance and thermal stability, and can protect the noble metal active component B under high current conditions, thereby extending the service life of the catalyst. By removing part of the BCC phase through dealloying treatment to form a dendritic structure, more catalytic active sites can be added, and the specific surface area of the noble metal active component B can be increased. The noble metal active component B, as the key active center of the catalytic reaction, has high catalytic activity, can promote the reaction and improve the catalytic efficiency.

[0033] In terms of composition design, A x B y represents the overall composition of the high-entropy alloy, where A is composed of multiple elements selected from Ta, Nb, Hf, Zr, Ti, W, and Mo, B is at least one element selected from Ir, Os, and Ru, and x and y are the atomic percentages of the elements, satisfying 95≤x≤99, 1≤y≤5, and x+y=100.

[0034] As a further optimization of the composition design, A is composed of Ta, Nb, Hf, Zr and Ti, B is Ir, and the composition expression of the high entropy alloy is (TaNbHfZrTi) x Ir y That is, the BCC structure is mainly composed of refractory metal components A formed by Ta, Nb, Hf, Zr and Ti, and the noble metal active components B dispersed in the BCC structure are mainly composed of Ir. Under the conditions of dealloying selective corrosion, this high-entropy alloy forms a dendritic support structure of refractory metal components A (Ta, Nb, Hf, Zr, Ti). The noble metal active component B (Ir) is oxidized during the dealloying process to form IrO2 spherical particles with a particle size of 300-500nm dispersed on the support structure. This dendritic structure can significantly enhance the bonding strength between the particles and the substrate, and construct a hierarchical pore network in three-dimensional space to achieve efficient electrolyte penetration and rapid electron / proton transport.

[0035] As a further optimization of the composition design, A is composed of Ta, Nb, Hf, Zr and Ti, and B is composed of Ir and Ru. The composition expression of the high entropy alloy is (TaNbHfZrTi) x (IrRu) y . That is, the BCC structure is mainly composed of refractory metal components A formed by Ta, Nb, Hf, Zr and Ti, and the noble metal active components B dispersed in the BCC structure are mainly composed of Ir and Ru. The high entropy alloy forms a dendritic support structure of refractory metal components A (Ta, Nb, Hf, Zr, Ti) under dealloying selective corrosion conditions. The noble metal active components B (Ir, Ru) are oxidized during the dealloying process to form spherical particles of IrO2 and RuO2 with a particle size of 100~300nm dispersed on the support structure. The synergistic effect of the dual-phase oxide has the chemical characteristics of enriching active sites, and jointly reduces the reaction energy barrier of OER through local charge redistribution and lattice strain. In this way, the high entropy alloy catalyst of the present invention forms a composite structure of a self-supporting dendritic substrate and nano-oxide particles, taking into account structural stability, active material utilization and economy, and providing an effective technical approach for the development of acidic OER catalysts.

[0036] (Preparation of Catalytic Electrode)

[0037] In general, the catalysts described in the embodiments of the present invention are prepared using a combination of physical metallurgical process control and dealloying technology. Physical metallurgical process control involves steps such as smelting, solidification, and heat treatment of the alloy. This process can adjust parameters such as the alloy's microstructure, grain size, phase transitions, and lattice defects, laying the foundation for further dealloying. Dealloying technology selectively removes certain components or phase structures from an alloy, thereby adjusting the alloy's chemical composition and properties.

[0038] The steps for preparing the catalyst involved in the embodiment of the present invention are as follows:

[0039] (a) Ingredients

[0040] The raw materials of high entropy alloy (ensuring that the purity of the raw materials reaches or exceeds 99.5 wt%) are respectively placed in ultrapure water and anhydrous alcohol for multiple ultrasonic cleanings, and after drying, the raw materials are accurately weighed according to the composition of the high entropy alloy to prepare the raw materials. The composition expression of the high entropy alloy is A x B y , wherein A is composed of multiple elements selected from Ta, Nb, Hf, Zr, Ti, W, and Mo, B is at least one element selected from Ir, Os, and Ru, and x and y are atomic percentages of the elements, satisfying 95≤x≤99, 1≤y≤5, and x+y=100.

[0041] (b) Melting and vacuum casting

[0042] The raw materials obtained in step (a) are melted in a non-consumable vacuum arc furnace to obtain a molten alloy with uniform composition; the molten alloy is poured into a water-cooled copper mold by a negative pressure suction casting process and cooled and solidified to form a high-entropy alloy precursor in the shape of a rod or plate.

[0043] Specifically, under the protection of a high-purity Ar atmosphere, the ingredients in step (a) are smelted in a non-consumable vacuum arc furnace. The smelting current is set to not less than 250A, the smelting temperature is set to not less than 3000°C, and the smelting is repeated for not less than 5 times to ensure that each element is fully and evenly diffused in the master alloy ingot to obtain a molten alloy with uniform composition. The molten alloy is then infiltrated into a water-cooled copper mold using a negative pressure suction casting method. Under the action of negative pressure, the molten alloy quickly fills the cavity of the copper mold and is rapidly cooled in the copper mold. During the cooling process, the alloy melt gradually solidifies to obtain a high-entropy alloy precursor in the form of a rod or plate.

[0044] (c) Annealing

[0045] The precursor obtained in step (b) is annealed to achieve tissue homogenization control.

[0046] Specifically, the precursor obtained in step (b) is annealed in a high-temperature furnace at 1000-1500°C for 3-5 hours. This annealing treatment homogenizes the precursor structure, thereby reducing hardness and improving machinability; lowering residual stress, stabilizing dimensions, and reducing deformation and cracking tendencies; and simultaneously refining grains, adjusting the structure, and eliminating structural defects. This further homogenizes the material structure and composition, improving the overall performance and service life of the alloy.

[0047] (d) Dealloying

[0048] The annealed precursor obtained in step (c) is placed in an acidic solution for dealloying to obtain a self-supporting catalyst.

[0049] Specifically, the precursor obtained in step (c) is placed in a 0.5 M HF acidic solution for dealloying for 0 to 5 days. By regulating the solution concentration and time, a dendritic porous high-entropy alloy catalyst can be obtained. This dendritic porous structure is conducive to increasing the active surface area and improving the proton or electron transport performance, thereby improving the catalytic performance of the catalyst.

[0050] In order to better understand the present invention, the present invention is further described below based on detailed examples, but the present invention is not limited to these examples.

[0051] (Example 1)

[0052] According to the nominal composition of high entropy alloy (TaNbHfZrTi) 95 Ir5, alloy raw materials (purity above 99.5 wt%) were prepared, and a total of 10 g of alloy was converted into corresponding mass according to atomic percentage and accurately weighed with an error control of ±0.002 g; the atomic percentages of Ta, Nb, Hf, Zr, and Ti were 1:1:1:1:1; the weighed raw materials were melted in a non-consumable vacuum arc furnace under high-purity Ar atmosphere at a melting current of 250 A for 5 min, and the melting was repeated 6 times to ensure uniform composition of the master alloy ingot; the molten alloy was then infiltrated into a water-cooled copper mold by negative pressure suction casting to obtain a rod-shaped (TaNbHfZrTi) 95 Ir5 high entropy alloy precursor.

[0053] Figure 1 (TaNbHfZrTi) prepared in Example 1 95 The XRD pattern of the Ir5 high entropy alloy precursor shows that it has a BCC structure. Combined with EDS element analysis, it is found that the BCC structure is mainly composed of Ta, Nb, Hf, Zr, and Ti elements. Figure 2 (TaNbHfZrTi) prepared in Example 1 95 The SEM image of the Ir5 high entropy alloy precursor shows that it has a two-phase structure, namely a BCC phase rich in Ta, Nb, Hf, Zr, and Ti, and an active component phase rich in Zr and Ir.

[0054] (Example 2)

[0055] Design nominal composition (TaNbHfZrTi) 99The (IrRu)1 high-entropy alloy is prepared by mixing the raw materials (purity of 99.5 wt% or more) and accurately weighing 10 g of the alloy according to the atomic percentage, with an error of ±0.002 g. The atomic percentages of Fe, Nb, Hf, Zr, and Ti are 1:1:1:1:1, and the atomic percentages of Ir and Ru are 1:1. The master alloy is then melted using a high-purity argon atmosphere vacuum arc melting method to obtain a master alloy button ingot. The melting process is repeated at least five times to ensure uniform composition. The (TaNbHfZrTi) ingot is then obtained using a water-cooled copper mold suction casting method in the form of a bar. 99 (IrRu)1 high entropy alloy precursor.

[0056] Figure 3 (TaNbHfZrTi) prepared in Example 2 99 SEM images of (IrRu)1 high-entropy alloy precursors show that both have a single-phase structure, namely a BCC phase rich in Ta, Nb, Hf, Zr, and Ti. Due to the low content of active elements, no obvious phase distinction is formed.

[0057] (Example 3)

[0058] The (TaNbHfZrTi) prepared in Example 1 95 The Ir5 high-entropy alloy precursor was annealed at 1200°C for 4 hours. The annealed precursor was then chemically dealloyed in a 0.5M HF solution at room temperature for 10 hours. The precursor was then ultrasonically cleaned multiple times with ultrapure water and then anhydrous ethanol to remove any residual chemicals in the pores. After drying, the self-supporting (TaNbHfZrTi)IrO2 catalyst was obtained.

[0059] Figure 4 This is an SEM image of the (TaNbHfZrTi)IrO2 catalyst prepared in Example 3. The results show that the BCC structure on the surface is corroded to form a dendritic structure, and the branches are dotted with Ir-rich nanoparticles with a particle size of 300-500 nm. This indicates that the BCC phase was successfully partially corroded by chemical dealloying, increasing the specific surface area of the active elements.

[0060] (Example 4)

[0061] The (TaNbHfZrTi) prepared in Example 2 99The (IrRu)1 high-entropy alloy precursor was annealed at 1200°C for 4 hours. The annealed high-entropy alloy precursor was then chemically dealloyed in a 0.5M HF solution at room temperature for 12 hours. The precursor was then ultrasonically cleaned multiple times with ultrapure water and then anhydrous ethanol to remove residual chemicals in the pores. After drying, the self-supporting (TaNbHfZrTi) (IrO2RuO2) catalyst was obtained.

[0062] Figure 5 This is an SEM image of the (TaNbHfZrTi) (IrO2RuO2) catalyst prepared in Example 4. The results show that the BCC structure on the surface is partially corroded to form a dendritic structure, and the branches are dotted with Ir- and Ru-rich nanoparticles with a particle size of 100-300 nm. This indicates that the BCC phase was successfully partially corroded by chemical dealloying, increasing the specific surface area of the active elements.

[0063] (Test Example 1)

[0064] The (TaNbHfZrTi) prepared in Example 1 95 A three-electrode system consisting of an Ir5 high-entropy alloy precursor and the (TaNbHfZrTi)IrO2 catalyst prepared in Example 3 was used as the working electrode, a platinum wire electrode as the auxiliary electrode, and an Ag / AgCl standard electrode as the reference electrode. Linear voltammetry was performed in a 0.5 M H2SO4 solution at a scan rate of 50 mV / s.

[0065] Figure 6 (TaNbHfZrTi) prepared in Example 1 95 The linear sweep voltammetry curves of the Ir5 high entropy alloy precursor and the (TaNbHfZrTi)IrO2 catalyst prepared in Example 3 in 0.5 M H2SO4 electrolyte were compared. The results show that the (TaNbHfZrTi)IrO2 catalyst obtained after selective dealloying has a high electrochemical performance of 10 mA cm -2 The overpotential required at the catalytic current density is only 196 mV, while (TaNbHfZrTi) 95 The overpotential required for the Ir5 high entropy alloy precursor to reach the same current density is 587mV, and the overpotential of (TaNbHfZrTi) IrO2 is much lower than that of (TaNbHfZrTi) 95 Ir5 high entropy alloy precursor, indicating that it has excellent acidic oxygen evolution catalytic activity.

[0066] Figure 7 (TaNbHfZrTi) prepared in Example 1 95Comparison of the Tafel slopes of the Ir5 high entropy alloy precursor and the (TaNbHfZrTi) IrO2 catalyst prepared in Example 3 in 0.5 M H2SO4 electrolyte. The results show that the Tafel slope of the (TaNbHfZrTi) IrO2 catalyst is only 27.01 mV / dec, while the (TaNbHfZrTi) 95 The Tafel slope of the Ir5 high entropy alloy precursor is 425.04 mV / dec, indicating that the (TaNbHfZrTi)IrO2 catalyst exhibits higher catalytic activity and faster electrocatalytic kinetic response.

[0067] (Test Example 2)

[0068] The (TaNbHfZrTi)IrO2 catalyst prepared in Example 3 was used as the working electrode, the platinum wire electrode was used as the auxiliary electrode, and the Ag / AgCl standard electrode was used as the reference electrode to form a three-electrode system. A constant current test was performed in a 0.5 M H2SO4 solution with a current density of 1 A cm -2 .

[0069] Figure 8 The (TaNbHfZrTi) IrO2 catalyst prepared in Example 3 was tested at a current density of 1 A cm -2 The voltage-time curve under the conditions is given by Figure 8 It can be seen that the catalyst can be used in 0.5M H2SO4 solution at 1A cm -2 The stable operation time exceeded 100 hours under the current density condition of 10 ...

[0070] In summary, the present invention successfully constructs a self-supporting, dendritic, porous framework composed of nanoscale IrO2 / IrO2RuO2 mixed oxide particles by organically combining a high-entropy alloy body-centered cubic (BCC) substrate with trace amounts of precious metal active components, coupled with precise physical metallurgical smelting, suction casting, annealing homogenization, and chemical dealloying processes. This structure ensures the continuity of the conductive network and the mechanical stability of the framework, while significantly enhancing the specific surface area of the precious metal active sites and the electron / proton transport efficiency. Electrochemical testing demonstrates that the prepared catalyst exhibits low overpotential, low Tafel slope, and extremely long stable operating life in acidic OER, demonstrating its promising application in proton exchange membrane electrolyzers and other high-intensity oxygen evolution applications. This method offers advantages such as process controllability, cost controllability (low precious metal usage), and ease of scale-up, providing a practical new approach for the development of efficient and durable acidic OER catalysts.

[0071] The remaining examples can be implemented similarly to the above examples, with the difference being that the nominal composition of the ingredients is varied to obtain different microstructures. The dealloying parameters are then adjusted to obtain catalysts combining noble metals with refractory multi-principal elements. These prepared materials all have self-supporting structures and exhibit excellent acidic OER performance.

[0072] Other embodiments of the present invention will readily occur to those skilled in the art after considering the specification and practicing what is disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as illustrative only, and the present invention is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof.

Claims

1. A high entropy alloy catalyst, characterized in that The catalyst is composed of a high entropy alloy consisting of a refractory metal component A and a noble metal active component B; The composition expression of the high entropy alloy is A x B y , wherein A is composed of multiple elements selected from Ta, Nb, Hf, Zr, Ti, W, and Mo, B is at least one element selected from Ir, Os, and Ru, and x and y are atomic percentages of the elements, satisfying 95≤x≤99, 1≤y≤5, and x+y=100.

2. The catalyst according to claim 1, characterized in that A is composed of Ta, Nb, Hf, Zr and Ti, B is Ir, and the composition expression of the high entropy alloy is (TaNbHfZrTi) x Ir y .

3. The catalyst according to claim 1, characterized in that A is composed of Ta, Nb, Hf, Zr and Ti, B is composed of Ir and Ru, and the composition expression of the high entropy alloy is (TaNbHfZrTi) x (IrRu) y .

4. The catalyst according to claim 1, 2 or 3, characterized in that The high entropy alloy has a BCC structure, which is mainly composed of the refractory metal component A, wherein the noble metal active component B is dispersed in the BCC structure.

5. The catalyst according to claim 3, characterized in that The high-entropy alloy forms a dendritic support structure of the refractory metal component A under dealloying selective corrosion conditions, thereby increasing the specific surface area of the precious metal active component B while serving as a substrate for the precious metal active component B; and the precious metal active component B is oxidized during the dealloying process to form spherical particles of IrO2 and RuO2 with a particle size of 100~300nm dispersed on the support structure.

6. A method for preparing a high entropy alloy catalyst, characterized in that: The following steps are involved: (a) Ingredients: The raw materials of the high entropy alloy are respectively placed in ultrapure water and anhydrous alcohol and ultrasonically cleaned multiple times. After drying, the raw materials are accurately weighed according to the composition of the high entropy alloy to prepare the raw materials. The composition expression of the high entropy alloy is A x B y , wherein A is composed of multiple elements selected from Ta, Nb, Hf, Zr, Ti, W, and Mo, B is at least one element selected from Ir, Os, and Ru, and x and y are atomic percentages of the elements, satisfying 95≤x≤99, 1≤y≤5, and x+y=100; (b) Melting and Vacuum Casting: Melting the raw materials obtained in step (a) in a non-consumable vacuum arc furnace to obtain a molten alloy with uniform composition; pouring the molten alloy into a water-cooled copper mold using a vacuum casting process to cool and solidify it to form a high-entropy alloy precursor in the form of a rod or plate; (c) Annealing: Annealing the precursor obtained in step (b) to achieve tissue homogenization; (d) Dealloying: The precursor obtained in step (c) is placed in an acidic solution for dealloying to obtain a self-supporting catalyst.

7. The preparation method according to claim 6, characterized in that In step (b), the smelting current is ≥250 A and the smelting temperature is ≥3000°C.

8. The preparation method according to claim 6, characterized in that In step (c), the annealing temperature is 1000-1500°C, and the holding time is 3-5 hours.

9. The preparation method according to claim 6, characterized in that In step (d), the acidic solution is 0.5 M HF, and the dealloying time is 0 to 5 days.

10. The catalyst obtained according to the preparation method according to any one of claims 6 to 9. Use of the catalyst according to claim 10 in acidic OER.

Images