A platinum-cerium alloy catalyst, a preparation method and application thereof

Abstract

The application discloses a preparation method of a platinum-cerium alloy catalyst, and comprises the following steps: dissolving a platinum precursor salt and a cerium precursor salt in deionized water to obtain solution A; dispersing carbon powder in ethylene glycol or an ethylene glycol aqueous solution to obtain solution B; mixing solution A and solution B, stirring for 1-3 hours, adjusting the pH to alkaline through an alkali solution and stirring for 0.5-2 hours, adding a surfactant and stirring for 2-4 hours to obtain mixed solution C; and placing the mixed solution C in a microwave reactor, and performing 5-10 cycles of microwave start / stop to obtain the platinum-cerium alloy catalyst. The application adopts co-precipitation and microwave-assisted reaction to prepare the alloy catalyst, simplifies the production process, greatly reduces the production cycle and cost, and has the advantages of small particle size, narrow distribution range, uniform dispersion of each metal component in the particles and the like compared with existing alloy catalyst products, can better play the catalyst performance, and is suitable for industrial batch production.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to a platinum-cerium alloy catalyst, its preparation method, and its application. Background Technology

[0002] Hydrogen fuel cells are a type of highly efficient and clean power generation device. They only require hydrogen and air to undergo oxidation and reduction reactions respectively to produce water and generate electricity. They have advantages such as low noise, no pollution, and high energy conversion efficiency, and are widely used.

[0003] In a fuel cell, the catalyst is the site of the reaction between hydrogen and oxygen. Hydrogen is introduced at the anode for oxidation, while oxygen is introduced at the cathode for reduction. During the oxygen reduction process at the cathode, certain free radical intermediates are typically generated due to the intrinsic properties of the catalyst. These free radicals, in conjunction with metal ions, corrode and decompose the perfluorosulfonic acid proton exchange membrane and the catalyst support, thereby affecting the lifespan of the catalyst and membrane electrode assembly.

[0004] Currently, to improve catalyst performance, researchers are attempting to fabricate platinum-based transition metal alloy catalysts (such as platinum-cobalt alloys and platinum-nickel alloys). However, the transition metal ions and free radicals in these catalysts exacerbate the corrosion and decomposition of the proton exchange membrane and catalyst support, resulting in poor durability of the catalyst and membrane electrode assembly (MEA). Researchers have also introduced cerium into platinum-carbon catalysts, which not only improves catalyst performance but also quenches the generated free radicals, reducing their impact and improving the durability of the catalyst and MEA. The preparation of alloy catalysts often employs a stepwise loading process, using high-temperature alloying. This process is relatively complex, resulting in uneven catalyst particle size distribution and poor product consistency, which is detrimental to scale-up production.

[0005] Therefore, a simple and easy-to-implement method for manufacturing fuel cell alloy catalysts is needed to achieve the goal of mass production of alloy catalysts. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a method for preparing a platinum-cerium alloy catalyst. The method employs co-precipitation and microwave-assisted reaction to prepare the alloy catalyst, eliminating the need for high-temperature alloying, simplifying the production process, and significantly reducing the production cycle and cost. Compared with existing alloy catalyst products, this method has advantages such as a narrow particle size distribution range and uniform dispersion of each metal component in the particles, enabling better performance of the catalyst and making it suitable for industrial mass production.

[0007] To address the aforementioned technical problems, the first aspect of this invention provides a method for preparing a platinum-cerium alloy catalyst, comprising the following steps:

[0008] S1. Dissolve platinum precursor salt and cerium precursor salt in deionized water to obtain solution A;

[0009] S2. Disperse the carbon powder in ethylene glycol or an aqueous solution of ethylene glycol to obtain solution B;

[0010] S3. At room temperature, solution A and solution B are mixed and stirred for 1-3 hours. The pH is adjusted to alkaline by alkali solution and stirred for 0.5-2 hours. A surfactant is added and stirred for 2-4 hours to obtain mixture C.

[0011] S4. Place the mixture C in a microwave reactor and cycle it 5-10 times under room temperature conditions to obtain a platinum-cerium alloy catalyst.

[0012] The total mass fraction of platinum and cerium in the catalyst is 30-60 wt%.

[0013] This invention employs a metal ion co-deposition and microwave-assisted method to prepare a platinum-cerium alloy catalyst. The process is simple and low-cost. By controlling the amounts of reducing agent and carbon source, as well as the platinum-cerium metal ratio, the crystal structure and particle size of the alloy catalyst can be altered, thereby improving catalyst performance and lifespan. Specifically: First, a metal precursor is mixed in deionized water, and carbon powder is added to an ethylene glycol aqueous solution. The two dispersions are then mixed to ensure thorough mixing of the reducing agent (ethylene glycol), carbon powder, and precursor salt, guaranteeing uniformity of the reaction system components. Second, sodium hydroxide solution is added, causing the metal salt in the solution to co-precipitate onto the carbon support, forming a mixed hydroxide. The resulting alloy particles exhibit a relatively uniform alloy structure and particle size distribution. Third, a surfactant is added. Utilizing the surfactant's high molecular weight and high stability, it adsorbs onto the carbon support, coating and immobilizing the metal particles. Simultaneously, the viscosity and reduction intensity of the reaction system are adjusted by changing the concentration of the reducing agent, ensuring sufficient reduction while maintaining system homogeneity during the reaction. Finally, cyclic microwave treatment ensures sufficient reduction while controlling the reaction temperature as much as possible to prevent catalyst particle agglomeration due to excessive temperature.

[0014] Furthermore, in S1, the platinum precursor salt is selected from one or more of chloroplatinic acid, platinum tetrachloride, dichlorodiammineplatinum, platinum acetylacetonate, and tetraammineplatinum; the cerium precursor salt is selected from one or more of cerium trichloride, cerium nitrate, cerium acetylacetonate, and cerium sulfate.

[0015] Furthermore, in S1, the molar ratio of platinum to cerium in the platinum precursor salt and the cerium precursor salt is 1:(0.3-0.5); the concentration of the platinum precursor salt in solution A is 15.8-19.9 g / L; and the concentration of the cerium precursor salt in solution A is 2.8-4.2 g / L.

[0016] Furthermore, in S2, the concentration of the carbon powder in solution B is 10-18.5 g / L.

[0017] Furthermore, in S2, the mixture is stirred and dispersed at 80-90°C and then cooled to room temperature for later use.

[0018] Furthermore, in S2, the concentration of ethylene glycol in the ethylene glycol aqueous solution is above 10 wt%.

[0019] Furthermore, in S3, the surfactant is selected from one or more of fatty alcohol polyoxyethylene ether, polyvinylpyrrolidone, P123, and N,N-dihydroxyethyl fatty amide.

[0020] Furthermore, in step S3, the alkaline solution is an aqueous solution of sodium hydroxide with a pH of 8.5-10. Even further, the concentration of the aqueous solution of sodium hydroxide is 0.05-1 mol / L.

[0021] Furthermore, in S4, the parameters of the microwave are: frequency 2200-2600MHz, power 500-700W, single start time 55-65s, and single stop time 40-50s.

[0022] Furthermore, after S4, the process includes washing the filter with deionized water until the conductivity of the filtrate is less than 10 μS / cm, and drying it at 110-130°C.

[0023] The second aspect of the present invention provides a platinum-cerium alloy catalyst prepared by the preparation method described in the first aspect.

[0024] The third aspect of this invention provides the application of the platinum-cerium alloy catalyst described in the second aspect in fuel cells.

[0025] The beneficial effects of this invention are:

[0026] (1) The present invention prepares an alloy catalyst by platinum and cerium metal co-deposition and microwave-assisted reaction. By controlling the content of each component, the crystal structure and particle size of the alloy catalyst are regulated, thereby improving the catalyst performance and lifespan.

[0027] (2) In the microwave-assisted reaction stage, this invention selects an intermittent microwave reaction method. By using a microwave-started and stopped reaction mode, the reduction of each metal component in the catalyst is ensured, and the crystallinity of the catalyst alloy particles is improved. At the same time, it reduces the agglomeration of metal particles caused by excessively high temperatures and maintains a good particle size distribution.

[0028] (3) The experimental conditions required by this invention are relatively mild, and there is no need for a high-temperature alloying process. The resulting alloy catalyst particles have a narrow particle size distribution and good product consistency. At the same time, the method is simple and can be industrialized. Attached Figure Description

[0029] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is the voltammetric cycle curve of the catalyst in Example 3 of the present invention;

[0031] Figure 2 This is the oxygen reduction polarization curve of the catalyst in Example 3 of the present invention;

[0032] Figure 3 This is the polarization curve of the membrane electrode prepared by the catalyst in Example 3 of the present invention. Detailed Implementation

[0033] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] This embodiment relates to a method for preparing a platinum-cerium alloy catalyst, comprising the following steps:

[0035] S1. Dissolve platinum precursor salt and cerium precursor salt in deionized water to obtain solution A;

[0036] S2. Disperse the carbon powder in ethylene glycol or an aqueous solution of ethylene glycol to obtain solution B;

[0037] S3. At room temperature, solution A and solution B are mixed and stirred for 1-3 hours. The pH is adjusted to alkaline by alkali solution and stirred for 0.5-2 hours. A surfactant is added and stirred for 2-4 hours to obtain mixture C.

[0038] S4. Place the mixture C in a microwave reactor and cycle it 5-10 times under room temperature conditions to obtain a platinum-cerium alloy catalyst.

[0039] The total mass fraction of platinum and cerium in the catalyst is 30-60 wt%.

[0040] This embodiment uses metal ion co-deposition and microwave-assisted methods to prepare platinum-cerium alloy catalysts. The process is simple and low-cost. By controlling the amount of reducing agent and carbon source, as well as the ratio of platinum and cerium metal, the crystal structure and particle size of the alloy catalyst can be changed. By changing the concentration of reducing agent, the viscosity and reduction intensity of the reaction system can be adjusted to ensure that the system remains uniform during the reaction and is fully reduced. The resulting catalyst has a narrow particle size distribution, good product consistency, and excellent catalyst performance and lifespan.

[0041] In this embodiment, a metal precursor is mixed in deionized water, and carbon powder is added to an ethylene glycol aqueous solution. The two dispersions are then mixed to ensure thorough mixing of the reducing agent ethylene glycol, carbon powder, and precursor salt, guaranteeing uniformity of the components in the reaction system. The addition of sodium hydroxide solution causes the metal salt in the solution to co-precipitate onto the carbon support, forming a mixed hydroxide. The resulting alloy particles exhibit a relatively uniform alloy structure and particle size distribution. Furthermore, a surfactant is added. Utilizing the surfactant's high molecular weight and high stability, it adsorbs onto the carbon support, coating the metal particles and providing fixation. Cyclic microwave treatment ensures the reduction of each metal component in the catalyst, improves the crystallinity of the catalyst alloy particles, and prevents catalyst particle agglomeration due to excessively high temperatures.

[0042] In a preferred embodiment, in S1, the platinum precursor salt is selected from one or more of chloroplatinic acid, platinum tetrachloride, dichlorodiammineplatinum, platinum acetylacetonate, and tetraammineplatinum; the cerium precursor salt is selected from one or more of cerium trichloride, cerium nitrate, cerium acetylacetonate, and cerium sulfate. The molar ratio of platinum to cerium in the platinum precursor salt and the cerium precursor salt is 1:(0.3-0.5); the concentration of the platinum precursor salt in solution A is 15.8-19.9 g / L; and the concentration of the cerium precursor salt in solution A is 2.8-4.2 g / L.

[0043] In a preferred embodiment, in step S2, the mixture is stirred and dispersed at 80-90°C and then cooled to room temperature for later use. The concentration of the carbon powder in solution B is 10-18.5 g / L. The concentration of ethylene glycol in the ethylene glycol aqueous solution is above 10 wt%.

[0044] In a preferred embodiment, in S3, the surfactant is selected from one or more of fatty alcohol polyoxyethylene ether, polyvinylpyrrolidone, P123, and N,N-dihydroxyethyl fatty amide; the alkaline solution is an aqueous sodium hydroxide solution with a pH of 8.5-10, and more specifically, the concentration of the aqueous sodium hydroxide solution is 0.05-1 mol / L.

[0045] In a preferred embodiment, in step S4, the microwave parameters are: frequency 2200-2600MHz, power 500-700W, single start-up time 55-65s, and single stop time 40-50s. Step S4 is followed by washing and filtering with deionized water until the filtrate conductivity is less than 10μS / cm, and drying at 110-130℃.

[0046] Another embodiment relates to a platinum-cerium alloy catalyst prepared by the preparation method described in the above embodiments.

[0047] Another embodiment relates to the application of the platinum-cerium alloy catalyst described in the above embodiments in a fuel cell.

[0048] Example 1

[0049] This embodiment relates to a method for preparing a platinum-cerium alloy catalyst, comprising the following steps:

[0050] (1) Add 53.6g of chloroplatinic acid hexahydrate and 8.5g of cerium trichloride to 3000g of deionized water and stir until completely dissolved to obtain solution A.

[0051] (2) Add 25g of carbon powder to 2000g of ethylene glycol aqueous solution (ethylene glycol mass fraction 15wt%) and stir at 90℃ for 3h to obtain mixture B.

[0052] (3) After the mixture B has cooled to room temperature, add solution A to the mixture B and stir for 2 hours.

[0053] (4) Slowly add 0.07 mol / L sodium hydroxide solution to the mixture until pH = 8.5, and stir at room temperature for 1 h.

[0054] (5) Then add 17.5g of polyvinylpyrrolidone and stir at room temperature for 3h to obtain mixture C.

[0055] (6) Place the mixture C in a microwave reactor and stir continuously. Set the microwave parameters as follows: 2450MHz, 600W, start at 60s and stop at 45s. Repeat the reaction 7 times to prepare the alloy catalyst and obtain the catalyst sample.

[0056] (7) Wash and filter the catalyst sample with deionized water until the conductivity of the filtrate is less than 10 μS / cm.

[0057] (8) The washed catalyst sample was dried in a vacuum drying oven at 120°C for 48 hours to obtain a platinum-cerium alloy catalyst, wherein the molar ratio of platinum to cerium was 3:1.

[0058] Example 2

[0059] The difference between this embodiment and Embodiment 1 is that the mass fraction of ethylene glycol in the aqueous ethylene glycol solution is adjusted to 45%, specifically:

[0060] (1) Add 53.6g of chloroplatinic acid hexahydrate and 8.5g of cerium trichloride to 3000g of deionized water and stir until completely dissolved to obtain solution A.

[0061] (2) Add 25g of carbon powder to 2000g of ethylene glycol aqueous solution (ethylene glycol mass fraction 45wt%) and stir at 90℃ for 3h to obtain mixture B.

[0062] (3) After the mixture B has cooled to room temperature, add solution A to the mixture B and stir for 2 hours.

[0063] (4) Slowly add 0.07 mol / L sodium hydroxide solution to the mixture until pH = 8.5, and stir at room temperature for 1 h.

[0064] (5) Then add 17.5g of polyvinylpyrrolidone and stir at room temperature for 3h to obtain mixture C.

[0065] (6) Place the mixture C in a microwave reactor and stir continuously. Set the microwave parameters as follows: 2450MHz, 600W, start at 60s and stop at 45s. Repeat the reaction 7 times to prepare the alloy catalyst and obtain the catalyst sample.

[0066] (7) Wash and filter the catalyst sample with deionized water until the conductivity of the filtrate is less than 10 μS / cm.

[0067] (8) The washed catalyst sample was dried in a vacuum drying oven at 120°C for 48 hours to obtain a platinum-cerium alloy catalyst, wherein the molar ratio of platinum to cerium was 3:1.

[0068] Example 3

[0069] The difference between this embodiment and Embodiment 1 is that the mass fraction of ethylene glycol in the aqueous ethylene glycol solution is adjusted to 62.5%, specifically:

[0070] (1) Add 53.6g of chloroplatinic acid hexahydrate and 8.5g of cerium trichloride to 3000g of deionized water and stir until completely dissolved to obtain solution A.

[0071] (2) Add 25g of carbon powder to 2000g of ethylene glycol aqueous solution (ethylene glycol mass fraction 62.5wt%) and stir at 90℃ for 3h to obtain mixture B.

[0072] (3) After the mixture B has cooled to room temperature, add solution A to the mixture B and stir for 2 hours.

[0073] (4) Slowly add 0.07 mol / L sodium hydroxide solution to the mixture until pH = 8.5, and stir at room temperature for 1 h.

[0074] (5) Then add 17.5g of polyvinylpyrrolidone and stir at room temperature for 3h to obtain mixture C.

[0075] (6) Place the mixture C in a microwave reactor and stir continuously. Set the microwave parameters as follows: 2450MHz, 600W, start at 60s and stop at 45s. Repeat the reaction 7 times to prepare the alloy catalyst and obtain the catalyst sample.

[0076] (7) Wash and filter the catalyst sample with deionized water until the conductivity of the filtrate is less than 10 μS / cm.

[0077] (8) The washed catalyst sample was dried in a vacuum drying oven at 120°C for 48 hours to obtain a platinum-cerium alloy catalyst, wherein the molar ratio of platinum to cerium was 3:1.

[0078] Example 4

[0079] The difference between this embodiment and Embodiment 1 is that the aqueous ethylene glycol solution is replaced with ethylene glycol, specifically:

[0080] (1) Add 53.6g of chloroplatinic acid hexahydrate and 8.5g of cerium trichloride to 3000g of deionized water and stir until completely dissolved to obtain solution A.

[0081] (2) Add 25g of carbon powder to 2000g of ethylene glycol and stir at 90℃ for 3h to obtain mixture B.

[0082] (3) After the mixture B has cooled to room temperature, add solution A to the mixture B and stir for 2 hours.

[0083] (4) Slowly add 0.07 mol / L sodium hydroxide solution to the mixture until pH = 8.5, and stir at room temperature for 1 h.

[0084] (5) Then add 17.5g of polyvinylpyrrolidone and stir at room temperature for 3h to obtain mixture C.

[0085] (6) Place the mixture C in a microwave reactor and stir continuously. Set the microwave parameters as follows: 2450MHz, 600W, start at 60s and stop at 45s. Repeat the reaction 7 times to prepare the alloy catalyst and obtain the catalyst sample.

[0086] (7) Wash and filter the catalyst sample with deionized water until the conductivity of the filtrate is less than 10 μS / cm.

[0087] (8) The washed catalyst sample was dried in a vacuum drying oven at 120°C for 48 hours to obtain a platinum-cerium alloy catalyst, wherein the molar ratio of platinum to cerium was 3:1.

[0088] Comparative Example 1

[0089] The difference between this comparative example and Example 3 is that the concentrations and ratios of chloroplatinic acid hexahydrate and cerium trichloride are adjusted, specifically:

[0090] (1) Add 38.6g of chloroplatinic acid hexahydrate and 18.4g of cerium trichloride to 3000g of deionized water and stir until completely dissolved to obtain solution A.

[0091] (2) Add 25g of carbon powder to 2000g of ethylene glycol aqueous solution (ethylene glycol mass fraction 62.5wt%) and stir at 90℃ for 3h to obtain mixture B.

[0092] (3) After the mixture B has cooled to room temperature, add solution A to the mixture B and stir for 2 hours.

[0093] (4) Slowly add 0.07 mol / L sodium hydroxide solution to the mixture until pH = 8.5, and stir at room temperature for 1 h.

[0094] (5) Then add 17.5g of polyvinylpyrrolidone and stir at room temperature for 3h to obtain mixture C.

[0095] (6) Place the mixture C in a microwave reactor and stir continuously. Set the microwave parameters as follows: 2450MHz, 600W, start at 60s and stop at 45s. Repeat the reaction 7 times to prepare the alloy catalyst and obtain the catalyst sample.

[0096] (7) Wash and filter the catalyst sample with deionized water until the conductivity of the filtrate is less than 10 μS / cm.

[0097] (8) The washed catalyst sample was dried in a vacuum drying oven at 120°C for 48 hours to obtain a platinum-cerium alloy catalyst, wherein the molar ratio of platinum to cerium was 1:1.

[0098] Comparative Example 2

[0099] The difference between this comparative example and Example 3 is that the concentrations and ratios of chloroplatinic acid hexahydrate and cerium trichloride are adjusted, specifically:

[0100] (1) Add 21.1g of chloroplatinic acid hexahydrate and 30.0g of cerium trichloride to 3000g of deionized water and stir until completely dissolved to obtain solution A.

[0101] (2) Add 25g of carbon powder to 2000g of ethylene glycol aqueous solution (ethylene glycol mass fraction 62.5wt%) and stir at 90℃ for 3h to obtain mixture B.

[0102] (3) After the mixture B has cooled to room temperature, add solution A to the mixture B and stir for 2 hours.

[0103] (4) Slowly add 0.07 mol / L sodium hydroxide solution to the mixture until pH = 8.5, and stir at room temperature for 1 h.

[0104] (5) Then add 17.5g of polyvinylpyrrolidone and stir at room temperature for 3h to obtain mixture C.

[0105] (6) Place the mixture C in a microwave reactor and stir continuously. Set the microwave parameters as follows: 2450MHz, 600W, start at 60s and stop at 45s. Repeat the reaction 7 times to prepare the alloy catalyst and obtain the catalyst sample.

[0106] (7) Wash and filter the catalyst sample with deionized water until the conductivity of the filtrate is less than 10 μS / cm.

[0107] (8) The washed catalyst sample was dried in a vacuum drying oven at 120°C for 48 hours to obtain a platinum-cerium alloy catalyst, wherein the molar ratio of platinum to cerium was 1:3.

[0108] Test Example 1

[0109] The average particle size of the platinum metal particles in the alloy catalysts obtained in Examples 1-4 and Comparative Examples 1-2 was calculated based on the XRD patterns, and the results are shown in Table 1.

[0110] Table 1

[0111]

[0112] As shown in Table 1, the particle sizes of the platinum particles in the platinum-cerium alloy catalysts obtained in Example 3 and Comparative Examples 1 and 2 are 4.1 nm, 5.8 nm, and 7.3 nm, respectively. This indicates that different platinum-cerium ratios significantly affect the particle size and structure of the catalyst metal particles, further influencing catalytic activity and catalyst lifetime. Catalysts with larger particles generally exhibit relatively poorer performance. Furthermore, as shown in Examples 1-4, changing the concentration of the reducing agent during synthesis affects the viscosity of the solution, thereby altering the dispersibility of the carrier carbon powder and metal particles, and consequently affecting the particle size. The smallest particle size was obtained under the reducing agent concentration conditions in Example 3.

[0113] Test Example 2

[0114] Electrochemical tests were conducted on the platinum-cerium alloy catalysts obtained in Examples 1-4 and Comparative Examples 1-2. The intrinsic performance of the platinum-cerium alloy catalysts was evaluated by calculating the electrochemical active area and mass activity, and the results are shown in Table 2. It can be seen that there is a positive correlation between the electrochemical active area and the mass activity; the higher the electrochemical active area, the higher the mass activity and the better the catalyst performance. Among the catalysts in Examples 1-4, the catalyst under the conditions of Example 3 exhibited the highest performance. Combined with the average particle size of the catalyst metal in Test 1, it can be concluded that the catalyst under the synthesis conditions of Example 3 had the best performance. The test results of Comparative Examples 1-2 show that the performance of the platinum-cerium alloy catalysts all decreased significantly. This is attributed to the fact that different platinum-cerium ratios in the catalysts affected the structure and metal particle size of the platinum-cerium alloy, thus altering the catalyst performance.

[0115] Table 2

[0116]

[0117] Figure 1-2 The RDE electrochemical CV curves and oxygen reduction polarization curves of the platinum-cerium alloy catalyst with a total metal loading of 50 wt% in Example 3 are shown to determine its performance. As can be seen from the figures, the peak shape structure of the platinum-cerium alloy catalyst in the hydrogen adsorption region differs from that of the platinum-carbon catalyst, indicating that cerium has been doped into platinum, possibly forming an alloy.

[0118] Test Example 3

[0119] The platinum-cerium alloy catalysts obtained in Examples 1-4 and Comparative Examples 1-2 were used to prepare cathodes with a platinum loading of 0.2 g Pt / cm² by ultrasonic spraying. 2 The membrane electrode (anode platinum loading of 0.05 gPt / cm) 2 Using a 20wt% commercial platinum-carbon catalyst, the effect of a platinum-cerium alloy catalyst on a membrane electrode was evaluated, and the results are shown in Table 3. The preparation conditions for the platinum-cerium catalyst membrane electrode were as follows: 0.3g of platinum-cerium alloy catalyst was wetted with 15g of deionized water, followed by the addition of 15g of isopropanol and 2.4g of 5wt% D520 resin. The mixture was placed in a constant-temperature ultrasonic machine at 20℃ and simultaneously subjected to high-speed shearing at 10000rpm for 2 hours to obtain a platinum-cerium alloy catalyst slurry. The slurry was injected into a spraying syringe with a flow rate of 0.5ml / min, an adsorption heating plate temperature of 90℃, and a spraying area of ​​5×5cm. 2 A 12μm proton exchange membrane was placed on the adsorption plate, and vacuum adsorption was initiated. The spraying program was then started. The number of spray passes was controlled to ensure that the platinum loading of the anode platinum-carbon catalyst was 0.05 g Pt / cm³. 2 The platinum loading of the cathode platinum-cerium alloy catalyst is 0.2 g Pt / cm³. 2Cut suitable carbon paper and frames, assemble them into five-in-one or seven-in-one components, and prepare film electrodes.

[0120] Table 3 shows that the catalysts obtained in Examples 1-4 exhibited varying degrees of degradation after 10,000 accelerated aging cycles. This suggests that the synthesis conditions affected the structure of the platinum and cerium metal components in the catalysts, leading to differences in their stability. The membrane electrode prepared using the catalyst obtained in Example 3 showed the best stability, maintaining a stability of 2 A / cm² after 10,000 accelerated aging cycles. 2 At a current density of only 1.91%, the degradation was minimal. Comparative Examples 1-2 show that increasing the cerium content in the catalyst helps improve membrane electrode stability, but leads to a significant decrease in membrane electrode activity. Therefore, considering both catalyst and membrane electrode activity and stability, the platinum-cerium alloy catalyst obtained in Example 3 exhibits both high activity and good stability, demonstrating excellent overall performance. Figure 3 The polarization curve of the membrane electrode prepared by the platinum-cerium alloy catalyst obtained in Example 3 demonstrates the good membrane electrode performance of the alloy catalyst under medium and low electron density.

[0121] Table 3

[0122]

[0123] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A method for preparing a platinum-cerium alloy catalyst, characterized in that, The steps include the following: S1. Dissolve platinum precursor salt and cerium precursor salt in deionized water to obtain solution A; the molar ratio of platinum to cerium in the platinum precursor salt and cerium precursor salt is 1:(0.3-0.5); the concentration of the platinum precursor salt in solution A is 15.8-19.9 g / L; the concentration of the cerium precursor salt in solution A is 2.8-4.2 g / L; S2. Disperse the carbon powder in ethylene glycol or an aqueous solution of ethylene glycol to obtain solution B; S3. At room temperature, solution A and solution B are mixed and stirred for 1-3 hours. The pH is adjusted to alkaline by alkali solution and stirred for 0.5-2 hours. A surfactant is added and stirred for 2-4 hours to obtain mixture C. The surfactant is selected from one or more of fatty alcohol polyoxyethylene ether, polyvinylpyrrolidone, P123, and N,N-dihydroxyethyl fatty amide. S4. Place the mixture C in a microwave reactor and cycle it 5-10 times under room temperature conditions to obtain a platinum-cerium alloy catalyst. The total mass fraction of platinum and cerium in the catalyst is 30-60 wt%.

2. The method for preparing the platinum-cerium alloy catalyst as described in claim 1, characterized in that, In S1, the platinum precursor salt is selected from one or more of chloroplatinic acid, platinum tetrachloride, dichlorodiammineplatinum, platinum acetylacetonate, and tetraammineplatinum; the cerium precursor salt is selected from one or more of cerium trichloride, cerium nitrate, cerium acetylacetonate, and cerium sulfate.

3. The method for preparing the platinum-cerium alloy catalyst as described in claim 1, characterized in that, In S2, the concentration of the carbon powder in solution B is 10-18.5 g / L.

4. The method for preparing the platinum-cerium alloy catalyst as described in claim 1, characterized in that, In S3, the alkaline solution is an aqueous solution of sodium hydroxide with a pH of 8.5-10.

5. The method for preparing the platinum-cerium alloy catalyst as described in claim 1, characterized in that, In S4, the parameters of the microwave are: frequency 2200-2600MHz, power 500-700W, single start time 55-65s, and single stop time 40-50s.

6. The method for preparing the platinum-cerium alloy catalyst as described in claim 1, characterized in that, S4 is followed by a step of washing and filtering with deionized water until the conductivity of the filtrate is less than 10 μS / cm, and drying at 110-130°C.

7. A platinum-cerium alloy catalyst prepared by the preparation method according to any one of claims 1-6.

8. The application of the platinum-cerium alloy catalyst of claim 7 in a fuel cell.

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