Low-Ir acidic OER electrocatalyst and preparation method and application thereof

Abstract

The invention relates to the field of electrocatalysis, and discloses a low-Ir acidic OER electrocatalyst and a preparation method and application thereof, the electrocatalyst component is MxIryRu1-x-yO2, M is one or more of metal elements of Al, Ga, In, Sn, Sb, Bi and Pb, 0 lt; xlt; 0, 0, 0.3, 0; yt; Yt; and 0.2 part. The electrocatalyst is prepared by the following steps: taking grapes as a template and urea as a gas generator to obtain metal salt loaded three-dimensional foam, and calcining in air to obtain the catalyst. The catalyst shows a porous structure macroscopically and is composed of nano-particles with the particle size of about 5 nm microcosmically, metal M and Ir are evenly distributed into crystal lattices of RuO2, and therefore the electronic structure of RuO2 is optimized. The catalyst shows excellent activity and stability in acidic OER, has lower cell pressure than commercial IrO2 in a proton exchange membrane electrolytic cell, and can stably operate for 1000 h at the current density of 1 A cm <-2 >.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of iridium / ruthenium-based catalyst materials, in particular to a low-Ir acidic OER electrocatalyst and a preparation method and application thereof. BACKGROUND

[0002] Hydrogen is considered as an ideal clean energy carrier to store energy from renewable and intermittent sources, and the stored hydrogen energy can be effectively converted into electrical energy in fuel cells, which is a new type of green energy. Water electrolysis for hydrogen production provides an efficient and environmentally friendly method for large-scale production of high-purity hydrogen. Compared with alkaline water electrolysis technology, acidic water electrolysis using proton exchange membrane as a solid electrolyte has the advantages of higher product purity and higher efficiency. However, few catalysts can operate efficiently and stably under acidic conditions, which greatly hinders the widespread commercialization of acidic water electrolysis. In recent years, researchers have developed new Ru-based catalysts, but they still face the problem of poor stability when applied in acidic water electrolysis, which limits their further application. Therefore, Ir-based materials are still considered to be the most advanced OER electrocatalyst under acidic conditions. However, the current acidic water electrolysis tank anode Ir load is generally greater than 2 mg cm -2 , such a high load makes the cost of acidic electrolysis tank always high, which greatly hinders their large-scale commercial application.

[0003] Oxygen evolution reaction (OER) is not only a key electrochemical process in water electrolysis, but also a core electrochemical reaction in fuel cell technology. However, despite the great potential of these reactions, their implementation is constrained by the slow reaction kinetics, especially in the cathode reaction of fuel cells, inefficient catalysts often lead to a significant reduction in energy conversion efficiency. Therefore, finding efficient, low-cost, and large-scale production of battery electrocatalysts is also a hot topic in current scientific research.

[0004] Therefore, it is very important to rationally design Ir-based catalysts to reduce Ir load while improving their activity and stability, which is not only an important research direction in the field of acidic water electrolysis, but also an important research topic in the field of battery catalysts. SUMMARY

[0005] In view of this, the present application aims to overcome the shortcomings of the current low-Ir-based acidic OER electrocatalyst system, and provides a low-Ir acidic OER electrocatalyst M x Ir y Ru 1-x-yO2. Based on its very high activity and stability in acidic OER, it enables very low cell voltage and long-term operation stability in proton exchange membrane electrolysis hydrogen production, while meeting the application as a battery catalyst, and is expected to replace high Ir load Ru-based noble metal materials to realize large-scale commercial application.

[0006] To achieve the above-mentioned purpose, in a first aspect, the present application provides a low-Ir acidic OER electrocatalyst, which is composed of M x Ir y Ru 1-x-y O2, wherein M is one or more of Al, Ga, In, Sn, Sb, Bi, Pb metal elements, 0

[0007] As a further preferred technical solution of the present application, the content of M in the electrocatalyst component is: 0.1-30 at%, for example 0.1 at%, 0.5 at%, 0.8 at%, 1.0 at%, 5.0 at%, 10.0 at%, 15.0 at%, 20.0 at%, 25.0 at% and the like typical but non-limiting percentage atomic content; the content of Ir is 0.1-20 at%, for example 0.1 at%, 0.5 at%, 0.8 at%, 1.0 at%, 5.0 at%, 10.0 at%, 15.0 at% and the like typical but non-limiting percentage atomic content; the content of Ru is 50-99.8 at%, for example 50 at%, 60 at%, 70 at%, 80 at%, 90 at%, 99.5 at% and the like typical but non-limiting percentage atomic content.

[0008] According to a second aspect of the present application, the present application also provides a preparation method of a low-Ir acidic OER electrocatalyst, which comprises the following steps:

[0009] Step S1, mixing metal salt, glucose and urea to configure a uniform precursor solution, wherein the metal elements contained in the metal salt are M, Ir and Ru, and M is one or more of Al, Ga, In, Sn, Sb, Bi, Pb metal elements;

[0010] Step S2, pre-burning the precursor solution in an oven to obtain a three-dimensional foam loaded with metal salt;

[0011] Step S3, calcining the obtained three-dimensional foam in air to obtain a low-Ir acidic OER electrocatalyst.

[0012] As a further preferred technical solution of the present application, in step S1, the metal salt comprises iridium chloride and ruthenium chloride, and at least one of aluminum chloride, gallium nitrate, indium nitrate, tin chloride, antimony chloride, bismuth nitrate, and lead nitrate.

[0013] As a further preferred technical solution of the present application, in step S2, the pre-burning temperature is 140-160 ℃, such as 140 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, and the like typical but non-limiting temperatures. It is further preferred that the pre-burning temperature is 150 ℃.

[0014] As a further preferred technical solution of the present application, in step S3, the calcination temperature is 450-700 ℃, such as 450 ℃, 500 ℃, 550 ℃, 600 ℃, 660 ℃, and the like typical but non-limiting temperatures. It is further preferred that the calcination temperature is 500 ℃.

[0015] According to a third aspect of the present application, the present application further provides an application of the low-Ir acidic OER electrocatalyst of the first aspect in hydrogen production by proton exchange membrane electrolysis.

[0016] According to a fourth aspect of the present application, the present application further provides a metal-air battery, the electrode of which employs the low-Ir acidic OER electrocatalyst of the first aspect. Preferably, the metal-air battery is a Zn or Li air battery, specifically, the low-Ir acidic OER electrocatalyst can be loaded on a conductive substrate (such as carbon paper Sigracet GDL 29BC) as an air electrode, and then assembled with an electrolyte (acidic, alkaline or neutral) and a negative electrode (Zn or Li) into a metal-air battery.

[0017] The low-Ir acidic OER electrocatalyst of the present application, by employing the above technical solution, can achieve the following beneficial effects:

[0018] 1) The OER electrocatalyst preparation method of the present application is to obtain a metal salt-loaded three-dimensional foam by taking grape as a template and urea as a gas generator, and then to obtain a catalyst by air calcination. The catalyst exhibits a porous structure macroscopically and is composed of nanoparticles of about 5 nm microscopically, in which the metal M and Ir are uniformly distributed into the crystal lattice of RuO2, thereby optimizing the electronic structure of RuO2.

[0019] 2) The OER electrocatalyst of the present application has a low Ir content, and the Ir loading on the anode of the proton exchange membrane electrolysis is less than 0.1 mg cm -2 , while ensuring the catalytic activity and greatly reducing the cost of the catalyst.

[0020] 3) The electrocatalyst of the present application exhibits excellent activity and stability in acidic OER, with an overpotential of 200-250 mV in acidic OER, and a current density of 100 mA cm -2 Running for 400 h, the overpotential of OER is less than 50 mV, and in addition, it has a lower cell voltage and long-term running stability relative to commercial IrO2 in a proton exchange membrane electrolytic cell, which can reach a current density of 3 A cm -2 at 1.754 V, and can be stably operated for 1000 h at a current density of 1 A cm -2 .

[0021] 4) The OER electrocatalyst of the present application applied to a metal-air battery has a catalytic activity and stability superior to conventional Pt / C, RuO2, and IrO2 electrocatalysts, can significantly enhance the catalytic activity of ORR and OER of the metal-air battery, is conducive to the reaction of oxygen on the surface of the catalyst, and thus improves the electrochemical performance of the metal-air battery. BRIEF DESCRIPTION OF DRAWINGS

[0022] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Figure 1 Morphology characterization of the AlIrRuO2 catalyst of Example 1.

[0024] Figure 2 Structure characterization of the AlIrRuO2 catalyst of Example 1.

[0025] Figure 3 Acidic OER performance characterization of the AlIrRuO2 catalyst of Example 1 and commercial IrO2, RuO2, and IrRuO2 catalysts without doping Al elements.

[0026] Figure 4 Performance characterization of the AlIrRuO2 catalyst of Example 1 and commercial IrO2 catalyst as an anode catalyst for a proton exchange membrane acidic electrolytic water tank.

[0027] The purposes, functional features, and advantages of the present application will be further described with reference to the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0028] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0029] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which this invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are conventional biochemical reagents; the experimental methods described, unless otherwise specified, are conventional methods.

[0030] Example 1

[0031] This embodiment provides a method for preparing a low-Ir acidic OER electrocatalyst, as follows:

[0032] (1) Weigh a certain amount of Al(NO3)3, IrCl3 and RuCl3 and dissolve them in ionized water to make the total concentration of metal salts 0.04 mol / L, of which Al 3+ 、Ir 3+ Ru 3+ The concentrations are 0.004 mol / L, 0.004 mol / L and 0.032 mol / L respectively.

[0033] (2) Glucose and urea were then added and stirred continuously to obtain a clear solution with a glucose concentration of 6 mol / L and a urea concentration of 3 mol / L.

[0034] (3) The beaker was then placed in an oven and pre-calcined at 150 °C for 10 h to obtain a three-dimensional metal salt-loaded glucose foam.

[0035] (4) Finally, the obtained foam was placed in a muffle furnace and calcined at 500 °C for 12 h in air. After washing with deionized water and drying, the AlIrRuO2 catalyst was obtained.

[0036] Figure 1 Morphological characterization of AlIrRuO2 catalyst. TEM ( Figure 1 a) shows that the catalyst has a porous structure, HRTEM ( Figure 1 b) shows that the catalyst is composed of small particles of about 5 nanometers.

[0037] Figure 2 The XRD pattern shows that the peak positions of the AlIrRuO2 catalyst correspond exactly to those of pure RuO2, with no other impurity peaks, proving that Al and Ir have entered the RuO2 lattice.

[0038] Example 2

[0039] This embodiment provides a method for preparing a low-Ir acidic OER electrocatalyst, as follows:

[0040] (1) A certain amount of Ga(NO3)3, IrCl3 and RuCl3 are dissolved in ionized water to make the total concentration of metal salt 0.04 mol / L, in which the concentrations of Ga 3+ , Ir 3+ and Ru 3+ are 0.002 mol / L, 0.002 mol / L and 0.036 mol / L respectively.

[0041] (2) Then glucose and urea are added, and a clear solution is obtained after continuous stirring, with the concentration of glucose being 6 mol / L and the concentration of urea being 3 mol / L.

[0042] (3) Subsequently, the beaker is placed in an oven and pre-burned at a temperature of 150 ℃ for 10 h to obtain a three-dimensional metal salt loaded glucose foam.

[0043] (4) Finally, the obtained foam is placed in a muffle furnace and calcined at 500 ℃ under air for 12 h, and then washed and dried with deionized water to obtain a GaIrRuO2 catalyst.

[0044] Example 3

[0045] The preparation method of the low-Ir acidic OER electrocatalyst provided in this embodiment is as follows:

[0046] (1) A certain amount of In(NO3)3, SnCl4, IrCl3 and RuCl3 are dissolved in ionized water to make the total concentration of metal salt 0.04 mol / L, in which the concentrations of In 3+ , Sn 4+ , Ir 3+ and Ru 3+ are 0.002 mol / L, 0.002 mol / L, 0.004 mol / L and 0.032 mol / L respectively.

[0047] (2) Then glucose and urea are added, and a clear solution is obtained after continuous stirring, with the concentration of glucose being 6 mol / L and the concentration of urea being 3 mol / L.

[0048] (3) Subsequently, the beaker is placed in an oven and pre-burned at a temperature of 150 ℃ for 10 h to obtain a three-dimensional metal salt loaded glucose foam.

[0049] (4) Finally, the obtained foam is placed in a muffle furnace and calcined at 500 ℃ under air for 12 h, and then washed and dried with deionized water to obtain an InSnIrRuO2 catalyst.

[0050] Example 4

[0051] The embodiment provides a preparation method of a low-Ir acidic OER electrocatalyst, and specifically as follows.

[0052] (1) A certain amount of SbCl3, IrCl3 and RuCl3 are dissolved in ionized water, so that the total concentration of metal salts is 0.04 mol / L, wherein the concentrations of Sb 3+ , Ir 3+ and Ru 3+ are 0.008 mol / L, 0.008 mol / L and 0.024 mol / L respectively.

[0053] (2) Then, glucose and urea are added, and a clear solution is obtained through continuous stirring, wherein the concentration of glucose is 6 mol / L, and the concentration of urea is 3 mol / L.

[0054] (3) Then, the beaker is placed into an oven and pre-burned at a temperature of 150 DEG C for 10 h, so as to obtain a three-dimensional metal salt loaded glucose foam.

[0055] (4) Finally, the obtained foam is placed into a muffle furnace and calcined at 500 DEG C under air for 12 h, and then washed with deionized water and dried, so as to obtain a SbIrRuO2 catalyst.

[0056] Example 5

[0057] The embodiment provides a preparation method of a low-Ir acidic OER electrocatalyst, and specifically as follows.

[0058] (1) A certain amount of Bi(NO3)3, IrCl3 and RuCl3 are dissolved in ionized water, so that the total concentration of metal salts is 0.04 mol / L, wherein the concentrations of Bi 3+ , Ir 3+ and Ru 3+ are 0.004 mol / L, 0.004 mol / L and 0.032 mol / L respectively.

[0059] (2) Then, glucose and urea are added, and a clear solution is obtained through continuous stirring, wherein the concentration of glucose is 6 mol / L, and the concentration of urea is 3 mol / L.

[0060] (3) Then, the beaker is placed into an oven and pre-burned at a temperature of 150 DEG C for 10 h, so as to obtain a three-dimensional metal salt loaded glucose foam.

[0061] (4) Finally, the obtained foam is placed into a muffle furnace and calcined at 500 DEG C under air for 12 h, and then washed with deionized water and dried, so as to obtain a BiIrRuO2 catalyst.

[0062] Example 6

[0063] This embodiment provides a method for preparing a low-Ir acidic OER electrocatalyst, as follows:

[0064] (1) Weigh a certain amount of Pb(NO3)2, IrCl3 and RuCl3 and dissolve them in ionized water to make the total concentration of metal salts 0.04 mol / L, of which Pb 2+ 、Ir 3+ Ru 3+ The concentrations are 0.012 mol / L, 0.008 mol / L and 0.02 mol / L respectively.

[0065] (2) Glucose and urea were then added and stirred continuously to obtain a clear solution with a glucose concentration of 6 mol / L and a urea concentration of 3 mol / L.

[0066] (3) The beaker was then placed in an oven and pre-calcined at 150 °C for 10 h to obtain a three-dimensional metal salt-loaded glucose foam.

[0067] (4) Finally, the obtained foam was placed in a muffle furnace and calcined at 500 °C for 12 h in air. After washing with deionized water and drying, the PbIrRuO2 catalyst was obtained.

[0068] Example 7

[0069] This embodiment provides a method for preparing a low-Ir acidic OER electrocatalyst, as follows:

[0070] (1) Weigh a certain amount of Pb(NO3)2, Ga(NO3)3, IrCl3 and RuCl3 and dissolve them in ionized water to make the total concentration of metal salts 0.04 mol / L, of which Pb 2+ , Ga 3+ , Ir 3+ Ru 3+ The concentrations are 0.004 mol / L, 0.004 mol / L, 0.008 mol / L and 0.024 mol / L respectively.

[0071] (2) Glucose and urea were then added and stirred continuously to obtain a clear solution with a glucose concentration of 6 mol / L and a urea concentration of 3 mol / L.

[0072] (3) The beaker was then placed in an oven and pre-calcined at 150 °C for 10 h to obtain a three-dimensional metal salt-loaded glucose foam.

[0073] (4) Finally, the obtained foam was placed in a muffle furnace and calcined at 500 °C for 12 h in air. After washing with deionized water and drying, the PbGaIrRuO2 catalyst was obtained.

[0074] Experimental test:

[0075] I. The test method for testing the OER performance of the catalyst prepared in the above examples is as follows:

[0076] (1) First, prepare the MlrRuO2 catalyst slurry, and the preparation method is as follows: add 5 mg of catalyst to 1 mL of isopropyl alcohol solution containing 25 μL of naphthol, and obtain a uniform black catalyst slurry after ultrasonic treatment for 30 minutes.

[0077] (2) Take 200 μL of the black catalyst slurry and drop it on a carbon paper with a surface area of 1 cm 2 , and dry at room temperature.

[0078] (3) Test using a three-electrode battery, with carbon paper as the working electrode, platinum wire as the counter electrode, Hg / Hg2SO4 as the reference electrode, and 0.5 M H2SO4 as the electrolyte. The test voltage range is 1.2-1.6 V vs. RHE.

[0079] In the OER performance test, as a comparison, the OER performance of commercial IrO2, RuO2, and IrRuO2 catalyst without doping M element was tested under the same test conditions. The test results show that the MlrRuO2 catalyst of the present application has stronger catalytic activity than the commercial catalyst, and has very high stability.

[0080] II. The method for testing the catalyst prepared in the above examples as a proton exchange membrane acidic electrolytic water is as follows:

[0081] (1) First, prepare the MlrRuO2 catalyst slurry, and the preparation method is as follows: add 20 mg of catalyst to 4 mL of isopropyl alcohol and water mixed solution containing 100 μL of naphthol, and obtain a uniform black catalyst slurry after ultrasonic treatment for 30 minutes.

[0082] (2) Prepare the Pt / C catalyst slurry, and the preparation method is as follows: add 10 mg of catalyst to 4 mL of isopropyl alcohol and water mixed solution containing 60 μL of naphthol, and obtain a uniform black catalyst slurry after ultrasonic treatment for 30 minutes.

[0083] (3) Membrane electrode preparation: spray the MlrRuO2 and Pt / C catalyst slurries on both sides of the proton exchange membrane, and the MlrRuO2 and Pt loadings are 1.5 mg cm -2 and 0.3 mg cm -2 , respectively.

[0084] (4) Assemble the titanium felt, membrane electrode, carbon paper, and bipolar plate into an electrolytic cell, and test in a battery test system, with circulating deionized water, a test temperature of 70°C, and a test voltage range of 1.2 V-2.0 V.

[0085] As a comparison, commercial IrO2 was prepared into slurry by the method of step (1) above, and was sprayed together with the Pt / C catalyst slurry prepared by the method of step (2) above on both sides of a proton exchange membrane, the loading of commercial IrO2 was 1 mg cm -2 , the loading of Pt was 0.3 mg cm -2 , and then performance test was carried out.

[0086] The results of testing the catalyst of Example 1 according to the above testing method are shown in Figure 3 and Figure 4 .

[0087] Figure 3 The acid OER performance characterization of the AlIrRuO2 catalyst. From a) in Figure 3 , it can be seen that the overpotential of the catalyst is only 203 mV at 10 mA cm -2 , which is much lower than the 281 mV of the commercial RuO2 catalyst. Figure 3 , b shows that the AlIrRuO2 catalyst runs for 400 h at a current density of 100 mA cm -2 , and the overpotential increases only by about 30 mV, which is superior to the commercial RuO2, IrO2 and IrRuO2 catalysts without doping Al element.

[0088] Figure 4 The performance characterization of the AlIrRuO2 catalyst as an anode catalyst for a proton exchange membrane acid electrolysis water tank. From a in Figure 4 , it can be seen that when the AlIrRuO2 catalyst is used as an anode material, the voltage required to reach a current density of 1 A cm -2 is 0.171 V lower than that of the commercial IrO2 material at an Ir loading of only 0.1 mg cm -2 , and the voltage required to reach a current density of 3 A cm -2 is only 1.754 V, which is much lower than the target set by the U.S. Department of Energy in 2025 to reach a current density of 3 A cm -2 at 1.9 V, and at 1.958 V, it can reach an ultra-high current density of 5 A cm -2 . From b in Figure 4 , it can be seen that when the electrolysis tank works at a current density of 1 A cm -2 , the voltage does not increase significantly after running for 1000 h, which proves that the catalyst has excellent stability as an anode for a proton exchange membrane acid electrolysis water tank.

[0089] The performance parameters of the catalysts obtained in Examples 1-7 above are summarized in Table 1.

[0090] Table 1

[0091] 3. The catalyst prepared in the above examples was used for oxygen reduction activity test:

[0092] The electrochemical performance was evaluated at room temperature using a CHI 760E electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd.) with a three-electrode setup. A rotating ring disk electrode (RRDE-3A) with an area of ​​0.0707 cm was used as the working electrode. 2 A saturated calomel electrode (SCE) (3.0 mm in diameter) was used as the reference electrode and a carbon rod as the counter electrode. The surface of the glassy carbon electrode was polished before the electrochemical reaction test. 5 mg of MIrRuO2 catalyst was dispersed in a mixed solution of 250 μL of ultrapure water and 250 μL of ethanol, and 25 μL of (0.05%) Nafion adhesive was added and ultrasonicated for 30 minutes to obtain a slurry; then 2 μL of the slurry was evenly drop-coated on the working electrode and dried at room temperature. At the same time, a commercial Pt / C (20%) catalyst was used as a control group and compared in the same manner. The oxygen reduction test was carried out in 0.5 M H2SO4 saturated with O2 in the potential range of -0.9 to 0.2 V (relative to Hg / Hg2Cl2). The rotation speed was 1600 rpm and the reaction temperature was 10 mV·s -1 Linear sweep voltammetry (LSV) curves were measured at a scan rate of 100 nm. The results showed that under acidic conditions, the half-wave potential of the AlIrRuO2 catalyst prepared in Example 1 was approximately 0.79 V, comparable to that of a Pt / C catalyst and demonstrating excellent catalytic performance. After 800 cycles, the catalytic activity of the AlIrRuO2 catalyst remained virtually unchanged, demonstrating extremely high stability. In contrast, the performance of the commercial Pt / C catalyst declined significantly, indicating its poor stability.

[0093] The low-Ir acidic OER electrocatalyst of the present invention has superior electrocatalytic performance compared to conventional Pt / C, RuO2, IrO2, etc., exhibiting excellent OER performance and oxygen reduction reaction (ORR). This makes the low-Ir acidic OER electrocatalyst of the present invention applicable to metal-air batteries, where it exhibits excellent electrochemical performance. Due to the slow kinetics of the OER reaction, conventional batteries require a long time to complete this step during charging, resulting in low charging efficiency. By using the low-Ir acidic OER electrocatalyst of the present invention, the speed of this reaction can be significantly increased, thereby speeding up the charging process and improving the overall performance of the battery.

[0094] Although the specific embodiments of the present application have been described above, it is understood by those skilled in the art that these are merely illustrative and various changes or modifications can be made to the present embodiments without departing from the principles and the spirit of the present application, and the scope of protection of the present application is defined only by the appended claims.

Claims

1. A low Ir acidic OER electrocatalyst for metal-air battery electrodes, characterized in that The electrocatalyst component M x Ir y Ru 1-x-y O2, where M is one or more of the metal elements Al, Ga, In, Sn, Sb, Bi, and Pb, 0 <x<0.3,0<y<0.2。 2. The low Ir acidic OER electrocatalyst for metal-air battery electrodes according to claim 1, characterized in that The content of M in the electrocatalyst component is 0.1-30 at%, the content of Ir is 0.1-20 at%, and the content of Ru is 50-99.8 at%.

3. A method for preparing a low Ir acidic OER electrocatalyst for metal-air battery electrodes according to claim 1 or 2, characterized in that: The following steps are involved: S1. Mixing a metal salt, glucose, and urea to form a uniform precursor solution, wherein the metal salt contains metal elements M, Ir, and Ru, wherein M is one or more of Al, Ga, In, Sn, Sb, Bi, and Pb; S2, pre-calcining the precursor solution to obtain a three-dimensional foam supported by a metal salt; S3. The obtained three-dimensional foam is calcined in air to obtain a low Ir acidic OER electrocatalyst.

4. The preparation method according to claim 3, characterized in that In step S1, the metal salt includes iridium chloride and ruthenium chloride, and at least one of aluminum chloride, gallium nitrate, indium nitrate, tin chloride, antimony chloride, bismuth nitrate, and lead nitrate.

5. The preparation method according to claim 3, characterized in that In step S2, the pre-firing temperature is 140-160°C.

6. The preparation method according to claim 3, characterized in that In step S3, the calcination temperature is 450-700°C.

7. Use of the low Ir acidic OER electrocatalyst for metal-air battery electrodes according to claim 1 or 2 in hydrogen production in a proton exchange membrane electrolyzer.

8. A metal-air battery, characterized in that: The electrode of the metal-air battery adopts the low-Ir acidic OER electrocatalyst for the metal-air battery electrode according to claim 1 or 2.

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