A platinum nanoparticle-based in-situ embedded dispersion PtCo nanocluster catalyst and a preparation method thereof

Abstract

The application provides a platinum nanoparticle-based embedded dispersion PtCo nanocluster catalyst and a preparation method thereof, and relates to the technical fields of fuel cells and nanomaterials. The particle size of the platinum nanoparticles in the catalyst is 4 nm-10 nm, and the platinum nanoparticles are internally dispersed with PtCo nanoclusters with a size of 0.3 nm-0.5 nm, and the molar ratio of Pt to Co is 20:1-5:1. The preparation method of the catalyst comprises the following steps: dispersing carbon black and a water-soluble polymer in deionized water, adding copper salt, performing liquid nitrogen quenching, freeze-drying and first-stage low-temperature heat treatment in a reducing atmosphere to obtain carbon-supported copper; dispersing the carbon-supported copper in a water-alcohol solution, adding metal cobalt salt, and performing second-stage medium-temperature heat treatment in an inert protective atmosphere to obtain carbon-supported copper cobalt oxide; adding the carbon-supported copper cobalt oxide into a platinum salt solution, and performing third-stage high-temperature heat treatment in a reducing atmosphere to obtain the catalyst. The catalyst prepared by the application can effectively inhibit the elution of transition metals, thereby significantly improving the durability.

Description

Technical Field

[0001] This invention relates to the field of fuel cells and nanomaterials, specifically to a platinum nanoparticle-based in-cell embedded PtCo nanocluster catalyst and its preparation method. Background Technology

[0002] High platinum loading is one of the challenges hindering the large-scale commercialization of fuel cells, attributed to the low catalytic activity of existing platinum-carbon catalysts. Alloying with transition metals (such as Co, Mn, and Ni) can significantly enhance catalyst activity, increasing it by 2-3 times and reducing platinum usage in fuel cells by 50%. However, because fuel cells operate in acidic, high-potential, and oxidizing environments, transition metals in the platinum alloy gradually dissolve during prolonged operation. This leads to decreased catalyst activity and proton exchange membrane contamination, significantly reducing fuel cell lifespan. Therefore, improving the stability of platinum alloy catalysts is crucial.

[0003] The activity and durability of platinum alloy catalysts are directly related to the content and distribution of transition metals within the platinum alloy particles. Higher transition metal content generally results in higher catalyst activity; however, during prolonged operation, the performance of fuel cells significantly degrades due to the reduction in catalytic activity caused by transition metal dissolution and the substantial decrease in proton conductivity resulting from transition metals entering ionomers and proton exchange membranes. Therefore, improving the distribution of transition metals within the alloy particles and inhibiting their dissolution are effective ways to enhance the durability of platinum alloy catalysts.

[0004] In existing technologies, platinum alloy catalysts are either left untreated with acid washing to maintain their activity, or they are acid-washed in air. Without acid washing, the dissolution of alloy ions leads to contamination of the membrane electrode assembly (MEA), resulting in severe mass transfer losses. Furthermore, the entry of alloying elements into the membrane and resin can trigger Fenton reactions, generating free radicals that attack resin side chains, leading to resin and membrane degradation over time. Direct acid washing and dealloying in air, due to the oxidizing effect of air, creates pores in the alloy particles as alloying elements dissolve, often resulting in significant roughness. Over time, with further dissolution of internal transition metals, the alloy structure gradually collapses, leading to loss of activity. Therefore, developing a novel PtCo alloy structure and its distribution is crucial for improving the durability of alloy catalysts. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a platinum nanoparticle-based in-cell PtCo nanocluster catalyst and its preparation method.

[0006] The embodiments in this specification provide the following technical solutions: On the one hand, a catalyst with PtCo nanoclusters embedded in platinum nanoparticles as the main body is provided. The particle size of the platinum nanoparticles in the catalyst is 4 nm to 10 nm, and PtCo nanoclusters are dispersedly distributed inside the platinum nanoparticles. The size of the PtCo nanoclusters is 0.3 nm to 0.5 nm.

[0007] In some embodiments, the molar ratio of Pt to Co is 20:1 to 5:1.

[0008] On the other hand, a method for preparing a platinum nanoparticle-based in-cell PtCo nanocluster catalyst is provided, comprising the following steps: Preparation of S1 carbon-supported copper (Cu / C): Carbon black and a water-soluble polymer compound were dispersed together in deionized water and subjected to ultrasonic dispersion and continuous stirring to obtain dispersion A; copper salt was added to dispersion A and the reaction was continuously stirred to obtain mixed dispersion B; dispersion B was rapidly cooled in liquid nitrogen and freeze-dried to obtain solid powder C; C was subjected to a first-stage low-temperature heat treatment in a reducing atmosphere to obtain carbon-supported copper (Cu / C). Preparation of S2 carbon-supported copper cobalt oxide (CoOx@Cu / C): Carbon-supported copper (Cu / C) is dispersed in an aqueous alcohol solution, cobalt salt is added, the reaction is continuously stirred, and after drying and grinding, a mixture D is obtained. The mixture D is subjected to a second-stage medium-temperature heat treatment under an inert protective atmosphere to obtain carbon-supported copper cobalt oxide (CoOx@Cu / C) solid powder. Preparation of S3 platinum nanoparticle-based embedded dispersed PtCo nanocluster catalyst: Carbon-supported copper cobalt oxide (CoOx@Cu / C) solid powder was added to a platinum salt solution and stirred continuously. After filtration, washing, drying and grinding, solid powder E was obtained. Solid powder E was subjected to a third-stage high-temperature heat treatment in a reducing atmosphere and then cooled to obtain platinum nanoparticle-based embedded dispersed PtCo nanocluster catalyst.

[0009] In some embodiments, the water-soluble polymer compound in S1 is one of starch, carboxymethyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylic acid.

[0010] In some embodiments, the weight ratio of carbon black to water-soluble polymer in S1 is 100:1 to 1000:1; the mass fraction of Cu in carbon-supported copper (Cu / C) is 20wt% to 50wt%.

[0011] In some embodiments, the alcohol in S2 is isopropanol, and the water-to-alcohol ratio (mass ratio) is 1:1 to 10:1.

[0012] In some embodiments, the cobalt salt in S2 includes one of cobalt chloride and its hydrate, cobalt nitrate and its hydrate, cobalt acetate and its hydrate, and cobalt sulfate and its hydrate.

[0013] In some embodiments, the temperature range of the first stage low-temperature heat treatment in S1 is 150℃~300℃, the treatment time range is 1h~5h, and the reducing atmosphere is a 5% hydrogen-argon mixed atmosphere.

[0014] In some embodiments, the temperature range of the second stage of the S2 heat treatment is 300℃~500℃, the treatment time range is 0.5h~3h, and the inert protective atmosphere is an argon atmosphere.

[0015] In some embodiments, the temperature range of the third stage high-temperature heat treatment in S3 is 700℃~1000℃, the treatment time range is 1h~8h, and the reducing atmosphere is a 5% hydrogen-argon mixed atmosphere.

[0016] This invention employs a step-by-step construction strategy to ultimately form a unique structure in which PtCo nanoclusters (0.3-0.5 nm) are dispersed within platinum nanoparticles (4-10 nm). Unlike traditional surface alloys or simple mixtures of platinum and cobalt catalysts, the PtCo clusters are physically embedded in a platinum-rich shell, significantly reducing the direct contact between Co and acidic electrolytes, high potentials, and oxidizing environments. Even during long-term operation of the fuel cell, the cobalt dissolution pathway is effectively blocked, thereby greatly improving catalyst durability while suppressing Co dissolution. 2+ Contamination of the proton exchange membrane.

[0017] This invention employs liquid nitrogen rapid cooling combined with freeze-drying technology in step S1 to anchor the Cu precursor in situ and uniformly onto the carbon support surface, avoiding metal agglomeration caused by traditional drying and providing an ideal substrate for subsequent uniform deposition. In step S2, Cu assists in the uniform distribution of CoOx around Cu nanoparticles, forming CoOx@Cu / C. In step S3, Cu replaces Pt, dispersing CoOx on Pt nanoparticles. Heat treatment at high temperature then occurs, as Pt more readily migrates to the surface, encapsulating the CoOx. Further alloying then forms a structure where PtCo clusters are embedded within platinum particles. This method requires no complex templates or post-processing, exhibits stable and reproducible processes, and is easily scaled up for production.

[0018] Due to the synergistic catalytic effect of PtCo alloy, the catalyst of this invention exhibits higher mass activity in the oxygen reduction reaction than commercial Pt / C catalysts. At the same time, it can reduce the platinum loading in the membrane electrode, effectively alleviating the constraint of high platinum cost on the commercialization of fuel cells.

[0019] This invention can form a stable embedded structure without acid washing of the catalyst, avoiding the risk of pores and structural collapse on the particle surface caused by air acid washing. At the same time, it avoids the problem of Fenton reaction caused by the dissolution of alloying elements and damage to the membrane electrode when no acid washing is performed.

[0020] The beneficial effects of this invention are: This invention first loads nano-Cu onto carbon powder, then rapidly cools it with liquid nitrogen to fix the metal in situ and uniformly onto the carbon support, which is beneficial for obtaining uniformly distributed nanoparticles after subsequent reduction. Further, cobalt oxide is loaded onto Cu nanoparticles, and then Cu replaces Pt, allowing CoOx to disperse on the Pt nanoparticles. Heat treatment is then performed at high temperature; since Pt migrates more easily to the surface, it encapsulates the CoOx, followed by alloying. A closed platinum-rich shell forms on the surface, locking in the PtCo alloy composition beneath, greatly inhibiting the loss of metal cations. Therefore, the preparation method of this invention enables platinum alloys to possess higher durability. Attached Figure Description

[0021] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the PtCo nanocluster catalyst with platinum nanoparticles as the main body embedded in the body, prepared in Example 1 of this application; Figure 2 These are TEM images and elemental distribution diagrams of the PtCo nanocluster catalyst with platinum nanoparticles as the main body, which was prepared in Example 1 of this application. Detailed Implementation

[0023] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0024] It should be noted that, unless otherwise specified, the present invention does not specifically limit the source of the raw materials used in the following embodiments. Commercially available products or products prepared by conventional preparation methods that are well known to those skilled in the art can be used. Experimental methods that do not specify specific conditions are all conventional methods and conventional conditions well known in the art.

[0025] Example 1

[0026] In this embodiment, the platinum nanoparticles embedded with dispersed PtCo nanoclusters are used as the catalyst as follows: S1: 5.0 g of carbon black and 0.025 g of polyacrylic acid were dispersed in 100 mL of deionized water and ultrasonically dispersed and continuously stirred to obtain dispersion A; 0.375 g of anhydrous copper sulfate was added to dispersion A and continuously stirred to obtain mixed dispersion B; dispersion B was rapidly cooled in liquid nitrogen for 10 min and freeze-dried at -60 °C for 24 h in a freeze dryer to obtain solid powder C; C was subjected to the first stage of low-temperature heat treatment in a 5% hydrogen-argon mixed atmosphere at a temperature of 200 °C for 3 h to obtain carbon-supported copper (Cu / C). S2: Weigh 2.5g of carbon-supported copper (Cu / C) and disperse it in 150mL of a mixed solution of water and isopropanol (water:isopropanol mass ratio of 3:1). Add 0.5g of cobalt acetate and stir at room temperature for 2h at 200rpm. Filter and wash, dry under vacuum at 80℃ for 12h, grind to obtain mixture D. Perform a second-stage medium-temperature heat treatment on mixture D in an argon atmosphere at 450℃ for 2h to obtain carbon-supported copper cobalt oxide (CoOx@Cu / C) solid powder. S3: Weigh 1.0 carbon-supported copper cobalt oxide (CoOx@Cu / C) solid powder and add it to 100 mL of 1.25 wt% chloroplatinic acid solution. Stir continuously at 300 rpm for 6 h at room temperature. After filtration, washing, drying and grinding, solid powder E is obtained. Solid powder E is subjected to a third-stage high-temperature heat treatment in a 5% hydrogen-argon mixed atmosphere at 900℃ for 5 h. After cooling to room temperature, a PtCo nanocluster catalyst with platinum nanoparticles as the main body is obtained.

[0027] The prepared catalyst had a particle size of 4.8 nm. One g of catalyst was treated in 100 mL of 1 mol / L sulfuric acid at 85 °C for 48 h. ICP testing revealed that the Co dissolution rate was 15 ppm, meaning 15 μg of Co was dissolved from 1 gram of catalyst. In the three-electrode system, the loading was 20 μg / cm³. 2 At a working electrode with a scan rate of 50 mV / s and a voltage range of 0.6~0.95 V, after 30,000 accelerated durability tests, the catalyst's specific activity decreased from 0.320 A / mgPt@0.9 V to 0.309 A / mgPt@0.9 V, with a decay rate of 3.5%.

[0028] Example 2

[0029] In this embodiment, the platinum nanoparticles embedded with dispersed PtCo nanoclusters are used as the catalyst as follows: S1: 5.0 g of carbon black and 0.025 g of polyacrylic acid were dispersed in 100 mL of deionized water and ultrasonically dispersed and continuously stirred to obtain dispersion A; 0.375 g of anhydrous copper sulfate was added to dispersion A and continuously stirred to obtain mixed dispersion B; dispersion B was rapidly cooled in liquid nitrogen for 10 min and freeze-dried at -60 °C for 24 h in a freeze dryer to obtain solid powder C; C was subjected to the first stage of low-temperature heat treatment in a 5% hydrogen-argon mixed atmosphere at a temperature of 200 °C for 3 h to obtain carbon-supported copper (Cu / C). S2: Weigh 2.5g of carbon-supported copper (Cu / C) and disperse it in 150mL of a mixed solution of water and isopropanol (water:isopropanol mass ratio of 3:1). Add 0.5g of cobalt acetate and stir at room temperature for 2h at 200rpm. Filter and wash, dry under vacuum at 80℃ for 12h, grind to obtain mixture D. Perform a second-stage medium-temperature heat treatment on mixture D in an argon atmosphere at 450℃ for 2h to obtain carbon-supported copper cobalt oxide (CoOx@Cu / C) solid powder. S3: Weigh 1.0 carbon-supported copper cobalt oxide (CoOx@Cu / C) solid powder and add it to 100 mL of 1.25 wt% chloroplatinic acid solution. Stir continuously at 300 rpm for 6 h at room temperature. After filtration, washing, drying and grinding, solid powder E is obtained. Solid powder E is subjected to a third-stage high-temperature heat treatment in a 5% hydrogen-argon mixed atmosphere at 750℃ for 5 h. After cooling to room temperature, a PtCo nanocluster catalyst with platinum nanoparticles as the main body is obtained.

[0030] The prepared catalyst had a particle size of 3.9 nm. One g of catalyst was treated in 100 mL of 1 mol / L sulfuric acid at 85 °C for 48 h. ICP testing revealed that the Co dissolution rate was 33 ppm, meaning 33 μg of Co was dissolved from one gram of catalyst. In the three-electrode system, the loading was 20 μg / cm³. 2 At a working electrode with a scan rate of 50 mV / s and a voltage range of 0.6~0.95 V, after 30,000 accelerated durability tests, the catalyst's specific activity decreased from 0.245 A / mgPt@0.9 V to 0.229 A / mgPt@0.9 V, with a decay rate of 6.5%.

[0031] Example 3

[0032] In this embodiment, the platinum nanoparticles embedded with dispersed PtCo nanoclusters are used as the catalyst as follows: S1: 5.0 g of carbon black and 0.01 g of polyacrylic acid were dispersed in 100 mL of deionized water and ultrasonically dispersed and continuously stirred to obtain dispersion A; 0.375 g of anhydrous copper sulfate was added to dispersion A and continuously stirred to obtain mixed dispersion B; dispersion B was rapidly cooled in liquid nitrogen for 10 min and freeze-dried at -60 °C for 24 h in a freeze dryer to obtain solid powder C; C was subjected to the first stage of low-temperature heat treatment in a 5% hydrogen-argon mixed atmosphere at a temperature of 200 °C for 3 h to obtain carbon-supported copper (Cu / C). S2: Weigh 2.5g of carbon-supported copper (Cu / C) and disperse it in 150mL of a mixed solution of water and isopropanol (water:isopropanol mass ratio of 3:1). Add 0.5g of cobalt acetate and stir at room temperature for 2h at 200rpm. Filter and wash, dry under vacuum at 80℃ for 12h, grind to obtain mixture D. Perform a second-stage medium-temperature heat treatment on mixture D in an argon atmosphere at 450℃ for 2h to obtain carbon-supported copper cobalt oxide (CoOx@Cu / C) solid powder. S3: Weigh 1.0 carbon-supported copper cobalt oxide (CoOx@Cu / C) solid powder and add it to 100 mL of 1.25 wt% chloroplatinic acid solution. Stir continuously at 300 rpm for 6 h at room temperature. After filtration, washing, drying and grinding, solid powder E is obtained. Solid powder E is subjected to a third-stage high-temperature heat treatment in a 5% hydrogen-argon mixed atmosphere at 900℃ for 5 h. After cooling to room temperature, a PtCo nanocluster catalyst with platinum nanoparticles as the main body is obtained.

[0033] The prepared catalyst had a particle size of 5.4 nm. One g of catalyst was treated in 100 mL of 1 mol / L sulfuric acid at 85 °C for 48 h. ICP testing revealed that the Co dissolution rate was 25 ppm, meaning 25 μg of Co was dissolved from 1 gram of catalyst. In the three-electrode system, the loading was 20 μg / cm³. 2 At a working electrode with a scan rate of 50 mV / s and a voltage range of 0.6~0.95 V, after 30,000 accelerated durability tests, the catalyst's specific activity decreased from 0.266 A / mgPt@0.9 V to 0.252 A / mgPt@0.9 V, with a decay rate of 5.2%.

[0034] Example 4

[0035] In this embodiment, the platinum nanoparticles embedded with dispersed PtCo nanoclusters are used as the catalyst as follows: S1: 5.0 g of carbon black and 0.05 g of polyacrylic acid were dispersed in 100 mL of deionized water and ultrasonically dispersed and continuously stirred to obtain dispersion A; 0.375 g of anhydrous copper sulfate was added to dispersion A and continuously stirred to obtain mixed dispersion B; dispersion B was rapidly cooled in liquid nitrogen for 10 min and freeze-dried at -60 °C for 24 h in a freeze dryer to obtain solid powder C; C was subjected to the first stage of low-temperature heat treatment in a 5% hydrogen-argon mixed atmosphere at a temperature of 200 °C for 3 h to obtain carbon-supported copper (Cu / C). S2: Weigh 2.5g of carbon-supported copper (Cu / C) and disperse it in 150mL of a mixed solution of water and isopropanol (water:isopropanol mass ratio of 3:1). Add 0.5g of cobalt acetate and stir at room temperature for 2h at 200rpm. Filter and wash, dry under vacuum at 80℃ for 12h, grind to obtain mixture D. Perform a second-stage medium-temperature heat treatment on mixture D in an argon atmosphere at 450℃ for 2h to obtain carbon-supported copper cobalt oxide (CoOx@Cu / C) solid powder. S3: Weigh 1.0 carbon-supported copper cobalt oxide (CoOx@Cu / C) solid powder and add it to 100 mL of 1.25 wt% chloroplatinic acid solution. Stir continuously at 300 rpm for 6 h at room temperature. After filtration, washing, drying and grinding, solid powder E is obtained. Solid powder E is subjected to a third-stage high-temperature heat treatment in a 5% hydrogen-argon mixed atmosphere at 900℃ for 5 h. After cooling to room temperature, a PtCo nanocluster catalyst with platinum nanoparticles as the main body is obtained.

[0036] The prepared catalyst had a particle size of 4.6 nm. One g of catalyst was treated in 100 mL of 1 mol / L sulfuric acid at 85 °C for 48 h. ICP testing revealed that the Co dissolution rate was 18 ppm, meaning 18 μg of Co was dissolved from 1 gram of catalyst. In the three-electrode system, the loading was 20 μg / cm³. 2 At a working electrode with a scan rate of 50 mV / s and a voltage range of 0.6~0.95 V, after 30,000 accelerated durability tests, the catalyst's specific activity decreased from 0.297 A / mgPt@0.9 V to 0.282 A / mgPt@0.9 V, with a decay rate of 5.0%.

[0037] Example 5

[0038] In this embodiment, the platinum nanoparticles embedded with dispersed PtCo nanoclusters are used as the catalyst as follows: S1: 5.0 g of carbon black and 0.025 g of polyacrylic acid were dispersed in 100 mL of deionized water and ultrasonically dispersed and continuously stirred to obtain dispersion A; 0.375 g of anhydrous copper sulfate was added to dispersion A and continuously stirred to obtain mixed dispersion B; dispersion B was rapidly cooled in liquid nitrogen for 10 min and freeze-dried at -60 °C for 24 h in a freeze dryer to obtain solid powder C; C was subjected to the first stage of low-temperature heat treatment in a 5% hydrogen-argon mixed atmosphere at a temperature of 200 °C for 3 h to obtain carbon-supported copper (Cu / C). S2: Weigh 2.5g of carbon-supported copper (Cu / C) and disperse it in 150mL of a mixed solution of water and isopropanol (water:isopropanol mass ratio of 5:1). Add 0.5g of cobalt acetate and stir at room temperature for 2h at 200rpm. Filter and wash, dry under vacuum at 80℃ for 12h, grind to obtain mixture D. Perform a second-stage medium-temperature heat treatment on mixture D in an argon atmosphere at 450℃ for 2h to obtain carbon-supported copper cobalt oxide (CoOx@Cu / C) solid powder. S3: Weigh 1.0 carbon-supported copper cobalt oxide (CoOx@Cu / C) solid powder and add it to 100 mL of 1.25 wt% chloroplatinic acid solution. Stir continuously at 300 rpm for 6 h at room temperature. After filtration, washing, drying and grinding, solid powder E is obtained. Solid powder E is subjected to a third-stage high-temperature heat treatment in a 5% hydrogen-argon mixed atmosphere at 900℃ for 5 h. After cooling to room temperature, a PtCo nanocluster catalyst with platinum nanoparticles as the main body is obtained.

[0039] The prepared catalyst had a particle size of 4.9 nm. One g of catalyst was treated in 100 mL of 1 mol / L sulfuric acid at 85 °C for 48 h. ICP testing revealed that the Co dissolution rate was 17 ppm, meaning 17 μg of Co was dissolved from 1 gram of catalyst. In the three-electrode system, the loading was 20 μg / cm³. 2 At a working electrode with a scan rate of 50 mV / s and a voltage range of 0.6~0.95 V, after 30,000 accelerated durability tests, the catalyst's specific activity decreased from 0.317 A / mgPt@0.9 V to 0.303 A / mgPt@0.9 V, with a decay rate of 4.4%.

[0040] Comparative Example 1 The only difference from Example 1 is that water-soluble polyacrylic acid polymer was not added in S1; the other steps are the same.

[0041] The prepared catalyst had a particle size of 6.6 nm. One g of catalyst was treated in 100 mL of 1 mol / L sulfuric acid at 85 °C for 48 h. ICP testing revealed that the Co dissolution rate was 37 ppm, meaning 37 μg of Co was dissolved from one gram of catalyst. In the three-electrode system, the loading was 20 μg / cm³. 2 At a working electrode with a scan rate of 50 mV / s and a voltage range of 0.6~0.95 V, after 30,000 accelerated durability tests, the catalyst's specific activity decreased from 0.217 A / mgPt@0.9 V to 0.183 A / mgPt@0.9 V, with a decay rate of 15.7%.

[0042] Comparative Example 2 The only difference from Example 1 is that anhydrous copper sulfate is not added in S1, while the other conditions are the same.

[0043] The prepared catalyst had a particle size of 7.3 nm. One g of catalyst was treated in 100 mL of 1 mol / L sulfuric acid at 85 °C for 48 h. ICP testing revealed that the Co dissolution rate was 54 ppm, meaning 54 μg of Co was dissolved from one gram of catalyst. In the three-electrode system, the loading was 20 μg / cm³. 2 At a working electrode with a scan rate of 50 mV / s and a voltage range of 0.6~0.95 V, after 30,000 accelerated durability tests, the catalyst's specific activity decreased from 0.157 A / mgPt@0.9 V to 0.125 A / mgPt@0.9 V, with a decay rate of 20.4%.

[0044] Comparative Example 3 The only difference from Example 1 is that the heat treatment temperature in S3 is 550°C, while the other conditions are the same.

[0045] The prepared catalyst had a particle size of 4.2 nm. One g of catalyst was treated in 100 mL of 1 mol / L sulfuric acid at 85 °C for 48 h. ICP testing revealed that the Co dissolution rate was 42 ppm, meaning 42 μg of Co was dissolved from one gram of catalyst. In the three-electrode system, the loading was 20 μg / cm³. 2 At a working electrode with a scan rate of 50 mV / s and a voltage range of 0.6~0.95 V, after 30,000 accelerated durability tests, the catalyst's specific activity decreased from 0.233 A / mgPt@0.9 V to 0.215 A / mgPt@0.9 V, with a decay rate of 7.7%.

[0046] Table 1 below shows the test data on the size and durability of the PtCo nanoclusters embedded in platinum nanoparticles prepared in Examples 1-5 and Comparative Examples 1-3 of this application.

[0047] Table 1

[0048] Based on the data in Table 1, by comparing the Co ion dissolution and electrochemical durability of the catalysts prepared in each embodiment with those in the comparative example, it can be found that the catalysts prepared based on this application have lower Co ion dissolution rates and lower catalyst activity decay rates, indicating that the catalyst samples of the embodiments have higher stability and resistance to dissolution.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A catalyst with platinum nanoparticles as the main body and embedded dispersed PtCo nanoclusters, characterized in that, The catalyst contains platinum nanoparticles with a particle size of 4 nm to 10 nm, and PtCo nanoclusters with a size of 0.3 nm to 0.5 nm are dispersed inside the platinum nanoparticles.

2. The platinum nanoparticle-based in-cell PtCo nanocluster catalyst according to claim 1, characterized in that, The molar ratio of Pt to Co is 20:1 to 5:

1.

3. A method for preparing a platinum nanoparticle-based in-cell PtCo nanocluster catalyst as described in any one of claims 1 and 2, characterized in that, Includes the following steps: Preparation of S1 carbon-supported copper: Carbon black and water-soluble polymer compound were dispersed together in deionized water and ultrasonically dispersed and continuously stirred to obtain dispersion A; copper salt was added to dispersion A and the reaction was continuously stirred to obtain mixed dispersion B; dispersion B was rapidly cooled in liquid nitrogen and freeze-dried to obtain solid powder C; solid powder C was subjected to a first-stage low-temperature heat treatment in a reducing atmosphere to obtain carbon-supported copper. Preparation of S2 carbon-supported copper cobalt oxide: Carbon-supported copper is dispersed in an aqueous alcohol solution, metallic cobalt salt is added, the reaction is continuously stirred, and after drying and grinding, a mixture D is obtained. The mixture D is subjected to a second-stage medium-temperature heat treatment under an inert protective atmosphere to obtain carbon-supported copper cobalt oxide solid powder. Preparation of S3 platinum nanoparticle-based embedded dispersed PtCo nanocluster catalyst: Carbon-supported copper cobalt oxide solid powder was added to a platinum salt solution and stirred continuously. After filtration, washing, drying and grinding, solid powder E was obtained. Solid powder E was subjected to a third-stage high-temperature heat treatment in a reducing atmosphere and cooled to obtain platinum nanoparticle-based embedded dispersed PtCo nanocluster catalyst.

4. The preparation method of a platinum nanoparticle-based in-cell embedded PtCo nanocluster catalyst according to claim 3, characterized in that, The water-soluble polymer compound in S1 is one of starch, carboxymethyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylic acid.

5. The preparation method of a platinum nanoparticle-based in-cell embedded PtCo nanocluster catalyst according to claim 3, characterized in that, The weight ratio of carbon black to water-soluble polymer in S1 is 100:1 to 1000:1; the mass fraction of Cu in carbon-supported copper is 20wt% to 50wt%.

6. The preparation method of a platinum nanoparticle-based in-cell PtCo nanocluster catalyst according to claim 3, characterized in that, The alcohol in S2 is isopropanol, and the water-to-alcohol mass ratio is 1:1 to 10:

1.

7. The preparation method of a platinum nanoparticle-based in-cell PtCo nanocluster catalyst according to claim 3, characterized in that, The cobalt salt in S2 includes one of cobalt chloride and its hydrate, cobalt nitrate and its hydrate, cobalt acetate and its hydrate, and cobalt sulfate and its hydrate.

8. The preparation method of a platinum nanoparticle-based in-cell embedded PtCo nanocluster catalyst according to claim 3, characterized in that, The temperature range of the first stage of low-temperature heat treatment in S1 is 150℃~300℃, the treatment time range is 1h~5h, and the reducing atmosphere is a 5% hydrogen-argon mixed atmosphere.

9. The preparation method of a platinum nanoparticle-based in-cell PtCo nanocluster catalyst according to claim 3, characterized in that, The temperature range of the second stage of the S2 medium-temperature heat treatment is 300℃~500℃, the treatment time range is 0.5h~3h, and the inert protective atmosphere is argon atmosphere.

10. The preparation method of a platinum nanoparticle-based in-cell PtCo nanocluster catalyst according to claim 3, characterized in that, The temperature range of the third stage high-temperature heat treatment in S3 is 700℃~1000℃, the treatment time range is 1h~8h, and the reducing atmosphere is a 5% hydrogen-argon mixed atmosphere.

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