Platinum-based high-entropy intermetallic compound electrocatalyst and preparation method thereof

Abstract

The invention discloses a platinum-based high-entropy intermetallic compound electrocatalyst and a preparation method thereof, the electrocatalyst is carbon material loaded platinum-based high-entropy intermetallic compound nanoparticles, and comprises 1-6 of six metal elements of platinum, manganese, iron, cobalt, nickel, zinc and copper, and 1-3 of three metal elements of gallium, indium and tin; in the nano-particles, platinum atoms account for 40%-60% of atoms, the platinum atoms and other metal atoms are orderly and regularly arranged, and the phase structure is an L10 phase. The preparation method of the platinum-based high-entropy intermetallic compound electrocatalyst is simple in process, and the metal loading capacity can be effectively controlled. Due to the introduction of the low-melting-point gallium / indium / tin metal, the high-entropy intermetallic compound can be prepared at a relatively low temperature, the agglomeration / sintering phenomenon is effectively avoided, and the platinum-based high-entropy intermetallic compound electrocatalyst with uniform size and adjustable components can be obtained. The electrocatalyst can be used for a fuel cell cathode material, and has important significance for improving the performance of a fuel cell.

Description

Technical Field

[0001] The present invention belongs to the field of fuel cell catalysts, and particularly relates to a platinum-based high-entropy intermetallic compound electrocatalyst and a preparation method thereof. Background Art

[0002] It is very important to develop efficient catalysts to improve the operating efficiency of energy conversion devices. Among them, metallic platinum is the most common electrocatalyst for oxygen reduction reaction, alcohol oxidation reaction, hydrogen evolution reaction, etc. Constructing dual / triple metal alloys can regulate the electronic structure of (near) surface atoms through unique strain / ligand effects, thereby promoting the electrocatalytic performance of single-metal materials. However, the compositional range of atoms in the alloy is limited by the differences in crystal structure, atomic size, electronegativity, and electron concentration among different atoms in the metal catalyst, which in turn leads to limited regulation of the electronic structure and restricts the further optimization of the absorption / desorption ability of intermediates, making it difficult to maximize the catalytic activity. In order to further break the scaling relationship in electrocatalysis, it is necessary to achieve continuous regulation of the electronic structure on the surface of metal catalysts.

[0003] High-entropy alloys are a new type of alloy system constructed from five or more elements with atomic fractions between 5% and 35%. The continuous regulation of their component distribution is expected to break the barrier of continuous regulation of the electronic structure of traditional binary or ternary alloys, making the adsorption / desorption energy of reaction intermediates closer to the optimal value, and thus showing great potential in electrocatalysis. In addition, the atoms in intermetallic compounds are orderly distributed, which can provide a higher mixing enthalpy and stronger interatomic interaction, and thus exhibit stronger chemical stability. Combining the advantages of high-entropy alloys and intermetallic compounds to construct high-entropy intermetallic compounds can further enhance electrocatalytic activity and stability. Although the ordered structure is an important feature that distinguishes intermetallic compounds from disordered solid solution alloys, due to the fact that the number of constituent elements is more than the number of sublattices, the site occupancy in each sublattice of high-entropy intermetallic compounds is still random or nearly random. In order to overcome the ordering energy barrier of ordered intermetallic compounds, high-temperature heat treatment is usually required, which often causes sintering and aggregation of nanocrystals. In addition, the preparation of high-entropy intermetallic compounds also faces the problem of phase separation caused by high-temperature heat treatment. Summary of the Invention

[0004] The present invention aims to provide a platinum-based high-entropy intermetallic compound electrocatalyst and a preparation method thereof. The electrocatalyst is nano-particles with an ordered atomic structure supported on a carbon material, and the metal atoms in the nano-particles are orderly arranged to form an L10-phase intermetallic structure. Its preparation method is simple and controllable, and the relatively low heat treatment temperature effectively avoids the sintering and aggregation of nano-particles.

[0005] In the first aspect of the present invention, a multi-metal platinum-based alloy nanoparticle is provided. The nanoparticle has a disordered solid solution structure and contains at least five different metal elements including platinum. The other metal elements except platinum are selected from 1 to 6 of the six metal elements of manganese, iron, cobalt, nickel, copper, and zinc, and 1 to 3 of the three metal elements of gallium, indium, and tin.

[0006] Preferably, in the multi-metal platinum-based alloy nanoparticle, the atomic percentage of platinum atoms is 40% to 60%, most preferably 50%, and the remainder is other metal atoms. Among them, the atomic percentage of 1 to 3 of the three metal elements of gallium, indium, and tin is 5% to 35%.

[0007] Preferably, the size of the multi-metal platinum-based alloy nanoparticle is 3 to 5 nm.

[0008] In the second aspect of the present invention, a preparation method of the multi-metal platinum-based alloy nanoparticle described in the first aspect is provided. The preparation method includes the following steps:

[0009] Step a: Dissolve at least five metal precursor salts and a carbonyl compound reducing agent in oleylamine to form a homogeneous solution. The at least five metal precursor salts contain at least five different metal elements, and the at least five different metal elements refer to platinum, 1 to 6 of the six metal elements of manganese, iron, cobalt, nickel, copper, and zinc, and 1 to 3 of the three metal elements of gallium, indium, and tin;

[0010] Step b: Place the homogeneous solution formed in step a in an oil bath for a reduction reaction, and then naturally cool to room temperature to obtain a black colloidal solution;

[0011] Step c: Add ethanol to the black colloidal solution obtained in step b to obtain a precipitate. After centrifugal separation and washing with a cyclohexane / ethanol mixture, the multi-metal platinum-based alloy nanoparticle can be obtained.

[0012] Preferably, the metal precursor salts in step a are oil-soluble salts, and can be selected from platinum acetylacetonate, manganese acetylacetonate, iron acetylacetonate, cobalt acetylacetonate, nickel acetylacetonate, copper acetylacetonate, zinc acetylacetonate, gallium acetylacetonate, indium acetylacetonate, tin dichloride, etc.

[0013] Preferably, the carbonyl compound reducing agent in step a is preferably one or more of chromium hexacarbonyl, molybdenum hexacarbonyl, and tungsten hexacarbonyl.

[0014] Preferably, the concentration of the platinum precursor salt used in step a is 5 mmol / L, the concentration of other metal precursor salts is 0 to 5 mmol / L, and the total concentration of other metal precursor salts is 5 mmol / L. The concentration of the carbonyl compound reducing agent (such as molybdenum hexacarbonyl) is 5 to 25 mmol / L.

[0015] Preferably, in step b, the oil bath temperature is 180 - 220 °C, and the reduction reaction time is 6 - 15 hours.

[0016] Preferably, in step c, the addition amount of ethanol is 2 - 4 times the volume of the solution described in step a, the centrifugation speed is 7000 - 9500 rpm / min, and the volume ratio of cyclohexane / ethanol in the cyclohexane / ethanol mixture is 1 / 2 - 1 / 4.

[0017] The multi-metal platinum-based alloy nanoparticles prepared by the above method have uniform sizes, controllable compositions, and adjustable ratios of each metal element.

[0018] In the third aspect of the present invention, a platinum-based high-entropy intermetallic compound electrocatalyst is provided. The electrocatalyst is high-entropy intermetallic compound nanoparticles supported on a carbon carrier. The high-entropy intermetallic compound nanoparticles contain at least five different metal elements including platinum. The other metal elements except platinum are selected from 1 - 6 of the six metal elements of manganese, iron, cobalt, nickel, copper, and zinc, and 1 - 3 of the three metal elements of gallium, indium, and tin; the platinum atoms and other metal atoms in the high-entropy intermetallic compound nanoparticles are arranged in an orderly and regular manner, and the phase structure is the L10 phase.

[0019] Preferably, the carbon carrier is Vulcan XC-72 or Ketjenblack conductive carbon carrier. The mass percentage of the high-entropy intermetallic compound nanoparticles in the electrocatalyst to the carbon carrier is 5% - 40%.

[0020] Preferably, in the high-entropy intermetallic compound nanoparticles, the atomic percentage of platinum atoms is 40% - 60%, most preferably 50%, and the rest are other metal atoms. Among them, the atomic percentage of 1 - 3 of the three metal elements of gallium, indium, and tin is 5% - 35%.

[0021] Preferably, the size of the high-entropy intermetallic compound nanoparticles is 3 - 5 nm.

[0022] In the fourth aspect of the present invention, a preparation method of the platinum-based high-entropy intermetallic compound electrocatalyst described in the first aspect is provided. The preparation method includes the following steps:

[0023] Step d: Ultrasonically disperse the carbon carrier in ethanol to form a uniform carbon dispersion liquid. Disperse the multi-metal platinum-based alloy nanoparticles obtained in step c in cyclohexane, and drop them into the carbon dispersion liquid. After ultrasonic mixing, centrifuge and separate, wash with ethanol multiple times, and after drying, carbon-supported multi-metal platinum-based alloy nanoparticles can be obtained;

[0024] Step e: Calcinate the carbon-supported multi-metal platinum-based alloy nanoparticles obtained in step d in air to remove impurity molecules such as oleylamine;

[0025] Step f: Place the product obtained in step e in a reducing atmosphere and calcine it at 400 - 600 °C to obtain the platinum-based high-entropy intermetallic compound electrocatalyst.

[0026] Preferably, the carbon support in step d is Ketjen black or XC-72 conductive carbon support.

[0027] Preferably, the concentration of the carbon support in the homogeneous carbon dispersion liquid formed in step d is 0.5 mg / mL, and the mass percentage of the added multi-metal platinum-based alloy nanoparticles to the carbon support is 5% - 40%.

[0028] Preferably, the ultrasonic treatment in step d is carried out for 2 - 4 hours.

[0029] Preferably, the calcination temperature in step e in air is 220 - 240 °C, and the time is 2 - 4 hours.

[0030] Preferably, the reducing atmosphere in step f is 5% hydrogen-argon mixture (5% hydrogen and 95% argon), the most preferred calcination temperature is 500 - 600 °C, and the calcination time is 4 - 8 hours.

[0031] Due to the introduction of low-melting-point gallium, indium, and / or tin metals, the above preparation method provided by the present invention can prepare high-entropy intermetallic compounds at a relatively low temperature (400 - 600 °C), effectively avoiding the agglomeration and sintering phenomena caused by the traditional preparation of high-entropy intermetallic compounds, and obtaining a platinum-based high-entropy intermetallic compound electrocatalyst with uniform size and adjustable composition.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] (1) The present invention overcomes the kinetic barriers of multi-element mixing through a simple and mild wet chemical method, realizing the controllable preparation of multi-metal (five or more) platinum-based nanoparticles with uniform size.

[0034] (2) The platinum-based high-entropy intermetallic compound electrocatalyst prepared by the present invention has uniform size and adjustable composition. Due to the combination of multiple elements, the electronic structures of various metals are effectively regulated, which can not only improve the electrocatalytic activity but also improve the durability.

[0035] (3) The metal atoms in the platinum-based high-entropy intermetallic compound electrocatalyst prepared by the present invention are arranged orderly, showing strong interatomic interactions, providing strong structural stability, and contributing to improving the electrocatalytic activity and durability.

[0036] (4) The preparation method of the platinum-based high-entropy intermetallic compound electrocatalyst provided by the present invention has a simple process and can effectively control the metal loading to be applicable to different catalytic occasions.

[0037] (5) The preparation method of the platinum-based high-entropy intermetallic compound electrocatalyst provided by the present invention can prepare a series of five- to ten-element platinum-based high-entropy intermetallic compound electrocatalysts with controllable elemental composition and microstructure, and has high universality. Description of the Drawings

[0038] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the following description of the embodiments in conjunction with the drawings. It should be understood that these drawings only depict some embodiments disclosed according to the present invention, and are used to provide a further understanding of the present invention, constitute a part of this application, and should not be regarded as a limitation on the scope of the present invention.

[0039] Figure 1 Transmission electron microscope image of platinum-iron-cobalt-nickel-copper-tin alloy nanoparticles prepared in Example 1.

[0040] Figure 2 X-ray diffraction pattern of platinum-iron-cobalt-nickel-copper-tin alloy nanoparticles prepared in Example 1.

[0041] Figure 3 Transmission electron microscope image of platinum-iron-cobalt-nickel-copper-tin intermetallic compound electrocatalyst prepared in Example 1.

[0042] Figure 4 X-ray diffraction pattern of platinum-iron-cobalt-nickel-copper-tin intermetallic compound electrocatalyst prepared in Example 1.

[0043] Figure 5 Aberration-corrected scanning transmission electron microscope image of platinum-iron-cobalt-nickel-copper-tin intermetallic compound electrocatalyst prepared in Example 1;

[0044] Figure 6 Elemental mapping diagram of platinum-iron-cobalt-nickel-copper-tin intermetallic compound electrocatalyst prepared in Example 1.

[0045] Figure 7 Transmission electron microscope image of platinum-iron-cobalt-nickel-zinc-tin intermetallic compound electrocatalyst prepared in Example 2.

[0046] Figure 8 X-ray diffraction pattern of platinum-iron-cobalt-nickel-zinc-tin intermetallic compound electrocatalyst prepared in Example 2.

[0047] Figure 9 Transmission electron microscope image of platinum-cobalt-nickel-copper-zinc-indium intermetallic compound electrocatalyst prepared in Example 3.

[0048] Figure 10 X-ray diffraction pattern of platinum-cobalt-nickel-copper-zinc-indium intermetallic compound electrocatalyst prepared in Example 3.

[0049] Figure 11Transmission electron microscope image of the platinum-manganese-iron-cobalt-nickel-copper-zinc-gallium-indium-tin intermetallic compound electrocatalyst prepared in Example 4.

[0050] Figure 12 X-ray diffraction pattern of the platinum-manganese-iron-cobalt-nickel-copper-zinc-gallium-indium-tin intermetallic compound electrocatalyst prepared in Example 4.

[0051] Figure 13 Transmission electron microscope image of the platinum-nickel-zinc-gallium-indium-tin intermetallic compound electrocatalyst prepared in Example 5.

[0052] Figure 14 X-ray diffraction pattern of the platinum-nickel-zinc-gallium-indium-tin intermetallic compound electrocatalyst prepared in Example 5. Detailed implementation manners

[0053] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the following further elaborates on the present invention in detail in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and should not be construed as limiting the present invention.

[0054] Example 1

[0055] (1) Dissolve 0.025 mmol of platinum acetylacetonate, 0.005 mmol of iron acetylacetonate, 0.005 mmol of cobalt acetylacetonate, 0.005 mmol of nickel acetylacetonate, 0.005 mmol of copper acetylacetonate, 0.005 mmol of tin dichloride and 0.075 mmol of molybdenum hexacarbonyl in 5 mL of oleylamine to form a homogeneous solution.

[0056] (2) Place the homogeneous solution formed in step (1) in an oil bath at 200 °C and react for 12 hours, then naturally cool to room temperature to obtain a black colloidal solution.

[0057] (3) Add 10 mL of ethanol to the black colloidal solution obtained in step (2), centrifuge at 8500 rpm / min for 5 minutes and wash with a cyclohexane / ethanol mixed solution with a volume ratio of 1 / 3 to obtain platinum-iron-cobalt-nickel-copper-tin alloy nanoparticles.

[0058] (4) Weigh 10 mg of Ketjen black and ultrasonically disperse it in 20 mL of ethanol to form a homogeneous dispersion. Drop the platinum-iron-cobalt-nickel-copper-tin alloy nanoparticles obtained in step (3) into the carbon dispersion, ultrasonicate for 2 hours and then centrifuge and separate, wash three times with ethanol, and after drying, carbon-supported platinum-iron-cobalt-nickel-copper-tin alloy nanoparticles can be obtained.

[0059] (5) Calcinate the carbon-supported platinum-iron-cobalt-nickel-copper-tin alloy nanoparticles obtained in step (4) in air at 230 °C for 2 hours.

[0060] (6) The product obtained in step (5) is placed in a tubular furnace with a 5% hydrogen-argon mixture and calcined at 500 °C for 6 hours to obtain a platinum-iron-cobalt-nickel-copper-tin high-entropy intermetallic compound electrocatalyst.

[0061] Figure 1 shows the morphological characteristics of the platinum-iron-cobalt-nickel-copper-tin alloy nanoparticles obtained in step (3), indicating that they have a monodispersed characteristic with a particle size of 4.2 ± 0.3 nm. Figure 2 shows the structural information of the platinum-iron-cobalt-nickel-copper-tin alloy nanoparticles, indicating that they are a face-centered cubic single-phase solid solution structure.

[0062] Figure 3 shows the morphological characteristics of the platinum-iron-cobalt-nickel-copper-tin high-entropy intermetallic compound electrocatalyst obtained in step (6), indicating that the nanoparticles are evenly dispersed on the carbon material, and the particle size of the dispersed nanoparticles is 4.5 ± 0.7 nm. Figure 4 shows the structural information of the platinum-iron-cobalt-nickel-copper-tin high-entropy intermetallic compound electrocatalyst, indicating that it has a crystal structure similar to that of the L10-phase intermetallic platinum-cobalt, confirming the formation of the high-entropy intermetallic compound.

[0063] Figure 5 shows the atomic-level structural characteristics of a single platinum-iron-cobalt-nickel-copper-tin high-entropy intermetallic compound nanoparticle. The brighter atoms in the figure are platinum atoms, and the darker atoms are iron, cobalt, nickel, copper, or tin atoms. The platinum atoms and the remaining atoms are regularly and orderly arranged, thus forming the L10-phase intermetallic structure of the platinum-iron-cobalt-nickel-copper-tin high-entropy intermetallic compound nanoparticle. Figure 6 shows the component distribution characteristics of a single platinum-iron-cobalt-nickel-copper-tin high-entropy intermetallic compound nanoparticle, indicating that platinum, iron, cobalt, nickel, copper, and tin elements are evenly distributed in the nanoparticle without phase separation.

[0064] Example 2

[0065] (1) 0.05 mmol of platinum acetylacetonate, 0.015 mmol of iron acetylacetonate, 0.015 mmol of cobalt acetylacetonate, 0.005 mmol of nickel acetylacetonate, 0.005 mmol of zinc acetylacetonate, 0.01 mmol of tin dichloride, and 0.15 mmol of molybdenum hexacarbonyl are dissolved in 10 mL of oleylamine to form a homogeneous solution.

[0066] (2) The homogeneous solution formed in step (1) is placed in an oil bath at 200 °C and reacted for 12 hours, and then naturally cooled to room temperature to obtain a black colloidal solution.

[0067] (3) Add 10 mL of ethanol to the black colloidal solution obtained in step (2), centrifuge at 8500 rpm for 5 minutes, and wash with a cyclohexane / ethanol mixture with a volume ratio of 1 / 3 to obtain platinum-iron-cobalt-nickel-zinc-tin alloy nanoparticles.

[0068] (4) Weigh 20 mg of Ketjen black and ultrasonically disperse it in 40 mL of ethanol to form a uniform dispersion. Drop the platinum-iron-cobalt-nickel-copper-tin alloy nanoparticles obtained in step (3) into the carbon dispersion, ultrasonically treat for 3 hours, then centrifuge and separate, wash three times with ethanol, and after drying, carbon-supported platinum-iron-cobalt-nickel-zinc-tin alloy nanoparticles can be obtained.

[0069] (5) Calcinate the carbon-supported platinum-iron-cobalt-nickel-zinc-tin alloy nanoparticles obtained in step (4) in air at 230 °C for 2 hours.

[0070] (6) Place the product obtained in step (5) in a tubular furnace with a 5% hydrogen-argon mixture and calcine at 600 °C for 6 hours to obtain a platinum-iron-cobalt-nickel-zinc-tin high-entropy intermetallic compound electrocatalyst.

[0071] Figure 7 (6) shows the morphological characteristics of the platinum-iron-cobalt-nickel-zinc-tin high-entropy intermetallic compound electrocatalyst obtained in step (6), indicating that the nanoparticles are uniformly dispersed on the carbon material, and the particle size of the dispersed nanoparticles is 5.0 ± 1.0 nm. Figure 8 (7) shows the structural information of the platinum-iron-cobalt-nickel-zinc-tin high-entropy intermetallic compound electrocatalyst, indicating that it has a crystal structure similar to that of the intermetallic platinum-cobalt of the L10 phase, confirming the formation of the high-entropy intermetallic compound.

[0072] Example 3

[0073] (1) Dissolve 0.04 mmol of platinum acetylacetonate, 0.008 mmol of cobalt acetylacetonate, 0.008 mmol of nickel acetylacetonate, 0.008 mmol of copper acetylacetonate, 0.008 mmol of zinc acetylacetonate, 0.008 mmol of indium triacetylacetonate, and 0.10 mmol of molybdenum hexacarbonyl in 8 mL of oleylamine to form a uniform solution.

[0074] (2) Place the uniform solution formed in step (1) in an oil bath at 200 °C and react for 10 hours, then naturally cool to room temperature to obtain a black colloidal solution.

[0075] (3) Add 10 mL of ethanol to the black colloidal solution obtained in step (2), centrifuge at 8500 rpm for 5 minutes, and wash with a cyclohexane / ethanol mixture with a volume ratio of 1 / 3 to obtain platinum-cobalt-nickel-copper-zinc-indium alloy nanoparticles.

[0076] (4) Weigh 15 mg of Ketjen black and ultrasonically disperse it in 30 mL of ethanol to form a uniform dispersion. Drop the platinum-cobalt-nickel-copper-zinc-indium alloy nanoparticles obtained in step (3) into the carbon dispersion, ultrasonicate for 2.5 hours, then centrifuge and separate. Wash three times with ethanol, and after drying, carbon-supported platinum-cobalt-nickel-copper-zinc-indium alloy nanoparticles can be obtained.

[0077] (5) Calcinate the carbon-supported platinum-cobalt-nickel-copper-zinc-indium alloy nanoparticles obtained in step (4) in air at 230 °C for 2 hours.

[0078] (6) Place the product obtained in step (5) in a tube furnace with a 5% hydrogen-argon mixed gas and calcine at 550 °C for 6 hours to obtain a platinum-cobalt-nickel-copper-zinc-indium high-entropy intermetallic compound electrocatalyst.

[0079] Figure 9 shows the morphological characteristics of the platinum-cobalt-nickel-copper-zinc-indium high-entropy intermetallic compound electrocatalyst obtained in step (6), indicating that the nanoparticles are uniformly dispersed on the carbon material, and the particle size of the dispersed nanoparticles is 4.5 ± 0.7 nm. Figure 10 shows the structural information of the platinum-cobalt-nickel-copper-zinc-indium high-entropy intermetallic compound electrocatalyst, indicating that it has a crystal structure similar to that of the L10-phase intermetallic platinum-cobalt, confirming the formation of the high-entropy intermetallic compound.

[0080] Example 4

[0081] (1) Dissolve 0.09 mmol of platinum acetylacetonate, 0.01 mmol of manganese acetylacetonate, 0.01 mmol of iron acetylacetonate, 0.01 mmol of cobalt acetylacetonate, 0.01 mmol of nickel acetylacetonate, 0.01 mmol of copper acetylacetonate, 0.01 mmol of zinc acetylacetonate, 0.01 mmol of gallium acetylacetonate, 0.01 mmol of indium acetylacetonate, 0.01 mmol of tin dichloride, and 0.18 mmol of molybdenum hexacarbonyl in 18 mL of oleylamine to form a uniform solution.

[0082] (2) Place the uniform solution formed in step (1) in an oil bath at 200 °C and react for 10 hours, then naturally cool to room temperature to obtain a black colloidal solution.

[0083] (3) Add 40 mL of ethanol to the black colloidal solution obtained in step (2), centrifuge at 9000 rpm / min for 5 minutes, and wash with a cyclohexane / ethanol mixed solution with a volume ratio of 1 / 3 to obtain platinum-manganese-iron-cobalt-nickel-copper-zinc-gallium-indium-tin alloy nanoparticles.

[0084] (4) Weigh 30 mg of Ketjen black and ultrasonically disperse it in 60 mL of ethanol to form a uniform dispersion. Drop the platinum-manganese-iron-cobalt-nickel-copper-zinc-gallium-indium-tin alloy nanoparticles obtained in step (3) into the carbon dispersion, ultrasonicate for 3 hours, then centrifuge and separate. Wash three times with ethanol, and after drying, carbon-supported platinum-manganese-iron-cobalt-nickel-copper-zinc-gallium-indium-tin alloy nanoparticles can be obtained.

[0085] (5) Place the carbon-supported platinum-manganese-iron-cobalt-nickel-copper-zinc-gallium-indium-tin alloy nanoparticles obtained in step (4) in air at 230 °C and calcine for 2 hours.

[0086] (6) Place the product obtained in step (5) in a tubular furnace with a 5% hydrogen-argon mixed gas and calcine at 500 °C for 6 hours, then a platinum-manganese-iron-cobalt-nickel-copper-zinc-gallium-indium-tin high-entropy intermetallic compound electrocatalyst can be obtained.

[0087] Figure 11 The morphological characteristics of the platinum-manganese-iron-cobalt-nickel-copper-zinc-gallium-indium-tin high-entropy intermetallic compound electrocatalyst obtained in step (6) are shown, indicating that the nanoparticles are evenly dispersed on the carbon material, and the particle size of the dispersed nanoparticles is 4.2 ± 0.3 nm. Figure 12 The structural information of the platinum-manganese-iron-cobalt-nickel-copper-zinc-gallium-indium-tin high-entropy intermetallic compound electrocatalyst is shown, indicating that it has a crystal structure similar to that of the L10-phase intermetallic platinum-cobalt, confirming the formation of the high-entropy intermetallic compound.

[0088] Example 5

[0089] (1) Dissolve 0.05 mmol of platinum acetylacetonate, 0.01 mmol of nickel acetylacetonate, 0.01 mmol of zinc acetylacetonate, 0.01 mmol of gallium triacetylacetonate, 0.01 mmol of indium triacetylacetonate, 0.01 mmol of tin dichloride, and 0.10 mmol of molybdenum hexacarbonyl in 10 mL of oleylamine to form a uniform solution.

[0090] (2) Place the uniform solution formed in step (1) in an oil bath at 200 °C and react for 12 hours, then naturally cool to room temperature to obtain a black colloidal solution.

[0091] (3) Add 40 mL of ethanol to the black colloidal solution obtained in step (2), centrifuge at 9000 rpm / min for 5 minutes, and wash with a cyclohexane / ethanol mixed solution with a volume ratio of 1 / 3, then platinum-nickel-zinc-gallium-indium-tin alloy nanoparticles can be obtained.

[0092] (4) Weigh 20 mg of Ketjen black and ultrasonically disperse it in 40 mL of ethanol to form a uniform dispersion. Drop the platinum-nickel-zinc-gallium-indium-tin alloy nanoparticles obtained in step (3) into the carbon dispersion, ultrasonicate for 3 hours, then centrifuge and separate. Wash three times with ethanol, and after drying, carbon-supported platinum-nickel-zinc-gallium-indium-tin alloy nanoparticles can be obtained.

[0093] (5) The carbon-supported platinum-nickel-zinc-gallium-indium-tin alloy nanoparticles obtained in step (4) are calcined in air at 230 °C for 2 hours.

[0094] (6) The product obtained in step (5) is placed in a tubular furnace with a 5% hydrogen-argon mixture and calcined at 400 °C for 6 hours to obtain the platinum-nickel-zinc-gallium-indium-tin high-entropy intermetallic compound electrocatalyst.

[0095] Figure 13 Shows the morphological characteristics of the platinum-nickel-zinc-gallium-indium-tin high-entropy intermetallic compound electrocatalyst obtained in step (6), indicating that the nanoparticles are evenly dispersed on the carbon material, and the particle size of the dispersed nanoparticles is 4.0 ± 0.4 nm. Figure 14 Shows the structural information of the platinum-nickel-zinc-gallium-indium-tin high-entropy intermetallic compound electrocatalyst, indicating that it has a crystal structure similar to that of the intermetallic platinum-nickel in the L10 phase, confirming the formation of the high-entropy intermetallic compound.

[0096] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and purposes of the present invention.

Claims

1. A multi-metal platinum-based alloy nanoparticle, having a disordered solid solution structure, contains at least five different metal elements including platinum. The other metal elements except platinum are selected from 1 to 6 of the six metal elements of manganese, iron, cobalt, nickel, copper, and zinc, and 1 to 3 of the three metal elements of gallium, indium, and tin.

2. The multi-metal platinum-based alloy nanoparticles according to claim 1, wherein In the multi-metal platinum-based alloy nanoparticle, the atomic percentage of platinum atoms is 40% to 60%, and the atomic percentage of 1 to 3 of the three metal elements of gallium, indium, and tin is 5% to 35%.

3. The preparation method of the multi-metal platinum-based alloy nanoparticle according to claim 1 or 2, comprising the following steps: 1) Dissolve at least five metal precursor salts and a carbonyl compound reducing agent in oleylamine to form a homogeneous solution. The at least five metal precursor salts contain at least five different metal elements, and the at least five different metal elements refer to platinum, 1 to 6 of the six metal elements of manganese, iron, cobalt, nickel, copper, and zinc, and 1 to 3 of the three metal elements of gallium, indium, and tin; 2) Place the homogeneous solution formed in step 1) in an oil bath for a reduction reaction, and then naturally cool to room temperature to obtain a black colloidal solution; 3) Add ethanol to the black colloidal solution obtained in step 2) to obtain a precipitate. After centrifugal separation and washing with a cyclohexane / ethanol mixture, the multi-metal platinum-based alloy nanoparticle can be obtained.

4. The preparation method according to claim 3, characterized in that, In step 1), the metal precursor salts are selected from platinum acetylacetonate, manganese acetylacetonate, iron acetylacetonate, cobalt acetylacetonate, nickel acetylacetonate, copper acetylacetonate, zinc acetylacetonate, gallium acetylacetonate, indium acetylacetonate, and tin dichloride.

5. The preparation method according to claim 4, characterized in that, In step 1), the carbonyl compound reducing agent is selected from chromium hexacarbonyl, molybdenum hexacarbonyl, tungsten hexacarbonyl; in step 2), the oil bath temperature is 180 to 220 °C, and the reduction reaction time is 6 to 15 hours.

6. A platinum-based high-entropy intermetallic compound electrocatalyst. The electrocatalyst is a high-entropy intermetallic compound nanoparticle supported on a carbon carrier. The high-entropy intermetallic compound nanoparticle contains at least five different metal elements including platinum. The other metal elements except platinum are selected from 1 to 6 of the six metal elements of manganese, iron, cobalt, nickel, copper, and zinc, and 1 to 3 of the three metal elements of gallium, indium, and tin; in the high-entropy intermetallic compound nanoparticle, platinum atoms and other metal atoms are arranged in an orderly and regular manner, and the phase structure is the L10 phase.

7. The platinum-based high-entropy intermetallic compound electrocatalyst according to claim 6, wherein The carbon carrier is Ketjen black or XC-72 conductive carbon carrier; the size of the high-entropy intermetallic compound nanoparticle is 3 to 5 nm; in the high-entropy intermetallic compound nanoparticle, the atomic percentage of platinum atoms is 40% to 60%, and the atomic percentage of 1 to 3 of the three metal elements of gallium, indium, and tin is 5% to 35%.

8. The preparation method of the platinum-based high-entropy intermetallic compound electrocatalyst according to claim 6 or 7, comprising the following steps: a) Ultrasonically disperse the carbon support in ethanol to form a uniform carbon dispersion. Disperse the polymetallic platinum-based alloy nanoparticles described in Claim 1 or 2 in cyclohexane and drop it into the carbon dispersion. After ultrasonic mixing, centrifuge and separate, wash with ethanol multiple times, and obtain carbon-supported polymetallic platinum-based alloy nanoparticles after drying; b) Calcinate the carbon-supported polymetallic platinum-based alloy nanoparticles in air to remove impurity molecules; c) Place the product obtained in step b) in a reducing atmosphere and calcine at 400 - 600 °C to obtain the platinum-based high-entropy intermetallic compound electrocatalyst.

9. The preparation method according to claim 8, characterized in that, In step b), the calcination temperature in air is 220 - 240 °C and the time is 2 - 4 hours.

10. The preparation method according to claim 8, wherein In step c), the reducing atmosphere is a 5% hydrogen-argon mixed gas and the calcination time is 4 - 8 hours.

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