A method for preparing a small-size, high-loading platinum-based alloy catalyst

Abstract

The application discloses a preparation method of a small-size high-loading platinum-based alloy catalyst. The method comprises the following steps: (1) adding metal precursors and a template agent into mixed solvents respectively to obtain a mixed solution; (2) transferring the mixed solution into a tube furnace after drying, and firstly reacting at 200-600 DEG C for 1-5 h to obtain an intermediate product; then reacting at 300-700 DEG C for 0.5-5 h, and after washing, centrifuging and drying, different types of small-size high-loading platinum-based alloy catalysts are obtained. The application can effectively improve the nucleation rate of nanoparticles and increase the metal loading of the catalyst to 80-90%, and directly prepares small-size high-loading platinum-based alloy nanoparticle catalysts.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell catalyst technology, specifically relating to a method for preparing a small-sized, high-loading platinum-based alloy catalyst. Background Technology

[0002] Proton exchange membrane fuel cells (PEMFCs) are considered a promising sustainable energy conversion device due to their cleanliness, high efficiency, and high reliability. However, the slow reaction kinetics of the cathode oxygen reduction reaction (ORR) severely hinder the overall efficiency of PEMFCs. The widespread use of commercial platinum-carbon catalysts in the ORR is significantly hampered by the natural scarcity and high cost of platinum, which greatly limits the widespread application of PEMFCs.

[0003] Researchers have significantly improved the utilization rate of platinum atoms by synthesizing high-loading ultrafine platinum-based nanoparticle catalysts. However, ultrafine nanoparticles with high specific surface areas exhibit poor stability and are prone to dissolution and aggregation. Anchoring ultrafine nanoparticles on a support can effectively delay particle dissolution and diffusion, thereby improving catalyst stability. However, current support-anchored catalysts still suffer from problems such as low metal loading, metal particle aggregation, and uneven particle distribution. Therefore, designing a platinum-based nanoparticle catalyst with high loading, high activity, and high stability remains a challenge.

[0004] In the prior art, patent CN 110280240A, "A Carbon Nanosheet-Supported Noble Metal Nanoparticle Catalyst and Its Preparation Method and Application," mentions that an inorganic salt is used as a template, a noble metal chloride is used as a metal precursor, and sodium oleate is used as an additional carbon source. A composite catalyst is prepared by pyrolyzing and depositing noble metal nanoparticles on the carbon source. Although this synthesis method can effectively reduce the particle size of the catalyst and increase the metal loading, it still has several shortcomings: 1. It requires the additional supply of expensive commercial carbon source sodium oleate, which significantly increases the cost of catalyst preparation; 2. The synthesized catalyst is only a single pure noble metal catalyst, and the scarcity and high price of noble metals greatly hinder the commercialization process of this catalyst; 3. The effect of increasing the catalyst loading is not significant, and there are large differences between different embodiments, with metal loading ranging from 20% to 60%. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a method for preparing small-sized, high-load platinum-based alloy catalysts. This method first uses a metal acetylacetonate as a reaction precursor, eliminating the need for an additional carbon source. Transition metal elements such as iron, cobalt, nickel, copper, and zinc are successfully introduced into the synthesized catalyst, forming an alloy-type catalyst. This effectively reduces the amount of precious metals used while improving catalytic performance. Through a two-step heat treatment process under different atmospheres and temperatures, small-sized, high-load platinum-based alloy nanoparticle catalysts are directly prepared by pyrolysis.

[0006] The technical solution adopted in this invention is as follows:

[0007] A method for preparing a small-sized, high-loading platinum-based alloy catalyst, comprising the following steps:

[0008] (1) Add the metal precursor and template agent to the mixed solvent respectively, and sonicate for 15-30 min to obtain a mixed solution of metal precursor and template agent;

[0009] In this mixture, 0.01–0.20 mmol of platinum salt is added to every 20 mL of mixed solvent; the molar ratio of the metal precursor to the template agent in the mixed solvent is 1:50–250.

[0010] The mixed solvent is a mixture of anhydrous ethanol and deionized water, with a volume ratio of anhydrous ethanol to deionized water of 1:1 to 4.

[0011] (2) After drying the above mixed solution, transfer it to a tube furnace and heat it from room temperature to 200-600°C at a heating rate of 2-10°C / min. React it under a protective atmosphere for 1-5 hours to obtain an intermediate product. Then raise the reaction temperature to 300-700°C and continue the reaction under a reaction atmosphere for 0.5-5 hours. After cooling to room temperature, wash and centrifuge the product, collect the black product, and dry it to obtain different types of small-sized, high-load platinum-based alloy catalysts.

[0012] The metal precursor mentioned in step (1) is a platinum salt and a metal M salt. The salt is an acetylacetone salt, an acetate salt or a chloride salt, and the metal M is iron, cobalt, nickel, copper or zinc. The molar ratio of platinum to metal M is 1:0.2 to 2.

[0013] The template agent mentioned in step (1) is potassium chloride, potassium bromide, sodium chloride, sodium carbonate or sodium acetate;

[0014] In step (1), the preferred molar ratio of the metal precursor to the template agent is 1:200;

[0015] The protective atmosphere mentioned in step (2) is argon or nitrogen; the reaction atmosphere is a hydrogen-argon mixture with a hydrogen volume content of 3-10%, preferably with a hydrogen volume content of 5%.

[0016] In step (2), the mixed solution is dried by one of the following methods: drying in a forced-air oven, evaporation by stirring, or evaporation by rotary drying.

[0017] In step (2), the drying method for the black product is one of the following: oven drying, vacuum drying, or room temperature drying.

[0018] The platinum-based alloy catalyst described herein has coplanar carbon as its support and metal alloy nanoparticles with a particle size of 1–5 nm as its loading material, with a metal loading of 80%–90%.

[0019] The essential features of this invention are:

[0020] Using metallic acetylacetonate as a reaction precursor, the metallic acetylacetonate directly generates alloy nanoparticles supported on a carbon substrate through in-situ pyrolysis, eliminating the need for an additional carbon source and effectively reducing preparation costs. The introduction of transition metals such as iron, cobalt, nickel, copper, and zinc can effectively regulate the d-band center of Pt, enhancing catalytic activity while significantly reducing the amount of precious metals required. The two-step heat treatment process under different atmospheres can effectively improve the nucleation rate of nanoparticles and reduce particle size, contributing to the improvement of catalyst alloying degree and metal loading.

[0021] The beneficial effects of this invention are as follows:

[0022] 1. In terms of synthesis, this invention directly uses the metal acetylacetonate as the metal precursor, without the need for additional commercial carbon sources. The metal precursor is mixed with inorganic salt and then directly pyrolyzed to prepare a small-sized, high-load platinum-based alloy catalyst in a simple and efficient manner. This catalyst has many advantages such as high metal loading, small particle size, uniform distribution, simple preparation, and suitability for large-scale production.

[0023] 2. Regarding the structure and properties of the catalyst, (1) Compared with traditional platinum-based nanoparticle catalysts, this catalyst is mainly composed of graphene-like two-dimensional nanosheets with an average lateral size of 1 to 3 μm. It is ultrathin and contains abundant wrinkles, which can effectively enhance the interfacial charge transfer rate. Transmission electron microscopy images fully demonstrate that the catalyst is uniformly assembled from carbon-anchored ultrafine platinum-based alloy nanoparticles in different orientations. This structure can fully expose the surface defects of the nanoparticles and provide more active sites.

[0024] (2) Compared with pure noble metal nanoparticle catalysts, the alloying effect caused by the introduction of transition metals optimizes the electronic structure of platinum, shifts the d-band center of platinum atoms downward, weakens the adsorption of platinum with oxygen-containing intermediates, and improves catalytic activity while effectively reducing catalyst cost.

[0025] (3) A higher metal loading of the catalyst corresponds to a greater number of active sites. Thermogravimetric analysis results show that the metal loading of the synthesized catalyst is as high as 80-90%.

[0026] 3. In terms of performance, compared with commercial platinum-carbon catalysts, the small-sized, high-load platinum-based alloy catalysts prepared by this method exhibit excellent electrochemical performance. Taking the Pt3Ni3 catalyst as an example, its half-wave potential is 0.91V, which is much higher than that of commercial platinum-carbon catalysts. After 5000 cycles of the cycle stability test, the catalyst degradation is negligible, showing excellent stability. Attached Figure Description

[0027] Figure 1 Transmission electron microscopy (TEM) image of the small-sized, high-loading Pt3Ni3 catalyst prepared in Example 1;

[0028] Figure 2 The particle size distribution of the small-sized, high-loading Pt3Ni3 catalyst prepared in Example 1;

[0029] Figure 3 The powder X-ray diffraction pattern of the small-sized, high-loading Pt3Ni3 catalyst prepared in Example 1 is shown below.

[0030] Figure 4 Thermogravimetric analysis (TGA) spectra of the small-sized, high-loading Pt3Ni3 catalyst prepared in Example 1.

[0031] Figure 5 The polarization curve of the small-sized, high-loading Pt3Ni3 catalyst prepared in Example 1 is shown.

[0032] Figure 6 The transmission electron microscope (TEM) image of the small-sized, high-loading Pt3Fe3 catalyst prepared in Example 2;

[0033] Figure 7 The powder X-ray diffraction pattern of the small-sized, high-loading Pt3Fe3 catalyst prepared in Example 2 is shown below.

[0034] Figure 8 The transmission electron microscope (TEM) image of the small-sized, high-loading Pt3Co3 catalyst prepared in Example 3;

[0035] Figure 9 The powder X-ray diffraction pattern is the corresponding powder X-ray diffraction pattern of the small-sized, high-loading Pt3Co3 catalyst prepared in Example 3. Detailed Implementation

[0036] The technical solution of the present invention will be further described in detail below through specific embodiments. However, it should be noted that the following embodiments are only used to describe the content of the invention and do not constitute a limitation on the scope of protection of the present invention.

[0037] Example 1

[0038] A method for preparing a small-size, high-loading Pt3Ni3 catalyst includes the following steps:

[0039] 1) Preparation of mixed solution of metal precursor and template agent: At 25℃, 0.05 mmol platinum acetylacetonate, 0.05 mmol nickel acetylacetonate, and 10 mmol potassium chloride were dissolved in a mixed solvent consisting of 10 mL anhydrous ethanol and 10 mL deionized water. The mixture was sonicated for 30 min to fully dissolve the precursor, thus obtaining a mixed solution of metal precursor and template agent.

[0040] 2) Preparation of small-size, high-loading Pt3Ni3 catalyst: The mixed solution obtained in step 1) was evaporated to dryness using a rotary evaporator to obtain a mixed powder of metal precursor and template agent. The powder was placed in a tube furnace and heated from room temperature to 270°C at a heating rate of 10°C / min. After holding at this temperature for 2 hours under an argon atmosphere, the atmosphere was changed to a hydrogen-argon mixture with a hydrogen volume content of 5%. The temperature was then raised from 270°C to 350°C again at a heating rate of 10°C / min and held for 1 hour. The mixture was then cooled to room temperature and washed three times with a 1:1 volume ratio of anhydrous ethanol and deionized water. The black product was collected by centrifugation and dried at room temperature to obtain the final sample.

[0041] Figure 1 The image shows the transmission electron microscope (TEM) pattern of the small-sized, high-load Pt3Ni3 catalyst. The TEM pattern shows that the catalyst has an ultrathin two-dimensional structure with an average lateral size of 1-3 μm. The ultrathin structure contains abundant wrinkles, which can fully expose the catalytic sites and enhance the interfacial charge transfer efficiency.

[0042] Figure 2 The figure shows the particle size distribution of the small-sized, high-loading Pt3Ni3 catalyst. The particle size distribution shows that the average particle size of the catalyst is 3.23±0.06nm, which is characterized by its small size. The ultrafine particle size can effectively increase the specific surface area of ​​the catalyst, expose more active sites, and help improve the catalytic activity.

[0043] Figure 3The image shows the powder X-ray diffraction pattern of a small-sized, high-loading Pt3Ni3 catalyst. The X-ray diffraction pattern shows that the peak positions of each diffraction peak are consistent with the standard PDF card, indicating the successful synthesis of the Pt-Ni alloy. Compared with pure metal, the alloy can, on the one hand, shift the center position of the d-band of platinum downward through the strain effect, optimize the adsorption of intermediates, and improve catalytic activity; on the other hand, it can effectively reduce the amount of precious metals used and reduce the cost of the catalyst.

[0044] Figure 4 The thermogravimetric analysis (TGA) spectrum of the small-sized, high-load Pt3Ni3 catalyst is shown. The TGA spectrum shows that as the temperature increases, the carbon support is gradually oxidized and decomposed, and the remaining metal loading is 85.6075%. The Pt3Ni3 alloy catalyst synthesized by this method has a very high metal loading.

[0045] Figure 5 The polarization curves of the small-sized, high-loading Pt3Ni3 catalyst are shown. The polarization curves compare the initial polarization curves and the polarization curves after 5000 cycles of the Pt3Ni3 catalyst's stability test. All electrochemical experiments were conducted on a CHI 760E electrochemical workstation (Shanghai Chenhua) at room temperature using a conventional three-electrode system with a glassy carbon electrode (GCE, 5 mm diameter, 0.196 cm²). 2 The working electrode was a saturated calomel electrode, the reference electrode was a platinum sheet, and the counter electrode was a 0.1 M perchloric acid solution. The half-wave potential of the Pt3Ni3 catalyst was 0.91 V, which was much higher than that of commercial platinum-carbon. After 5000 cycles of cycling stability testing, its half-wave potential did not change significantly, demonstrating excellent stability.

[0046] Example 2

[0047] A method for preparing a small-sized, high-loading Pt3Fe3 catalyst includes the following steps:

[0048] 1) Preparation of mixed solution of metal precursor and template agent: At 25℃, 0.05 mmol of platinum acetylacetonate, 0.05 mmol of iron acetylacetonate and 10 mmol of potassium chloride were dissolved in a mixed solvent consisting of 10 mL of anhydrous ethanol and 10 mL of deionized water. The mixture was sonicated for 30 min to fully dissolve the precursor and obtain a mixed solution of metal precursor and template agent.

[0049] 2) Preparation of small-size, high-loading Pt3Fe3 catalyst: The mixed solution obtained in step 1) was evaporated to dryness using a rotary evaporator to obtain a mixed powder of metal precursor and template agent. The powder was placed in a tube furnace and heated from room temperature to 270°C at a heating rate of 10°C / min. After holding at this temperature for 2 hours under an argon atmosphere, the atmosphere was changed to a hydrogen-argon mixture with a hydrogen volume content of 5%. The temperature was then raised from 270°C to 350°C again at a heating rate of 10°C / min and held for 1 hour. The mixture was then cooled to room temperature and washed three times with a 1:1 volume ratio of anhydrous ethanol and deionized water. The black product was collected by centrifugation and dried at room temperature to obtain the final sample.

[0050] Figure 6 The image shows the transmission electron microscope (TEM) pattern of the small-sized, high-load Pt3Fe3 catalyst. The TEM pattern shows that the catalyst has an ultrathin two-dimensional structure with an average lateral size of 1-3 μm. The ultrathin structure contains abundant wrinkles, which can fully expose the catalytic sites, enhance the interfacial charge transfer efficiency, greatly improve the catalytic activity, and confirm the universality of the synthesis method.

[0051] Figure 7 The image shows the powder X-ray diffraction pattern of the small-sized, high-loading Pt3Fe3 catalyst. The X-ray diffraction pattern shows that the peak positions of each diffraction peak are consistent with the standard PDF card, indicating the successful synthesis of the Pt-Fe alloy. Compared with pure metal, the alloy can, on the one hand, shift the center position of the d-band of platinum downward through the strain effect, optimize the adsorption of intermediates, and improve catalytic activity; on the other hand, it can effectively reduce the amount of precious metals used and reduce the cost of the catalyst.

[0052] Example 3

[0053] A method for preparing a small-sized, high-loading Pt3Co3 catalyst includes the following steps:

[0054] 1) Preparation of mixed solution of metal precursor and template agent: At 25℃, 0.05 mmol of platinum acetylacetonate, 0.05 mmol of cobalt acetylacetonate and 10 mmol of potassium chloride were dissolved in a mixed solvent consisting of 10 mL of anhydrous ethanol and 10 mL of deionized water. The mixture was sonicated for 30 min to fully dissolve the precursor and obtain a mixed solution of metal precursor and template agent.

[0055] 2) Preparation of small-size, high-loading Pt3Co3 catalyst: The mixed solution obtained in step 1) was evaporated to dryness using a rotary evaporator to obtain a mixed powder of metal precursor and template agent. The powder was placed in a tube furnace and heated from room temperature to 270°C at a heating rate of 10°C / min. After holding at this temperature for 2 hours under an argon atmosphere, the atmosphere was changed to a hydrogen-argon mixture with a hydrogen volume content of 5%. The temperature was then raised from 270°C to 350°C again at a heating rate of 10°C / min and held for 1 hour. The mixture was then cooled to room temperature and washed three times with a 1:1 volume ratio of anhydrous ethanol and deionized water. The black product was collected by centrifugation and dried at room temperature to obtain the final sample.

[0056] Figure 8 The image shows the transmission electron microscope (TEM) pattern of the small-sized, high-load Pt3Co3 catalyst. The TEM pattern shows that the catalyst has an ultrathin two-dimensional structure with an average lateral size of 1-3 μm. The ultrathin structure contains abundant wrinkles, which can fully expose the catalytic sites, enhance the interfacial charge transfer efficiency, and greatly improve the catalytic activity, thus confirming the universality of the synthesis method.

[0057] Figure 9 The image shows the powder X-ray diffraction pattern of a small-sized, high-loading Pt3Co3 catalyst. The X-ray diffraction pattern shows that the peak positions of each diffraction peak are consistent with the standard PDF card, indicating the successful synthesis of the Pt-Co alloy. Compared with pure metal, the alloy can, on the one hand, shift the center position of the d-band of platinum downward through the strain effect, optimize the adsorption of intermediates, and improve catalytic activity; on the other hand, it can effectively reduce the amount of precious metals used and reduce the cost of the catalyst.

[0058] Example 4

[0059] A method for preparing a small-size, high-loading Pt3Ni1 catalyst includes the following steps:

[0060] 1) Preparation of mixed solution of metal precursor and template agent: At 25℃, 0.05 mmol platinum acetylacetonate, 0.016 mmol nickel acetylacetonate, and 10 mmol potassium chloride were dissolved in a mixed solvent consisting of 10 mL anhydrous ethanol and 10 mL deionized water. The mixture was sonicated for 30 min to fully dissolve the precursor, thus obtaining a mixed solution of metal precursor and template agent.

[0061] 2) Preparation of small-size, high-loading Pt3Ni1 catalyst: The mixed solution obtained in step 1) was evaporated to dryness using a rotary evaporator to obtain a mixed powder of metal precursor and template agent. The powder was placed in a tube furnace and heated from room temperature to 270°C at a heating rate of 10°C / min. After holding at this temperature for 2 hours under an argon atmosphere, the atmosphere was changed to a hydrogen-argon mixture with a hydrogen volume content of 5%. The temperature was then raised from 270°C to 350°C again at a heating rate of 10°C / min and held for 1 hour. The mixture was then cooled to room temperature and washed three times with a 1:1 volume ratio of anhydrous ethanol and deionized water. The black product was collected by centrifugation and dried at room temperature to obtain the final sample.

[0062] Example 5

[0063] A method for preparing a small-sized, high-loading Pt3Ni2 catalyst includes the following steps:

[0064] 1) Preparation of mixed solution of metal precursor and template agent: At 25℃, 0.05 mmol platinum acetylacetonate, 0.032 mmol nickel acetylacetonate and 10 mmol potassium chloride were dissolved in a mixed solvent consisting of 10 mL anhydrous ethanol and 10 mL deionized water. The mixture was sonicated for 30 min to fully dissolve the precursor and obtain a mixed solution of metal precursor and template agent.

[0065] 2) Preparation of small-size, high-loading Pt3Ni2 catalyst: The mixed solution obtained in step 1) was evaporated to dryness using a rotary evaporator to obtain a mixed powder of metal precursor and template agent. The powder was placed in a tube furnace and heated from room temperature to 270°C at a heating rate of 10°C / min. After holding at this temperature for 2 hours under an argon atmosphere, the atmosphere was changed to a hydrogen-argon mixture with a hydrogen volume content of 5%. The temperature was then raised from 270°C to 350°C again at a heating rate of 10°C / min and held for 1 hour. The mixture was then cooled to room temperature and washed three times with a 1:1 volume ratio of anhydrous ethanol and deionized water. The black product was collected by centrifugation and dried at room temperature to obtain the final sample.

[0066] Example 6

[0067] A method for preparing a small-sized, high-loading PtNiCo catalyst includes the following steps:

[0068] 1) Preparation of mixed solution of metal precursor and template agent: At 25℃, 0.05 mmol platinum acetylacetonate, 0.05 mmol nickel acetylacetonate, 0.05 mmol cobalt acetylacetonate and 10 mmol potassium chloride were dissolved in a mixed solvent consisting of 10 mL anhydrous ethanol and 10 mL deionized water. The mixture was sonicated for 30 min to fully dissolve the precursor, thus obtaining a mixed solution of metal precursor and template agent.

[0069] 2) Preparation of small-size, high-loading PtNiCo catalyst: The mixed solution obtained in step 1) was evaporated to dryness using a rotary evaporator to obtain a mixed powder of metal precursor and template agent. The powder was placed in a tube furnace and heated from room temperature to 270°C at a heating rate of 10°C / min. After holding at this temperature for 2 hours under an argon atmosphere, the atmosphere was changed to a hydrogen-argon mixture with a hydrogen volume content of 5%. The temperature was then raised from 270°C to 350°C again at a heating rate of 10°C / min and held for 1 hour. The mixture was then cooled to room temperature and washed three times with a 1:1 volume ratio of anhydrous ethanol and deionized water. The black product was collected by centrifugation and dried at room temperature to obtain the final sample.

[0070] Example 7

[0071] A method for preparing a small-sized, high-loading PtNiFe catalyst includes the following steps:

[0072] 1) Preparation of mixed solution of metal precursor and template agent: At 25℃, 0.05 mmol platinum acetylacetonate, 0.05 mmol nickel acetylacetonate, 0.05 mmol iron acetylacetonate and 10 mmol potassium chloride were dissolved in a mixed solvent consisting of 10 mL anhydrous ethanol and 10 mL deionized water. The mixture was sonicated for 30 min to fully dissolve the precursor, thus obtaining a mixed solution of metal precursor and template agent.

[0073] 2) Preparation of small-size, high-loading PtNiFe catalyst: The mixed solution obtained in step 1) was evaporated to dryness using a rotary evaporator to obtain a mixed powder of metal precursor and template agent. The powder was placed in a tube furnace and heated from room temperature to 270°C at a heating rate of 10°C / min. After holding at this temperature for 2 hours under an argon atmosphere, the atmosphere was changed to a hydrogen-argon mixture with a hydrogen volume content of 5%. The temperature was then raised from 270°C to 350°C again at a heating rate of 10°C / min and held for 1 hour. The mixture was then cooled to room temperature and washed three times with a 1:1 volume ratio of anhydrous ethanol and deionized water. The black product was collected by centrifugation and dried at room temperature to obtain the final sample.

[0074] Example 8

[0075] A method for preparing a small-sized, high-loading PtFeCo catalyst includes the following steps:

[0076] 1) Preparation of mixed solution of metal precursor and template agent: At 25℃, 0.05 mmol platinum acetylacetonate, 0.05 mmol iron acetylacetonate, 0.05 mmol cobalt acetylacetonate and 10 mmol potassium chloride were dissolved in a mixed solvent consisting of 10 mL anhydrous ethanol and 10 mL deionized water. The mixture was sonicated for 30 min to fully dissolve the precursor, thus obtaining a mixed solution of metal precursor and template agent.

[0077] 2) Preparation of small-size, high-loading PtFeCo catalyst: The mixed solution obtained in step 1) was evaporated to dryness using a rotary evaporator to obtain a mixed powder of metal precursor and template agent. The powder was placed in a tube furnace and heated from room temperature to 270°C at a heating rate of 10°C / min. After holding at this temperature for 2 hours under an argon atmosphere, the atmosphere was changed to a hydrogen-argon mixture with a hydrogen volume content of 5%. The temperature was then raised from 270°C to 350°C again at a heating rate of 10°C / min and held for 1 hour. The mixture was then cooled to room temperature and washed three times with a 1:1 volume ratio of anhydrous ethanol and deionized water. The black product was collected by centrifugation and dried at room temperature to obtain the final sample.

[0078] Example 9

[0079] A method for preparing a small-sized, high-loading PtFeCoNi catalyst includes the following steps:

[0080] 1) Preparation of a mixed solution of metal precursor and template agent: At 25℃, 0.05 mmol platinum acetylacetonate and 0.05 mmol iron acetylacetonate were mixed... 、 0.05 mmol cobalt acetylacetonate, 0.05 mmol nickel acetylacetonate, and 10 mmol potassium chloride were dissolved in a mixed solvent consisting of 10 mL anhydrous ethanol and 10 mL deionized water. The mixture was sonicated for 30 min to fully dissolve the precursor, resulting in a mixed solution of the metal precursor and the template agent.

[0081] 2) Preparation of small-size, high-loading PtFeCoNi catalyst: The mixed solution obtained in step 1) was evaporated to dryness using a rotary evaporator to obtain a mixed powder of metal precursor and template agent. The powder was placed in a tube furnace and heated from room temperature to 270°C at a heating rate of 10°C / min. After holding at this temperature for 2 hours under an argon atmosphere, the atmosphere was changed to a hydrogen-argon mixture with a hydrogen volume content of 5%. The temperature was then raised from 270°C to 350°C again at a heating rate of 10°C / min and held for 1 hour. The mixture was then cooled to room temperature and washed three times with a 1:1 volume ratio of anhydrous ethanol and deionized water. The black product was collected by centrifugation and dried at room temperature to obtain the final sample.

[0082] Example 10

[0083] A method for preparing a small-sized, high-loading PtFeCoNiZn catalyst includes the following steps:

[0084] 1) Preparation of mixed solution of metal precursor and template agent: At 25℃, 0.05 mmol platinum acetylacetonate, 0.05 mmol iron acetylacetonate, 0.05 mmol cobalt acetylacetonate, 0.05 mmol nickel acetylacetonate, 0.05 mmol zinc acetylacetonate and 12.5 mmol potassium chloride were dissolved in a mixed solvent consisting of 10 mL anhydrous ethanol and 10 mL deionized water. The solution was sonicated for 30 min to fully dissolve the precursors and obtain the mixed solution of metal precursor.

[0085] 2) Preparation of small-size, high-loading PtFeCoNiZn catalyst: The metal precursor solution obtained in step 1) was evaporated to dryness using a rotary evaporator to obtain a mixed powder of metal precursor and template agent. The powder was placed in a tube furnace and heated from room temperature to 270°C at a heating rate of 10°C / min. After holding at this temperature for 2 hours under an argon atmosphere, the atmosphere was changed to a hydrogen-argon mixture with a hydrogen volume content of 5%. The temperature was then raised from 270°C to 350°C again at a heating rate of 10°C / min and held for 1 hour. The mixture was then cooled to room temperature and washed three times with a 1:1 volume ratio of anhydrous ethanol and deionized water. The black product was collected by centrifugation and dried at room temperature to obtain the final sample.

[0086] Example 11

[0087] A method for preparing a small-size, high-loading PtFeCoNiCu catalyst includes the following steps:

[0088] 1) Preparation of mixed solution of metal precursor and template agent: At 25℃, 0.05 mmol platinum acetylacetonate, 0.05 mmol iron acetylacetonate, 0.05 mmol cobalt acetylacetonate, 0.05 mmol nickel acetylacetonate, 0.05 mmol copper acetylacetonate, and 12.5 mmol potassium chloride were dissolved in a mixed solvent consisting of 10 mL anhydrous ethanol and 10 mL deionized water. The solution was sonicated for 30 min to fully dissolve the precursors, thus obtaining the mixed solution of metal precursor.

[0089] 2) Preparation of small-size, high-loading PtFeCoNiCu catalyst: The metal precursor solution obtained in step 1) was evaporated to dryness using a rotary evaporator to obtain a mixed powder of metal precursor and template agent. The powder was placed in a tube furnace and heated from room temperature to 270°C at a heating rate of 10°C / min. After holding at this temperature for 2 hours under an argon atmosphere, the atmosphere was changed to a hydrogen-argon mixture with a hydrogen volume content of 5%. The temperature was then raised from 270°C to 350°C again at a heating rate of 10°C / min and held for 1 hour. The mixture was then cooled to room temperature and washed three times with a 1:1 volume ratio of anhydrous ethanol and deionized water. The black product was collected by centrifugation and dried at room temperature to obtain the final sample.

[0090] Example 12

[0091] A method for preparing a small-sized, high-loading Pt3Co3 catalyst includes the following steps:

[0092] 1) Preparation of mixed solution of metal precursor and template agent: At 25℃, 0.05 mmol of platinum acetylacetonate, 0.05 mmol of cobalt acetylacetonate and 10 mmol of potassium chloride were dissolved in a mixed solvent consisting of 10 mL of anhydrous ethanol and 10 mL of deionized water. The mixture was sonicated for 30 min to fully dissolve the precursor and obtain a mixed solution of metal precursor and template agent.

[0093] 2) Preparation of small-size, high-loading Pt3Co3 catalyst: The mixed solution obtained in step 1) was evaporated to dryness using a rotary evaporator to obtain a mixed powder of metal precursor and template agent. The powder was placed in a tube furnace and heated from room temperature to 350°C at a heating rate of 10°C / min. After holding at this temperature for 3 hours in a hydrogen-argon mixed atmosphere with a hydrogen volume content of 5%, it was cooled to room temperature and washed three times with a mixed solution of anhydrous ethanol and deionized water with a volume ratio of 1:1. The black product was collected by centrifugation and dried at room temperature to obtain the final sample.

[0094] Example 13

[0095] A method for preparing a small-sized, high-loading Pt3Co3 catalyst includes the following steps:

[0096] 1) Preparation of mixed solution of metal precursor and template agent: At 25℃, 0.05 mmol of platinum acetylacetonate, 0.05 mmol of cobalt acetylacetonate and 10 mmol of potassium chloride were dissolved in a mixed solvent consisting of 10 mL of anhydrous ethanol and 10 mL of deionized water. The mixture was sonicated for 30 min to fully dissolve the precursor and obtain a mixed solution of metal precursor and template agent.

[0097] 2) Preparation of small-size, high-loading Pt3Co3 catalyst: The mixed solution obtained in step 1) was evaporated to dryness using a rotary evaporator to obtain a mixed powder of metal precursor and template agent. The powder was placed in a tube furnace and heated from room temperature to 350°C at a heating rate of 10°C / min. After holding at this temperature for 3 hours under a nitrogen atmosphere, it was cooled to room temperature and washed three times with a mixed solution of anhydrous ethanol and deionized water in a volume ratio of 1:1. The black product was collected by centrifugation and dried at room temperature to obtain the final sample.

[0098] In summary, (1) this invention, through systematic design of the catalyst morphology and electronic structure, directly pyrolyzes and prepares a small-sized, high-loading platinum-based alloy catalyst. This catalyst has an ultra-thin two-dimensional feature, is highly curved and contains abundant wrinkles, which can effectively increase the specific surface area of ​​the catalyst. The catalyst is uniformly assembled from carbon-anchored ultrafine platinum-based alloy nanoparticles, with an ultra-high metal loading of 80-90%. The carbon generated by the in-situ pyrolysis of the acetylacetonate precursor can play a strong anchoring role for the alloy nanoparticles, which can effectively reduce the dissolution and aggregation of Pt while enhancing the utilization rate of Pt atoms, thereby improving the overall performance of the catalyst. This catalyst is a highly promising fuel cell catalyst with broad application prospects in the future energy industry.

[0099] (2) The catalyst preparation method adopted in this invention is simple, efficient and safe, and also has extremely high universality and industrialization potential. By controlling the type of precursor metal and reaction conditions, the efficient synthesis of different types of small-sized, high-load platinum-based alloy catalysts can be directly realized, which is of great value for the preparation of high-load, high-performance fuel cell catalysts.

[0100] Matters not covered in this invention are common knowledge.

Claims

1. A method for preparing a small-sized, high-loading platinum-based alloy catalyst, characterized in that: The method includes the following steps: (1) Add the metal precursor and template agent to the mixed solvent respectively, and sonicate for 15-30 min to obtain a mixed solution of metal precursor and template agent; The molar ratio of the metal precursor to the template agent is 1:50~250; 0.01~0.20 mmol of platinum salt is added to every 20 mL of mixed solvent; the metal precursor is a platinum salt and a metal M salt, wherein the salt is an acetylacetone salt, and the metal M is iron, cobalt, nickel, copper, or zinc metal, and the molar ratio of platinum to metal M is 1:0.2~2. The mixed solvent is anhydrous ethanol and deionized water; (2) After drying the above mixed solution, transfer it to a tube furnace and heat it from room temperature to 200-600°C at a heating rate of 2-10°C / min. React it under a protective atmosphere for 1-5 h to obtain an intermediate product. Then raise the reaction temperature to 300-700°C and continue the reaction under a reaction atmosphere for 0.5-5 h. After cooling to room temperature, wash and centrifuge the product, collect the black product, and dry it to obtain different types of small-sized, high-load platinum-based alloy catalysts. The protective atmosphere is argon or nitrogen; the reaction atmosphere is a hydrogen-argon mixture with a hydrogen volume content of 3-10%. In the mixed solvent described in step (1), the volume ratio of anhydrous ethanol to deionized water is 1:1~4; The template agent is potassium chloride, potassium bromide, sodium chloride, sodium carbonate, or sodium acetate; The platinum-based alloy catalyst is supported by coplanar carbon and loaded with metal alloy nanoparticles with a particle size of 1-5 nm, with a metal loading of 80%-90%.

2. The method for preparing the small-size, high-loading platinum-based alloy catalyst as described in claim 1, characterized in that: In step (1), the molar ratio of the metal precursor to the template agent is 1:

200.

3. The method for preparing the small-size, high-loading platinum-based alloy catalyst as described in claim 1, characterized in that: In step (2), the drying method of the mixed solution is one of drying in a blower oven, stirring and evaporating, or rotary evaporating; in step (2), the drying method of the black product is one of drying in a blower oven, vacuum drying, or air drying at room temperature.

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