ORR multi-metal-doped platinum-based catalyst of fuel cell as well as preparation and application of ORR multi-metal-doped platinum-based catalyst

Abstract

The invention provides an ORR multi-metal-doped platinum-based catalyst of a fuel cell as well as preparation and application of the ORR multi-metal-doped platinum-based catalyst. The platinum-based catalyst comprises a matrix layer and a surface layer, the matrix layer comprises a carbon carrier and a Pt-M alloy; the surface layer comprises a carbon carrier, a Pt-M alloy base material, a doping element W and a doping element Au, wherein the doping element W and the doping element Au are doped in the Pt-M alloy base material. In the surface layer of the platinum-based catalyst provided by the invention, a Pt-M alloy base material is doped with a doping element W and a doping element Au; the doped element W weakens the adsorption strength of the platinum-based catalyst to an ORR reaction intermediate, and the catalytic activity of the platinum-based catalyst is improved; the doping element Au weakens the dissolution of the Pt element and the transition metal element, and the stability of the platinum-based catalyst is improved; the stress stability of crystal lattices is improved through the synergistic effect of the doping element W and the doping element Au, and the stability of the platinum-based catalyst is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fuel cells, and relates to an ORR multi-metal doped platinum-based catalyst for fuel cells, in particular to an ORR multi-metal doped platinum-based catalyst for fuel cells and a preparation and application thereof. BACKGROUND

[0002] With the increasingly serious problems of fossil energy consumption and carbon emissions, developing clean new energy has become a top priority. As a kind of efficient and clean power generation technology, fuel cells are attracting much attention due to their emission of only water vapor, high energy conversion efficiency, quiet operation and mild conditions. The basic principle of fuel cells is the reverse reaction of water electrolysis, which converts chemical energy into electrical energy through the reaction of hydrogen and oxygen, and is not limited by the Carnot cycle, especially suitable for fuel cell vehicles and portable power sources. With the continuous maturity of technology and the expansion of application scale, hydrogen fuel cells are expected to play an important role in the energy system and promote the transformation of green and low-carbon energy.

[0003] Electrocatalytic oxidation reactions mainly include oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which are the electrochemical basis of fuel cells and play a crucial role in the new generation of clean energy technologies. Among them, the oxygen reduction reaction process at the cathode is complex and has slow kinetics, so developing cathode oxygen reduction (ORR) catalysts is crucial for fuel cells.

[0004] In the prior art, platinum-carbon catalysts are the most widely used, but platinum-carbon catalysts have limited catalytic performance and can only increase the platinum loading to improve the discharge power of the battery, and platinum is a noble metal, which has high production and use costs, seriously restricting the widespread application of hydrogen fuel cells. Current platinum-based alloy catalysts have been proven to have higher catalytic activity than platinum-carbon catalysts.

[0005] However, the platinum-based alloy catalysts in the prior art have too strong adsorption strength for oxygen reduction reaction intermediates, which limits the reaction kinetics and thus limits the catalytic performance; in addition, the platinum-based alloy catalysts are prone to Pt element and transition metal element dissolution during operation, which leads to catalyst activity decay; in addition, the crystal lattice of the platinum-based alloy catalyst is prone to structural relaxation or phase separation during long-term operation, and the stress stability of the crystal lattice is insufficient, resulting in insufficient stability of the catalyst.

[0006] CN111224118A discloses a multi-doped platinum-based catalyst and a preparation method and use thereof. The preparation method of the platinum-based catalyst combines ion adsorption and rapid reduction processes to efficiently and rapidly form a doped platinum-based nanocrystal on the surface of a carbon material, and the method has the advantages of simple operation, easy control and suitability for engineering mass production.

[0007] CN119864435A discloses a residual oil derived carbon supported Pt-Co-Au intermetallic compound and its preparation method and application. The document uses residual oil as a carbon source, and synthesizes nitrogen-doped petroleum vacuum residual oil porous carbon by a template method and nitrogen-doping modification. A highly dispersed intermetallic compound composite Pt-Co-Au / NPPC is prepared by an impregnation reduction method using the porous carbon material as a carrier. The total metal loading in the catalyst is 30wt%-50wt%, the Pt loading is 26wt%-41wt%, the Co loading is 3.8wt%-7wt%, and the Au loading is 0.2wt%-2wt%.

[0008] In summary, the existing ORR platinum-based catalysts in the prior art have certain defects, and there are problems of insufficient catalytic performance caused by too strong adsorption strength of the ORR intermediate, and insufficient stability caused by easy dissolution of Pt elements and transition metal elements, and structural relaxation or phase separation during operation. Therefore, it is crucial to develop and design a new type of ORR multi-metal doped platinum-based catalyst for fuel cells and its preparation and application. SUMMARY

[0009] In view of the deficiencies of the prior art, the purpose of the present application is to provide an ORR multi-metal doped platinum-based catalyst for fuel cells and its preparation and application. The platinum-based catalyst provided by the present application has the following characteristics: the surface layer of the platinum-based catalyst is doped with a doping element W and a doping element Au in the Pt-M alloy substrate; the doping element W reduces the adsorption strength of the platinum-based catalyst on the ORR intermediate, thereby improving the catalytic activity of the platinum-based catalyst; the doping element Au reduces the dissolution of Pt elements and transition metal elements, thereby improving the stability of the platinum-based catalyst; and the synergistic effect of the doping element W and the doping element Au improves the stress stability of the crystal lattice, thereby improving the stability of the platinum-based catalyst.

[0010] To achieve this purpose, the present application adopts the following technical solutions:

[0011] In a first aspect, the present application provides an ORR multi-metal doped platinum-based catalyst for fuel cells, which comprises a substrate layer and a surface layer.

[0012] The substrate layer comprises a carbon carrier and a Pt-M alloy.

[0013] The surface layer comprises a carbon carrier, a Pt-M alloy substrate, and a doping element W and a doping element Au doped in the Pt-M alloy substrate.

[0014] The Pt-M alloy substrate in the surface layer of the platinum-based catalyst is doped with the doping element W and the doping element Au; on one hand, the doping element W reduces the d-band center of the Pt-M alloy substrate in the surface layer, weakens the adsorption strength of the platinum-based catalyst on the ORR reaction intermediate (OH·), and improves the catalytic activity of the platinum-based catalyst; on the other hand, the doping element Au regulates the electronic structure of the Pt element and the transition metal element atoms in the Pt-M alloy substrate in the surface layer, weakens the dissolution of the Pt element and the transition metal element, and improves the stability of the platinum-based catalyst; on the other hand, the synergistic effect of the doping element W and the doping element Au regulates the atomic spacing of the Pt-M alloy substrate, improves the stress stability of the crystal lattice, and further improves the stability of the platinum-based catalyst.

[0015] Preferably, the M element in the Pt-M alloy in the substrate layer includes any one or a combination of at least two of Fe, Co or Ni, and typical but non-limiting combinations include a combination of Fe and Co, a combination of Co and Ni, a combination of Fe and Ni, or a combination of Fe, Co and Ni.

[0016] Preferably, the M element in the Pt-M alloy substrate includes any one or a combination of at least two of Fe, Co or Ni, and typical but non-limiting combinations include a combination of Fe and Co, a combination of Co and Ni, a combination of Fe and Ni, or a combination of Fe, Co and Ni.

[0017] Preferably, in the platinum-based catalyst, the mass fraction of the Pt element is 20wt% to 40wt%, for example, can be 20wt%, 22wt%, 24wt%, 26wt%, 28wt%, 30wt%, 32wt%, 34wt%, 36wt%, 38wt% or 40wt%, but is not limited to the listed values, and other values not listed in this range are also applicable.

[0018] Preferably, in the platinum-based catalyst, the mass fraction of the doping element W is 2wt% to 3wt%, and the mass fraction of the doping element Au is 0.2wt% to 1.2wt%.

[0019] In the present application, in the platinum-based catalyst, the mass fraction of the doping element W is 2wt% to 3wt%, for example, can be 2.0wt%, 2.1wt%, 2.2wt%, 2.3wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.7wt%, 2.8wt%, 2.9wt% or 3.0wt%, but is not limited to the listed values, and other values not listed in this range are also applicable.

[0020] In the present application, the mass fraction of the doping element Au in the platinum-based catalyst is 0.2wt% to 1.2wt%, for example, it can be 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 1wt% or 1.2wt%, but not limited to the listed values, and other values not listed in this range are also applicable.

[0021] In a second aspect, the present application provides a preparation method of the platinum-based catalyst of the first aspect, the preparation method comprising:

[0022] After mixing the carbon-supported Pt-M alloy, the W source and the Au source, heat treatment is performed in a reducing atmosphere to obtain the ORR multi-metal doped platinum-based catalyst.

[0023] Preferably, the method for preparing the carbon-supported Pt-M alloy comprises:

[0024] After mixing the Pt salt precursor, the M salt precursor, the reducing agent, the carbon carrier and the solvent, heating reduction is performed to obtain the carbon-supported Pt-M alloy.

[0025] Preferably, in the method for preparing the carbon-supported Pt-M alloy, the molar ratio of the Pt element in the Pt salt precursor to the M element in the M salt precursor is (1-3):1, for example, it can be 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1 or 3:1, but not limited to the listed values, and other values not listed in this range are also applicable.

[0026] Preferably, in the method for preparing the carbon-supported Pt-M alloy, the mass ratio of the Pt salt precursor to the reducing agent is 1:(0.25-15), for example, it can be 1:0.25, 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:12 or 1:15, but not limited to the listed values, and other values not listed in this range are also applicable.

[0027] Preferably, in the method for preparing the carbon-supported Pt-M alloy, the mass ratio of the Pt salt precursor to the solvent is 1:(10-200), for example, it can be 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, 1:120, 1:140, 1:160, 1:180 or 1:200, but not limited to the listed values, and other values not listed in this range are also applicable.

[0028] Preferably, the Pt salt precursor comprises any one of, or a combination of at least two of, platinum acetylacetonate, chloroplatinic acid, potassium chloroplatinate, platinum nitrate, typically but not limitedly, a combination of platinum acetylacetonate and chloroplatinic acid, a combination of potassium chloroplatinate and platinum nitrate, a combination of platinum acetylacetonate and potassium chloroplatinate, or a combination of chloroplatinic acid, potassium chloroplatinate and platinum nitrate.

[0029] Preferably, the M salt precursor comprises any one of, or a combination of at least two of, a Fe salt precursor, a Co salt precursor, or a Ni salt precursor, typically but not limitedly, a combination of a Fe salt precursor and a Co salt precursor, a combination of a Co salt precursor and a Ni salt precursor, a combination of a Fe salt precursor and a Ni salt precursor, or a combination of a Fe salt precursor, a Co salt precursor and a Ni salt precursor.

[0030] Preferably, the Fe salt precursor comprises any one of, or a combination of at least two of, iron acetylacetonate, iron nitrate, iron chloride or iron sulfate, typically but not limitedly, a combination of iron acetylacetonate and iron nitrate, a combination of iron nitrate and iron chloride, a combination of iron chloride and iron sulfate, a combination of iron nitrate and iron sulfate, or a combination of iron nitrate, iron chloride and iron sulfate.

[0031] Preferably, the Co salt precursor comprises any one of, or a combination of at least two of, cobalt acetylacetonate, cobalt nitrate, cobalt chloride or cobalt sulfate, typically but not limitedly, a combination of cobalt acetylacetonate and cobalt nitrate, a combination of cobalt nitrate and cobalt chloride, a combination of cobalt chloride and cobalt sulfate, a combination of cobalt nitrate and cobalt sulfate, or a combination of cobalt nitrate, cobalt chloride and cobalt sulfate.

[0032] Preferably, the Ni salt precursor comprises any one of, or a combination of at least two of, nickel acetylacetonate, nickel nitrate, nickel chloride or nickel sulfate, typically but not limitedly, a combination of nickel acetylacetonate and nickel nitrate, a combination of nickel nitrate and nickel chloride, a combination of nickel chloride and nickel sulfate, a combination of nickel nitrate and nickel sulfate, or a combination of nickel nitrate, nickel chloride and nickel sulfate.

[0033] Preferably, the reducing agent comprises any one of, or a combination of at least two of, ethylene glycol, sodium borohydride, ascorbic acid or sodium citrate, typically but not limitedly, a combination of ethylene glycol and sodium borohydride, a combination of ascorbic acid and sodium citrate, a combination of ethylene glycol and ascorbic acid, or a combination of ethylene glycol, ascorbic acid and sodium citrate.

[0034] Preferably, the carbon support comprises any one or a combination of at least two of XC-72, EC-300J or EC-600JD, typically but not limitedly, the combination includes XC-72 and EC-300J, EC-300J and EC-600JD, or XC-72, EC-300J and EC-600JD.

[0035] Preferably, the solvent comprises any one or a combination of at least two of oleylamine, ethylene glycol or N,N-dimethylformamide, typically but not limitedly, the combination includes oleylamine and ethylene glycol, ethylene glycol and N,N-dimethylformamide, oleylamine and N,N-dimethylformamide, or oleylamine, ethylene glycol and N,N-dimethylformamide.

[0036] Preferably, the temperature of the heating reduction is 50-300℃, and the time is 1-4h.

[0037] In the present application, the temperature of the heating reduction is 50-300℃, for example, it can be 50℃, 80℃, 100℃, 120℃, 150℃, 180℃, 200℃, 220℃, 250℃, 280℃ or 300℃, but not limited to the listed values, other values not listed in the range are also applicable.

[0038] In the present application, the time of the heating reduction is 1-4h, for example, it can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4h, but not limited to the listed values, other values not listed in the range are also applicable.

[0039] Preferably, when the reducing agent is ethylene glycol, the temperature of the heating reduction is 180-220℃, and the time is 1-4h.

[0040] In the present application, when the reducing agent is ethylene glycol, the temperature of the heating reduction is 180-220℃, for example, it can be 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃ or 220℃, but not limited to the listed values, other values not listed in the range are also applicable.

[0041] In the present application, when the reducing agent is ethylene glycol, the time of the heating reduction is 1-4h, for example, it can be 1h, 1.4h, 1.8h, 2h, 2.5h, 3h, 3.5h, 3.8h or 4h, but not limited to the listed values, other values not listed in the range are also applicable.

[0042] Preferably, when the reducing agent is sodium borohydride, the temperature of the heating reduction is 50-90℃, and the time is 1-2h.

[0043] In the present application, when the reducing agent is sodium borohydride, the temperature for heating reduction is 50-90℃, for example, it can be 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃ or 90℃, but not limited to the listed values, other values not listed in the range are also applicable.

[0044] In the present application, when the reducing agent is sodium borohydride, the time for heating reduction is 1-2h, for example, it can be 1h, 1.2h, 1.4h, 1.6h, 1.8h or 2h, but not limited to the listed values, other values not listed in the range are also applicable.

[0045] Preferably, when the reducing agent is ascorbic acid, the temperature for heating reduction is 140-220℃, and the time is 1-4h.

[0046] In the present application, when the reducing agent is ascorbic acid, the temperature for heating reduction is 140-220℃, for example, it can be 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃ or 220℃, but not limited to the listed values, other values not listed in the range are also applicable.

[0047] In the present application, when the reducing agent is ascorbic acid, the time for heating reduction is 1-4h, for example, it can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4h, but not limited to the listed values, other values not listed in the range are also applicable.

[0048] Preferably, when the reducing agent is sodium citrate, the temperature for heating reduction is 180-300℃, and the time is 1-4h.

[0049] In the present application, when the reducing agent is sodium citrate, the temperature for heating reduction is 180-300℃, for example, it can be 180℃, 200℃, 220℃, 240℃, 260℃, 280℃, 290℃ or 300℃, but not limited to the listed values, other values not listed in the range are also applicable.

[0050] In the present application, when the reducing agent is sodium citrate, the time for heating reduction is 1-4h, for example, it can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4h, but not limited to the listed values, other values not listed in the range are also applicable.

[0051] Preferably, the method for preparing the carbon-supported Pt-M alloy further comprises centrifugation, washing and drying successively after the heating reduction.

[0052] Preferably, the average particle size of the Pt-M alloy nanoparticles in the carbon-supported Pt-M alloy is 4-5 nm, for example, can be 4 nm, 4.1 nm, 4.2 nm, 4.3 nm, 4.4 nm, 4.5 nm, 4.6 nm, 4.7 nm, 4.8 nm, 4.9 nm or 5 nm, but not limited to the listed values, other values not listed in the range of values are also applicable.

[0053] Preferably, the W source includes any one or a combination of at least two of tungsten acetylacetonate, tungsten hexacarbonyl, ammonium metatungstate, sodium tungstate or tungsten trioxide, typical but non-limiting combinations include a combination of tungsten acetylacetonate and tungsten hexacarbonyl, a combination of tungsten hexacarbonyl and ammonium metatungstate, a combination of sodium tungstate and tungsten trioxide, a combination of ammonium metatungstate and tungsten trioxide, or a combination of tungsten hexacarbonyl, ammonium metatungstate and sodium tungstate.

[0054] Preferably, the Au source includes any one or a combination of at least two of chloroauric acid, gold acetate or gold nitrate, typical but non-limiting combinations include a combination of chloroauric acid and gold acetate, a combination of gold acetate and gold nitrate, a combination of chloroauric acid and gold nitrate, or a combination of chloroauric acid, gold acetate and gold nitrate.

[0055] Preferably, the reducing atmosphere is carried out in any one of a hydrogen-argon mixed atmosphere, a hydrogen-nitrogen mixed atmosphere, a hydrogen-helium mixed atmosphere.

[0056] Preferably, the volume ratio of hydrogen in the reducing atmosphere is 2-5%, for example, can be 2.0%, 2.2%, 2.4%, 2.6%, 2.8%, 3.0%, 3.2%, 3.4%, 3.6%, 3.8%, 4.0%, 4.2%, 4.4%, 4.6%, 4.8% or 5.0%, but not limited to the listed values, other values not listed in the range of values are also applicable.

[0057] Preferably, the temperature of the heat treatment is 250-350°C, and the time is 0.5-1.5 h.

[0058] In the present application, the temperature of the heat treatment is 250-350°C, for example, can be 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C or 350°C, but not limited to the listed values, other values not listed in the range of values are also applicable.

[0059] In the present application, the heat treatment time is 0.5h~1.5h, for example, it can be 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1.0h, 1.1h, 1.2h, 1.3h, 1.4h or 1.5h, but not limited to the listed values, other values not listed in the range are also applicable.

[0060] As a preferred technical solution of the preparation method of the present application, the preparation method comprises:

[0061] (1) After mixing the Pt salt precursor, the M salt precursor, the reducing agent, the carbon carrier and the solvent, heating reduction is performed to obtain a carbon-supported Pt-M alloy, wherein the average particle size of the Pt-M alloy in the carbon-supported Pt-M alloy is 4nm~5nm;

[0062] The molar ratio of Pt element in the Pt salt precursor to M element in the M salt precursor is (1~3):1; the mass ratio of the Pt salt precursor to the reducing agent is 1:(0.25~15); the mass ratio of the Pt salt precursor to the solvent is 1:(10~200);

[0063] The M salt precursor comprises any one or a combination of at least two of Fe salt precursor, Co salt precursor or Ni salt precursor;

[0064] The reducing agent comprises any one or a combination of at least two of ethylene glycol, sodium borohydride, ascorbic acid or sodium citrate;

[0065] The carbon carrier comprises any one or a combination of at least two of XC-72, EC-300J or EC-600JD;

[0066] The solvent comprises any one or a combination of at least two of oleylamine, ethylene glycol or N,N-dimethylformamide;

[0067] When the reducing agent is ethylene glycol, the heating reduction temperature is 180℃~220℃ and the time is 1h~4h; when the reducing agent is sodium borohydride, the heating reduction temperature is 50℃~90℃ and the time is 1h~2h; when the reducing agent is ascorbic acid, the heating reduction temperature is 140℃~220℃ and the time is 1h~4h; when the reducing agent is sodium citrate, the heating reduction temperature is 180℃~300℃ and the time is 1h~4h;

[0068] (2) After mixing the carbon-supported Pt-M alloy obtained in step (1), the W source and the Au source, heat treatment is performed at 250℃~350℃ for 0.5h~1.5h in any one of a hydrogen argon mixed atmosphere, a hydrogen nitrogen mixed atmosphere or a hydrogen helium mixed atmosphere with a hydrogen volume ratio of 2%~5% to obtain an ORR multi-metal doped platinum-based catalyst;

[0069] The W source includes any one of tungsten acetylacetonate, tungsten hexacarbonyl, ammonium metatungstate, sodium tungstate or tungsten trioxide or a combination of at least two thereof;

[0070] The Au source includes any one of chloroauric acid, gold acetate or gold nitrate or a combination of at least two thereof.

[0071] In a third aspect, the present application provides a fuel cell comprising the platinum-based catalyst according to the first aspect.

[0072] The numerical ranges recited herein are inclusive of the endpoints and also include any other ranges that can be stated or inferred from the stated ranges.

[0073] Compared with the prior art, the present application has the following beneficial effects:

[0074] In the surface layer of the platinum-based catalyst, the Pt-M alloy substrate is doped with the doping element W and the doping element Au; on the one hand, the doping element W reduces the d-band center of Pt in the Pt-M alloy substrate in the surface layer, weakens the adsorption strength of the platinum-based catalyst on the ORR reaction intermediate (OH·), and improves the catalytic activity of the platinum-based catalyst; on the other hand, the doping element Au regulates the electronic structure of the Pt element and the transition metal element atoms in the Pt-M alloy substrate in the surface layer, weakens the elution of the Pt element and the transition metal element, and improves the stability of the platinum-based catalyst; on the other hand, the synergistic effect of the doping element W and the doping element Au regulates the atomic spacing of the Pt-M alloy substrate, improves the stress stability of the crystal lattice, and further improves the stability of the platinum-based catalyst. BRIEF DESCRIPTION OF DRAWINGS

[0075] Figure 1 is a TEM image of the ORR multi-metal doped platinum-based catalyst of the fuel cell provided in Example 1 of the present application.

[0076] Figure 2 is an XRD image of the ORR multi-metal doped platinum-based catalyst of the fuel cell provided in Example 1 of the present application.

[0077] Figure 3 is the ORR forward scan polarization curve of the platinum-based catalyst provided in Example 1 of the present application in O2-saturated 0.1M HClO4 solution after initial and 30000-cycle accelerated decay tests.

[0078] Figure 4 is the cyclic voltammogram of the platinum-based catalyst provided in Example 1 of the present application after initial and 30000-cycle accelerated decay tests. DETAILED DESCRIPTION

[0079] The technical solutions of the present application will be further illustrated by the specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application, and should not be regarded as specific limitation to the present application.

[0080] The "range" disclosed in the present application can be defined in the form of lower limit and upper limit, a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of the specific range. The range defined in this way can be inclusive or exclusive of the end values, either end value can be independently included or excluded, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if the ranges of 60~120 and 80~110 are listed for a specific parameter, it is understood that the ranges of 60~110 and 80~120 are also anticipated. In addition, if the minimum range values of 1 and 2 are listed, and if the maximum range values of 3, 4 and 5 are also listed, the following ranges are all anticipated: 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5. In the present application, unless otherwise specified, the numerical range "a~b" represents a shorthand notation for any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between "0-5" have been listed herein, and "0~5" is only a shorthand notation for these numerical combinations. In addition, when it is stated that a parameter is an integer≥2, it is equivalent to listing the parameter as, for example, integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when it is stated that a parameter is an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9 and 10.

[0081] In the present application, "combination of at least two" means, unless otherwise specified, greater than or equal to 2 in number. For example, "any one or a combination of at least two" means one or greater than or equal to two. It can be understood that when referring to "combination of at least two", it means a combination of any suitable number of items, that is, a combination of "at least two" items in a way that is not conflicting and can implement the present application.

[0082] If not specifically stated, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0083] The term "embodiment" mentioned in the present application means that the specific features, structures or properties described in connection with the embodiment can be included in at least one embodiment or implementation of the present application. The appearance of this phrase at various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment that is not mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments.

[0084] Those skilled in the art can understand that in the method of each embodiment, the writing order of each step does not mean strict execution order, and the detailed execution order of each step should be determined by its function and possible inherent logic. If not specifically stated, all steps of the present application can be performed sequentially or randomly, and can be preferably performed sequentially. For example, the method comprises step (a) and step (b), which means that the method can comprise sequentially performed step (a) and step (b), or sequentially performed step (b) and step (a). For example, the method can also comprise step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0085] In the present application, the open technical features or technical solutions described by the words such as "include" do not exclude additional members other than the listed members, and can be regarded as providing both the closed features or technical solutions composed of the listed members and the open features or solutions including additional members in addition to the listed members. For example, A includes a1, a2 and a3, and unless otherwise specified, it can also include other members, or it can not include additional members, and it can be regarded as providing the technical features or technical solutions of "A is composed of a1, a2 and a3" or "A is selected from a1, a2 and a3", and also providing the technical features or technical solutions of "A not only includes a1, a2 and a3, but also includes other members".

[0086] In the present application, the terms "first", "second", "third", "fourth" and the like in "first aspect", "second aspect", "third aspect", "fourth aspect" and the like are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or quantity, nor can it be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth" and the like only serve the purpose of non-exhaustive enumeration description, and should be understood as not constituting a closed limitation on the quantity.

[0087] Embodiment 1

[0088] The embodiment provides an ORR multi-metal doped platinum-based catalyst of a fuel cell, the platinum-based catalyst comprising a substrate layer and a surface layer;

[0089] The substrate layer is composed of a carbon carrier (XC-72) and a Pt-Co alloy;

[0090] The surface layer is composed of a carbon carrier (XC-72) and a Pt-Co alloy substrate doped with a doping element W and a doping element Au;

[0091] Wherein, in percentage of the mass of the platinum-based catalyst, the mass fraction of the Pt element in the platinum-based catalyst is 30.2wt%, the mass fraction of the Co element is 7.5wt%, the mass fraction of the doping element W is 2.0wt%, the mass fraction of the doping element Au is 1.0wt%, and the balance is the carbon carrier (XC-72);

[0092] The preparation method of the platinum-based catalyst comprises:

[0093] (1) Pt salt precursor (platinum acetylacetone), Co salt precursor (cobalt acetylacetone) and reducing agent (ethylene glycol) are added into a solvent (oleylamine) containing a carbon carrier (XC-72), the molar ratio of the Pt element in the Pt salt precursor to the Co element in the Co salt precursor is controlled to be 1:1, the mass ratio of the Pt salt precursor to the reducing agent is 1:10, the mass ratio of the Pt salt precursor to the solvent is 1:120, and after being uniformly mixed, heating reduction is carried out at 210 DEG C for 2h to obtain a carbon-supported Pt-Co alloy, and in the carbon-supported Pt-Co alloy, the average particle size of the Pt-Co alloy is 4.3nm;

[0094] (2) the carbon-supported Pt-Co alloy obtained in step (1), W source (tungsten acetylacetone) and Au source (chloroauric acid) are mixed, and then heat treatment is carried out at 300 DEG C for 1h in a hydrogen argon mixed gas atmosphere with a hydrogen volume concentration of 5% to obtain the ORR multi-metal doped platinum-based catalyst;

[0095] The platinum-based catalyst in the embodiment is tested by using a transmission electron microscope, and the TEM diagram of the platinum-based catalyst is as shown in Figure 1 The platinum-based catalyst in the embodiment is tested by using an X-ray diffractometer, and the XRD diagram of the platinum-based catalyst is as shown in Figure 2 .

[0096] Embodiment 2

[0097] The embodiment provides an ORR multi-metal doped platinum-based catalyst of a fuel cell, the platinum-based catalyst comprising a substrate layer and a surface layer;

[0098] The substrate layer is composed of a carbon carrier (EC-300J) and a Pt-Ni alloy;

[0099] The surface layer is composed of a carbon carrier (EC-300J) and a Pt-Co alloy substrate doped with a doping element W and a doping element Au;

[0100] The mass fraction of the Pt element in the platinum-based catalyst is 30wt%, the mass fraction of the Ni element is 7.5wt%, the mass fraction of the doping element W is 2.2wt%, the mass fraction of the doping element Au is 0.8wt%, and the balance is the carbon carrier (EC-300J), all based on 100% by mass of the platinum-based catalyst;

[0101] The preparation method of the platinum-based catalyst comprises:

[0102] (1) adding a Pt salt precursor (chloroplatinic acid), a Ni salt precursor (nickel chloride), and a reducing agent (sodium citrate) into a solvent (ethylene glycol) containing a carbon carrier (EC-300J), controlling the molar ratio of the Pt element in the Pt salt precursor to the Ni element in the Ni salt precursor to be 1:1, the mass ratio of the Pt salt precursor to the reducing agent to be 1:6, and the mass ratio of the Pt salt precursor to the solvent to be 1:80, uniformly mixing, and then performing heating reduction at 180℃ for 2h to obtain a carbon-supported Pt-Ni alloy, wherein the average particle size of the Pt-Ni alloy in the carbon-supported Pt-Ni alloy is 4.9nm;

[0103] (2) mixing the carbon-supported Pt-Ni alloy obtained in step (1), a W source (tungsten acetylacetone), and an Au source (chloroauric acid), and then performing heat treatment at 280℃ for 1h in a hydrogen argon mixed gas atmosphere with a hydrogen volume concentration of 5% to obtain an ORR multi-metal doped platinum-based catalyst.

[0104] Example 3

[0105] The present embodiment provides an ORR multi-metal doped platinum-based catalyst for a fuel cell, which comprises a substrate layer and a surface layer.

[0106] The substrate layer is composed of a carbon carrier (EC-600JD) and a Pt-Co alloy;

[0107] The surface layer is composed of a carbon carrier (EC-600JD) and a Pt-Co alloy substrate doped with a doping element W and a doping element Au;

[0108] The mass fraction of the Pt element in the platinum-based catalyst is 30wt%, the mass fraction of the Co element is 7.5wt%, the mass fraction of the doping element W is 2.4wt%, the mass fraction of the doping element Au is 0.6wt%, and the balance is the carbon carrier (EC-600JD), all based on 100% by mass of the platinum-based catalyst;

[0109] The preparation method of the platinum-based catalyst comprises:

[0110] (1) Pt salt precursor (chloroplatinic acid), Co salt precursor (cobalt chloride) and reducing agent (ascorbic acid) are added to a solvent (ethylene glycol) containing carbon carrier (EC-600JD), and the molar ratio of Pt element in the Pt salt precursor to Co element in the Co salt precursor is controlled to be 3:1, the mass ratio of the Pt salt precursor to the reducing agent is 1:12, and the mass ratio of the Pt salt precursor to the solvent is 1:100, and after being uniformly mixed, heating reduction is carried out at 160℃ for 3h to obtain carbon-supported Pt-Co alloy, and in the carbon-supported Pt-Co alloy, the average particle size of the Pt-Co alloy is 4.0nm;

[0111] (2) The carbon-supported Pt-Co alloy obtained in step (1), W source (tungsten acetylacetonate) and Au source (chloroauric acid) are mixed, and then heat treatment is carried out at 280℃ for 1.5h in a hydrogen argon mixed gas atmosphere with a hydrogen volume concentration of 5% to obtain an ORR multi-metal doped platinum-based catalyst.

[0112] Example 4

[0113] The present embodiment provides an ORR multi-metal doped platinum-based catalyst for fuel cells, wherein the mass fraction of the doping element W in the platinum-based catalyst is 1.0wt%, and the average particle size of the Pt-Co alloy obtained in step (1) of the preparation method of the platinum-based catalyst is 4.2nm, except that the mass of the platinum-based catalyst is 100%, and the rest is the same as in Example 1.

[0114] Example 5

[0115] The present embodiment provides an ORR multi-metal doped platinum-based catalyst for fuel cells, wherein the mass fraction of the doping element W in the platinum-based catalyst is 4.0wt%, and the average particle size of the Pt-Co alloy obtained in step (1) of the preparation method of the platinum-based catalyst is 4.4nm, except that the mass of the platinum-based catalyst is 100%, and the rest is the same as in Example 1.

[0116] Example 6

[0117] The present embodiment provides an ORR multi-metal doped platinum-based catalyst for fuel cells, wherein the mass fraction of the doping element Au in the platinum-based catalyst is 0.1wt%, and the average particle size of the Pt-Co alloy obtained in step (1) of the preparation method of the platinum-based catalyst is 4.3nm, except that the mass of the platinum-based catalyst is 100%, and the rest is the same as in Example 1.

[0118] Example 7

[0119] The embodiment provides an ORR multi-metal doped platinum-based catalyst of a fuel cell, wherein, except that the mass fraction of a doped element Au in the platinum-based catalyst is 1.5 wt% and the average particle size of a Pt-Co alloy in a carbon-supported Pt-Co alloy obtained in step (1) of a preparation method of the platinum-based catalyst is 4.2 nm, the rest is the same as in embodiment 1.

[0120] Embodiment 8

[0121] The embodiment provides an ORR multi-metal doped platinum-based catalyst of a fuel cell, wherein, except that the average particle size of a Pt-Co alloy in a carbon-supported Pt-Co alloy obtained in step (1) of a preparation method of the platinum-based catalyst is 4.4 nm and the temperature of heat treatment in step (2) of the preparation method of the platinum-based catalyst is 200 DEG C, the rest is the same as in embodiment 1.

[0122] Embodiment 9

[0123] The embodiment provides an ORR multi-metal doped platinum-based catalyst of a fuel cell, wherein, except that the average particle size of a Pt-Co alloy in a carbon-supported Pt-Co alloy obtained in step (1) of a preparation method of the platinum-based catalyst is 4.3 nm and the temperature of heat treatment in step (2) of the preparation method of the platinum-based catalyst is 400 DEG C, the rest is the same as in embodiment 1.

[0124] Comparative example 1

[0125] The comparative example provides an ORR platinum-based catalyst of a fuel cell, wherein, except that a doped element W doped in the Pt-Co alloy substrate is omitted;

[0126] that is, a W source mixed in step (2) of a preparation method of the platinum-based catalyst is omitted, and the average particle size of a Pt-Co alloy in a carbon-supported Pt-Co alloy obtained in step (1) of the preparation method of the platinum-based catalyst is 4.4 nm, and the rest is the same as in embodiment 1.

[0127] Comparative example 2

[0128] The comparative example provides an ORR platinum-based catalyst of a fuel cell, wherein, except that a doped element Au doped in the Pt-Co alloy substrate is omitted;

[0129] that is, an Au source mixed in step (2) of a preparation method of the platinum-based catalyst is omitted, and the average particle size of a Pt-Co alloy in a carbon-supported Pt-Co alloy obtained in step (1) of the preparation method of the platinum-based catalyst is 4.3 nm, and the rest is the same as in embodiment 1.

[0130] Comparative example 3

[0131] The comparative example provides a platinum-based catalyst for ORR of a fuel cell, wherein the doping element W and the doping element Au doped in the Pt-Co alloy matrix substrate are omitted;

[0132] That is, step (2) of the preparation method of the platinum-based catalyst is omitted, and the average particle size of the Pt-Co alloy in the carbon-supported Pt-Co alloy obtained in step (1) of the preparation method of the platinum-based catalyst is 4.2 nm, and the rest is the same as in Example 1.

[0133] In step (1) of the preparation method of the platinum-based catalyst provided in the above examples and comparative examples, the average particle size of the Pt-M alloy nanoparticles in the carbon-supported Pt-M alloy obtained is counted, and the counting results are shown in Table 1; the mass fraction (content) of each element (Pt element, M element, W element and Au element) in the platinum-based catalyst is counted, and the counting results are shown in Table 1.

[0134] Table 1

[0135]

[0136] The platinum-based catalysts provided in all the above examples and comparative examples are subjected to performance testing, and the specific testing procedure is as follows: 3 mg of the platinum-based catalyst is dispersed in 780 μL of a mixture of isopropanol and 200 μL of deionized water, 20 μL of a 5% Nafion solution is added, and ultrasonic treatment is performed for 1 hour to obtain a test solution; part of the well-dispersed test solution is dropped and coated on a disc (0.2475 cm 2 ) electrode, and is sufficiently baked under a baking lamp to prepare an electrode head with a platinum catalyst loading of 40 μg · cm -2 , which is used for testing; the specific electrochemical characterization test is performed in a standard three-electrode system, the counter electrode is a carbon rod, and the reference electrode is a saturated calomel electrode; the test is performed at room temperature, the ORR polarization curve is measured in an O2-saturated 0.1 M HCIO4 electrolyte, and the background CV curve is measured in an N2-saturated 0.1 M HCIO4 electrolyte; the specific scanning potential is 0.1-1.1 V RHE , and the scanning rate is 10 mV · s -1 , the initial mass specific activity is tested, and the mass specific activity after 30000 cycles of decay test is tested, so as to calculate the initial mass specific activity decay rate after 30000 cycles of accelerated decay, which is shown in Table 2; wherein the ORR forward scan polarization curve of the platinum-based catalyst provided in Example 1 in the O2-saturated 0.1 M HCIO4 solution before and after 30000 cycles of accelerated decay test is shown in Figure 3As shown, the cyclic voltammograms of the platinum-based catalyst provided by Example 1 before and after 30000 cycles of accelerated degradation test are as follows Figure 4 As shown.

[0137] Table 2

[0138]

[0139] From Tables 1-2, it can be seen that:

[0140] (1) The ORR multi-metal doped platinum-based catalyst of the fuel cell provided in Examples 1-3 has high catalytic activity and excellent stability;

[0141] (2) As can be seen from the comparison between Example 1 and Examples 4 and 5, in the present application, the mass fraction of the doping element W in the platinum-based catalyst will affect the performance of the platinum-based catalyst, taking the mass of the platinum-based catalyst as 100%; when the mass fraction of the doping element W is 2wt%-3wt%, the platinum-based catalyst has better performance, because when the content of the doping element W is low, it cannot effectively regulate the electronic structure of Pt, the d-band center is still high, and the activity is not obviously improved, while when the content is high, thick layer WO x will be formed, which will cover the active sites on the surface of Pt, resulting in the inability of O2 and electrolyte to contact Pt, and the decrease of the activity of the catalyst;

[0142] (3) As can be seen from the comparison between Example 1 and Examples 6 and 7, in the present application, the mass fraction of the doping element Au in the platinum-based catalyst will affect the performance of the platinum-based catalyst, taking the mass of the platinum-based catalyst as 100%; when the mass fraction of the doping element Au is 0.2wt%-0.8wt%, the platinum-based catalyst has better stability, because when the content of the doping element Au is low, Au cannot significantly regulate the d-band center of Pt, it is difficult to weaken the strong adsorption of Pt and intermediate products, and it is difficult to inhibit the dissolution and loss of Pt, on the contrary, since Au has no ORR activity, too high content will occupy the active sites on the surface of Pt alloy, reducing the activity of the catalyst, and further increasing the cost of the catalyst;

[0143] (4) As can be seen from the comparison between Example 1 and Examples 8 and 9, in the preparation method of the platinum-based catalyst of the present application, the temperature of the heat treatment in step (2) will affect the performance of the platinum-based catalyst; when the temperature of the heat treatment is 250°C-350°C, the platinum-based catalyst has better performance, because when the temperature of the heat treatment is too low, the doping efficiency of the metal elements is low; while when the temperature of the heat treatment is too high, the doped metal particles are easy to agglomerate, reducing the performance of the catalyst, and at the same time, the particles will be doped into the phase, reducing the performance of the catalyst;

[0144] (5) Through comparison of the embodiment 1 and the comparative examples 1-3, it can be known that in the surface layer of the platinum-based catalyst, the Pt-M alloy substrate is doped with the doping element W and the doping element Au; on the one hand, the doping element W reduces the d-band center of Pt in the surface layer of the Pt-M alloy substrate, weakens the adsorption strength of the platinum-based catalyst on the ORR reaction intermediate (OH·), and improves the catalytic activity of the platinum-based catalyst; on the other hand, the doping element Au regulates the electronic structure of the Pt element and the transition metal element atoms in the surface layer of the Pt-M alloy substrate, weakens the dissolution of the Pt element and the transition metal element, and improves the stability of the platinum-based catalyst; on the other hand, the synergistic effect of the doping element W and the doping element Au regulates the atomic spacing of the Pt-M alloy substrate, improves the stress stability of the crystal lattice, and further improves the stability of the platinum-based catalyst.

[0145] The applicant declares that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and it should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought out by those skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. An ORR multi-metal doped platinum-based catalyst for a fuel cell, characterized in that, The platinum-based catalyst comprises a substrate layer and a surface layer; The substrate layer comprises a carbon carrier and a Pt-M alloy; The surface layer comprises a carbon carrier, a Pt-M alloy substrate, and a doping element W and a doping element Au doped in the Pt-M alloy substrate.

2. The platinum-based catalyst of claim 1, wherein, In the substrate layer, the M element in the Pt-M alloy comprises any one or a combination of at least two of Fe, Co, or Ni; Preferably, the M element in the Pt-M alloy substrate comprises any one or a combination of at least two of Fe, Co, or Ni; Preferably, in the platinum-based catalyst, the mass fraction of Pt element is 20wt%-40wt% based on 100% of the mass of the platinum-based catalyst; Preferably, in the platinum-based catalyst, the mass fraction of the doping element W is 2wt%-3wt%, and the mass fraction of the doping element Au is 0.2wt%-1.2wt% based on 100% of the mass of the platinum-based catalyst.

3. A process for the preparation of a platinum-based catalyst as claimed in claim 1 or 2, characterized in that, The preparation method comprises: After mixing the carbon-supported Pt-M alloy, the W source, and the Au source, heat treatment is performed in a reducing atmosphere to obtain an ORR multi-metal doped platinum-based catalyst.

4. The production method according to claim 3, characterized by, The method for preparing the carbon-supported Pt-M alloy comprises: After mixing a Pt salt precursor, an M salt precursor, a reducing agent, a carbon carrier, and a solvent, heating reduction is performed to obtain a carbon-supported Pt-M alloy; Preferably, in the method for preparing the carbon-supported Pt-M alloy, the molar ratio of Pt element in the Pt salt precursor to M element in the M salt precursor is (1-3):1; Preferably, in the method for preparing the carbon-supported Pt-M alloy, the mass ratio of the Pt salt precursor to the reducing agent is 1:(0.25-15); Preferably, in the method for preparing the carbon-supported Pt-M alloy, the mass ratio of the Pt salt precursor to the solvent is 1:(10-200); Preferably, the M salt precursor comprises any one or a combination of at least two of an Fe salt precursor, a Co salt precursor, or a Ni salt precursor; Preferably, the reducing agent comprises any one or a combination of at least two of ethylene glycol, sodium borohydride, ascorbic acid, or sodium citrate; Preferably, the carbon carrier comprises any one or a combination of at least two of XC-72, EC-300J, or EC-600JD; Preferably, the solvent comprises any one or a combination of at least two of oleylamine, ethylene glycol, or N,N-dimethylformamide; Preferably, the heating reduction is performed at a temperature of 50°C-300°C for 1h-4h; Preferably, in the carbon-supported Pt-M alloy, the average particle size of the Pt-M alloy nanoparticles is 4nm-5nm.

5. The preparation method according to claim 3, characterized in that, The W source comprises any one or a combination of at least two of tungsten acetylacetonate, tungsten hexacarbonyl, ammonium metatungstate, sodium tungstate, or tungsten trioxide.

6. The preparation method according to claim 3, characterized in that, The Au source comprises any one or a combination of at least two of chloroauric acid, gold acetate, or gold nitrate.

7. The preparation method according to claim 3, characterized in that, The reducing atmosphere comprises any one of a hydrogen-argon mixed atmosphere, a hydrogen-nitrogen mixed atmosphere, or a hydrogen-helium mixed atmosphere; Preferably, the volume fraction of hydrogen in the reducing atmosphere is 2%-5%.

8. The preparation method according to claim 3, characterized in that, The temperature of the heat treatment is 250-350 DEG C, and the time is 0.5-1.5 h.

9. The production method according to claim 3, wherein The preparation method comprises: (1) mixing a Pt salt precursor, an M salt precursor, a reducing agent, a carbon carrier and a solvent, and then performing heat reduction to obtain a carbon-supported Pt-M alloy, wherein the average particle size of the Pt-M alloy in the carbon-supported Pt-M alloy is 4-5 nm; The molar ratio of Pt in the Pt salt precursor to M in the M salt precursor is (1-3):1; the mass ratio of the Pt salt precursor to the reducing agent is 1:(0.25-15); and the mass ratio of the Pt salt precursor to the solvent is 1:(10-200); The M salt precursor comprises any one or a combination of at least two of an Fe salt precursor, a Co salt precursor or a Ni salt precursor; The reducing agent comprises any one or a combination of at least two of ethylene glycol, sodium borohydride, ascorbic acid or sodium citrate; The carbon carrier comprises any one or a combination of at least two of XC-72, EC-300J or EC-600JD; The solvent comprises any one or a combination of at least two of oleylamine, ethylene glycol or N,N-dimethylformamide; When the reducing agent is ethylene glycol, the temperature of the heat reduction is 180-220 DEG C, and the time is 1-4 h; when the reducing agent is sodium borohydride, the temperature of the heat reduction is 50-90 DEG C, and the time is 1-2 h; when the reducing agent is ascorbic acid, the temperature of the heat reduction is 140-220 DEG C, and the time is 1-4 h; and when the reducing agent is sodium citrate, the temperature of the heat reduction is 180-300 DEG C, and the time is 1-4 h; (2) mixing the carbon-supported Pt-M alloy obtained in step (1), a W source and an Au source, and then performing heat treatment at 250-350 DEG C for 0.5-1.5 h in a hydrogen-argon mixed gas atmosphere, a hydrogen-nitrogen mixed gas atmosphere or a hydrogen-helium mixed gas atmosphere, wherein the volume ratio of hydrogen is 2-5%, to obtain an ORR multi-metal doped platinum-based catalyst; The W source comprises any one or a combination of at least two of tungsten acetylacetonate, tungsten hexacarbonyl, ammonium metatungstate, sodium tungstate or tungsten trioxide; The Au source comprises any one or a combination of at least two of chloroauric acid, gold acetate or gold nitrate.

10. A fuel cell characterized by comprising: The fuel cell comprises the platinum-based catalyst according to claim 1 or 2.

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