阅读说明：本技术 一种燃料电池铂基合金催化剂的制备方法 (Preparation method of fuel cell platinum-based alloy catalyst ) 是由 刘建国 李晓克 李佳 曹峰 段骁 于 2021-08-11 设计创作，主要内容包括：本发明公开了一种燃料电池铂基合金催化剂的制备方法,包括以下步骤：(1)将至少含有钴盐的金属盐溶解后,加入氨水或含有氨基基团的小分子和碱,形成溶胶；(2)将所述溶胶进行微波加热；(3)将加热后的溶胶与含铂催化剂混合后干燥,并进行退火处理,经酸洗、干燥后得到所述铂合金催化剂。本发明方法具有制备快速、简易、方便的特点,便于批量化及大规模生产。同时,本发明制备得到的铂钴合金催化剂粒径均匀,催化性能高,适用于燃料电池中的氧还原反应催化剂。(The invention discloses a preparation method of a platinum-based alloy catalyst of a fuel cell, which comprises the following steps: (1) dissolving metal salt at least containing cobalt salt, and adding ammonia water or micromolecule containing amino group and alkali to form sol; (2) microwave heating the sol; (3) and mixing the heated sol with a platinum-containing catalyst, drying, annealing, pickling and drying to obtain the platinum alloy catalyst. The method has the characteristics of quick, simple and convenient preparation, and is convenient for batch and large-scale production. Meanwhile, the platinum-cobalt alloy catalyst prepared by the method has uniform particle size and high catalytic performance, and is suitable for an oxygen reduction reaction catalyst in a fuel cell.)

1. A preparation method of a fuel cell platinum-based alloy catalyst is characterized by comprising the following steps:

(1) dissolving metal salt at least containing cobalt salt, and adding ammonia water or micromolecule containing amino group and alkali to form sol;

(2) microwave heating the sol;

(3) mixing the heated sol with a platinum-containing catalyst, drying, annealing, acid washing and drying to obtain the catalyst.

2. The method for preparing the platinum-based alloy catalyst for the fuel cell as recited in claim 1, wherein in the step (2), the microwave heating power is 500-1000W and the time is 1-180 min.

3. The method for preparing a platinum-based alloy catalyst for a fuel cell according to claim 1, wherein in the step (3), the mass ratio of cobalt in the sol to platinum in the platinum-containing catalyst is 1: 1-10: 1.

4. the method for preparing a platinum-based alloy catalyst for a fuel cell according to claim 1, wherein in the step (1), the metal salt further includes a metal salt having at least one cation of Fe, Co, Ni, Cu, Mn, V, W, or Ce in addition to the cobalt salt.

5. The method for preparing a platinum-based alloy catalyst for a fuel cell according to claim 1, wherein in the step (1), the metal salt includes at least one of a nitrate, an acetate, a halide, a complex, or an acetylacetonate.

6. The method for preparing a platinum-based alloy catalyst for a fuel cell according to claim 1, wherein the platinum-containing catalyst in the step (3) has a platinum loading of 5 to 100% by mass.

7. The method for preparing a platinum-based alloy catalyst for a fuel cell according to claim 1, wherein in the step (3), the annealing temperature is 150-800 ℃, and the annealing time is 1-6 h.

8. The method for preparing a platinum-based alloy catalyst for a fuel cell according to claim 1, wherein the solvent in step (1) is water and/or ethanol.

9. The method for preparing a platinum-based alloy catalyst for a fuel cell according to claim 1, wherein the mass fraction of the aqueous ammonia in the step (1) is 1 to 30%.

10. The method for producing a platinum-based alloy catalyst for a fuel cell according to claim 1, wherein the platinum-based alloy catalyst finally produced in the step (3) is at least one of PtCo, PtCoFe, PtCoNi, PtCoCu, PtCoMn, PtCoCe, PtCoV, and PtCoW.

Technical Field

The invention relates to a preparation method of an alloy catalyst, in particular to a preparation method of a fuel cell platinum-based alloy catalyst.

Background

The hydrogen energy technology is one of the key technologies for carbon reduction and is also the key of the competition of a new technological revolution and an industrial revolution. The fuel cell technology, especially the proton exchange membrane fuel cell, is widely used in the transportation field, the power supply field and the portable power source field as a core technology of the hydrogen energy industry, and is generally regarded as one of key technologies for solving the future human energy crisis. However, the catalyst is still mainly platinum at present. In order to further reduce the cost and reduce the usage amount of the platinum catalyst, Pt and other transition metals, such as transition metal elements of Fe, Co, Ni, etc., are usually alloyed, so as to improve the performance of the catalyst by virtue of a ligand effect and a stress effect and reduce the usage amount of Pt. The two effects can shift the center of gravity of the d-band of the Pt atom downwards, weaken the binding energy of the Pt and the oxygen-containing intermediate and improve the catalytic activity.

At present, the common high-activity catalyst is a Pt-based alloy catalyst. However, the fuel cell has harsh operating conditions, and under high voltage (0.6-1.0V) and strong acid operating conditions, the transition metal in the catalyst is easily oxidized and dissolved and lost, so that the ligand effect and the stress effect brought by alloying disappear, and the catalytic activity is reduced. The dissolved ions may have the action of attacking the proton membrane, so that the service life of the membrane electrode is reduced in the later application, and it is reported that the corrosion of the membrane caused by free radicals can be effectively eliminated by using the additive taking Mn, Ce and other elements as the proton membrane, so that the service life of the membrane electrode is prolonged. Therefore, controllable preparation of the high-efficiency and stable multi-element alloy catalyst with functional function is very important for the development of fuel cell technology.

The general method for preparing the platinum-based alloy catalyst is to mix precursor salts in an organic solvent and obtain the platinum-based alloy catalyst by controlling the reduction process. However, synthesis is difficult due to the large difference in reduction potential between Pt ions and transition metal ions. In addition, the organic solvent is adsorbed on the surface of the catalyst, and removal is difficult. Soderberg et al annealed a cobalt sol mixed with a Pt catalyst to give a Pt/Co catalyst (Journal of Electrochemistry, Vol.152(10): A2017-A2022). However, the preparation process of the sol is complex, so that the performance of the catalyst is not obviously improved, and the catalyst is not widely used. Sun et al prepared transition metal oxide nanoparticles (publication No. CN 104709882A) using amino group-containing small molecular bases or basic solvents. However, the preparation process of the method can generate certain precipitates, and the stability of the precursor solution is poor. The heating time is long, the steps are complicated, and the rapid production is not facilitated.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a preparation method of a fuel cell platinum-based alloy catalyst which has high and stable catalytic performance and is beneficial to rapid production.

The technical scheme is as follows: the preparation method of the platinum-based alloy catalyst for the fuel cell comprises the following steps:

(1) dissolving metal salt at least containing cobalt salt, and adding ammonia water or micromolecule containing amino group and alkali to form sol;

(2) microwave heating the sol;

(3) and mixing the heated sol with a platinum-containing catalyst, drying, annealing, pickling and drying to obtain the platinum alloy catalyst.

Preferably, in the step (2), the power of the microwave heating is 500-. If the power is too high, the solution is easy to explode due to the low boiling point of the solvent, certain danger exists, meanwhile, condensation is difficult, and the concentration in the precursor solution is difficult to ensure; if the power is too low, the heating rate is slow, and it is difficult to ensure that the particle size of the precursor to be produced is small and uniform.

Preferably, in the step (1), the metal salt further includes a metal salt having at least one cation of Fe, Co, Ni, Cu, Mn, V, W, or Ce in addition to the cobalt salt.

Preferably, in step (1), the metal salt comprises at least one of a nitrate, an acetate, a halide, a complex or an acetylacetonate.

Preferably, the platinum loading in the platinum-containing catalyst is 5-100% by mass. If the loading amount is too low, it is difficult for platinum and the precursor to form good interfacial bonding, and thus it is difficult to form an alloy in the subsequent thermal annealing process.

Preferably, in the step (3), the mass ratio of cobalt in the sol to platinum in the platinum-containing catalyst is 1: 1-10: 1; the annealing temperature is 150-800 ℃, and the annealing time is 1-6 h. If the annealing temperature is too high, the precursor can catalyze the oxidation of the carbon carrier, so that the catalyst carrier is damaged, and the catalyst loses stable support to form agglomeration; if the amount is too low, the driving force for diffusion of atoms at the interface is insufficient, and effective alloying is difficult.

Preferably, in the step (3), the annealing atmosphere is nitrogen, argon or a hydrogen-argon mixed gas.

Preferably, in step (1), the solvent is water and/or ethanol.

Preferably, in the step (1), the mass fraction of the ammonia water is 1-30%. If the mass fraction is too high, too high basicity may cause the platinum to be detached from the carrier during the mixing of the platinum catalyst, resulting in particle agglomeration; if the amount is too low, it is difficult to form a stable coordination effect with cobalt ions, and a stable precursor cannot be obtained.

Preferably, the fuel cell platinum-based alloy catalyst is at least one of PtCo, PtCoFe, PtCoNi, PtCoCu, PtCoMn, PtCoCe, PtCoV, and PtCoW.

Firstly, preparing a precursor of cobalt or other doped metal elements, utilizing the interaction between the surface of an oxide and the surface of platinum, and in the thermal annealing process, the surface segregation of the platinum and transition metal is utilized, and atoms are diffused at the interface to form platinum alloy. Due to the adoption of a microwave heating method, the heating is uniform, the heating speed is high, the nucleation can be quickly carried out in a short time, and the precursor containing cobalt with a small size can be obtained. The obtained precursor has stable property and batch advantage. Meanwhile, surface atoms are more unstable due to the size of the precursor, have high surface energy, and are more prone to migration and diffusion under the action of thermal driving, so that more stable alloy components are formed.

Compared with the traditional alloy catalyst synthesis method, the method has the advantages that by means of the complexation of ammonia radicals to transition metals and the principle of microwave heating, the small-size precursor rich in oxygen defects is obtained by quickly heating, and the problems of particle growth and agglomeration caused by long-time heating are avoided. According to the invention, the carbon-supported platinum nanoparticles and the transition metal precursor are mixed, and the alloy catalyst with high activity is formed by virtue of the atomic diffusion effect at the interface, so that the problem of large reduction potential difference between platinum and transition metal ions is solved. In addition, the small size of the precursor may serve to limit agglomeration of the platinum particles. Meanwhile, the solvent is ethanol, so that the method is low in toxicity and harmless, and can be recycled through condensation, thereby increasing the economy of the method.

Has the advantages that: compared with the prior art, the invention has the following remarkable effects: 1. the catalytic performance prepared by the method is efficient and stable, the method is favorable for rapid production, and compared with the traditional method for chemically synthesizing the platinum-based alloy catalyst, the method is not limited by the reduction potential of ions and has stronger universality; 2. the process is simple, a surfactant and a complex solvent system are not needed, the method can be used for large-scale production, and the large-scale production of products is facilitated; 3. the method can be used as a post-treatment method for improving the performance of the platinum catalyst, and the method can be used for modifying the catalyst, so that the catalytic performance of the catalyst can be obviously improved.

Drawings

FIG. 1 is a schematic view of a preparation process of the present invention;

FIG. 2 is a graph comparing the ORR of the catalysts prepared in examples 1, 2, 3 with commercial 20% platinum carbon;

FIG. 3 is a TEM image of a commercial platinum on carbon and a catalyst prepared in example 3;

FIG. 4 is an XRD spectrum of the catalysts prepared in examples 1, 2 and 3;

FIG. 5 is a comparative ORR chart of catalysts prepared in examples 4, 5, 6, 7, 8, 9, 10;

FIG. 6 is a graph of the ORR performance of the catalyst prepared in example 11;

FIG. 7 is a graph comparing ORR of catalysts prepared in examples 12, 13, 14, and 15;

FIG. 8 is a comparative ORR chart of the catalysts prepared in comparative examples 1, 2, 3, 4 and example 3.

Detailed Description

The invention is described in further detail below with reference to the drawings.

Example 1

Adding 0.4g of cobalt acetate tetrahydrate into 50mL of ethanol, stirring until the cobalt acetate tetrahydrate is dissolved, adding 3mL of concentrated ammonia water solution with the mass fraction of 28%, and placing the mixture in a containerStirring in air until the solution color turns to dark brown, transferring the solution into a microwave reactor, heating at 500W for 30min, mixing the obtained precursor with commercial platinum carbon with platinum content of 20% in 200mg, heating, drying, and annealing at 200 deg.C for 4H in H atmosphere₂and/Ar, the mass fraction of hydrogen is 5%.

Example 2

Adding 0.4g of cobalt acetate tetrahydrate into 50mL of ethanol, stirring until the cobalt acetate tetrahydrate is dissolved, adding 3mL of a concentrated ammonia water solution with the mass fraction of 28%, placing the solution into air, stirring until the color of the solution is dark brown, transferring the solution into a microwave reactor, heating for 30min at the heating power of 500W, uniformly mixing the obtained precursor with commercial platinum carbon with the mass loading of 20% of 200mg of platinum, heating and drying, and annealing at 400 ℃ for 4H in the annealing atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Example 3

Adding 0.4g of cobalt acetate tetrahydrate into 50mL of ethanol, stirring until the cobalt acetate tetrahydrate is dissolved, adding 3mL of a concentrated ammonia water solution with the mass fraction of 28%, placing the solution into air, stirring until the color of the solution is dark brown, transferring the solution into a microwave reactor, heating for 30min at the heating power of 500W, uniformly mixing the obtained precursor with commercial platinum carbon with the mass loading of 20% of 200mg of platinum, heating and drying, and annealing at 600 ℃ for 4H in the annealing atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Example 4

Adding 0.4g of cobalt acetate tetrahydrate and 0.04g of iron acetylacetonate into 50mL of ethanol, stirring uniformly, adding 3mL of 28 mass percent concentrated ammonia water solution, stirring in air until the solution becomes dark brown, transferring the solution into a microwave reactor, heating for 30min at 500W of heating power, uniformly mixing the obtained precursor with commercial platinum carbon with the mass capacity of 20% of 200mg of platinum, heating and drying, and annealing at 400 ℃ for 4H under the annealing atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Example 5

To 50mL of ethanol were added 0.4g of cobalt acetate tetrahydrate and 0.04g of chlorineNickel is dissolved, after the mixture is stirred to be uniform, 3mL of concentrated ammonia water solution with the mass fraction of 28 percent is added, the mixture is placed in air and stirred until the color of the solution is changed into dark brown, the solution is transferred to a microwave reactor, the solution is heated for 30min with the heating power of 500W, the obtained precursor is uniformly mixed with commercial platinum carbon with the mass loading of 20 percent of 200mg of platinum, the annealing is carried out for 4H at the temperature of 400 ℃ after the heating and the drying, and the annealing atmosphere is H₂and/Ar, the mass fraction of hydrogen is 5%.

Example 6

Adding 0.4g of cobalt acetate tetrahydrate and 0.04g of copper sulfate into 50mL of ethanol, stirring uniformly, adding 3mL of a 28% concentrated ammonia water solution, stirring in air until the solution becomes dark brown, transferring the solution into a microwave reactor, heating for 30min at 500W of heating power, uniformly mixing the obtained precursor with commercial platinum and carbon with the platinum mass capacity of 20% of 200mg, heating and drying, and annealing at 400 ℃ for 4H under the annealing atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Example 7

Adding 0.4g of cobalt acetate tetrahydrate and 0.05g of manganese acetate into 50mL of ethanol, stirring uniformly, adding 3mL of 28 mass percent concentrated ammonia water solution, stirring in air until the solution color becomes dark brown, transferring the solution into a microwave reactor, heating for 30min at 500W of heating power, uniformly mixing the obtained precursor with commercial platinum carbon with the platinum mass capacity of 20 percent of 200mg, heating and drying, and annealing at 400 ℃ for 4H under the annealing atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Example 8

Adding 0.4g of cobalt acetate tetrahydrate and 0.04g of ammonium ceric nitrate into 50mL of ethanol, stirring uniformly, adding 3mL of 28 mass percent concentrated ammonia water solution, stirring in air until the solution becomes dark brown, transferring the solution into a microwave reactor, heating for 30min at 500W of heating power, uniformly mixing the obtained precursor with commercial platinum carbon with the mass capacity of 20% of 200mg of platinum, heating and drying, and annealing at 400 ℃ for 4H under the annealing atmosphere of H₂and/Ar, wherein the mass fraction of hydrogen is 10%.

Example 9

Adding 0.4g of cobalt acetate tetrahydrate and 0.04g of vanadium chloride into 50mL of ethanol, stirring until the cobalt acetate tetrahydrate and the vanadium chloride are dissolved, adding 3mL of a 28 mass percent concentrated ammonia water solution, stirring in air until the solution becomes dark brown, transferring the solution into a microwave reactor, heating for 30min at 500W of heating power, uniformly mixing the obtained precursor with commercial platinum carbon with the mass capacity of 20% of 200mg of platinum, heating and drying, and annealing at 400 ℃ for 4H under the annealing atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Example 10

Adding 0.4g of cobalt acetate tetrahydrate and 0.04g of tungsten hexacarbonyl into 50mL of ethanol, stirring until the cobalt acetate tetrahydrate and the tungsten hexacarbonyl are dissolved, adding 3mL of a 28 mass percent concentrated ammonia water solution, stirring in air until the solution becomes dark brown, transferring the solution into a microwave reactor, heating for 30min at 500W of heating power, uniformly mixing the obtained precursor with commercial platinum-carbon with the mass capacity of 20% of 200mg of platinum, heating and drying, and annealing at 400 ℃ for 6H under the annealing atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Example 11

Adding 0.2g of cobalt acetate tetrahydrate into 50mL of ethanol, stirring until the cobalt acetate tetrahydrate is dissolved, adding 2mL of a concentrated ammonia water solution with the mass fraction of 28%, placing the solution in air, stirring until the color of the solution is dark brown, transferring the solution into a microwave reactor, heating for 30min at the heating power of 500W, uniformly mixing the obtained precursor with a commercial platinum-cobalt-carbon catalyst with the mass loading of 200mg of platinum being 20%, heating and drying, and annealing at 400 ℃ for 4H in the annealing atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Example 12

Adding 0.4g of cobalt acetate tetrahydrate and 0.04g of iron acetylacetonate into 50mL of ethanol, stirring uniformly, adding 3mL of a 28% concentrated ammonia water solution, stirring in the air until the solution becomes dark brown, transferring the solution into a microwave reactor, heating for 30min at 500W of heating power, uniformly mixing the obtained precursor with a platinum-carbon catalyst with the platinum mass capacity of 5%, heating and drying, and annealing at 600 ℃ for 2h under the condition that the annealing atmosphere is nitrogen.

Example 13

Adding 0.4g of cobalt acetate tetrahydrate and 0.04g of nickel chloride into 50mL of ethanol, stirring uniformly, adding 3mL of a 28% concentrated ammonia water solution, stirring in air until the solution becomes dark brown, transferring the solution into a microwave reactor, heating for 30min at 500W of heating power, uniformly mixing the obtained precursor with a platinum-carbon catalyst with the platinum mass capacity of 5%, heating and drying, and annealing at 600 ℃ for 2h under the condition that the annealing atmosphere is nitrogen.

Example 14

Adding 0.4g of cobalt acetate tetrahydrate and 0.04g of copper sulfate into 50mL of ethanol, stirring until the mixture is uniform, adding 3mL of a concentrated ammonia water solution with the mass fraction of 28%, placing the mixture into air, stirring until the solution becomes dark brown, transferring the solution into a microwave reactor, heating for 30min at the heating power of 500W, uniformly mixing the obtained precursor with a platinum-carbon catalyst with the platinum mass capacity of 5% of 200mg, heating and drying, and annealing at 600 ℃ for 2h, wherein the annealing atmosphere is nitrogen.

Example 15

Adding 0.4g of cobalt acetate tetrahydrate and 0.05g of manganese acetate into 50mL of ethanol, stirring until the mixture is uniform, adding 3mL of a concentrated ammonia water solution with the mass fraction of 28%, placing the mixture into air, stirring until the color of the solution becomes dark brown, transferring the solution into a microwave reactor, heating for 30min at the heating power of 500W, uniformly mixing the obtained precursor with a platinum-carbon catalyst with the mass loading of 200mg of platinum being 5%, heating and drying, and annealing at 600 ℃ for 2h, wherein the annealing atmosphere is nitrogen.

Example 16

Adding 0.0045g of cobalt acetate tetrahydrate into 50mL of ethanol, stirring uniformly, adding 3mL of concentrated ammonia water solution with the mass fraction of 1%, placing in air, stirring until the solution color becomes dark brown, transferring the solution into a microwave reactor, heating for 1min at the heating power of 500W, uniformly mixing the obtained precursor with 100mg of platinum-carbon catalyst with the mass loading of 1%, heating and drying, and annealing for 2h at 800 ℃, wherein the annealing atmosphere is nitrogen.

Example 17

Adding 8.85g of cobalt acetate tetrahydrate into 50mL of ethanol, stirring until the mixture is uniform, adding 10mL of concentrated ammonia water solution with the mass fraction of 30%, placing the mixture into air, stirring until the solution becomes dark brown, transferring the solution into a microwave reactor, heating for 180min at the heating power of 1000W, and uniformly mixing the obtained precursor with 177mg of platinum black catalyst, wherein the platinum content is 100%; heating, drying, and annealing at 150 deg.C for 6 hr in H atmosphere₂and/Ar, wherein the mass fraction of hydrogen is 1%.

Example 18

Adding 0.4g of cobalt acetate tetrahydrate into 50mL of ethanol, stirring until the cobalt acetate tetrahydrate is dissolved, adding a mixed solution of ammonium chloride and sodium hydroxide, placing the mixed solution into air, stirring until the color of the solution is dark brown, transferring the solution into a microwave reactor, heating for 30min at the heating power of 500W, uniformly mixing the obtained precursor with commercial platinum-carbon with the platinum mass capacity of 20%, heating and drying, and annealing at 200 ℃ for 4H under the annealing atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Example 19

Adding 0.4g of cobalt acetate tetrahydrate into 50mL of water, stirring until the cobalt acetate tetrahydrate is dissolved, adding a mixed solution of ammonium chloride and sodium hydroxide, placing the mixed solution into air, stirring until the solution color is dark brown, transferring the solution into a microwave reactor, heating for 30min at the heating power of 500W, uniformly mixing the obtained precursor with commercial platinum-carbon with the platinum mass capacity of 20% of 200mg, heating and drying, and annealing at 600 ℃ for 4H in an annealing atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Example 20

Adding 0.4g of cobalt acetate tetrahydrate into 50mL of mixed solvent with water and ethanol in a mass ratio of 1:1, stirring until the cobalt acetate tetrahydrate is dissolved, adding mixed solution of ammonium chloride and sodium hydroxide, stirring in air until the solution color becomes dark brown, transferring the solution into a microwave reactor, heating for 30min at 500W of heating power, uniformly mixing the obtained precursor with commercial platinum carbon with the mass capacity of 20% of 200mg of platinum, and heating to dryAfter drying, annealing for 4 hours at 600 ℃ in the atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Comparative example 1

Adding 0.4g of cobalt acetate tetrahydrate into 50mL of ethanol, stirring until the cobalt acetate tetrahydrate is dissolved, adding a mixed solution of ammonium chloride and sodium hydroxide, placing the mixed solution into air, stirring until the solution color becomes dark brown, uniformly mixing the dark brown mixed solution with commercial platinum carbon with the mass capacity of 20% of 200mg of platinum, heating and drying, and annealing at 600 ℃ for 4 hours in an annealing atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Comparative example 2

Adding 0.4g of cobalt acetate tetrahydrate into 50mL of ethanol, stirring until the cobalt acetate tetrahydrate is dissolved, adding a mixed solution of ammonium chloride and sodium hydroxide, placing the mixed solution into air, stirring until the color of the solution is dark brown, transferring the solution into a microwave reactor, heating for 480min at the heating power of 100W, uniformly mixing the obtained precursor with commercial platinum carbon with the platinum mass capacity of 20%, heating and drying, and annealing at 600 ℃ for 4H in an annealing atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Comparative example 3

Adding 0.4g of cobalt acetate tetrahydrate into 50mL of ethylene glycol, stirring until the cobalt acetate tetrahydrate is dissolved, adding 3mL of a concentrated ammonia water solution with the mass fraction of 28%, placing the solution in air, stirring until the color of the solution is dark brown, transferring the solution into a microwave reactor, heating for 60min at the heating power of 500W, uniformly mixing the obtained precursor with commercial platinum carbon with the mass loading of 20% of platinum, drying, and annealing at 600 ℃ for 4H in the annealing atmosphere of H₂and/Ar, the mass fraction of hydrogen is 5%.

Comparative example 4

Adding 0.4g of cobalt acetate tetrahydrate into 50mL of ethanol, stirring until the cobalt acetate tetrahydrate is dissolved, adding 3mL of a concentrated ammonia water solution with the mass fraction of 28%, placing the solution in air, stirring until the solution becomes dark brown, transferring the solution into a microwave reactor, heating for 60min at the heating power of 500W, uniformly mixing the obtained precursor with a platinum-carbon catalyst with the platinum mass loading of 2%, drying, and annealing at 600 ℃ for 4H in the annealing atmosphere of H₂Ar, mass of hydrogenThe fraction was 5%.

The preparation process of the invention is schematically shown in figure 1. Fig. 2 is a graph comparing the ORR of the catalysts prepared in examples 1, 2, 3 with commercial 20% platinum carbon, and it can be seen from fig. 1 that the resulting PtCo catalytic ORR performance is increasing with increasing annealing temperature. It is shown that the increase of annealing temperature can promote the diffusion of atoms and obtain a catalyst with better performance.

Fig. 3 is a TEM image of a commercial platinum on carbon and the catalyst prepared in example 3, and from fig. 3 it can be seen that after treatment, the resulting PtCo nanoparticles did not increase significantly in size compared to the original Pt catalyst, while no significant agglomeration occurred. The precursor particles can limit the migration and diffusion of the Pt nanoparticles at high temperature, and agglomeration is avoided.

Fig. 4 is an XRD spectrum of the catalysts prepared in examples 1, 2 and 3, and it can be seen from fig. 4 that the diffraction peak of the catalyst is shifted toward a high angle as the annealing temperature is increased. It is shown that an increase in the annealing temperature can promote the alloying of PtCo.

Fig. 5 is a graph comparing ORR of catalysts prepared in examples 4, 5, 6, 7, 8, 9 and 10, and it can be seen from fig. 5 that PtCoM three-way catalysts prepared from precursors doped with different elements have excellent ORR catalytic activity. The patent method has better universality and operability.

Fig. 6 is a graph of ORR performance of the catalyst prepared in example 11, and it can be seen from fig. 6 that the PtCo catalyst prepared has excellent ORR catalytic activity when the precursor concentration is reduced. The precursor concentration has little influence on the performance of the obtained PtCo catalyst and is more relevant to the annealing temperature.

Figure 7 is a graph comparing the ORR of the catalysts prepared in examples 12, 13, 14, 15, and it can be seen from figure 7 that the PtCoM three-way catalyst prepared from the different element doped precursors and the low platinum loading catalyst has an ORR catalytic activity exceeding that of the 20% platinum carbon catalyst. The patent method has better universality and operability.

Fig. 8 is a graph comparing ORR of the catalysts prepared in comparative examples 1, 2, 3, 4 and example 3, and it can be seen from fig. 8 that whether microwave heating is performed or not, the heating time, the type of solvent and the platinum loading of the platinum catalyst all affect the catalytic performance of the obtained PtCo catalyst.