Ir-ruthenium oxide composite catalyst, preparation method thereof and proton exchange membrane water electrolysis device

Abstract

The application provides an iridium-ruthenium oxide composite catalyst, a preparation method thereof and a proton exchange membrane water electrolysis device, and relates to the field of hydrogen production by water electrolysis. The preparation method of the iridium-ruthenium oxide composite catalyst comprises the following steps: mixing sodium nitrate, ruthenium chloride and water to prepare a mixed solution, and then drying and grinding to obtain a mixture; placing the mixture on the surface of a nickel foil, using a joule heating device for first heating, and then cooling to obtain ruthenium oxide; mixing the ruthenium oxide, cetyltrimethylammonium bromide and ethylene glycol, and ultrasonic dispersion to obtain a ruthenium oxide solution; mixing the ruthenium oxide solution, H2IrCl6 and potassium hydroxide, adjusting the pH of the system to alkaline, and then second heating to reflux and constant temperature reaction, and then solid-liquid separation and washing of the reaction product to obtain the iridium-ruthenium oxide composite catalyst. The iridium-ruthenium oxide composite catalyst provided by the application has high activity and high stability, and has high water electrolysis efficiency.

Description

Technical Field

[0001] This application relates to the field of hydrogen production by water electrolysis, and in particular to an iridium-ruthenium oxide composite catalyst, its preparation method, and a proton exchange membrane water electrolysis device. Background Technology

[0002] In proton exchange membrane electrolysis (PEMWE) technology, the oxygen evolution reaction (OER) is a crucial half-reaction. Its kinetics are slow, requiring highly efficient catalysts to reduce overpotential and improve electrolysis efficiency. Currently, iridium-based catalysts are the mainstream anodic OER catalysts in this field; however, iridium abundance is extremely low, making it difficult to meet the demands of future large-scale commercial applications. Ruthenium-based catalysts, with their high intrinsic activity, show great potential in PEMWE. However, they are prone to oxidative dissolution during the reaction, leading to rapid deactivation, which is a major challenge restricting their commercial application.

[0003] Therefore, developing ruthenium-based catalysts with both high activity and high stability is of great significance for promoting the large-scale development of PEMWE technology. Summary of the Invention

[0004] The purpose of this application is to provide an iridium-ruthenium oxide composite catalyst, its preparation method, and a proton exchange membrane water electrolysis device to solve the above-mentioned problems.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] A method for preparing an iridium-ruthenium oxide composite catalyst, comprising:

[0007] A mixed solution was prepared by mixing sodium nitrate, ruthenium chloride, and water, and then dried and ground to obtain a mixture.

[0008] The mixture was placed on the surface of a nickel foil, first heated using a Joule heating device, and then cooled to obtain ruthenium oxide;

[0009] Ruthenium oxide, hexadecyltrimethylammonium bromide, and ethylene glycol were mixed and ultrasonically dispersed to obtain a ruthenium oxide solution. The ruthenium oxide solution, H2IrCl6, and potassium hydroxide were mixed to obtain an alkaline mixture. The mixture was then heated to reflux and kept at a constant temperature. The reaction product was separated into solid and liquid phases and washed to obtain the iridium-ruthenium oxide composite catalyst.

[0010] Sodium nitrate, when heated to a molten salt state, acts as an oxidizing agent to oxidize ruthenium chloride to ruthenium oxide. The reaction equation is as follows:

[0011] RuCl3 + 3NaNO3 (high temperature) = RuO2 + 3NaCl + 3NO2↑ + 1 / 2O2↑.

[0012] This is the Adams molten salt method, which has high synthesis efficiency and high purity.

[0013] The dispersant hexadecyltrimethylammonium bromide mainly plays a dispersing role, improving the dispersibility of ruthenium oxide in ethylene glycol and preventing its excessive aggregation from affecting the adhesion and dispersion effect of iridium nanoclusters.

[0014] Ethylene glycol acts as a solvent and reducing agent, primarily reducing chloroiridic acid to elemental iridium. As a weak reducing agent, its slow reduction effect facilitates the dispersion of iridium on the ruthenium oxide surface, reducing the degree of agglomeration of iridium nanoparticles.

[0015] Ruthenium oxide carries a positive charge on its surface, and can adsorb negatively charged IrCl6 using the principle of electrostatic adsorption. 4- This allows it to adhere firmly to the ruthenium oxide surface, and to be more evenly dispersed in subsequent reduction steps.

[0016] Preferably, the mass ratio of sodium nitrate to ruthenium chloride is (20-50):1.

[0017] Preferably, the drying temperature is 60-80°C;

[0018] And / or,

[0019] The Joule heating device has a current of 55-60A and a heating time of 20s.

[0020] Preferably, the temperature of the first heating is 300-500℃;

[0021] And / or,

[0022] The heating rate is 14-24 K / s;

[0023] And / or,

[0024] The cooling rate is 4.6-8 K / s.

[0025] The rapid heating and cooling high-temperature thermal shock technology utilizes a non-equilibrium high-temperature environment to induce the overflow of oxygen atoms to form oxygen vacancies, and obtains ultrafine-sized nano-ruthenium oxide by limiting grain growth time and thermal stress fragmentation mechanism.

[0026] Preferably, the ruthenium oxide has a particle size of 2.5-5.5 nm.

[0027] Preferably, the molar ratio of ruthenium oxide, hexadecyltrimethylammonium bromide, H2IrCl6 and potassium hydroxide is 10:10-100:2-5:2.

[0028] Preferably, the pH of the alkaline mixture is 8-12.

[0029] Preferably, the temperature of the isothermal reaction is 130-150℃.

[0030] This application also provides an iridium-ruthenium oxide composite catalyst, which is prepared using the method described above.

[0031] This application also provides a proton exchange membrane water electrolysis device, including the aforementioned iridium-ruthenium oxide composite catalyst.

[0032] Compared with the prior art, the beneficial effects of this application include:

[0033] The method for preparing the iridium-ruthenium oxide composite catalyst provided in this application employs the Adams molten salt method, utilizing a Joule heating device and a high-temperature thermal shock technique to rapidly heat and cool the ruthenium oxide, resulting in ruthenium oxide with abundant oxygen vacancies and ultrafine particle size. Compared with commercial ruthenium oxide and ruthenium oxide synthesized via a muffle furnace, the preparation cycle is shorter and the obtained ruthenium oxide particle size is smaller. Iridium clusters are grown on the surface of the obtained ruthenium oxide through a wet chemical-solvent thermal reduction method, forming a stable heterostructure. Constructing heterostructures is an effective strategy for controlling the local electronic environment, stabilizing the structure through interfacial charge transfer, and effectively mitigating Ru oxidation and dissolution. The construction of heterostructures often relies on traditional heat treatment processes. The high-temperature thermal shock technique used in this application can rapidly synthesize oxygen-vacancy-rich ultrafine nanoparticles through non-equilibrium thermodynamics, which is simple and efficient.

[0034] The iridium-ruthenium oxide composite catalyst provided in this application belongs to the category of oxygen-vacancy-rich Ir / RuO2 ultrafine nanoparticle catalysts, exhibiting excellent OER performance at 10 mA / cm². 2 The overpotential at current density is only 150mV, and it can operate stably for over 500 hours with a voltage decay rate of only 77µV / h.

[0035] The proton exchange membrane water electrolysis device provided in this application exhibits excellent performance, achieving 1A / cm at a battery voltage of 1.6V. 2 Industrial-grade current density, and at 1 A / cm 2 It can operate stably for more than 100 hours at current density, which significantly improves the efficiency of water electrolysis.

[0036] This application effectively alleviates the oxidative dissolution problem of ruthenium-based catalysts through a unique catalyst design and mechanism of action, while improving catalytic activity. It provides an effective way to improve the performance of ruthenium-based catalysts and helps to promote the commercialization of proton exchange membrane water electrolysis technology. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0038] Figure 1 The HTS curve for the synthesis of ruthenium oxide in Example 1;

[0039] Figure 2 Linear sweep voltammetry curves for different ruthenium oxides;

[0040] Figure 3 Electron paramagnetic resonance spectra of different ruthenium oxides;

[0041] Figure 4 TEM images of different ruthenium oxides;

[0042] Figure 5 Particle size distribution of different ruthenium oxides;

[0043] Figure 6 Linear sweep voltammetry curves of RuO2 obtained in Example 1 and iridium-ruthenium oxide composite catalysts obtained in Examples 1, 6 to 8;

[0044] Figure 7 Linear sweep voltammetry curves of RuO2 obtained in Example 1 and the iridium-ruthenium oxide composite catalysts obtained in Examples 1 and 9 are shown.

[0045] Figure 8 These are TEM images and particle size distribution diagrams of the iridium-ruthenium oxide composite catalyst obtained in Example 1 at different magnifications.

[0046] Figure 9 The chronopotential test curves of the ruthenium oxide and iridium-ruthenium oxide composite catalyst obtained in Example 1 are shown.

[0047] Figure 10 The linear sweep voltammetric curves of RuO2 obtained in Example 1, Comparative Example 1 and Comparative Example 2, the iridium-ruthenium oxide composite catalyst obtained in Example 1 and Comparative Example 2, and the iridium provided in Comparative Example 3 are shown.

[0048] Figure 11 Linear sweep voltammetric curves of the ruthenium oxide obtained in Example 1 and the iridium-ruthenium oxide composite catalysts obtained in Comparative Examples 4 to 6;

[0049] Figure 12 The PEMWE polarization curves of the ruthenium oxide and iridium-ruthenium oxide composite catalyst obtained in Example 1, the ruthenium oxide provided in Comparative Example 1 and the iridium oxide provided in Comparative Example 7 as anode catalysts, and commercial Pt / C as cathode catalysts were obtained in deionized water at 60°C.

[0050] Figure 13 Using the ruthenium oxide and iridium-ruthenium oxide composite catalyst obtained in Example 1 as the anode catalyst and commercial Pt / C as the cathode catalyst, the catalyst was reacted in deionized water at 60°C at 1 A / cm². 2 The chronopotential curve obtained under constant current density. Detailed Implementation

[0051] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0052] Example 1

[0053] This embodiment provides an iridium-ruthenium oxide composite catalyst, the preparation method of which includes the following steps:

[0054] Step 1: Preparation of oxygen-vacancy-rich ultrafine ruthenium oxide nanoparticles. 5g NaNO3 and 100mg RuCl3•xH2O were mixed and dispersed in 30mL deionized water and dried overnight in an oil bath at 80℃. The dried mixture was then ground for 1 hour, and 1g of the mixture was evenly spread on a 3×5cm substrate. 2 A nickel foil, 0.2 cm thick, was connected to two electrodes of a DC power supply in a Joule heating apparatus. It was heated at 60 A for 20 s (350 °C) at a heating rate of 16.5 K / s and a cooling rate of 3.9 K / s, yielding ruthenium oxide (denoted as RuO2-HTS 300 °C) with abundant oxygen vacancies and ultrafine particle size. The HTS curve of the ruthenium oxide synthesis is shown below. Figure 1 As shown.

[0055] Step 2: Growth of iridium clusters on the ruthenium oxide surface. 10 mg RuO2 was used as a seed crystal and mixed with 0.1 g cetyltrimethylammonium bromide (CTAB) and dispersed in 30 mL of ethylene glycol. The mixture was sonicated for 2 hours to obtain a uniformly dispersed ruthenium oxide solution. 2.5 mL of 0.01 MIR solution was then added to the above solution. 4+ Add 1M KOH to (H2IrCl6) to adjust the pH of the solution to 8. Place the above mixed solution in an oil bath, heat and stir using a reflux device, and maintain the temperature for 1 hour at 150℃. After the reaction, separate the solid and liquid. Wash the solid three times with acetone, ethanol, and deionized water in sequence to obtain Ir / RuO2, which is the iridium-ruthenium oxide composite catalyst.

[0056] Example 2

[0057] Unlike Example 1, the Joule device uses a heating current of 58A, a heating time of 20s, and a temperature of 300°C.

[0058] Example 3

[0059] Unlike Example 1, the Joule heating device uses a heating current of 62A, a heating time of 20s, and a temperature of 400°C.

[0060] Example 4

[0061] Unlike Example 1, the Joule heating device uses a heating current of 65A, a heating time of 20s, and a temperature of 450°C.

[0062] Example 5

[0063] Unlike Example 1, the Joule device uses a heating current of 67A for 20s and a temperature of 500°C.

[0064] Example 6

[0065] Unlike Example 1, in the second step, the pH of the solution was adjusted to 9.

[0066] Example 7

[0067] Unlike Example 1, in the second step, the pH of the solution was adjusted to 10.

[0068] Example 8

[0069] Unlike Example 1, in the second step, the pH of the solution was adjusted to 12.

[0070] Example 9

[0071] Unlike Example 1, in the second step, the reaction temperature is 130°C.

[0072] Comparative Example 1

[0073] Commercial ruthenium oxide (purchased from Maclean's, denoted as Com RuO2) was used as a reference.

[0074] Comparative Example 2

[0075] Unlike Example 1, the dried mixture was ground for 1 hour, and then the mixture was treated in a muffle furnace at 350°C with a heating rate of 10°C / min and a holding time of 30 min to obtain ruthenium oxide (denoted as RuO2-MFC).

[0076] The ruthenium oxides obtained in Examples 1 to 5, Comparative Examples 1 and 2 were tested, and linear sweep voltammetric curves of ruthenium oxides under different synthesis temperatures and methods were obtained, as shown below. Figure 2As shown. Linear sweep voltammetry curves were measured using a Chenhua 760 electrochemical workstation. The test voltage range was 0.6 V–1.2 V, and the scan rate was 5 mV / s. First, a catalyst slurry was prepared. Before preparing the working electrode, 2 mg of Ir / RuO2-HTS catalyst was weighed and added sequentially to 450 μL of anhydrous ethanol, 50 μL of ultrapure water, and 20 μL of 5% Nafion solution. The mixture was ultrasonically dispersed for 2 hours to obtain a uniformly dispersed ink solution. A certain amount of catalyst ink was then added (different catalysts maintained the same noble metal loading, 0.3 mg / cm³). 2 The electrode was drop-coated onto a polished working electrode (GC glassy carbon electrode, 5 mm in diameter, 0.196 cm² area). 2 Air dry naturally for later use. The area activity and mass activity are normalized based on the obtained current, taking into account GCE and the area of ​​the noble metal loading. All electrochemical experiments were conducted in a standard three-electrode half-cell system at room temperature. A glassy carbon electrode with a catalyst was used as the working electrode, a platinum sheet as the counter electrode, mercury / mercurous sulfate as the reference electrode, and 0.5 M H₂SO₄ as the electrolyte. The electrode potential of the reference electrode was pre-corrected and converted to the reversible hydrogen electrode potential (vs RHE). The conversion formula is:

[0077] E(vs.RHE)=E(vs.SCE)+0.652V+0.0591*pH V (1)

[0078] Wherein, ESCE is the voltage value obtained in the test, and 0.652V is the zero current potential value obtained after calibrating the SCE electrode with a standard hydrogen electrode before the test.

[0079] from Figure 1 It can be seen that the HTS temperature range is 300-500℃, and the optimal HTS temperature is 350℃. At this temperature, ruthenium oxide exhibits a flux of 10 mA / cm². 2 The overpotential was 167 mV, which is better than that of the muffle furnace sample and the commercial ruthenium oxide sample.

[0080] It should be noted that, in the actual heating process, under the same conditions, the sample heated at 300°C in Example 2 was not fully heated and the sodium nitrate oxidant was not completely melted. Although it had good performance, its stability was poor. Through comparison of multiple factors (heating conditions, activity, and stability), the optimal temperature was selected as 350°C.

[0081] The ruthenium oxide obtained in Example 1, Comparative Example 1, and Comparative Example 2 was tested, and electron paramagnetic resonance spectra were obtained, as shown below. Figure 3 As shown (the black curve overlaps with the purple curve).

[0082] Depend on Figure 3It can be seen that the oxygen vacancy concentration of ruthenium oxide prepared by different synthesis methods is different. EPR test showed that the ruthenium oxide synthesized by HTS has the highest oxygen vacancy concentration, indicating that the HTS synthesis method can introduce more oxygen vacancies, which is beneficial to charge transport in the OER process.

[0083] The ruthenium oxide obtained from Example 1, Comparative Example 1, and Comparative Example 2 was tested, and the resulting TEM images are shown below. Figure 4 As shown, the obtained particle size distribution diagram is as follows: Figure 5 As shown.

[0084] Commercial ruthenium oxide particles are relatively large, while ruthenium oxide synthesized in a muffle furnace and by HTS has a relatively smaller particle size and is more uniformly dispersed. The average particle size of commercial ruthenium oxide is 18.4 nm, that of muffle furnace-synthesized ruthenium oxide is 4.4 nm, and that of HTS-synthesized ruthenium oxide is 3.5 nm. This indicates that the HTS synthesis method is advantageous for synthesizing ultrafine particles and avoids excessive agglomeration and secondary growth of particles.

[0085] The linear sweep voltammetric curves of RuO2 obtained in Example 1 and the iridium-ruthenium oxide composite catalysts obtained in Examples 1, 6 to 8 are shown below. Figure 6 As shown.

[0086] Depend on Figure 6 It can be seen that the optimal synthesis pH is 8, and the catalytic activity of Ir / RuO2 is improved compared with that of ruthenium oxide alone.

[0087] The linear sweep voltammetric curves of RuO2 obtained in Example 1 and the iridium-ruthenium oxide composite catalysts obtained in Examples 1 and 9 are shown below. Figure 7 As shown.

[0088] Depend on Figure 7 It can be seen that the optimal solvothermal temperature is 150℃, and the catalytic activity of Ir / RuO2 is improved compared with that of ruthenium oxide alone.

[0089] The iridium-ruthenium oxide composite catalyst obtained in Example 1 was tested, and TEM images and particle size distribution maps at different magnifications were obtained, as shown below. Figure 8 As shown, a is 200 kX, b is 500 kX, c is 2 Mx, and d is the particle size distribution.

[0090] from Figure 8 It can be seen that the 1.02 nm Ir nanoclusters are uniformly distributed on the ruthenium oxide surface, indicating the formation of a robust heterostructure interface.

[0091] The ruthenium oxide and iridium-ruthenium oxide composite catalyst obtained in Example 1 was tested at 10 mA / cm². 2 Chronopotential testing was performed at current density, and the results are as follows: Figure 9 As shown.

[0092] In 0.5 M H2SO4 electrolyte, the Ir / RuO2 catalyst at 10 mA / cm 2 It can operate stably for over 500 hours at current density with a voltage decay rate of only 77 µV / h, while the ruthenium oxide sample alone completely fails after 30 hours of operation, indicating that iridium loading helps to suppress the oxidative dissolution of Ru.

[0093] Comparative Example 3

[0094] Unlike Example 1, Ir (Ir NPs) were synthesized alone without the addition of ruthenium oxide.

[0095] The linear sweep voltammetric curves of RuO2 obtained in Example 1, Comparative Example 1, and Comparative Example 2, the iridium-ruthenium oxide composite catalysts obtained in Example 1 and Comparative Example 2, and the iridium provided in Comparative Example 3 are shown below. Figure 10 As shown.

[0096] Compared to iridium alone, ruthenium oxide synthesized in a muffle furnace and HTS alone, commercial ruthenium oxide, and Ir / RuO2-MFC samples, ruthenium oxide synthesized by HTS and then loaded with Ir (Ir / RuO2-HTS) exhibits the best catalytic activity, with an overpotential of only 150 mV at a current density of 10 mA / cm2.

[0097] Comparative Example 4

[0098] An attempt was made to synthesize a mixed catalyst of iridium oxide and ruthenium oxide. Ruthenium oxide was synthesized by HTS, and after precipitation with iridium chloride acid, it was pyrolyzed at 500℃ to form iridium oxide.

[0099] Comparative Example 5

[0100] Unlike Comparative Example 4, the pyrolysis temperature was 550℃.

[0101] Comparative Example 6

[0102] Unlike Comparative Example 4, the pyrolysis temperature was 600℃.

[0103] In 0.5 M H₂SO₄ electrolyte, the linear sweep voltammetric curves of the iridium-ruthenium oxide composite catalyst obtained in Example 1 and the iridium oxide-ruthenium oxide composite catalysts obtained in Comparative Examples 4 to 6 are as follows: Figure 11 As shown.

[0104] The effects of different pyrolysis temperatures on the catalytic activity of iridium oxide-ruthenium oxide catalysts were investigated. It was found that the catalytic activity of iridium oxide-ruthenium oxide catalysts decreased compared to iridium-ruthenium oxide composite catalysts. This may be because the secondary heat treatment caused the ruthenium oxide to re-grow thermally, leading to a further decrease in catalytic activity.

[0105] Comparative Example 7

[0106] Using commercial iridium oxide as a reference, it is denoted as Com IrO2.

[0107] The ruthenium oxide and iridium-ruthenium oxide composite catalyst obtained in Example 1, the ruthenium oxide provided in Comparative Example 1 and the iridium oxide provided in Comparative Example 7 as anode catalysts, and commercial Pt / C as cathode catalysts, were used. The PEMWE polarization curves obtained in deionized water at 60°C are shown below. Figure 12 As shown. The noble metal loading of the anode is 1 mg Ru + Ir / cm. 2 The cathode has a concentration of 0.36 mgPt / cm. 2 No IR compensation was performed on the battery voltage.

[0108] Compared to commercial ruthenium oxide, commercial iridium oxide, and ruthenium oxide synthesized by HTS alone, the Ir / RuO2 sample exhibited the best catalytic activity, reaching 1 A / cm at 60 °C. 2 The current density requires only a battery voltage of 1.6 V.

[0109] The ruthenium oxide and iridium-ruthenium oxide composite catalyst obtained in Example 1 was used as the anode catalyst, and commercial Pt / C was used as the cathode catalyst. The catalyst was reacted at 60°C in deionized water at a concentration of 1 A / cm³. 2 The chronopotential curve obtained under constant current density, as shown in the figure. Figure 13 As shown. The noble metal loading on the anode is 1 mg. Ru+Ir / cm 2 The cathode has a concentration of 0.36 mgPt / cm. 2 .

[0110] 1 A / cm 2 The Ir / RuO2 catalyst can operate stably for 100 h at the current density, while ruthenium oxide alone becomes completely ineffective after a dozen hours of operation.

[0111] Comparative Example 8

[0112] Unlike Example 1, cetyltrimethylammonium bromide was replaced with polyvinylpyrrolidone (PVP). The resulting catalyst was less active than CTAB, and PVP was not suitable for the dispersion of ruthenium oxide.

[0113] Comparative Example 9

[0114] Unlike Example 1, ethylene glycol was replaced with sodium borohydride.

[0115] Sodium borohydride, as a strong reducing agent, has a reduction rate that is too fast, causing iridium nanoparticles to agglomerate and ruthenium oxide to separate, making it impossible to form a good heterogeneous interface.

[0116] Comparative Example 10

[0117] Unlike Example 1, when H2IrCl6 was replaced with other iridium sources such as IrCl3 and Ir(acac)3, the activity decreased after loading, which is presumably due to phase separation.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing an iridium-ruthenium oxide composite catalyst, characterized in that, include: A mixed solution was prepared by mixing sodium nitrate, ruthenium chloride, and water, and then dried and ground to obtain a mixture. The mixture is placed on the surface of a nickel foil, subjected to a first heating using a Joule heating device, and then cooled to obtain ruthenium oxide; the temperature of the first heating is 300-500°C, the heating rate is 14-24 K / s, and the cooling rate is 4.6-8 K / s; Ruthenium oxide, hexadecyltrimethylammonium bromide, and ethylene glycol were mixed and ultrasonically dispersed to obtain a ruthenium oxide solution. The ruthenium oxide solution, H2IrCl6, and potassium hydroxide were mixed to obtain an alkaline mixture. The mixture was then heated to reflux and kept at a constant temperature. The reaction product was separated into solid and liquid phases and washed to obtain the iridium-ruthenium oxide composite catalyst.

2. The preparation method of the iridium-ruthenium oxide composite catalyst according to claim 1, characterized in that, The mass ratio of sodium nitrate to ruthenium chloride is (20-50):

1.

3. The preparation method of the iridium-ruthenium oxide composite catalyst according to claim 1, characterized in that, The drying temperature is 60-80℃; And / or, The Joule heating device has a current of 55-60A and a heating time of 20s.

4. The preparation method of the iridium-ruthenium oxide composite catalyst according to claim 1, characterized in that, The ruthenium oxide has a particle size of 2.5-5.5 nm.

5. The preparation method of the iridium-ruthenium oxide composite catalyst according to claim 1, characterized in that, The mass ratio of ruthenium oxide, hexadecyltrimethylammonium bromide, H2IrCl6 and potassium hydroxide is 10:10-100:2-5:

2.

6. The preparation method of the iridium-ruthenium oxide composite catalyst according to claim 1, characterized in that, The pH of the alkaline mixture is 8-12.

7. The method for preparing the iridium-ruthenium oxide composite catalyst according to any one of claims 1-6, characterized in that, The temperature of the isothermal reaction is 130-150℃.

8. An iridium-ruthenium oxide composite catalyst, characterized in that, It was prepared using the method for preparing the iridium-ruthenium oxide composite catalyst according to any one of claims 1-7.

9. A proton exchange membrane water electrolysis device, characterized in that, Including the iridium-ruthenium oxide composite catalyst as described in claim 8.

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