An iridium-based catalyst, its preparation method and application

Abstract

This invention discloses an iridium-based catalyst, its preparation method, and its applications. The catalyst comprises an active component and a support; wherein the active component includes iridium and at least one transition metal selected from iron, cobalt, and nickel; and the support is a nitrogen-doped carbon material. The catalyst of this invention has the advantages of a large electrochemical active surface area, high catalytic activity for the oxygen evolution reaction, and good stability, making it suitable for the oxygen evolution reaction under acidic conditions.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis, specifically relating to an iridium-based catalyst and its preparation method, as well as its application in the oxygen evolution reaction. Background Technology

[0002] Hydrogen energy, as a clean and renewable energy source, has attracted much attention, and water electrolysis is one of the most commonly used methods for hydrogen production. Water electrolysis decomposes water molecules into hydrogen and oxygen, with the oxygen evolution reaction at the anode being a crucial component. Iridium catalysts are commonly used in the oxygen evolution reaction, but the extremely low abundance of iridium in the Earth's crust limits the large-scale application of water electrolysis technology. To further improve the efficiency of iridium catalysts and reduce the amount of precious metals used, alloying is a feasible method. Alloying can improve the stability and activity of the catalyst and, to some extent, reduce the amount of precious metals required.

[0003] Some progress has been made in iridium-based alloy catalysts. CN110453256B discloses a polyhedral cobalt-iridium nanoparticle catalyst prepared by electrochemical deposition; CN112475314A discloses an iridium-based nanowire prepared by a chemical synthesis method using a mixed solvent, with nanowire diameters ranging from 20 to 100 nm. The catalysts disclosed above exhibit better oxygen evolution reaction performance than iridium nanocatalysts. However, the above synthesis processes are generally not conducive to scale-up and pilot production. Large-particle-size, large-cross-section nanowires often have lower electrochemically active surface areas, and the catalyst performance needs further improvement. Summary of the Invention

[0004] The purpose of this invention is to provide an iridium-based catalyst, its preparation method, and its application. This catalyst has the advantages of large electrochemical active surface area, high catalytic activity in the oxygen evolution reaction, and good stability, and is suitable for the oxygen evolution reaction under acidic conditions.

[0005] The first aspect of the present invention provides an iridium-based catalyst, the catalyst comprising an active component and a support;

[0006] The active component includes iridium and at least one transition metal selected from iron, cobalt, and nickel; the support is a nitrogen-doped carbon material.

[0007] Furthermore, the active component is twinned nanowires.

[0008] Furthermore, the diameter d of the nanowire is 0.5 to 5 nm, and the twin grain size of the nanowire is (0.8 to 1.1)·d nm.

[0009] Furthermore, the atomic ratio of iridium to transition metal in the active component is 1:(0.1-5), preferably 1:(0.2-3).

[0010] Furthermore, the nitrogen-doped carbon material is selected from at least one of nitrogen-doped carbon black, nitrogen-doped graphene, and nitrogen-doped carbon nanotubes.

[0011] Furthermore, the molar content of nitrogen in the nitrogen-doped carbon material is 0.5% to 5%.

[0012] Further, by weight, the catalyst comprises 10 to 95 parts of active component and 5 to 90 parts of nitrogen-doped carbon material support, preferably containing 20 to 90 parts of active component and 10 to 80 parts of nitrogen-doped carbon material support.

[0013] Furthermore, the electrochemical surface area of ​​the catalyst is 36–78 cm². 2 For example, it could be 40cm 2 45cm 2 50cm 2 55cm 2 60cm 2 65cm 2 70cm 2 75cm 2 The values ​​may include, but are not limited to, the listed values; other unlisted values ​​within this range also apply. The electrochemical surface area of ​​the catalyst is preferably 38–78 cm². 2 .

[0014] A second aspect of the present invention provides a method for preparing the above-mentioned iridium-based catalyst, comprising the following steps:

[0015] (1) Mix iridium source and transition metal source, surfactant, crystal plane coordination agent and organic alcohol, and heat to react to obtain iridium-based nanowire active component;

[0016] (2) The nitrogen-doped carbon material is mixed with the iridium-based nanowire active component and then subjected to atmospheric heat treatment to obtain the iridium-based catalyst.

[0017] Further, the iridium source in step (1) is selected from at least one of iridium chloride, iridium acetylacetonate, iridium carbonyl, hexachloroiridic acid, sodium hexachloroiridate, and ammonium hexachloroiridate.

[0018] Further, the transition metal source mentioned in step (1) is selected from at least one of the soluble chlorides, bromides, nitrates, sulfates, carbonates, acetates, and acetylacetone salts corresponding to the transition metals iron, cobalt, and nickel.

[0019] Further, the surfactant mentioned in step (1) is polyvinylpyrrolidone.

[0020] Furthermore, the crystal plane coordination reagent mentioned in step (1) is a quaternary ammonium salt containing bromide ions and an inorganic iodide;

[0021] More preferably, the bromide-containing quaternary ammonium salt is selected from at least one of tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, hexadecyltrimethylammonium bromide, and benzyltriethylammonium bromide;

[0022] More preferably, the inorganic iodide is selected from at least one of sodium iodide, potassium iodide, and ammonium iodide.

[0023] Further, the organic alcohol in step (1) is preferably a polyol, more preferably a diol and / or a triol; preferably, the polyol is selected from at least one of ethylene glycol, 1,2-propanediol, 1,3-propanediol, glycerol, diethylene glycol, and triethylene glycol.

[0024] Further, the molar ratio of the iridium source, transition metal source, and crystal plane coordination reagent in step (1) is 1:(0.5-15):(5.1-32), preferably 1:(0.5-10):(5.1-32); preferably, the molar ratio of the iridium source, the quaternary ammonium salt containing bromide ions, and the inorganic iodide of the crystal plane coordination reagent in step (1) is 1:(5-30):(0.1-1.2).

[0025] Further, in step (1), the mass ratio of the iridium source (converted based on hydrated iridium chloride), surfactant, and organic alcohol is 1:(8-12):(1500-1800).

[0026] Further, the heating in step (1) is preferably carried out under sealed conditions; optionally, the polyol solvothermal reaction is carried out under heating conditions; optionally, the heating temperature is 130-230℃, preferably 160-190℃; the time is 4-60h, preferably 24-48h; and the pressure is 0.8-1.5bar, preferably 0.8-1.2bar. Further, after the heating reaction in step (1), the purified iridium-based nanowires can be obtained by conventional post-processing steps in the art (such as centrifugation, washing, and drying). Among them, the centrifugation operation step is, for example, but not limited to, adding acetone to the product obtained after the heating reaction and centrifuging; the washing and drying operation steps are, for example, but not limited to, ultrasonically dispersing the black precipitate after centrifugation with ethanol, adding acetone and centrifuging and washing, repeating the above steps several times, and drying to obtain the purified iridium-based nanowires.

[0027] Further, the method for nitrogen doping the carbon support in step (2) is to dope the carbon support with nitrogen source through solid-phase or liquid-phase reaction, preferably solid-phase doping. The specific steps of the solid-phase doping method are to fully mix the carbon support and nitrogen source powder, and heat under an oxidizing atmosphere to obtain nitrogen-doped carbon support powder. The mass ratio of the carbon support and nitrogen source powder is 1:0.2 to 5.

[0028] Furthermore, the nitrogen source in the nitrogen doping can be a conventional nitrogen source disclosed in the art, such as, but not limited to, at least one of urea, biuret, ammonium nitrate, ammonium bicarbonate, and melamine.

[0029] Furthermore, the carbon support in the nitrogen-doped carbon material is at least one of carbon black, graphene, carbon nanotubes, and activated carbon. Optionally, the carbon support may undergo oxidation pretreatment.

[0030] Further, the nitrogen-doped atmosphere is an oxygen atmosphere with an oxygen content of 5 vol% to 20 vol%. In the oxidizing atmosphere, besides oxygen, the remainder is at least one of nitrogen and / or an inert gas, wherein the inert gas is selected from at least one of argon and helium. The heating temperature is 150–350°C, preferably 200–350°C, and the time is 0.5–6 h, preferably 0.5–4 h.

[0031] Further, in step (2), a dispersion containing the iridium-based nanowire metallic active component from step (1) is first prepared, and then mixed with a nitrogen-doped carbon support. Optionally, after mixing, the mixture is sonicated, centrifuged, and dried to obtain a solid powder.

[0032] Further, the dispersion in step (2) is ethanol and / or isopropanol containing iridium-based nanowire metal active components, and the mass fraction of the metal active components in the dispersion is 0.2% to 2%.

[0033] Furthermore, in step (2), the mass ratio of the iridium-based nanowire active component to the nitrogen-doped carbon support is 10–95:5–90, preferably 20–90:10–80.

[0034] Furthermore, the ultrasound time in step (2) is 8 to 24 hours; the drying temperature is 60 to 120°C and the time is 4 to 12 hours.

[0035] Further, the atmosphere heat treatment in step (2) is to treat in an oxidizing atmosphere at 200-350°C for 0.5-4 hours.

[0036] Furthermore, the oxygen content in the oxidizing atmosphere described in step (2) is 5 vol% to 20 vol%.

[0037] Furthermore, in the oxidizing atmosphere described in step (2), apart from oxygen, the remaining gas is at least one of nitrogen and / or an inert gas, wherein the inert gas is selected from at least one of argon and helium.

[0038] The third aspect of this invention is the application of the catalyst described above in the oxygen evolution reaction under acidic conditions.

[0039] Furthermore, the oxygen evolution reaction under acidic conditions can be an anodic oxygen evolution reaction caused by the electrolysis of water or the electroreduction of carbon dioxide under acidic conditions.

[0040] Furthermore, the acidic oxygen evolution reaction includes oxygen evolution reactions occurring on the surface of the polymer electrolyte membrane and in the acidic solution.

[0041] Furthermore, the polymer electrolyte membrane includes at least one of perfluorosulfonic acid proton exchange membrane, partially fluorinated polymer proton exchange membrane, non-fluorinated polymer proton exchange membrane, and composite membrane.

[0042] Furthermore, the acidic solution is selected from at least one of perchloric acid and sulfuric acid, and the concentration of the acidic solution is 0.01 to 2 mol / L.

[0043] Furthermore, the acidic solution is an oxygen-saturated acidic solution at 20–80°C.

[0044] The present invention has the following beneficial effects:

[0045] In the iridium-based catalyst of this invention, the active component is twinned nanowires, which have a large electrochemical surface area. This active component not only significantly reduces the amount of precious metal iridium used, but also exhibits excellent catalytic activity and stability for the oxygen evolution reaction. Furthermore, the preparation method provided by this invention is simple, has minimal environmental impact, and produces iridium-based catalysts with uniform size, making them suitable for large-scale production. Attached Figure Description

[0046] Figure 1 This is a high-resolution TEM image of the iridium-based nanowires, the active component of Example 1.

[0047] Figure 2 This is a TEM image of the iridium-based nanocrystals, the active component of Comparative Example 3. Detailed Implementation

[0048] The following embodiments will further illustrate the technical solutions provided by the present invention, but the scope of protection of the present invention is not limited to these embodiments.

[0049] In the following examples, 0.5 mol·L⁻¹ oxygen saturated at 25°C was used. -1 In a sulfuric acid solution, a three-electrode system was tested using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode. The catalyst and a solution of the perfluorosulfonic acid-based polymer Nafion were dispersed in water / ethanol / isopropanol and ultrasonically dispersed to obtain a catalyst slurry. The catalyst slurry was then dropped onto the surface of the rotating disk electrode and dried to obtain a thin-film electrode. The oxygen evolution reaction current at a reaction overpotential of 0.25 V was used as a reference to compare the oxygen evolution reaction activity of the catalyst. The catalyst activity at 10 mA·cm⁻¹ was also compared.-2 The time required for stable operation at a given current density is used as an evaluation criterion for catalyst stability.

[0050] In this invention, the diameter of the nanowire is measured using transmission electron microscopy (TEM) images. The TEM accelerating voltage is 200–300 kV, and the magnification is 200–1500 k×. The length perpendicular to the nanowire axis in the TEM image is measured using Nano Measurer software. The results of 200 measurements at different locations are statistically analyzed, and the average value and standard deviation are calculated to obtain the diameter of the nanowire.

[0051] Example 1

[0052] 2.5 g of polyvinylpyrrolidone (PVP), 1 mmol of iridium chloride hydrate, and 2 mmol of cobalt chloride hexahydrate were added to 475 g of ethylene glycol and stirred until completely dissolved. Then, 12 mmol of tetraethylammonium bromide and 0.5 mmol of potassium iodide were added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 190 °C and 1 bar for 48 h. The resulting product was centrifuged with acetone, and the resulting black precipitate was dispersed ultrasonically with ethanol. The precipitate was then washed with acetone by centrifugation, and the above steps were repeated several times. The purified iridium-cobalt nanowires were obtained by drying. The ratio of iridium atoms to cobalt atoms was 1:0.6. A TEM image of the iridium-cobalt nanowires is shown below. Figure 1 ,pass Figure 1 It can be seen that the nanowires have a narrow size distribution and exhibit a twinned structure. The nanowire diameter d is 3.5 ± 0.3 nm, and the twin grain size of the nanowires is 3.4 nm.

[0053] The steps for obtaining nitrogen-doped graphene are as follows: 1g of graphene oxide and 4g of urea are thoroughly ground and mixed, heated at 250°C for 2 hours in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium, and then cooled to obtain nitrogen-doped graphene powder.

[0054] 46 mg of iridium-cobalt nanowires were dispersed in 50 mL of ethanol, 85 mg of nitrogen-doped graphene was added, and the mixture was sonicated for 12 h. After centrifugation, a black precipitate was obtained and dried in an oven at 80 °C for 8 h to obtain a black solid powder. The solid powder was then treated at 250 °C in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium for 2.5 h to obtain an iridium-cobalt nanowire catalyst.

[0055] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 54.4 cm² in a three-electrode system. 2 The catalyst specific activity is 113.0 μA / cm.2 At 10mA·cm -2 It operated stably for 32 hours at the specified current density.

[0056] Example 2

[0057] 3.5 g of polyvinylpyrrolidone (PVP), 1 mmol of iridium acetylacetone, and 4 mmol of ferrous sulfate heptahydrate were added to 500 g of ethylene glycol and stirred until completely dissolved. Then, 5 mmol of tetramethylammonium bromide and 0.3 mmol of sodium iodide were added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 180 °C and 0.8 bar for 36 h. The resulting product was centrifuged with acetone, and the resulting black precipitate was dispersed ultrasonically with ethanol. The precipitate was then washed with acetone by centrifugation, and the above steps were repeated several times. The purified iridium-iron nanowires were obtained by drying. The ratio of iridium atoms to iron atoms was 1:1.2. TEM images of the iridium-iron nanowires are shown below. Figure 1 Similarly, the nanowires exhibit a narrow size distribution and a twinned structure. The nanowire diameter d is 3.7 ± 0.3 nm, and the twin grain size of the nanowires is 3.5 nm.

[0058] The steps for obtaining nitrogen-doped graphene are as follows: 1g of graphene oxide and 3g of melamine are thoroughly ground and mixed, heated at 350°C for 4 hours in an oxidizing atmosphere containing 20 vol% oxygen and 80 vol% helium, and then cooled to obtain nitrogen-doped graphene powder.

[0059] 57 mg of iridium-iron nanowires were dispersed in 50 mL of isopropanol, 85 mg of nitrogen-doped graphene was added, and the mixture was sonicated for 10 h. After centrifugation, a black precipitate was obtained and dried in an oven at 70 °C for 6 h to obtain a black solid powder. The solid powder was then treated at 250 °C in an oxidizing atmosphere containing 15 vol% oxygen and 85 vol% nitrogen for 1.5 h to obtain an iridium-iron nanowire catalyst.

[0060] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 51.4 cm² in a three-electrode system. 2 The catalyst specific activity is 125.4 μA / cm. 2 At 10mA·cm -2 It operates stably for 25 hours at the specified current density.

[0061] Example 3

[0062] 3 g of polyvinylpyrrolidone (PVP), 0.25 mmol of tetrairidium dodecylcarbonyl and 0.5 mmol of nickel bromide hydrate were added to 525 g of glycerol and stirred until completely dissolved. Then, 8 mmol of tetraethylammonium bromide and 0.1 mmol of ammonium iodide were added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 170 °C and 0.9 bar for 30 h. The resulting product was centrifuged with acetone, and the resulting black precipitate was dispersed ultrasonically with ethanol. The precipitate was then washed with acetone by centrifugation, and the above steps were repeated several times. The purified iridium-nickel nanowires were obtained by drying. The ratio of iridium atoms to nickel atoms was 1:0.2. TEM images of the iridium-nickel nanowires are shown below. Figure 1 Similarly, the nanowires exhibit a narrow size distribution and a twinned structure. The nanowire diameter d is 1.4 ± 0.2 nm, and the twin grain size of the nanowires is 1.2 nm.

[0063] The steps for nitrogen-doped carbon nanotubes are as follows: 1g of carbon oxide nanotubes and 2g of ammonium bicarbonate are thoroughly ground and mixed, heated at 320°C for 3h in an oxidizing atmosphere containing 20 vol% oxygen and 80 vol% helium, and then cooled to obtain nitrogen-doped carbon nanotube powder.

[0064] 21 mg of iridium-nickel nanowires were dispersed in 50 mL of isopropanol, 85 mg of nitrogen-doped carbon nanotubes were added, and the mixture was sonicated for 20 h. After centrifugation, a black precipitate was obtained and dried in an oven at 120 °C for 12 h to obtain a black solid powder. The solid powder was then treated at 240 °C in an oxidizing atmosphere containing 20 vol% oxygen and 80 vol% argon for 2 h to obtain the iridium-nickel nanowire catalyst.

[0065] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 67.1 cm² in a three-electrode system. 2 The catalyst specific activity is 97.1 μA / cm. 2 At 10mA·cm -2 It operated stably for 29 hours at the specified current density.

[0066] Example 4

[0067] 3 g of polyvinylpyrrolidone (PVP), 1 mmol of iridium acetylacetone, and 1 mmol of basic nickel carbonate were added to 550 g of glycerol and stirred until completely dissolved. Then, 15 mmol of tetrabutylammonium bromide and 0.7 mmol of potassium iodide were added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 160 °C and 1.1 bar for 24 h. The resulting product was centrifuged with acetone, and the resulting black precipitate was dispersed ultrasonically with ethanol. The precipitate was then washed with acetone by centrifugation, and the above steps were repeated several times. The purified iridium-nickel nanowires were obtained by drying. The ratio of iridium atoms to nickel atoms was 1:0.3. TEM images of the iridium-nickel nanowires are shown below. Figure 1 Similarly, the nanowires exhibit a narrow size distribution and a twinned structure. The nanowire diameter d is 2.2 ± 0.2 nm, and the twin grain size of the nanowires is 2.2 nm.

[0068] The steps for nitrogen-doped carbon black are as follows: 1g of carbon black and 1g of biuret are thoroughly ground and mixed, heated at 300°C for 2 hours in an oxidizing atmosphere containing 15 vol% oxygen and 85 vol% helium, and then cooled to obtain nitrogen-doped carbon black powder.

[0069] 26 mg of iridium-nickel nanowires were dispersed in 50 mL of ethanol, 85 mg of nitrogen-doped carbon black was added, and the mixture was sonicated for 15 h. After centrifugation, a black precipitate was obtained and dried in an oven at 100 °C for 10 h to obtain a black solid powder. The solid powder was then treated at 300 °C in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% argon for 4 h to obtain the iridium-nickel nanowire catalyst.

[0070] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 60.5 cm² in a three-electrode system at a reaction overpotential of 0.25 V. 2 The catalyst specific activity is 102.9 μA / cm. 2 At 10mA·cm -2 It operated stably for 37 hours at the specified current density.

[0071] Example 5

[0072] 3.8 g of polyvinylpyrrolidone (PVP), 1 mmol of iridium chloride hydrate, and 10 mmol of ferric acetylacetone were added to 560 g of 1,2-propanediol and stirred until completely dissolved. Then, 20 mmol of tetramethylammonium bromide and 0.9 mmol of sodium iodide were added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 170 °C and 1 bar for 36 h. The resulting product was centrifuged with acetone, and the resulting black precipitate was dispersed ultrasonically with ethanol. The precipitate was then washed with acetone by centrifugation. This process was repeated several times, and the purified iridium-iron nanowires were obtained after drying. The ratio of iridium atoms to iron atoms was 1:3. TEM images of the iridium-iron nanowires are shown below. Figure 1 Similarly, the nanowires exhibit a narrow size distribution and a twinned structure. The nanowire diameter d is 4.6 ± 0.5 nm, and the twin grain size of the nanowires is 4.9 nm.

[0073] The steps for nitrogen-doped carbon black are as follows: 1g of carbon black and 0.5g of biuret are thoroughly ground and mixed, heated at 200°C for 0.5h in an oxidizing atmosphere containing 5vol% oxygen and 95vol% helium, and then cooled to obtain nitrogen-doped carbon black powder.

[0074] 340 mg of iridium-iron nanowires were dispersed in 50 mL of ethanol, 85 mg of nitrogen-doped carbon black was added, and the mixture was sonicated for 18 h. After centrifugation, a black precipitate was obtained and dried in an oven at 110 °C for 10 h to obtain a black solid powder. The solid powder was then treated at 270 °C in an oxidizing atmosphere containing 15 vol% oxygen and 85 vol% helium for 3 h to obtain an iridium-iron nanowire catalyst.

[0075] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 42.7 cm² in a three-electrode system. 2 The catalyst specific activity is 109.6 μA / cm. 2 At 10mA·cm -2 It operated stably for 41 hours at the specified current density.

[0076] Example 6

[0077] 2.75 g of polyvinylpyrrolidone (PVP), 1 mmol of iridium acetylacetone, and 3 mmol of cobalt octacarbonyl were added to 570 g of 1,2-propanediol and stirred until completely dissolved. Then, 30 mmol of tetrabutylammonium bromide and 1.1 mmol of ammonium iodide were added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 180 °C and 1 bar for 30 h. The resulting product was centrifuged with acetone, and the resulting black precipitate was dispersed ultrasonically with ethanol. The precipitate was then washed with acetone by centrifugation, and the above steps were repeated several times. The purified iridium-cobalt nanowires were obtained by drying. The ratio of iridium atoms to cobalt atoms was 1:2. TEM images of the iridium-cobalt nanowires are shown below. Figure 1 Similarly, the nanowires exhibit a narrow size distribution and a twinned structure. The nanowire diameter d is 4.1 ± 0.4 nm, and the twin grain size of the nanowires is 4.5 nm.

[0078] The steps for obtaining nitrogen-doped carbon nanotubes are as follows: 1g of carbon black and 2.5g of urea are thoroughly ground and mixed, heated at 270°C for 1 hour in an oxidizing atmosphere containing 15 vol% oxygen and 85 vol% helium, and then cooled to obtain nitrogen-doped carbon nanotubes.

[0079] 128 mg of iridium-cobalt nanowires were dispersed in 50 mL of ethanol, and 85 mg of nitrogen-doped carbon nanotubes were added. The mixture was ultrasonically treated for 22 h, and centrifuged to obtain a black precipitate. The precipitate was dried in an oven at 60 °C for 4 h to obtain a black solid powder. The solid powder was then treated at 210 °C in an oxidizing atmosphere containing 20 vol% oxygen and 80 vol% nitrogen for 3.5 h to obtain an iridium-cobalt nanowire catalyst.

[0080] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 48.3 cm² in a three-electrode system. 2 The catalyst specific activity is 108.3 μA / cm. 2 At 10mA·cm -2 It operated stably for 44 hours at the specified current density.

[0081] Example 7

[0082] 2.75 g of polyvinylpyrrolidone (PVP), 0.25 mmol of tetrairidium dodecylcarbonyl and 8 mmol of nickel chloride hexahydrate were added to 480 g of ethylene glycol and stirred until completely dissolved. Then, 24 mmol of hexadecyltrimethylammonium bromide and 1.2 mmol of potassium iodide were added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 160 °C and 1.2 bar for 48 h. The dried product was centrifuged with acetone to obtain a black precipitate, which was ultrasonically dispersed with ethanol, washed with acetone, and the above steps were repeated several times to obtain purified iridium-nickel nanowires. The ratio of iridium atoms to nickel atoms was 1:2.5. TEM images of the iridium-nickel nanowires are shown below. Figure 1 Similarly, the nanowires exhibit a narrow size distribution and a twinned structure. The nanowire diameter d is 4.3 ± 0.5 nm, and the twin grain size of the nanowires is 4.7 nm.

[0083] The steps for obtaining nitrogen-doped carbon nanotubes are as follows: 1g of carbon oxide nanotubes and 0.2g of urea are thoroughly ground and mixed, heated at 240°C for 1.5h in an oxidizing atmosphere containing 5 vol% oxygen and 95 vol% helium, and then cooled to obtain nitrogen-doped carbon nanotubes.

[0084] 198 mg of iridium-nickel nanowires were dispersed in 50 mL of ethanol, and 85 mg of nitrogen-doped carbon nanotubes were added. The mixture was ultrasonically treated for 24 h, centrifuged to obtain a black precipitate, and dried in an oven at 90 °C for 12 h to obtain a black solid powder. The solid powder was then treated at 200 °C in an oxidizing atmosphere containing 20 vol% oxygen and 80 vol% nitrogen for 1 h to obtain an iridium-nickel nanowire catalyst.

[0085] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 46.0 cm² in a three-electrode system. 2 The catalyst specific activity is 87.5 μA / cm. 2 At 10mA·cm -2 It operated stably for 42 hours at the specified current density.

[0086] Example 8

[0087] 3.5 g of polyvinylpyrrolidone (PVP), 1 mmol of iridium chloride hydrate, and 5 mmol of cobalt acetate were added to 500 g of glycerol and stirred until completely dissolved. Then, 26 mmol of cetyltrimethylammonium bromide and 0.5 mmol of sodium iodide were added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 190 °C and 1.5 bar for 24 h. The resulting product was centrifuged with acetone, and the resulting black precipitate was dispersed ultrasonically with ethanol. The precipitate was then washed with acetone by centrifugation, and the above steps were repeated several times. The purified iridium-cobalt nanowires were obtained by drying. The ratio of iridium atoms to cobalt atoms was 1:1.5. TEM images of the iridium-cobalt nanowires are shown below. Figure 1 Similarly, the nanowires exhibit a narrow size distribution and a twinned structure. The nanowire diameter d is 3.9 ± 0.4 nm, and the twin grain size of the nanowires is 3.7 nm.

[0088] The steps for obtaining nitrogen-doped graphene are as follows: 1g of graphene oxide and 5g of melamine are thoroughly ground and mixed, heated at 220°C for 3 hours in an oxidizing atmosphere containing 5 vol% oxygen and 95 vol% helium, and then cooled to obtain nitrogen-doped graphene.

[0089] 85 mg of iridium-cobalt nanowires were dispersed in 50 mL of ethanol, and 85 mg of nitrogen-doped graphene was added. The mixture was ultrasonically treated for 8 h, centrifuged to obtain a black precipitate, and dried in an oven at 80 °C for 8 h to obtain a black solid powder. The solid powder was then treated at 280 °C in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium for 3 h to obtain an iridium-cobalt nanowire catalyst.

[0090] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 49.8 cm² in a three-electrode system. 2 The catalyst specific activity is 116.5 μA / cm. 2 At 10mA·cm -2 It operated stably for 42 hours at the specified current density.

[0091] Example 9

[0092] 2.5 g of polyvinylpyrrolidone (PVP), 1 mmol of iridium chloride hydrate, and 0.3 mmol of cobalt chloride hexahydrate were added to 475 g of ethylene glycol and stirred until completely dissolved. Then, 12 mmol of tetraethylammonium bromide and 0.5 mmol of potassium iodide were added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 190 °C and 1 bar for 48 h. The resulting product was centrifuged with acetone, and the resulting black precipitate was dispersed ultrasonically with ethanol. The precipitate was then washed with acetone by centrifugation, and the above steps were repeated several times. The purified iridium-cobalt nanowires were obtained by drying. The ratio of iridium atoms to cobalt atoms was 1:0.1. TEM images of the iridium-cobalt nanowires are shown below. Figure 1 Similarly, the nanowires exhibit a narrow size distribution and a twinned structure. The nanowire diameter d is 0.5 ± 0.1 nm, and the twin grain size of the nanowires is 0.4 nm.

[0093] The steps for obtaining nitrogen-doped graphene are as follows: 1g of graphene oxide and 4g of urea are thoroughly ground and mixed, heated at 250°C for 2 hours in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium, and then cooled to obtain nitrogen-doped graphene powder.

[0094] 9.5 mg of iridium-cobalt nanowires were dispersed in 50 mL of ethanol, 85 mg of nitrogen-doped graphene was added, and the mixture was sonicated for 12 h. After centrifugation, a black precipitate was obtained and dried in an oven at 80 °C for 8 h to obtain a black solid powder. The solid powder was then treated at 250 °C in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium for 2.5 h to obtain an iridium-cobalt nanowire catalyst.

[0095] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 77.9 cm² in a three-electrode system. 2 The catalyst specific activity is 71.7 μA / cm. 2 At 10mA·cm -2 It operates stably for 35 hours at the specified current density.

[0096] Example 10

[0097] 2.5 g of polyvinylpyrrolidone (PVP), 1 mmol of iridium chloride hydrate, and 15 mmol of cobalt chloride hexahydrate were added to 475 g of ethylene glycol and stirred until completely dissolved. Then, 12 mmol of tetraethylammonium bromide and 0.5 mmol of potassium iodide were added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 190 °C and 1 bar for 48 h. The resulting product was centrifuged with acetone, and the resulting black precipitate was dispersed ultrasonically with ethanol, washed with acetone by centrifugation, and the above steps were repeated several times. The purified iridium-cobalt nanowires were obtained by drying. The ratio of iridium atoms to cobalt atoms was 1:5. TEM images of the iridium-cobalt nanowires are shown below. Figure 1 Similarly, the nanowires exhibit a narrow size distribution and a twinned structure. The nanowire diameter d is 5.0 ± 0.7 nm, and the twin grain size of the nanowires is 4.4 nm.

[0098] The steps for obtaining nitrogen-doped graphene are as follows: 1g of graphene oxide and 4g of urea are thoroughly ground and mixed, heated at 250°C for 2 hours in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium, and then cooled to obtain nitrogen-doped graphene powder.

[0099] 1.6 g of iridium-cobalt nanowires were dispersed in 50 mL of ethanol, 85 mg of nitrogen-doped graphene was added, and the mixture was sonicated for 12 h. After centrifugation, a black precipitate was obtained and dried in an oven at 80 °C for 8 h to obtain a black solid powder. The solid powder was then treated at 250 °C in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium for 2.5 h to obtain an iridium-cobalt nanowire catalyst.

[0100] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 36.2 cm² in a three-electrode system. 2 The catalyst specific activity is 57.2 μA / cm. 2 At 10mA·cm -2 It operated stably for 27 hours at the specified current density.

[0101] Comparative Example 1

[0102] A commercially available iridium-carbon catalyst with a 40% loading was tested at 25°C with 0.5 mol·L⁻¹ oxygen saturation. -1 In sulfuric acid solution, using a three-electrode system at a reaction overpotential of 0.25 V, the electrochemically active surface area of ​​the catalyst is 28.6 cm². 2 The catalyst specific activity is 36.6 μA / cm. 2 At 10mA·cm -2 It operated stably for 13 hours at the specified current density.

[0103] Comparative Example 2

[0104] 2.5 g of polyvinylpyrrolidone (PVP), 1 mmol of iridium chloride hydrate, and 2 mmol of cobalt chloride hexahydrate were added to 475 g of ethylene glycol and stirred until completely dissolved. Then, 0.5 mmol of potassium iodide was added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 190 °C and 1 bar for 48 h. The resulting product was centrifuged with acetone, and the resulting black precipitate was dispersed ultrasonically with ethanol. The precipitate was then washed with acetone by centrifugation, and the above steps were repeated several times. The purified iridium-cobalt nanowires were obtained by drying. The ratio of iridium atoms to cobalt atoms was 1:0.6. TEM images of the iridium-cobalt nanowires are shown below. Figure 1 Similarly, the nanowires exhibit a narrow size distribution and a twinned structure. The nanowire diameter d is 4.9 ± 0.6 nm, and the twin grain size of the nanowires is 4.1 nm.

[0105] The steps for obtaining nitrogen-doped graphene are as follows: 1g of graphene oxide and 4g of urea are thoroughly ground and mixed, heated at 250°C for 2 hours in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium, and then cooled to obtain nitrogen-doped graphene powder.

[0106] 46 mg of iridium-cobalt nanowires were dispersed in 50 mL of ethanol, 85 mg of nitrogen-doped graphene was added, and the mixture was sonicated for 12 h. After centrifugation, a black precipitate was obtained and dried in an oven at 80 °C for 8 h to obtain a black solid powder. The solid powder was then treated at 250 °C in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium for 2.5 h to obtain an iridium-cobalt nanowire catalyst.

[0107] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 37.7 cm² in a three-electrode system. 2 The catalyst specific activity is 74.9 μA / cm. 2 At 10mA·cm -2 It operated stably for 16 hours at the specified current density.

[0108] Comparative Example 3

[0109] 2.5 g of polyvinylpyrrolidone (PVP), 1 mmol of iridium chloride hydrate, and 2 mmol of cobalt chloride hexahydrate were added to 475 g of ethylene glycol and stirred until completely dissolved. Then, 12 mmol of tetraethylammonium bromide was added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 190 °C and 1 bar for 48 h. The resulting product was centrifuged with acetone, and the resulting black precipitate was dispersed ultrasonically with ethanol. The precipitate was then washed with acetone by centrifugation, and the above steps were repeated several times. The purified iridium-cobalt nanocrystals were obtained by drying. The ratio of iridium atoms to cobalt atoms was 1:0.6. A TEM image of the iridium-cobalt nanocrystals is shown below. Figure 2 As shown, the diameter d of the nanocrystals is 3.5 ± 0.2 nm.

[0110] The steps for obtaining nitrogen-doped graphene are as follows: 1g of graphene oxide and 4g of urea are thoroughly ground and mixed, heated at 250°C for 2 hours in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium, and then cooled to obtain nitrogen-doped graphene powder.

[0111] 46 mg of iridium-cobalt nanocrystals were dispersed in 50 mL of ethanol, 85 mg of nitrogen-doped graphene was added, and the mixture was sonicated for 12 h. After centrifugation, a black precipitate was obtained and dried in an oven at 80 °C for 8 h to obtain a black solid powder. The solid powder was then treated at 250 °C in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium for 2.5 h to obtain an iridium-cobalt nanocrystal catalyst.

[0112] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 53.5 cm² in a three-electrode system. 2 The catalyst specific activity is 47.8 μA / cm. 2 At 10mA·cm -2 It operated stably for 27 hours at the specified current density.

[0113] Comparative Example 4

[0114] 1 mmol of iridium chloride hydrate and 2 mmol of cobalt chloride hexahydrate were added to 475 g of ethylene glycol and stirred until completely dissolved. Then, 12 mmol of tetraethylammonium bromide and 0.5 mmol of potassium iodide were added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 190 °C and 1 bar for 48 h. The product was centrifuged with acetone, and the resulting black precipitate was dispersed by ultrasonication with ethanol, followed by washing with acetone by centrifugation. This process was repeated several times, and the purified iridium-cobalt nanocrystals were obtained by drying. The ratio of iridium atoms to cobalt atoms was 1:0.3. The diameter d of the iridium-cobalt nanocrystals was 243 ± 57 nm.

[0115] The steps for obtaining nitrogen-doped graphene are as follows: 1g of graphene oxide and 4g of urea are thoroughly ground and mixed, heated at 250°C for 2 hours in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium, and then cooled to obtain nitrogen-doped graphene powder.

[0116] 46 mg of iridium-cobalt nanocrystals were dispersed in 50 mL of ethanol, 85 mg of nitrogen-doped graphene was added, and the mixture was sonicated for 12 h. After centrifugation, a black precipitate was obtained and dried in an oven at 80 °C for 8 h to obtain a black solid powder. The solid powder was then treated at 250 °C in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium for 2.5 h to obtain an iridium-cobalt nanocrystal catalyst.

[0117] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 5.9 cm² in a three-electrode system at a reaction overpotential of 0.25 V. 2 The catalyst specific activity is 12.5 μA / cm. 2 At 10mA·cm -2 It operated stably for 12 hours at the specified current density.

[0118] Comparative Example 5

[0119] 2.5 g of polyvinylpyrrolidone (PVP) and 1 mmol of hydrated iridium chloride were added to 475 g of ethylene glycol and stirred until completely dissolved. Then, 12 mmol of tetraethylammonium bromide and 0.5 mmol of potassium iodide were added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 190 °C and 1 bar for 48 h. The resulting product was centrifuged with acetone, and the resulting black precipitate was dispersed ultrasonically with ethanol. The precipitate was then washed with acetone by centrifugation. This process was repeated several times, and the purified iridium nanowires were obtained after drying. TEM images of the iridium nanowires are shown below. Figure 1 Similarly, the nanowires exhibit a narrow size distribution and a twinned structure. The nanowire diameter d is 2.7 ± 0.3 nm, and the twin grain size of the nanowires is 2.6 nm.

[0120] The steps for obtaining nitrogen-doped graphene are as follows: 1g of graphene oxide and 4g of urea are thoroughly ground and mixed, heated at 250°C for 2 hours in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium, and then cooled to obtain nitrogen-doped graphene powder.

[0121] 46 mg of iridium nanowires were dispersed in 50 mL of ethanol, 85 mg of nitrogen-doped graphene was added, and the mixture was sonicated for 12 h. After centrifugation, a black precipitate was obtained and dried in an oven at 80 °C for 8 h to obtain a black solid powder. The solid powder was then treated at 250 °C in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium for 2.5 h to obtain an iridium nanowire catalyst.

[0122] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 58.3 cm² in a three-electrode system at a reaction overpotential of 0.25 V. 2 The catalyst specific activity is 45.1 μA / cm. 2 At 10mA·cm -2 It operated stably for 22 hours at the specified current density.

[0123] Comparative Example 6

[0124] 2.5 g of polyvinylpyrrolidone (PVP), 1 mmol of iridium chloride hydrate, and 2 mmol of cobalt chloride hexahydrate were added to 475 g of ethylene glycol and stirred until completely dissolved. Then, 12 mmol of tetraethylammonium bromide and 0.5 mmol of potassium iodide were added, and the mixture was stirred for 0.5 h to obtain a clear solution. This solution was added to an 800 mL hydrothermal reactor and reacted at 190 °C and 1 bar for 48 h. The resulting product was centrifuged with acetone, and the resulting black precipitate was dispersed ultrasonically with ethanol. The precipitate was then washed with acetone by centrifugation, and the above steps were repeated several times. The purified iridium-cobalt nanowires were obtained by drying. The ratio of iridium atoms to cobalt atoms was 1:0.6. TEM images of the iridium-cobalt nanowires are shown below. Figure 1 Similarly, the nanowires exhibit a narrow size distribution and a twinned structure. The nanowire diameter d is 3.5 ± 0.3 nm, and the twin grain size of the nanowires is 3.4 nm.

[0125] 46 mg of iridium-cobalt nanowires were dispersed in 50 mL of ethanol, 85 mg of graphene was added, and the mixture was sonicated for 12 h. After centrifugation, a black precipitate was obtained and dried in an oven at 80 °C for 8 h to obtain a black solid powder. The solid powder was then treated at 250 °C in an oxidizing atmosphere containing 10 vol% oxygen and 90 vol% helium for 2.5 h to obtain an iridium-cobalt nanowire catalyst.

[0126] At 25℃, oxygen saturation is 0.5 mol·L⁻¹ -1 In a sulfuric acid solution, using an Ag / AgCl electrode as the reference electrode, a platinum sheet electrode as the counter electrode, and a rotating disk electrode at 1600 rpm as the working electrode, the electrochemically active surface area of ​​the catalyst is 53.6 cm² in a three-electrode system. 2The catalyst specific activity is 48.4 μA / cm. 2 At 10mA·cm -2 It operated stably for 18 hours at the specified current density.

[0127] Table 1. Physicochemical properties and catalytic performance of each embodiment and comparative example.

[0128]

[0129] The embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the terms used herein are descriptive and explanatory, not limiting. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from its scope and spirit. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications having the same function.

Claims

1. An iridium-based catalyst, said catalyst comprising an active component and a support; in, The active component includes iridium and at least one transition metal selected from iron, cobalt, and nickel; the support is a nitrogen-doped carbon material. The active component is twinned nanowires; the diameter of the nanowires is... d The nanowires have a diameter of 0.5–5 nm, and the twin grain size is (0.8–1.1) nm. d nm; The atomic ratio of iridium to transition metal in the active component is 1:(0.1~5). The catalyst has an electrochemical surface area of ​​36-78 cm². 2 .

2. The iridium-based catalyst according to claim 1, characterized in that, The catalyst comprises 10-95 parts by weight of active component and 5-90 parts by weight of nitrogen-doped carbon material support.

3. The iridium-based catalyst according to claim 1, characterized in that, The nitrogen-doped carbon material is selected from at least one of nitrogen-doped carbon black, nitrogen-doped graphene, and nitrogen-doped carbon nanotubes.

4. The iridium-based catalyst according to claim 1, characterized in that, The nitrogen-doped carbon material has a nitrogen molar content of 0.5% to 5%.

5. A method for preparing the iridium-based catalyst according to any one of claims 1-4, comprising the following steps: (1) Iridium source and transition metal source, surfactant, crystal plane coordination agent and organic alcohol are mixed and heated to react to obtain iridium-based nanowire active components; (2) The nitrogen-doped carbon material is mixed with the iridium-based nanowire active component and then subjected to atmospheric heat treatment to obtain the iridium-based catalyst.

6. The preparation method according to claim 5, characterized in that, The iridium source mentioned in step (1) is selected from at least one of iridium chloride, iridium acetylacetonate, iridium carbonyl, hexachloroiridic acid, sodium hexachloroiridate, and ammonium hexachloroiridate.

7. The preparation method according to claim 5, characterized in that, The transition metal source mentioned in step (1) is selected from at least one of the soluble chlorides, bromides, nitrates, sulfates, carbonates, acetates, and acetylacetone salts corresponding to the transition metals iron, cobalt, and nickel.

8. The preparation method according to claim 5, characterized in that, The surfactant mentioned in step (1) is polyvinylpyrrolidone.

9. The preparation method according to claim 5, characterized in that, The crystal plane coordination reagent mentioned in step (1) is a quaternary ammonium salt containing bromide ions and an inorganic iodide.

10. The preparation method according to claim 5, characterized in that, The organic alcohol mentioned in step (1) is a polyol.

11. The preparation method according to claim 5, characterized in that, The molar ratio of the iridium source, transition metal source, and crystal plane coordination reagent mentioned in step (1) is 1:(0.5~15):(5.1~32).

12. The preparation method according to claim 5, characterized in that, The molar ratio of the iridium source, transition metal source, and crystal plane coordination reagent mentioned in step (1) is 1:(0.5~10):(5.1~32).

13. The preparation method according to claim 9, characterized in that, The molar ratio of the iridium source, the bromide-containing quaternary ammonium salt of the crystal plane coordination reagent, and the inorganic iodide of the crystal plane coordination reagent in step (1) is 1:(5~30):(0.1~1.2).

14. The preparation method according to claim 5, characterized in that, The iridium source mentioned in step (1) is based on hydrated iridium chloride and the mass ratio of surfactant to organic alcohol is 1:(8~12):(1500~1800).

15. The preparation method according to claim 5, characterized in that, The heating temperature in step (1) is 130~230℃; the time is 4~60h; and the pressure is 0.8~1.5bar.

16. The preparation method according to claim 5, characterized in that, In step (2), the carbon support in the nitrogen-doped carbon material is at least one of carbon black, graphene, carbon nanotubes, and activated carbon.

17. The preparation method according to claim 5, characterized in that, In step (2), the mass ratio of the iridium-based nanowire active component to the nitrogen-doped carbon support is 10~95:5~90.

18. The preparation method according to claim 5, characterized in that, The atmosphere heat treatment in step (2) is to treat in an oxidizing atmosphere at 200~350°C for 0.5~4h.

19. The preparation method according to claim 18, characterized in that, The oxygen content in the oxidizing atmosphere described in step (2) is 5 vol% to 20 vol% oxygen.

20. The use of the iridium-based catalyst according to any one of claims 1-4 in the oxygen evolution reaction under acidic conditions.

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