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

Abstract

The invention 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 through 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 nickel foil, carrying out first heating by using Joule heating equipment, and then cooling to obtain ruthenium oxide; mixing ruthenium oxide, hexadecyl trimethyl ammonium bromide and ethylene glycol, and performing ultrasonic dispersion to obtain a ruthenium oxide solution; and mixing the ruthenium oxide solution, H2IrCl6 and potassium hydroxide, adjusting the pH value of the system to be alkaline, then carrying out second heating until reflux and constant-temperature reaction, carrying out solid-liquid separation on the reaction product, and washing to obtain the iridium-ruthenium oxide composite catalyst. The iridium-ruthenium oxide composite catalyst provided by the invention has high activity, high stability and high water electrolysis efficiency.

Description

TECHNICAL FIELD

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

[0002] In the proton exchange membrane water electrolysis (PEMWE) technology, the oxygen evolution reaction (OER) is a key half-reaction, and the kinetic process thereof is slow, so that a high-efficiency catalyst is needed to reduce the overpotential and improve the electrolysis efficiency. At present, iridium-based catalysts are the mainstream anode oxygen evolution catalysts in the field, but the iridium element is extremely low in abundance, and it is difficult to meet the needs of future commercial large-scale applications. Ruthenium-based catalysts have great application potential in PEMWE due to their high intrinsic activity. However, oxidation and dissolution easily occur in the reaction process, resulting in rapid deactivation, which is a major challenge to the commercial application thereof.

[0003] Therefore, it is of great significance to develop a ruthenium-based catalyst with high activity and high stability for promoting the large-scale development of PEMWE technology. SUMMARY

[0004] The application aims to provide an iridium-ruthenium oxide composite catalyst, a preparation method thereof and a proton exchange membrane water electrolysis device to solve the above problems.

[0005] To achieve the above object, the following technical solutions are adopted in the application: A preparation method of an iridium-ruthenium oxide composite catalyst, comprising: Sodium nitrate, ruthenium chloride and water are mixed to prepare a mixed solution, and then the mixed solution is dried and ground to obtain a mixture; The mixture is placed on the surface of a nickel foil, and a joule heating device is used for first heating, and then cooling to obtain ruthenium oxide; The ruthenium oxide, cetyltrimethylammonium bromide and ethylene glycol are mixed to obtain a ruthenium oxide solution by ultrasonic dispersion; the ruthenium oxide solution, H2IrCl6 and potassium hydroxide are mixed to obtain an alkaline mixture, and then the alkaline mixture is subjected to second heating to reflux and constant temperature reaction, and the reaction product is separated into solid and liquid and then washed to obtain the iridium-ruthenium oxide composite catalyst.

[0006] The sodium nitrate is heated into a molten salt state, and is used as an oxidizing agent to oxidize the ruthenium chloride into ruthenium oxide, and the reaction equation is as follows: RuCl3+ 3NaNO3 high temperature = RuO2+ 3NaCl + 3NO2↑ + 1 / 2O2↑.

[0007] This is an Adams molten salt method, which has fast synthesis efficiency and high synthesis purity.

[0008] The dispersant hexadecyl trimethyl ammonium bromide mainly plays a role of dispersion, improves the dispersion of ruthenium oxide in ethylene glycol, and avoids excessive aggregation of the ruthenium oxide to affect the dispersion effect of the attachment of the iridium nanoclusters.

[0009] The ethylene glycol mainly plays a role of reduction of the iridium chloride acid into iridium single element as a solvent and a reducing agent, and the slow reduction effect of the ethylene glycol as a weak reducing agent is beneficial to the dispersion of the iridium on the surface of the ruthenium oxide and reduces the aggregation degree of the iridium nanoparticles.

[0010] The surface of the ruthenium oxide is positively charged, and the electrostatic adsorption principle can be used to adsorb the negative IrCl6 4- , so that the IrCl6 is firmly attached to the surface of the ruthenium oxide and is more uniformly dispersed in the subsequent reduction step.

[0011] Preferably, the mass ratio of the sodium nitrate to the ruthenium chloride is (20-50): 1.

[0012] Preferably, the drying temperature is 60-80℃; and / or, The current of the joule heating device is 55-60A, and the heating time is 20s.

[0013] Preferably, the temperature of the first heating is 300-500℃; and / or, The rate of the heating is 14-24K / s; and / or, The rate of the cooling is 4.6-8K / s.

[0014] The high-temperature thermal shock technology of rapid heating and cooling uses a non-equilibrium high-temperature environment to induce the overflow of oxygen atoms to form oxygen vacancies, and obtains the nanometer ruthenium oxide with a super-fine particle size through a mechanism of limiting the grain growth time and thermal stress fragmentation.

[0015] Preferably, the particle size of the ruthenium oxide is 2.5-5.5nm.

[0016] Preferably, the molar ratio of the ruthenium oxide, the hexadecyl trimethyl ammonium bromide, the H2IrCl6 and the potassium hydroxide is 10:10-100:2-5:2.

[0017] Preferably, the pH of the alkaline mixture is 8-12.

[0018] Preferably, the temperature of the constant-temperature reaction is 130-150℃.

[0019] The application also provides an iridium-ruthenium oxide composite catalyst prepared by using the preparation method of the iridium-ruthenium oxide composite catalyst.

[0020] The application also provides a proton exchange membrane water electrolysis device comprising the iridium-ruthenium oxide composite catalyst.

[0021] Compared with the prior art, the application has the following beneficial effects: The preparation method of the iridium-ruthenium oxide composite catalyst provided by the application adopts the Adams molten salt method, uses a Joule heating device, and uses a high-temperature thermal shock technology to prepare ruthenium oxide with rich oxygen vacancies and ultra-fine particle size through rapid heating and cooling. Compared with commercial ruthenium oxide and ruthenium oxide synthesized by a muffle furnace, the preparation period is short, and the particle size of the obtained ruthenium oxide is small. Iridium clusters are grown on the surface of the obtained ruthenium oxide through a wet chemical method-solvent thermal reduction to form a stable heterojunction. Building a heterostructure is an effective strategy for adjusting the local electronic environment, stabilizing the structure through interface charge transfer, and effectively relieving Ru oxidation and dissolution. The construction of the heterostructure often depends on traditional heat treatment processes. The high-temperature thermal shock technology used in the application can quickly synthesize ultra-fine nanoparticles rich in oxygen vacancies through non-equilibrium thermodynamics, which is simple and efficient.

[0022] The iridium-ruthenium oxide composite catalyst provided by the application belongs to an oxygen vacancy-rich Ir / RuO2 ultra-fine nanoparticle catalyst, has excellent OER performance, and has an overpotential of only 150 mV at a current density of 10 mA / cm 2 , can be stably operated for more than 500 hours, and has a voltage attenuation rate of only 77 µV / h.

[0023] The proton exchange membrane water electrolysis device provided by the application has excellent performance, can achieve an industrial-grade current density of 1 A / cm 2 at a battery voltage of 1.6 V, and can be stably operated for more than 100 h at a current density of 1 A / cm 2 , thereby significantly improving the water electrolysis efficiency.

[0024] The application effectively relieves the oxidation and dissolution of the ruthenium-based catalyst through a unique catalyst design and mechanism, improves the catalytic activity, provides an effective way to improve the performance of the ruthenium-based catalyst, and helps to promote the commercialization process of the proton exchange membrane water electrolysis technology. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation on the scope of the application.

[0026] Figure 1 HTS curve for the synthesis of the ruthenium oxide of Example 1; Figure 2 Linear sweep voltammetry curve of different ruthenium oxides; Figure 3 Electron paramagnetic resonance spectra of different ruthenium oxides; Figure 4 TEM images of different ruthenium oxides; Figure 5 Particle size distribution of different ruthenium oxides; Figure 6 Linear sweep voltammograms of RuO2 obtained in Example 1 and iridium-ruthenium oxide composite catalysts obtained in Example 1, Example 6 to Example 8; Figure 7 Linear sweep voltammograms of RuO2 obtained in Example 1 and iridium-ruthenium oxide composite catalysts obtained in Example 1, Example 9; Figure 8 TEM images and particle size distribution of iridium-ruthenium oxide composite catalyst obtained in Example 1 at different magnifications; Figure 9 Chronoamperometric test curves of ruthenium oxide and iridium-ruthenium oxide composite catalyst obtained in Example 1; Figure 10 Linear sweep voltammograms of RuO2 obtained in Example 1, Comparative Example 1 and Comparative Example 2, iridium-ruthenium oxide composite catalyst obtained in Example 1 and Comparative Example 2, and iridium provided in Comparative Example 3; Figure 11 Linear sweep voltammograms of ruthenium oxide obtained in Example 1 and iridium-ruthenium oxide composite catalysts obtained in Comparative Example 4 to Comparative Example 6; Figure 12 PEM WE polarization curves obtained in deionized water at 60°C with ruthenium oxide obtained in Example 1, iridium-ruthenium oxide composite catalyst, ruthenium oxide provided in Comparative Example 1 and iridium oxide provided in Comparative Example 7 as anode catalyst, and commercial Pt / C as cathode catalyst; Figure 13 Constant current chronoamperometric curves obtained in deionized water at 60°C at 1 A / cm2with ruthenium oxide obtained in Example 1, iridium-ruthenium oxide composite catalyst as anode catalyst, and commercial Pt / C as cathode catalyst. 2 DETAILED DESCRIPTION

[0027] The embodiments of the present application will be described in detail below with specific examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be regarded as limiting the scope of the present application. The specific conditions are not specified in the examples, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be purchased on the market.

[0028] Example 1 ​The embodiment provides an iridium-ruthenium oxide composite catalyst, and a preparation method thereof. First step: preparation of oxygen vacancy-rich ultrafine ruthenium oxide nanoparticles 5g NaNO3 and 100 mg RuCl3•xH2O are mixed and dispersed in 30 mL deionized water, and dried in an 80℃ oil bath overnight. Then the dried mixture is ground for 1 hour, and 1g of the mixture is uniformly spread on the surface of a 0.2cm-thick nickel foil, which is connected to two electrodes of a direct current power supply of a joule heating device, and heated at a current of 60 A for 20s (temperature 350℃), at a heating rate of 16.5K / s and a cooling rate of 3.9K / s, to obtain ruthenium oxide with rich oxygen vacancies and ultrafine particle size (denoted as RuO2-HTS 300℃). The HTS curve of the synthesized ruthenium oxide is shown in 2 The nickel foil surface, thickness of 0.2cm, connected to two electrodes of a direct current power supply of a joule heating device, heated at a current of 60 A for 20s (temperature 350℃), at a heating rate of 16.5K / s and a cooling rate of 3.9K / s, to obtain ruthenium oxide with rich oxygen vacancies and ultrafine particle size (denoted as RuO2-HTS 300℃). The HTS curve of the synthesized ruthenium oxide is shown in Figure 1 .

[0029] Second step: growth of iridium clusters on the surface of ruthenium oxide 10mg RuO2 is mixed with 0.1g cetyltrimethylammonium bromide (CTAB) as a seed crystal and dispersed in 30mL ethylene glycol, and ultrasonic treatment is performed for 2 hours to obtain a uniformly dispersed ruthenium oxide solution. 2.5mL 0.01M Ir 4+ (H2IrCl6) is added to the above solution, 1M KOH is added, and the pH value of the solution is adjusted to 8. The above mixed solution is placed in an oil bath, heated and stirred through a reflux device, and kept at a constant temperature for 1 hour, and the reaction temperature is 150℃; after the reaction, solid-liquid separation is performed, and the solid is washed with acetone, ethanol and ionized water three times in sequence to obtain Ir / RuO2, that is, an iridium-ruthenium oxide composite catalyst.

[0030] Example 2 Different from example 1, the heating current of the joule device is 58 A, the time is 20s, and the temperature is 300℃.

[0031] Example 3 Different from example 1, the heating current of the joule device is 62 A, the time is 20s, and the temperature is 400℃.

[0032] Example 4 Different from example 1, the heating current of the joule device is 65 A, the time is 20s, and the temperature is 450℃.

[0033] Example 5 Different from example 1, the heating current of the joule device is 67 A, the time is 20s, and the temperature is 500℃.

[0034] Example 6 Different from example 1, in the second step, the pH value of the solution is adjusted to 9.

[0035] Example 7 Different from example 1, in the second step, the pH value of the solution was adjusted to 10.

[0036] Example 8 Different from example 1, in the second step, the pH value of the solution was adjusted to 12.

[0037] Example 9 Different from example 1, in the second step, the reaction temperature was 130℃.

[0038] Comparative example 1 Commercial ruthenium oxide (purchased from Macklin, recorded as Com RuO2) was used as a reference.

[0039] Comparative example 2 Different from example 1, the mixture after drying was ground for 1 hour, and the mixture was treated in a muffle furnace at 350℃, the heating rate was 10℃ / min, and the holding time was 30 min, to obtain ruthenium oxide (recorded as RuO2-MFC).

[0040] The linear sweep voltammetry curves of the ruthenium oxide obtained in examples 1 to 5, comparative example 1 and comparative example 2 were obtained under different synthesis temperatures and methods, as shown in FIG. 1. Figure 2 The linear sweep voltammetry curves were tested by Chenhua 760 electrochemical workstation, the test voltage range was 0.6 V-1.2 V, and the scan rate was 5 mV / s. First, the catalyst slurry was prepared, before preparing the working electrode, 2 mg of Ir / RuO2-HTS catalyst was weighed, 450 uL of anhydrous ethanol, 50 uL of ultrapure water, and 20 uL of 5% Nafion solution were added in turn, and the ink solution was obtained by ultrasonic dispersion for 2 hours. A certain amount of catalyst ink (different catalysts maintained the same noble metal loading, 0.3 mg / cm 2 ) was dropped on the polished working electrode (GC glassy carbon electrode, diameter 5 mm, area 0.196 cm 2 ), and naturally air-dried for standby. The area specific activity and mass specific activity were normalized according to the obtained current, taking into account the GCE and noble metal loading area. All electrochemical experiments were tested in a standard three-electrode half-cell system at room temperature, the glassy carbon electrode with catalyst droplets as the working electrode, 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 corrected in advance, and converted to the reversible hydrogen electrode potential (vs RHE), and the conversion formula 1 was: E (vs. RHE) = E (vs. SCE) + 0.652 V + 0.0591 * pH V (1) Wherein, ESCE is the voltage value obtained in the test, and 0.652V is the zero current potential value obtained after the SCE electrode is calibrated with the standard hydrogen electrode before the test.

[0041] From Figure 1 It can be seen that the HTS temperature range is 300-500℃, the optimal HTS temperature is 350℃, and the oxidation ruthenium at 10mA / cm 2 The overpotential is 167mV, which is better than the muffle furnace sample and the commercial ruthenium oxide sample.

[0042] It should be noted that in the actual heating process, under the condition that the same conditions are kept, the sample heated at 300℃ in Example 2 is not completely heated, and the sodium nitrate oxidant is not completely melted, although it has good performance, but the stability is poor. Through comparison of multiple aspects (heating condition, activity and stability), the optimal temperature is selected as 350℃.

[0043] The ruthenium oxide obtained by testing Example 1, Comparative Example 1 and Comparative Example 2 is obtained. The electron paramagnetic resonance spectrum is shown in Figure 3 (Black curve and purple curve overlap).

[0044] It can be seen from Figure 3 that the oxygen vacancy concentrations of ruthenium oxides prepared by different synthesis methods are different. The EPR test found that the HTS-synthesized ruthenium oxide has the highest oxygen vacancy concentration, indicating that the HTS synthesis method can introduce more oxygen vacancies, which is beneficial to the charge transfer in the OER process.

[0045] The ruthenium oxide obtained by testing Example 1, Comparative Example 1 and Comparative Example 2 is obtained. The TEM diagram is shown in Figure 4 , and the particle size distribution diagram is shown in Figure 5 .

[0046] The commercial ruthenium oxide particles are large, and the ruthenium oxides synthesized by the muffle furnace and the HTS are relatively small in size and uniformly dispersed. The average particle size of the commercial ruthenium oxide is 18.4 nm, the average particle size of the ruthenium oxide synthesized by the muffle furnace is 4.4 nm, and the average particle size of the ruthenium oxide synthesized by the HTS is 3.5 nm. It shows that the HTS synthesis method is beneficial to the synthesis of ultrafine particles, and avoids excessive agglomeration and secondary growth of particles.

[0047] The linear sweep voltammetry curves of the RuO2 obtained by testing Example 1 and the iridium-ruthenium oxide composite catalysts obtained by Example 1, Example 6 to Example 8 are shown in Figure 6 .

[0048] It can be seen from Figure 6 that the optimal synthesis pH is 8, and the catalytic activity of Ir / RuO2 is improved compared with the activity of ruthenium oxide alone.

[0049] The linear sweep voltammetric curves of RuO2 obtained in Example 1 and the iridium-ruthenium oxide composite catalysts obtained in Example 1 and Example 9 are as follows: Figure 7 shown.

[0050] 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.

[0051] The iridium-ruthenium oxide composite catalyst obtained in Example 1 was tested to obtain TEM images and particle size distribution diagrams at different magnifications, as shown in FIG. Figure 8 As shown, a is 200 kX, b is 500 kX, c is 2Mx, and d is the particle size distribution diagram.

[0052] from Figure 8 It can be seen that 1.02 nm Ir nanoclusters are evenly distributed on the ruthenium oxide surface, indicating the formation of a robust heterogeneous interface.

[0053] The ruthenium oxide and iridium-ruthenium oxide composite catalyst obtained in Example 1 were 2 The chronopotentiometry test was performed at the current density, and the results were as follows: Figure 9 shown.

[0054] In 0.5 M H2SO4 electrolyte, Ir / RuO2 catalyst has a 2 It can operate stably for more than 500 hours at the current density with a voltage decay rate of only 77 µV / h, while the ruthenium oxide sample alone completely fails after running for 30 hours, indicating that the iridium loading helps to inhibit the oxidative dissolution of Ru.

[0055] Comparative Example 3 Different from Example 1, ruthenium oxide was not added, and Ir (Ir NPs) was synthesized alone.

[0056] The linear sweep voltammetry 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 as follows: Figure 10 shown.

[0057] Compared with iridium alone, ruthenium oxide alone synthesized by muffle furnace and HTS, commercial ruthenium oxide and Ir / RuO2-MFC samples, ruthenium oxide synthesized by HTS and then loaded with Ir (Ir / RuO2-HTS) has the best catalytic activity, with an overpotential of only 150 mV at a current density of 10 mA / cm2.

[0058] Comparative Example 4 The synthesis of iridium oxide-ruthenium oxide composite catalyst was attempted. The ruthenium oxide synthesized by HTS was added to the basic precipitation of chloroiridic acid, and then pyrolysis at 500°C to form iridium oxide.

[0059] Comparative Example 5 The difference from Comparative Example 4 is that the pyrolysis temperature is 550°C.

[0060] Comparative Example 6 The difference from Comparative Example 4 is that the pyrolysis temperature is 600°C.

[0061] The linear sweep voltammetry curves of the iridium-ruthenium oxide composite catalyst obtained in Example 1, the iridium oxide-ruthenium oxide composite catalysts obtained in Comparative Examples 4 to 6 in 0.5 M H2SO4 electrolyte are shown in Figure 11 .

[0062] The catalytic activity of iridium oxide-ruthenium oxide catalysts at different pyrolysis temperatures was investigated. It was found that compared with the iridium-ruthenium oxide composite catalyst, the catalytic activity of the iridium oxide-ruthenium oxide catalysts all decreased, which may be due to the secondary heat treatment leading to the thermal growth of ruthenium oxide again, resulting in further decrease of catalytic activity.

[0063] Comparative Example 7 Commercial iridium oxide was used as a reference, denoted as Com IrO2.

[0064] The PEM WE polarization curves obtained in deionized water at 60°C using the ruthenium oxide obtained in Example 1, the iridium-ruthenium oxide composite catalyst, 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 catalyst are shown in Figure 12 . The noble metal loading of the anode is 1 mg Ru+Ir / cm 2 , and the cathode is 0.36 mg Pt / cm 2 . The battery voltage was not IR compensated.

[0065] Compared with commercial ruthenium oxide, commercial iridium oxide and HTS-synthesized single ruthenium oxide, the Ir / RuO2 sample showed the best catalytic activity, reaching a current density of 1 A / cm 2 at 60°C, only requiring a battery voltage of 1.6 V.

[0066] The constant current chronopotentiometric curves obtained in deionized water at 60°C at a current density of 1 A / cm 2 using the ruthenium oxide obtained in Example 1, the iridium-ruthenium oxide composite catalyst as anode catalyst and commercial Pt / C as cathode catalyst are shown in Figure 13 . The noble metal loading of the anode is 1 mg Ru+Ir / cm 2 , and the cathode is 0.36 mg Pt / cm 2.

[0067] 1 A / cm 2 The Ir / RuO2 catalyst can be stably operated for 100 h at a current density of 1 A / cm2, while the single ruthenium oxide is completely disabled after operating for several hours.

[0068] Comparative Example 8 Different from Example 1, the CTAB is replaced by polyvinylpyrrolidone (PVP), and the activity of the finally synthesized catalyst is not as good as that of CTAB. PVP is not suitable for the dispersion of ruthenium oxide.

[0069] Comparative Example 9 Different from Example 1, the ethylene glycol is replaced by sodium borohydride.

[0070] As a strong reducing agent, the reduction speed of sodium borohydride is too fast, which leads to the agglomeration of iridium nanoparticles and the phase separation of ruthenium oxide, and thus a good heterojunction cannot be formed.

[0071] Comparative Example 10 Different from Example 1, the H2IrCl6 is replaced by other iridium sources such as IrCl3 and Ir(acac)3, and the activity of the catalyst after loading decreases, which is presumably due to the phase separation.

[0072] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for producing an iridium-ruthenium oxide composite catalyst, characterized by, The application relates to a preparation method of an iridium-ruthenium oxide composite catalyst. Sodium nitrate, ruthenium chloride and water are mixed to prepare a mixed solution, which is dried and ground to obtain a mixture; The mixture is placed on the surface of a nickel foil, and first heating is performed by using a joule heating device, and then cooling is performed to obtain ruthenium oxide; The ruthenium oxide, cetyltrimethylammonium bromide and ethylene glycol are mixed and ultrasonically dispersed to obtain a ruthenium oxide solution; the ruthenium oxide solution, H2IrCl6 and potassium hydroxide are mixed to obtain an alkaline mixture, and then second heating is performed to reflux and constant-temperature reaction is performed; after solid-liquid separation of a reaction product, washing is performed to obtain the iridium-ruthenium oxide composite catalyst.

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

1.

3. The method for preparing an iridium-ruthenium oxide composite catalyst according to claim 1, characterized by, The drying temperature is 60-80 DEG C. And / or, The current of the joule heating device is 55-60 A, and the heating time is 20 s.

4. The method for preparing an iridium-ruthenium oxide composite catalyst according to claim 1, characterized by, The first heating temperature is 300-500 DEG C. And / or, The heating rate is 14-24 K / s. And / or, The cooling rate is 4.6-8 K / s.

5. The method for preparing an iridium-ruthenium oxide composite catalyst according to claim 1, characterized by, The particle size of the ruthenium oxide is 2.5-5.5 nm.

6. The method for preparing an iridium-ruthenium oxide composite catalyst according to claim 1, characterized by, The mass ratio of the ruthenium oxide, the cetyltrimethylammonium bromide, the H2IrCl6 and the potassium hydroxide is 10:10-100:2-5:

2.

7. The method for preparing an iridium-ruthenium oxide composite catalyst according to claim 1, wherein The pH of the alkaline mixture is 8-12.

8. The method for preparing the iridium-ruthenium oxide composite catalyst according to any one of claims 1 to 7, characterized by, The constant-temperature reaction temperature is 130-150 DEG C.

9. An iridium-ruthenium oxide composite catalyst characterized by, The iridium-ruthenium oxide composite catalyst is prepared by using the preparation method of any one of claims 1-8.

10. A proton exchange membrane device for electrolysis of water, characterized by, The application further relates to an iridium-ruthenium oxide composite catalyst. The application further relates to an iridium-ruthenium oxide composite catalyst.

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