Ruthenium monatomic doped metastable iridium oxide catalyst, method for preparing and use thereof
Patent Information
- Application Number
- CN202310600299.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-05-25
- Publication Date
- 2026-09-15
- Estimated Expiration
- 2043-05-25
AI Technical Summary
然而，高价态IrO3在酸性环境中容易溶解，导致活性急剧下降
[0021] 1. This invention combines high-temperature solid-state sintering and lithium-ion/hydrogen-ion substitution to prepare a metastable iridium oxide catalyst doped with ruthenium single atoms. By doping ruthenium atoms to construct a local Ru-O-Ir structure, the valence state of some Ir is moderately reduced, avoiding excessive oxidation (i.e., formation of Ir) during the reconstruction process. >+4 This invention significantly improves the stability of the catalyst in acidic media while maintaining its intrinsic activity, achieving high activity and stability in acidic oxygen evolution reaction (PEMWE). The invention solves the trade-off between high activity and stability of the catalyst at the atomic level, and has important guiding significance for the development of efficient oxygen evolution catalysts for PEMWE applications.
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Figure CN116695140B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of nanocatalyst technology, specifically relating to ruthenium single-atom doped metastable iridium oxide catalysts, their preparation methods, and applications. Background Technology
[0002] Electrolysis of water for hydrogen production, currently the lowest carbon-emission hydrogen source among various options, is poised for rapid development. Acid proton exchange membrane (PEM) water electrolysis technology boasts advantages such as high current density, high energy efficiency, high hydrogen purity, and fast response speed, making it a key technology for future green hydrogen production. However, the PEM anode region is a strongly acidic environment, where most anolyte oxygen evolution catalysts are easily corroded and dissolved, exhibiting poor stability. To date, iridium-based oxides (IrO2) have been used... x IrO₂ is the only known oxygen evolution catalyst used on a large industrial scale in PEM. However, current IrO₂... x The catalysts still suffer from high cost and poor durability, making it difficult to meet the requirements of high performance and long-term stability at commercial current densities. Therefore, designing and preparing highly active and durable water electrolysis catalysts is key to the widespread application of this technology.
[0003] Recent studies have shown that metastable iridium oxide exhibits extremely high activity in the acidic oxygen evolution reaction (OER). It possesses a layered protonated structure distinct from the rutile phase, readily undergoing deprotonation and reconstruction in highly oxidizing environments to form a highly active high-valence IrO3 intermediate. However, the high-valence IrO3 readily dissolves in acidic environments, leading to a sharp decline in activity. Therefore, improving the stability of metastable iridium oxide catalysts in acidic media without reducing their intrinsic activity is of significant guiding importance for developing highly efficient OER catalysts for proton exchange membrane electrolysis (PEMWE) applications. Summary of the Invention
[0004] To address the trade-off between high activity and stability in existing metastable iridium oxide catalysts, this invention provides a ruthenium single-atom-doped metastable iridium oxide catalyst, its preparation method, and its applications. This catalyst can maintain long-term stability in acidic oxygen evolution reactions and can be mass-produced.
[0005] The technical solution adopted in this invention is as follows:
[0006] The metastable iridium oxide catalyst doped with ruthenium single atoms has a bulk morphology with a layered proton (hydrogen ion) structure and a trigonal crystal structure; wherein, ruthenium atoms are doped by replacing 0.5% to 3% of iridium atoms.
[0007] A method for preparing a ruthenium single-atom-doped metastable iridium oxide catalyst includes the following steps:
[0008] Step 1: In order to ensure that ruthenium single atoms can be completely doped, lithium carbonate, iridium powder and ruthenium powder in a mass ratio of 172:300:(2~12) are mixed and ground to obtain mixed powder A;
[0009] Step 2: Sinter the mixed powder A in air at 900-1000 degrees Celsius for 20-24 hours, and then allow it to cool naturally to obtain the precursor product B, specifically ruthenium-containing lithium intercalated iridium oxide.
[0010] Step 3: Pour the precursor product B into dilute sulfuric acid to obtain a mixture C. After stirring and reacting, the mixture is centrifuged and ultrasonically washed to obtain product D. Then, the product D is vacuum dried and ground to obtain the ruthenium single-atom doped metastable iridium oxide catalyst.
[0011] Furthermore, the grinding time in step 1 is 20 to 30 minutes.
[0012] Furthermore, the heating rate in step 2 during the sintering process is 1–5 degrees Celsius per minute.
[0013] Furthermore, in step 3, the concentration of dilute sulfuric acid is 0.5 to 1 mol per liter, and the concentration of precursor product B in mixture C does not exceed 5 mg per milliliter.
[0014] Furthermore, the temperature required for stirring in step 3 is 25–30 degrees Celsius, the stirring time is 5–8 hours, and the stirring speed is 600–800 revolutions per minute.
[0015] Further, the specific process of centrifugation and ultrasonic washing in step 3 is as follows: after the mixture C is stirred and reacted, a mixture E is obtained; the mixture E is first centrifuged, the product is collected and ultrasonically washed with deionized water or a polar solvent; then centrifugation is continued, the product is collected and ultrasonically washed with deionized water or a polar solvent; the process of centrifugation and ultrasonic washing is repeated 3 to 5 times to obtain product D.
[0016] Furthermore, the centrifugation speed is 7000-8000 rpm for each centrifugation, the centrifugation time is 5-8 minutes for each centrifugation, and the ultrasonic washing time is 5-10 minutes for each ultrasonic washing.
[0017] Furthermore, the polar solvent includes, but is not limited to, anhydrous ethanol and isopropanol.
[0018] Furthermore, in step 3, the vacuum drying temperature is 50–80 degrees Celsius, and the drying time is 10–24 hours.
[0019] The present invention also provides the application of the ruthenium single-atom doped metastable iridium oxide catalyst described in any of the above technical solutions or the ruthenium single-atom doped metastable iridium oxide catalyst obtained by the preparation method described in any of the above technical solutions in the acidic oxygen evolution reaction of water electrolysis to produce hydrogen.
[0020] The beneficial effects of this invention are as follows:
[0021] 1. This invention combines high-temperature solid-state sintering and lithium-ion / hydrogen-ion substitution to prepare a metastable iridium oxide catalyst doped with ruthenium single atoms. By doping ruthenium atoms to construct a local Ru-O-Ir structure, the valence state of some Ir is moderately reduced, avoiding excessive oxidation (i.e., formation of Ir) during the reconstruction process. >+4 This invention significantly improves the stability of the catalyst in acidic media while maintaining its intrinsic activity, achieving high activity and stability in acidic oxygen evolution reaction (PEMWE). The invention solves the trade-off between high activity and stability of the catalyst at the atomic level, and has important guiding significance for the development of efficient oxygen evolution catalysts for PEMWE applications.
[0022] 2. This invention obtains a protonated intercalated iridium oxide through a lithium-ion / hydrogen-ion substitution process. The intercalated protons are enriched between the lattice layers and connected to the vertex oxygen atoms in the lattice through hydrogen bonding. Under reaction conditions, the protonated structure can provide abundant protons to the catalyst surface through the rapid migration of bulk protons, which helps to neutralize the Ir sites on the surface that tend to oxidize due to deprotonation, thereby inhibiting excessive oxidation and dissolution during the reaction process, ensuring the stability of the structure to a certain extent, and delaying the degradation process of the catalyst.
[0023] 3. The preparation method of this invention is simple and easy to control the doping amount of ruthenium atoms to achieve the most ideal doping concentration. The prepared ruthenium single-atom doped metastable iridium oxide catalyst, when applied to a three-electrode system, achieves an overpotential of only 247 mV at a current density of 10 mA and maintains stable oxygen evolution for more than 1100 hours. When applied to a proton exchange membrane electrolyzer, it achieves stable hydrogen production at a current density of 1 A for more than 250 hours at 80 degrees Celsius. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 This is a scanning electron microscope image of the ruthenium single-atom-doped metastable iridium oxide catalyst obtained in Example 1 of the present invention;
[0026] Figure 2 The X-ray diffraction pattern of the ruthenium single-atom-doped metastable iridium oxide catalyst obtained in Example 1 of this invention;
[0027] Figure 3 The extended edge X-ray absorption fine structure of ruthenium in the metastable iridium oxide catalyst doped with ruthenium single atom obtained in Example 1 of the present invention;
[0028] Figure 4 The polarization curve of the ruthenium single-atom-doped metastable iridium oxide catalyst (M-IrO2-1%Ru) obtained in Example 1 as described in Example 2 of this invention under acidic oxygen evolution reaction;
[0029] Figure 5 The potential change curve of the ruthenium single-atom doped metastable iridium oxide catalyst obtained in Example 1 as described in Example 2 of the present invention over time at a current density of 10 mA per square centimeter;
[0030] Figure 6 The potential change curve of the ruthenium single-atom doped metastable iridium oxide catalyst obtained in Example 1 of the present invention at a current density of 1 ampere per square centimeter in a proton exchange membrane electrolyzer at 80 degrees Celsius, as described in Example 3 of the present invention.
[0031] Figure 7 The polarization curves of the pure metastable iridium oxide catalyst (M-IrO2) obtained in the comparative example under acidic oxygen evolution reaction are shown.
[0032] Figure 8 The potential change curves of the pure metastable iridium oxide catalyst (M-IrO2) obtained in the comparative example and the ruthenium single-atom doped metastable iridium oxide catalyst (M-IrO2-1%Ru) obtained in Example 1 are compared with those of the catalyst over time at a current density of 10 mA per square centimeter.
[0033] Figure 9 The polarization curves of the ruthenium single-atom doped metastable iridium oxide catalysts obtained in Examples 1 (M-IrO2-1%Ru), 4 (M-IrO2-0.5%Ru), and 5 (M-IrO2-3%Ru) of the present invention are compared with those of the pure metastable iridium oxide catalyst (M-IrO2) obtained in the comparative example under acidic oxygen evolution reaction, after normalization by electrochemical area. Detailed Implementation
[0034] To further understand the present invention, preferred embodiments are described below with reference to examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims. All raw materials used in the present invention are not particularly limited in their source; they can be purchased commercially or prepared using conventional methods well known to those skilled in the art.
[0035] The present invention will be further described in detail below with reference to the embodiments.
[0036] Example 1
[0037] This embodiment provides a method for preparing a metastable iridium oxide catalyst doped with a ruthenium single atom, comprising the following steps:
[0038] Step 1: Place 0.43 g of lithium carbonate, 0.75 g of iridium powder and 10 mg of ruthenium powder in a mortar and mix well. Grind for 20 minutes to obtain mixed powder A.
[0039] Step 2: Place the mixed powder A in a quartz crucible and sinter it at high temperature in an air atmosphere. The sintering temperature is 950 degrees Celsius, the holding time is 24 hours, and the heating rate is 1 degree Celsius per minute. After sintering, allow it to cool naturally. The resulting product is ground to obtain precursor product B, specifically ruthenium-containing lithium intercalated iridium oxide.
[0040] Step 3: Take 100 mg of the above precursor product B and disperse it in 20 mL of dilute sulfuric acid with a concentration of 0.5 mol / L. Stir the mixture at 25 degrees Celsius for 5 hours at a stirring speed of 600 rpm to obtain a mixture E. Centrifuge the mixture E, collect the product and wash it with deionized water using ultrasound. Then continue centrifugation, collect the product and wash it with anhydrous ethanol using ultrasound. Repeat the centrifugation and ultrasound washing process 3 times to obtain product D. Place product D in a vacuum drying oven at 50 degrees Celsius and dry it for 10 hours. After grinding, obtain a ruthenium single-atom doped metastable iridium oxide catalyst, denoted as M-IrO2-1%Ru.
[0041] The centrifugation speed was 8000 rpm for each centrifugation, the centrifugation time was 5 minutes for each centrifugation, and the ultrasonic washing time was 5 minutes for each ultrasonic washing.
[0042] According to inductively coupled plasma optical emission spectrometry (ICP-OES), the proportion of ruthenium atoms in the metastable iridium oxide catalyst doped with ruthenium single atoms obtained in this embodiment is 1%.
[0043] Depend on Figure 1 The scanning electron microscope image shown shows that the morphology of the ruthenium single-atom doped metastable iridium oxide catalyst obtained in this embodiment is a layered stacked bulk (as shown by the crack), and the bulk size is 500-1500 nanometers.
[0044] Depend on Figure 2 The X-ray diffraction pattern shown indicates that the ruthenium single-atom-doped metastable iridium oxide catalyst obtained in this embodiment belongs to the R-3m(166) crystal group. The crystal structure is trigonal, and the layers (ABC layers) are connected by protons.
[0045] Figure 3The extended edge X-ray absorption fine structure of ruthenium in the metastable iridium oxide catalyst doped with ruthenium single atoms obtained in this embodiment is shown in the image at an atomic distance of [missing information]. The presence of a Ru-O bond signal peak at the point indicates the absence of Ru-O-Ru bond formation, suggesting that Ru doping in the Ir-O lattice is in the form of single-atom dispersion and forms a localized Ir-O-Ru coordination configuration.
[0046] Example 2
[0047] This embodiment tests the oxygen evolution performance of the ruthenium single-atom doped metastable iridium oxide catalyst obtained in Example 1 in an H-type electrolyzer.
[0048] In an H-type electrolytic cell, carbon paper loaded with the ruthenium single-atom-doped metastable iridium oxide catalyst obtained in Example 1 was used as the anode, and a silver / silver chloride electrode in a saturated potassium chloride solution was used as the reference electrode. The cathode reaction was the hydrogen evolution reaction of the carbon rod. The anode was prepared as follows: 5 mg of ruthenium single-atom-doped metastable iridium oxide catalyst was dissolved in a mixture of 750 μL of isopropanol, 250 μL of deionized water and 20 μL of perfluorosulfonic acid 117 dispersion (Nafion), sonicated in an ice bath for 30 minutes, and the resulting catalyst solution was uniformly sprayed onto the surface of a carbon paper with an area of 4 square centimeters using a spray gun.
[0049] Using 0.5 mol / L dilute sulfuric acid as the electrolyte, a 1 cm² piece of carbon paper loaded with a metastable iridium oxide catalyst doped with ruthenium single atoms was immersed in the electrolyte for polarization performance testing. The test results are as follows: Figure 4 As shown, a current density of 10 mA can be achieved at an overpotential of 247 mV.
[0050] Using 0.5 mol / L dilute sulfuric acid as the electrolyte, a 1 square centimeter area carbon paper loaded with a metastable iridium oxide catalyst doped with ruthenium single atoms was immersed in the electrolyte for stability testing. The test was conducted using a constant current method, and the results are as follows: Figure 5 As shown, it can operate stably for more than 1100 hours at a current density of 10 mA per square centimeter.
[0051] Example 3
[0052] This embodiment tests the water electrolysis performance of the ruthenium single-atom doped metastable iridium oxide catalyst obtained in Example 1 in a PEM electrolyzer.
[0053] The PEM electrolyzer uses a proton exchange membrane 117. The cathode catalyst and the anode catalyst are coated on both sides of the membrane to form a membrane electrode. One side of the membrane electrode is covered with carbon paper as the cathode gas diffusion layer, and the other side is covered with Ti felt as the anode gas diffusion layer. The cathode catalyst is commercial platinum carbon (platinum: 20%), and the anode catalyst is the ruthenium single-atom doped metastable iridium oxide catalyst obtained in Example 1.
[0054] The specific preparation method of the membrane electrode is as follows: 5 mg of ruthenium single-atom-doped metastable iridium oxide catalyst was dissolved in a mixture of 1 mL isopropanol and 50 μL of perfluorosulfonic acid 117 dispersion (Nafion), and ultrasonicated in an ice bath for 30 minutes to form an anode catalyst slurry; 5 mg of commercial platinum-carbon catalyst was dissolved in a mixture of 1 mL isopropanol and 50 μL of perfluorosulfonic acid 117 dispersion (Nafion), and ultrasonicated in an ice bath for 30 minutes to form a cathode catalyst slurry; the cathode catalyst slurry and anode catalyst slurry were uniformly sprayed onto both sides of the proton exchange membrane using a spray gun. The geometric area is 2*2 cm. During the catalyst spraying process, the proton exchange membrane is adsorbed onto the platform through a vacuum heating stage to keep the membrane flat. The temperature of the heating stage is 80 degrees Celsius. The spraying order of the cathode catalyst slurry and the anode catalyst slurry has no substantial impact on the performance characterization of the membrane electrode. After spraying, the membrane electrode loaded with the cathode catalyst and the anode catalyst is hot-pressed through a hot press to improve the adhesion between the catalyst and the membrane. The hot-pressing temperature is 100 degrees Celsius, the hot press pressure is set to 2 MPa, and the hot-pressing time is 1 minute. After hot pressing, the membrane electrode is assembled with the PEM electrolyzer.
[0055] The assembled PEM electrolyzer was connected to the electrochemical workstation, auxiliary circulating water system, and heating device. Pure water was used as the reactant, with a water circulation rate of 1.5 ml / min and a reaction temperature of 80 degrees Celsius. The test was conducted using a constant current method, and the test results are as follows: Figure 6 As shown, it can operate stably for more than 250 hours at a current density of 1 amp per square centimeter.
[0056] Comparative Example
[0057] This comparative example prepared a pure metastable iridium oxide catalyst without ruthenium single-atom doping. The preparation process was the same as that in Example 1, except that ruthenium powder was not added during the preparation process; the other steps were the same, and it was denoted as M-IrO2.
[0058] The electrochemical testing method described in Example 2 was used: 0.5 mol / L dilute sulfuric acid was used as the electrolyte. A carbon paper sample containing a pure metastable iridium oxide catalyst with an area of 1 square centimeter was immersed in the electrolyte for polarization performance testing. The test results are as follows: Figure 7 As shown, a current density of 10 mA can be achieved at an overpotential of 250 mV, and the catalytic activity is similar to... Figure 4Similar to the ruthenium single-atom doped metastable iridium oxide shown; using dilute sulfuric acid with a concentration of 0.5 mol / L as the electrolyte, a carbon paper sample of pure metastable iridium oxide catalyst with an area of 1 square centimeter was immersed in the electrolyte for stability testing. The test was conducted using a constant current method, and the test results are as follows. Figure 8 As shown, the stability of the ruthenium-doped metastable iridium oxide catalyst at a current density of 10 mA / cm² does not exceed 100 hours, which is far less than the stability of the ruthenium single-atom doped metastable iridium oxide catalyst obtained in Example 1 (1100 hours). This demonstrates that ruthenium single-atom doping significantly improves the stability of the metastable iridium oxide catalyst.
[0059] Example 4
[0060] This embodiment prepared a metastable iridium oxide catalyst doped with ruthenium single atoms. The preparation process was the same as that in Example 1, except that the amount of ruthenium powder added was 5 mg.
[0061] According to inductively coupled plasma optical emission spectrometry (ICP-OES), the proportion of ruthenium atoms in the metastable iridium oxide catalyst doped with ruthenium single atoms obtained in this embodiment is 0.5%, denoted as M-IrO2-0.5%Ru.
[0062] The electrochemical testing method described in Example 2 was used: 0.5 mol / L dilute sulfuric acid was used as the electrolyte. A carbon paper sample containing a pure metastable iridium oxide catalyst with an area of 1 square centimeter was immersed in the electrolyte for polarization performance testing. The test results are as follows: Figure 9 As shown, the catalytic activity is similar to that of M-IrO2-1%Ru. This result indicates that single-atom doping with 0.5% Ru has little effect on the catalytic activity of metastable iridium oxide, and its influence is mainly manifested in stability.
[0063] Example 5
[0064] This embodiment prepared a metastable iridium oxide catalyst doped with ruthenium single atoms. The preparation process was the same as in Example 1, except that the amount of ruthenium powder added was 30 mg.
[0065] According to inductively coupled plasma optical emission spectrometry (ICP-OES), the proportion of ruthenium atoms in the metastable iridium oxide catalyst doped with ruthenium single atoms obtained in this embodiment is 3%, denoted as M-IrO2-3%Ru.
[0066] The electrochemical testing method described in Example 2 was used: 0.5 mol / L dilute sulfuric acid was used as the electrolyte. A carbon paper sample containing a pure metastable iridium oxide catalyst with an area of 1 square centimeter was immersed in the electrolyte for polarization performance testing. The test results are as follows: Figure 9As shown, the catalytic activity is similar to that of M-IrO2-1%Ru. This result indicates that single-atom doping with 3% Ru has little effect on the catalytic activity of metastable iridium oxide, and its influence is mainly manifested in stability.
[0067] Example 6
[0068] This embodiment provides a method for preparing a metastable iridium oxide catalyst doped with a ruthenium single atom, comprising the following steps:
[0069] Step 1: Place 0.43 g of lithium carbonate, 0.75 g of iridium powder and 10 mg of ruthenium powder in a mortar and mix well. Grind for 20 minutes to obtain mixed powder A.
[0070] Step 2: Place the mixed powder A in a quartz crucible and sinter it at high temperature in an air atmosphere. The sintering temperature is 1000 degrees Celsius, the holding time is 20 hours, and the heating rate is 1 degree Celsius per minute. After sintering, allow it to cool naturally. The resulting product is ground to obtain precursor product B, specifically ruthenium-containing lithium intercalated iridium oxide.
[0071] Step 3: Take 100 mg of the above precursor product B and disperse it in 20 mL of dilute sulfuric acid with a concentration of 0.5 mol / L. Stir the mixture at 25 degrees Celsius for 5 hours at a stirring speed of 600 rpm to obtain a mixture E. Centrifuge the mixture E, collect the product and ultrasonically wash it with deionized water. Then continue centrifugation, collect the product and ultrasonically wash it with anhydrous ethanol. Repeat the centrifugation and ultrasonic washing process 3 times to obtain product D. Place product D in a vacuum drying oven at 50 degrees Celsius and dry it for 10 hours. After grinding, obtain a ruthenium single-atom doped metastable iridium oxide catalyst.
[0072] The centrifugation speed was 8000 rpm for each centrifugation, the centrifugation time was 5 minutes for each centrifugation, and the ultrasonic washing time was 5 minutes for each ultrasonic washing.
[0073] The above embodiments are only for illustrating the principles and advantages of the present invention, and are not intended to limit the present invention. They are only for helping to understand the principles of the present invention. The scope of protection of the present invention is not limited to the above configurations and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the disclosed technology without departing from the essence of the present invention, but they are still within the scope of protection of the present invention.
Claims
1. A method for preparing a metastable iridium oxide catalyst doped with a ruthenium single atom, characterized in that, Includes the following steps: Step 1: Take lithium carbonate, iridium powder and ruthenium powder in a mass ratio of 172:300:(2~12), mix and grind them to obtain mixed powder A; Step 2: Sinter the mixed powder A in air at 900-1000 degrees Celsius for 20-24 hours, and then allow it to cool naturally to obtain the precursor product B, specifically ruthenium-containing lithium intercalated iridium oxide. Step 3: Pour the precursor product B into dilute sulfuric acid to obtain a mixture C. After stirring and reacting, the mixture is centrifuged and ultrasonically washed to obtain product D. Then, after vacuum drying and grinding, a metastable iridium oxide catalyst with protonation intercalation obtained through a lithium ion / hydrogen ion substitution process is obtained, namely, a ruthenium single-atom doped metastable iridium oxide catalyst.
2. The method for preparing the ruthenium single-atom doped metastable iridium oxide catalyst according to claim 1, characterized in that, The grinding time in step 1 is 20 to 30 minutes.
3. The method for preparing the ruthenium single-atom doped metastable iridium oxide catalyst according to claim 1, characterized in that, The heating rate in step 2 during the sintering process is 1 to 5 degrees Celsius per minute.
4. The method for preparing the ruthenium single-atom doped metastable iridium oxide catalyst according to claim 1, characterized in that, In step 3, the concentration of dilute sulfuric acid is 0.5 to 1 mol per liter, and the concentration of precursor product B in mixture C does not exceed 5 mg per milliliter.
5. The method for preparing the ruthenium single-atom doped metastable iridium oxide catalyst according to claim 1, characterized in that, The temperature required for stirring in step 3 is 25-30 degrees Celsius, the stirring time is 5-8 hours, and the stirring speed is 600-800 revolutions per minute.
6. The method for preparing the ruthenium single-atom-doped metastable iridium oxide catalyst according to claim 1, characterized in that, The specific process of centrifugation and ultrasonic washing in step 3 is as follows: After the mixture C is stirred and reacted, mixture E is obtained; mixture E is first centrifuged, the product is collected and ultrasonically washed with deionized water or polar solvent; then centrifugation is continued, the product is collected and ultrasonically washed with deionized water or polar solvent; the process of centrifugation and ultrasonic washing is repeated 3 to 5 times to obtain product D.
7. The method for preparing the ruthenium single-atom doped metastable iridium oxide catalyst according to claim 6, characterized in that, The polar solvent is anhydrous ethanol or isopropanol.
8. The method for preparing the ruthenium single-atom doped metastable iridium oxide catalyst according to claim 1, characterized in that, In step 3, the vacuum drying temperature is 50-80 degrees Celsius, and the drying time is 10-24 hours.
9. A ruthenium single-atom-doped metastable iridium oxide catalyst prepared by the method according to any one of claims 1 to 8.