A platinum-based hydrogen fuel cell catalyst, its preparation method and application

Abstract

The application belongs to the technical field of fuel cell catalysts, and particularly relates to a platinum-based hydrogen fuel cell catalyst and a preparation method and application thereof. The preparation method is to perform step-by-step gradient temperature oxidation treatment on a carbon carrier in an air atmosphere, then mix the carbon carrier with a platinum salt solution, and then perform step-by-step gradient temperature heating reduction treatment on the mixed reaction liquid under inert gas protection, so as to control the platinum particle size, dispersity and stability, and obtain a platinum-based hydrogen fuel cell catalyst with high activity and good stability. The catalyst exhibits excellent performance on a membrane electrode, and the preparation method has simple synthesis process and low cost.

Description

Technical Field

[0001] This invention relates to the field of fuel cell catalyst technology, specifically to a platinum-based hydrogen fuel cell catalyst, its preparation method, and its application. Background Technology

[0002] Hydrogen fuel cells have become an important choice for new energy vehicles and stationary power generation systems due to their high energy conversion efficiency and environmental friendliness. The catalyst is one of the core components of a hydrogen fuel cell, and its performance directly affects the cell's output power and lifespan. Currently, commercially available catalysts are mainly platinum-carbon (Pt / C) materials.

[0003] In existing technologies, high-platinum-supported catalysts generally suffer from problems such as easy agglomeration of platinum particles, uneven dispersion, and poor stability. Traditional impregnation and chemical reduction methods are difficult to control the size and distribution of platinum particles while ensuring high loading. In addition, carbon supports are prone to corrosion during fuel cell operation, leading to platinum particle detachment and further reducing catalyst durability.

[0004] Therefore, developing a method for preparing platinum-based catalysts that can achieve high platinum loading, high dispersibility, high stability, and is simple and low-cost has important practical application value. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a platinum-based hydrogen fuel cell catalyst, its preparation method, and its application. This method significantly improves the dispersibility and stability of platinum particles while maintaining high electrochemical activity through stepwise gradient oxidation of the carbon support and stepwise gradient reduction of the platinum precursor.

[0006] To achieve the above-mentioned objectives, the present invention first proposes a method for preparing a platinum-based hydrogen fuel cell catalyst, comprising the following steps:

[0007] S1. Carrier pretreatment and dispersion: The carbon carrier is subjected to stepwise gradient heating oxidation treatment in air atmosphere, and then the oxidized carbon carrier is dispersed in ethylene glycol aqueous solution a. After mixing evenly, a uniform carbon carrier dispersion is obtained.

[0008] Preparation of platinum salt solution: Disperse platinum salt in ethylene glycol aqueous solution b, and mix thoroughly to obtain a homogeneous platinum salt solution;

[0009] S2. Mix the carbon support dispersion obtained in step S1 with the platinum salt solution, and adjust the pH value to 8-10 with alkali solution to obtain a uniformly mixed reaction solution.

[0010] S3. The mixed reaction solution is subjected to stepwise gradient heating reduction treatment under inert gas protection;

[0011] S4. The product obtained in step S3 is filtered, washed and vacuum dried to obtain the platinum-based hydrogen fuel cell catalyst.

[0012] More preferably, the carbon carrier is selected from at least one of biomass carbon, Cabot carbon black, mesoporous carbon, and Ketjen black carbon.

[0013] More preferably, the stepwise gradient temperature oxidation treatment in step S1 includes the following steps:

[0014] First stage: Treat at 150-200℃ for 1-2 hours;

[0015] Second stage: Treat at 250-300℃ for 1-2 hours;

[0016] Third stage: Treat at 350-400℃ for 20-40 minutes.

[0017] More preferably, in both the ethylene glycol aqueous solutions a and b, water accounts for 50% of the volume.

[0018] More preferably, the platinum salt is selected from at least one of platinum tetrachloride, chloroplatinic acid, platinum nitrate, and ammonium chloroplatinate.

[0019] More preferably, the uniform mixing in steps S1 and S2 is achieved by mechanical stirring, ultrasonic treatment, or a combination thereof. Specifically, the steps are: stirring for 20 to 30 minutes, then ultrasonicating for 10 to 20 minutes, and repeating until the mixture is uniformly dispersed.

[0020] More preferably, the step-by-step gradient heating and reduction in step S3 includes the following steps:

[0021] First stage: React at 55-65℃ for 1-2 hours;

[0022] Second stage: React at 70-80℃ for 1-2 hours;

[0023] Third stage: Reaction at 85-95℃ for 1-2 hours.

[0024] More preferably, the inert gas in step S3 is nitrogen or argon.

[0025] In addition, the present invention also proposes a platinum-based hydrogen fuel cell catalyst prepared by the above method, wherein the platinum loading in the catalyst is 40-60 wt% and the average particle size of the platinum particles is 2-3 nm.

[0026] In addition, the present invention also proposes an application of the catalyst described above in the membrane electrode of a hydrogen fuel cell.

[0027] Compared with the prior art, the present invention has the following significant advantages:

[0028] 1. High dispersibility: Gradient oxidation carbon support and gradient reduction process significantly improve platinum loading (≥40wt%), while ensuring small platinum nanoparticle size (2-3nm) and uniform distribution, avoiding agglomeration.

[0029] 2. High activity and stability: The optimized carbon support surface oxygen-containing functional groups enhance the platinum anchoring ability, improve the chemical stability and durability of the catalyst, and at the same time maintain activity.

[0030] 3. Simple process, suitable for industrialization: Only conventional stirring, ultrasonic and heating equipment are required. No complex templates or precious metal precursors are needed. The cost is low and it is easy to scale up production. Attached Figure Description

[0031] The above features and advantages of the present invention will become clearer and more readily understood from the following description of exemplary embodiments thereof in conjunction with the accompanying drawings.

[0032] Figure 1 XRD patterns of platinum-based hydrogen fuel cell catalysts prepared in Examples 1, 2, 3 and Comparative Example 2;

[0033] Figure 2 TEM image of the platinum-based hydrogen fuel cell catalyst prepared in Example 2;

[0034] Figure 3 The polarization curves of the platinum-based hydrogen fuel cell catalysts prepared in Example 2 and Comparative Example 2 on the RDE are shown.

[0035] Figure 4 The 25cm sample was prepared from the platinum-based hydrogen fuel cell catalyst obtained in Example 1. 2 Polarization curves of the membrane electrode before and after aging test;

[0036] Figure 5 The 25cm sample prepared for the platinum-based hydrogen fuel cell catalyst of Comparative Example 1 2 Polarization curves of the membrane electrode before and after aging test;

[0037] Figure 6 The 25cm sample was prepared from the platinum-based hydrogen fuel cell catalyst obtained in Example 3. 2 Polarization curves of membrane electrodes. Detailed Implementation

[0038] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] The terms “front,” “back,” “left,” “right,” “inner,” and “outer” used in this specification are merely for clarity of description and are not intended to limit the scope of the invention. Any changes or adjustments to their relative relationships, without substantially altering the technical content, shall also be considered within the scope of the invention.

[0040] In the description of the following embodiments, unless otherwise expressly specified and limited, the term "connection" and other such terms should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an indirect connection through an intermediate medium; it can be the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] Example 1

[0042] Step 1:

[0043] Coconut shell biomass char SC-104 was dried in a vacuum drying oven at 80℃ for 2 hours. Then, 2.0g of the dried biomass char was weighed and placed in an open tube furnace for stepwise gradient temperature oxidation treatment. The specific steps of the treatment were as follows:

[0044] First stage: Treat at 200℃ for 1 hour;

[0045] Second stage: Treat at 300℃ for 1 hour;

[0046] Third stage: Treat at 400℃ for 20 minutes.

[0047] Step 2:

[0048] Prepare a 150 mL alcohol-water mixture by thoroughly mixing 75 mL of deionized water and 75 mL of ethylene glycol. Weigh 0.5 g of the biomass carbon oxidized in step 1 and add it to the 150 mL alcohol-water mixture in two portions. Each time, stir and sonicate to ensure uniform dispersion of the carbon carrier in the mixture. The stirring and sonication process involves stirring for 20 minutes, followed by sonication for 10 minutes, and repeating this process multiple times until a uniformly mixed carbon carrier dispersion is formed.

[0049] Step 3:

[0050] Prepare an alcohol-water mixture by thoroughly mixing 75 mL of deionized water and 75 mL of ethylene glycol. Weigh 1.87 g of chloroplatinic acid and dissolve it in 150 mL of the alcohol-water mixture, stirring continuously during the dissolution process until the platinum salt is uniformly dissolved and dispersed to obtain a platinum salt solution.

[0051] It is important to note that steps 1 and 2, which involve preparing the carbon support dispersion, and step 3, which involves preparing the platinum salt solution, are two completely independent sub-steps. There is no requirement for the order of these two processes; either step can be performed first, or both can be carried out in parallel.

[0052] Step 4:

[0053] The carbon support dispersion prepared in step 2 and the platinum salt solution prepared in step 3 were mixed and then stirred for 20 minutes and sonicated for 10 minutes to ensure uniform mixing.

[0054] Simultaneously, the pH value of the mixed solution was adjusted multiple times using 1M NaOH solution until the pH reached 9. The mixed solution should be thoroughly stirred before each measurement.

[0055] Step 5:

[0056] Pour the pH-adjusted mixed solution into a three-necked flask, equip it with a reflux condenser, and use an oil bath for stepwise gradient heating and reduction. The treatment steps are as follows:

[0057] First stage: Treat at 60℃ for 1 hour;

[0058] Second stage: Treat at 75℃ for 1 hour;

[0059] Third stage: Treat at 90℃ for 1 hour.

[0060] During the reduction process described above, nitrogen gas needs to be used for protection above the surface of the mixture, and the solution needs to be continuously stirred.

[0061] Step 6:

[0062] The catalyst mixture obtained in step 5 was filtered and washed multiple times and then dried under vacuum to finally obtain the platinum-based hydrogen fuel cell catalyst.

[0063] ICP test results show that this embodiment can obtain a platinum-based hydrogen fuel cell catalyst with a Pt loading of 60.5%. Figure 1 The XRD curves confirmed that the average particle size of the Pt particles was 2.4 nm.

[0064] Example 2

[0065] Step 1:

[0066] Ketzan black carbon EC-300J was dried in a vacuum drying oven at 80℃ for 2 hours. Then, 2.0g of the dried Ketzan black carbon was weighed and placed in an open tube furnace for stepwise gradient temperature oxidation treatment. The treatment steps were as follows:

[0067] First stage: Treat at 150℃ for 2 hours;

[0068] Second stage: Treat at 250℃ for 2 hours;

[0069] Third stage: Treat at 350℃ for 40 minutes.

[0070] Step 2:

[0071] Prepare an alcohol-water mixture by thoroughly mixing 100 mL of deionized water and 100 mL of ethylene glycol. Weigh 1.0 g of Ketjen black carbon oxidized in step 1 and add it to 200 mL of alcohol-water mixture in two portions. Each time, stir and sonicate to ensure that the carbon support is evenly dispersed in the mixture. The stirring and sonication process includes stirring for 30 minutes and then sonicating for 20 minutes, and repeating this process multiple times until a uniformly mixed carbon support dispersion is formed.

[0072] Step 3:

[0073] Prepare an alcohol-water mixture by thoroughly mixing 100 mL of deionized water and 100 mL of ethylene glycol. Weigh 1.96 g of platinum nitrate and dissolve it in 200 mL of the alcohol-water mixture, stirring continuously until the platinum salt is uniformly dissolved and dispersed to obtain a platinum salt solution.

[0074] Step 4:

[0075] The carbon support dispersion prepared in step 2 and the platinum salt solution prepared in step 3 were mixed and then stirred for 30 minutes and sonicated for 20 minutes to ensure uniform mixing.

[0076] Simultaneously, the pH value of the mixed solution was adjusted multiple times using 1M NaOH solution until the pH reached 8. The mixed solution should be thoroughly stirred for each measurement.

[0077] Step 5:

[0078] Pour the pH-adjusted mixed solution into a three-necked flask, equip it with a reflux condenser, and use an oil bath for stepwise gradient heating and reduction. The treatment steps are as follows:

[0079] First stage: Treat at 65℃ for 1.5 hours;

[0080] Second stage: Treat at 80℃ for 1.5 hours;

[0081] Third stage: Treat at 95℃ for 1.5 hours.

[0082] During the reduction process described above, nitrogen gas needs to be used for protection above the surface of the mixture, and the solution needs to be continuously stirred.

[0083] Step 6:

[0084] The catalyst mixture obtained in step 5 was filtered and washed multiple times and then dried under vacuum to finally obtain the platinum-based hydrogen fuel cell catalyst.

[0085] ICP testing showed a Pt loading of 49.8%, and XRD analysis revealed an average particle size of 2.2 nm for the catalyst in Example 2. Figure 2 The TEM images shown indicate that the Pt particles have good dispersibility.

[0086] Example 3

[0087] Step 1:

[0088] Mesoporous carbon CN-502 was dried in a vacuum drying oven at 80℃ for 2 hours. Then, 2.0 g of the dried mesoporous carbon was weighed and placed in an open tube furnace for stepwise gradient temperature oxidation treatment. The treatment steps were as follows:

[0089] First stage: Treat at 175℃ for 1.5 hours;

[0090] Second stage: Treat at 275℃ for 1.5 hours;

[0091] Third stage: Treat at 375℃ for 30 minutes.

[0092] Step 2:

[0093] Prepare an alcohol-water mixture by thoroughly mixing 125 mL of deionized water and 125 mL of ethylene glycol. Weigh 1.0 g of the mesoporous carbon oxidized in step 1 and add it to 250 mL of alcohol-water mixture in two portions. Each time, stir and sonicate to ensure that the carbon support is uniformly dispersed in the mixture. The stirring and sonication process includes stirring for 30 minutes and then sonicating for 20 minutes, and repeating this process multiple times until a uniformly mixed carbon support dispersion is formed.

[0094] Step 3:

[0095] Prepare an alcohol-water mixture by thoroughly mixing 125 mL of deionized water and 125 mL of ethylene glycol. Weigh 1.36 g of platinum tetrachloride and dissolve it in 250 mL of the alcohol-water mixture, stirring continuously until the platinum salt is uniformly dissolved and dispersed to obtain a platinum salt solution.

[0096] Step 4:

[0097] The carbon support dispersion prepared in step 2 and the platinum salt solution prepared in step 3 were mixed and then stirred for 30 minutes and sonicated for 20 minutes to ensure uniform mixing.

[0098] Simultaneously, the pH value of the mixed solution was adjusted multiple times using 1M NaOH solution until the pH reached 10. The mixed solution should be thoroughly stirred for each measurement.

[0099] Step 5:

[0100] Pour the pH-adjusted mixed solution into a three-necked flask, equip it with a reflux condenser, and use an oil bath for stepwise gradient heating and reduction. The treatment steps are as follows:

[0101] First stage: Treat at 55℃ for 2 hours;

[0102] Second stage: Treat at 70℃ for 2 hours;

[0103] Third stage: Treat at 85℃ for 2 hours.

[0104] During the reduction process described above, argon gas must be used for protection above the surface of the mixture, and the solution must be continuously stirred.

[0105] Step 6:

[0106] The catalyst mixture obtained in step 5 was filtered and washed multiple times and then dried under vacuum to finally obtain the platinum-based hydrogen fuel cell catalyst.

[0107] Characterization by ICP and XRD confirmed that the catalyst had a Pt loading of 40.2% and an average particle size of 2.1 nm. Figure 6 The membrane electrode prepared by this catalyst can achieve a performance of 0.635V@50A.

[0108] Comparative Example 1

[0109] It was prepared using the same method as in Example 1. The difference was that the carbon support oxidation treatment was performed at a single step at 400°C for 2 hours.

[0110] 25 cm⁻¹ of catalysts obtained in Example 1 and Comparative Example 1 were prepared using the catalysts obtained in Example 1 and Comparative Example 1, respectively. 2 Membrane electrode, membrane electrode performance such as Figure 4 and Figure 5 As shown. The membrane electrode performance (MEA) of the catalyst in Example 1 was 0.651V@50A, and that of the catalyst in Comparative Example 1 was 0.644V@50A. According to the standards published by the U.S. Department of Energy (DOE), the voltage drop at 20A for this area of ​​membrane electrode after accelerated aging testing reflects the catalyst stability. After 10,000 cycles of accelerated aging, the MEA performance of the catalyst in Example 1 decreased by only 5mV@20A, while that of the catalyst in Comparative Example 1 decreased by 11mV@20A under the same conditions. The accelerated aging test was conducted by applying additional square wave voltages of 0.6V (3s) and 0.95V (3s).

[0111] Therefore, it can be seen that after multi-step oxidation treatment of carbon support, the oxygen-containing functional groups on the surface of carbon support are more abundant, the interaction between Pt particles and carbon support is strengthened, and the overall stability of the catalyst is improved.

[0112] Stepwise gradient oxidation, through precise temperature control, can introduce suitable types and quantities of oxygen-containing functional groups (such as carboxyl, hydroxyl, and carbonyl groups) onto the surface of various carbon supports (including but not limited to biomass carbon, Ketjen black, mesoporous carbon, and Cabot carbon black). These functional groups act as anchoring sites, and their interaction mechanism with platinum ions is universal. Those skilled in the art will understand that carbon supports such as Cabot carbon black (e.g., the most commonly used Vulcan XC-72) belong to the same class of conductive carbon black supports as the biomass carbon, mesoporous carbon, and Ketjen black carbon described in the specification. They share similar uses, physicochemical properties (such as high specific surface area and excellent conductivity), and modification requirements in fuel cell catalyst applications.

[0113] All these carbon supports share the same core function as catalyst supports: providing support and a conductive network for platinum particles. Therefore, after undergoing the same stepwise gradient temperature oxidation treatment, their interaction mechanism with metallic platinum is essentially consistent. The goal and principle of this process (introducing functional groups to the surface through temperature control) are universal for conventional carbon supports in this field.

[0114] Therefore, based on common knowledge, those skilled in the art can select other common carbon supports in the field for stepwise gradient heating oxidation treatment according to their needs, and can clearly predict that the selected carbon support will achieve the effect of "richer surface oxygen-containing functional groups" after treatment.

[0115] Comparative Example 2

[0116] The same process as in Example 2 was used for preparation. The difference was that the reduction temperature was 90°C and the time was 3 hours; this method was a single-step solvothermal reduction method.

[0117] The ICP test results of the obtained catalyst showed the same Pt ​​loading as in Example 2, both being 49.8%. Figure 1 The XRD curves show that, compared to Example 2, by changing the multi-step solvothermal reduction method to a single-step solvothermal reduction method, the particle size of the platinum-based hydrogen fuel cell catalyst increased to 3.0 nm, indicating that the multi-step solvothermal reduction method is beneficial for achieving uniform loading of Pt particles and achieving a smaller particle size. The RDE test results of Example 2 and Comparative Example 2 are as follows: Figure 3 As shown, the catalyst prepared by the multi-step solvothermal reduction method has higher mass activity (0.229 A / mg), which is an improvement over the single-step solvothermal reduction method (0.181 A / mg).

[0118] Therefore, the multi-step solvothermal reduction method is beneficial for controlling the nucleation rate, uniformity, and dispersion of Pt seed particles, thereby improving the performance of the catalyst.

[0119] The stepwise gradient reduction process regulates the nucleation and growth rates by controlling reduction kinetics. This mechanism is generally applicable to various soluble platinum salt precursors (such as chloroplatinic acid, platinum nitrate, platinum tetrachloride, and ammonium chloroplatinate). The examples in this specification specifically implement three platinum salts: chloroplatinic acid, platinum nitrate, and platinum tetrachloride. Although their anions differ (e.g., Cl...),... - NO3 - However, they all play the same role in the process of this invention. In both ethylene glycol solvent systems and alkaline conditions, the core reaction of all these platinum salts is the platinum ion (Pt) reaction. 4+ or Pt 2+ It is reduced to zero-valent platinum (Pt) 0 This process involves thermal reduction, ultimately producing metallic platinum. The stepwise gradient thermal reduction method is designed to precisely control the kinetics of this reduction process. This mechanism is applicable to various soluble platinum salts, and its effectiveness is independent of any specific anion.

[0120] For those skilled in the art, when the stepwise gradient reduction method described in the specification has been verified to be effective on platinum salts of various anions, the technical effects that can be obtained by applying this method to other conventional members of this type of platinum source (such as ammonium chloroplatinate) are reasonably foreseeable.

[0121] Therefore, other commonly used platinum salts, such as ammonium chloroplatinate, have decomposition temperature ranges that match the gradient reduction temperature range (55-95°C) used in this invention. Those skilled in the art can reasonably foresee that the same gradient heating program can also effectively control the reduction rate and obtain the desired small-diameter platinum particles.

[0122] The foregoing embodiments have provided a detailed description of the inventive intent and implementation of the present invention. However, those skilled in the art will understand that the above embodiments are merely preferred embodiments of the present invention. Due to space limitations, not all embodiments can be listed here. Any implementation that embodies the technical solution of the claims of the present invention is within the protection scope of the present invention.

[0123] It should be noted that the above content is a further detailed description of the present invention in conjunction with specific embodiments, and it should not be considered that the specific embodiments of the present invention are limited to this. Under the guidance of the above embodiments, those skilled in the art can make various improvements and modifications based on the above embodiments, and these improvements or modifications fall within the protection scope of the present invention.

Claims

1. A method for preparing a platinum-based hydrogen fuel cell catalyst, characterized in that, Includes the following steps: S1. Carrier Pretreatment and Dispersion: The carbon carrier is subjected to stepwise gradient temperature oxidation treatment in air atmosphere, and then the oxidized carbon carrier is dispersed in ethylene glycol aqueous solution a, and mixed evenly to obtain a uniform carbon carrier dispersion; the stepwise gradient temperature oxidation treatment includes the following steps: First stage: Treat at 150~200℃ for 1~2 hours; Second stage: Treat at 250~300℃ for 1~2 hours; Third stage: Treat at 350~400℃ for 20~40 minutes; Preparation of platinum salt solution: Disperse platinum salt in ethylene glycol aqueous solution b, and mix thoroughly to obtain a homogeneous platinum salt solution; S2. Mix the carbon support dispersion obtained in step S1 with the platinum salt solution, and adjust the pH value to 8-10 with alkali solution to obtain a uniformly mixed reaction solution. S3. The mixed reaction solution is subjected to stepwise gradient heating reduction treatment under inert gas protection; S4. The product obtained in step S3 is filtered, washed and vacuum dried to obtain the platinum-based hydrogen fuel cell catalyst.

2. The method for preparing a platinum-based hydrogen fuel cell catalyst as described in claim 1, characterized in that: The carbon carrier is selected from at least one of biomass carbon, Cabot carbon black, mesoporous carbon, and Ketjen black carbon.

3. The method for preparing a platinum-based hydrogen fuel cell catalyst as described in claim 1, characterized in that: In both the ethylene glycol aqueous solutions a and b, water accounts for 50% of the volume.

4. The method for preparing a platinum-based hydrogen fuel cell catalyst as described in claim 1, characterized in that: The platinum salt is selected from at least one of platinum tetrachloride, chloroplatinic acid, platinum nitrate, and ammonium chloroplatinate.

5. The method for preparing a platinum-based hydrogen fuel cell catalyst as described in claim 1, characterized in that: The uniform mixing in steps S1 and S2 is achieved by mechanical stirring, ultrasonic treatment, or a combination thereof.

6. The method for preparing a platinum-based hydrogen fuel cell catalyst as described in claim 1, characterized in that, The stepwise gradient heating reduction in step S3 includes the following steps: First stage: React at 55~65℃ for 1~2 hours; Second stage: React at 70~80℃ for 1~2 hours; Third stage: Reaction at 85~95℃ for 1~2 hours.

7. The method for preparing a platinum-based hydrogen fuel cell catalyst as described in claim 1, characterized in that... The inert gas mentioned in step S3 is nitrogen or argon.

8. A platinum-based hydrogen fuel cell catalyst prepared by any one of claims 1 to 7, characterized in that: The catalyst has a platinum loading of 40-60 wt% and an average platinum particle size of 2-3 nm.

9. The application of the platinum-based hydrogen fuel cell catalyst as described in claim 8 in the membrane electrode assembly of a hydrogen fuel cell.

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