Preparation method and application of proton exchange membrane fuel cell catalyst

Abstract

The invention discloses a preparation method of a proton exchange membrane fuel cell catalyst, the catalyst comprises a carbon black carrier and metal platinum loaded on the carrier, and the mass percentage of platinum in the catalyst is 50%-70%; the preparation method comprises the following steps: 1, uniformly mixing and stirring a carbon black carrier and a metal salt solution to prepare a catalyst carrier for the proton exchange membrane fuel cell; 2, pulping a catalyst carrier with pure water, dropwise adding a chloroplatinic acid solution into the carbon paste under a stirring condition, stirring to be stable, adding an alkali solution, refluxing after stabilization, and cooling to adjust the pH value of the system to be stable; and 3, adding the aqueous solution of the reducing agent into the catalyst, continuously stirring, filtering, washing and drying to obtain the catalyst for the proton exchange membrane fuel cell. The Pt nano-particles of the catalyst prepared by the invention are uniformly dispersed on the surface of the carrier, have uniform particle size, have strong binding force with the carrier, and have high catalyst activity and excellent durability.

Description

Technical Field

[0001] This invention belongs to the field of proton exchange membrane fuel cell technology, specifically relating to a method for preparing a proton exchange membrane fuel cell catalyst and its application. Background Technology

[0002] Fuel cells are a clean energy technology that converts chemical energy into electrical energy. They have advantages such as high energy conversion efficiency, low operating temperature, fast start-up and high energy density. They can be widely used in aviation, aerospace, marine, rail transportation, electronic equipment and backup power, and have important application value, especially in the field of new energy vehicles.

[0003] As a core material in hydrogen fuel cells, the comprehensive performance and domestic production of catalysts directly affect the core competitiveness and industrialization prospects of my country's hydrogen energy industry. However, due to the complex operating conditions of the battery, the carbon support of the platinum-based cathode catalyst is prone to corrosion, precious metal particles are easily detached, and Ostwald aging and agglomeration occur, affecting the catalyst's lifespan. This research focuses on low-cost, highly graphitized supports to improve their resistance to electrochemical corrosion under acidic, high-potential, oxygen-rich conditions, effectively addressing the stability of carbon support materials and thus improving catalyst stability. Simultaneously, it investigates heteroatom doping and platinum loading methods on the support, utilizing the directional coordination between lone pair electrons on the support surface and the d orbitals of Pt atoms to achieve efficient anchoring of Pt on the support surface, enhancing the metal-support interaction and improving activity and durability.

[0004] Chinese patent application No. 202111243337.1, published on October 25, 2021, discloses a method for graphitizing carbon black. However, this method suffers from problems such as excessively high graphitization temperature (2300℃), resulting in high energy consumption and significant damage to the structure of the carbon support itself. Chinese patent application No. 202411255252.9, published on October 11, 2024, discloses a method for preparing a platinum-based catalyst supported on a porous graphitized carbon support. The platinum-based catalyst supported on the porous graphitized carbon support prepared by this invention can effectively improve the catalytic activity and stability of the catalyst material. However, this invention mainly uses polymer materials as carbon precursors, resulting in low porous carbon yield and difficulty in industrial scale-up. Summary of the Invention

[0005] The technical problem this invention aims to solve is to address the shortcomings of the prior art by providing a method for preparing a proton exchange membrane fuel cell catalyst and its application. This method involves first preparing [Pt(OH)6]. 2-The Pt nanoparticles are uniformly adsorbed on the surface of the carbon black support. Then, the pH of the system is adjusted by phosphoric acid to generate H2Pt(OH)6. A reducing agent is added in the presence of a phosphate buffer to prepare a catalyst. The Pt nanoparticles are uniformly dispersed on the support surface and have a uniform particle size. They have a strong binding force with the support, and the catalyst has high activity and good durability.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing a proton exchange membrane fuel cell catalyst, characterized in that the catalyst includes a carbon black support and metallic platinum supported on the support, wherein the mass percentage of platinum in the catalyst is 50% to 70%.

[0007] The preparation method includes the following steps:

[0008] Step 1: Mix the carbon black support with the metal salt solution and stir evenly. Add a reducing agent for reduction, filter, wash, dry and place in a tube furnace. Maintain at 600℃~1000℃ for 2h~4h under an ammonia atmosphere. After cooling, ultrasonically disperse in an acid solution and reflux at 50℃~90℃ for 3h~5h. Wash with water until the pH of the filtrate is neutral and dry to obtain the catalyst support for proton exchange membrane fuel cells.

[0009] Step 2: Slurry the catalyst support prepared in Step 1 with pure water. Under stirring conditions, add chloroplatinic acid solution dropwise to the slurry and stir to stabilize for 30 min. Add alkaline solution and stabilize for 30 min. Reflux at 100℃ for 10 h to 15 h. After cooling, add phosphoric acid solution to adjust the pH of the system and stabilize for another 4 h to 6 h.

[0010] Step 3: Add the aqueous solution of the reducing agent to the system after adjusting and stabilizing the pH value in Step 2, continue stirring for 3 to 4 hours, filter, wash, and dry to obtain the catalyst for proton exchange membrane fuel cells.

[0011] The above-mentioned method for preparing a proton exchange membrane fuel cell catalyst is characterized in that the carbon black support in step one is at least one of EC600JD, EC300J, XC-72R, BP2000 and XE-2B.

[0012] The above-mentioned method for preparing a proton exchange membrane fuel cell catalyst is characterized in that the metal in the metal salt solution in step one is iron, cobalt or nickel, the metal salt solution is a nitrate, sulfate or chloride of the metal, and the mass of the metal is 1 / 10 to 1 / 30 of the mass of carbon black.

[0013] The above-mentioned method for preparing a proton exchange membrane fuel cell catalyst is characterized in that the reducing agent in step one is at least one of sodium borohydride, potassium borohydride and hydrazine hydrate, and the mass of the reducing agent is 5 to 10 times the mass of the metal substance.

[0014] The method for preparing a proton exchange membrane fuel cell catalyst described above is characterized in that the acid solution in step one is a 0.5 mol / L to 3 mol / L sulfuric acid solution or a 0.5 mol / L to 3 mol / L nitric acid solution.

[0015] The above-mentioned method for preparing a proton exchange membrane fuel cell catalyst is characterized in that the alkaline solution in step two is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate, and the amount of the alkaline is 10 to 40 times the amount of platinum metal.

[0016] The method for preparing a proton exchange membrane fuel cell catalyst described above is characterized in that the pH range of the phosphoric acid adjustment system in step two is 4 to 6.

[0017] The above-mentioned method for preparing a proton exchange membrane fuel cell catalyst is characterized in that the reducing agent in step three is at least one of sodium borohydride, potassium borohydride, formic acid, sodium formate, and formaldehyde, and the mass of the reducing agent is 5 to 10 times the mass of platinum.

[0018] Furthermore, the present invention also provides an application of the catalyst obtained by the above preparation method in a proton exchange membrane fuel cell.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. This invention uses common commercial carbon black as the matrix, which has high yield, low cost, and is easy to industrialize.

[0021] 2. In this invention, carbon black support is mixed and stirred evenly with metal salt solution, and a reducing agent is added for reduction. The reduced metal is uniformly doped into the support, which lowers the graphitization temperature of the support. This allows the support to achieve a high degree of graphitization at a lower temperature, avoiding the collapse of the support pore structure at high temperatures (around 1500℃), which would lead to a sharp decrease in specific surface area and affect catalyst performance.

[0022] 3. This invention improves the activity of the catalyst by treating the support with ammonia.

[0023] 4. In the preparation method of the present invention, [Pt(OH)6] is prepared first. 2- The Pt nanoparticles are uniformly adsorbed on the surface of the carbon black support. Then, the pH of the system is adjusted by phosphoric acid to generate H2Pt(OH)6. A reducing agent is added in the presence of a phosphate buffer to prepare a catalyst. The Pt nanoparticles are uniformly dispersed on the support surface and have a uniform particle size. They have a strong binding force with the support, and the catalyst has high activity and good durability.

[0024] The technical solution of the present invention will be further described in detail below with reference to the embodiments. Detailed Implementation

[0025] The present invention will be further described below with reference to specific embodiments in order to more clearly explain the advantages of the present invention. The embodiments described are merely exemplary and do not constitute any limitation on the scope of the present invention.

[0026] Example 1

[0027] This embodiment of a catalyst for a proton exchange membrane fuel cell includes a carbon black support and a metal component supported on the carbon black support. The metal component is Pt, and the mass percentage of platinum in the catalyst is 50%.

[0028] The preparation method of a catalyst for a proton exchange membrane fuel cell according to this embodiment includes the following steps:

[0029] Step 1: Weigh 3.607g of Fe(NO3)3·9H2O and dissolve it in 400mL of water. Add 5g of carbon black EC600JD and stir well. Weigh 2.5g of sodium borohydride and dissolve it in 100mL of water. Then add it dropwise to the carbon slurry for 30min. Stabilize for 30min. Filter, wash and dry. Keep the dried carbon black at 800℃ for 3h in a tube furnace under an ammonia atmosphere. After cooling, ultrasonically disperse it in 400mL of 0.5M nitric acid solution. Reflux at 80℃ for 3h. Wash with water until the pH of the filtrate is neutral. Dry at 100℃ to obtain the catalyst support for proton exchange membrane fuel cells.

[0030] Step 2: Weigh 2.5g of the carrier prepared in Step 1 and slurry it with 200mL of pure water. Under stirring conditions, add 2.5g of chloroplatinic acid solution containing platinum dropwise to the slurry and stir to stabilize for 30min. Add an aqueous solution containing 10.252g of sodium hydroxide and stabilize for 30min. Reflux at 100℃ for 12h. After cooling, add phosphoric acid solution to adjust the pH of the system to 4.5 and stabilize for 4h.

[0031] Step 3: Add 100 mL of an aqueous solution containing 12.5 g of sodium borohydride to the catalyst from Step 2, continue stirring for 3 h, filter, wash and dry to obtain the catalyst for proton exchange membrane fuel cells.

[0032] Example 2

[0033] This embodiment of a catalyst for a proton exchange membrane fuel cell includes a carbon black support and a metal component supported on the carbon black support. The metal component is Pt, and the mass percentage of platinum in the catalyst is 70%.

[0034] The preparation method of a catalyst for a proton exchange membrane fuel cell according to this embodiment includes the following steps:

[0035] Step 1: Weigh 0.673g of CoCl2·6H2O and dissolve it in 400mL of water. Add 5g of carbon black EC300J and stir well. Weigh 1.667g of potassium borohydride and dissolve it in 100mL of water. Add the solution dropwise to the carbon slurry for 30 minutes. Stabilize for 30 minutes. Filter, wash, and dry. Keep the dried carbon black at 600℃ for 4 hours in a tube furnace under an ammonia atmosphere. After cooling, ultrasonically disperse it in 400mL of 3M sulfuric acid solution. Reflux at 90℃ for 3 hours. Wash with water until the pH of the filtrate is neutral. Dry at 100℃ to obtain the catalyst support for proton exchange membrane fuel cells.

[0036] Step 2: Weigh 1.5g of the carrier prepared in Step 1 and slurry it with 200mL of pure water. Under stirring conditions, add 3.5g of chloroplatinic acid solution containing platinum dropwise to the carbon slurry and stir to stabilize for 30min. Add an aqueous solution containing 10.046g of potassium hydroxide and stabilize for 30min. Reflux at 100℃ for 15h. After cooling, add phosphoric acid solution to adjust the pH of the system to 4 and stabilize for 6h.

[0037] Step 3: Add 100 mL of an aqueous solution containing 21 g of potassium borohydride to the catalyst from Step 2, continue stirring for 4 h, filter, wash and dry to obtain the catalyst for proton exchange membrane fuel cells.

[0038] Example 3

[0039] This embodiment of a catalyst for a proton exchange membrane fuel cell includes a carbon black support and a metal component supported on the carbon black support. The metal component is Pt, and the mass percentage of platinum in the catalyst is 60%.

[0040] The preparation method of a catalyst for a proton exchange membrane fuel cell according to this embodiment includes the following steps:

[0041] Step 1: Weigh 1.2388g of Ni(NO3)2·6H2O and dissolve it in 400mL of water. Add 5g of carbon black BP-2000 and stir well. Measure 2mL of hydrazine hydrate and dissolve it in 100mL of water. Add it dropwise to the carbon slurry for 30min and stabilize for 30min. Filter, wash, and dry. Keep the dried carbon black at 1000℃ for 2h in a tube furnace under an ammonia atmosphere. After cooling, ultrasonically disperse it in 400mL of 2M nitric acid solution and reflux at 50℃ for 5h. Wash with water until the pH of the filtrate is neutral and dry at 100℃ to obtain the catalyst support for proton exchange membrane fuel cells.

[0042] Step 2: Weigh 2.0g of the carrier prepared in Step 1 and slurry it with 200mL of pure water. Under stirring conditions, add 3.0g of chloroplatinic acid solution containing platinum dropwise to the carbon slurry and stir to stabilize for 30min. Add an aqueous solution containing 51.670g of sodium bicarbonate and stabilize for 30min. Reflux at 100℃ for 10h. After cooling, add phosphoric acid solution to adjust the pH of the system to 6 and stabilize for 5h.

[0043] Step 3: Add 100 mL of an aqueous solution containing 30 mL of formaldehyde to the catalyst from Step 2, continue stirring for 3 hours, filter, wash and dry to obtain the catalyst for proton exchange membrane fuel cells.

[0044] Example 4

[0045] This embodiment of a catalyst for a proton exchange membrane fuel cell includes a carbon black support and a metal component supported on the carbon black support. The metal component is Pt, and the mass percentage of platinum in the catalyst is 55%.

[0046] The preparation method of a catalyst for a proton exchange membrane fuel cell according to this embodiment includes the following steps:

[0047] Step 1: Weigh 3.3467g of Fe2(SO4)3·9H2O and dissolve it in 400mL of water. Add 5g of carbon black XC-72R and stir evenly. Weigh 2.4975g of sodium borohydride and dissolve it in 100mL of water. Add the solution dropwise to the carbon slurry for 30min. Stabilize for 30min. Filter, wash, and dry. Keep the dried carbon black at 700℃ for 3h in a tube furnace under an ammonia atmosphere. After cooling, ultrasonically disperse it in 400mL of 1M sulfuric acid solution. Reflux at 70℃ for 4h. Wash with water until the pH of the filtrate is neutral. Dry at 100℃ to obtain the catalyst support for proton exchange membrane fuel cells.

[0048] Step 2: Weigh 2.25g of the carrier prepared in Step 1 and slurry it with 200mL of pure water. Under stirring conditions, add 2.75g of chloroplatinic acid solution containing platinum dropwise to the carbon slurry and stir to stabilize for 30min. Add an aqueous solution containing 41.4437g of sodium carbonate and stabilize for 30min. Reflux at 100℃ for 13h. After cooling, add phosphoric acid solution to adjust the pH of the system to 5 and stabilize for 4h.

[0049] Step 3: Add 100 mL of an aqueous solution containing 22 g of sodium formate to the catalyst from Step 2, continue stirring for 3 h, filter, wash and dry to obtain the catalyst for proton exchange membrane fuel cells.

[0050] Example 5

[0051] This embodiment of a catalyst for a proton exchange membrane fuel cell includes a carbon black support and a metal component supported on the carbon black support. The metal component is Pt, and the mass percentage of platinum in the catalyst is 50%.

[0052] The preparation method of a catalyst for a proton exchange membrane fuel cell according to this embodiment includes the following steps:

[0053] Step 1: Weigh 0.9652g of FeCl3·6H2O and dissolve it in 400mL of water. Add 5g of carbon black XE-2B and stir well. Measure 1.2g of potassium borohydride and dissolve it in 100mL of water. Add the solution dropwise to the carbon slurry for 30min. Stabilize for 30min. Filter, wash, and dry. Keep the dried carbon black at 900℃ for 3h in a tube furnace under an ammonia atmosphere. After cooling, ultrasonically disperse it in 400mL of 1M nitric acid solution. Reflux at 60℃ for 5h. Wash with water until the pH of the filtrate is neutral. Dry at 100℃ to obtain the catalyst support for proton exchange membrane fuel cells.

[0054] Step 2: Weigh 2.5g of the carrier prepared in Step 1 and slurry it with 200mL of pure water. Under stirring conditions, add 2.5g of chloroplatinic acid solution containing platinum dropwise to the carbon slurry and stir to stabilize for 30min. Add an aqueous solution containing 26.5666g of potassium carbonate and stabilize for 30min. Reflux at 100℃ for 11h. After cooling, add phosphoric acid solution to adjust the pH of the system to 5.5 and stabilize for 6h.

[0055] Step 3: Add 100 mL of an aqueous solution containing 25 mL of formic acid to the catalyst from Step 2, continue stirring for 3 hours, filter, wash and dry to obtain the catalyst for proton exchange membrane fuel cells.

[0056] Example 6

[0057] This embodiment of a catalyst for a proton exchange membrane fuel cell includes a carbon black support and a metal component supported on the carbon black support. The metal component is Pt, and the mass percentage of platinum in the catalyst is 50%.

[0058] The preparation method of a catalyst for a proton exchange membrane fuel cell according to this embodiment includes the following steps:

[0059] Step 1: Weigh 3.607g of Fe(NO3)3·9H2O and dissolve it in 400mL of water. Add 5g of carbon black EC600JD and stir evenly. Weigh 2.5g of sodium borohydride and dissolve it in 100mL of water. Add the solution dropwise to the carbon slurry for 30min. Stabilize for 30min. Filter, wash, and dry. Keep the dried carbon black at 800℃ for 3h in a tube furnace under an ammonia atmosphere. After cooling, ultrasonically disperse it in 400mL of 0.5M nitric acid solution. Reflux at 80℃ for 3h. Wash with water until the pH of the filtrate is neutral. Dry at 100℃ to obtain the catalyst support for proton exchange membrane fuel cells.

[0060] Step 2: Weigh 2.5g of the carrier prepared in Step 1 and slurry it with 200mL of pure water. Under stirring conditions, add 2.5g of chloroplatinic acid solution containing platinum dropwise to the carbon slurry and stir to stabilize for 30min. Add an aqueous solution containing 44.9058g of potassium bicarbonate and stabilize for 30min. Reflux at 100℃ for 12h. After cooling, add phosphoric acid solution to adjust the pH of the system to 4.5 and stabilize for 4h.

[0061] Step 3: Add 100 mL of an aqueous solution containing 12.5 g of sodium borohydride to the catalyst from Step 2, continue stirring for 3 h, filter, wash and dry to obtain the catalyst for proton exchange membrane fuel cells.

[0062] Comparative Example 1

[0063] Unlike Example 1, in step one, Fe(NO3)3·9H2O was not reduced and was directly mixed with carbon black and dried.

[0064] This comparative example provides a catalyst for a proton exchange membrane fuel cell, comprising a carbon black support and a metal component supported on the carbon black support, wherein the metal component is Pt, and the catalyst contains 50% platinum by mass.

[0065] The preparation method of a catalyst for a proton exchange membrane fuel cell in this comparative example includes the following steps:

[0066] Step 1: Weigh 3.607g of Fe(NO3)3·9H2O and dissolve it in 400mL of water. Add 5g of carbon black EC600JD, stir evenly and dry. Keep the dried carbon black at 800℃ for 3h in a tube furnace under an ammonia atmosphere to obtain a catalyst support for proton exchange membrane fuel cells.

[0067] Step 2: Weigh 2.5g of the carrier prepared in Step 1 and slurry it with 200mL of pure water. Under stirring conditions, add 2.5g of chloroplatinic acid solution containing platinum dropwise to the carbon slurry and stir to stabilize for 30min. Add an aqueous solution containing 10.252g of sodium hydroxide and stabilize for 30min. Reflux at 100℃ for 12h. After cooling, add phosphoric acid solution to adjust the pH of the system to 4.5 and stabilize for 4h.

[0068] Step 3: Add 100 mL of an aqueous solution containing 12.5 g of sodium borohydride to the catalyst from Step 2, continue stirring for 3 h, filter, wash and dry to obtain the catalyst for proton exchange membrane fuel cells.

[0069] Comparative Example 2

[0070] Unlike Example 1, the gas atmosphere processed in the carrier tube furnace in step one is nitrogen.

[0071] This comparative example provides a catalyst for a proton exchange membrane fuel cell, comprising a carbon black support and a metal component supported on the carbon black support, wherein the metal component is Pt, and the catalyst contains 50% platinum by mass.

[0072] The preparation method of a catalyst for a proton exchange membrane fuel cell in this comparative example includes the following steps:

[0073] Step 1: Weigh 3.607g of Fe(NO3)3·9H2O and dissolve it in 400mL of water. Add 5g of carbon black EC600JD and stir evenly. Weigh 2.5g of sodium borohydride and dissolve it in 100mL of water. Add the solution dropwise to the carbon slurry for 30min. Stabilize for 30min. Filter, wash, and dry. Keep the dried carbon black at 800℃ for 3h in a tube furnace under nitrogen atmosphere. After cooling, ultrasonically disperse it in 400mL of 0.5M nitric acid solution. Reflux at 80℃ for 3h. Wash with water until the pH of the filtrate is neutral. Dry at 100℃ to obtain the catalyst support for proton exchange membrane fuel cells.

[0074] Step 2: Weigh 2.5g of the carrier prepared in Step 1 and slurry it with 200mL of pure water. Under stirring conditions, add 2.5g of chloroplatinic acid solution containing platinum dropwise to the carbon slurry and stir to stabilize for 30min. Add an aqueous solution containing 10.252g of sodium hydroxide and stabilize for 30min. Reflux at 100℃ for 12h. After cooling, add phosphoric acid solution to adjust the pH of the system to 4.5 and stabilize for 4h.

[0075] Step 3: Add 100 mL of an aqueous solution containing 12.5 g of sodium borohydride to the catalyst from Step 2, continue stirring for 3 h, filter, wash and dry to obtain the catalyst for proton exchange membrane fuel cells.

[0076] Comparative Example 3

[0077] Unlike Example 1, in step two, the reducing agent is added directly after the platinum active component is added.

[0078] This comparative example provides a catalyst for a proton exchange membrane fuel cell, comprising a carbon black support and a metal component supported on the carbon black support, wherein the metal component is Pt, and the catalyst contains 50% platinum by mass.

[0079] The preparation method of a catalyst for a proton exchange membrane fuel cell in this comparative example includes the following steps:

[0080] Step 1: Weigh 3.607g of Fe(NO3)3·9H2O and dissolve it in 400mL of water. Add 5g of carbon black EC600JD and stir evenly. Weigh 2.5g of sodium borohydride and dissolve it in 100mL of water. Add the solution dropwise to the carbon slurry for 30min. Stabilize for 30min. Filter, wash, and dry. Keep the dried carbon black at 800℃ for 3h in a tube furnace under an ammonia atmosphere. After cooling, ultrasonically disperse it in 400mL of 0.5M nitric acid solution. Reflux at 80℃ for 3h. Wash with water until the pH of the filtrate is neutral. Dry at 100℃ to obtain the catalyst support for proton exchange membrane fuel cells.

[0081] Step 2: Weigh 2.5g of the carrier prepared in Step 1 and slurry it with 200mL of pure water. Under stirring conditions, add 2.5g of chloroplatinic acid solution containing platinum dropwise to the carbon slurry and stir for 30min to stabilize.

[0082] Step 3: Add 100 mL of an aqueous solution containing 12.5 g of sodium borohydride to the catalyst from Step 2, continue stirring for 3 h, filter, wash and dry to obtain the catalyst for proton exchange membrane fuel cells.

[0083] Comparative Example 4

[0084] Unlike Example 1, the nitric acid solution used to adjust the pH in step two is different.

[0085] This comparative example provides a catalyst for a proton exchange membrane fuel cell, comprising a carbon black support and a metal component supported on the carbon black support, wherein the metal component is Pt, and the catalyst contains 50% platinum by mass.

[0086] The preparation method of a catalyst for a proton exchange membrane fuel cell in this comparative example includes the following steps:

[0087] Step 1: Weigh 3.607g of Fe(NO3)3·9H2O and dissolve it in 400mL of water. Add 5g of carbon black EC600JD and stir evenly. Weigh 2.5g of sodium borohydride and dissolve it in 100mL of water. Add the solution dropwise to the carbon slurry for 30min. Stabilize for 30min. Filter, wash, and dry. Keep the dried carbon black at 800℃ for 3h in a tube furnace under an ammonia atmosphere. After cooling, ultrasonically disperse it in 400mL of 0.5M nitric acid solution. Reflux at 80℃ for 3h. Wash with water until the pH of the filtrate is neutral. Dry at 100℃ to obtain the catalyst support for proton exchange membrane fuel cells.

[0088] Step 2: Weigh 2.5g of the carrier prepared in Step 1 and slurry it with 200mL of pure water. Under stirring conditions, add 2.5g of chloroplatinic acid solution containing platinum dropwise to the carbon slurry and stir to stabilize for 30min. Add an aqueous solution containing 10.252g of sodium hydroxide and stabilize for 30min. Reflux at 100℃ for 12h. After cooling, add nitric acid solution to adjust the pH of the system to 4.5 and stabilize for 4h.

[0089] Step 3: Add 100 mL of an aqueous solution containing 12.5 g of sodium borohydride to the catalyst from Step 2, continue stirring for 3 h, filter, wash and dry to obtain the catalyst for proton exchange membrane fuel cells.

[0090] Performance Evaluation

[0091] The catalyst was prepared into a film electrode and assembled into a battery for performance testing.

[0092] Polarization curve testing: Polarization curve testing was conducted using a fuel cell test bench. During the test, air was passed through the cathode and hydrogen was passed through the anode, with a current density of 100 mA·cm⁻¹. -2 Increase from 0 to 2000 mA·cm -2 Test the voltage values ​​corresponding to different current densities.

[0093] Accelerated Catalyst Durability Testing (ADT): Catalyst durability testing was conducted using a fuel cell bench. During the test, nitrogen gas was introduced to the cathode and hydrogen gas to the anode. Step voltages of 0.6V–3s and 0.95V–3s were applied, and the test was cycled for 30K cycles. The electrochemical active area (ECSA) of the membrane electrode assembly was measured before and after the test. After measuring the ECSA, air was introduced to the cathode and hydrogen gas to the anode, and the polarization curve was measured and recorded at 800 mA·cm⁻¹. -2 The voltage value at that location.

[0094] Accelerated Durability Testing (ADT) of Catalyst Support: Catalyst durability testing was conducted using a fuel cell bench. During the test, nitrogen gas was introduced to the cathode and hydrogen gas to the anode. A triangular wave voltage of 1–1.5 V was applied, and the test was cycled 5000 times. The electrochemical active area (ECSA) of the membrane electrode assembly was measured before and after the test. After measuring the ECSA, air was introduced to the cathode and hydrogen gas to the anode, and the polarization curve was measured and recorded at 1500 mA·cm⁻¹. -2 The voltage value at that location.

[0095] The initial and post-durability data of the films-coated electrodes prepared with catalysts from different embodiments are shown in Table 1.

[0096] Table 1 Catalyst durability - voltage (E) and electrochemical active area (ECSA)

[0097]

[0098]

[0099] Table 2 Catalyst support durability - voltage (E) and electrochemical active area (ECSA)

[0100]

[0101] As shown in Tables 1 and 2, after the accelerated catalyst durability test (ADT) of the catalyst prepared by the method of this invention, the membrane electrode exhibits a performance of 0.8 A·cm⁻¹. -2 The decay value is 3–10 mV, and the electrochemical active area (ECSA) decays by 6.24%–13.6%, exhibiting good catalyst activity and durability. After accelerated durability testing (ADT) on the catalyst support, the membrane electrode exhibits good performance at 1.5 A·cm⁻¹. -2 The degradation value was 5–11 mV, and the electrochemical active area (ECSA) degradation was 8.99%–15.44%, indicating good catalyst support durability. In contrast, the catalyst prepared by the comparative method showed lower activity than the catalyst of this invention, and after accelerated catalyst durability testing (ADT), the membrane electrode exhibited poor performance at 0.8 A·cm⁻¹. -2 The decay value was 17–30 mV, and the electrochemical active area (ECSA) decayed by 16.44%–28.8%, indicating moderate catalyst activity and durability. The catalyst prepared using the comparative method, after accelerated durability testing (ADT) on the catalyst support, showed that the membrane electrode at 1.5 A·cm⁻¹... -2 The decay value is 25-50 mV, the electrochemical active area (ECSA) decays by 25.36%-41.22%, and the catalyst support durability is generally average.

[0102] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a proton exchange membrane fuel cell catalyst, characterized in that, The catalyst comprises a carbon black support and metallic platinum supported on the support, wherein the mass percentage of platinum in the catalyst is 50% to 70%. The preparation method includes the following steps: Step 1: Mix the carbon black support with the metal salt solution and stir evenly. Add a reducing agent for reduction, filter, wash, dry and place in a tube furnace. Maintain at 600℃~1000℃ for 2h~4h under an ammonia atmosphere. After cooling, ultrasonically disperse in an acid solution and reflux at 50℃~90℃ for 3h~5h. Wash with water until the pH of the filtrate is neutral and dry to obtain the catalyst support for proton exchange membrane fuel cells. Step 2: Slurry the catalyst support prepared in Step 1 with pure water. Under stirring conditions, add chloroplatinic acid solution dropwise to the slurry and stir to stabilize for 30 min. Add alkaline solution and stabilize for 30 min. Reflux at 100℃ for 10 h to 15 h. After cooling, add phosphoric acid solution to adjust the pH of the system and stabilize for another 4 h to 6 h. Step 3: Add the aqueous solution of the reducing agent to the system after adjusting and stabilizing the pH value in Step 2, continue stirring for 3 to 4 hours, filter, wash, and dry to obtain the catalyst for proton exchange membrane fuel cells.

2. The method for preparing a proton exchange membrane fuel cell catalyst according to claim 1, characterized in that, The carbon black carrier mentioned in step one is at least one of EC600JD, EC300J, XC-72R, BP2000 and XE-2B.

3. The method for preparing a proton exchange membrane fuel cell catalyst according to claim 1, characterized in that, The metal in the metal salt solution mentioned in step one is iron, cobalt, or nickel, and the metal salt solution is a nitrate, sulfate, or chloride of the metal. The mass of the metal is 1 / 10 to 1 / 30 of the mass of the carbon black.

4. The method for preparing a proton exchange membrane fuel cell catalyst according to claim 1, characterized in that, The reducing agent mentioned in step one is at least one of sodium borohydride, potassium borohydride, and hydrazine hydrate, and the mass of the reducing agent is 5 to 10 times the mass of the metal substance.

5. The method for preparing a proton exchange membrane fuel cell catalyst according to claim 1, characterized in that, The acid solution mentioned in step one is a 0.5 mol / L to 3 mol / L sulfuric acid solution or a 0.5 mol / L to 3 mol / L nitric acid solution.

6. The method for preparing a proton exchange membrane fuel cell catalyst according to claim 1, characterized in that, The alkaline solution mentioned in step two is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate, and the amount of the alkali is 10 to 40 times the amount of platinum metal.

7. The method for preparing a proton exchange membrane fuel cell catalyst according to claim 1, characterized in that, The pH range of the phosphoric acid adjustment system described in step two is 4–6.

8. The method for preparing a proton exchange membrane fuel cell catalyst according to claim 1, characterized in that, The reducing agent mentioned in step three is at least one of sodium borohydride, potassium borohydride, formic acid, sodium formate, and formaldehyde, and the mass of the reducing agent is 5 to 10 times the mass of platinum.

9. The application of a catalyst obtained by the preparation method described in claim 1 in a proton exchange membrane fuel cell.

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