Water electrolysis device, catalyst and preparation method and application of catalyst

Abstract

The invention relates to the technical field of catalysts, in particular to a water electrolysis device, a catalyst and application thereof. The membrane electrode comprises an ion exchange membrane and a catalyst layer arranged on the ion exchange membrane, the catalyst layer comprises a catalyst, the catalyst comprises a matrix and a first coating layer arranged on the surface of the matrix, and the matrix comprises an inner core and a second coating layer arranged on the surface of the inner core; the first coating layer comprises at least one of a metal atom, a metal simple substance, a metal oxide and a metal alloy, and metal elements in the metal atom, the metal simple substance, the metal oxide and the metal alloy comprise a first precious metal element and / or a first transition metal element; the inner core comprises an alloy, the alloy at least comprises an element M and an element N, the element M comprises a second precious metal element or a non-precious metal element, the element N comprises a rare earth metal element or a second transition metal element, and the first precious metal element is different from the second precious metal element; the second cladding layer includes an M metal. The catalyst provided by the invention has good stability and catalytic activity.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and in particular to a water electrolysis device, a catalyst, its preparation method, and its application. Background Technology

[0002] A catalyst is a substance that alters the rate of a chemical reaction without changing its own mass or chemical properties before and after the reaction. Solid catalysts are widely used in various heterogeneous catalytic reactions. They consist of a support and an active component. The support in a solid catalyst plays a role in supporting, dispersing, and diluting the active component, thereby improving the catalyst's strength.

[0003] In chemical reactions, the stability of a catalyst can affect its catalytic performance. Summary of the Invention

[0004] The main objective of this invention is to provide a water electrolysis device that improves the stability of the catalyst, thereby increasing the service life of the water electrolysis device.

[0005] To achieve the above objectives, the present invention proposes a water electrolysis device, comprising a membrane electrode, wherein the membrane electrode comprises an ion exchange membrane and a catalyst layer disposed on the ion exchange membrane, the catalyst comprises a substrate and a first coating layer disposed on the surface of the substrate, and the substrate comprises a core and a second coating layer disposed on the surface of the core;

[0006] The first coating layer includes at least one of metal atoms, elemental metals, metal oxides, and metal alloys, wherein the metal elements in the metal atoms, elemental metals, metal oxides, and metal alloys include a first noble metal element and / or a first transition metal element;

[0007] The core includes an alloy, which includes at least an element M and an element N. The element M includes a second noble metal element or a non-noble metal element, and the element N includes a rare earth metal element or a second transition metal element. The first noble metal element is different from the second noble metal element.

[0008] The second coating layer comprises M metal.

[0009] The first coating layer is a catalytically active material located on the surface of the substrate, which helps to fully expose the active sites and improve their utilization. The substrate includes a core and a second coating layer located on the surface of the core. The first coating layer is located on the surface of the second coating layer. There is an interaction between the metal of the first coating layer and the metal of the second coating layer, which improves the stability of the first coating layer on the second coating layer. By coating the core with the first and second coating layers, the risk of core detachment can be effectively reduced, the stability of the core can be enhanced, and thus the stability of the catalyst can be improved. Furthermore, the second coating layer is conductive, which enhances the conduction of electrons in the first coating layer during the catalytic reaction and improves the catalytic performance. The catalyst of this application has good stability and catalytic activity. The enhanced stability can increase the operating time of the water electrolysis device, thereby increasing the service life of the water electrolysis device throughout its entire life cycle.

[0010] Optionally, at least one of the following conditions must be met:

[0011] Condition A: The first noble metal element includes at least one of Ir, Ru, Rh, and Pd;

[0012] Condition B: The first transition metal element includes at least one of Fe, Co, Ni, Mn, W, V, Mo, and Cr;

[0013] Condition C: The second noble metal element includes at least one of Pt, Pd, Ru, and Au;

[0014] Condition D: The non-precious metal element includes at least one of Mg, Fe, Co, Ni and Ca;

[0015] Condition E: The rare earth metal element includes at least one of La, Ce, Pr, Sm, Gd, Tb, Dy, Y, and Tm;

[0016] Condition F: The second transition metal element includes at least one of Ti, Nb, W, Ta, and Zr;

[0017] Condition G: The specific surface area of ​​the catalyst is in the range of 500 m². 2 / g to 600m 2 / g;

[0018] Condition H: The volume average particle size of the catalyst is 5 nm to 10 nm;

[0019] Condition I: The volume average particle size of the core is 5 nm to 10 nm;

[0020] Condition J: The thickness of the second coating layer ranges from 1 nm to 1.5 nm;

[0021] Condition K: The second coating layer comprises 3 to 5 layers of M metal atoms;

[0022] Condition L: The second coating layer completely covers the surface of the core;

[0023] Condition M: The thickness of the first coating layer ranges from 1.5 nm to 3 nm;

[0024] Condition N: The molar ratio of element M to element N is 1:1 to 1:3;

[0025] Condition O: The catalyst is located in the pores of the carbon material and / or on the surface of the carbon material;

[0026] Condition P: The kernel has a porous structure;

[0027] Condition Q: The shape of the kernel includes a spherical shape;

[0028] Condition R: The ion exchange membrane includes anion exchange membrane or cation exchange membrane.

[0029] In this application, the first noble metal element includes at least one of Ir, Ru, Rh, and Pd. For example, in one embodiment, the catalyst includes a substrate and a first coating layer disposed on the surface of the substrate. The first coating layer is Ir metal. Because the catalytic reaction is an interfacial reaction, the substrate surface is coated with an Ir layer. The catalytic sites for the oxygen evolution reaction are mainly located on the outer Ir layer. The substrate mainly serves to load Ir, reducing its usage, and to provide a second coating layer as a conductive functional layer to enhance conductivity. It can also be understood that the first coating layer can be grown in situ on the substrate. Its location on the substrate surface fully exposes the active sites, increasing the utilization rate of the active sites, reducing the amount of noble metal Ir used, and exhibiting a stronger interaction with the substrate, resulting in excellent stability. This reduces the catalyst cost while ensuring that the catalytic performance meets application requirements.

[0030] In this application, the first transition metal element includes at least one of Fe, Co, Ni, Mn, W, V, Mo, and Cr.

[0031] For example, in one embodiment, during alkaline water electrolysis, the first coating layer on the substrate surface includes an FeNi alloy, which catalyzes the oxygen evolution reaction.

[0032] In this application, the second noble metal element includes at least one of Pt, Pd, Ru, and Au. For example, in one embodiment, the core includes an alloy that includes at least M and N elements, and the second cladding layer includes an M metal, where the M element includes Pt. The Pt layer can form a conductive network with good conductivity, enhancing the conductivity of the core. In addition, the formation of the Pt layer can also effectively prevent further detachment of the internal alloy, enhancing the stability of the core.

[0033] In this application, the non-precious metal element includes at least one of Mg, Fe, Co, Ni and Ca.

[0034] In this application, the rare earth metal elements include at least one of La, Ce, Pr, Sm, Gd, Tb, Dy, Y, and Tm.

[0035] For example, in one embodiment, the core comprises an alloy that includes at least M and N elements, and the second cladding layer comprises an M metal that includes Pd and the N element includes La. The core is a PdLa alloy, which has stronger stability compared to other transition metal alloys.

[0036] In this application, the second transition metal element includes at least one of Ti, Nb, W, Ta, and Zr.

[0037] For example, in one embodiment, the core comprises an alloy, which includes at least M and N elements, where M includes Pt and N includes Ti or Nb. The core is a PtTi alloy or a PtNb alloy, which exhibits excellent stability under the high oxidation potential conditions of the acidic catalytic oxygen evolution reaction.

[0038] In this application, the specific surface area of ​​the catalyst is in the range of 500 m². 2 / g to 600m 2 / g. It is understandable that a large specific surface area of ​​the catalyst is beneficial for providing abundant active sites, allowing the active sites to be fully utilized. In particular, when the first coating layer includes Ir, setting the first coating layer on the substrate surface reduces the Ir loading while ensuring high activity of the oxygen evolution reaction.

[0039] In this application, the volume average particle size of the catalyst is 5 nm to 10 nm.

[0040] In this application, the volume-average particle size of the core is 5 nm to 10 nm. It is understood that a small core size can provide a large specific surface area.

[0041] In this application, the thickness of the second coating layer ranges from 1 nm to 1.5 nm. It is understood that the second coating layer is located on the surface of the core and plays a role in good conductivity. If the second coating layer is too thin, it may be discontinuous, leading to poor conductivity. The thickness and uniformity of the second coating layer affect the formation of its conductive network in the catalyst, thereby affecting the catalytic activity and stability.

[0042] In this application, the second coating layer includes 3 to 5 layers of M metal atoms. The second coating layer can form a conductive network with good conductivity, which enhances the conductivity of the core. In addition, the formation of the second coating layer can also effectively prevent further shedding of the core and enhance the stability of the core.

[0043] Understandably, double spherical aberration transmission electron microscopy can be used to characterize the M metal atomic layer of the second cladding layer. Specifically, double spherical aberration transmission electron microscopy uses an electron beam to pass through the sample, and diffraction is generated through the interaction between electrons and sample atoms. The image is then formed by the imaging system. Double spherical aberration correction technology can significantly improve the imaging resolution to the atomic level, allowing observation of the atomic arrangement and crystal structure of the material.

[0044] In this application, the second coating layer completely covers the surface of the core. It can be understood that the core surface is provided with a uniform and continuous second coating layer, which forms a conductive network with good conductivity and enhances the conductivity of the core.

[0045] In this application, the thickness of the first coating layer ranges from 1.5 nm to 3 nm. It is understood that the thickness of the first coating layer affects catalyst performance; if it is too thin, it may affect catalytic stability; if it is too thick, the amount of metal used in the first coating layer cannot be effectively reduced, and the mass-charge transport resistance during the catalytic process will increase. Therefore, the thickness of the first coating layer during preparation is approximately 2 nm to 3 nm. It is also understood that when the catalyst is applied in a water electrolysis device, the catalyst may detach as the catalytic reaction proceeds, resulting in a thinning of the first coating layer. After catalyst use, the thickness of the first coating layer may decrease by 2 to 5 atomic layers, approximately 0.3 nm to 1 nm, and the thickness of the first coating layer after use may be 1.5 nm to 2 nm.

[0046] In this application, the molar ratio of element M to element N is from 1:1 to 1:3. For example, in one embodiment, element M includes Pt, and element N includes rare earth metals. The molar ratio of element M to element N ranges from 1:1 to 1:3. Different ratios may result in different alloy stability and catalytic performance. The atomic ratio of different metals in the core will affect the different alloy structures formed, thereby affecting the conductivity of the second coating layer.

[0047] In this application, the catalyst is located in the pores and / or surface of the carbon material. It is understood that having the catalyst located in the pores and / or surface of the carbon material helps to disperse and stabilize the catalyst, exposes the active sites of the catalyst within the catalyst layer, and provides channels for the feedstock and products during the catalytic process. During the catalytic generation of oxygen, oxygen can escape from the pores, releasing the active sites and improving catalytic efficiency.

[0048] In this application, the core has a porous structure. It is understood that a porous core can increase the specific surface area of ​​the core. The size of the core and the internal pore structure affect the overall specific surface area of ​​the catalyst, which in turn affects the distribution and loading of the first coating layer on the substrate surface and the exposure degree of active sites in the first coating layer, thereby affecting the catalytic activity.

[0049] In this application, the shape of the core includes spherical. It is understood that the core structure includes spherical particles. Compared with the rod-shaped structure, the spherical structure is smaller in size and has a larger specific surface area, which is more conducive to the loading of the first coating layer and the exposure of active sites. This reduces the loading of the first coating layer while improving the utilization rate of active sites and improving catalytic performance.

[0050] In this application, the ion exchange membrane includes anion exchange membrane or cation exchange membrane. For example, when the first coating layer includes Ir, the ion exchange membrane can be a cation exchange membrane, and when the first coating layer includes FeNi, the ion exchange membrane can be anion exchange membrane.

[0051] Optionally, this application also provides a catalyst, including a matrix and a first coating layer disposed on the surface of the matrix, wherein the matrix includes a core and a second coating layer disposed on the surface of the core;

[0052] The first coating layer includes at least one of metal atoms, elemental metals, metal oxides, and metal alloys, wherein the metal elements in the metal atoms, elemental metals, metal oxides, and metal alloys include a first noble metal element and / or a first transition metal element;

[0053] The core includes an alloy, which includes at least an element M and an element N. The element M includes a second noble metal element or a non-noble metal element, and the element N includes a rare earth metal element or a second transition metal element. The first noble metal element is different from the second noble metal element.

[0054] The second coating layer comprises M metal.

[0055] Optionally, at least one of the following conditions must be met:

[0056] Condition A: The first noble metal element includes at least one of Ir, Ru, Rh, and Pd;

[0057] Condition B: The first transition metal element includes at least one of Fe, Co, Ni, Mn, W, V, Mo, and Cr;

[0058] Condition C: The second noble metal element includes at least one of Pt, Pd, Ru, and Au;

[0059] Condition D: The non-precious metal element includes at least one of Mg, Fe, Co, Ni and Ca;

[0060] Condition E: The rare earth metal element includes at least one of La, Ce, Pr, Sm, Gd, Tb, Dy, Y, and Tm;

[0061] Condition F: The second transition metal element includes at least one of Ti, Nb, W, Ta, and Zr;

[0062] Condition G: The specific surface area of ​​the catalyst is in the range of 500 m². 2 / g to 600m 2 / g;

[0063] Condition H: The volume average particle size of the catalyst is 5 nm to 10 nm;

[0064] Condition I: The volume average particle size of the core is 5 nm to 10 nm;

[0065] Condition J: The thickness of the second coating layer ranges from 1 nm to 1.5 nm;

[0066] Condition K: The second coating layer comprises 3 to 5 layers of M metal atoms;

[0067] Condition L: The second coating layer completely covers the surface of the core;

[0068] Condition M: The thickness of the first coating layer ranges from 1.5 nm to 3 nm;

[0069] Condition N: The molar ratio of element M to element N is 1:1 to 1:3;

[0070] Condition O: The catalyst is located in the pores of the carbon material and / or on the surface of the carbon material;

[0071] Condition P: The kernel has a porous structure;

[0072] Condition Q: The shape of the kernel includes a sphere.

[0073] Optionally, this application also provides a method for preparing a catalyst, comprising:

[0074] Prepare the kernel;

[0075] A first coating layer is prepared on the surface of the core to obtain the substrate;

[0076] A first coating layer is prepared on the surface of the substrate to obtain a catalyst;

[0077] The first coating layer includes at least one of metal atoms, elemental metals, metal oxides, and metal alloys, wherein the metal elements in the metal atoms, elemental metals, metal oxides, and metal alloys include a first noble metal element and / or a first transition metal element;

[0078] The core includes an alloy, which includes at least an element M and an element N. The element M includes a second noble metal element or a non-noble metal element, and the element N includes a rare earth metal element or a second transition metal element. The first noble metal element is different from the second noble metal element.

[0079] The second coating layer comprises M metal.

[0080] In the process of preparing the catalyst, the preparation method includes preparing the core, preparing a first coating layer on the surface of the core to obtain the matrix. It is understood that the core can be prepared in a laboratory or purchased. The core comprises an alloy, which includes at least M and N elements. The core can be prepared using existing techniques reported in the literature. The preparation of the first coating layer on the core surface can also be done using existing techniques reported in the literature, for example, using Ar... + Plasma sputtering breaks down the target material into atomic vapor, which forms the first coating layer on the core surface.

[0081] In the process of preparing the first coating layer on the substrate surface to obtain the catalyst, existing technologies reported in the literature can also be used. For example, the first coating layer can be formed on the substrate surface by physical vapor deposition.

[0082] Optionally, at least one of the following conditions must be met:

[0083] Condition A: The kernel preparation step includes:

[0084] The M element source, N element source, and stabilizer are mixed to obtain a mixture;

[0085] The mixture was calcined in a reducing gas atmosphere, and then cooled to obtain a calcined sample.

[0086] The calcined sample was treated in an acidic solution, washed with water, and dried to obtain the core MN alloy;

[0087] Condition B: The step of preparing the first coating layer on the surface of the core to obtain the substrate includes: calcining the core in a reducing gas atmosphere, cooling after calcination, and obtaining a substrate with the first coating layer on the surface of the core, wherein the substrate includes an MN alloy and an M metal disposed on the surface of the MN alloy;

[0088] Condition C: The step of preparing the first coating layer on the surface of the substrate to obtain the catalyst includes:

[0089] The matrix and the first coated precursor are dispersed in a solution and heated by microwave to obtain a catalyst with a first coating layer on the surface of the matrix.

[0090] In the process of preparing the core, the core MN alloy is synthesized by high-temperature pyrolysis in a reducing atmosphere. The alloy is then acid-washed and etched in an acidic medium to remove oxide impurities. At the same time, the N atoms on the alloy surface are etched. At high temperature, the alloy undergoes segregation effect, and the M atoms on the alloy surface are reconstructed to form a second coating layer of M metal. Finally, a substrate with M metal on the surface of the MN alloy is formed.

[0091] In the process of preparing the first coating layer on the substrate surface, the substrate is used as a support, and the first coating layer is grown in situ on the substrate surface.

[0092] Optionally, at least one of the following conditions must be met:

[0093] Condition A: The step of mixing the M element source, N element source, and stabilizer to obtain a mixture includes: mixing the M element source, N element source, stabilizer, and carbon material, and grinding to obtain a mixture;

[0094] Condition B: The step of calcining the mixture in a reducing gas atmosphere and cooling it after calcination to obtain a calcined sample includes: removing oxygen from the reaction vessel containing the mixture, raising the temperature from room temperature to 650°C to 750°C at a rate of 2°C / min to 10°C / min, calcining at a constant temperature for 30 min to 120 min, and cooling to obtain a calcined sample.

[0095] Condition C: In the step of calcining the core in a reducing gas atmosphere and cooling it after calcination to obtain a substrate with a first coating layer on the surface of the core, wherein the substrate includes an MN alloy and an M metal disposed on the surface of the MN alloy, the calcination temperature is 300°C to 400°C and the calcination time is 3h to 5h.

[0096] Condition D: In the step of dispersing the matrix and the first coating precursor in a solution and heating them with microwave to obtain a catalyst with a first coating layer on the surface of the matrix, the power of the microwave heating is 200W to 800W, the temperature of the microwave heating is 140℃ to 180℃, and the time of the microwave heating is 15min to 45min.

[0097] The process of preparing the core also includes using carbon materials as a carrier for dispersing the alloy, reducing the risk of alloy agglomeration, and enabling the first coating layer to grow continuously and uniformly on the alloy surface.

[0098] In the process of preparing the core, oxygen in the reaction vessel is first removed to reduce the occurrence of side reactions. For example, rare earth metals have a strong affinity for oxygen, and rare earth metals synthesized under atmospheric conditions are easily oxidized into rare earth oxides.

[0099] In the core preparation process, the MN alloy core is synthesized by high-temperature pyrolysis in a reducing atmosphere, with calcination conditions meeting the aforementioned range. For example, the temperature is increased from room temperature to 700°C at a rate of 10°C / min, and then calcined at a constant temperature for 30 min to obtain the core. Further, to form a second coating layer on the core surface, the alloy is acid-etched in an acidic medium to remove oxide impurities. Simultaneously, nitrogen atoms on the alloy surface are etched, causing segregation at high temperature. Calcination conditions meeting the aforementioned range are maintained, for example, a calcination temperature of 300°C and a calcination time of 3 h, causing nitrogen (M) atoms to segregate. After cooling to room temperature, M atoms are reconstructed on the alloy surface to form a second coating layer of M metal, ultimately forming a substrate of M metal on the surface of the MN alloy.

[0100] During the in-situ growth of the first coating layer on the substrate surface, microwave heating reaction is used, and the microwave reaction conditions meet the above range. For example, the microwave heating power is 200W, the microwave heating temperature is 140℃, and the microwave heating time is 20min.

[0101] Optionally, at least one of the following conditions must be met:

[0102] Condition A: The source of element M includes at least one of H2PtCl6·6H2O, (NH4)2PtCl6, Pt(NH3)2(NO2)2, and Pt(acac);

[0103] Condition B: The N element source includes at least one of lanthanum chloride hexahydrate, lanthanum nitrate, and lanthanum acetate;

[0104] Condition C: The stabilizer includes at least one of cyanamide, dicyandiamide, and melamine;

[0105] Condition D: The carbon material includes at least one of carbon black, graphene, and Mxene;

[0106] Condition E: The first coated precursor includes IrCl3·H2O, Na2[IrCl6] hydrate, Ir(NO3)3, and Ir4(CO). 12 At least one of them;

[0107] Condition F: The molar ratio of the M element source, the N element source, and the stabilizer is 1:1:20 to 1:3:20;

[0108] Condition G: Every 100 mg of the M element source corresponds to 200 mg to 500 mg of the carbon material;

[0109] Condition H: 0.01 mol to 0.1 mol of the first coating precursor corresponds to every 100 mg of the MN alloy.

[0110] In the preparation of the core, the M element source includes at least one of H₂PtCl₆·6H₂O, (NH₄)₂PtCl₆, Pt(NH₃)₂(NO₂)₂, and Pt(acac). The N element source includes at least one of lanthanum chloride hexahydrate, lanthanum nitrate, and lanthanum acetate. The stabilizer includes at least one of cyanamide, dicyandiamide, and melamine. The carbon material includes at least one of carbon black, graphene, and Mxene. The first coating precursor includes IrCl₃·H₂O, Na₂[IrCl₆] hydrate, Ir(NO₃)₃, and Ir₄(CO). 12 At least one of the following. The molar ratio of M element source, N element source, and stabilizer is 1:1:20 to 1:3:20 to improve the dispersion of M element ions and N element ions, forming a uniform MN alloy. Each 100mg of M element source corresponds to 200mg to 500mg of carbon material, so that the core is uniformly dispersed on the carbon material.

[0111] During the preparation of the first coating layer on the substrate surface, 0.01 mol to 0.1 mol of the first coating precursor corresponds to every 100 mg of MN alloy. It is understandable that the higher the loading ratio of the first coating precursor, the thicker the first coating layer may be, and the performance may be improved. However, at the same time, it will lead to an increase in the loading amount of the first coating layer and an increase in cost.

[0112] Optionally, this application also provides an anode catalyst for water electrolysis, wherein the anode catalyst for water electrolysis comprises the catalyst described above, or the anode catalyst for water electrolysis comprises a catalyst prepared by the method described above.

[0113] Optionally, this application also provides an application of the aforementioned water electrolysis device.

[0114] The catalyst provided in this application includes a matrix and a first coating layer disposed on the surface of the matrix. The matrix includes a core and a second coating layer disposed on the surface of the core. The first coating layer includes at least one of metal atoms, elemental metals, metal oxides, and metal alloys. The metal elements in the metal atoms, elemental metals, metal oxides, and metal alloys include a first noble metal element and / or a first transition metal element. The core includes an alloy, which includes at least an element M and an element N. The element M includes a second noble metal element or a non-noble metal element, and the element N includes a rare earth metal element or a second transition metal element. The first noble metal element and the second noble metal element are different. The second coating layer includes a metal M. The first coating layer is a catalytically active material located on the surface of the substrate, which helps to fully expose the active sites and improve their utilization. The substrate includes a core and a second coating layer located on the surface of the core. The first coating layer is located on the surface of the second coating layer. There is an interaction between the metal of the first coating layer and the metal of the second coating layer, which improves the stability of the first coating layer on the second coating layer. By coating the core with the first and second coating layers, the risk of core detachment can be effectively reduced, the stability of the core can be enhanced, and thus the stability of the catalyst can be improved. Furthermore, the second coating layer is conductive, which enhances the conduction of electrons in the first coating layer during the catalytic reaction and improves the catalytic performance. The catalyst of this application has good stability and catalytic activity, which helps to improve the service life of the water electrolysis device. Attached Figure Description

[0115] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0116] Figure 1 This is a schematic diagram of the structure of the catalyst in Example 1 of this application;

[0117] Figure 2 This is a transmission electron microscope (TEM) image (TED) of the catalyst in Example 1 of this application;

[0118] Figure 3 This is the X-ray diffraction (XRD) pattern of the catalyst in Example 1 of this application;

[0119] Figure 4 This is a high-angle ring dark-field scanning transmission electron microscope (HAADF-STEM) image of the catalyst in Example 1 of this application;

[0120] Figure 5 This is the energy dispersive spectroscopy (EDS) spectrum of Pt element in the catalyst of Example 1 of this application;

[0121] Figure 6 This is the energy dispersive spectroscopy (EDS) spectrum of La in the catalyst of Example 1 of this application;

[0122] Figure 7 This is the energy dispersive spectroscopy (EDS) spectrum of Ir element in the catalyst of Example 1 of this application;

[0123] Figure 8 These are linear voltammetric scan curves of Embodiment 1 and Comparative Example 1 of this application;

[0124] Figure 9 This is a constant potential timing current curve diagram of Embodiment 1 of this application;

[0125] Figure 10 This is a schematic diagram of the process for preparing the catalyst in this application.

[0126] Explanation of icon numbers:

[0127] label name label name 100 catalyst 20 Second coating layer 10 kernel 30 First coating layer

[0128] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0129] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0130] The catalyst, its preparation method, and its application are disclosed in detail below with appropriate reference to the accompanying drawings. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of essentially the same 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 for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0131] 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 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 "ab" 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.

[0132] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0133] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0134] 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 mention that the method may also include step (c) indicates 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.

[0135] Some chemical reactions are subject to harsh conditions, and the stability of catalysts can be affected when subjected to adverse reaction environments, which in turn affects the performance of water electrolysis devices.

[0136] To improve the performance of a water electrolysis device, this application enhances the stability of the catalyst, enabling it to withstand harsh reaction environments and thereby improving the performance of the device. The proposed water electrolysis device includes a membrane electrode, comprising an ion exchange membrane and a catalyst layer disposed on the ion exchange membrane. The catalyst comprises a substrate and a first coating layer disposed on the surface of the substrate. The substrate comprises a core and a second coating layer disposed on the surface of the core. The first coating layer comprises at least one of a metal atom, a metal element, a metal oxide, and a metal alloy. The metal element in the metal atom, metal element, metal oxide, or metal alloy includes a first noble metal element and / or a first transition metal element. The core comprises an alloy, which includes at least an element M and an element N. The element M includes a second noble metal element or a non-noble metal element, and the element N includes a rare earth metal element or a second transition metal element. The first noble metal element and the second noble metal element are different. The second coating layer comprises a metal M.

[0137] The matrix serves a supporting function, such as Figure 1 As shown, a schematic diagram of a catalyst 100 is presented. The matrix includes a core 10 and a second coating layer 20 disposed on the surface of the core 10. The matrix supports a first coating layer 30, meaning the first coating layer 30 is located on the surface of the matrix. The matrix includes a core and a second coating layer disposed on the surface of the core. The core comprises an alloy, which includes at least elements M and N. Element M includes a second noble metal element or a non-noble metal element, and element N includes a rare earth metal element or a second transition metal element. Compared to oxide matrices such as titanium-based and niobium-based matrices, the matrix of this application can enhance the conductivity of the catalyst, thereby enhancing its catalytic activity.

[0138] Second coating layer, such as Figure 1 As shown, the second covering layer 20 is located on the surface of the kernel 10, which can cover the kernel, reduce the risk of the kernel being exposed to the environment, and improve the stability of the kernel.

[0139] First coating layer, such as Figure 1 As shown, the first coating layer 30 is located on the surface of the second coating layer 20, which fully exposes the first coating layer to the environment, increases the area of ​​the first coating layer exposed to the environment, helps to fully expose the active sites, and improves the utilization rate of the active sites.

[0140] It is understood that the core includes an alloy, which includes at least elements M and N. Element M includes a second noble metal element or a non-noble metal element, and element N includes a rare earth metal element or a second transition metal element. For example, in one embodiment, element M is a second noble metal element and element N is a rare earth metal element. The MN alloy thus formed has good stability.

[0141] It is understood that the second coating layer includes M metal, that is, M metal is located on the surface of the alloy, for example, M metal is located on the surface of MN alloy, which helps to form a uniform second coating layer. The second coating layer provides electrical conductivity. M metal being located on the surface of MN alloy makes the whole has good electrical conductivity, which helps to enhance the conduction of electrons in the first coating layer during the catalytic reaction and improve catalytic performance.

[0142] It is understood that the first coating layer includes at least one of metal atoms, elemental metals, metal oxides, and metal alloys. The metal element in the metal atoms, elemental metals, metal oxides, and metal alloys includes a first noble metal element and / or a first transition metal element. The first coating layer is a catalytically active substance. The catalytically active substance can take the form of at least one of metal atoms, elemental metals, metal oxides, and metal alloys. Here, metal atoms refer to single metal atoms that have not formed a metal elemental phase and have not formed metal-metal bonds. Instead, they are stabilized on the matrix through coordination with the matrix. Elemental metals are generally pure substances in which metal atoms form metal-metal bonds and are arranged in a specific packing pattern.

[0143] For example, in one embodiment, the first coating layer includes elemental Ir for catalyzing the oxygen evolution reaction in a proton exchange membrane water electrolysis device; in another embodiment, the first coating layer includes IrO2 or an Ir atomic layer. It is understood that an Ir single-atom coating layer would further reduce the Ir loading and reduce costs.

[0144] The metallic elements in metal atoms, metallic elements, metal oxides, and metal alloys include the first noble metal element and / or the first transition metal element. The metallic elements in metal atoms, metallic elements, metal oxides, and metal alloys can be the first noble metal element, the first transition metal element, or both. For example, a metallic element can be composed of the first noble metal element, the first transition metal element, or two metallic elements, one of which is composed of the first noble metal element and the other of which is composed of the first transition metal element.

[0145] To improve the performance of a water electrolysis device, this application enhances the performance of the device by improving the stability of the catalyst. The water electrolysis device includes a membrane electrode, which comprises an ion exchange membrane and a catalyst layer disposed on the ion exchange membrane. The catalyst layer includes a catalyst. The catalyst provided in this application includes a substrate and a first coating layer disposed on the surface of the substrate. The substrate includes a core and a second coating layer disposed on the surface of the core. The first coating layer includes at least one of metal atoms, elemental metals, metal oxides, and metal alloys. The metal element among the metal atoms, elemental metals, metal oxides, and metal alloys includes a first noble metal element and / or a first transition metal element. The core includes an alloy, which includes at least element M and element N. Element M includes a second noble metal element or a non-noble metal element, and element N includes a rare earth metal element or a second transition metal element. The first noble metal element and the second noble metal element are different. The second coating layer includes metal M. The first coating layer is a catalytically active material located on the surface of the substrate, which helps to fully expose the active sites and improve their utilization rate. The substrate includes a core and a second coating layer located on the surface of the core. The first coating layer is located on the surface of the second coating layer. There is an interaction between the metal of the first coating layer and the metal of the second coating layer, which improves the stability of the first coating layer on the second coating layer. By coating the core with the first and second coating layers, the risk of core detachment can be effectively reduced, the stability of the core can be enhanced, and thus the stability of the catalyst can be improved. Furthermore, the second coating layer is conductive, which enhances the conduction of electrons in the first coating layer during the catalytic reaction and improves the catalytic performance. The catalyst of this application has good stability and catalytic activity. The enhanced stability can increase the operating time of the water electrolysis device, thereby increasing the service life of the water electrolysis device throughout its entire life cycle.

[0146] In one embodiment, at least one of the following conditions is satisfied: Condition A: The first noble metal element includes at least one of Ir, Ru, Rh, and Pd; Condition B: The first transition metal element includes at least one of Fe, Co, Ni, Mn, W, V, Mo, and Cr; Condition C: The second noble metal element includes at least one of Pt, Pd, Ru, and Au; Condition D: The non-noble metal element includes at least one of Mg, Fe, Co, Ni, and Ca; Condition E: The rare earth metal element includes at least one of La, Ce, Pr, Sm, Gd, Tb, Dy, Y, and Tm; Condition F: The second transition metal element includes at least one of Ti, Nb, W, Ta, and Zr; Condition G: The specific surface area of ​​the catalyst is in the range of 500 m². 2 / g to 600m 2 / g; Condition H: The volume average particle size of the catalyst is 5nm to 10nm; Condition I: The volume average particle size of the core is 5nm to 10nm; Condition J: The thickness of the second coating layer is 1nm to 1.5nm; Condition K: The second coating layer consists of 3 to 5 layers of M metal atoms; Condition L: The second coating layer completely covers the surface of the core; Condition M: The thickness of the first coating layer is 1.5nm to 3nm; Condition N: The molar ratio of M to N elements is 1:1 to 1:3; Condition O: The catalyst is located in the pores of the carbon material and / or on the surface of the carbon material; Condition P: The core is a porous structure; Condition Q: The shape of the core includes spherical; Condition R: The ion exchange membrane includes anion exchange membrane or cation exchange membrane.

[0147] In one embodiment, the first noble metal element includes at least one of Ir, Ru, Rh, and Pd.

[0148] For example, in one embodiment, the catalyst includes a matrix and a first coating layer disposed on the surface of the matrix. The first coating layer is Ir metal. It is understood that Ir is a precious metal, and its cost as a catalyst is relatively high. Specifically, facing the global energy crisis and environmental pollution challenges, countries are actively exploring the development and utilization of renewable energy. Among various energy carriers, hydrogen energy has advantages such as high energy density and clean zero emissions. It is the fuel with the highest calorific value besides nuclear energy and is considered one of the important carriers for global energy transition. Hydrogen production through renewable energy water electrolysis is an important method for producing hydrogen. Compared with alkaline water electrolysis (AWE) and anion exchange membrane water electrolysis (AEMWE), proton exchange membrane water electrolysis (PEMWE) has higher current density, faster response time, and greater compatibility with renewable energy, making it an important pathway for hydrogen production through water electrolysis.

[0149] In PEMWE, the anodic oxygen evolution reaction (OER) involves a four-electron-proton coupling transfer process, which is kinetically slow and is the main energy-consuming step in water electrolysis. Therefore, there is an urgent need to find efficient and stable catalysts to lower the energy barrier of the anodic OER reaction and accelerate the reaction process. Currently, the most commonly used commercial catalysts in PEMWE are iridium (Ir)-based catalysts, such as Ir black and IrO2. They exhibit excellent catalytic activity and stability in acidic media, but the limited availability and high cost of Ir are one of the important factors limiting the large-scale application of PEMWE. In this application, the first coating layer is an Ir metal. Because the catalytic reaction is an interfacial reaction, the substrate surface is covered with an Ir layer. The catalytic sites for the oxygen evolution reaction are mainly on the outer Ir layer. The substrate mainly serves to support Ir, reduce its amount, and provide a second coating layer as a conductive functional layer to enhance conductivity. It is also understandable that the first coating layer can grow in situ on the substrate, and its location on the substrate surface fully exposes the active sites, increasing the utilization rate of the active sites, reducing the amount of precious metal Ir, and the interaction between it and the substrate is stronger, with excellent stability, thus reducing the cost of the catalyst while ensuring that the catalytic performance meets the application requirements.

[0150] In one embodiment, the first transition metal element includes at least one selected from Fe, Co, Ni, Mn, W, V, Mo, and Cr.

[0151] The metal elements in the first coating layer include a first noble metal element and / or a first transition metal element. For example, in one embodiment, during alkaline water electrolysis, the first coating layer on the substrate surface includes an FeNi alloy, which has the function of catalyzing the oxygen evolution reaction.

[0152] In one embodiment, the second noble metal element includes at least one of Pt, Pd, Ru, and Au. For example, in one embodiment, the core includes an alloy comprising at least M and N elements, and the second cladding layer includes an M metal, where the M element includes Pt. The Pt metal layer can form a conductive network with good conductivity, enhancing the conductivity of the core. Furthermore, the formation of the Pt metal layer can effectively prevent further detachment of the internal PtN alloy, enhancing the stability of the core.

[0153] In one embodiment, the non-precious metal element includes at least one of Mg, Fe, Co, Ni and Ca.

[0154] For example, the core may include an alloy, which includes at least elements M and N, where element M includes non-precious metal elements. In one embodiment, element M includes Mg and element N includes La. In the acidic water electrolysis process, the core alloy may be MgLa. In another embodiment, in the alkaline water electrolysis process, element M includes Fe and element N includes La. The core alloy may be FeLa.

[0155] In one embodiment, the rare earth metal element includes at least one of La, Ce, Pr, Sm, Gd, Tb, Dy, Y, and Tm.

[0156] For example, in one embodiment, the core comprises an alloy that includes at least M and N elements, and the second cladding layer comprises an M metal that includes Pt and the N element that includes La. The core is a PdLa alloy, which has stronger stability compared to other transition metal alloys.

[0157] In one embodiment, the second transition metal element includes at least one selected from Ti, Nb, W, Ta, and Zr. It is understood that selecting a metal with acid resistance and high potential resistance as the second transition metal element helps improve the stability of the catalyst. For example, in one embodiment, the core comprises an alloy including at least elements M and N, where M includes Pt and N includes Ti or Nb. A PtTi alloy or PtNb alloy as the core exhibits excellent stability under high oxidation potential conditions in acidic catalytic oxygen evolution reactions.

[0158] In one embodiment, the specific surface area of ​​the catalyst is in the range of 500 m². 2 / g to 600m 2 / g. It is understandable that a large specific surface area of ​​the catalyst is beneficial for providing abundant active sites, allowing the active sites to be fully utilized. In particular, when the first coating layer includes Ir, setting the first coating layer on the substrate surface reduces the Ir loading while ensuring high activity of the oxygen evolution reaction.

[0159] The above 500m 2 / g to 600m 2 In / g, the values ​​include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments and 500m. 2 / g、510m 2 / g、520m 2 / g、530m 2 / g、540m 2 / g、550m 2 / g、560m 2 / g、570m 2 / g、580m 2 / g、590m 2 / g、600m 2 / g, etc., and the range of values ​​between any two of the above point values.

[0160] In one embodiment, the volume average particle size of the catalyst is 5 nm to 10 nm.

[0161] In one embodiment, the volume-average particle size of the core is 5 nm to 10 nm. It is understood that a small core size can provide a large specific surface area.

[0162] It is understandable that volume average particle size is the particle size corresponding to a cumulative particle size distribution percentage of 50% in a sample. Physically, it means that 50% of the particles are larger than it, and 50% are smaller. It can be characterized and tested using a Malvern laser particle size analyzer, such as the Malvern Mastersizer-3000, in accordance with GB / T 19077-2016.

[0163] The values ​​in the range of 5nm to 10nm include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments, as well as 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, etc., and the range values ​​between any two of the above point values.

[0164] In one embodiment, the thickness of the second coating layer ranges from 1 nm to 1.5 nm. It is understood that the second coating layer, located on the surface of the core, serves to ensure good conductivity. If the second coating layer is too thin, it may be discontinuous, leading to poor conductivity. The thickness and uniformity of the second coating layer affect the formation of its conductive network within the catalyst, thereby influencing catalytic activity and stability.

[0165] The values ​​in the range of 1nm to 1.5nm include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments, as well as 1nm, 1.1nm, 1.2nm, 1.3nm, 1.4nm, 1.5nm, etc., and the range values ​​between any two of the above point values.

[0166] In one embodiment, the second coating layer comprises 3 to 5 layers of M metal atoms. The second coating layer can form a conductive network with good conductivity, enhancing the conductivity of the core. Furthermore, the formation of the second coating layer can effectively prevent further shedding of the core, enhancing the stability of the core. The second coating layer can be 3, 4, or 5 layers of M metal atoms.

[0167] Understandably, double spherical aberration transmission electron microscopy can be used to characterize the M metal atomic layer of the second cladding layer. Specifically, double spherical aberration transmission electron microscopy uses an electron beam to pass through the sample, and diffraction is generated through the interaction between electrons and sample atoms. The image is then formed by the imaging system. Double spherical aberration correction technology can significantly improve the imaging resolution to the atomic level, allowing observation of the atomic arrangement and crystal structure of the material.

[0168] In one embodiment, the second coating layer completely covers the surface of the core. It is understood that the core surface is provided with a uniform and continuous second coating layer, which forms a conductive network with good conductivity and enhances the conductivity of the core.

[0169] In one embodiment, the thickness of the first coating layer ranges from 1.5 nm to 3 nm. It is understood that the thickness of the first coating layer affects catalyst performance; if it is too thin, it may affect catalytic stability; if it is too thick, it cannot effectively reduce the amount of metal used in the first coating layer and will increase the mass-charge transport resistance during the catalytic process. Therefore, the thickness of the first coating layer during preparation is approximately 2 nm to 3 nm. It is also understood that when the catalyst is applied in a water electrolysis device, the catalyst may detach as the catalytic reaction proceeds, resulting in a thinning of the first coating layer. After catalyst use, the thickness of the first coating layer may decrease by 2 to 5 atomic layers, approximately 0.3 nm to 1 nm, and the thickness of the first coating layer after use may be 1.5 nm to 2 nm.

[0170] The values ​​in the range of 1.5nm to 3nm include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments, as well as 1.5nm, 2nm, 2.5nm, 3nm, etc., and the range values ​​between any two of the above point values.

[0171] In this application, the molar ratio of element M to element N is from 1:1 to 1:3. For example, in one embodiment, element M includes Pt, and element N includes rare earth metals. The molar ratio of element M to element N ranges from 1:1 to 1:3. Different ratios may result in different alloy stability and catalytic performance. The atomic ratio of different metals in the core will affect the different alloy structures formed, thereby affecting the conductivity of the second coating layer.

[0172] The values ​​in the range of 1:1 to 1:3 include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments, as well as 1:1, 1:2, 1:3, etc., and the range values ​​between any two point values ​​mentioned above.

[0173] In one embodiment, the catalyst is located in the pores and / or on the surface of the carbon material. It is understood that having the catalyst located in the pores and / or on the surface of the carbon material facilitates uniform dispersion of the catalyst, helps expose the active sites of the catalyst within the catalyst layer, improves site utilization and catalytic activity, and provides channels for the feedstock and products in the catalytic process. During the catalytic generation of oxygen, oxygen can escape from the channels, releasing the active sites and improving catalytic efficiency.

[0174] In one embodiment, the core has a porous structure. It is understood that a porous core can increase the specific surface area of ​​the core. The size of the core and the internal pore structure affect the overall specific surface area of ​​the catalyst, which in turn affects the distribution and loading of the first coating layer on the substrate surface and the degree of exposure of active sites in the first coating layer, thereby affecting the catalytic activity.

[0175] In one embodiment, the core shape includes a spherical shape. It is understood that the core structure includes spherical particles. Compared with a rod-shaped structure, the spherical structure is smaller in size and has a larger specific surface area, which is more conducive to the loading of the first coating layer and the exposure of active sites. This reduces the loading of the first coating layer while improving the utilization rate of active sites and improving catalytic performance.

[0176] In one embodiment, the ion exchange membrane includes anion exchange membrane or cation exchange membrane. For example, when the first coating layer includes Ir, the ion exchange membrane can be a cation exchange membrane, and when the first coating layer includes FeNi, the ion exchange membrane can be an anion exchange membrane.

[0177] In one embodiment, this application also provides a catalyst, including a matrix and a first coating layer disposed on the surface of the matrix. The matrix includes a core and a second coating layer disposed on the surface of the core. The first coating layer includes at least one of metal atoms, elemental metals, metal oxides, and metal alloys. The metal elements in the metal atoms, elemental metals, metal oxides, and metal alloys include a first noble metal element and / or a first transition metal element. The core includes an alloy, which includes at least an element M and an element N. The element M includes a second noble metal element or a non-noble metal element, and the element N includes a rare earth metal element or a second transition metal element. The first noble metal element and the second noble metal element are different. The second coating layer includes a metal M.

[0178] In one embodiment, at least one of the following conditions is satisfied: Condition A: The first noble metal element includes at least one of Ir, Ru, Rh, and Pd; Condition B: The first transition metal element includes at least one of Fe, Co, Ni, Mn, W, V, Mo, and Cr; Condition C: The second noble metal element includes at least one of Pt, Pd, Ru, and Au; Condition D: The non-noble metal element includes at least one of Mg, Fe, Co, Ni, and Ca; Condition E: The rare earth metal element includes at least one of La, Ce, Pr, Sm, Gd, Tb, Dy, Y, and Tm; Condition F: The second transition metal element includes at least one of Ti, Nb, W, Ta, and Zr; Condition G: The specific surface area of ​​the catalyst is in the range of 500 m². 2 / g to 600m 2 / g; Condition H: The volume average particle size of the catalyst is 5nm to 10nm; Condition I: The volume average particle size of the core is 5nm to 10nm; Condition J: The thickness of the second coating layer is 1nm to 1.5nm; Condition K: The second coating layer consists of 3 to 5 layers of M metal atoms; Condition L: The second coating layer completely covers the surface of the core; Condition M: The thickness of the first coating layer is 1.5nm to 3nm; Condition N: The molar ratio of M to N elements is 1:1 to 1:3; Condition O: The catalyst is located in the pores of the carbon material and / or on the surface of the carbon material; Condition P: The core is a porous structure; Condition Q: The shape of the core includes spherical.

[0179] In one embodiment, such as Figure 10 As shown, this application also provides a method for preparing a catalyst, comprising: preparing a core; preparing a first coating layer on the surface of the core to obtain a matrix; preparing the first coating layer on the surface of the matrix to obtain a catalyst; the first coating layer comprises at least one of metal atoms, elemental metals, metal oxides, and metal alloys, wherein the metal element in the metal atoms, elemental metals, metal oxides, and metal alloys comprises a first noble metal element and / or a first transition metal element; the core comprises an alloy, the alloy comprising at least an element M and an element N, wherein the element M comprises a second noble metal element or a non-noble metal element, and the element N comprises a rare earth metal element or a second transition metal element, wherein the first noble metal element and the second noble metal element are different; and the second coating layer comprises a metal M.

[0180] In the process of preparing the catalyst, the preparation method includes preparing the core, preparing a first coating layer on the surface of the core to obtain the matrix. It is understood that the core can be prepared in a laboratory or purchased. The core comprises an alloy, which includes at least M and N elements. The core can be prepared using existing techniques reported in the literature. The preparation of the first coating layer on the core surface can also be done using existing techniques reported in the literature, for example, using Ar... + Plasma sputtering breaks down the target material into atomic vapor, which forms the first coating layer on the core surface.

[0181] In the process of preparing the first coating layer on the substrate surface to obtain the catalyst, existing technologies reported in the literature can also be used. For example, the first coating layer can be formed on the substrate surface by physical vapor deposition.

[0182] In one embodiment, at least one of the following conditions is satisfied: Condition A: The step of preparing the core includes: mixing an M element source, an N element source, and a stabilizer to obtain a mixture; calcining the mixture in a reducing gas atmosphere, and cooling it after calcination to obtain a calcined sample; treating the calcined sample in an acidic solution, washing it with water, and drying it to obtain a core MN alloy; Condition B: The step of preparing a first coating layer on the surface of the core to obtain a substrate includes: calcining the core in a reducing gas atmosphere, and cooling it after calcination to obtain a substrate with a first coating layer on the surface of the core, the substrate including an MN alloy and an M metal disposed on the surface of the MN alloy; Condition C: The step of preparing a first coating layer on the surface of the substrate to obtain a catalyst includes: dispersing the substrate and a first coating precursor in a solution, and heating them with microwaves to obtain a catalyst with a first coating layer on the surface of the substrate.

[0183] The M element source is a compound containing the M element. The M element source is used to prepare the core and introduce the M element into the core structure. For example, if the M element is Pt, the M element source can be H2PtCl6·6H2O.

[0184] The N element source is a compound containing the N element. The N element source is used to prepare the core, and the N element is introduced into the core structure. For example, if the N element is La, the N element source can be lanthanum chloride hexahydrate.

[0185] The first coating precursor is a raw material used to form the coating layer. The raw material forms the coating layer through a reaction. For example, the first coating precursor is IrCl3·H2O, and the first coating layer is Ir metal.

[0186] Understandably, the role of stabilizers is to stabilize and disperse metal ions. For example, strong coordination bonds are formed between metal ions and N sites with lone pairs of electrons in the CN network of the stabilizer. This stabilizing effect is crucial for both M and N element ions. Without this coordination stabilizing effect, MN alloys cannot be formed.

[0187] In the core preparation process, a core MN alloy is synthesized via high-temperature pyrolysis in a reducing atmosphere. The alloy is then acid-etched in an acidic medium to remove oxide impurities. Simultaneously, nitrogen atoms on the alloy surface are etched, and at high temperature, a segregation effect occurs, leading to the reconstruction of nitrogen atoms on the alloy surface to form a second coating layer of nitrogen metal. Ultimately, an MN alloy substrate with nitrogen metal on its surface is formed. For example, in one embodiment, nitrogen is Pt. The second coating layer of Pt metal is formed by acid etching followed by high-temperature segregation. It typically consists of a densely packed atomic lattice, primarily serving a conductive function. Furthermore, this Pt metal is formed in situ on the surface of the core PtN alloy, resulting in a more stable and uniform second coating layer.

[0188] In the process of preparing the first coating layer on the substrate surface, the substrate is used as a support, and the first coating layer is grown in situ on the substrate surface.

[0189] In one embodiment, at least one of the following conditions is satisfied: Condition A: In the step of mixing the M element source, N element source, and stabilizer to obtain a mixture, the method includes: mixing the M element source, N element source, stabilizer, and carbon material, and grinding to obtain a mixture. It is understood that grinding can make the M element source and N element source more uniformly distributed in the stabilizer, which is beneficial to the formation of MN alloy; Condition B: In the step of calcining the mixture in a reducing gas atmosphere and cooling after calcination to obtain a calcined sample, the method includes: removing oxygen from the reaction vessel containing the mixture, raising the temperature from room temperature to 650°C to 750°C at a heating rate of 2°C / min to 10°C / min, and calcining at a constant temperature. 30 min to 120 min, cooling to obtain calcined sample; Condition C: calcining the core in a reducing gas atmosphere, cooling after calcination to obtain a matrix with a first coating layer on the core surface, the matrix including MN alloy and M metal on the surface of MN alloy, the calcination temperature is 300℃ to 400℃, the calcination time is 3h to 5h; Condition D: dispersing the matrix and the first coating precursor in a solution, microwave heating to obtain a catalyst with a first coating layer on the matrix surface, the microwave heating power is 200W to 800W, the microwave heating temperature is 140℃ to 180℃, the microwave heating time is 15 min to 45 min.

[0190] The process of preparing the core also includes using carbon materials as a carrier for dispersing the alloy, reducing the risk of alloy agglomeration, and enabling the first coating layer to grow continuously and uniformly on the alloy surface.

[0191] In the process of preparing the core, oxygen in the reaction vessel is first removed to reduce the occurrence of side reactions. For example, rare earth metals have a strong affinity for oxygen, and rare earth metals synthesized under atmospheric conditions are easily oxidized into rare earth oxides.

[0192] In the core preparation process, the MN alloy core is synthesized by high-temperature pyrolysis in a reducing atmosphere, with calcination conditions meeting the aforementioned range. For example, the temperature is increased from room temperature to 700°C at a rate of 10°C / min, and then calcined at a constant temperature for 30 min to obtain the core. Further, to form a second coating layer on the core surface, the alloy is acid-etched in an acidic medium to remove oxide impurities. Simultaneously, nitrogen atoms on the alloy surface are etched, causing segregation at high temperature. Calcination conditions meeting the aforementioned range are maintained, for example, a calcination temperature of 300°C and a calcination time of 3 h, causing nitrogen (M) atoms to segregate. After cooling to room temperature, M atoms are reconstructed on the alloy surface to form a second coating layer of M metal, ultimately forming a substrate of M metal on the surface of the MN alloy.

[0193] During the in-situ growth of the first coating layer on the substrate surface, microwave heating reaction is used, and the microwave reaction conditions meet the above range. For example, the microwave heating power is 200W, the microwave heating temperature is 140℃, and the microwave heating time is 20min.

[0194] In one embodiment, at least one of the following conditions is satisfied: Condition A: The source of element M includes at least one of H₂PtCl₆·6H₂O, (NH₄)₂PtCl₆, Pt(NH₃)₂(NO₂)₂, and Pt(acac); Condition B: The source of element N includes at least one of lanthanum chloride hexahydrate, lanthanum nitrate, and lanthanum acetate; Condition C: The stabilizer includes at least one of cyanamide, dicyandiamide, and melamine; Condition D: The carbon material includes at least one of carbon black, graphene, and Mxene; Condition E: The first coating precursor includes IrCl₃·H₂O, Na₂[IrCl₆] hydrate, Ir(NO₃)₃, and Ir₄(CO). 12 At least one of the following: Condition F: The molar ratio of M element source, N element source and stabilizer is 1:1:20 to 1:3:20; Condition G: 200 mg to 500 mg of carbon material per 100 mg of M element source; Condition H: 0.01 mol to 0.1 mol of the first coating precursor per 100 mg of MN alloy.

[0195] In the preparation of the core, the M element source includes at least one of H₂PtCl₆·6H₂O, (NH₄)₂PtCl₆, Pt(NH₃)₂(NO₂)₂, and Pt(acac). The N element source includes at least one of lanthanum chloride hexahydrate, lanthanum nitrate, and lanthanum acetate. The stabilizer includes at least one of cyanamide, dicyandiamide, and melamine. The carbon material includes at least one of carbon black, graphene, and Mxene. The first coating precursor includes IrCl₃·H₂O, Na₂[IrCl₆] hydrate, Ir(NO₃)₃, and Ir₄(CO). 12 At least one of the following. The molar ratio of M element source, N element source, and stabilizer is 1:1:20 to 1:3:20 to improve the dispersion of M and N element ions and form a uniform MN alloy. Each 100 mg of M element source corresponds to 200 mg to 500 mg of carbon material, ensuring that the core is uniformly dispersed on the carbon material. It is understood that the atomic ratio of different metals in the core MN alloy will affect the different alloy structures formed by M and N, thereby affecting the precipitation of N metal during acid etching and the formation of the second coating layer of M metal in the subsequent segregation process, thus affecting the conductivity of the second coating layer. The molar ratio of M element source to N element source within the above range can improve the conductivity of the second coating layer.

[0196] During the preparation of the first coating layer on the substrate surface, 0.01 mol to 0.1 mol of the first coating precursor corresponds to every 100 mg of MN alloy. It is understandable that the higher the loading ratio of the first coating precursor, the thicker the first coating layer may be, and the performance may be improved. However, at the same time, it will lead to an increase in the loading amount of the first coating layer and an increase in cost.

[0197] The values ​​in the range 1:1:20 to 1:3:20 include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments, as well as 1:1:20, 1:2:20, 1:3:20, etc., and the range values ​​between any two point values ​​mentioned above.

[0198] The values ​​in the range of 2℃ / min to 10℃ / min include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments, and 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, etc., as well as the range values ​​between any two of the above point values.

[0199] The values ​​in the range of 650℃ to 750℃ include the minimum and maximum values ​​of this range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments, and 650℃, 680℃, 700℃, 720℃, 740℃, 750℃, etc., as well as the range values ​​between any two of the above point values.

[0200] The values ​​in the range of 30 min to 120 min include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments, as well as 30 min, 50 min, 70 min, 90 min, 100 min, 110 min, 120 min, etc., and the range values ​​between any two of the above point values.

[0201] The values ​​in the range 3h to 5h include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments, as well as 3h, 4h, 5h, etc., and the range values ​​between any two of the above point values.

[0202] The values ​​in the range of 200W to 800W include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments, as well as 200W, 300W, 400W, 500W, 600W, 700W, 800W, etc., and the range values ​​between any two of the above point values.

[0203] The values ​​in the range of 140°C to 180°C include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments, and 140°C, 150°C, 160°C, 170°C, 180°C, etc., as well as the range values ​​between any two of the above point values.

[0204] The values ​​within the range of 15 min to 45 min include the minimum and maximum values ​​of that range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments, and 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, etc., as well as the range values ​​between any two of the above point values.

[0205] For example, in one embodiment, the M element source is H₂PtCl₆·6H₂O, the N element source is LaCl₃·6H₂O, the carbon material is Ketjen Black, and the stabilizer is cyanamide. First, a carbon-supported PtLa alloy is synthesized via high-temperature pyrolysis in a reducing atmosphere. Then, the alloy is acid-etched in an acidic medium to remove oxide impurities. Simultaneously, the La metal atoms on the alloy surface are etched. At high temperature, the alloy undergoes segregation, and Pt atoms are reconstructed on the alloy surface to form a Pt layer. This ultimately forms a substrate with a PtLa alloy (core) and a Pt metal layer (second cladding layer) on its surface. Using this substrate as a carrier, Ir metal (first cladding layer) is grown in situ. The PtLa alloy is relatively small, and a uniform and continuous Pt metal layer is formed on its surface through acid etching. This Pt metal layer can form a conductive network with good conductivity. The formation of the Pt metal layer enhances the conductivity of the core and effectively prevents further core detachment, thus improving core stability. Furthermore, the Ir metal coating on the substrate surface fully exposes active sites, increasing their utilization and reducing the amount of noble Ir required. Therefore, the uniform and continuous Pt metal layer ensures a good conductive network layer in the catalyst structure, guaranteeing its conductivity. The formation of the Pt metal layer prevents the core metal from detaching, ensuring excellent substrate stability. The first coating layer, Ir metal, grows in situ on the substrate surface, forming a stable interface with the substrate. Simultaneously, the large specific surface area of ​​the substrate allows for full utilization of active sites, reducing Ir loading while maintaining high activity in the oxygen evolution reaction. These characteristics enable the catalyst to simultaneously achieve low cost, high activity, and high stability.

[0206] In one embodiment, this application also provides an anode catalyst for water electrolysis, which includes the catalyst as described above, or the anode catalyst for water electrolysis includes a catalyst prepared by the method described above.

[0207] In one embodiment, this application also provides an application of the above-described water electrolysis device. It is understood that the water electrolysis device can be coupled with wind and solar renewable energy sources to produce hydrogen through wind and solar power electrolysis. The produced hydrogen can be used as a feedstock for fuel cells in transportation and energy storage, and can also be used as a feedstock in chemical (ammonia synthesis, methanol synthesis, etc.) and refining industries.

[0208] Example

[0209] Example 1

[0210] Catalyst preparation

[0211] Preparation of the core (PtLa alloy)

[0212] (1) Mix 0.112g of M element source H2PtCl6·6H2O (chloroplatinic acid hexahydrate, 0.22 mmol), 0.013g of N element source LaCl3·6H2O (lanthanum chloride hexahydrate, 0.375 mmol), 0.9g of stabilizer CN2H2 (cyanamide, 21.4 mmol), and 0.168g of carbon material Ketjen black, and grind in an agate mortar for about 20 minutes;

[0213] (2) Place the above-ground mixture into a quartz boat, ventilate it in a tube furnace with a 5% hydrogen-argon mixture for 30 minutes to remove oxygen from the tube furnace and the mixture, and then raise the temperature from room temperature to 700°C at a rate of 10°C / min. Maintain the calcination at 700°C for 30 minutes, and then cool it to room temperature.

[0214] (3) The calcined sample was transferred to a 0.5M H2SO4 solution and reacted at 70°C for 1 hour to remove the surface oxides. Then it was washed with water and dried in a vacuum drying oven at 80°C to obtain the core (PtLa alloy).

[0215] Preparation of matrix

[0216] The core (PtLa alloy) prepared above was transferred back into a tube furnace and calcined at 300°C for 3 hours in a mixture of 5% hydrogen and argon to cause Pt atoms to segregate. Then it was cooled to room temperature to form a substrate with a Pt metal layer on the surface of the PtLa alloy.

[0217] Catalyst preparation

[0218] Take 100 mg of the matrix prepared above, 31.6 mg of the first coating precursor IrCl3□H2O, disperse it in 100 mL of a mixed solution of ethylene glycol and water (volume ratio of ethylene glycol to water is 3:7), sonicate for 60 min, then transfer it to a 250 mL quartz reactor, react at 140 °C for 20 min at 200 W in a microwave reactor, then wash the synthesized sample three times with water and ethanol respectively, and dry it in a vacuum drying oven at 60 °C to obtain the catalyst with Ir metal coated on the matrix surface.

[0219] Catalyst performance testing

[0220] Catalyst size: The morphology and size of the catalyst were characterized using transmission electron microscopy (TEM). The accelerating voltage was 100 kV. The morphology is shown in the figure. Figure 4 As shown, the morphology is granular, and the size is as follows. Figure 2 As shown, the volume average particle size is 10 nm.

[0221] Crystal structure of the catalyst: The crystal structure of the catalyst was determined using X-ray powder diffraction (XRD). Cu-Kα was used as the radiation source, the operating voltage was 40 kV, the current was 25 mA, the 2θ scanning range was 5° to 80°, and the scan rate was 5° / min. -1 The measured XRD pattern is as follows Figure 3 As shown, the core alloy structure corresponds to the Pt5La structure, and the standard card is PDF#17-0364. The characteristic main peak of the outer Ir is about 40.8° at 2θ, which may be masked by the characteristic peak of Pt5La at 40°. EDS characterization can show that the Ir element has been successfully introduced.

[0222] Elemental distribution in the catalyst: The elemental distribution in the sample was characterized using energy-dispersive spectroscopy (EDS) at an accelerating voltage of 200 kV. The elemental distribution is shown in the figure. Figures 5 to 7 As shown, the catalyst structure contains three elements: Ir, Pt, and La, indicating the successful introduction of the Ir shell layer.

[0223] Preparation of a three-electrode electrolytic cell

[0224] Catalyst slurry preparation

[0225] 4 mg of the catalyst powder prepared above and 10 μL of Nafion solution (5 wt.%) were ultrasonically dispersed in 400 μL of isopropanol for about 1 hour at a temperature not exceeding 30°C to ensure uniform dispersion of the catalyst slurry for later use.

[0226] Three-electrode device structure

[0227] Working electrode: Glassy carbon electrode (3 mm in diameter). Take 2 μL of the catalyst slurry prepared above and evenly drop it onto the polished and cleaned glassy carbon electrode. Then, drop 1 μL of 0.3% Nafion isopropanol solution onto the working electrode and allow it to dry in air until ready for use. The catalyst loading is approximately 0.28 mg / cm³. 2 ;

[0228] Counter electrode: Pt sheet electrode

[0229] Reference electrode: Saturated calomel electrode

[0230] Electrolyte: 0.1M perchloric acid solution (0.1M HClO4)

[0231] Assembly: Take about 60 mL of electrolyte into a 100 mL five-hole electrolytic cell, and insert the working electrode, counter electrode and reference electrode in sequence for performance testing.

[0232] Performance testing

[0233] Linear Voltammetric Scan (LSV): The activity of the catalyst was evaluated using the linear voltammetric scan (LSV) method. The assembled three-electrode electrolytic cell was connected to an electrochemical workstation. Before testing, O2 was passed through the electrolyte for approximately 30 to 60 minutes to ensure an oxygen-saturated atmosphere. The voltage range was then set to 1.2 V to 1.7 V vs. RHE, with a scan rate of 5 mV / s. The catalyst was compared with the catalyst at a current density of 10 mA / cm². 2 The lower the overpotential, the better the catalytic activity. Figure 8 It can be seen that the catalyst of Example 1 exhibits a lower overpotential compared to the catalyst of Comparative Example 1, indicating that this structure plays an important role in improving catalyst activity.

[0234] Potentiochronoamperometry (CA): The stability of the catalyst was assessed by potentiochronoamperometry, evaluating the change in current density of the catalyst over time at a potential of 1.48 V vs. RHE. Figure 9 It can be seen that after 50 hours of operation, the catalyst of Example 1 still retains 90% of the current density, indicating that the catalyst of this application has good stability.

[0235] Example 2

[0236] Based on Example 1, the volume average particle size of the catalyst was adjusted.

[0237] Example 3

[0238] Based on Example 1, replace La in the kernel with Pr.

[0239] Example 4

[0240] Based on Example 1, replace La in the kernel with Ti.

[0241] Example 5

[0242] Based on Example 1, Pt in the kernel is replaced with Mg, La in the kernel is replaced with Nb, and Ir in the first coating layer is replaced with Fe.

[0243] Example 6

[0244] Based on Example 1, Pt in the kernel is replaced with Pd, La in the kernel is replaced with Ce, and the first overlay element Ir is replaced with Ru.

[0245] Comparative Example 1

[0246] Using the commercial Ir black catalyst as a comparison sample, based on Example 1, the volume average particle size of the commercial Ir black catalyst is 5 nm under the condition that other conditions remain unchanged.

[0247] Comparative Example 2

[0248] Based on Example 1, there is no second covering layer on the core surface.

[0249] Table 1 List of Examples

[0250]

[0251] In the performance list in Table 1, a lower overpotential indicates better catalytic activity, and a higher current density retention rate indicates better catalyst stability. As can be seen from Table 1, Example 1 has a lower overpotential than Comparative Example 1, indicating that Example 1 has better catalytic activity. In addition, under the same first coating layer element, the Example has a higher current density retention rate than the Comparative Example, indicating that the catalyst in the Example has better stability. Improved catalyst stability helps to increase the service life of the water electrolysis device.

[0252] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A water electrolysis device, characterized in that, The device includes a membrane electrode, which includes an ion exchange membrane and a catalyst layer disposed on the ion exchange membrane. The catalyst layer includes a catalyst, which includes a substrate and a first coating layer disposed on the surface of the substrate. The substrate includes a core and a second coating layer disposed on the surface of the core. The first coating layer includes at least one of metal atoms, elemental metals, metal oxides, and metal alloys, wherein the metal elements in the metal atoms, elemental metals, metal oxides, and metal alloys include a first noble metal element and / or a first transition metal element; The core includes an alloy, which includes at least an element M and an element N. The element M includes a second noble metal element or a non-noble metal element, and the element N includes a rare earth metal element or a second transition metal element. The first noble metal element is different from the second noble metal element. The second coating layer comprises M metal.

2. The water electrolysis device as described in claim 1, characterized in that, At least one of the following conditions must be met: Condition A: The first noble metal element includes at least one of Ir, Ru, Rh, and Pd; Condition B: The first transition metal element includes at least one of Fe, Co, Ni, Mn, W, V, Mo, and Cr; Condition C: The second noble metal element includes at least one of Pt, Pd, Ru, and Au; Condition D: The non-precious metal element includes at least one of Mg, Fe, Co, Ni and Ca; Condition E: The rare earth metal element includes at least one of La, Ce, Pr, Sm, Gd, Tb, Dy, Y, and Tm; Condition F: The second transition metal element includes at least one of Ti, Nb, W, Ta, and Zr; Condition G: The specific surface area of ​​the catalyst is in the range of 500 m². 2 / g to 600m 2 / g; Condition H: The volume average particle size of the catalyst is 5 nm to 10 nm; Condition I: The volume average particle size of the core is 5 nm to 10 nm; Condition J: The thickness of the second coating layer ranges from 1 nm to 1.5 nm; Condition K: The second coating layer comprises 3 to 5 layers of M metal atoms; Condition L: The second coating layer completely covers the surface of the core; Condition M: The thickness of the first coating layer ranges from 1.5 nm to 3 nm; Condition N: The molar ratio of element M to element N is 1:1 to 1:3; Condition O: The catalyst is located in the pores of the carbon material and / or on the surface of the carbon material; Condition P: The kernel has a porous structure; Condition Q: The shape of the kernel includes a spherical shape; Condition R: The ion exchange membrane includes anion exchange membrane or cation exchange membrane.

3. A catalyst, characterized in that, It includes a substrate and a first covering layer disposed on the surface of the substrate, wherein the substrate includes a core and a second covering layer disposed on the surface of the core; The first coating layer includes at least one of metal atoms, elemental metals, metal oxides, and metal alloys, wherein the metal elements in the metal atoms, elemental metals, metal oxides, and metal alloys include a first noble metal element and / or a first transition metal element; The core includes an alloy, which includes at least an element M and an element N. The element M includes a second noble metal element or a non-noble metal element, and the element N includes a rare earth metal element or a second transition metal element. The first noble metal element is different from the second noble metal element. The second coating layer comprises M metal.

4. The catalyst according to claim 3, characterized in that, At least one of the following conditions must be met: Condition A: The first noble metal element includes at least one of Ir, Ru, Rh, and Pd; Condition B: The first transition metal element includes at least one of Fe, Co, Ni, Mn, W, V, Mo, and Cr; Condition C: The second noble metal element includes at least one of Pt, Pd, Ru, and Au; Condition D: The non-precious metal element includes at least one of Mg, Fe, Co, Ni and Ca; Condition E: The rare earth metal element includes at least one of La, Ce, Pr, Sm, Gd, Tb, Dy, Y, and Tm; Condition F: The second transition metal element includes at least one of Ti, Nb, W, Ta, and Zr; Condition G: The specific surface area of ​​the catalyst is in the range of 500 m². 2 / g to 600m 2 / g; Condition H: The volume average particle size of the catalyst is 5 nm to 10 nm; Condition I: The volume average particle size of the core is 5 nm to 10 nm; Condition J: The thickness of the second coating layer ranges from 1 nm to 1.5 nm; Condition K: The second coating layer comprises 3 to 5 layers of M metal atoms; Condition L: The second coating layer completely covers the surface of the core; Condition M: The thickness of the first coating layer ranges from 1.5 nm to 3 nm; Condition N: The molar ratio of element M to element N is 1:1 to 1:3; Condition O: The catalyst is located in the pores of the carbon material and / or on the surface of the carbon material; Condition P: The kernel has a porous structure; Condition Q: The shape of the kernel includes a sphere.

5. The method for preparing the catalyst according to any one of claims 1 to 4, characterized in that, include: Prepare the kernel; A first coating layer is prepared on the surface of the core to obtain the substrate; A first coating layer is prepared on the surface of the substrate to obtain a catalyst; The first coating layer includes at least one of metal atoms, elemental metals, metal oxides, and metal alloys, wherein the metal elements in the metal atoms, elemental metals, metal oxides, and metal alloys include a first noble metal element and / or a first transition metal element; The core includes an alloy, which includes at least an element M and an element N. The element M includes a second noble metal element or a non-noble metal element, and the element N includes a rare earth metal element or a second transition metal element. The first noble metal element is different from the second noble metal element. The second coating layer comprises M metal.

6. The method for preparing the catalyst according to claim 5, characterized in that, At least one of the following conditions must be met: Condition A: The kernel preparation step includes: The M element source, N element source, and stabilizer are mixed to obtain a mixture; The mixture was calcined in a reducing gas atmosphere, and then cooled to obtain a calcined sample. The calcined sample was treated in an acidic solution, washed with water, and dried to obtain the core MN alloy; Condition B: The step of preparing the first coating layer on the surface of the core to obtain the substrate includes: calcining the core in a reducing gas atmosphere, cooling after calcination, and obtaining a substrate with the first coating layer on the surface of the core, wherein the substrate includes an MN alloy and an M metal disposed on the surface of the MN alloy; Condition C: The step of preparing the first coating layer on the surface of the substrate to obtain the catalyst includes: The matrix and the first coated precursor are dispersed in a solution and heated by microwave to obtain a catalyst with a first coating layer on the surface of the matrix.

7. The method for preparing the catalyst according to claim 6, characterized in that, At least one of the following conditions must be met: Condition A: The step of mixing the M element source, N element source, and stabilizer to obtain a mixture includes: mixing the M element source, N element source, stabilizer, and carbon material, and grinding to obtain a mixture; Condition B: The step of calcining the mixture in a reducing gas atmosphere and cooling it after calcination to obtain a calcined sample includes: removing oxygen from the reaction vessel containing the mixture, raising the temperature from room temperature to 650°C to 750°C at a rate of 2°C / min to 10°C / min, calcining at a constant temperature for 30 min to 120 min, and cooling to obtain a calcined sample. Condition C: In the step of calcining the core in a reducing gas atmosphere and cooling it after calcination to obtain a substrate with a first coating layer on the surface of the core, wherein the substrate includes an MN alloy and an M metal disposed on the surface of the MN alloy, the calcination temperature is 300°C to 400°C and the calcination time is 3h to 5h. Condition D: In the step of dispersing the matrix and the first coating precursor in a solution and heating them with microwave to obtain a catalyst with a first coating layer on the surface of the matrix, the power of the microwave heating is 200W to 800W, the temperature of the microwave heating is 140℃ to 180℃, and the time of the microwave heating is 15min to 45min.

8. The method for preparing the catalyst according to claim 7, characterized in that, At least one of the following conditions must be met: Condition A: The source of element M includes at least one of H2PtCl6·6H2O, (NH4)2PtCl6, Pt(NH3)2(NO2)2, and Pt(acac); Condition B: The N element source includes at least one of lanthanum chloride hexahydrate, lanthanum nitrate, and lanthanum acetate; Condition C: The stabilizer includes at least one of cyanamide, dicyandiamide, and melamine; Condition D: The carbon material includes at least one of carbon black, graphene, and Mxene; Condition E: The first coated precursor includes IrCl3·H2O, Na2[IrCl6] hydrate, Ir(NO3)3, and Ir4(CO). 12 At least one of them; Condition F: The molar ratio of the M element source, the N element source, and the stabilizer is 1:1:20 to 1:3:20; Condition G: Every 100 mg of the M element source corresponds to 200 mg to 500 mg of the carbon material; Condition H: 0.01 mol to 0.1 mol of the first coating precursor corresponds to every 100 mg of the MN alloy.

9. An anode catalyst for water electrolysis, characterized in that, The anode catalyst for water electrolysis comprises the catalyst as described in claim 3 or 4, or the anode catalyst for water electrolysis comprises a catalyst prepared by the method of preparing the catalyst as described in any one of claims 5 to 8.

10. An application of the water electrolysis apparatus as described in claim 1 or 2.

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