A method for preparing a hydrogen fuel cell catalyst and the catalyst prepared therefrom

Abstract

This invention discloses a method for preparing a hydrogen fuel cell catalyst and the catalyst prepared therefrom. The method includes: S1, mixing crushed carbon black, polyvinylpyrrolidone, and nitric acid solution, heating and refluxing with stirring, rinsing the carbon black, and then drying and crushing the carbon black to obtain a spare carbon support; S2, dissolving platinum precursor powder and additives in a mixed solution of deionized water and organic liquid, and stirring the mixture to obtain a platinum precursor solution; S3, placing the spare carbon support in a feed cylinder, spraying the platinum precursor solution into the feed cylinder and continuously dispersing and stirring, then pressurizing and then evaporating the solvent to obtain a sample; S4, rapidly cooling the sample with liquid nitrogen and freeze-drying it in a freeze dryer to obtain a lyophilized powder; S5, heat-treating the lyophilized powder in a reducing mixed gas to obtain the catalyst. This invention has a simple production process, is easy to implement, provides controllable product characteristics, and can improve the activity and stability of the prepared platinum-carbon catalyst.

Description

Technical Field

[0001] This invention relates to battery catalysts, specifically a method for preparing a hydrogen fuel cell catalyst and the catalyst prepared therefrom. Background Technology

[0002] Currently, most catalysts used in hydrogen fuel cells are platinum-carbon catalysts (Pt / C). The key physical properties of platinum-carbon catalysts (such as platinum particle size distribution, morphology, dispersion on the support, physical properties of the carbon support, and surface chemical properties) significantly affect their activity and stability. These key properties are closely related to their preparation methods. Common existing methods for preparing platinum-carbon catalysts include organic solvothermal methods, microemulsion methods, and colloidal methods. These methods suffer from drawbacks such as high production costs, complex process control, difficulty in removing impurities and / or surfactants, and the use of large amounts of organic reagents, making large-scale deployment difficult. Platinum-carbon catalysts prepared using existing methods exhibit low activity and stability, further hindering the commercial application of fuel cells. Therefore, ensuring the controllability of the key physical properties of platinum-carbon catalysts to improve their activity and stability has become a widely concerned issue. However, no corresponding technologies or related reports have been found to date. Summary of the Invention

[0003] The purpose of this invention is to address the problem that existing platinum-carbon catalysts for hydrogen fuel cells suffer from low activity and stability due to limitations in their preparation methods. This invention provides a method for preparing a hydrogen fuel cell catalyst that is simple to implement, easy to achieve, and produces controllable product characteristics, while improving the activity and stability of the prepared platinum-carbon catalyst. This invention also discloses the catalyst prepared by the above-mentioned method for preparing a hydrogen fuel cell catalyst.

[0004] The objective of this invention is mainly achieved through the following technical solutions:

[0005] A method for preparing a hydrogen fuel cell catalyst includes the following steps:

[0006] Step S1: Mix crushed carbon black, polyvinylpyrrolidone, and a 0.5–5 M nitric acid solution, heat to 60–120 °C and reflux and stir for 3–12 h, then rinse the carbon black with deionized water until the filtrate is neutral, and then dry the rinsed carbon black in a vacuum environment at a drying temperature of 100–200 °C for 6–12 h to obtain pretreated conductive carbon black. Finally, crush the pretreated conductive carbon black to obtain a ready-made carbon carrier; wherein, when mixing carbon black, polyvinylpyrrolidone, and nitric acid solution, the mass ratio of carbon black to polyvinylpyrrolidone is 10–30:1, and the mass ratio of carbon black to nitric acid solution is 1:30–100;

[0007] Step S2: Dissolve platinum precursor powder and additives in a mixed solution of deionized water and organic liquid. Stir the mixture at 80-100℃ and with an ultrasonic power of not less than 2KW for 0.5-1h to obtain a platinum precursor solution. The mass ratio of deionized water to organic liquid is 1:1-20, the mass ratio of platinum precursor powder to mixed solution is 1:20-200, and the mass ratio of additives to mixed solution is 1:100-500.

[0008] Step S3: Place the spare carbon carrier in the barrel, close the barrel and evacuate it to maintain a vacuum level of no more than 200 Pa. Spray the platinum precursor solution into the barrel. During spraying, maintain the barrel at a constant temperature of 20-25°C and continuously disperse and stir the material in the barrel at a dispersion rate of 500-2000 rpm for 10-60 min. After dispersion and stirring, stop evacuating the vacuum and introduce nitrogen into the barrel to pressurize the material at a pressure of 0.1-0.5 MPa for 5-20 min. After pressurization, the barrel is evacuated again to maintain a vacuum level not exceeding 200 Pa and the barrel is kept at a constant temperature of 100°C for solvent evaporation for 1–2 hours. The mass ratio of platinum to carbon support in the platinum precursor solution is 1:0.5–4. The platinum precursor solution is divided into at least three portions. One portion of the platinum precursor solution is sprayed during each spraying cycle. After the above dispersion, stirring, pressurization, and solvent evaporation steps are completed, another portion of the platinum precursor solution is sprayed. The above steps are repeated until all platinum precursor solutions are sprayed to obtain the sample.

[0009] Step S4: The sample obtained in step S3 is rapidly cooled with liquid nitrogen and then freeze-dried in a freeze dryer for 8-24 hours to obtain freeze-dried powder.

[0010] Step S5: Heat-treat the freeze-dried powder in a reducing mixed gas at a temperature of 400-900℃ for 1-3 hours to obtain the catalyst; wherein the reducing mixed gas includes 5-10 vol% of reducing gas ammonia, and the remainder is argon or nitrogen.

[0011] In step S1 of this invention, crushed carbon black, polyvinylpyrrolidone, and nitric acid solution are mixed and refluxed under heating with stirring. After treatment, excess nitric acid is removed by rinsing with deionized water until the filtrate is neutral. The carbon black filter cake is then vacuum dried. During vacuum drying, a vacuum pump is used to maintain a vacuum environment and the pump is continuously operated to obtain pretreated conductive carbon black. Finally, the pretreated conductive carbon black is crushed using a crusher to obtain a usable carbon support. Step S1 of this invention is a carbon support pretreatment step. The purpose of carbon support pretreatment is to introduce uniformly distributed oxygen-containing groups such as carboxyl groups and phenolic hydroxyl groups (oxygen-containing groups such as carboxyl groups and phenolic hydroxyl groups are formed on the surface of carbon black under the oxidation of nitric acid) in a controllable manner. This facilitates the substitution reaction between the nitrogen source and carboxyl groups and phenolic hydroxyl groups in the later step S5 to achieve nitrogen functionalization of the carbon support. In addition, oxygen-containing groups can serve as adsorption and precipitation sites for platinum salts, which is beneficial to promoting the uniform distribution of platinum salts on the surface of the carbon support. In step S1 of this invention, the carbon support pretreatment stage uses nitric acid treatment. Nitric acid treatment increases the number of defects on the carbon material surface and may even damage the structure. Polyvinylpyrrolidone can act as a dispersant for carbon materials in solution, which helps the carbon support to undergo uniform oxidation treatment. The polyvinylpyrrolidone adsorbed on the carbon material surface can act as a defect repair agent for carbon materials in the subsequent heat treatment process, reducing easily corroded sites on the carbon material surface and effectively improving the service life of the carbon support, thereby enhancing the service life of the catalyst.

[0012] In step S2 of this invention, platinum precursor powder and additives are dissolved in a mixed solution of deionized water and organic liquid in a glass reactor. The additives primarily improve the stability and dispersibility of the platinum salt in the solution, regulate the fluidity of the platinum salt on the carbon support surface, and promote uniform coverage of the platinum salt on the carbon support surface. The ratio of deionized water to organic liquid is mainly to adjust the solubility of the platinum salt in the mixed solution, so that the platinum salt is in a near-saturated state, facilitating rapid precipitation of the platinum salt during subsequent solution evaporation to form growth sites for platinum nanoparticles. In specific implementation of step S2 of this invention, the higher the ultrasonic power, the better the dispersion effect; a value of 2KW ensures sufficient ultrasonic power to guarantee adequate ultrasonic dispersion.

[0013] In step S3 of this invention, the material is fed into a double-layered cylinder of a double planetary mixer. A vacuum environment in the cylinder is maintained by a vacuum pump. The platinum precursor solution is sprayed into the cylinder through a spray nozzle. During the spraying of the platinum precursor solution, the dispersion and stirring systems of the double planetary mixer are turned on to continuously disperse and stir the material, and the circulating refrigeration unit is turned on to cool the cylinder and keep it at a constant temperature. After dispersion and stirring, the vacuum pump and valve are turned off, and nitrogen is introduced into the cylinder through the nitrogen valve to pressurize the material. After the pressurization is completed, the vacuum pump is turned on to evaporate the solvent. During the solvent evaporation, the valve of the circulating refrigeration unit is turned off, and the circulating heater is turned on to heat the cylinder at a constant temperature of 100°C. In step S3 of this invention, the repeated spraying, vacuuming, stirring / dispersing, and nitrogen pressurization of the platinum salt precursor solution all aim to force the platinum salt to mix as uniformly as possible with the carbon support and to penetrate into the pores of the carbon support. The vacuum-nitrogen pressurization process effectively removes oxygen and solvent from the pores of the carbon support, preventing the oxidation of platinum nanoparticles generated during subsequent thermal reduction and thus avoiding an increase in the content of oxidized platinum. Vacuuming lowers the solvent boiling point and aids in solvent evaporation. In step S3, when maintaining a constant temperature of 100°C for solvent evaporation, heating is stopped after 1-2 hours, once the solvent is no longer visible to the naked eye.

[0014] The freeze-drying process in step S4 of this invention is characterized by in-situ freeze-drying of the material. The dried material retains its original chemical composition and physical properties, avoiding the platinum salt decomposition that occurs with other heating-type drying methods. Secondly, the freeze-dried material presents as a loose powder, which facilitates sufficient contact and reaction with the reactant gases during subsequent thermal reduction, thus improving the consistency of the catalyst product. In step S4, the sample is placed in a freeze dryer for freeze-drying. The high vacuum environment (<10 Pa) of the freeze dryer promotes the removal of oxygen and solvent from the pores of the carbon support, preventing the oxidation of platinum nanoparticles generated during subsequent thermal reduction and thus preventing an increase in the content of oxidized platinum.

[0015] In specific implementation of step S5 of this invention, the freeze-dried powder is placed in a rotary tube furnace. The main purpose of using a rotary tube furnace is to reduce the uneven heating of the material. At the same time, the rotation of the furnace tube causes the material to tumble, which is conducive to the full contact and reaction between the material and the reacting gas, and can improve the consistency of the catalyst product. In step S5 of this invention, heat treatment is carried out in an ammonia-containing atmosphere for three reasons: first, to reduce platinum salt to elemental platinum; second, to ensure that the oxygen-containing functional groups on the surface of the catalyst are minimized, thereby increasing the zero-valent platinum content in the catalyst; and third, ammonia can react with the oxygen-containing functional groups on the surface of the carbon support to achieve the grafting of nitrogen-containing groups on the surface of the carbon support.

[0016] Furthermore, in step S1, the carbon black added when mixing carbon black, polyvinylpyrrolidone, and nitric acid solution has a specific surface area of ​​400–1200 m². 2 / g, the added carbon black is mechanically crushed and passed through a 400-mesh sieve, and the graphite crystallite size of the carbon black is 2-5nm. In step S1 of this invention, when mixing the crushed carbon black, polyvinylpyrrolidone, and nitric acid solution, if the specific surface area of ​​the carbon black is less than 400m², 2 / g, which is not conducive to the dispersion and loading of platinum particles; if the specific surface area of ​​carbon black is higher than 1200m², it is also unfavorable. 2 If the specific surface area of ​​carbon black is reduced to a certain value (e.g.), its stability will decrease. This invention limits the specific surface area of ​​carbon black to 400–1200 m². 2 The sieving method, while ensuring carbon black stability, also facilitates the dispersion and loading of platinum particles. Graphite crystallites are the graphite crystals on the surface / interior of carbon black. Larger crystallite sizes result in better surface carbon black stability; however, excessively large crystallite sizes indicate excessive graphitization of the carbon black, which is detrimental to the loading and dispersion of platinum particles. This invention limits the graphite crystallite size to 2–5 nm, further ensuring carbon black stability while facilitating the dispersion and loading of platinum particles. The advantage of sieving in this invention is that it avoids large carbon black agglomerates. The crushed carbon black has a larger contact area with the nitric acid solution, thus achieving sufficient surface oxidation treatment.

[0017] Furthermore, the molecular weight of the polyvinylpyrrolidone is no higher than 40,000. High molecular weight polyvinylpyrrolidone has too much viscosity, which is not conducive to the dispersion of carbon support. Therefore, this invention limits the molecular weight of polyvinylpyrrolidone to no higher than 40,000, that is, using low molecular weight polyvinylpyrrolidone, which is more conducive to the dispersion of carbon support.

[0018] Furthermore, the platinum precursor powder is any one or a combination of two or more of the following: tetraammineplatinum dibicarbonate, tetraammineplatinum oxalate, tetraammineplatinum hydrogen phosphate, tetraammineplatinum acetate, tetraammineplatinum sulfate, tetraammineplatinum nitrate, diammineplatinum dinitroso, tetraammineplatinum dichloro, ammonium chloroplatinate, and tetraammineplatinum dihydroxoxide.

[0019] Furthermore, the additive is any one of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, fatty acyl alkanolamine polyoxyethylene ether, and octylphenol polyoxyethylene ether.

[0020] Furthermore, the organic liquid is any one or a combination of two or more of isopropanol, n-propanol, glycerol, acetic acid, and trichloroacetaldehyde.

[0021] A hydrogen fuel cell catalyst prepared using the above-described method for preparing a hydrogen fuel cell catalyst.

[0022] In summary, compared with the prior art, the present invention has the following beneficial effects: It addresses the drawbacks of traditional preparation systems, such as strong adsorption of chloride ions, difficult-to-remove organic matter, poor size distribution of platinum nanoparticles (excessively large or small platinum nanoparticles easily lead to low catalyst activity or poor stability), poor dispersion of platinum nanoparticles (a large number of platinum particle agglomerates easily lead to low platinum utilization and poor activity), and undesirable positions of platinum nanoparticles (e.g., mainly existing on the surface of the carbon support, easily poisoned by ionomers, resulting in low catalyst activity; in actual operation, platinum nanoparticles are easily dissolved, migrated, agglomerated, and detached, leading to a significant decrease in catalyst performance). By improving the process steps and material usage, the present invention can improve the stability of the platinum precursor solution and its immersion efficiency and effect in porous carbon supports, enhance the compatibility of the carbon support, and thus effectively control the physicochemical properties of the catalyst (such as the particle size distribution of platinum nanoparticles, the location and proportion of platinum nanoparticles, the content and distribution of nitrogen, and the number of defects on the surface of the carbon material). Thus, the present invention can improve the shortcomings of existing processes in preparing platinum-carbon catalysts, such as low utilization rate of active components, poor stability, and poor distribution of ionomers, while also avoiding the negative corrosive effect of oxidizing solutions on carbon supports. Attached Figure Description

[0023] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0024] Figure 1 TEM image of the catalyst in Example 1;

[0025] Figure 2 TEM image of the catalyst in Comparative Example 1;

[0026] Figure 3 This is a TEM image of the catalyst in Comparative Example 2;

[0027] Figure 4 The image shows a TEM image of the catalyst in Comparative Example 3.

[0028] Figure 5 The fresh membrane electrode IV test curves of the catalysts of Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3 are shown.

[0029] Figure 6 The membrane electrode assembly (MEA) cycle IV test curves of the catalysts of Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3 are shown.

[0030] Figure 7 The IV test curves of the catalysts in Example 1 and Comparative Example 4 before and after membrane electrode cycling are shown.

[0031] Figure 8This is a TEM image of the membrane electrode assembly of the catalyst in Example 1 after cycling;

[0032] Figure 9 This is a TEM image of the membrane electrode of the catalyst in Comparative Example 2 after cycling.

[0033] Figure 10 This is a TEM image of the membrane electrode after cycling of the catalyst in Comparative Example 3.

[0034] Figure 11 The XRD patterns of the catalysts in Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3 are shown below.

[0035] Figure 12 The XRD patterns of the catalyst layers after membrane electrode cycling of the catalysts of Example 1, Comparative Example 2 and Comparative Example 3 are shown.

[0036] Figure 13 The nitrogen content test charts are for the catalysts of Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3.

[0037] Figure 14 The graph shows the corrosion sensitivity test results of carbon support in Comparative Example 5. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0039] Example 1:

[0040] KETJEN Black EC300J superconducting carbon black (KB300) from Lion Corporation of Japan was mechanically crushed and passed through a 400-mesh sieve for later use. 10g of the crushed carbon black, 0.5g of polyvinylpyrrolidone, and 600g of 2M nitric acid solution were weighed, mixed, and stirred. The mixture was then refluxed at 80℃ for 8 hours. After reflux, the carbon black was rinsed with deionized water until the filtrate was neutral. The rinsed carbon black sample was placed in a vacuum drying oven and vacuum dried at 120℃ for 8 hours. After vacuum drying, the carbon black sample was crushed again to obtain the carbon carrier for later use. The carbon black used in the mixing process had a specific surface area of ​​800 m². 2 / g, the graphite crystallite size of carbon black is 2-5nm, and the molecular weight of polyvinylpyrrolidone is 10000.

[0041] Take 15.63g of tetraammineplatinum acetate, 1305g of mixed solution (305g of deionized water and 1000g of acetic acid in the mixed solution), and 3.26g of alkylphenol polyoxyethylene ether and put them into a glass reactor. At the same time, the materials are stirred and sonicated for 60 minutes with an ultrasonic power of 3KW and a temperature of 90℃.

[0042] Eightg of crushed carbon carrier was placed in the double-jacketed hopper of a dual planetary mixer. After closing the hopper, a vacuum pump was turned on to create a vacuum. Tetraammineplatinum acetate solution was sprayed into the hopper through a spray nozzle. During the spraying of the tetraammineplatinum acetate solution, the dispersion and stirring systems of the dual planetary mixer were continuously activated to disperse and stir the material. After dispersion and stirring, the vacuum pump and valves were closed, and nitrogen was introduced through the nitrogen valve to pressurize the material. After pressurization, the vacuum pump was turned on to evaporate the solvent, and the hopper temperature was kept constant at 100°C. In this embodiment, the tetraammineplatinum acetate solution was divided into three portions. One portion of platinum precursor solution was sprayed during each spraying cycle. After the above dispersion, stirring, pressurization, and solvent evaporation steps were completed, another portion of platinum precursor solution was sprayed. This process was repeated until all three portions of platinum precursor solution were sprayed to obtain the sample. During dispersion and stirring, a circulating refrigeration unit was turned on to cool the hopper, keeping it at a constant temperature of 20°C. The dispersion and stirring time was 60 minutes, and the dispersion rate was 1000 rpm. During solvent evaporation, first close the valve of the circulating refrigeration unit, and at the same time turn on the circulating heater to heat the barrel at a constant temperature of 100°C for 1 hour; when evacuating, the vacuum degree is 80 Pa; the pressurization pressure is 0.5 MPa and the pressurization time is 10 minutes.

[0043] The sample was rapidly cooled with liquid nitrogen and then freeze-dried in a freeze dryer to obtain freeze-dried powder. The freeze-drying time was 12 hours.

[0044] The freeze-dried powder was placed in a rotary tube furnace and heat-treated in a reducing gas mixture at 600°C for 2 hours at a heating rate of 5°C / min. The reducing gas mixture consisted of 5 vol% ammonia and the remainder argon. After heat treatment, the desired catalyst, labeled PtC-1, with a platinum loading of 50 wt%, was obtained.

[0045] Example 2:

[0046] KETJEN Black EC300J superconducting carbon black (KB300) from Lion Corporation of Japan was mechanically crushed and passed through a 400-mesh sieve for later use. 10g of the crushed carbon black, 1g of polyvinylpyrrolidone, and 1000g of 2M nitric acid solution were weighed, mixed, and stirred. The mixture was then refluxed at 100℃ for 6 hours. After reflux, the carbon black was rinsed until the filtrate was neutral. The rinsed carbon black sample was placed in a vacuum drying oven and vacuum dried at 120℃ for 8 hours. After vacuum drying, the carbon black sample was further crushed to obtain the carbon carrier for later use. The carbon black used in the mixing process had a specific surface area of ​​800 m². 2 / g, the graphite crystallite size of carbon black is 2-5nm, and the molecular weight of polyvinylpyrrolidone is not higher than 8000.

[0047] Take 15.63g of tetraammineplatinum acetate, 2000g of mixed solution (800g of water and 1200g of isopropanol), and 5g of octylphenol polyoxyethylene ether and put them into a glass kettle. At the same time, the materials are stirred and sonicated for 30 minutes with a sonication power of 3KW and a mixture temperature of 90℃.

[0048] Eightg of crushed carbon carrier was placed in the double-jacketed hopper of a dual planetary mixer. After closing the hopper, a vacuum pump was turned on to create a vacuum. Tetraammineplatinum acetate solution was sprayed into the hopper through a spray nozzle. During the spraying of the tetraammineplatinum acetate solution, the dispersion and stirring systems of the dual planetary mixer were continuously activated to disperse and stir the material. After dispersion and stirring, the vacuum pump and valves were closed, and nitrogen was introduced through the nitrogen valve to pressurize the material. After pressurization, the vacuum pump was turned on to evaporate the solvent, and the hopper temperature was kept constant at 100°C. In this embodiment, the tetraammineplatinum acetate solution was divided into four portions. One portion of platinum precursor solution was sprayed during each spraying cycle. After the above dispersion, stirring, pressurization, and solvent evaporation steps were completed, another portion of platinum precursor solution was sprayed. This process was repeated until all four portions of platinum precursor solution were sprayed to obtain the sample. During dispersion and stirring, a circulating refrigeration unit was turned on to cool the hopper, keeping it at a constant temperature of 20°C. The dispersion and stirring time was 60 minutes, and the dispersion rate was 1000 rpm. During solvent evaporation, first close the valve of the circulating refrigeration unit, and at the same time turn on the circulating heater to heat the barrel at a constant temperature of 100°C for 2 hours; when evacuating, the vacuum degree is 40 Pa; the pressurization pressure is 0.2 MPa and the pressurization time is 20 minutes.

[0049] The sample was rapidly cooled with liquid nitrogen and then freeze-dried in a freeze dryer for 16 hours.

[0050] The freeze-dried powder was placed in a rotary tube furnace and heat-treated in a reducing gas mixture at 800°C for 1 hour at a heating rate of 5°C / min. The reducing gas mixture consisted of 10 vol% ammonia and the remainder argon. After heat treatment, the desired catalyst, labeled Pt / C-2, with a platinum loading of 50 wt%, was obtained.

[0051] Example 3:

[0052] KETJEN Black EC300J superconducting carbon black (KB300) from Lion Corporation of Japan was mechanically crushed and passed through a 400-mesh sieve for later use. 10g of the crushed carbon black, 0.4g of polyvinylpyrrolidone, and 800g of 2M nitric acid solution were weighed, mixed, and stirred. The mixture was then refluxed at 60℃ for 12 hours. After reflux, the carbon black was rinsed until the filtrate was neutral. The rinsed carbon black sample was placed in a vacuum drying oven and vacuum dried at 120℃ for 8 hours. After vacuum drying, the carbon black sample was further crushed to obtain the carbon carrier for later use. The carbon black used in the mixing process had a specific surface area of ​​800 m². 2 / g, the graphite crystallite size of carbon black is 2-5nm, and the molecular weight of polyvinylpyrrolidone is 10000.

[0053] Take 15.63g of tetraammineplatinum acetate, 1000g of mixed solution (500g of water and 500g of n-propanol), and 3.5g of fatty alcohol polyoxyethylene ether and put them into a glass kettle. At the same time, the materials are stirred and sonicated for 60 minutes with an ultrasonic power of 3KW and a mixture temperature of 90℃.

[0054] Eightg of crushed carbon carrier was placed in the double-jacketed hopper of a dual planetary mixer. After closing the hopper, a vacuum pump was turned on to create a vacuum. Tetraammineplatinum acetate solution was sprayed into the hopper through a spray nozzle. During the spraying of the tetraammineplatinum acetate solution, the dispersion and stirring systems of the dual planetary mixer were continuously activated to disperse and stir the material. After dispersion and stirring, the vacuum pump and valves were closed, and nitrogen was introduced through the nitrogen valve to pressurize the material. After pressurization, the vacuum pump was turned on to evaporate the solvent, and the hopper temperature was kept constant at 100°C. In this embodiment, the tetraammineplatinum acetate solution was divided into three portions. One portion of platinum precursor solution was sprayed during each spraying cycle. After the above dispersion, stirring, pressurization, and solvent evaporation steps were completed, another portion of platinum precursor solution was sprayed. This process was repeated until all three portions of platinum precursor solution were sprayed to obtain the sample. During dispersion and stirring, a circulating refrigeration unit was turned on to cool the hopper, keeping it at a constant temperature of 20°C. The dispersion and stirring time was 60 minutes, and the dispersion rate was 1000 rpm. During solvent evaporation, first close the valve of the circulating refrigeration unit, and at the same time turn on the circulating heater to heat the barrel at a constant temperature of 100°C for 1 hour; when evacuating, the vacuum degree is 200 Pa; the pressurization pressure is 0.5 MPa and the pressurization time is 20 minutes.

[0055] The samples were rapidly cooled with liquid nitrogen and then freeze-dried in a freeze dryer for 24 hours.

[0056] The freeze-dried powder was placed in a rotary tube furnace and heat-treated in a reducing gas mixture at 400°C for 2 hours at a heating rate of 5°C / min. The reducing gas mixture consisted of 5 vol% ammonia and the remainder argon. After heat treatment, the desired catalyst, labeled Pt / C-3, with a platinum loading of 50 wt%, was obtained.

[0057] Example 4:

[0058] KETJEN Black EC300J superconducting carbon black (KB300) from Lion Corporation of Japan was mechanically crushed and passed through a 400-mesh sieve for later use. 10g of the crushed carbon black, 0.8g of polyvinylpyrrolidone, and 600g of 2M nitric acid solution were weighed, mixed, and stirred. The mixture was then refluxed at 80℃ for 12 hours. After reflux, the carbon black was rinsed until the filtrate was neutral. The rinsed carbon black sample was placed in a vacuum drying oven and vacuum dried at 120℃ for 8 hours. After vacuum drying, the carbon black sample was further crushed to obtain the carbon carrier for later use. The carbon black used in the mixing process had a specific surface area of ​​800 m². 2 / g, the graphite crystallite size of carbon black is 2-5nm, and the molecular weight of polyvinylpyrrolidone is 24000.

[0059] Take 14.41g of tetraammineplatinum oxalate, 1000g of mixed solution (500g of water and 500g of isopropanol), and 3.3g of fatty acyl alcoholamine polyoxyethylene ether and put them into a glass kettle. At the same time, the materials are stirred and sonicated for 45 minutes, with an ultrasonic power of 3KW and a mixture temperature of 90℃.

[0060] Eightg of crushed carbon carrier was placed in the double-jacketed hopper of a dual planetary mixer. After closing the hopper, a vacuum pump was turned on to create a vacuum. Tetraammineplatinum oxalate solution was sprayed into the hopper through a spray nozzle. During the spraying of the tetraammineplatinum oxalate solution, the dispersion and stirring systems of the dual planetary mixer were continuously activated to disperse and stir the material. After dispersion and stirring, the vacuum pump and valves were closed, and nitrogen was introduced through the nitrogen valve to pressurize the material. After pressurization, the vacuum pump was turned on to evaporate the solvent, and the hopper temperature was kept constant at 100°C. In this embodiment, the mass ratio of platinum to the spare carbon carrier in the tetraammineplatinum oxalate solution was 1:1. The tetraammineplatinum oxalate solution was divided into five portions. One portion of the platinum precursor solution was sprayed during each spraying. After the above dispersion, stirring, pressurization, and solvent evaporation steps were completed, another portion of the platinum precursor solution was sprayed. This process was repeated until all five portions of the platinum precursor solution were sprayed to obtain the sample. During dispersion and mixing, the circulating refrigeration unit was turned on to cool the barrel, maintaining it at a constant temperature of 20°C. The dispersion and mixing time was 60 minutes, and the dispersion rate was 1000 rpm. During solvent evaporation, the circulating refrigeration unit valve was first closed, and the circulating heater was turned on to heat the barrel at a constant temperature of 100°C for 1 hour. During vacuuming, the vacuum degree was 100 Pa; the pressurization pressure was 0.4 MPa, and the pressurization time was 15 minutes.

[0061] The samples were rapidly cooled with liquid nitrogen and then freeze-dried in a freeze dryer for 24 hours.

[0062] The freeze-dried powder was placed in a rotary tube furnace and heat-treated in a reducing gas mixture at 700°C for 1 hour at a heating rate of 5°C / min. The reducing gas mixture consisted of 5 vol% ammonia and the remainder argon. After heat treatment, the desired catalyst, labeled Pt / C-4, with a platinum loading of 50 wt%, was obtained.

[0063] Comparative Example 1:

[0064] Lion KB300 superconducting carbon black from Japan was mechanically crushed and passed through a 400-mesh sieve for later use. 10g of the crushed carbon black, 0.5g of polyvinylpyrrolidone, and 600g of 2M nitric acid solution were weighed, mixed, and stirred under reflux at 80℃ for 8 hours. After reflux, the carbon black was rinsed with deionized water until the filtrate was neutral. The rinsed carbon black sample was placed in a vacuum drying oven and vacuum dried at 120℃ for 8 hours. After vacuum drying, the carbon black sample was crushed again to obtain the carbon carrier for later use. The carbon black used in the mixing process had a specific surface area of ​​800 m². 2 / g, polyvinylpyrrolidone molecular weight 10000.

[0065] Take 15.63g of tetraammineplatinum acetate, 1305g of mixed solution (305g of deionized water and 1000g of acetic acid in the mixed solution), and 3.26g of alkylphenol polyoxyethylene ether and put them into a glass kettle. At the same time, the materials are stirred and sonicated for 60 minutes, with an ultrasonic power of 3KW and a temperature of 90℃.

[0066] 8g of crushed carbon carrier was placed in the double-jacketed hopper of a double planetary mixer. After closing the hopper, a vacuum pump was turned on to create a vacuum. Tetraammineplatinum acetate solution was sprayed into the hopper through a spray nozzle. After spraying the tetraammineplatinum acetate solution, the vacuum pump and valves were closed, and nitrogen was introduced through the nitrogen valve to pressurize the material. After pressurization, the vacuum pump was turned on to evaporate the solvent, and the hopper temperature was kept constant at 100°C. In this embodiment, the mass ratio of platinum to spare carbon carrier in the tetraammineplatinum acetate solution was 1:1, and the above process of spraying the tetraammineplatinum acetate solution was completed in one go. During spraying, the circulating refrigeration unit was turned on to cool the hopper, keeping it at a constant temperature of 20°C. During solvent evaporation, the valves of the circulating refrigeration unit were closed, and the circulating heater was turned on to heat the hopper at a constant temperature of 100°C for 1 hour. During vacuuming, the vacuum degree was 80 Pa; the pressurization pressure was 0.5 MPa for 10 minutes.

[0067] The sample was rapidly cooled with liquid nitrogen and then freeze-dried in a freeze dryer to obtain freeze-dried powder. The freeze-drying time was 12 hours.

[0068] The freeze-dried powder was placed in a rotary tube furnace and heat-treated in a reducing gas mixture at 600°C for 2 hours at a heating rate of 5°C / min. The reducing gas mixture consisted of 5 vol% ammonia and the remainder argon. After heat treatment, the desired catalyst, labeled PtC-5, with a platinum loading of 50 wt%, was obtained.

[0069] Comparative Example 2:

[0070] Lion KB300 superconducting carbon black from Japan was mechanically crushed and passed through a 400-mesh sieve for later use. 10g of the crushed carbon black, 0.5g of polyvinylpyrrolidone, and 600g of 2M nitric acid solution were weighed, mixed, and stirred under reflux at 80℃ for 8 hours. After reflux, the carbon black was rinsed with deionized water until the filtrate was neutral. The rinsed carbon black sample was placed in a vacuum drying oven and vacuum dried at 120℃ for 8 hours. After vacuum drying, the carbon black sample was crushed again to obtain the carbon carrier for later use. The carbon black used in the mixing process had a specific surface area of ​​800 m². 2 / g, polyvinylpyrrolidone molecular weight 10000.

[0071] Take 15.63g of tetraammineplatinum acetate and 1305g of a mixed solution (305g of deionized water and 1000g of acetic acid in the mixed solution). At the same time, stir and sonicate the materials for 60 minutes, with an ultrasonic power of 3KW and a temperature of 90℃.

[0072] Eightg of crushed carbon support was placed in the double-jacketed hopper of a dual planetary mixer. After closing the hopper, a vacuum pump was turned on to create a vacuum. Tetraammineplatinum acetate solution was sprayed into the hopper through a spray nozzle. During the spraying of the tetraammineplatinum acetate solution, the dispersion and stirring systems of the dual planetary mixer were activated to continuously disperse and stir the material. After dispersion and stirring, the valve was closed, and the vacuum pump was turned on to evaporate the solvent. The hopper temperature was kept constant at 100°C. In this embodiment, the mass ratio of platinum to the spare carbon support in the tetraammineplatinum acetate solution was 1:1. The tetraammineplatinum acetate solution was divided into three portions. One portion of the platinum precursor solution was sprayed during each spraying. After the above dispersion, stirring, pressurization, and solvent evaporation steps were completed, another portion of the platinum precursor solution was sprayed. This process was repeated until all three portions of the platinum precursor solution were sprayed to obtain the sample. During dispersion and stirring, a circulating refrigeration unit was turned on to cool the hopper, keeping it at a constant temperature of 20°C. The dispersion and stirring time was 60 minutes, and the dispersion rate was 1000 rpm. During solvent evaporation, first close the valve of the circulating refrigeration unit, and at the same time turn on the circulating heater to heat the barrel at a constant temperature of 100°C for 1 hour; when evacuating, the vacuum degree is 80 Pa.

[0073] The sample was rapidly cooled with liquid nitrogen and then freeze-dried in a freeze dryer to obtain freeze-dried powder. The freeze-drying time was 12 hours.

[0074] The freeze-dried powder was placed in a rotary tube furnace and heat-treated in a reducing gas mixture at 600°C for 2 hours at a heating rate of 5°C / min. The reducing gas mixture consisted of 5 vol% ammonia and the remainder argon. After heat treatment, the desired catalyst, labeled PtC-6, with a platinum loading of 50 wt%, was obtained.

[0075] Comparative Example 3:

[0076] Take Lion KB300 superconducting carbon black (Japan) and 0.5g of polyvinylpyrrolidone, mechanically crush and mix them, and then pass them through a 400-mesh sieve for later use. The carbon black used in the mixing process has a specific surface area of ​​800m². 2 / g, polyvinylpyrrolidone molecular weight 10000.

[0077] Take 15.63g of tetraammineplatinum acetate, 1305g of mixed solution (305g of deionized water and 1000g of acetic acid in the mixed solution), and 3.26g of alkylphenol polyoxyethylene ether and put them into a glass reactor. At the same time, the materials are stirred and sonicated for 60 minutes with an ultrasonic power of 3KW and a temperature of 90℃.

[0078] Eightg of crushed carbon black was placed in the double-jacketed hopper of a dual planetary mixer. After closing the hopper, a vacuum pump was turned on to create a vacuum. Tetraammineplatinum acetate solution was sprayed into the hopper through a spray nozzle. During the spraying of the tetraammineplatinum acetate solution, the dispersion and stirring systems of the dual planetary mixer were turned on to continuously disperse and stir the material. After dispersion and stirring, the vacuum pump and valves were turned off, and nitrogen was introduced through the nitrogen valve to pressurize the material. After pressurization, the vacuum pump was turned on to evaporate the solvent, and the hopper temperature was kept constant at 100°C. In this embodiment, the mass ratio of platinum to the spare carbon carrier in the tetraammineplatinum acetate solution was 1:1. The tetraammineplatinum acetate solution was divided into three portions. One portion of the platinum precursor solution was sprayed during each spraying. After the above dispersion, stirring, pressurization, and solvent evaporation steps were completed, another portion of the platinum precursor solution was sprayed. The above steps were repeated until all three portions of the platinum precursor solution were sprayed to obtain the sample. During dispersion and mixing, the circulating refrigeration unit was turned on to cool the barrel, maintaining it at a constant temperature of 20°C. The dispersion and mixing time was 60 minutes, and the dispersion rate was 1000 rpm. During solvent evaporation, the circulating refrigeration unit valve was first closed, and the circulating heater was turned on to heat the barrel at a constant temperature of 100°C for 1 hour. During vacuuming, the vacuum degree was 80 Pa; the pressurization pressure was 0.5 MPa, and the pressurization time was 10 minutes.

[0079] The sample was rapidly cooled with liquid nitrogen and then freeze-dried in a freeze dryer to obtain freeze-dried powder. The freeze-drying time was 12 hours.

[0080] The freeze-dried powder was placed in a rotary tube furnace and heat-treated in a reducing gas mixture at 600°C for 2 hours at a heating rate of 5°C / min. The reducing gas mixture consisted of 5 vol% hydrogen and the remainder argon. After heat treatment, the desired catalyst, labeled PtC-7, with a platinum loading of 50 wt%, was obtained.

[0081] Comparative Example 4:

[0082] The catalyst was synthesized using a microwave-assisted ethylene glycol synthesis method, with Lion KB300 superconducting carbon black from Japan as the carbon support. 500 mL of a 1 mg / mL platinum-containing ethylene glycol chloroplatinate solution was poured into a 1 L glass reactor and stirred for 10 minutes. Then, 30 mL of a 1 M sodium hydroxide ethylene glycol solution was added and stirred continuously for 10 minutes. Next, 100 mL of a 5 mg / mL KB300 superconducting carbon black / ethylene glycol suspension was added and stirred for 10 minutes. The glass reactor was then placed in a microwave reactor and reacted at 160°C for 5 minutes. After the reaction, the slurry was allowed to cool to room temperature. Then, a 0.2 M hydrochloric acid solution was added to the slurry to adjust the pH to 2, accelerating catalyst sedimentation. Finally, the catalyst was filtered out and washed with boiling water at 90–100°C until the filtrate was neutral. The washed catalyst was then dried in a vacuum at 70°C for 12 hours. The dried catalyst was placed in a rotary tube furnace and heat-treated in a reducing mixed gas at 600°C for 2 hours at a heating rate of 5°C / min. The reducing mixed gas consisted of 5 vol% ammonia and the remainder argon. After heat treatment, the desired catalyst, labeled PtC-8, with a platinum loading of 50 wt%, was obtained.

[0083] Comparative Example 5:

[0084] Lion KB300 superconducting carbon black from Japan was mechanically crushed and passed through a 400-mesh sieve for later use. 10g of the crushed carbon black, 0.5g of polyvinylpyrrolidone (molecular weight 10000), and 600g of 2M nitric acid solution were weighed, mixed, and stirred. The mixture was then refluxed at 80℃ for 8 hours. After reflux, the carbon black was rinsed until the filtrate was neutral. The rinsed carbon black sample was placed in a vacuum drying oven and vacuum dried at 120℃ for 8 hours. After vacuum drying, the carbon black sample was crushed again to obtain a spare carbon carrier, which was labeled O-KB300.

[0085] The prepared carbon support powder O-KB300 was placed in a rotary tube furnace and heat-treated in a reducing mixed gas at a temperature of 600℃ for 2 hours at a heating rate of 5℃ / min. The reducing mixed gas consisted of 5 vol% ammonia and the remainder argon. After heat treatment, the desired carbon support, labeled N-KB300, was obtained.

[0086] Test example:

[0087] TEM test: First, scrape off the catalyst on the cathode side of the membrane electrode after circulation with a blade; then take an appropriate amount of the scraped sample and add it to a centrifuge tube with ethanol and water (volume ratio 1:1), and sonicate to mix evenly; drop an appropriate amount of the mixture onto a copper grid, let it dry, and then put it into a transmission electron microscope for testing.

[0088] XRD testing: The catalyst layer before and after cycling was cut into strips 20mm wide and 35mm long with a blade. The cathode side was facing up and the strips were fixed flat on the sample cell with tape. The sample cell was then placed in an XRD analyzer to obtain the XRD pattern of the catalyst layer. The test scan rate was 5° / min and the scanning angle range was 20-80°. Finally, the average particle size of the platinum nanoparticles was calculated according to the Scherrer formula.

[0089] Membrane electrode testing: The prepared platinum-carbon catalyst powder was weighed and added sequentially to a certain proportion of pure water, isopropanol, and Nafion solution. The mixture was ultrasonically homogenized to obtain a catalyst slurry for later use. The mass ratios of the components were as follows: Nafion to carbon 0.7, isopropanol:pure water = 1:1, platinum-carbon catalyst:(mixed solution of isopropanol and pure water) = 1:20. The slurry was loaded into an ultrasonic spraying device and sprayed onto both sides of the proton exchange membrane, with a platinum loading of 0.05 mg / cm³ on the anode side. 2 The cathode platinum loading is 0.3 mg / cm². 2 The membrane electrode assembly was dried at 80°C and then hot-pressed with carbon paper and a frame on a hot press to form a membrane electrode. The prepared membrane electrode was then installed into a test fixture, which was then connected to a fuel cell test bench for testing. The battery temperature was 80°C, the anode relative humidity was 50%, the cathode relative humidity was 30%, the anode and cathode back pressures were both 150 kPa, and the anode and cathode gas metering ratios were both 1.8.

[0090] Carbon support corrosion sensitivity test: 10 mg carbon support, 2.5 mL water, and 2.5 mL isopropanol were placed in a 10 mL glass bottle and sonicated for ten minutes to mix thoroughly. Then, 100 μL of Nafion solution (D520) was added, and sonication was continued for another ten minutes. All sonication was performed in an ice-water bath. The resulting mixture was then dropped onto a disc electrode, with a carbon support loading of 40 μg / cm³. 2 After the added material was dried, the corrosion sensitivity of the carbon support was tested. The test steps were as follows: ① CV test voltage range: 0.05-1.0V, scan rate: 10mV / s; ② 0.8V constant voltage for 10s, 1.4V constant voltage for 50s, repeating this step 10 times; ③ CV test voltage range: 0.05-1.0V, scan rate: 10mV / s; the test system was a 0.1M nitrogen-saturated perchloric acid solution, and the test temperature was 25℃. The ratio of the integral area of ​​the CV curves in step ③ to that in step ① is the value characterizing the corrosion sensitivity of the carbon support.

[0091] Table 1. Comparison of voltage values ​​at different current densities in the membrane electrode test data of catalyst samples.

[0092]

[0093] like Figures 1 to 14As shown in Table 1, the test results of Example 1 demonstrate that the process of this invention has good feasibility and can prepare Pt / C catalysts with excellent electrochemical performance. Comparative Example 1, compared to Example 1, only changed the number of times the platinum precursor solution was sprayed and did not involve turning on the dispersion / stirring system. Comparative Example 2, compared to Example 1, did not involve the amount of additives added or nitrogen pressurization treatment. From the TEM test results (such as...) Figure 1 , 2 As shown in Figure 3, reducing the number of times the platinum precursor solution is sprayed and operating without a dispersion / stirring system leads to the growth of platinum nanoparticles and uneven size distribution, resulting in a decrease in the initial activity of the catalyst (e.g., ...). Figure 5 (As shown in Table 1) This is because spraying the platinum precursor solution in small, multiple applications allows the platinum salt to penetrate more deeply into the pores of the carbon support. The activation of the dispersion / stirring system promotes uniform mixing of the materials during the impregnation of the carbon support with the platinum precursor solution, preventing most of the platinum salt from concentrating and adsorbing on the surface of the carbon support or in the pores of the carbon support aggregate, thus preventing agglomeration and the formation of larger particles during subsequent thermal reduction. The presence of additives can improve the stability and dispersibility of platinum salts in solution and enhance the flowability of the platinum salt precursor, enabling the platinum salt to quickly and uniformly coat the surface of the carbon support. Nitrogen pressurization further promotes the penetration of the platinum salt precursor solution into the pores of the carbon support. When additives and nitrogen pressurization are lacking, the platinum precursor solution is difficult to uniformly cover the surface of the carbon support and penetrate into the pores, resulting in significant disadvantages in the dispersion and size control of platinum nanoparticles. Platinum nanoparticles are also more prone to dissolution, migration, agglomeration, and detachment during electrochemical cycling (e.g., ...). Figure 9 (As shown).

[0094] Comparative Example 4 employed the traditional ethylene glycol liquid-phase reduction method. In this process, the platinum precursor could not penetrate significantly into the pores of the carbon support, resulting in most platinum nanoparticles remaining on the carbon support surface. These platinum nanoparticles on the carbon support surface were in direct contact with the ionomers and were severely poisoned, leading to low catalyst activity. Because most of the platinum nanoparticles were located on the carbon support surface, they were more prone to dissolution, migration, aggregation, and detachment, thus significantly reducing catalyst stability (e.g., ...). Figure 7 (As shown in Table 1).

[0095] Compared to Example 1, Comparative Example 3 lacks the carbon support pretreatment process and the reducing gas does not contain a nitrogen source. The pretreatment process can uniformly introduce oxygen-containing groups on the carbon support surface. TEM images from Example 1 show that the catalyst sample has almost no agglomerated platinum nanoparticles and the platinum nanoparticles are uniformly dispersed. This indicates that oxygen-containing groups can serve as adsorption and precipitation sites for platinum salts, which is beneficial for promoting the uniform distribution of platinum salts on the carbon support surface, resulting in smaller and more uniformly dispersed platinum nanoparticles (such as...). Figure 1 , 4(As shown in Figure 11). Furthermore, the aforementioned oxygen-containing groups can react with nitrogen sources in the gas and those from the thermal decomposition of the platinum salt precursor during subsequent heat treatment, converting the oxygen-containing groups (such as -OH, -COOH) into nitrogen-containing groups (such as -NH2, -CONH2). Figure 13 As shown in the figure, through strong interactions between nitrogen-containing groups and platinum nanoparticles, the platinum nanoparticles are firmly anchored to the carbon support surface. This can mitigate the dissolution, migration, aggregation, and detachment of platinum nanoparticles during electrochemical cycling, thereby enhancing the stability of the catalyst system (e.g., Figure 8 , 10 (See Table 1). The presence of nitrogen-containing groups can improve the electronic structure of adjacent active components and enhance the catalytic activity of the catalyst system. Furthermore, the positively charged nitrogen-containing groups, through the interaction between charges, can promote the uniform coverage of negatively charged ionomers on the surface of the nitrogen-functionalized carbon support, thereby significantly reducing local oxygen mass transfer resistance. In summary, the introduction of nitrogen-containing groups onto the carbon support can improve the interaction among the carbon support, platinum nanoparticles, and ionomers, thereby achieving high activity and high stability of the catalyst (e.g., ...). Figure 5 , 6 (as shown in Table 1).

[0096] Aside from the special case of high interfacial potential difference corrosion of carbon supports caused by the hydrogen-air interface, carbon supports in catalysts, especially in areas with low graphitization or defects, preferentially undergo oxidative corrosion during electrochemical cycling. For example... Figure 14 As shown in the figure, the corrosion sensitivity test of the carbon support in Comparative Example 5 indicates that the O-KB300 carbon support oxidized by nitric acid pretreatment is the most susceptible to corrosion, with a corrosion sensitivity value of 313.5%. The corrosion sensitivity values ​​of N-KB300 and KB300 are 257.6% and 243.9%, respectively, which are very close. This indicates that polyvinylpyrrolidone, as a defect repair agent on the surface of the carbon support, can effectively repair the defects caused by oxidation on the surface of the KB300 support, thereby restoring the corrosion resistance of the carbon support to a certain extent and thus improving the service life of the catalyst.

[0097] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a hydrogen fuel cell catalyst, characterized in that, Includes the following steps: Step S1: Mix crushed carbon black, polyvinylpyrrolidone, and a 0.5-5M nitric acid solution, heat to 60-120℃ and reflux for 3-12 hours, then rinse the carbon black with deionized water until the filtrate is neutral. Dry the rinsed carbon black under vacuum at 100-200℃ for 6-12 hours to obtain pretreated conductive carbon black. Finally, crush the pretreated conductive carbon black to obtain a usable carbon carrier. When mixing carbon black, polyvinylpyrrolidone, and nitric acid solution, the mass ratio of carbon black to polyvinylpyrrolidone is 10-30:1, and the mass ratio of carbon black to nitric acid solution is 1:30-100. Step S2: Dissolve platinum precursor powder and additives in a mixed solution of deionized water and organic liquid. Stir the mixture at 80-100℃ and with an ultrasonic power of not less than 2KW for 0.5-1h to obtain a platinum precursor solution. The mass ratio of deionized water to organic liquid is 1:1-20, the mass ratio of platinum precursor powder to mixed solution is 1:20-200, and the mass ratio of additives to mixed solution is 1:100-500. Step S3: Place the spare carbon carrier in the barrel, close the barrel and evacuate it to maintain a vacuum level of no more than 200 Pa. Spray the platinum precursor solution into the barrel. During spraying, maintain the barrel at a constant temperature of 20-25°C and continuously disperse and stir the material in the barrel at a dispersion rate of 500-2000 rpm for 10-60 min. After dispersion and stirring, stop evacuating the vacuum and introduce nitrogen into the barrel to pressurize the material at a pressure of 0.1-0.5 MPa for 5-20 min. After pressurization, the barrel is evacuated again to maintain a vacuum level not exceeding 200 Pa and the barrel is kept at a constant temperature of 100°C for solvent evaporation for 1-2 hours. The mass ratio of platinum to carbon support in the platinum precursor solution is 1:0.5-4. The platinum precursor solution is divided into at least three portions. One portion of the platinum precursor solution is sprayed during each spraying. After the above dispersion, stirring, pressurization and solvent evaporation steps are completed, another portion of the platinum precursor solution is sprayed. The above steps are repeated until all platinum precursor solutions are sprayed to obtain the sample. Step S4: The sample obtained in step S3 is rapidly cooled with liquid nitrogen and then freeze-dried in a freeze dryer for 8-24 hours to obtain freeze-dried powder. Step S5: Heat-treat the freeze-dried powder in a reducing mixed gas at a temperature of 400~900℃ for 1~3h to obtain the catalyst; wherein, the reducing mixed gas includes 5~10Vol% of reducing gas ammonia, and the remainder is argon or nitrogen.

2. The method for preparing a hydrogen fuel cell catalyst according to claim 1, characterized in that, In step S1, the carbon black added during the mixing of carbon black, polyvinylpyrrolidone, and nitric acid solution has a specific surface area of ​​400-1200 m². 2 / g, the added carbon black is mechanically crushed and passed through a 400-mesh sieve, and the graphite crystallite size of the carbon black is 2~5nm.

3. The method for preparing a hydrogen fuel cell catalyst according to claim 1, characterized in that, The molecular weight of the polyvinylpyrrolidone is not higher than 40,000.

4. The method for preparing a hydrogen fuel cell catalyst according to claim 1, characterized in that, The platinum precursor powder is any one or a combination of two or more of the following: tetraammineplatinum dibicarbonate, tetraammineplatinum oxalate, tetraammineplatinum hydrogen phosphate, tetraammineplatinum acetate, tetraammineplatinum sulfate, tetraammineplatinum nitrate, diammineplatinum dinitroso, tetraammineplatinum dichloro, ammonium chloroplatinate, and tetraammineplatinum dihydroxoxide.

5. The method for preparing a hydrogen fuel cell catalyst according to claim 1, characterized in that, The additive is any one of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and fatty acyl alkanolamine polyoxyethylene ether.

6. The method for preparing a hydrogen fuel cell catalyst according to claim 1, characterized in that, The organic liquid is any one or a combination of two or more of isopropanol, n-propanol, glycerol, acetic acid, and trichloroacetaldehyde.

7. A hydrogen fuel cell catalyst, characterized in that, The catalyst prepared by any one of the hydrogen fuel cell catalyst preparation methods according to claims 1 to 6.

Images