A method for preparing a carbon-supported core-shell platinum-nickel catalyst for proton exchange membrane fuel cells.

Abstract

This invention relates to a method for preparing a carbon-supported core-shell platinum-nickel catalyst for proton exchange membrane fuel cells. The method involves thoroughly impregnating a carbon support with nickel salt and palladium nitrate, adjusting the pH of the impregnation solution with sodium hydroxide to obtain a precursor solution for preparing the nickel core, transferring it to a reactor, heating it to 120-180°C, and introducing hydrogen gas for a first pressurized hydrogen reduction to obtain carbon-supported nickel nanoparticles. Subsequently, the carbon-supported nickel nanoparticles are mixed with a platinum nitrate solution, and the solution pH is adjusted with ammonia water for a second impregnation and ultrasonic stirring. The mixture is then transferred to a reactor, heated to 40-90°C, and introduced hydrogen gas for a second pressurized hydrogen reduction to obtain the carbon-supported core-shell platinum-nickel catalyst product. The mass activity of the core-shell platinum-nickel catalyst prepared by this invention exceeds 0.70 A·mg. Pt ‑1 It is superior to the 0.25 A·mg of mainstream platinum-carbon catalysts currently on the market. Pt ‑1 .

Description

Technical Field

[0001] This invention relates to a method for preparing a carbon-supported core-shell structured platinum-nickel catalyst for proton exchange membrane fuel cells, and belongs to the field of catalyst preparation. Background Technology

[0002] In recent years, proton exchange membrane fuel cells (PEMFCs) have directly converted the chemical energy of fuel into electrical energy, possessing advantages such as high energy conversion efficiency, low operating temperature, and no pollution, and are considered one of the most ideal energy sources currently available. Core-shell structured catalysts have stood out among numerous platinum-based bimetallic catalysts due to their high performance and high stability, becoming a research focus of considerable interest. When using transition metals (Ni, Co, Cu, etc.) as the core, the surface platinum nanoshell can ensure high activity while reducing the amount of Pt used. Various platinum-coated core-shell structures can be prepared through crystal growth, dealloying, electrochemical deposition, and thermal treatment methods (Liu Hangcheng, Tao Zeyu, Liu Jianfeng, Shi Zhengrong. Research progress of Pt-based catalysts in PEMFCs [J]. Battery, 2024, 1-4). Among these methods, the most common preparation method for core-shell structured catalysts is to first prepare an alloy of Pt and a transition metal, and then use a dealloying method with acid treatment to dissolve the transition metal atoms in an acidic environment, thereby forming a core-shell structure. Gan et al. prepared core-shell Pt-Ni catalysts using a dealloying method. First, they used platinum acetylacetonate and nickel acetylacetonate as precursors, oleylamine and oleic acid as surfactants, and 1,2-tetradecanediol as a reducing agent to synthesize Pt. x -Ni 1－xNanoparticles were synthesized and dealloyed to produce catalysts with distinct core-shell structures and oxygen reduction reaction (ORR) catalytic activity (Gan L, Cui C, Rudi S, et al. Core Shell and Nanoporous Particle Architectures and Their Effect on the Activity and Stability of Pt ORR Electrocatalysts[J]. Topics in Catalysis, 2014, 57(1-4):236-244). However, the catalysts prepared by dealloying are structurally unstable, forming a relatively porous structure, which leads to the dissolution and loss of the transition metal element that serves as the core. Another commonly used preparation method is to synthesize elemental transition cores and then coat the surface of the transition metal core with a thin layer of Pt. F. Godl'nez-Salomo prepared Ni@Pt nanocatalysts by impregnation-NaBH4 reduction, and then subjected them to heat treatment in a hydrogen atmosphere, which caused strong segregation of the Ni remaining in the uppermost layer of the core-shell catalyst. After durability testing, the Ni in the uppermost layer of the catalyst dissolved (F. Godínez-Salomón, M. Hallen-López, Solorza-Feria O. Enhanced electroactivity for the oxygen reduction on Ni@Pt core-shell nanocatalysts[J]. International Journal of Hydrogen Energy, 2012, 37(19): 14902-14910). Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing a carbon-supported core-shell structured platinum-nickel catalyst for proton exchange membrane fuel cells with excellent electrochemical performance.

[0004] The preparation method of carbon-supported core-shell structured platinum-nickel catalyst for proton exchange membrane fuel cells, the specific process is as follows:

[0005] 1. Preparation of carbon-supported nickel nanoparticles

[0006] The nickel salt and palladium nitrate were completely dissolved in pure water, and then the carbon support was added to the solution to obtain a mixed solution. The mixed solution was then stirred and impregnated for 6-12 hours. Subsequently, the pH of the solution was adjusted to 9.0-11.5 using sodium hydroxide, and then ultrasonically treated to obtain a nickel-containing precursor solution.

[0007] The nickel concentration in the nickel-containing precursor solution is 0.1-2 g / L, the amount of palladium nitrate added is 0.03% to 0.16% of the nickel mass in the nickel-containing precursor solution, and the ratio of the total mass of platinum and nickel in the mixed solution to the mass of the carbon support is 1:4 to 100.

[0008] The nickel-containing precursor solution was transferred to a reactor, and a protective gas was introduced. When the volume fraction of oxygen at the reactor outlet was less than 0.1% as measured by an oxygen concentration tester, the outlet was closed, and the temperature was raised. When the temperature reached 120–180°C, hydrogen gas was introduced at a partial pressure of 1.5–3 MPa. The reaction was carried out for 60–120 minutes. When the temperature was lowered to below 50°C, a protective gas was introduced to replace the hydrogen gas. After the hydrogen gas was completely replaced, the reactor was opened, and the resulting solution was filtered and washed with pure water until neutral to obtain carbon-supported nickel nanoparticles.

[0009] 2. Platinum-loaded

[0010] The above-mentioned carbon-supported nickel nanoparticles and platinum nitrate were mixed to obtain a mixed slurry. Ammonia water was added dropwise to control the pH of the mixed slurry to 5.0-8.0. After a second stirring and soaking for 2-4 hours, ultrasonic stirring was continued for 2-6 hours to obtain a platinum-containing precursor solution.

[0011] In the mixed slurry, the molar ratio of platinum to nickel is 3 to 1:1, and the concentration of platinum in the mixed slurry is 0.30 to 10 g / L.

[0012] The adjusted platinum-containing precursor solution was transferred to a reactor, and a protective gas was introduced into the reactor. When the volume fraction of oxygen concentration at the reactor outlet was less than 0.1% as measured by an oxygen concentration meter, the outlet was closed, and the temperature was raised. When the temperature reached 40–90°C, hydrogen gas was introduced at a partial pressure of 0.3–0.8 MPa. After reacting for 30–90 minutes, the temperature was lowered to below 50°C, and the protective gas was introduced to replace the hydrogen. After the hydrogen replacement was complete, the reactor was opened, and the resulting solution was filtered, washed with ethanol, and dried under vacuum to obtain a core-shell structured platinum-nickel catalyst.

[0013] The ammonia solution is an analytical grade reagent of 25%–28%; the sodium hydroxide is an analytical grade reagent; the platinum nitrate is a platinum nitrate solution with a platinum mass concentration of 10%; the palladium nitrate is an analytical grade reagent of palladium nitrate dihydrate (palladium content ≥39wt%); the hydrogen gas has a purity of not less than 99.99%; the protective gas is nitrogen or argon with a purity of not less than 99.99%; the carbon is EC300J, EC600JD, or BP-2000; and the nickel salt is an analytical grade reagent of nickel nitrate hexahydrate or nickel sulfate hexahydrate.

[0014] This invention involves preparing a solution of nickel salt and palladium nitrate, then stirring and impregnating it with a carbon support to form a mixed solution. Sodium hydroxide is used to adjust the pH to prepare a nickel-containing precursor solution. This nickel-containing precursor solution is transferred to a reactor, where hydrogen is introduced for a first pressurized hydrogen reduction to produce carbon-supported nickel nanoparticles. Next, the carbon-supported nickel nanoparticles are mixed with a platinum nitrate solution. Ammonia is used to adjust the pH of the mixed slurry, followed by further impregnation and ultrasonic stirring to obtain a platinum-containing precursor solution. Finally, the platinum-containing precursor solution is transferred to a reactor, where hydrogen is introduced for a second pressurized hydrogen reduction to produce a carbon-supported core-shell structured platinum-nickel catalyst.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] (1) The carbon-supported core-shell platinum-nickel catalyst prepared in this invention exhibits excellent electrochemical performance, and the mass activity of the core-shell platinum-nickel catalyst prepared in this invention exceeds 0.70 A·mg. Pt -1 It is superior to the 0.25 A·mg of mainstream platinum-carbon catalysts currently on the market. Pt -1 ;

[0017] (2) In the process of preparing nickel cores, the present invention adds palladium nitrate to reduce the reaction temperature and hydrogen partial pressure of pressurized hydrogen reduction to prepare nano-nickel cores, which is beneficial to reduce nickel core agglomeration; on the other hand, it reduces the d-band center of the catalyst and increases oxygen reduction activity.

[0018] (3) Based on the formed carbon-supported nickel core, the present invention performs ultrasonic stirring and reduction to obtain the initial platinum shell, and then performs secondary pressurized hydrogen reduction to accelerate the formation of the platinum shell, which is beneficial to the complete coating of the nickel core by the platinum shell and increases the stability and durability of the catalyst.

[0019] (4) The present invention uses high-purity hydrogen as the reducing agent of the reaction system. No impurity elements are introduced during the reduction process, thus avoiding the influence of impurity elements on the performance of the catalyst. Attached Figure Description

[0020] Figure 1 This is a process flow diagram of the present invention.

[0021] Figure 2 This is the XRD pattern of the core-shell structure Pt3Ni / C catalyst of Example 1 of the present invention.

[0022] Figure 3 This is a cyclic voltammetry curve of the core-shell structure Pt3Ni / C catalyst of Example 1 of the present invention.

[0023] Figure 4 This is a linear voltammetric scan of the core-shell structure Pt3Ni / C catalyst of Example 1 of the present invention. Detailed Implementation

[0024] The present invention will be described in detail below with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0025] Example 1

[0026] The preparation process of the 0.5g 50wt% core-shell structured Pt3Ni catalyst in this embodiment is as follows:

[0027] First, add 113.1 mg of nickel nitrate hexahydrate and 0.05 mg of palladium nitrate dihydrate (39 wt% Pd) to 70 ml of pure water and stir until completely dissolved. Next, add 250 mg of EC600JD to the above mixed solution and soak for 8 hours to obtain a mixed solution. Add 40 g / L sodium hydroxide dropwise to control the pH of the mixed solution to 10.5. Then, transfer the adjusted solution to a reactor and introduce argon gas into the reactor. When the oxygen concentration volume fraction at the reactor outlet is less than 0.1% as measured by an oxygen concentration tester, stop the argon gas supply, close the outlet, and start heating. When the temperature reaches 160℃, introduce hydrogen gas at a hydrogen partial pressure of 2.5 MPa and perform a hydrogen reduction reaction under pressure for 120 minutes. Then, turn off the hydrogen gas supply. When the temperature drops to 40℃, introduce argon gas to replace the hydrogen gas. After the hydrogen gas is completely replaced, open the reactor, filter the obtained solution, and wash it with pure water until neutral to obtain carbon-supported nickel nanoparticles.

[0028] The aforementioned carbon-supported nickel nanoparticles were transferred to 100 ml of pure water. 2.27 g of a 10% platinum nitrate solution was weighed and mixed thoroughly. 14% ammonia solution was added dropwise to control the pH to 6.5. The mixture was then soaked for 2 hours and ultrasonically stirred for 6 hours. The adjusted solution was transferred to a reactor, and argon gas was introduced. When the oxygen concentration at the reactor outlet was below 0.1% (measured by an oxygen concentration meter), the argon gas supply was stopped, the outlet was closed, and the temperature was raised. When the temperature reached 90°C, hydrogen gas was introduced at a partial pressure of 0.5 MPa. After a second pressurized hydrogen reduction reaction for 60 minutes, the hydrogen gas supply was stopped. When the temperature dropped to 40°C, argon gas was introduced to replace the hydrogen. After complete hydrogen replacement, the reactor was opened, and the resulting solution was filtered, washed with ethanol, and vacuum dried to obtain 0.4986 g of a core-shell structured Pt3Ni catalyst.

[0029] Depend on Figure 2 It can be seen that the platinum and nickel in the Pt3Ni catalyst of this embodiment form a core-shell structure.

[0030] The core-shell structured Pt3Ni catalyst prepared in this embodiment was subjected to redox testing using a three-electrode system: a hydrogen electrode as the reference electrode, a platinum wire as the counter electrode, a 0.1 M HClO4 solution as the electrolyte, and a scan rate of 10 mV·s. -1The rotation speed was 1600 rpm. The measured electrochemical active area (ECSA) was 63.6 m². 2 ·g -1 The mass activity is 0.72 A·mg. Pt -1 .

[0031] Example 2

[0032] The preparation process of the 1g 20wt% core-shell structured PtNi catalyst in this embodiment is as follows:

[0033] Add 207.2 mg of nickel sulfate hexahydrate and 0.11 mg of palladium nitrate dihydrate (39 wt% Pd) to 50 ml of pure water and stir until completely dissolved. Add 800 mg of BP-2000 to the above mixed solution and soak for 10 hours to obtain a mixed solution. Add 40 g / L sodium hydroxide dropwise to control the pH of the mixed solution to 11. Transfer the adjusted solution to a reactor and introduce nitrogen gas into the reactor. When the oxygen concentration volume fraction at the reactor outlet is lower than 0.1% as measured by an oxygen concentration tester, stop the nitrogen gas supply, close the gas outlet, and start heating. When the temperature reaches 150℃, introduce hydrogen gas at a hydrogen partial pressure of 2.8 MPa and perform a single pressurized hydrogen reduction reaction for 120 minutes. Turn off the hydrogen gas supply and cool down to below 50℃. Then introduce nitrogen gas to replace the hydrogen gas. After the hydrogen gas has been completely replaced, open the reactor, filter the resulting solution, and wash with pure water until neutral to obtain carbon-supported nickel nanoparticles.

[0034] The aforementioned carbon-supported nickel nanoparticles were transferred to 150 ml of pure water. 1.53 g of a 10% platinum nitrate solution was weighed and mixed thoroughly. 14% ammonia was added dropwise to control the pH of the solution to 7. The mixture was stirred and soaked for 4 hours, followed by ultrasonic stirring for 5 hours. The adjusted solution was then transferred to a reactor. Nitrogen gas was introduced into the reactor. When the oxygen concentration at the reactor outlet was lower than 0.1% by an oxygen concentration tester, the nitrogen supply was stopped, the outlet was closed, and the temperature was raised. When the temperature reached 90°C, hydrogen gas was introduced at a partial pressure of 0.3 MPa. After a second pressurized hydrogen reduction reaction for 90 minutes, the hydrogen supply was stopped. When the temperature dropped below 50°C, nitrogen gas was introduced to replace the hydrogen gas. After complete hydrogen replacement, the reactor was opened, and the resulting solution was filtered, washed with ethanol, and vacuum dried to obtain 0.9923 g of a core-shell structured PtNi catalyst.

[0035] The electrochemically active surface area (ECSA) of the PtNi catalyst in Example 2 was measured to be 75.5 m² using the same method as in Example 1. 2 ·g -1 The mass activity is 0.86 A·mg. Pt -1 .

[0036] Example 3

[0037] The preparation process of the 0.5g 40wt% core-shell structured Pt2Ni catalyst in this embodiment is as follows:

[0038] First, add 129.3 mg of nickel nitrate hexahydrate and 0.06 mg of palladium nitrate dihydrate (39 wt% Pd) to 80 ml of pure water and stir until completely dissolved. Next, add 300 mg of EC300JD to the above mixed solution and impregnate and stir for 11 hours to obtain a mixed solution. Add 40 g / L sodium hydroxide dropwise to control the pH of the mixed solution to 9.5. Then, transfer the adjusted solution to a reactor and introduce argon gas into the reactor. When the oxygen concentration volume fraction at the reactor outlet is less than 0.1% as measured by an oxygen concentration tester, stop the argon gas supply, close the outlet, and start heating. When the temperature reaches 140℃, introduce hydrogen gas at a hydrogen partial pressure of 2.2 MPa and perform a hydrogen reduction reaction under pressure for 100 minutes. Then, turn off the hydrogen gas supply. When the temperature drops to 40℃, introduce argon gas to replace the hydrogen gas. After the hydrogen gas is completely replaced, open the reactor, filter the obtained solution, and wash it with pure water until neutral to obtain carbon-supported nickel nanoparticles.

[0039] The aforementioned carbon-supported nickel nanoparticles were transferred to 120 ml of pure water. 1.73 g of a 10% platinum nitrate solution was weighed and mixed thoroughly. 14% ammonia solution was added dropwise to control the pH of the solution to 7. The mixture was then soaked for 3 hours and ultrasonically stirred for 5 hours. The adjusted solution was transferred to a reactor, and argon gas was introduced into the reactor. When the oxygen concentration at the reactor outlet was below 0.1% (measured by an oxygen concentration meter), the argon gas supply was stopped, the outlet was closed, and the temperature was raised. When the temperature reached 70°C, hydrogen gas was introduced at a partial pressure of 0.5 MPa. After a second pressurized hydrogen reduction reaction for 60 minutes, the hydrogen gas supply was stopped. When the temperature dropped to 40°C, argon gas was introduced to replace the hydrogen. After complete hydrogen replacement, the reactor was opened, and the resulting solution was filtered, washed with ethanol, and vacuum dried to obtain 0.4981 g of a core-shell structured Pt₂Ni catalyst.

[0040] The core-shell structured Pt₂Ni catalyst prepared in this embodiment was subjected to redox testing using a three-electrode system: a hydrogen electrode as the reference electrode, a platinum wire as the counter electrode, a 0.1 M HClO₄ solution as the electrolyte, and a scan rate of 10 mV·s. -1 The rotation speed was 1600 rpm. The measured electrochemical active area (ECSA) was 68.2 m². 2 ·g -1 The mass activity is 0.75 A·mg. Pt -1 .

[0041] Comparative Example 1

[0042] Example 1 was repeated, except that palladium nitrate dihydrate was not added. The resulting core-shell Pt3Ni catalyst had an electrochemical active area of ​​30.23 m². 2 ·g -1 The mass activity is 0.22 A·mg. Pt -1 .

[0043] Comparative Example 2

[0044] Example 3 was repeated, except that ultrasonic stirring was omitted. The resulting core-shell PtNi catalyst had an electrochemical active area of ​​40.88 m². 2 ·g -1 The mass activity is 0.48 A·mg. Pt -1 .

[0045] Comparative Example 3

[0046] Example 1 was repeated, except that the pH was adjusted to 8.0 with sodium hydroxide. The resulting core-shell Pt3Ni catalyst had an electrochemical active area of ​​46.78 m². 2 ·g -1 The mass activity is 0.28 A·mg. Pt -1 .

[0047] Comparative Example 4

[0048] Example 1 was repeated, except that the pH was adjusted to 12.5 with sodium hydroxide. The resulting core-shell Pt3Ni catalyst had an electrochemically active surface area of ​​45.23 m². 2 ·g -1 The mass activity is 0.32 A·mg. Pt -1 .

[0049] Comparative Example 5

[0050] Example 2 was repeated, except that the amount of palladium nitrate dihydrate (39 wt% Pd) added was 0.01 mg. The resulting core-shell Pt3Ni catalyst had an electrochemical active surface area of ​​56.7 m². 2 ·g -1 The mass activity is 0.52 A·mg. Pt -1 .

[0051] Comparative Example 6

[0052] Example 2 was repeated, except that the amount of palladium nitrate dihydrate (39 wt% Pd) added was 0.2 mg. The resulting core-shell Pt3Ni catalyst had an electrochemical active area of ​​67.54 m². 2 ·g -1 The mass activity is 0.63 A·mg.Pt -1 .

[0053] Comparative Example 7

[0054] Example 1 was repeated, except that the hydrogen partial pressure was increased to 1.2 MPa in a single pressurization. The resulting core-shell Pt3Ni catalyst had an electrochemically active area of ​​50.32 m². 2 ·g -1 The mass activity is 0.25 A·mg. Pt -1 .

[0055] Comparative Example 8

[0056] Example 1 was repeated, except that the hydrogen partial pressure was increased to 3.2 MPa initially. The resulting core-shell Pt3Ni catalyst had an electrochemically active area of ​​54.22 m². 2 ·g -1 The mass activity is 0.57 A·mg. Pt -1 .

[0057] Comparative Example 9

[0058] Example 1 was repeated, except that the hydrogen reduction temperature under pressure was 110°C. The resulting core-shell Pt3Ni catalyst had an electrochemical active area of ​​48.75 m². 2 ·g -1 The mass activity is 0.47 A·mg. Pt -1 .

[0059] Comparative Example 10

[0060] Example 1 was repeated, except that the hydrogen reduction temperature under pressure was 190°C. The resulting core-shell Pt3Ni catalyst had an electrochemical active area of ​​56.72 m². 2 ·g -1 The mass activity is 0.62 A·mg. Pt -1 .

[0061] Comparative Example 11

[0062] Example 1 was repeated, except that the hydrogen reduction time under pressure was 50 min. The resulting core-shell Pt3Ni catalyst had an electrochemical active area of ​​53.65 m². 2 ·g -1 The mass activity is 0.51 A·mg. Pt -1 .

[0063] Comparative Example 12

[0064] Example 1 was repeated, except that the hydrogen reduction time under pressure was 130 min. The resulting core-shell Pt3Ni catalyst had an electrochemical active area of ​​58.85 m². 2 ·g -1 The mass activity is 0.64 A·mg. Pt -1 .

[0065] Comparative Example 13

[0066] Example 1 was repeated, except that the pH was adjusted to 4.5 with ammonia. The resulting core-shell Pt3Ni catalyst had an electrochemical active area of ​​53.35 m². 2 ·g -1 The mass activity is 0.43 A·mg. Pt -1 .

[0067] Comparative Example 14

[0068] Example 1 was repeated, except that the pH was adjusted to 10 with ammonia. The resulting core-shell Pt3Ni catalyst had an electrochemically active area of ​​52.85 m². 2 ·g -1 The mass activity is 0.39 A·mg. Pt -1 .

[0069] Comparative Example 15

[0070] Example 1 was repeated, except that the hydrogen partial pressure during the secondary pressurization hydrogen reduction was 0.2 MPa. The resulting core-shell Pt3Ni catalyst had an electrochemical active area of ​​54.55 m². 2 ·g -1 The mass activity is 0.53 A·mg. Pt -1 .

[0071] Comparative Example 16

[0072] Example 1 was repeated, except that the hydrogen partial pressure during secondary pressurization was 1.0 MPa. The resulting core-shell Pt3Ni catalyst had an electrochemical active area of ​​49.23 m². 2 ·g -1 The mass activity is 0.48 A·mg. Pt -1 .

[0073] The above embodiments should be understood as being used only to illustrate the present invention more clearly, and not to limit the scope of the present invention. After reading this invention, any modifications of the present invention by those skilled in the art in various equivalent forms fall within the scope defined by the appended claims.

Claims

1. A method for preparing a carbon-supported core-shell structured platinum-nickel catalyst for proton exchange membrane fuel cells, characterized in that: A. Preparation of carbon-supported nickel nanoparticles The nickel salt and palladium nitrate are completely dissolved in pure water, and then the carbon support is added to the solution to obtain a mixed solution. The mixed solution is then stirred and impregnated for 6-12 hours, and then the pH of the solution is adjusted to 9.0-11.5 using sodium hydroxide to obtain a nickel-containing precursor solution. The nickel concentration in the nickel-containing precursor solution is 0.1-2 g / L, the amount of palladium nitrate added is 0.03%-0.16% of the mass of nickel in the nickel-containing precursor solution, and the mass ratio of nickel to carbon support in the mixed solution is 1:4-100. The nickel-containing precursor solution was transferred to a reactor, and a protective gas was introduced. When the volume fraction of oxygen at the reactor outlet was less than 0.1%, the outlet was closed, and the temperature was increased. When the temperature reached 120-180°C, hydrogen gas was introduced at a partial pressure of 1.5-3 MPa. The reaction was carried out for 60-120 minutes. When the temperature was lowered to below 50°C, a protective gas was introduced to replace the hydrogen gas. After the hydrogen gas was completely replaced, the reactor was opened, and the resulting solution was filtered and washed with pure water until neutral to obtain carbon-supported nickel nanoparticles. B. Platinum-loaded Carbon-supported nickel nanoparticles and platinum nitrate were mixed to obtain a mixed slurry. Ammonia water was added dropwise to control the pH of the mixed slurry to 5.0-8.

0. After a second stirring and impregnation for 2-4 hours, ultrasonic stirring was continued for 2-6 hours to obtain a platinum-containing precursor solution. In the mixed slurry, the molar ratio of platinum to nickel was 3-1:1, and the concentration of platinum in the mixed slurry was 0.30-10 g / L. The platinum-containing precursor solution was transferred to a reactor, and a protective gas was introduced into the reactor. When the volume fraction of oxygen at the reactor outlet was less than 0.1%, the outlet was closed, and the temperature was raised. When the temperature reached 40–90°C, hydrogen gas was introduced at a partial pressure of 0.3–0.8 MPa, and the reaction was carried out for 30–90 minutes. Then, when the temperature was lowered to below 50°C, a protective gas was introduced to replace the hydrogen gas. After the hydrogen gas was completely replaced, the reactor was opened, and the resulting solution was filtered, washed with ethanol, and dried under vacuum to obtain a core-shell structured platinum-nickel catalyst.

2. The method for preparing a carbon-supported core-shell structured platinum-nickel catalyst for a proton exchange membrane fuel cell as described in claim 1, characterized in that: The nickel salt is an analytical grade reagent of nickel nitrate hexahydrate or nickel sulfate hexahydrate.

3. The method for preparing a carbon-supported core-shell structured platinum-nickel catalyst for a proton exchange membrane fuel cell as described in claim 1, characterized in that: The palladium nitrate mentioned is analytical grade palladium nitrate dihydrate with a palladium content ≥39wt%.

4. The method for preparing a carbon-supported core-shell structured platinum-nickel catalyst for a proton exchange membrane fuel cell as described in claim 1, characterized in that: The carbon carrier is EC300J, EC600JD or BP-2000.

5. The method for preparing a carbon-supported core-shell structured platinum-nickel catalyst for a proton exchange membrane fuel cell as described in claim 1, characterized in that: The ammonia solution is an analytical grade reagent of 25% to 28%; the sodium hydroxide is an analytical grade reagent; and the platinum nitrate is a platinum nitrate solution with a platinum mass concentration of 10%.

6. The method for preparing a carbon-supported core-shell structured platinum-nickel catalyst for a proton exchange membrane fuel cell as described in claim 1, characterized in that: The hydrogen gas has a purity of not less than 99.99%; the protective gas is nitrogen or argon with a purity of not less than 99.99%.

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