Platinum-based high-entropy alloy catalyst for hydrogen fuel cell, working electrode and preparation method of platinum-based high-entropy alloy catalyst
Platinum-based high-entropy alloy catalysts and working electrodes were prepared by liquid-phase synthesis, which solved the problem of insufficient efficiency of existing catalysts and achieved high activity and stable catalytic effect, meeting the high performance requirements of hydrogen fuel cells.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-14
- Publication Date
- 2026-04-10
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing platinum-based catalysts are not efficient enough in hydrogen fuel cells. Although high-entropy alloy catalysts have improved the redox reaction in hydrogen fuel cells, they still need to be further improved to meet market demands.
A liquid-phase synthesis method was used to react platinum salt, niobium salt, yttrium salt, tantalum salt, and ruthenium salt with a conductive powder support in acetylacetone to form a homogeneous metal acetylacetone complex. After thermal decomposition, a high-entropy alloy catalyst was formed, and the working electrode was prepared in a perfluorosulfonic acid membrane solution.
Precise control and atomic-level mixing of platinum-based high-entropy alloy catalysts were achieved, improving catalytic activity and stability, meeting the demand for low-platinum cost reduction, and enhancing the electrochemical performance of hydrogen fuel cells.
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Figure CN121839728A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of hydrogen fuel cell catalyst technology, and in particular to a platinum-based high-entropy alloy catalyst, working electrode and preparation method thereof for hydrogen fuel cells. Background Technology
[0002] A hydrogen fuel cell is a device that directly and efficiently converts the chemical energy of hydrogen and oxygen into electrical energy. The most commonly used catalysts in hydrogen fuel cells are platinum-based catalysts.
[0003] Traditionally, it is believed that too many types of doped metals may lead to disorder of active sites and reduce catalytic efficiency. Therefore, traditional platinum-based catalysts usually use 1-2 doped metals, such as pure platinum black, platinum carbon (Pt / C), or alloys formed by platinum and 1-2 metals (such as Pt-Co, Pt-Ni, etc.). Although these can adjust the electronic structure of platinum to a certain extent and improve its activity or stability, their catalytic efficiency is not strong enough.
[0004] High-entropy alloys are alloys formed from five or more metals in equal or approximately equal amounts. As a novel material, the "high-entropy" characteristic of high-entropy alloys is manifested in atomic-scale chemical and topological disorder, i.e., a highly disordered atomic arrangement. This disordered state endows high-entropy alloys with unique performance advantages. Currently, some high-entropy alloys have shown better catalytic performance in the redox reactions of hydrogen fuel cells compared to traditional platinum-based catalysts using one or two doped metals. However, further improvements are needed to meet increasingly demanding market requirements. Summary of the Invention
[0005] Given that some high-entropy alloys have shown good catalytic performance in the redox reaction of hydrogen fuel cells, but further improvements are needed to meet increasingly demanding market requirements, this application proposes a platinum-based high-entropy alloy catalyst, working electrode, and preparation method for hydrogen fuel cells.
[0006] In the first aspect, this application proposes a method for preparing a platinum-based high-entropy alloy catalyst for hydrogen fuel cells, and adopts the following technical solution.
[0007] A method for preparing a platinum-based high-entropy alloy catalyst for hydrogen fuel cells, the method comprising: Platinum salt, niobium salt, yttrium salt, tantalum salt, ruthenium salt, and conductive powder support are added to acetylacetone and heated to 60-80°C. This allows the platinum salt, niobium salt, yttrium salt, tantalum salt, and ruthenium salt to be converted into their respective metal acetylacetone complexes and dissolved in the acetylacetone solvent. After the reaction is complete, the acetylacetone solvent is evaporated, and the residue is washed and dried to obtain a precursor powder. The precursor powder is then heated to 600-800°C to decompose the acetylacetone in the metal acetylacetone complexes and alloy the various metal elements, thus obtaining the platinum-based high-entropy alloy catalyst.
[0008] By employing the above technical solution, all different metal salts are converted into acetylacetone complexes and dissolved in the same solvent, achieving uniform mixing of multiple metal precursors at the molecular / atomic level. This is a crucial prerequisite for forming truly high-entropy alloys rather than simple metal mixtures or core-shell structures, greatly promoting subsequent alloying processes. All reactants are in the same liquid phase, avoiding the inhomogeneities of traditional solid-state mixing methods and ensuring a high degree of consistency in the chemical composition of the final product. Combining the "precursor synthesis" and "dissolution" steps simplifies the operation and improves preparation efficiency and reproducibility. Acetylacetone acts as both a complex for the metal ions and a solvent for the complexes, forming a molecularly homogeneous mixed solution. This ensures that each metal ion is uniformly dispersed in the solution, and the powder obtained after solvent evaporation has a composition ratio highly consistent with the feed ratio, achieving precise control over the final catalyst chemical composition. The conductive powder carrier (e.g., carbon black) is also uniformly dispersed in this solution. The precursor powder obtained is a molecularly homogeneous mixture. During the subsequent thermal decomposition at 600–800 °C, metal atoms can nucleate and grow very uniformly, greatly promoting the formation of a nanoscale homogeneous alloy, which is crucial for catalyst activity. The conversion of the metal salt into the corresponding metal acetylacetone complex generates hydrogen chloride, which can be neutralized with an alkali (sodium carbonate) to promote the reaction. After the conversion reaction is complete, excess acetylacetone and the generated water can be removed by rotary evaporation in a 50–70 °C water bath. The residue can be washed several times with a small amount of anhydrous ethanol or acetone to remove residual sodium salts (such as NaCl), and then thoroughly dried to obtain a molecularly homogeneous powder of the pentametallic acetylacetone complex.
[0009] A preferred embodiment of the preparation method of the platinum-based high-entropy alloy catalyst for hydrogen fuel cells is that the platinum salt is H2PtCl6, the niobium salt is NbCl5, the yttrium salt is YCl3, the tantalum salt is TaCl5, and the ruthenium salt is RuCl3.
[0010] By adopting the above technical solution, the types of salts for each metal are specifically defined. These chloride salts have high reactivity and readily react with acetylacetone to form corresponding complexes.
[0011] A preferred embodiment of the preparation method of the platinum-based high-entropy alloy catalyst for hydrogen fuel cells is that the molar ratio of the platinum salt, the niobium salt, the yttrium salt, the tantalum salt and the ruthenium salt is (0.9-1.1):(0.9-1.1):(0.9-1.1):(0.9-1.1):(0.9-1.1).
[0012] By adopting the above technical solution and controlling the molar ratio of each metal to be close to 1:1, favorable conditions are provided for the formation of high-entropy alloys. This high-entropy environment can effectively suppress metal segregation and improve the structural stability of the alloy.
[0013] A preferred embodiment of the preparation method of the platinum-based high-entropy alloy catalyst for hydrogen fuel cells is that the metal salt includes platinum salt, niobium salt, yttrium salt, tantalum salt and ruthenium salt, and the mass ratio of metal salt: conductive powder support: acetylacetone is 1: (5~10): (50~100).
[0014] By employing the above technical solution, excess acetylacetone serves as both a reactant and a solvent, ensuring that all metal salts are completely converted into acetylacetone complexes and avoiding the residue of unreacted salts. The excess solvent guarantees that the reaction system remains a homogeneous solution, which is beneficial for forming uniform precursors.
[0015] A preferred embodiment of the preparation method of the platinum-based high-entropy alloy catalyst for hydrogen fuel cells is that, during the conversion of platinum salts, niobium salts, yttrium salts, tantalum salts, and ruthenium salts into the corresponding metal acetylacetone complexes, a base is added to neutralize the generated acid.
[0016] By adopting the above technical solution, the process of converting metal salts into corresponding metal acetylacetone complexes will generate hydrogen chloride. Adding alkali (sodium carbonate) to neutralize the hydrogen chloride will promote the reaction.
[0017] A preferred embodiment of the preparation method of the platinum-based high-entropy alloy catalyst for hydrogen fuel cells is that the process of heating the precursor powder to 600-800°C includes: placing the precursor powder in a reducing atmosphere, first heating it to 180-220°C at a heating rate of 1-3°C / min, holding it at 180-220°C for 5-10 min, then heating it to 600-800°C at a heating rate of 5-10°C / min, and holding it at 600-800°C for 2-4 h.
[0018] By employing the above technical solution, a reducing atmosphere can effectively reduce metal oxides (intermediate products of thermal decomposition) to elemental metals and greatly promote the alloying process. The first stage, with a slow initial heating rate (1-3 °C / min), slowly removes residual solvents and water of crystallization from the powder, and causes the complex to slowly decompose, releasing some organic ligands, thus avoiding powder splashing or particle agglomeration caused by violent outgassing or rapid decomposition. The second stage, with a heating rate of 5-10 °C / min to 600-800 °C, rapidly decomposes the complex framework, forms metal-oxygen bonds, and begins to reduce to metal atoms under the action of the reducing atmosphere. In the third stage, at a temperature of 600-800 °C, the metal atoms gain sufficient energy in the solid for migration and interdiffusion. Because the precursor is a molecular-level mixture with extremely short interatomic diffusion distances, the alloying process can be completed through solid-state diffusion at temperatures far below its melting point, forming a high-entropy alloy phase.
[0019] Secondly, this application provides a platinum-based high-entropy alloy catalyst for hydrogen fuel cells, and adopts the following technical solution.
[0020] A platinum-based high-entropy alloy catalyst for hydrogen fuel cells is prepared according to the method for preparing the platinum-based high-entropy alloy catalyst for hydrogen fuel cells.
[0021] By adopting the above technical solution, the catalyst possesses a unique microstructure, excellent component uniformity, high dispersion, and thus excellent catalytic performance (high activity and high stability) endowed by the aforementioned specific method.
[0022] Thirdly, this application provides a method for preparing the working electrode, and adopts the following technical solution.
[0023] A method for preparing a working electrode, the method comprising: dispersing a platinum-based high-entropy alloy catalyst for hydrogen fuel cells in a mixture of perfluorosulfonic acid membrane solution and isopropanol to obtain ink; dropping the ink onto a glassy carbon electrode and spreading it out; and drying the ink to form a thin film on the surface of the glassy carbon electrode to obtain the working electrode.
[0024] By employing the above technical solution and using a perfluorosulfonic acid membrane solution as a binder, not only are the catalyst particles firmly bonded to the electrode, but a proton transport channel is also provided. Together with the conductive catalyst and the reactant gas in the pores, this forms a highly efficient three-phase reaction interface, which is the foundation for achieving high-performance catalytic reactions. Through standardized ink preparation and drop-coating processes, a working electrode with high reproducibility and a uniform catalyst layer can be prepared, thereby ensuring the accuracy and comparability of subsequent electrochemical test data.
[0025] In summary, the platinum-based high-entropy alloy catalyst, working electrode, and preparation method for hydrogen fuel cells disclosed in this application have the following beneficial effects: A platinum-based high-entropy alloy catalyst with precise composition, atomically homogeneous mixing, and structural stability was successfully prepared via an innovative, efficient, and controllable liquid-phase synthesis route. This catalyst exhibits high catalytic activity and high stability in hydrogen fuel cells, meeting the potential demand for low-platinum cost reduction. Attached Figure Description
[0026] Figure 1 This is a flowchart of the implementation process of Example 1.
[0027] Figure 2 This is a TEM image of the platinum-based high-entropy alloy catalyst from Example 1.
[0028] Figure 3 This is a TEM image of the platinum-based high-entropy alloy catalyst from Example 2.
[0029] Figure 4 In the electrochemical tests of the experimental examples, the CV curves of the electrodes prepared based on the catalysts of Example 1 or Comparative Example 1 were recorded at a scan rate of 50 mV / s.
[0030] Figure 5 In the electrochemical tests of the experimental examples, the HER reaction LSV curves of the electrodes prepared based on the catalysts of Example 1 or Comparative Example 1 were recorded at a scan rate of 10 mV / s. Detailed Implementation
[0031] The technical solutions in the embodiments are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the following embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Example 1
[0032] A method for preparing a platinum-based high-entropy alloy catalyst for hydrogen fuel cells, referenced Figure 1 Follow these steps.
[0033] In a nitrogen atmosphere, platinum salt (H₂PtCl₆), niobium salt (NbCl₅), yttrium salt (YCl₃), tantalum salt (TaCl₅), ruthenium salt (RuCl₃), and carbon black were added to acetylacetone and heated to 60°C for 4 hours. This process converted the platinum, niobium, yttrium, tantalum, and ruthenium salts into their corresponding metal acetylacetone complexes, which then dissolved in the acetylacetone solvent. The carbon black was dispersed in the acetylacetone solvent. During the conversion reaction, sodium carbonate was added to adjust the pH of the solution to neutral to neutralize the hydrogen chloride generated during the conversion reaction and promote its progress. The molar ratio of platinum, niobium, yttrium, tantalum, and ruthenium salts was 0.9:1.1:0.9:1.1:0.9. The metal salts, including platinum, niobium, yttrium, tantalum, and ruthenium salts, were present in a mass ratio of metal salt:carbon black:acetylacetone = 1:5:50.
[0034] After the conversion reaction was completed, the solution was evaporated in a 60°C water bath to remove acetylacetone and the water generated by neutralization. The residue was washed with anhydrous ethanol to remove salts and dried at 80°C to obtain precursor powder.
[0035] The precursor powder was placed in a reducing atmosphere containing 5% hydrogen and 95% nitrogen (volume fraction). The temperature was first increased to 180°C at a rate of 1°C / min and held at 180°C for 10 min. Then, the temperature was increased to 600°C at a rate of 5°C / min and held at 600°C for 4 h. This decomposed the acetylacetone in the metal acetylacetone complex, alloying the various metal elements. After cooling to room temperature, a platinum-based high-entropy alloy catalyst was obtained. Figure 2 The image shows a TEM image of the platinum-based high-entropy alloy catalyst, with an average particle size of 2.82 nm. Example 2
[0036] A method for preparing a platinum-based high-entropy alloy catalyst for hydrogen fuel cells, comprising the following steps.
[0037] In a nitrogen atmosphere, platinum salt (H₂PtCl₆), niobium salt (NbCl₅), yttrium salt (YCl₃), tantalum salt (TaCl₅), ruthenium salt (RuCl₃), and carbon black were added to acetylacetone and heated to 70°C for 4 hours. This process converted the platinum, niobium, yttrium, tantalum, and ruthenium salts into their corresponding metal acetylacetone complexes, which then dissolved in the acetylacetone solvent. The carbon black was dispersed in the acetylacetone solvent. During the conversion reaction, sodium carbonate was added to adjust the pH of the solution to neutral to neutralize the hydrogen chloride generated and promote the reaction. The molar ratio of platinum, niobium, yttrium, tantalum, and ruthenium salts was 1:1:1:1:1. The metal salts, including platinum, niobium, yttrium, tantalum, and ruthenium salts, were present in a mass ratio of metal salt:carbon black:acetylacetone = 1:7:70.
[0038] After the conversion reaction was completed, the solution was evaporated in a 60°C water bath to remove acetylacetone and the water generated by neutralization. The residue was washed with anhydrous ethanol to remove salts and dried at 80°C to obtain precursor powder.
[0039] The precursor powder was placed in a reducing atmosphere containing 5% hydrogen and 95% nitrogen (volume fraction). The temperature was first increased to 200℃ at a rate of 2℃ / min and held at 200℃ for 7 min. Then, the temperature was increased to 700℃ at a rate of 7℃ / min and held at 700℃ for 3 h. The acetylacetone in the metal acetylacetone complex was decomposed, and the various metal elements alloyed. After cooling to room temperature, a platinum-based high-entropy alloy catalyst was obtained. Figure 3 The image shows a TEM image of the platinum-based high-entropy alloy catalyst, with an average particle size of 2.74 nm. Example 3
[0040] A method for preparing a platinum-based high-entropy alloy catalyst for hydrogen fuel cells, comprising the following steps.
[0041] In a nitrogen atmosphere, platinum salt (H₂PtCl₆), niobium salt (NbCl₅), yttrium salt (YCl₃), tantalum salt (TaCl₅), ruthenium salt (RuCl₃), and carbon black were added to acetylacetone and heated to 80°C for 4 hours. This process converted the platinum, niobium, yttrium, tantalum, and ruthenium salts into their corresponding metal acetylacetone complexes, which then dissolved in the acetylacetone solvent. The carbon black was dispersed in the acetylacetone solvent. During the conversion reaction, sodium carbonate was added to adjust the pH of the solution to neutral to neutralize the hydrogen chloride generated and promote the reaction. The molar ratio of platinum, niobium, yttrium, tantalum, and ruthenium salts was 1.1:0.9:1.1:0.9:1.1. The metal salts, including platinum, niobium, yttrium, tantalum, and ruthenium salts, were present in a mass ratio of metal salt:carbon black:acetylacetone = 1:10:100.
[0042] After the conversion reaction was completed, the solution was evaporated in a 60°C water bath to remove acetylacetone and the water generated by neutralization. The residue was washed with anhydrous ethanol to remove salts and dried at 80°C to obtain precursor powder.
[0043] The precursor powder was placed in a reducing atmosphere containing 5% hydrogen and 95% nitrogen (volume fraction). The temperature was first increased to 220°C at a rate of 3°C / min and held at 220°C for 5 min. Then, the temperature was increased to 800°C at a rate of 10°C / min and held at 800°C for 2 h. The acetylacetone in the metal acetylacetone complex was decomposed, and the metal elements were alloyed. The mixture was then cooled to room temperature to obtain a platinum-based high-entropy alloy catalyst.
[0044] Comparative Example 1 A method for preparing a platinum-based alloy catalyst for hydrogen fuel cells. The only difference between this comparative example and Example 1 is the removal of niobium salt NbCl5. The preparation method of this comparative example is carried out according to the following steps.
[0045] In a nitrogen atmosphere, platinum salt (H₂PtCl₆), yttrium salt (YCl₃), tantalum salt (TaCl₅), ruthenium salt (RuCl₃), and carbon black were added to acetylacetone and heated to 60°C for 4 hours. This process converted the platinum, yttrium, tantalum, and ruthenium salts into their corresponding metal acetylacetone complexes, which then dissolved in the acetylacetone solvent. The carbon black was dispersed in the acetylacetone solvent. During the conversion reaction, sodium carbonate was added to adjust the pH of the solution to neutral to neutralize the hydrogen chloride generated and promote the reaction. The molar ratio of platinum, yttrium, tantalum, and ruthenium salts was 0.9:0.9:1.1:0.9. The metal salts, including platinum, yttrium, tantalum, and ruthenium salts, were present in a mass ratio of metal salt:carbon black:acetylacetone = 1:5:50.
[0046] After the conversion reaction was completed, the solution was evaporated in a 60°C water bath to remove acetylacetone and the water generated by neutralization. The residue was washed with anhydrous ethanol to remove salts and dried at 80°C to obtain precursor powder.
[0047] The precursor powder was placed in a reducing atmosphere containing 5% hydrogen and 95% nitrogen (volume fraction). The temperature was first increased to 180°C at a rate of 1°C / min and held at 180°C for 10 min. Then the temperature was increased to 600°C at a rate of 5°C / min and held at 600°C for 4 h. The acetylacetone in the metal acetylacetone complex was decomposed, and the metal elements were alloyed. The mixture was then cooled to room temperature to obtain a platinum-based alloy catalyst.
[0048] Comparative Example 2 A method for preparing a platinum-based alloy catalyst for hydrogen fuel cells. The only difference between this comparative example and Example 1 is the removal of yttrium salt YCl3. The preparation method of this comparative example is carried out according to the following steps.
[0049] In a nitrogen atmosphere, platinum salt (H₂PtCl₆), niobium salt (NbCl₅), tantalum salt (TaCl₅), ruthenium salt (RuCl₃), and carbon black were added to acetylacetone and heated to 60°C for 4 hours. This process converted the platinum, niobium, tantalum, and ruthenium salts into their corresponding metal acetylacetone complexes, which then dissolved in the acetylacetone solvent. The carbon black was dispersed in the acetylacetone solvent. During the conversion reaction, sodium carbonate was added to adjust the pH of the solution to neutral to neutralize the hydrogen chloride generated and promote the reaction. The molar ratio of platinum, niobium, tantalum, and ruthenium salts was 0.9:1.1:1.1:0.9. The metal salts, including platinum, niobium, tantalum, and ruthenium salts, were present in a mass ratio of metal salt:carbon black:acetylacetone = 1:5:50.
[0050] After the conversion reaction was completed, the solution was evaporated in a 60°C water bath to remove acetylacetone and the water generated by neutralization. The residue was washed with anhydrous ethanol to remove salts and dried at 80°C to obtain precursor powder.
[0051] The precursor powder was placed in a reducing atmosphere containing 5% hydrogen and 95% nitrogen (volume fraction). The temperature was first increased to 180°C at a rate of 1°C / min and held at 180°C for 10 min. Then the temperature was increased to 600°C at a rate of 5°C / min and held at 600°C for 4 h. The acetylacetone in the metal acetylacetone complex was decomposed, and the metal elements were alloyed. The mixture was then cooled to room temperature to obtain a platinum-based alloy catalyst.
[0052] Comparative Example 3 A method for preparing a platinum-based alloy catalyst for hydrogen fuel cells. The only difference between this comparative example and Example 1 is the removal of tantalum salt TaCl5. The preparation method of this comparative example is carried out according to the following steps.
[0053] In a nitrogen atmosphere, platinum salt (H₂PtCl₆), niobium salt (NbCl₅), yttrium salt (YCl₃), ruthenium salt (RuCl₃), and carbon black were added to acetylacetone and heated to 60°C for 4 hours. This process converted the platinum, niobium, yttrium, and ruthenium salts into their corresponding metal acetylacetone complexes, which then dissolved in the acetylacetone solvent. The carbon black was dispersed in the acetylacetone solvent. During the conversion reaction, sodium carbonate was added to adjust the pH of the solution to neutral to neutralize the hydrogen chloride generated and promote the reaction. The molar ratio of platinum, niobium, yttrium, and ruthenium salts was 0.9:1.1:0.9:0.9. The metal salts, including platinum, niobium, yttrium, and ruthenium salts, were present in a mass ratio of metal salt:carbon black:acetylacetone = 1:5:50.
[0054] After the conversion reaction was completed, the solution was evaporated in a 60°C water bath to remove acetylacetone and the water generated by neutralization. The residue was washed with anhydrous ethanol to remove salts and dried at 80°C to obtain precursor powder.
[0055] The precursor powder was placed in a reducing atmosphere containing 5% hydrogen and 95% nitrogen (volume fraction). The temperature was first increased to 180°C at a rate of 1°C / min and held at 180°C for 10 min. Then the temperature was increased to 600°C at a rate of 5°C / min and held at 600°C for 4 h. The acetylacetone in the metal acetylacetone complex was decomposed, and the metal elements were alloyed. The mixture was then cooled to room temperature to obtain a platinum-based alloy catalyst.
[0056] Comparative Example 4 A method for preparing a platinum-based alloy catalyst for hydrogen fuel cells. The only difference between this comparative example and Example 1 is the removal of ruthenium salt RuCl3. The preparation method of this comparative example is carried out according to the following steps.
[0057] In a nitrogen atmosphere, platinum salt (H₂PtCl₆), niobium salt (NbCl₅), yttrium salt (YCl₃), tantalum salt (TaCl₅), and carbon black were added to acetylacetone and heated to 60°C for 4 hours. This process converted the platinum, niobium, yttrium, and tantalum salts into their corresponding metal acetylacetone complexes, which then dissolved in the acetylacetone solvent. The carbon black was dispersed in the acetylacetone solvent. During the conversion reaction, sodium carbonate was added to adjust the pH of the solution to neutral to neutralize the hydrogen chloride generated and promote the reaction. The molar ratio of platinum, niobium, yttrium, and tantalum salts was 0.9:1.1:0.9:1.1. The metal salts, including platinum, niobium, yttrium, and tantalum salts, were present in a mass ratio of metal salt:carbon black:acetylacetone = 1:5:50.
[0058] After the conversion reaction was completed, the solution was evaporated in a 60°C water bath to remove acetylacetone and the water generated by neutralization. The residue was washed with anhydrous ethanol to remove salts and dried at 80°C to obtain precursor powder.
[0059] The precursor powder was placed in a reducing atmosphere containing 5% hydrogen and 95% nitrogen (volume fraction). The temperature was first increased to 180°C at a rate of 1°C / min and held at 180°C for 10 min. Then the temperature was increased to 600°C at a rate of 5°C / min and held at 600°C for 4 h. The acetylacetone in the metal acetylacetone complex was decomposed, and the metal elements were alloyed. The mixture was then cooled to room temperature to obtain a platinum-based alloy catalyst.
[0060] Comprehensive application example A method for preparing a working electrode involves taking the platinum-based high-entropy alloy catalysts prepared in Examples 1-3 and the platinum-based alloy catalysts prepared in Comparative Examples 1-4, and applying them as follows: The catalyst was dispersed in a mixture of perfluorosulfonic acid membrane solution (supplied by Krytox, model D520) and isopropanol, and sonicated for 30 min to obtain ink. 20 µL of this ink was dropped onto a glassy carbon electrode, spread out, and dried to form a thin film on the surface of the glassy carbon electrode, thus obtaining the working electrode. The ratio of catalyst:perfluorosulfonic acid membrane solution:isopropanol was 2 mg:1 mL:50 mL.
[0061] The above applications were conducted under the same conditions except for the catalyst, resulting in seven different working electrodes.
[0062] Test case Electrochemical testing: The main testing methods include cyclic voltammetry (CV) and linear sweep voltammetry (LSV). Electrocatalytic performance tests were conducted in 0.1M HClO4 electrolyte using a standard three-electrode system, with a graphite rod as the counter electrode and a standard reversible hydrogen electrode as the reference electrode for data acquisition. The electrochemically active area (ECSA) was measured by cyclic voltammetry (CV), in meters.2 / gPt, at a scan rate of 50mV / s, record the CV curves of the electrodes prepared based on the catalysts of Example 1 or Comparative Example 1 as follows: Figure 4 .
[0063] Hydrogen evolution reaction (HER): Nitrogen gas was passed through a 0.1 M HClO4 electrolyte for 30 min until saturation. Data was acquired using linear voltammetry (LSV) in the test range of 0.1 to -0.5 V (vs. RHE), at a scan rate of 10 mV / s and a rotation speed of 1600 rpm. Durability test: 10,000 cycles were performed under accelerated cyclic voltammetry (ADT) at 0.1 to -0.2 V (vs. RHE) and 100 mV / s. Overpotentials were measured in mV. The HER reaction LSV curves for electrodes prepared based on the catalysts of Example 1 or Comparative Example 1 are recorded as follows. Figure 5 .
[0064] Hydroxylation reaction (HOR): Hydrogen gas was passed through a 0.1 M HClO4 electrolyte for 30 min until saturation. Data was acquired using linear sweep voltammetry (LSV) in the test range of -0.05 to 0.4 V (vs. RHE) at a scan rate of 10 mV / s and rotation speeds of 400 rpm, 900 rpm, 1600 rpm, and 2500 rpm. Durability testing: Accelerated cyclic voltammetry (ADT) was conducted at -0.05 to 0.4 V (vs. RHE) and 100 mV / s for 10,000 cycles. The catalytic current density for the hydrogenation reaction (HOR) was measured in mA / cm². 2 .
[0065] Oxygen Reduction Reaction (ORR): First, nitrogen gas was passed through a 0.1 M HClO4 electrolyte for 30 min until saturation. Background data was acquired using linear voltammetry (LSV) in the test range of 0.05–1.2 V (vs. RHE) at a scan rate of 10 mV / s and a rotation speed of 0 R. Then, oxygen was passed through the electrolyte for 30 min until saturation. Background data was acquired again using LSV in the test range of 0.05–1.2 V (vs. RHE) at a scan rate of 10 mV / s and rotation speeds of 400 R, 900 R, 1600 R, and 2500 R. Durability Testing: 10,000 cycles were performed using accelerated cyclic voltammetry (ADT) at 0.6–1.0 V (vs. RHE) and 50 mV / s. The half-wave potential (E) of the oxygen reduction reaction (ORR) was measured. 1 / 2 ), the unit is mV.
[0066] The data obtained from the above tests of the seven working electrodes prepared by the comprehensive application example are shown in Table 1 below.
[0067] Table 1 Comparison of electrical performance test data for each working electrode Test Items Cyclic voltammetry (CV) scan Hydrogen evolution reaction (HER) Hydrogen oxidation reaction (HOR) Oxygen reduction reaction (ORR) Source of catalyst Electrochemically active surface area ECSA (m 2 / g Pt) Overpotential (mV) Catalytic reaction current density (mA / cm 2 ) Half-wave potential E 1 / 2 (mV)]]> Example 1 61.54 33 9.82 115.9 Example 2 67.91 31 10.51 124.5 Example 3 59.68 37 9.39 106.7 Comparative Example 1 35.84 53 6.35 83.6 Comparative Example 2 42.51 48 6.98 91.5 Comparative Example 3 38.92 50 6.62 86.2 Comparative Example 4 44.63 45 7.10 92.3 In Table 1, ECSA represents the total number of active sites available for the reaction. A larger ECSA means more catalytically active atoms are exposed on the surface, resulting in higher catalytic efficiency. Overpotential is the additional voltage (exceeding the theoretical voltage) required to drive a reaction. A smaller overpotential means less kinetic barrier to the reaction and higher intrinsic catalyst activity. A higher catalytic reaction current density indicates a faster reaction rate. A higher half-wave potential means that the current can reach half of the limiting current at a lower overpotential (i.e., a higher electrode potential). This indicates that the catalyst has high activity under low drive conditions. A higher half-wave potential can lead to a higher operating voltage for the fuel cell, resulting in higher power density and energy efficiency.
[0068] As shown in Table 1, the catalysts prepared in Examples 1-3, when supported on the working electrode, exhibit larger electrochemical active area, lower overpotential, higher catalytic reaction current density, and larger half-wave potential compared to the catalysts prepared in Comparative Examples 1-4. This indicates that the catalysts prepared in Examples 1-3, when supported on the working electrode, possess superior electrical performance. Therefore, the use of a five-metal alloy (platinum, niobium, yttrium, tantalum, and ruthenium) demonstrates high efficiency in catalyzing the redox reaction between hydrogen and oxygen. Supporting this catalyst on the electrode significantly enhances its electrical performance, thereby improving the electrical performance of the hydrogen fuel cell.
[0069] This application converts all five metal salts into acetylacetone complexes and dissolves them in the same acetylacetone solvent. Acetylacetone acts as both the metal ion complex and the solvent for the complex, achieving uniform mixing of multiple metal precursors at the molecular / atomic level. The powder obtained after solvent evaporation has a composition ratio highly consistent with the feed ratio, enabling precise control of the final catalyst chemical composition. During subsequent thermal decomposition, metal atoms can nucleate and grow very uniformly, greatly promoting the formation of nanoscale homogeneous alloys. The resulting platinum-based high-entropy alloy catalyst exhibits extremely strong catalytic activity in the redox reaction of hydrogen fuel cells.
[0070] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A method for preparing a platinum-based high-entropy alloy catalyst for hydrogen fuel cells, characterized in that, The preparation method includes: Platinum salt, niobium salt, yttrium salt, tantalum salt, ruthenium salt, and conductive powder support are added to acetylacetone and heated to 60-80°C. This allows the platinum salt, niobium salt, yttrium salt, tantalum salt, and ruthenium salt to be converted into their respective metal acetylacetone complexes and dissolved in the acetylacetone solvent. After the reaction is complete, the acetylacetone solvent is evaporated, and the residue is washed and dried to obtain a precursor powder. The precursor powder is then heated to 600-800°C to decompose the acetylacetone in the metal acetylacetone complexes and alloy the various metal elements, thus obtaining the platinum-based high-entropy alloy catalyst.
2. The method for preparing the platinum-based high-entropy alloy catalyst for hydrogen fuel cells according to claim 1, characterized in that, The platinum salt is H2PtCl6, the niobium salt is NbCl5, the yttrium salt is YCl3, the tantalum salt is TaCl5, and the ruthenium salt is RuCl3.
3. The method for preparing the platinum-based high-entropy alloy catalyst for hydrogen fuel cells according to claim 2, characterized in that, The molar ratio of the platinum salt, the niobium salt, the yttrium salt, the tantalum salt, and the ruthenium salt is (0.9-1.1):(0.9-1.1):(0.9-1.1):(0.9-1.1):(0.9-1.1).
4. The method for preparing the platinum-based high-entropy alloy catalyst for hydrogen fuel cells according to any one of claims 1-3, characterized in that, Metal salts include platinum salts, niobium salts, yttrium salts, tantalum salts, and ruthenium salts. The mass ratio of metal salt to conductive powder carrier to acetylacetone is 1:(5~10):(50~100).
5. The method for preparing the platinum-based high-entropy alloy catalyst for hydrogen fuel cells according to claim 1, characterized in that, In the process of converting platinum salts, niobium salts, yttrium salts, tantalum salts, and ruthenium salts into their corresponding metal acetylacetone complexes, a base is added to neutralize the acid produced.
6. The method for preparing the platinum-based high-entropy alloy catalyst for hydrogen fuel cells according to claim 1, characterized in that, The process of heating the precursor powder to 600-800°C includes: placing the precursor powder in a reducing atmosphere, first heating it to 180-220°C at a heating rate of 1-3°C / min, holding it at 180-220°C for 5-10 min, then heating it to 600-800°C at a heating rate of 5-10°C / min, and holding it at 600-800°C for 2-4 h.
7. A platinum-based high-entropy alloy catalyst for hydrogen fuel cells, characterized in that, The catalyst is prepared according to any one of claims 1-6.
8. A method for preparing a working electrode, characterized in that, The preparation method includes: dispersing the platinum-based high-entropy alloy catalyst for hydrogen fuel cells according to claim 7 in a mixture of perfluorosulfonic acid membrane solution and isopropanol to obtain ink; dropping the ink onto a glassy carbon electrode and spreading it out; and after the ink dries, forming a thin film on the surface of the glassy carbon electrode to obtain a working electrode.