Preparation method of molybdenum-doped platinum-cobalt-manganese alloy catalyst

Abstract

The invention discloses a molybdenum-doped platinum-cobalt-manganese alloy catalyst and a preparation method thereof.The method comprises the steps that a carbon carrier and an ammonium molybdate solution react and then are subjected to heat treatment to prepare a composite carrier, then cobalt-manganese salt and platinum salt are loaded in sequence, and the catalyst is obtained through step-by-step heat treatment and acid treatment; the obtained catalyst has the structural characteristic that the molybdenum-doped platinum-cobalt-manganese alloy nanoparticles are uniformly distributed on the molybdenum oxide modified nitrogen-doped carbon carrier. By optimizing the molybdenum doping amount, the alloy composition and the heat treatment process, the oxygen reduction activity and stability of the catalyst are remarkably improved, and the catalyst is suitable for the field of fuel cell cathode catalysis.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fuel cells, and relates to a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst. BACKGROUND

[0002] Reducing the platinum load in the catalytic layer is a necessary step in the commercialization process of proton exchange membrane fuel cells. Studies have shown that if a platinum-carbon catalyst is used, as the platinum load decreases, the active area of the catalyst layer will decrease significantly, and the mass transfer resistance of the membrane electrode in the high current density region will increase significantly, thereby seriously affecting the power density and service life of the fuel cell. Therefore, developing high-activity and high-durability alloy catalysts has become a key technology route for developing low-platinum-load fuel cells.

[0003] Currently, commercialized alloy catalysts are mainly platinum-cobalt binary catalysts. In the high potential cycle and high acidity environment of fuel cell working conditions, the dissolution of metal cobalt in the alloy catalytic layer will inevitably occur, which will significantly accelerate the decay of the membrane electrode.

[0004] CN114284516A discloses a low-Pt-load catalyst, a preparation method and applications thereof, and the method comprises the following steps: loading PtCeO2 on a non-noble metal catalyst to obtain PtCeO2@M-N-C, wherein M is a non-noble metal, C is a carbon element, and N is a nitrogen element; the catalyst carrier and the metal interface do not form a chemical bond, and the alloy components are unevenly distributed, which leads to easy dissolution in an acidic environment.

[0005] CN111668499A discloses a preparation method of a polyaniline-derived nitrogen-doped carbon-loaded multi-element alloy catalyst, comprising the following steps: (1) selecting a carbon cloth, and performing electrochemical polymerization in an electrolyte solution containing aniline to generate a polyaniline film adhering to the surface of the carbon cloth; (2) immersing the carbon cloth in a solution containing two or more metal salts, and taking out after standing; (3) placing the carbon cloth in a heating device, and performing high-temperature annealing treatment in a nitrogen protective atmosphere, and obtaining the polyaniline-derived nitrogen-doped carbon-loaded multi-element alloy catalyst after cooling; the catalyst carrier surface lacks transition metal oxide promoter sites, the mass transfer speed is low, and the nitrogen content is not high after high-temperature treatment, and the conductivity is deteriorated.

[0006] CN114388821A discloses a cobalt / molybdenum carbide composite material for electrolytic water hydrogen production and a preparation method thereof, comprising: mixing ammonium tetramolybdate, cobalt acetate tetrahydrate and melamine, and then directly carbonizing; the cobalt / molybdenum carbide composite material shows that the MoC particles are wrapped by a carbon layer under TEM, which hinders the electron transfer between the platinum alloy and the MoC, and the catalyst surface has many corrosion defects during dealloying treatment, and the stability is poor.

[0007] Therefore, based on reducing the dissolution speed of transition metals such as cobalt in the catalyst, improving the high activity and high durability of the catalyst, the patent proposes a preparation method of a molybdenum-doped platinum-cobalt-manganese ternary alloy catalyst, mainly through a unique preparation method, molybdenum elements are doped into the crystal structure of the alloy catalyst and the corresponding carbon carrier, so as to obtain a composite nano structure which can improve the stability of platinum atoms and alleviate the dissolution of transition metals, so as to realize the development of high-activity, high-durability alloy catalyst. SUMMARY

[0008] The purpose of the present application is to provide a molybdenum-doped platinum-cobalt-manganese alloy catalyst and a preparation method thereof, which has the characteristics of high activity, high stability and low platinum loading, and by constructing MoO z The synergistic structure of the nanometer island modified nitrogen-doped carbon composite carrier and the ordered PtCoMn alloy core, combined with the step-by-step heat treatment and controllable dealloying process, obtains a high-activity, high-durability catalyst.

[0009] The purpose of the present application can be realized by the following technical solutions: In a first aspect, the present application provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, which comprises the following steps: S1. The carbon carrier is adsorbed into an ammonium molybdate solution, filtered and dried, and then heat treated in an inert gas to obtain a composite carrier MoO z / C x N y , and after dispersion, a dispersion liquid A is obtained; S2. The composite carrier MoO z / C x N y After dispersion, a cobalt salt and a manganese salt solution are added to form a slurry, which is treated at 60 DEG C for 6-12h, and then heat treated at 600-900 DEG C in an inert gas to obtain a composite material B; S3. The composite material B is made into an ethylene glycol dispersion liquid, a chloroplatinic acid solution is added, and heating is carried out at 135 DEG C for 6-10h to obtain a composite material C; S4. The composite material C is treated at 750-800 DEG C in a hydrogen-argon mixed gas for 1-2h, and then treated at 900-1100 DEG C in an inert gas for 0.5-1.5h to obtain a composite material D; S5. The composite material D is dealloyed in 1-2M sulfuric acid at 80 DEG C for 48h to obtain the molybdenum-doped platinum-cobalt-manganese alloy catalyst.

[0010] The preparation method of the molybdenum-doped platinum-cobalt-manganese alloy catalyst provided by the present application realizes the in-situ oxidation-reduction reaction of molybdenum in an inert atmosphere at 700-950 DEG C through the adsorption-pyrolysis process of ammonium molybdate on the carbon carrier, forms MoO zNanometer islands, wherein 0 < z < 2, are chemically bonded to the nitrogen-doped carbon substrate through Mo-O-C bonds, wherein the introduction of nitrogen atoms can adjust the carbon electron cloud density, and the precise control of the Mo:C mass ratio of 1-30:70-100 can ensure sufficient metal anchoring sites and avoid the decrease of the carrier conductivity; this design inhibits the migration and aggregation of platinum alloy particles through strong metal-support interaction (SMSI).

[0011] The application provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, which induces alloy ordering through step-by-step heat treatment, removes oxygen impurities in the metal precursor through H2 reduction in a hydrogen-argon mixed gas stage, and promotes the initial mixing of Pt, Co and Mn atoms; during subsequent inert gas high-temperature treatment, MoO z Oxygen vacancies of MoO drive the ordered filling of Co / Mn to the Pt lattice as an atomic diffusion channel, forming a superlattice structure; during this process, Mo doping can also reduce the alloy formation energy and improve the atomic order, thereby significantly improving the intrinsic activity.

[0012] The application provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, which uses 1-2M sulfuric acid to preferentially dissolve Co / Mn atoms on the surface of the alloy, while Mo is retained due to the formation of a stable Mo-O coordination structure, which is a synergistic effect of raw material selection and preparation process.

[0013] Preferably, the mass ratio of Mo:N:C in the composite carrier obtained in step S1 is (1-30):(0.5-5):(65-98.5).

[0014] Preferably, the carbon carrier in step S1 is selected from at least one of carbon black, activated carbon, carbon fiber, multi-walled carbon nanotube, graphene and conductive graphite, and the particle size D 50 is 10nm-20μm.

[0015] The application provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, which uses a combination of carbon black, carbon nanotubes and other multi-dimensional carbon materials with D 50 The combination of carbon black, carbon nanotubes and other multi-dimensional carbon materials with D

[0016] Preferably, the molar ratio of cobalt salt to manganese salt Co:Mn in step S2 is (1-3):1, and the cobalt salt and manganese salt are acetate salts.

[0017] Preferably, the total time of the two heat treatments in step S4 is 1.5-3.5h.

[0018] Preferably, the mass ratio of alloy components to composite carrier in the final molybdenum-doped platinum-cobalt-manganese alloy catalyst is (20-60):(40-80).

[0019] Preferably, the atomic ratio of Mo:Pt:Co:Mn in the final molybdenum-doped platinum-cobalt-manganese alloy catalyst is (0.01-5):100:(0.01-35):(0.01-35).

[0020] The preparation method of the molybdenum-doped platinum-cobalt-manganese alloy catalyst provided by the present application controls the interface of the alloy and the carrier, and the mass ratio of the alloy components to the carrier is preferably (20-60):(40-80), which is based on the principle of interface energy balance: when the proportion of the alloy is > 60%, the surface anchoring sites of the carrier are overloaded, resulting in particle coarsening; and when the proportion of the alloy is < 20%, the active site density is insufficient; in the atomic ratio of Mo:Pt:Co:Mn, which is preferably (0.01-5):100:(0.01-35):(0.01-35), the trace doping of Mo can pin the grain boundary and inhibit the phase separation of the alloy at high temperature.

[0021] Preferably, the atomic ratio of Mo:Pt:Co:Mn is (1.5-4.5):100:(15-30):(8-15).

[0022] Preferably, the composite carrier MoO z / C x N y The atomic ratio of Mo to O is 100:(1-200).

[0023] In a second aspect, the present application also provides a molybdenum-doped platinum-cobalt-manganese alloy catalyst prepared by the above method, and the structure general formula is Mo-doped PtCoMn / MoO z @C x N y , wherein the platinum-based alloy nanoparticles are 2-10 nm in size, are uniformly loaded on the MoO z modified nitrogen-doped carbon carrier.

[0024] The present application has the following beneficial effects: (1) The preparation method of the molybdenum-doped platinum-cobalt-manganese alloy catalyst provided by the present application constructs a MoO z @C x Nᵧcarrier by in-situ pyrolysis of ammonium molybdate, the MoO z nanometer island structure anchors the platinum alloy particles, and the nitrogen-doped carbon improves the electrical conductivity; (2) The preparation method of the molybdenum-doped platinum-cobalt-manganese alloy catalyst provided by the present application adopts step-by-step heat treatment of hydrogen-argon mixed gas and inert gas to promote the formation of ordered structure of PtCoMn ternary alloy; (3) The molybdenum-doped platinum cobalt manganese alloy catalyst provided by the application is prepared by selectively dissolving non-noble metals (Co / Mn) with 1-2M sulfuric acid, forming a platinum-rich shell layer and retaining a Mo-doped core, and accelerating the mass transfer process of the oxygen reduction reaction. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to facilitate the understanding of those skilled in the art, the application will be further described below with reference to the accompanying drawings.

[0026] Figure 1 FIG. 1 is a structural schematic diagram of the alloy catalyst prepared in Example 1 of the application, wherein 1-Mo-doped PtCoMn, 2-MoO z , 3-C x N y carrier.

[0027] Figure 2 FIG. 2 is an element distribution schematic diagram in the alloy particles prepared in Example 1 of the application. DETAILED DESCRIPTION

[0028] In order to further illustrate the technical means and effects adopted by the application to achieve the predetermined application purposes, the specific embodiments, structures, features and effects according to the application are described in detail as follows.

[0029] In one specific embodiment, the application provides a preparation method of a molybdenum-doped platinum cobalt manganese alloy catalyst, which comprises the following steps: adding at least one carbon carrier (particle size D50 is 10nm-20μm) selected from carbon black, activated carbon, carbon fiber, multi-walled carbon nanotube, graphene or conductive graphite into a 0.5-1M ammonium molybdate solution for adsorption, filtering and drying, and then heat treating at 700-950℃ in an inert gas for 1-3h to obtain a composite carrier MoO z / C x N y(Mo:N:C mass ratio (1-30):(0.5-5):(65-98.5), Mo and O atom ratio 100:(1-200)), after dispersion, dispersion liquid A is obtained; the cobalt acetate and manganese acetate solution (Co:Mn molar ratio (1-3):1) is added into the dispersion liquid A to form a slurry, which is treated at 60℃ for 6-12h, and then heat treated at 600-900℃ for 2-4h in inert gas to obtain composite material B; the composite material B is made into ethylene glycol dispersion liquid, and the chloroplatinic acid solution is added, which is heated at 135℃ for 6-10h to obtain composite material C; the composite material C is treated at 750-800℃ for 1-2h in 5-10% hydrogen and argon mixed gas, and then treated at 900-1100℃ for 0.5-1.5h in inert gas to obtain composite material D; the composite material D is treated at 80℃ for 24-72h in 1-2M sulfuric acid to obtain a molybdenum-doped platinum-cobalt-manganese alloy catalyst (alloy component and composite carrier mass ratio (20-60):(40-80), Mo:Pt:Co:Mn atom ratio (0.01-5):100:(0.01-35):(0.01-35)), wherein the platinum-based alloy nanoparticle size is 2-10nm, which is uniformly loaded on the MoO z modified nitrogen-doped carbon carrier.

[0030] Example 1 The present embodiment provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, which comprises the following steps: S1, 10g of carbon black is added into 1M ammonium molybdate solution for adsorption, and after filtration and drying, it is heat treated at 900℃ for 1h in nitrogen to obtain composite carrier MoO z / CxNy (Mo:N:C=15%:1%:84%); S2, after dispersion of 10g of the composite carrier, the cobalt acetate and manganese acetate solution with Co:Mn=3:1 is added, which is treated at 60℃ for 12h and heat treated at 800℃ for 2h in argon; S3, the product is made into ethylene glycol dispersion liquid, and the chloroplatinic acid is added, which is heated at 135℃ for 6h; S4, it is treated at 800℃ for 1.5h in 5%H2 / Ar, and then treated at 1100℃ for 1.5h in nitrogen; S5, it is treated at 80℃ for 48h in 1M sulfuric acid to obtain the catalyst (Mo:Pt:Co:Mn=2:100:25:8, alloy / carrier=55:45).

[0031] The structural schematic diagram of the catalyst obtained in Example 1 is shown in Figure 1 , the alloy nanoparticle of Mo-doped PtCoMn is uniformly loaded on the MoO z modified nitrogen-doped carbon carrier, and the element distribution schematic diagram of the alloy particle of the catalyst in Example 1 is shown in Figure 2As shown, an ordered structure of PtCoMn ternary alloy is formed, which includes a platinum-rich shell layer and retains the Mo doping effect.

[0032] Example 2 The embodiment provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, and comprises the following steps: S1, 10g carbon black is added into a 0.5M ammonium molybdate solution, and heat treatment is performed at 800 DEG C for 1h under nitrogen, to obtain a carrier (Mo:N:C=10%:1%:89%); S2, a Co:Mn=2:1 acetate solution is added, and heat treatment is performed at 600 DEG C for 2h under argon; S3, heating at 135 DEG C for 10h; S4, 5%H2 / Ar treatment at 750 DEG C for 1h, and nitrogen treatment at 1000 DEG C for 1h; S5, 2M sulfuric acid dealloying treatment for 48h, to obtain a catalyst (Mo:Pt:Co:Mn=1.5:100:30:15, alloy / carrier=55:45).

[0033] Example 3 The embodiment provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, and comprises the following steps: S1, 5g carbon nanotubes+5g carbon black are added into a 0.5M ammonium molybdate solution, and heat treatment is performed at 700 DEG C for 1h under nitrogen, to obtain a carrier (Mo:N:C=8%:1%:91%); S2, a Co:Mn=1:1 acetate solution is added, and heat treatment is performed at 700 DEG C for 3h under argon; S3, heating at 135 DEG C for 10h; S4, 5%H2 / Ar treatment at 800 DEG C for 2h, and nitrogen treatment at 900 DEG C for 0.5h; S5, 2M sulfuric acid dealloying treatment for 48h, to obtain a catalyst (Mo:Pt:Co:Mn=4.5:100:15:15, alloy / carrier=50:50).

[0034] Example 4 The embodiment provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, and the difference from the embodiment 1 is that Mo:N:C=1%:0.5%:98.5% in S1.

[0035] Example 5 The embodiment provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, and the difference from the embodiment 1 is that Mo:N:C=30%:5%:65% in S1.

[0036] Example 6 The embodiment provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, and the difference from the embodiment 1 is that S1 uses D 50 =200nm of 5g carbon nanotubes+5g graphene.

[0037] Embodiment 7 The embodiment provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, and the difference from the embodiment 1 is that Co:Mn=1:1 in S2.

[0038] Embodiment 8 The embodiment provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, and the difference from the embodiment 1 is that S4 is adjusted to be first treated at 750 DEG C for 1h in 5% H2 / Ar, and then treated at 900 DEG C for 0.5h in N2.

[0039] Comparative Example 1 The comparative example provides a preparation method of a platinum-cobalt-manganese alloy catalyst, comprising the following steps: S1, 10g carbon black is directly added into an acetate solution with Co:Mn=3:1, and heat treatment is performed at 800 DEG C for 2h in argon; S2, heated at 135 DEG C for 6h; S3, treated at 600 DEG C for 1h in 5% H2 / Ar, and treated at 1000 DEG C for 2h in nitrogen; S4, treated with 1M sulfuric acid for 48h to obtain the catalyst (Pt:Co:Mn=100:25:8, alloy / support=55:45).

[0040] Comparative Example 2 The comparative example provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, and the difference from the embodiment 1 is that Mo:C=0.5%:99.5% in S1.

[0041] Comparative Example 3 The comparative example provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, and the difference from the embodiment 1 is that the final alloy / support=65:35.

[0042] Comparative Example 4 The comparative example provides a preparation method of a molybdenum-doped platinum-cobalt-manganese alloy catalyst, and the difference from the embodiment 1 is that S4 is changed to direct treatment at 800 DEG C for 3h in N2.

[0043] The molybdenum-doped platinum-cobalt-manganese alloy catalysts obtained by the methods of the embodiment 1-8 and the comparative examples 1-4 are subjected to performance test, the electrical performance test standard is an electrical catalyst test method in GB / T20042.4-2009, and the results are shown in Table 1.

[0044] Table 1 Through the comparative analysis of the above test data, the following conclusions can be drawn: (1) The key performance indicators such as mass activity, half-wave potential and ECSA loss rate in examples 1-8 are significantly better than those in comparative examples 1-4, indicating that the application significantly improves the oxygen reduction activity, stability and durability of the catalyst by using molybdenum doping technology, optimizing the carrier design and step-by-step heat treatment process.

[0045] (2) From comparative example 1 and examples 2-5, it can be seen that the mass activity of example 4 decreases by 29% and the half-wave potential decreases by 0.07V due to the molybdenum content of only 0.1at%; although the stability of example 5 is improved, the activity decreases slightly, and when the molybdenum content is 0.1at%, the indicators are significantly deteriorated, and when the molybdenum content is 5at%, the carrier conductivity is affected, indicating that the preferred molybdenum doping range of 1.5-4.5at% can achieve the best performance balance.

[0046] (3) From comparative example 1 and example 6, it can be seen that the use of carbon nanotube and graphene composite carrier can reduce the alloy particle size to 3.9nm, increase the mass activity to 0.48A / mgPt, and increase the specific surface area by 19%, proving that the multi-dimensional carbon carrier synergistic effect can significantly improve the catalyst dispersion.

[0047] (4) From comparative example 1 and example 7, it can be seen that when the CoMn ratio is adjusted to 1:1, the mass activity only decreases by 4.4%, indicating that the CoMn ratio range allowed by the application has good process tolerance.

[0048] (5) From comparative example 1 and example 8, it can be seen that reducing the high-temperature heat treatment temperature will cause the alloy particle size to increase by 13% and the mass activity to decrease by 8.9%, confirming the key role of 1100℃ high-temperature treatment in forming a high-order crystal structure.

[0049] (6) From comparative example 1 and comparative examples 1-2, it can be seen that when there is no molybdenum doping or the molybdenum content is insufficient, the ECSA loss rate of the catalyst increases by more than 40%, and the half-wave potential decreases by 0.08-0.10V, proving that molybdenum doping is a necessary condition for improving stability.

[0050] (7) From comparative example 1 and comparative example 3, it can be seen that when the alloy loading exceeds 60%, the alloy particle size increases sharply to 8.1nm and the mass activity decreases by 33%, verifying the scientificity of the preferred loading range of 50-55% in the application.

[0051] (8) From comparative example 1 and comparative example 4, it can be seen that canceling the step-by-step heat treatment process will cause the alloy particle size to increase by 73% and the mass activity to decrease by 26.7%, indicating that the synergistic effect of hydrogen-argon mixed gas pretreatment and inert gas high-temperature treatment cannot be replaced.

[0052] The molybdenum-doped platinum cobalt manganese alloy catalyst of the present application significantly improves the oxygen reduction activity and durability of the catalyst by constructing a synergistic structure of molybdenum oxide modified nitrogen-doped carbon composite carrier and ordered alloy core, combining an optimized step-by-step heat treatment process and controllable dealloying treatment. Among them, molybdenum doping not only enhances the metal carrier interaction, effectively inhibits the agglomeration of platinum alloy particles and the dissolution of transition metals, but also realizes the synergistic optimization of reaction mass transfer process and electronic structure through the formation of a unique structure of a platinum-rich surface and a molybdenum-doped core. The preparation method precisely controls the molybdenum content, alloy component ratio and heat treatment parameters, so that the catalyst exhibits excellent stability while maintaining high activity.

[0053] The above is only a preferred embodiment of the present application, not any form of limitation on the present application, although the present application has been disclosed as above with a preferred embodiment, however, not to limit the present application, any person skilled in the art, without departing from the scope of the technical scheme of the present application, can make some changes or modifications of the equivalent embodiments with the above disclosed technical content, but as long as it does not deviate from the technical scheme content of the present application, any concise modification, equivalent change and modification of the above embodiments according to the technical essence of the present application are still within the scope of the technical scheme of the present application.

Claims

1. A method for preparing a molybdenum-doped platinum-cobalt-manganese alloy catalyst, characterized in that: The preparation method comprises the following steps: S1. The carbon support was adsorbed by adding ammonium molybdate solution, filtered and dried, and then heat-treated in an inert gas to obtain a composite support MoO z / C x N y , after dispersion, dispersion A is obtained; S2. The composite support MoO z / C x N y After dispersion, cobalt salt and manganese salt solutions are added to form a slurry, which is treated at 60°C for 6-12 hours and heat-treated at 600-900°C in an inert gas atmosphere to obtain composite material B; S3. The composite material B was prepared into an ethylene glycol dispersion, a chloroplatinic acid solution was added, and the mixture was heated at 135°C for 6-10h to obtain a composite material C; S4. The composite material C was treated in a hydrogen-argon mixture at 750-800 ° C for 1-2h, and then in an inert gas at 900-1100 ° C for 0.5-1.5h to obtain a composite material D; S5. The composite material D was dealloyed in 1-2 M sulfuric acid at 80° C. for 48 h to obtain the molybdenum-doped platinum-cobalt-manganese alloy catalyst.

2. The method according to claim 1, characterized in that The mass ratio of Mo:N:C in the composite support obtained in step S1 is (1-30):(0.5-5):(65-98.5).

3. The method according to claim 1 or 2, characterized in that The carbon carrier in step S1 is selected from at least one of carbon black, activated carbon, carbon fiber, multi-walled carbon nanotubes, graphene, and conductive graphite, and the particle size D 50 10nm-20μm.

4. The method according to any one of claims 1 to 3, characterized in that In step S2, the molar ratio of the cobalt salt to the manganese salt is Co:Mn=(1-3):1, and the cobalt salt and the manganese salt are acetates.

5. The method according to any one of claims 1 to 4, characterized in that The total time of the two heat treatments in step S4 is 1.5-3.5 hours.

6. The method according to any one of claims 1 to 5, characterized in that The mass ratio of the alloy component to the composite carrier in the final molybdenum-doped platinum-cobalt-manganese alloy catalyst is (20-60):(40-80).

7. The method according to any one of claims 1 to 6, characterized in that The final atomic ratio of Mo:Pt:Co:Mn in the molybdenum-doped platinum-cobalt-manganese alloy catalyst is (0.01-5):100:(0.01-35):(0.01-35).

8. The method according to claim 7, characterized in that The atomic ratio of Mo:Pt:Co:Mn is (1.5-4.5):100:(15-30):(8-15).

9. The method according to any one of claims 1 to 8, characterized in that The composite support MoO z / C x N y The atomic ratio of Mo to O is 100:(1-200).

10. A molybdenum-doped platinum-cobalt-manganese alloy catalyst prepared by the method of any one of claims 1 to 9, wherein the general structural formula is Mo-doped PtCoMn / MoO z @C x N y The platinum-based alloy nanoparticles are 2-10 nm in size and are uniformly loaded on MoO z modified nitrogen-doped carbon supports.

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