Platinum-based high-entropy intermetallic compound and preparation method thereof, and application of platinum-based high-entropy intermetallic compound as hydrogen fuel cell cathode catalyst

Abstract

The invention discloses a platinum-based high-entropy intermetallic compound, a preparation method thereof and application of the platinum-based high-entropy intermetallic compound as a hydrogen fuel cell cathode catalyst, and belongs to the field of fuel cells. The preparation method comprises the following steps: S01, adding a platinum salt, at least five other metal salts and a nitrogen-rich organic compound into an organic solvent, and uniformly mixing to obtain a metal precursor mixed solution; s02, adding a carbon carrier into the metal precursor mixed solution, fully mixing, drying, and collecting to obtain a precursor; and S03, carrying out heat treatment on the dried precursor in a reducing atmosphere, and carrying out heat preservation treatment to obtain the platinum-based high-entropy intermetallic compound. The preparation method is simple, low in cost and good in repeatability, and the prepared catalyst has the advantages of uniform particle size, high oxygen reduction activity and the like, and has a good development prospect in the field of hydrogen fuel cell catalyst application.

Description

Technical Field

[0001] The present application relates to a platinum-based high-entropy intermetallic compound and a preparation method thereof, and its application as a cathode catalyst for a hydrogen fuel cell, belonging to the field of fuel cells. Background Art

[0002] As a clean and efficient secondary energy source, the development of hydrogen energy technology is crucial for upgrading my country's energy structure and shifting its current reliance on traditional fossil fuels. The proton exchange membrane fuel cell (PEMFC), a highly efficient hydrogen-to-electricity energy conversion device, is a key application of hydrogen energy in the transportation sector.

[0003] The oxygen reduction reaction (ORR) at the cathode of PEMFCs is kinetically slow, typically requiring the use of the precious metal platinum (Pt) as a catalyst. However, Pt is scarce in the Earth's crust and is expensive, and the durability of pure Pt catalysts is poor, significantly limiting the commercialization of fuel cell vehicles. Consequently, the development of highly active and durable Pt-based alloy catalysts has attracted widespread attention.

[0004] By introducing other inexpensive metal elements to manipulate the electronic structure of surface platinum atoms, the intrinsic catalytic activity of platinum can be enhanced, thereby reducing catalyst costs. Early molecular dynamics simulations and polycrystalline bulk experiments have confirmed that Pt-transition metal alloys and Pt-lanthanide metal alloys are considered to be two types of binary alloy systems with high oxygen reduction activity. However, the Pt-transition metal alloy catalysts currently reported are mostly solid solution structures. Due to the low redox potential of the transition metals, they are easily leached from the alloy structure under fuel cell operation, ultimately severely compromising the catalyst life. The standard reduction potential of lanthanide metals (approximately -2.3 V) is much lower than that of Pt (approximately +1.19 V), making it difficult to achieve co-reduction of the two metals using common reducing agents in conventional wet synthesis. Therefore, there are still few reported methods for the chemical synthesis of Pt-lanthanide metal alloy catalysts.

[0005] Intermetallic compounds, which have recently been widely discussed, differ from solid solutions in that their lattice structure differs from that of their original constituents. Their ordered atomic structure facilitates the separation of active sites, and their electronic structure can be regulated, making them promising catalysts. However, current research on intermetallic catalysts has largely focused on binary alloys. High-entropy alloys, or multi-component alloys, are novel alloy materials composed of four or more metallic elements, exhibiting excellent mechanical, physical, and chemical properties. Furthermore, high-entropy alloys contain a wide variety of elements, enabling synergistic catalytic interactions between the multi-component metals, resulting in superior catalytic performance. Therefore, combining the advantages of intermetallic compounds and high-entropy alloys' chemical synergy could lead to the development of oxygen reduction catalysts with higher intrinsic activity for use in hydrogen fuel cells.

[0006] Compared to disordered solid solution structures, the high degree of order and strong interactions between the metal elements in intermetallic compounds are believed to stabilize the alloy structure and prevent the precipitation of metal components during fuel cell operation, effectively improving the catalyst's cycling stability under fuel cell operating conditions. Due to the large differences in physical properties between the individual metal components, such as atomic radius and reduction potential, catalysts prepared by conventional wet synthesis suffer from problems such as low lattice structure order and even phase separation, making it difficult to synthesize ordered high-entropy alloy nanoparticles with a single intermetallic compound phase. Therefore, preparing single-phase high-entropy intermetallic compound nanoparticles while controlling the catalyst particle size is a major challenge. Summary of the Invention

[0007] According to the first aspect of the present application, a method for preparing a platinum-based high-entropy intermetallic compound is provided. The method comprises first dispersing a metal precursor and a nitrogen-rich organic compound in a solvent, adding a conductive carrier, mixing, and drying. The dried precursor mixture is then heat-treated in a tube furnace under a reducing atmosphere to obtain the platinum-based high-entropy intermetallic compound. This method is simple, scalable, and has good universal applicability.

[0008] A method for preparing a platinum-based high-entropy intermetallic compound, the preparation method comprising: S01: adding platinum salt, at least five other metal salts, and a nitrogen-rich organic compound to an organic solvent, and mixing them uniformly to obtain a metal precursor mixed solution; S02: adding a carbon support to the metal precursor mixed solution, mixing thoroughly, drying, and collecting to obtain a precursor; S03: heat-treating the dried precursor in a reducing atmosphere and performing heat preservation treatment to obtain a platinum-based high-entropy intermetallic compound.

[0009] Optionally, in step S01, the platinum salt is selected from at least one of platinum chloride, chloroplatinic acid and platinum acetylacetonate; The other metal salts include salts of transition metal elements or salts of lanthanide metal elements; The transition metal element is selected from iron, cobalt, nickel, copper, manganese or zinc; The lanthanide metal element is selected from lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or lutetium; The salt of the transition metal element is selected from the chloride, nitrate or acetylacetonate corresponding to the transition metal element; The salt of the lanthanide metal element is selected from the chloride, nitrate or acetylacetonate corresponding to the lanthanide metal element.

[0010] Among them, the at least five other metal salts are preferably five other metal salts. When the other metal salts are salts of transition metal elements, salts corresponding to five different transition elements are selected, such as five different transition elements of iron, cobalt, nickel, copper and zinc. In this case, ferric chloride, cobalt chloride, nickel chloride, copper chloride and zinc chloride are selected. When the other metal salts are salts of lanthanide metal elements, salts corresponding to five different lanthanide metal elements are selected, such as five different lanthanide metal elements of cerium, samarium, gadolinium, terbium and dysprosium. In this case, cerium chloride, samarium chloride, gadolinium chloride, terbium chloride and dysprosium chloride are selected.

[0011] Optionally, the salt of the transition metal element includes an iron salt, a cobalt salt, a nickel salt, a copper salt, a manganese salt, and a zinc salt. The iron salt is at least one of ferric chloride, ferric nitrate, or ferric acetylacetonate; the cobalt salt is at least one of cobalt chloride, cobalt nitrate, or cobalt acetylacetonate; the nickel salt is at least one of nickel chloride, nickel nitrate, or nickel acetylacetonate; the copper salt is at least one of copper chloride, copper nitrate, or copper acetylacetonate; the manganese salt is at least one of manganese chloride, manganese nitrate, or manganese acetylacetonate; and the zinc salt is at least one of zinc chloride, zinc nitrate, or zinc acetylacetonate.

[0012] Optionally, the salt of the lanthanide metal element includes lanthanum salt, cerium salt, praseodymium salt, neodymium salt, samarium salt, europium salt, gadolinium salt, terbium salt, dysprosium salt, holmium salt, erbium salt, thulium salt, ytterbium salt, and lutetium salt. The lanthanum salt is at least one of lanthanum chloride, lanthanum nitrate, or lanthanum acetylacetonate; the cerium salt is at least one of cerium chloride, cerium nitrate, or cerium acetylacetonate; the praseodymium salt is at least one of praseodymium chloride, praseodymium nitrate, or praseodymium acetylacetonate; the neodymium salt is at least one of neodymium chloride, neodymium nitrate, or neodymium acetylacetonate; the samarium salt is at least one of samarium chloride, samarium nitrate, or samarium acetylacetonate; the europium salt is at least one of europium chloride, europium nitrate, or europium acetylacetonate; and the gadolinium salt is at least one of gadolinium chloride, gadolinium nitrate, or gadolinium acetylacetonate. The terbium salt is at least one of terbium chloride, terbium nitrate or terbium acetylacetonate, the dysprosium salt is at least one of dysprosium chloride, dysprosium nitrate or dysprosium acetylacetonate, the holmium salt is at least one of holmium chloride, holmium nitrate or holmium acetylacetonate, the erbium salt is at least one of erbium chloride, erbium nitrate or erbium acetylacetonate, the thulium salt is at least one of thulium chloride, thulium nitrate or thulium acetylacetonate, the ytterbium salt is at least one of ytterbium chloride, ytterbium nitrate or ytterbium acetylacetonate, and the lutetium salt is at least one of lutetium chloride, lutetium nitrate or lutetium acetylacetonate.

[0013] Optionally, in step S01, the molar ratio of the platinum salt to the sum of the at least five other metal salts is 1 to 5:1; At least five other metal salts are used in equal molar ratios; In the metal precursor mixed solution, the total concentration of the metal salt is 1-100 mM.

[0014] The molar ratio of at least five other metal salts is equal. Taking the salts of five transition metal elements as an example, their molar ratio is preferably 1:1:1:1:1; taking the salts of five lanthanide metal elements as an example, their molar ratio is preferably 1:1:1:1:1.

[0015] Optionally, the molar ratio of the platinum salt to the sum of the at least five other metal salts is selected from any value of 1:1, 2:1, 3:1, 4:1, 5:1, or any range therebetween.

[0016] Optionally, in the metal precursor mixed solution, the total concentration of the metal salt is selected from any value among 1mM, 5mM, 100mM, 20mM, 30mM, 40mM, 50mM, 60mM, 70mM, 80mM, 90mM, 100mM or any range between two values.

[0017] Optionally, in step S01, the nitrogen-rich organic compound is selected from at least one of cyanamide (CN2H2), dicyandiamide (C2N4H4), melamine (C3N6H6), and ethylenediamine (C2H8N2); The molar ratio of the nitrogen-rich organic compound to the platinum salt is 10-20:1.

[0018] Preferably, the nitrogen-rich organic compound is cyanamide (CN2H2).

[0019] Preferably, the molar ratio of the nitrogen-rich organic compound to the platinum salt is 15:1.

[0020] Optionally, the molar ratio of the nitrogen-rich organic compound to the platinum salt is selected from any value among 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1 or any range between two values.

[0021] In the present application, a nitrogen-rich organic compound is used as an additive and is fully mixed with a metal precursor. During the subsequent heat treatment process, all metal atoms are subjected to the strong complexation effect of the nitrogen bonds of the nitrogen-rich organic compound and are evenly distributed in the carbon-nitrogen network structure. After reaching the thermal decomposition temperature of the nitrogen-rich organic compound in a reducing atmosphere, platinum is preferentially reduced to metallic platinum nanoparticles. The platinum nanoparticles dispersed around the nitrogen-rich organic compound drive the remaining metal atoms and platinum nanoparticles to form a high-entropy solid solution alloy structure. After further heat preservation treatment, its disordered solid solution structure is transformed into an ordered intermetallic compound structure.

[0022] Optionally, in step S01, the organic solvent is a mixture of water and alcohol; The alcohol is selected from at least one of ethanol and isopropanol.

[0023] The volume ratio of water to alcohol is preferably 1:1.

[0024] Optionally, in step S02, the carbon support is selected from at least one of Vulcan XC72, Vulcan XC72R, Ketjen Black EC300, Ketjen Black EC600JD, Ketjen Black ECP600JD and Black Pearls 2000.

[0025] The carbon support is used as the conductive support, and Ketjen Black ECP600JD (KB600) is preferred.

[0026] Optionally, the mass ratio of the carbon support to the platinum in the platinum salt is 7:3.

[0027] Optionally, in step S03, the reducing atmosphere is a mixed atmosphere containing hydrogen and an inert gas; The inert gas is selected from at least one of nitrogen, argon or helium.

[0028] The volume ratio of hydrogen gas to inert gas is preferably 1:9.

[0029] Optionally, in step S03, the temperature of the heat treatment is 500-600° C., and the time of the heat treatment is 1-120 min.

[0030] Preferably, the temperature of the heat treatment is 600° C., and the time of the heat treatment is 60 minutes.

[0031] Optionally, the temperature of the heat treatment is selected from any value of 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C or any range between two values.

[0032] Optionally, the heat treatment time is selected from any value among 1 min, 5 min, 10 min, 20 min, 50 min, 60 min, 80 min, 100 min, 110 min, 120 min or any range value between two of them.

[0033] Optionally, the set temperature for heat treatment is reached by programmed temperature increase, and the heating rate is preferably 10° C. / min.

[0034] Optionally, the insulation temperature is 700-900° C., and the insulation time is 1-120 minutes.

[0035] Preferably, the insulation temperature is 800° C., and the insulation time is 120 minutes.

[0036] Optionally, the insulation temperature is selected from any value among 700℃, 720℃, 750℃, 780℃, 800℃, 820℃, 850℃, 880℃, 900℃ or any range between two values.

[0037] Optionally, the insulation time is selected from any value among 1 min, 5 min, 10 min, 20 min, 50 min, 60 min, 80 min, 100 min, 110 min, 120 min or any range value between two of them.

[0038] As a preferred embodiment, the method for preparing the platinum-based high entropy intermetallic compound comprises: S01: Prepare the precursor dispersion: add the precursor metal salts of the platinum source and other metal sources to the organic solvent in proportion and ultrasonically mix for at least 30 minutes, then add them to the nitrogen-rich organic compound in a certain proportion and ultrasonically mix for at least 30 minutes; S02: Add a conductive carrier to the precursor mixture obtained in step S01, stir magnetically for at least 120 minutes to fully mix, and then dry in a vacuum drying oven at 80°C for collection; S03: The dried precursor collected in step S02 is transferred to a crucible and placed in a tube furnace, introduced into a reducing atmosphere for temperature-raising heat treatment and heat preservation treatment, and naturally cooled to obtain a platinum-based high-entropy intermetallic compound.

[0039] The present application directly mixes a metal salt, a conductive carrier and a nitrogen-rich organic compound in direct solution and then dries it to obtain a metal precursor, without relying on the participation of stabilizers, organic ligands or metal-organic frameworks. The nitrogen bonds in the nitrogen-rich organic compound introduced in the present application can complex and distribute all metal atoms, so that all metal atoms can be reduced on the same platinum particle to first form a solid solution structure high entropy alloy with a lower degree of order, and then further heat preservation treatment to transform it into a more ordered intermetallic compound. It shows better electrochemical activity and cycle durability, and shows excellent battery performance in actual hydrogen fuel cells.

[0040] According to a second aspect of the present application, a platinum-based high-entropy intermetallic compound is provided.

[0041] The platinum-based high-entropy intermetallic compound prepared by the preparation method described above.

[0042] This platinum-based high-entropy intermetallic compound remains relatively stable in harsh electrochemical environments. By using transition metals M (M=Fe, Co, Ni, Cu, Zn, etc.) or lanthanide metals Ln (Ln=Ce, Sm, Gd, Tb, Dy, etc.) to alloy with Pt, the multi-component metals play a synergistic role, regulating the electronic structure of the surface Pt atoms, improving the intrinsic activity of the catalyst, thereby reducing the amount of precious metals used and ultimately achieving cost reduction.

[0043] The resulting high-entropy alloy catalyst nanoparticles are uniformly loaded on a conductive carrier and exhibit a uniform size with no component segregation. They are single-phase intermetallic compounds free of other impurities, with an average particle size of less than 5 nanometers, meeting the requirements for hydrogen fuel cell cathode catalysts. They also possess advantages such as high oxygen reduction activity and hold great promise for their application in hydrogen fuel cell catalysts.

[0044] According to a third aspect of the present application, an application of a platinum-based high-entropy intermetallic compound is provided.

[0045] The application of the above-mentioned platinum-based high-entropy intermetallic compound as a cathode catalyst for hydrogen fuel cells.

[0046] The platinum-based high-entropy intermetallic compound described above is used as a cathode catalyst for the oxygen reduction reaction in hydrogen fuel cells, accelerating the oxygen reduction reaction at the cathode. Systematic electrochemical experiments demonstrated that the synthesized high-entropy intermetallic compound catalyst exhibited significantly superior oxygen reduction activity in the acidic electrolyte of 0.1 M perchloric acid compared to the commercial 40% Pt / C catalyst. It also exhibited excellent electrochemical stability, demonstrating promising potential for fuel cell applications.

[0047] The beneficial effects of this application include: The preparation method of the platinum-based high-entropy intermetallic compound provided in this application has the advantages of being simple, easy to achieve large-scale preparation, low cost, and good repeatability. The prepared high-entropy alloy catalyst nanoparticles are uniformly loaded on the conductive carrier, and are uniform in size without component segregation; they are single-phase intermetallic compounds without other impurities, and the average particle size is less than 5 nanometers, which meets the requirements of hydrogen fuel cell cathode catalysts. As a hydrogen fuel cell cathode catalyst for oxygen reduction reaction, it can accelerate the oxygen reduction reaction at the cathode. Systematic electrochemical experiments show that the synthesized high-entropy intermetallic compound catalyst has significantly better oxygen reduction activity in the acidic electrolyte 0.1 M perchloric acid than the commercial catalyst 40% Pt / C. It also has excellent electrochemical stability and good fuel cell application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is the X-ray diffraction pattern (XRD) of Pt-FeCoNiCuZn / KB600 in Example 1 of the present invention; Figure 2 is a high-resolution electron microscopy (HRTEM) image of Pt-FeCoNiCuZn / KB600 in Example 1 of the present invention; Figure 3 1 is a polarization curve diagram of Pt-FeCoNiCuZn / KB600 of Example 1 of the present invention and a commercial catalyst 40%Pt / C; Figure 4 1 is a bar graph comparing the area specific activity and mass specific activity of Pt-FeCoNiCuZn / KB600 of Example 1 of the present invention and the commercial catalyst 40%Pt / C; Figure 5 Figure 1 is an accelerated aging polarization curve of Pt-FeCoNiCuZn / KB600 of Example 1 of the present invention and a commercial catalyst 40%Pt / C, wherein Figure a corresponds to Pt-FeCoNiCuZn / KB600 and Figure b corresponds to the commercial catalyst 40%Pt / C; Figure 61 is a discharge curve and power density diagram of Pt-FeCoNiCuZn / KB600 of Example 1 of the present invention and a commercial catalyst 40% Pt / C measured in a hydrogen-air fuel cell at a relative atmospheric pressure of 100 kPa; Figure 7 is the X-ray diffraction pattern (XRD) of Pt-CeSmGdTbDy / KB600 in Example 2 of the present invention; Figure 8 is a high-resolution electron microscopy (HRTEM) image of Pt-CeSmGdTbDy / KB600 in Example 2 of the present invention; Figure 9 1 is a polarization curve diagram of Pt-CeSmGdTbDy / KB600 of Example 2 of the present invention and a commercial catalyst 40% Pt / C; Figure 10 4 is a bar graph comparing the area specific activity and mass specific activity of Pt-CeSmGdTbDy / KB600 of Example 2 of the present invention and the commercial catalyst 40% Pt / C; Figure 11 Figure 2 is an accelerated aging polarization curve of Pt-CeSmGdTbDy / KB600 of Example 2 of the present invention and a commercial catalyst 40% Pt / C, wherein Figure a corresponds to Pt-CeSmGdTbDy / KB600 and Figure b corresponds to a commercial catalyst 40% Pt / C; Figure 12 These are the discharge curves and power density diagrams of Pt-CeSmGdTbDy / KB600 of Example 2 of the present invention and the commercial catalyst 40% Pt / C measured in a hydrogen-air fuel cell at a relative atmospheric pressure of 100 kPa. DETAILED DESCRIPTION

[0049] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0050] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0051] Unless otherwise specified, conventional methods were used for testing, and instrument settings were those recommended by the manufacturer.

[0052] Among them, the conductive carrier KB600 is Ketjen Black ECP600JD.

[0053] The commercial catalyst 40% Pt / C was Johnson Matthey HiSPEC4000.

[0054] The analysis method in the examples of this application is as follows: Powder X-ray diffraction (XRD) analysis was carried out using an Empyrean S3 X-ray diffractometer with Cu Kα (λ = 1.5418 Å) as the radiation source at a scanning rate of 10° / min and a scanning range of 10° to 90°.

[0055] A Sigma 560 scanning electron microscope was used for SEM analysis, and a JEOL F200 field emission transmission electron microscope was used for TEM analysis of the samples.

[0056] The electrochemical tests were performed using a Chenhua CHI760E electrochemical workstation, and the fuel cell tests were performed using a Qunyi 850e fuel cell test bench.

[0057] Example 1 The preparation method of a platinum-based high-entropy intermetallic compound electrocatalyst includes first dispersing a metal precursor salt in an organic solvent, then sequentially adding a nitrogen-rich organic compound and a conductive carrier, mixing and drying to obtain a precursor, and then annealing the precursor to obtain a platinum-based high-entropy intermetallic compound electrocatalyst, wherein a nanoscale high alloy is supported on a conductive carrier KB600, and the high-entropy intermetallic compound includes the metal elements platinum, iron, cobalt, nickel, copper, and zinc. In this embodiment, the nanoscale high-entropy intermetallic compound is prepared by the following steps, which are as follows: S01: Prepare the precursor dispersion: add the precursor metal salts of six metal sources, namely chloroplatinic acid, ferric chloride, cobalt chloride, nickel chloride, copper chloride and zinc chloride, to an organic solvent at a molar ratio of 1:1 to the total molar ratio of platinum metal and other transition metals, and mix them ultrasonically for 30 minutes. The molar ratios of the other five transition metals are equal, and the organic solvent consists of water and ethanol at a volume ratio of 1:1. Cyanamide is then added to the precursor solution, with a molar ratio of cyanamide to platinum precursor of 15:1, and mixed ultrasonically for 30 minutes; wherein, the total concentration of the metal salts is 50 mM; S02: Add the corresponding amount of conductive carrier KB600 to the precursor mixture obtained in step S01 in a mass ratio of 7:3 between the conductive carrier KB600 and the platinum added to the platinum salt. After thorough mixing under magnetic stirring for 120 minutes, dry the mixture in a vacuum drying oven at 80°C and collect the mixture. S03: The dried precursor collected in step S02 was transferred to a crucible and placed in a tube furnace. Heat treatment was performed by introducing a mixed atmosphere of hydrogen and nitrogen at a volume ratio of 1:9 at a heating rate of 10°C / min to a temperature of 600°C for 60 minutes. The precursor was then held at 800°C for 120 minutes. After holding, the product was allowed to cool naturally to obtain a platinum-based high-entropy intermetallic compound catalyst.

[0058] Step S03 obtains the X-ray diffraction pattern (XRD) of Pt-FeCoNiCuZn / KB600 as shown in FIG. Figure 1 As shown in the figure, a face-centered cubic (fcc) structure of a single-phase intermetallic compound different from platinum is formed, which matches the standard card L10PtFe (JCPDS 26-1139), confirming that a single-phase intermetallic compound is formed.

[0059] The high resolution electron microscopy (HRTEM) image of Pt-FeCoNiCuZn / KB600 obtained in step S03 is as follows: Figure 2 As shown in the figure, the synthesized high entropy alloy nanoparticles are uniformly dispersed on the conductive carrier KB600. The catalyst particle size is uniform and the average particle size is around 1.9 nanometers.

[0060] The metal element content of the Pt-FeCoNiCuZn / KB600 obtained in step S03 was measured using inductively coupled plasma atomic emission spectroscopy (ICP-OES). The atomic percentages of the six metals were converted, as shown in Table 1. Pt accounts for the highest proportion of the total metal atoms, at 46.4%. The atomic percentages of the other five transition metals are comparable, ranging from 8.8% to 11.8%. This demonstrates that the atomic percentages in high-entropy intermetallic compounds can be adjusted by varying the amount of introduced metal salts.

[0061] Table 1 Atomic percentage of metals in Pt-FeCoNiCuZn / KB600

[0062] like Figure 3 As shown, with a saturated silver-silver chloride electrode as the reference electrode and a graphite carbon rod as the counter electrode, the polarization curves of Pt-FeCoNiCuZn / KB600 and commercial 40%Pt / C (Johnson Matthey HiSPEC4000) catalysts were tested in 0.1 M perchloric acid saturated with oxygen. It can be seen that the performance of the synthesized catalyst in 0.1 M perchloric acid acidic electrolyte is significantly better than that of the commercial catalyst 40%Pt / C. Its half-wave potential relative to the standard hydrogen electrode is 0.938V, while that of 40%Pt / C is 0.901V, proving that the material of this invention has great performance advantages as a cathode catalyst for hydrogen fuel cells.

[0063] like Figure 4The bar chart shows the platinum-normalized area specific activity (SA) and mass specific activity (MA) of Pt-FeCoNiCuZn / KB600 and a commercial catalyst (40% Pt / C) in 0.1 M perchloric acid electrolyte, using a saturated silver-silver chloride electrode as the reference electrode and a graphite carbon rod as the counter electrode. The platinum-normalized SA and MA of the material at a potential of 0.90 V are significantly higher than those of the commercial catalyst (40% Pt / C). The MA at 0.90 V is 1.96 A / mg Pt, 5.76 times that of the commercial 40% Pt / C (0.34 A / mg Pt). The SA at 0.90 V is 1.81 mA / cm², 2.92 times that of the commercial 40% Pt / C (0.34 mA / cm²). This demonstrates the excellent intrinsic activity and performance of the material (Pt-FeCoNiCuZn / KB600) obtained from this invention.

[0064] like Figure 5 As shown in a, the half-wave potential of Pt-FeCoNiCuZn / KB600 only decays by 2 mV after 30,000 cycles of accelerated aging. Figure 5 As shown in b, the half-wave potential of commercial Pt / C catalyst decays by 15 mV after 30,000 cycles of accelerated aging. Figure 5 a and Figure 5 b It can be seen that the present invention has good cyclic stability in 0.1M perchloric acid.

[0065] Figure 6 Pt-FeCoNiCuZn / KB600 and control commercial Pt / C catalyst (Johnson Matthey HiSPEC4000) were used as cathode catalysts, with a Pt metal loading of 0.2 mg Pt / cm 2 The anode used commercial 60% Pt / C (Johnson Matthey HiSPEC9100) as the catalyst, and the anode Pt metal loading was 0.05 mg Pt / cm 2 Discharge curves and power density plots measured in a hydrogen-air fuel cell at a relative atmospheric pressure of 100 kPa. A single fuel cell assembled using Pt-FeCoNiCuZn / KB600 and commercial Pt / C as cathode catalysts achieved power densities of 1.0 and 0.7 watts / square centimeter, respectively, at 0.65 V, with maximum power densities of 1.43 and 1.18 watts / square centimeter, respectively. This demonstrates that hydrogen-air fuel cells constructed with the materials of this invention exhibit superior performance compared to commercial Pt / C catalysts.

[0066] Example 2 In step S01 of this embodiment, the metal salts used in preparing the precursor dispersion are replaced with chloroplatinic acid, cerium chloride, samarium chloride, gadolinium chloride, terbium chloride, and dysprosium chloride. The precursor metal salts of the six metal sources are added to an organic solvent at a molar ratio of 5:1 to the sum of platinum metal and the other five lanthanide metals. The remaining steps are the same as in Example 1, thereby obtaining a nanoscale high-entropy intermetallic compound Pt-CeSmGdTbDy / KB600.

[0067] The X-ray diffraction pattern (XRD) of Pt-CeSmGdTbDy / KB600 is as follows: Figure 7 As shown, a close-packed hexagonal (hcp) structure different from that of a single-phase intermetallic compound of platinum is formed, which matches the standard card Pt5Sm (JCPDS 36-0079), confirming that a single-phase intermetallic compound is formed.

[0068] The obtained high resolution electron microscopy (HRTEM) image of Pt-CeSmGdTbDy / KB600 is as follows: Figure 8 As shown in the figure, the synthesized high entropy alloy nanoparticles are uniformly dispersed on the conductive carrier KB600. The catalyst particle size is uniform with an average particle size distribution of about 4.5 nanometers.

[0069] The metal element content of the resulting Pt-CeSmGdTbDy / KB600 was measured using inductively coupled plasma atomic emission spectroscopy (ICP-OES). The atomic percentages of the six metals were converted and shown in Table 2. Pt accounts for the highest proportion of the total metal atoms, at 81.58%. The atomic percentages of the other five lanthanide metals are comparable, ranging from 3.56% to 3.8%. This demonstrates that the atomic percentages in high-entropy intermetallic compounds can be adjusted by varying the amount of metal salt introduced.

[0070] Table 2 Atomic percentage of metals in Pt-CeSmGdTbDy / KB600

[0071] like Figure 9 As shown, with a saturated silver-silver chloride electrode as the reference electrode and a graphite carbon rod as the counter electrode, the polarization curves of Pt-CeSmGdTbDy / KB600 and commercial 40% Pt / C catalysts were tested in 0.1 M perchloric acid saturated with oxygen. It can be seen that the performance of the synthesized catalyst in 0.1 M perchloric acid acidic electrolyte is significantly better than that of the commercial catalyst 40% Pt / C. Its half-wave potential relative to the standard hydrogen electrode is 0.915 V, while that of 40% Pt / C is 0.901 V, proving that the material of this invention has great performance advantages as a cathode catalyst for hydrogen fuel cells.

[0072] like Figure 10 The bar graph shows a comparison of the platinum-normalized area specific activity (SA) and mass specific activity (MA) of Pt-CeSmGdTbDy / KB600 and the commercial catalyst 40% Pt / C in 0.1 M perchloric acid electrolyte, using a saturated silver-silver chloride electrode as the reference electrode and a graphite carbon rod as the counter electrode. The platinum-normalized SA and MA of the material at a potential of 0.90 V are significantly higher than those of the commercial catalyst 40% Pt / C. The MA at 0.90 V is 0.796 A / mg Pt, 2.34 times that of the commercial 40% Pt / C (0.34 A / mg Pt). The SA at 0.90 V is 1.4 mA / cm², 2.26 times that of the commercial 40% Pt / C (0.618 mA / cm²). This demonstrates the excellent intrinsic activity of the material (Pt-CeSmGdTbDy / KB600) obtained by this invention.

[0073] like Figure 11 As shown in a, the half-wave potential of Pt-CeSmGdTbDy / KB600 only decays by 6 mV after 30,000 cycles of accelerated aging. Figure 11 As shown in b, the half-wave potential of commercial Pt / C catalyst decays by 15 mV after 30,000 cycles of accelerated aging. Figure 11 a and Figure 11 b It can be seen that the present invention has good cyclic stability in 0.1M perchloric acid.

[0074] Figure 12 Pt-CeSmGdTbDy / KB600 and control commercial Pt / C catalyst (Johnson Matthey HiSPEC4000) were used as cathode catalysts, with a Pt metal loading of 0.2 mg Pt / cm 2 The anode used commercial 60% Pt / C (Johnson Matthey HiSPEC9100) as the catalyst, and the anode Pt metal loading was 0.05 mg Pt / cm 2 Discharge curves and power density plots measured in a hydrogen-air fuel cell at a relative atmospheric pressure of 100 kPa. A single fuel cell assembled using Pt-CeSmGdTbDy / KB600 and commercial Pt / C as cathode catalysts achieved power densities of 0.96 and 0.7 watts / square centimeter, respectively, at 0.65 V, with maximum power densities of 1.32 and 1.18 watts / square centimeter, respectively. This demonstrates that hydrogen-air fuel cells constructed with the present material exhibit superior performance compared to commercial Pt / C catalysts.

[0075] Therefore, the present invention utilizes the aforementioned preparation method to produce platinum-based high-entropy intermetallic compound catalysts with uniform particle size and high oxygen reduction activity. The preparation method of the present invention is simple, easily scalable, and universally applicable. Compared to the widely reported disordered high-entropy alloy solid solution structures, the present method can achieve a variety of platinum-based ordered high-entropy intermetallic compounds with superior structural stability and effective control of the various metal components. This method is expected to provide new insights into the search for superior platinum-based hydrogen fuel cell catalysts.

[0076] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a platinum-based high-entropy intermetallic compound, characterized in that: The preparation method comprises: S01: adding platinum salt, at least five other metal salts, and a nitrogen-rich organic compound to an organic solvent, and mixing them uniformly to obtain a metal precursor mixed solution; S02: adding a carbon support to the metal precursor mixed solution, mixing thoroughly, drying, and collecting to obtain a precursor; S03: heat-treating the dried precursor in a reducing atmosphere and performing heat preservation treatment to obtain a platinum-based high-entropy intermetallic compound.

2. The preparation method according to claim 1, characterized in that In step S01, the platinum salt is selected from at least one of platinum chloride, chloroplatinic acid and platinum acetylacetonate; The other metal salts include salts of transition metal elements or salts of lanthanide metal elements; The transition metal element is selected from iron, cobalt, nickel, copper, manganese or zinc; The lanthanide metal element is selected from lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or lutetium; The salt of the transition metal element is selected from the chloride, nitrate or acetylacetonate corresponding to the transition metal element; The salt of the lanthanide metal element is selected from the chloride, nitrate or acetylacetonate corresponding to the lanthanide metal element.

3. The preparation method according to claim 1, characterized in that In step S01, the molar ratio of the platinum salt to the sum of the at least five other metal salts is 1 to 5:1; At least five other metal salts are used in equal molar ratios; In the metal precursor mixed solution, the total concentration of the metal salt is 1-100 mM.

4. The preparation method according to claim 1, characterized in that In step S01, the nitrogen-rich organic compound is selected from at least one of cyanamide, dicyandiamide, melamine, and ethylenediamine; The molar ratio of the nitrogen-rich organic compound to the platinum salt is 10-20:

1.

5. The preparation method according to claim 1, characterized in that In step S01, the organic solvent is a mixture of water and alcohol; The alcohol is selected from at least one of ethanol and isopropanol.

6. The preparation method according to claim 1, characterized in that In step S02, the carbon support is selected from at least one of VulcanXC72, Vulcan XC72R, Ketjen Black EC300, Ketjen Black EC600JD, Ketjen BlackECP600JD and Black Pearls 2000.

7. The preparation method according to claim 1, characterized in that In step S03, the reducing atmosphere is a mixed atmosphere containing hydrogen and an inert gas; The inert gas is selected from at least one of nitrogen, argon or helium.

8. The preparation method according to claim 1, characterized in that In step S03, the heat treatment temperature is 500-600° C., and the heat treatment time is 1-120 min; The insulation temperature is 700-900° C., and the insulation time is 1-120 minutes.

9. A platinum-based high-entropy intermetallic compound prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the platinum-based high entropy intermetallic compound according to claim 9 as a cathode catalyst for a hydrogen fuel cell.

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