Oxygen evolution reaction catalyst as well as preparation method and application thereof

Abstract

The invention provides an oxygen evolution reaction catalyst and a preparation method and application thereof, and belongs to the technical field of catalysts and the technical field of electrochemistry. The preparation method comprises the following steps: carrying out air calcination on a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate and a carbon-nitrogen material to obtain the oxygen evolution reaction catalyst.

Description

Technical Field

[0001] This disclosure relates to the fields of catalyst technology and electrochemical technology, and in particular to an oxygen evolution reaction catalyst, its preparation method and application. Background Technology

[0002] The oxygen evolution reaction (OER) is one of the important electrochemical reactions in new energy technologies such as water electrolysis for hydrogen production and fuel cells. However, due to its complex multi-electron transfer process, the OER usually exhibits a high reaction overpotential, which becomes a limiting factor for the efficiency of electrochemical devices. Moreover, compared with alkaline conditions, acidic conditions are thermodynamically unfavorable for the electrocatalysis of oxygen evolution on the anode side, which places higher demands on the selection of active materials.

[0003] In related technologies, acidic OER catalysts are mainly derived from iridium, a precious metal with relatively low global reserves. Iridium-based catalysts have become a research focus for acidic OER catalysts due to their excellent electrocatalytic performance and high stability under acidic conditions. However, iridium resources are scarce and expensive. Summary of the Invention

[0004] In view of the above, in order to at least partially solve at least one of the aforementioned technical problems, this disclosure provides an oxygen evolution reaction catalyst, its preparation method, and its application.

[0005] According to one aspect of this disclosure, a method for preparing an oxygen evolution reaction catalyst is provided, comprising: calcining a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate and carbon-nitrogen materials in air to obtain the oxygen evolution reaction catalyst.

[0006] According to embodiments of this disclosure, the mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitridium material is prepared by the following method: heating a dispersion containing iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitridium material until the solvent in the dispersion evaporates, thereby obtaining the mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitridium material.

[0007] According to embodiments of this disclosure, in the mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate and carbonitridium material described above, the molar ratio of iridium salt to ruthenium salt is 1:(0.1~10).

[0008] According to embodiments of this disclosure, in the mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate and carbonitridium material, the molar ratio of the sum of iridium salt and ruthenium salt to tungsten salt is 1:(0.01~0.20).

[0009] According to embodiments of this disclosure, in the mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate and carbonitridium material described above, the molar ratio of the sum of iridium salt, ruthenium salt and tungsten salt to alkali metal nitrate is (1~10):100.

[0010] According to embodiments of this disclosure, in the mixture of the above-mentioned iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate and carbonitridium material, the mass ratio of the carbonitridium material to the alkali metal nitrate is 1:(50~1000).

[0011] According to embodiments of this disclosure, the calcination temperature is 300~700°C.

[0012] According to embodiments of this disclosure, the calcination time is 1 to 6 hours.

[0013] According to embodiments of this disclosure, the heating rate of the calcination is 1~10°C / min.

[0014] According to embodiments of this disclosure, the calcination temperature is 350~400°C.

[0015] According to embodiments of this disclosure, the carbon-nitrogen materials described above are selected from one or more of melamine, urea, and metal-organic framework materials.

[0016] According to embodiments of this disclosure, the alkali metal nitrate is selected from one or more of sodium nitrate, potassium nitrate, and lithium nitrate.

[0017] According to embodiments of this disclosure, the iridium salt is selected from one or more of chloroiridium acid, chloroiridium acid hydrate, and iridium nitrate.

[0018] According to embodiments of this disclosure, the ruthenium salt is selected from one or more of trinitronitrosylruthenium, hydrated ruthenium trichloride, ruthenium trichloride, and ruthenium dichloride.

[0019] According to embodiments of this disclosure, the tungsten salt is selected from one or more of tungsten chloride, oxides, or alkali metal tungsten salts.

[0020] According to embodiments of this disclosure, the dispersion containing iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbon-nitrogen material is prepared by the following method: mixing a solution containing iridium salt and a solution containing ruthenium salt to obtain a first mixture; adding the alkali metal nitrate to the first mixture to obtain a second mixture; and adding a solution containing tungsten salt and the carbon-based material to the second mixture to obtain the dispersion.

[0021] According to embodiments of this disclosure, the concentration of the solution containing iridium salt is 0.01~1.00 mol / L.

[0022] According to embodiments of this disclosure, the concentration of the solution containing ruthenium salt is 0.02~2.00 mol / L.

[0023] According to embodiments of this disclosure, the concentration of the solution containing tungsten salt is 0.001~0.5 mol / L.

[0024] According to an embodiment of another aspect of this disclosure, an oxygen evolution reaction catalyst prepared by the above-described preparation method is provided.

[0025] According to an embodiment of another aspect of this disclosure, the application of the above-described oxygen evolution reaction catalyst in the field of electrochemical oxygen production is provided.

[0026] According to embodiments of this disclosure, a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitriding material is calcined in air. During calcination, the alkali metal nitrate acts as a flux, and the carbonitriding material acts as a regulating material, promoting the formation of an oxygen evolution reaction catalyst with a nanosheet structure. Furthermore, the carbonitriding material can adjust the valence state and stability of the catalyst during sintering, ensuring the presence of certain low-valence metals in the catalyst, which is beneficial to the material's conductivity. The preparation method provided by the embodiments of this disclosure is simplified and conducive to large-scale production and application.

[0027] The oxygen evolution reaction (OER) catalyst provided in this disclosure has a nanosheet structure, which significantly increases the specific surface area of ​​the catalyst and provides more active sites. By adjusting the valence state of the OER catalyst, the conductivity and corrosion resistance of the catalyst are enhanced, further improving the OER catalytic efficiency. The OER catalyst provided in this disclosure not only has highly efficient OER catalytic performance, but also exhibits excellent stability, and can work stably in acidic media for a long time.

[0028] The oxygen evolution reaction catalyst provided in this disclosure is not only applicable to electrochemical oxygen pumps, but also has the potential for application in other acidic media, such as proton exchange membrane electrolyzers, providing new possibilities for the development of new energy technologies. Attached Figure Description

[0029] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0030] Figure 1 A scanning electron microscope image of the oxygen evolution reaction catalyst provided in Embodiment 1 of this disclosure is shown;

[0031] Figure 2 A scanning electron microscope image of the oxygen evolution reaction catalyst provided in Comparative Example 1 of this disclosure is shown;

[0032] Figure 3Transmission electron microscopy (TEM) images of the oxygen evolution reaction catalyst provided in Embodiment 1 of this disclosure are shown.

[0033] Figure 4 Transmission electron microscopy images of the oxygen evolution reaction catalyst provided in Comparative Example 1 of this disclosure are shown.

[0034] Figure 5 XRD images of the oxygen evolution reaction catalysts provided in Example 1 and Comparative Example 1 of this disclosure are shown;

[0035] Figure 6 The polarization curves of the oxygen evolution reaction catalysts provided in Example 1, Comparative Example 1, and Comparative Example 2 of this disclosure are shown.

[0036] Figure 7 The diagram shows the oxygen production effect of the assembled membrane electrode of the oxygen evolution reaction catalyst provided in Embodiment 1 of this disclosure;

[0037] Figure 8 The oxygen production test curves of the oxygen pump assembled using the oxygen evolution reaction catalysts provided in Example 1 and Comparative Example 1 of this disclosure are shown. Detailed Implementation

[0038] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The term "comprising" as used herein indicates the presence of features, steps, or operations, but does not exclude the presence or addition of one or more other features.

[0040] When using expressions such as "at least one of A, B, and C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). When using expressions such as "at least one of A, B, or C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0041] Due to the scarcity and high price of iridium resources, how to reduce its dosage and improve the specific activity of the catalyst while ensuring its high catalytic performance has become a hot research topic.

[0042] In realizing the concept disclosed herein, it was discovered that by introducing transition metals such as ruthenium and tungsten to prepare ternary or multi-component composite oxides, the performance of iridium-based catalysts can be improved. Ruthenium and tungsten can not only regulate the electronic structure of iridium, but also enhance the conductivity and corrosion resistance of the catalyst, thereby further improving the OER catalytic efficiency. At the same time, introducing alkali metal nitrates as fluxes and carbon-nitrogen materials as regulating materials can promote the formation of oxygen evolution reaction catalysts with nanosheet structures.

[0043] Specifically, according to one aspect of the present disclosure, a method for preparing an oxygen evolution reaction catalyst is provided, comprising: calcining a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate and carbon-nitrogen material in air to obtain an oxygen evolution reaction catalyst.

[0044] According to embodiments of this disclosure, a ternary design of iridium, ruthenium, and tungsten salts optimizes the charge transport pathway, thereby improving electrocatalytic performance and stability. By introducing abundant ruthenium and tungsten, dependence on scarce and expensive iridium resources is reduced while maintaining the catalyst's high catalytic performance. The oxygen evolution reaction catalyst provided by embodiments of this disclosure is not only environmentally friendly but also helps reduce material costs and improve the sustainable use of resources.

[0045] According to embodiments of this disclosure, the microstructure of the oxygen evolution reaction (OER) catalyst is optimized by adding carbonitridium materials. These materials not only effectively prevent catalyst agglomeration but also effectively regulate the catalyst's microstructure by consuming local oxygen during air calcination, exposing more active sites and thus enhancing the catalyst's electrocatalytic activity. Furthermore, the carbonitridium materials can adjust the catalyst's valence state and stability during sintering. During air calcination, they effectively consume local oxygen inside and around the catalyst, regulating its valence state, enhancing its conductivity and corrosion resistance, and further improving OER catalytic efficiency.

[0046] According to embodiments of this disclosure, alkali metal nitrates act as auxiliary oxidants and solid-phase catalyst supports, contributing to the formation of a uniform catalyst structure.

[0047] According to embodiments of this disclosure, a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitriding material is calcined in air. During calcination, the alkali metal nitrate acts as a flux, and the carbonitriding material acts as a regulating material, promoting the formation of an oxygen evolution reaction catalyst with a nanosheet structure. Furthermore, the carbonitriding material can adjust the valence state and stability of the catalyst during sintering, which is beneficial to the conductivity of the material. The preparation method provided by the embodiments of this disclosure is simplified and conducive to large-scale production and application.

[0048] According to the embodiments of this disclosure, this disclosure does not limit the types of iridium salts, ruthenium salts, and tungsten salts. Any salt that can be obtained by calcination reaction to produce metals and their oxides is within the scope of consideration of this disclosure.

[0049] Preferably, the iridium salt is selected from one or more of chloroiridium acid, chloroiridium acid hydrate, and iridium nitrate. Preferably, the ruthenium salt is selected from one or more of trinitronitrosylruthenium, hydrated ruthenium trichloride, ruthenium trichloride, and ruthenium dichloride. Preferably, the tungsten salt is selected from one or more of tungsten chloride, oxide, or alkali metal tungsten salt.

[0050] According to the embodiments of this disclosure, this disclosure does not limit the type of alkali metal nitrate, and any alkali metal nitrate that can be used as a reaction medium in the molten salt process is within the scope of this disclosure.

[0051] Preferably, the alkali metal nitrate is selected from one or more of sodium nitrate, potassium nitrate, and lithium nitrate. Preferred alkali metal nitrates, as molten salts, possess advantages such as high boiling point, low viscosity, high volumetric heat, and chemical stability, ensuring the smooth progress of the calcination reaction.

[0052] According to the embodiments of this disclosure, this disclosure does not limit the type of carbonitriding material, and any carbonitriding material that can react and consume oxygen during the calcination process is within the scope of this disclosure.

[0053] Preferably, the carbon-nitrogen material is selected from one or more of melamine, urea, and metal-organic framework materials.

[0054] According to embodiments of this disclosure, the preparation method of mixtures of iridium salts, ruthenium salts, tungsten salts, alkali metal nitrates, and carbonitriding materials is not limited. Mixtures of iridium salts, ruthenium salts, tungsten salts, alkali metal nitrates, and carbonitriding materials can be obtained by solution mixing or by solid mixing. Preferably, mixtures of iridium salts, ruthenium salts, tungsten salts, alkali metal nitrates, and carbonitriding materials are obtained by solution mixing.

[0055] According to embodiments of this disclosure, a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitriding material is prepared by heating a dispersion containing iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitriding material until the solvent in the dispersion evaporates, thereby obtaining a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitriding material.

[0056] According to embodiments of this disclosure, iridium salts, ruthenium salts, tungsten salts, alkali metal nitrates, and carbon-nitrogen materials can be uniformly mixed through solution mixing, which helps to form an oxygen evolution reaction catalyst with a nanosheet structure.

[0057] According to embodiments of this disclosure, in a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitridium material, the molar ratio of iridium salt to ruthenium salt is 1:(0.1~10), preferably 1:(1~5). Specifically, in a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitridium material, the molar ratio of iridium salt to ruthenium salt can be 1:0.1, 1:0.2, 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, or 1:10.

[0058] According to embodiments of this disclosure, in a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitridium material, the molar ratio of the sum of iridium salt and ruthenium salt to tungsten salt is 1:(0.01~0.20), preferably 1:(0.05~0.15). Specifically, in a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitridium material, the molar ratio of the sum of iridium salt and ruthenium salt to tungsten salt can be 1:0.01, 1:0.02, 1:0.05, 1:0.10, 1:0.12, 1:0.15, 1:0.18, or 1:0.20.

[0059] According to embodiments of this disclosure, by precisely controlling the ratio of iridium (Ir), ruthenium (Ru), and tungsten (W), a significant improvement in OER catalytic performance in acidic media is achieved.

[0060] According to embodiments of this disclosure, in a mixture of iridium salts, ruthenium salts, tungsten salts, alkali metal nitrates, and carbonitridium materials, the molar ratio of the sum of iridium salts, ruthenium salts, and tungsten salts to alkali metal nitrates is (1-10):100, preferably (4-6):100. Specifically, in a mixture of iridium salts, ruthenium salts, tungsten salts, alkali metal nitrates, and carbonitridium materials, the molar ratio of the sum of iridium salts, ruthenium salts, and tungsten salts to alkali metal nitrates can be 1:100, 2:100, 3:100, 4:100, 5:100, 6:100, 7:100, 8:100, 9:100, or 10:100.

[0061] According to embodiments of this disclosure, a suitable proportion of alkali metal nitrates can provide the necessary reaction environment to promote the calcination reaction.

[0062] According to embodiments of this disclosure, in a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitriding material, the mass ratio of carbonitriding material to alkali metal nitrate is 1:(50~1000), preferably 1:(100~300). Specifically, in a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbonitriding material, the mass ratio of carbonitriding material to alkali metal nitrate can be 1:50, 1:100, 1:200, 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900, or 1:1000.

[0063] According to embodiments of this disclosure, the appropriate amount of carbon and nitrogen materials added can effectively prevent catalyst agglomeration, and the microstructure and valence state of the catalyst can be effectively controlled by consuming local oxygen during air calcination.

[0064] According to embodiments of this disclosure, the calcination temperature is 300~700℃, preferably 350~400℃. Specifically, the calcination temperature can be 300℃, 350℃, 370℃, 400℃, 450℃, 500℃, 600℃, or 700℃.

[0065] According to embodiments of this disclosure, the calcination time is 1 to 6 hours, preferably 2 to 3 hours. Specifically, the calcination time can be 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours.

[0066] According to the embodiments of this disclosure, if the calcination temperature is too low, the reaction cannot proceed; if the calcination temperature is too high, it is not conducive to the formation of nanosheet structures. Appropriate calcination temperature and time can ensure the smooth progress of the calcination reaction and ensure that the prepared oxygen evolution reaction catalyst has a nanosheet structure.

[0067] According to embodiments of this disclosure, the heating rate for calcination is 1~10°C / min, preferably 4~6°C / min. Specifically, the heating rate for calcination can be 1°C / min, 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, or 10°C / min, preferably 5°C / min.

[0068] According to embodiments of this disclosure, a dispersion containing iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbon-nitrogen material is prepared by the following method: mixing a solution containing iridium salt and a solution containing ruthenium salt to obtain a first mixture; adding an alkali metal nitrate to the first mixture to obtain a second mixture; and adding a solution containing tungsten salt and a carbon-based material to the second mixture to obtain a dispersion.

[0069] According to embodiments of this disclosure, a stepwise mixing method can make the dispersion more uniform, which is beneficial to the formation of an oxygen evolution reaction catalyst with a nanosheet structure.

[0070] According to embodiments of this disclosure, in solutions containing iridium salts, ruthenium salts, and tungsten salts, the solvent can be selected based on the type of metal salt. For example, for WCl6, the solution containing tungsten salt can be an ethanol solution containing WCl6.

[0071] According to embodiments of this disclosure, the concentration of the solution containing iridium salt is 0.01~1.00 mol / L.

[0072] According to embodiments of this disclosure, the concentration of the solution containing ruthenium salt is 0.02~2.00 mol / L.

[0073] According to embodiments of this disclosure, the concentration of the solution containing tungsten salt is 0.001~0.5 mol / L.

[0074] According to an embodiment of another aspect of this disclosure, an oxygen evolution reaction catalyst prepared by the above-described preparation method is provided.

[0075] The oxygen evolution reaction (OER) catalyst provided in this disclosure has a nanosheet structure, which significantly increases the specific surface area of ​​the catalyst and provides more active sites. By adjusting the valence state of the OER catalyst, the conductivity and corrosion resistance of the catalyst are enhanced, further improving the OER catalytic efficiency. The OER catalyst provided in this disclosure not only has highly efficient OER catalytic performance, but also exhibits excellent stability, and can work stably in acidic media for a long time.

[0076] According to an embodiment of another aspect of this disclosure, the application of the above-described oxygen evolution reaction catalyst in the field of electrochemical oxygen production is provided.

[0077] The oxygen evolution reaction catalyst provided in this disclosure is not only applicable to electrochemical oxygen pumps, but also has the potential for application in other acidic media, such as proton exchange membrane electrolyzers, providing new possibilities for the development of new energy technologies.

[0078] The following detailed description provides several specific embodiments to illustrate the technical solutions of this disclosure. It should be noted that the specific embodiments described below are merely examples and are not intended to limit this disclosure.

[0079] Example 1

[0080] This embodiment provides a method for preparing an oxygen evolution reaction catalyst, including the following steps:

[0081] (1) Solution preparation

[0082] H₂IrCl₆·6H₂O and RuCl₃·xH₂O were dissolved in deionized water to obtain 0.1 mol / L iridium salt solution and 0.2 mol / L ruthenium salt solution, respectively.

[0083] WCl6 was dissolved in ultra-dry ethanol to obtain a 0.05 mol / L tungsten salt solution.

[0084] (2) Preparation of dispersion

[0085] Mix 8 mL of iridium salt solution and 5 mL of ruthenium salt solution, and sonicate for 30 minutes to obtain the first mixture.

[0086] Add NaNO3 in a ratio of 1:10 to the total amount of metal to the first mixture, and sonicate until completely dissolved to obtain the second mixture.

[0087] Add melamine (at a mass ratio of 1:100 to NaNO3) as a carbon-nitrogen material and 1 mL of tungsten salt solution to the second mixture, mix well, and obtain a dispersion.

[0088] (3) Solvent evaporation and grinding

[0089] The dispersion was placed in a vacuum drying oven and heated at 60°C until the solvent was completely evaporated, yielding a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbon-nitrogen materials.

[0090] A mixture of iridium salts, ruthenium salts, tungsten salts, alkali metal nitrates, and carbonitridium materials is ground into a fine powder.

[0091] (4) Calcination

[0092] The powder was loaded into a ceramic boat and placed in a tube furnace. The temperature was increased to 400°C at a rate of 5°C / min and maintained for 3 hours.

[0093] (5) Post-processing

[0094] After calcination, the sample was cooled to room temperature and washed repeatedly with deionized water until the filtrate was colorless.

[0095] The washed sample was dried in a vacuum drying oven at 60°C for 12 hours to obtain the oxygen evolution reaction catalyst.

[0096] Example 2

[0097] This embodiment provides a method for preparing an oxygen evolution reaction catalyst, including the following steps:

[0098] (1) Solution preparation

[0099] H₂IrCl₆·6H₂O and RuCl₃·xH₂O were dissolved in deionized water to obtain 0.05 mol / L iridium salt solution and 0.3 mol / L ruthenium salt solution, respectively.

[0100] WCl6 was dissolved in ultra-dry ethanol to obtain a 0.05 mol / L tungsten salt solution.

[0101] (2) Preparation of dispersion

[0102] Mix 5 mL of iridium salt solution and 8 mL of ruthenium salt solution, and sonicate for 30 minutes to obtain the first mixture.

[0103] Add NaNO3 in a ratio of 1:8 to the total amount of metal to the first mixture, and sonicate until completely dissolved to obtain the second mixture.

[0104] Add urea (at a mass ratio of 1:200 to NaNO3) as a carbon-nitrogen material and 1 mL of tungsten salt solution to the second mixture, mix well, and obtain a dispersion.

[0105] (3) Solvent evaporation and grinding

[0106] The dispersion was placed in a vacuum drying oven and heated at 60°C until the solvent was completely evaporated, yielding a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbon-nitrogen materials.

[0107] A mixture of iridium salts, ruthenium salts, tungsten salts, alkali metal nitrates, and carbonitridium materials is ground into a fine powder.

[0108] (4) Calcination

[0109] The powder was loaded into a ceramic boat and placed in a tube furnace. The temperature was increased to 350°C at a rate of 5°C / min and maintained for 2 hours.

[0110] (5) Post-processing

[0111] After calcination, the sample was cooled to room temperature and washed repeatedly with deionized water until the filtrate was colorless.

[0112] The washed sample was dried in a vacuum drying oven at 60°C for 12 hours to obtain the oxygen evolution reaction catalyst.

[0113] Example 3

[0114] This embodiment provides a method for preparing an oxygen evolution reaction catalyst, including the following steps:

[0115] (1) Preparation of dispersion

[0116] H₂IrCl₆·6H₂O, RuCl₃·xH₂O, WCl₆, NaNO₃, and melamine were added to deionized water and ultrasonically mixed to obtain a dispersion containing iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate, and carbon-nitrogen materials. The amounts of H₂IrCl₆·6H₂O, RuCl₃·xH₂O, WCl₆, NaNO₃, and melamine added were the same as in Example 1.

[0117] The dispersion was subjected to solvent evaporation and grinding, calcination and post-treatment to obtain the oxygen evolution reaction catalyst. The specific steps are as described in Example 1 and will not be repeated here.

[0118] Comparative Example 1

[0119] This comparative example provides a method for preparing an oxygen evolution reaction catalyst. Referring to Example 1, the difference is that in step (2), only sodium nitrate is added, and no carbon or nitrogen materials are added.

[0120] Comparative Example 2

[0121] This comparative example provides a method for preparing an oxygen evolution reaction catalyst. Referring to Example 1, the difference is that in step (2), only carbon and nitrogen materials are added, and sodium nitrate is not added.

[0122] The oxygen evolution reaction catalysts provided in Example 1 and Comparative Example 1 were examined by scanning electron microscopy (SEM), and the SEM images are shown below. Figure 1 and Figure 2 As shown. By Figure 1 and Figure 2 Analysis shows that the oxygen evolution reaction catalyst provided in this embodiment is smaller in size, thus exposing more active sites, which is more conducive to the reaction.

[0123] Transmission electron microscopy (TEM) was performed on the oxygen evolution reaction catalysts provided in Example 1 and Comparative Example 1. The TEM images are shown below. Figure 3 and Figure 4 As shown. By Figure 3 and Figure 4Analysis shows that the oxygen evolution reaction catalyst provided in Example 1 of this disclosure has a layered structure with a thickness of nanometers, while the oxygen evolution reaction catalyst provided in Comparative Example 1 has significantly thicker particles and more obvious agglomeration.

[0124] The oxygen evolution reaction catalysts provided in Example 1 and Comparative Example 1 were analyzed by X-ray diffraction (XRD), and the results are as follows: Figure 5 As shown. By Figure 5 Analysis shows that the oxygen evolution reaction catalyst prepared without the addition of carbon and nitrogen materials (Comparative Example 1) clearly has a mixed oxide peak shape, while the oxygen evolution reaction catalyst prepared with the addition of carbon and nitrogen materials (Example 1) has a significant difference in metal valence states, with pure metal diffraction peaks clearly appearing at around 40 degrees. This indicates that there are certain low-valence metals (e.g., zero-valence metals) in the catalyst.

[0125] The oxygen evolution reaction (OER) catalysts provided in Example 1, Comparative Examples 1 and 2 were tested. The test conditions are as follows:

[0126] Electrolyte: The electrolyte used is a 1.0 mol / L H2SO4 solution, ensuring that the test is conducted in an acidic environment;

[0127] Electrode configuration: A three-electrode system is adopted, including a working electrode (catalyst), a counter electrode (platinum electrode), and a reference electrode (Ag / AgCl).

[0128] Polarization curve measurement: The polarization curve was measured using the linear voltammetry (LSV) method at a scan rate of 1-5 mV / s to ensure that the electrode surface was basically in a steady state.

[0129] The polarization curves obtained from the test are as follows Figure 6 As shown. By Figure 6 Analysis shows that in Embodiment 1 of this disclosure, at 10 mA / cm 2 The optimal overpotential is found below this value.

[0130] The oxygen evolution reaction catalysts provided in Example 1 and Comparative Example 1 were coated onto a proton exchange membrane (acidic) using a conventional membrane electrode assembly (MEA) process, serving as the anode of the oxygen pump. A standard platinum-carbon catalyst was used as the cathode for comparison, with a reaction area of ​​4 cm × 4 cm. The catalyst-coated MEAs were then assembled to form a complete oxygen pump system.

[0131] The anodic reaction is:

[0132]

[0133] The cathode reaction is:

[0134]

[0135] The oxygen pump was tested in air, and the oxygen production efficiency, concentration, and stability were recorded under different voltages. The oxygen production effect was as follows: Figure 7 As shown, the oxygen production concentration is 99.9%. The oxygen production test results are as follows... Figure 8 As shown. By Figure 8 Analysis shows that the oxygen pump assembled using the oxygen evolution reaction catalyst provided in Example 1 can operate stably for more than 120 hours at 1.5V, demonstrating excellent catalytic performance and stability. In contrast, the oxygen pump assembled using the oxygen evolution reaction catalyst provided in Comparative Example 1 experiences a significant voltage increase after 50 hours, rendering it unable to effectively carry out the catalytic reaction.

[0136] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A method for preparing an oxygen evolution reaction catalyst, characterized in that: include: The mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate and carbon-nitrogen material is calcined in air to obtain an oxygen evolution reaction catalyst.

2. The preparation method according to claim 1, characterized in that: The mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate and carbon nitrogen material is prepared by the following method: A dispersion containing iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate and carbon nitrogen material is heated until the solvent in the dispersion evaporates to obtain a mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate and carbon nitrogen material.

3. The preparation method according to claim 1 or 2, characterized in that: In the mixture of iridium salt, ruthenium salt, tungsten salt, alkali metal nitrate and carbonitride material: The molar ratio of the iridium salt to the ruthenium salt is 1:(0.1-10); The molar ratio of the sum of the iridium salt and the ruthenium salt to the tungsten salt is 1:(0.01-0.20); The molar ratio of the sum of the iridium salt, the ruthenium salt and the tungsten salt to the alkali metal nitrate is (1-10):100; The mass ratio of the carbon-nitrogen material to the alkali metal nitrate is 1:(50-1000).

4. The preparation method according to claim 1 or 2, characterized in that: The calcination temperature is 300-700°C; The calcination time is 1 to 6 hours.

5. The preparation method according to claim 4, characterized in that: The heating rate of the calcination is 1-10°C / min; The calcination temperature is 350-400°C.

6. The preparation method according to claim 1 or 2, characterized in that: The carbon-nitrogen material is selected from one or more of melamine, urea and metal-organic framework materials; The alkali metal nitrate is selected from one or more of sodium nitrate, potassium nitrate and lithium nitrate; The iridium salt is selected from one or more of chloroiridic acid, chloroiridic acid hydrate and iridium nitrate; The ruthenium salt is selected from one or more of trinitronitrosyl ruthenium, hydrated ruthenium trichloride, ruthenium trichloride and ruthenium dichloride; The tungsten salt is selected from one or more of tungsten chloride, oxide or alkali metal tungsten salt.

7. The preparation method according to claim 2, characterized in that: The dispersion containing iridium salt, ruthenium salt, tungsten salt, nitrate of alkali metal and carbon nitrogen material is prepared by the following method: Mixing a solution containing an iridium salt and a solution containing a ruthenium salt to obtain a first mixed solution; adding the alkali metal nitrate to the first mixed solution to obtain a second mixed solution; A solution containing tungsten salt and the carbon-based material are added to the second mixed liquid to obtain the dispersion.

8. The preparation method according to claim 7, characterized in that: The concentration of the solution containing the iridium salt is 0.01-1.00 mol / L; The concentration of the solution containing ruthenium salt is 0.02-2.00 mol / L; The concentration of the solution containing tungsten salt is 0.001-0.5 mol / L.

9. An oxygen evolution reaction catalyst prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The oxygen evolution reaction catalyst is a nanosheet structure.

10. Use of the oxygen evolution reaction catalyst according to claim 9 in the field of electrochemical oxygen production.

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