Hydrophobic catalyst as well as preparation method and application thereof
By uniformly coating the surface of the Pt-based catalyst with an ionic liquid to form a hydrophobic microenvironment, the problem of Pt-based catalysts being susceptible to water interference is solved, thereby improving catalytic activity and oxygen mass transfer capacity, making it suitable for commercial applications of PEMFCs.
Patent Information
- Application Number
- CN202511113315.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-11
- Publication Date
- 2025-11-11
AI Technical Summary
Existing Pt-based catalysts have low catalytic activity, are easily affected by water, and are easy to prepare, which leads to a decline in the performance of PEMFCs.
A hydrophobic catalyst is prepared by uniformly coating the surface of a Pt-based catalyst with an ionic liquid to form a hydrophobic microenvironment, thereby avoiding blockage of the Pt active centers and improving oxygen mass transfer capacity and catalytic activity.
It improves the catalytic activity and oxygen solubility of the oxygen reduction reaction, enhances the performance of the membrane electrode, and is suitable for the commercial application of PEMFC.
Smart Images
Figure CN120933385A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a hydrophobic catalyst, its preparation method, and its application. Background Technology
[0002] Proton exchange membrane fuel cells (PEMFCs), as a highly efficient and clean energy conversion device, have attracted widespread attention due to their advantages such as wide availability of fuel sources, high energy conversion efficiency, and no environmental pollution. However, the commercial application of PEMFCs still faces many challenges, the most critical of which is the slow kinetics of the cathode oxygen reduction reaction (ORR). To improve the performance of PEMFCs, the development of efficient and durable electrocatalysts has become a key research focus.
[0003] Currently, carbon-supported platinum-based (Pt / C) catalysts are the most commonly used ORR catalysts in PEMFCs. However, Pt-based catalysts also have problems that need improvement, such as the scarcity and high cost of Pt resources, insufficient activity and durability of Pt-based catalysts, and susceptibility to interference from reaction water during the reaction process, leading to blockage of active sites, increased mass transfer resistance, and further reduction in catalytic efficiency. To overcome these problems, researchers have proposed various improvement strategies. For example, alloying Pt with transition metals (such as Co and Ni), adjusting the electronic structure of the catalyst, optimizing the exposure of active crystal faces, and introducing functional modification materials can all improve the utilization rate and catalytic activity of Pt.
[0004] Although the above methods have improved the performance of Pt-based catalysts to some extent, the following problems still exist: uneven coating when using ionic liquids for modification, hydrophilic catalysts are easily affected by water, and the synthesis efficiency is low and the cost is high.
[0005] Therefore, it is essential to design a hydrophobic catalyst with high catalytic activity, low susceptibility to water interference, and simple preparation method for the commercial application of PEMFC. Summary of the Invention
[0006] The technical problem this invention aims to solve is to overcome the shortcomings of existing Pt-based catalysts, such as low catalytic activity, susceptibility to water interference, and simple preparation methods. This invention provides a hydrophobic catalyst, its preparation method, and its applications. In this invention, an ionic liquid is uniformly coated onto the surface of a Pt-based catalyst. When the resulting hydrophobic catalyst is further applied to an electrode, it can form a hydrophobic microenvironment, repelling interfacial water and preventing blockage of Pt active sites. This not only improves the catalytic activity of the ORR process but also enhances oxygen mass transfer capacity, increases oxygen solubility, and improves membrane electrode performance. The preparation method of this invention is simple and convenient, and suitable for the commercial application of PEMFCs.
[0007] The present invention solves the above-mentioned technical problems through the following technical solutions.
[0008] This invention provides a method for preparing a hydrophobic catalyst, which includes the following steps: subjecting a mixture comprising a Pt-based catalyst, an ionic liquid, and an organic alcohol solvent to ultrasonication and rotary evaporation in sequence to obtain a hydrophobic catalyst; wherein the ionic liquid is 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.
[0009] In this invention, the mass ratio of the Pt-based catalyst to the ionic liquid can be 1:(0.02-3), for example 10:1.
[0010] In this invention, the mass-to-volume ratio of the Pt-based catalyst to the organic alcohol solvent can be 1 mg:(0.1-0.5) mL, for example, 1 mg:0.2 mL.
[0011] In this invention, the mixture may also include a binder.
[0012] The binder is preferably an ionomer, such as a Nafion solution.
[0013] The preferred mass-to-volume ratio of the Pt-based catalyst to the binder is 1 mg:(0.01-0.1) mL, for example, 1:0.05 mL.
[0014] In this invention, the temperature of the ultrasound can be room temperature, preferably 15-35℃, for example 25℃.
[0015] In this invention, the duration of the ultrasound can be 2-4 hours, for example, 3 hours.
[0016] The present invention employs rotary evaporation, which allows the organic alcohol solvent to continuously evaporate from the suspension, ensuring that the ionic liquid is completely coated on the catalyst surface.
[0017] In this invention, the temperature of the rotary evaporation can be 45-65°C, for example 55°C.
[0018] In this invention, the rotary evaporation may further include a drying step.
[0019] Preferably, the drying is performed using a vacuum drying method.
[0020] The vacuum drying temperature can be room temperature, preferably 15-35℃, for example 25℃.
[0021] The vacuum drying time can be 24-48 hours, for example, 36 hours.
[0022] In this invention, the Pt-based catalyst may be selected from the Pt / C catalyst.
[0023] In this invention, the organic alcohol solvent may be selected from one or more of ethylene glycol, isopropanol, and butanediol.
[0024] In this invention, the ionic liquid can be prepared by the following method: a mixture comprising 1-methylimidazolium, 1-bromobutane and an organic solvent is heated and reacted, followed by washing to obtain 1-butyl-3-methylimidazolium bromide; then, 1-butyl-3-methylimidazolium bromide, lithium bis(trifluoromethanesulfonyl)imide and deionized water are reacted at room temperature to obtain 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.
[0025] The molar ratio of 1-methylimidazole to 1-bromobutane can be 1:(0.5-2), for example, 1:1.
[0026] The organic solvent may be acetonitrile and / or isopropanol.
[0027] The molar volume ratio of the 1-methylimidazole to the organic solvent can be 1 mol:(100-300) mL, for example, 1 mol:200 mL.
[0028] The temperature of the heating reaction can be 60-80℃, for example 70℃.
[0029] The heating reaction time can be 12-48 hours, for example, 24 hours.
[0030] The washing process can be performed using ethyl acetate.
[0031] The washing process may also include a drying step.
[0032] Preferably, the drying is performed using a vacuum drying method.
[0033] The vacuum drying temperature can be room temperature, preferably 50-80℃, for example 60℃.
[0034] The vacuum drying time can be 12-48 hours, for example, 24 hours.
[0035] The molar ratio of the 1-butyl-3-methylimidazolium bromide to the lithium bis(trifluoromethanesulfonylimide) can be 1:(0.5-2), for example, 1:1.05.
[0036] The molar volume ratio of the 1-butyl-3-methylimidazolium bromide to the deionized water can be 1 mol:(100-300) mL, for example, 1 mol:250 mL.
[0037] The reaction time at room temperature can be 10-20 hours, for example, 14 hours.
[0038] The reaction at room temperature may further include one or more of the following steps: adding dichloromethane to separate the layers, washing, removing bromide ions, or drying.
[0039] Preferably, the washing process uses deionized water.
[0040] Preferably, the removal of bromide ions is performed by titrating a saturated AgNO3 solution.
[0041] Preferably, the drying is performed using a vacuum drying method.
[0042] The vacuum drying temperature can be room temperature, preferably 50-80℃, for example 60℃.
[0043] The vacuum drying time can be 12-48 hours, for example, 24 hours.
[0044] The present invention also provides a hydrophobic catalyst, which is prepared by the method described above for preparing hydrophobic catalysts.
[0045] The present invention also provides a hydrophobic catalyst, which has a core-shell structure, comprising a core and a shell, wherein the core is a Pt-based catalyst and the shell is 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; the contact angle of the hydrophobic catalyst is 125-145°.
[0046] In this invention, the contact angle of the hydrophobic catalyst can be 130-140°, for example 135°.
[0047] In this invention, the content of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide can be 5-15 wt%, for example 5 wt% or 10 wt%, where the percentage refers to the mass percentage of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide in the hydrophobic catalyst.
[0048] In this invention, the thickness of the outer shell can be 0.5-1 nm, for example 0.75 nm;
[0049] In this invention, the outer shell may further include an adhesive. The adhesive is preferably an ionomer.
[0050] The present invention also provides a catalyst coated membrane (CCM) comprising a catalyst layer and a proton exchange membrane, wherein the catalyst layer comprises a hydrophobic catalyst as described above.
[0051] The present invention also provides a membrane electrode assembly (MEA) including a gas diffusion layer and a catalyst coating membrane as described above.
[0052] The present invention also provides an application of the hydrophobic catalyst, catalyst-coated membrane, or membrane electrode assembly as described above in a fuel cell.
[0053] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.
[0054] The reagents and raw materials used in this invention are all commercially available.
[0055] The positive and progressive effects of this invention are as follows:
[0056] This invention uniformly coats the surface of a Pt-based catalyst with an ionic liquid. When the resulting hydrophobic catalyst is further applied to an electrode, it can form a hydrophobic microenvironment, repel interfacial water, and avoid blockage of Pt active centers. This not only improves the catalytic activity of the ORR process but also enhances oxygen mass transfer capacity, increases oxygen solubility, and improves membrane electrode performance.
[0057] The preparation method of this invention is simple and convenient, and is suitable for the commercial application of PEMFC. Attached Figure Description
[0058] Figure 1 This is a schematic diagram of the catalyst in Example 1 before and after coating. Figure 1 Part a represents the catalyst before coating. Figure 1 Part b is a schematic diagram of the structure of the catalyst prepared in Example 1. Figure 1 Part c is a schematic diagram of the surface structure of the hydrophobic catalyst prepared in Example 1.
[0059] Figure 2 TEM images of the catalysts in Comparative Example 1 and Example 1 are shown. Figure 2 Part a is a TEM image of the catalyst in Comparative Example 1. Figure 2 Part b is a TEM image of the catalyst from Example 1.
[0060] Figure 3 The images show contact angle measurements of the catalysts in Examples 1 and 2, and Comparative Examples 1 and 2. Figure 3 Part a is a contact angle measurement diagram of the catalyst in Comparative Example 1. Figure 3 Part b is a contact angle measurement diagram of the catalyst in Comparative Example 2. Figure 3 Part c is the contact angle measurement diagram of the catalyst in Example 2. Figure 3 Part d is a contact angle measurement diagram of the catalyst in Example 1.
[0061] Figure 4 The mass-to-specific activity and area-to-specific activity of the catalysts in Examples 1 and 2, and Comparative Examples 1 and 2 are given.
[0062] Figure 5 The polarization curves are performance graphs of the catalysts in Examples 1 and 2, and Comparative Examples 1 and 2. Detailed Implementation
[0063] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.
[0064] In this invention, the Pt / C (40wt%) catalyst is HiSPEC 40% Pt on Vulcan XC-72R purchased from JM Company.
[0065] Example 1
[0066] (1) Preparation of ionic liquids (ILs)
[0067] Under a nitrogen atmosphere, 0.5 mol of 1-methylimidazolium and 0.5 mol of 1-bromobutane were added to a 500 mL round-bottom flask containing 100 mL of acetonitrile solution. After stirring the reaction at 70 °C for 24 h, the unreacted acetonitrile was removed by rotary evaporation of the reaction product. 1-Butyl-3-methylimidazolium bromide (BMIMBr) was collected, washed three times with ethyl acetate, and then dried under vacuum at 60 °C for 24 h to obtain a yellow liquid.
[0068] 0.4 mol BMIMBr and 0.42 mol lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) were added to a 250 mL round-bottom flask containing 100 mL deionized water. The mixture was stirred at room temperature for 14 h. An appropriate amount of dichloromethane was added, and the mixture was stirred for 3 h. After standing and separating into layers, the dichloromethane phase was collected and washed several times with deionized water until no precipitate was formed when titrated with saturated AgNO3 solution. The mixture was then placed at 60 °C and dried under vacuum for 24 h to obtain a yellow viscous liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMIMTFSI).
[0069] (2) Preparation of hydrophobic catalysts
[0070] 100 mg of ordered Pt / C (40 wt%) catalyst, 20 mL of isopropanol solution, 5 mL of Nafion ionomer solution, and 100 mg of ILs were mixed and sonicated at 25 °C for 3 h. The mixture was then subjected to rotary evaporation at 55 °C to continuously evaporate the isopropanol solvent from the suspension, ensuring complete coating of the ionic liquid onto the catalyst surface. The sample was then vacuum dried at 25 °C for 36 h. A hydrophobic catalyst was obtained, wherein the ionic liquid constituted 10 wt% of the hydrophobic catalyst.
[0071] Example 2
[0072] (1) Preparation of ionic liquids (ILs)
[0073] Same as Example 1.
[0074] (2) Preparation of hydrophobic catalysts
[0075] 100 mg of ordered Pt / C (40 wt%) catalyst, 20 mL of isopropanol solution, 5 mL of Nafion ionomer solution, and 50 mg of ILs were mixed and sonicated at 25 °C for 3 h. Then, the isopropanol solvent was continuously evaporated from the suspension by rotary evaporation at 55 °C to ensure complete coating of the catalyst surface by the ionic liquid. The sample was vacuum dried at 25 °C for 36 h to obtain a hydrophobic catalyst, wherein the ionic liquid constituted 5 wt% of the hydrophobic catalyst.
[0076] Comparative Example 1
[0077] A commercially available Pt / C (40 wt%) catalyst was used directly as Comparative Example 1.
[0078] Comparative Example 2
[0079] (1) Preparation of ionic liquids (ILs)
[0080] Same as Example 1.
[0081] (2) Preparation of hydrophobic catalysts
[0082] The catalyst was obtained by mixing 100 mg of ordered (40 wt%) catalyst, 20 mL of isopropanol solution, 5 mL of ionomer Nafion solution and 100 mg of ILs, and then sonicating at 25 °C for 3 h. The mass percentage of ionic liquid in the hydrophobic catalyst was 10 wt%.
[0083] Example 1 Morphology and Structure
[0084] Figure 1 Part a is a schematic diagram of the structure of a commercially available Pt / C (40wt%) catalyst without ionic liquid coating (i.e., Comparative Example 1). Figure 1 Part b is a schematic diagram of the structure of the hydrophobic catalyst prepared in Example 1. Figure 1 Part c is a schematic diagram of the surface structure of the hydrophobic catalyst prepared in Example 1. As shown in the figure, the hydrophobic catalyst prepared in this invention has a core-shell structure, including a core and an outer shell. The core is a Pt / C (40wt%) catalyst, and the outer shell includes the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and the ionomer Nafion as a binder.
[0085] Figure 2 Part a is a TEM image of the hydrophobic catalyst prepared in Example 1. Figure 2 Part b is a TEM image of the commercially available Pt / C (40 wt%) catalyst of Comparative Example 1. As can be seen from the image, the ionic liquid in Example 1 is uniformly coated on the surface of the Pt / C (40 wt%) catalyst, and the thickness of the ionic liquid is 0.75 nm.
[0086] Example 2: Contact Angle Test
[0087] Contact angles were measured by dropping water onto the catalyst surfaces of Examples 1 and 2, and Comparative Examples 1 and 2. The results are as follows: Figure 3 As shown. Among them, Figure 3 Part a is a contact angle measurement diagram of the catalyst in Comparative Example 1. Figure 3 Part b is a contact angle measurement diagram of the catalyst in Comparative Example 2. Figure 3 Part c is the contact angle measurement diagram of the catalyst in Example 2. Figure 3 Part d is a contact angle measurement diagram of the catalyst in Example 1.
[0088] As can be seen from the figure, the contact angle of the catalyst in Comparative Example 1 is 65.2°, the contact angle of the catalyst in Comparative Example 2 is 87°, and the contact angles of the hydrophobic catalysts in Examples 1 and 2 are increased to 135° and 114°, respectively. It is evident that the catalyst layers in Examples 1 and 2 have better hydrophobicity and performance.
[0089] Effect Example 3 Catalytic Performance
[0090] Catalysts from Examples 1 and 2, and Comparative Examples 1 and 2, were mixed with 5 wt% Nafion solution to prepare catalyst slurries. The catalyst slurries were then uniformly sprayed onto the surface of a Nafion 211 membrane, with a spraying area of 5*5 cm. 2 A cathode catalyst coating film (CCM) is formed. Subsequently, the CCM and carbon paper are hot-pressed to form a membrane electrode assembly (MEA).
[0091] The prepared MEA was tested on an HS330 HEPHAS ENERGY system for mass specific activity (MA), area specific activity (SA), and polarization curves. Specifically, oxygen was continuously bubbled into the electrolyte (Nafion membrane) for 30 minutes, and the rotation speed of the rotating disk electrode was adjusted to 1600 rpm with a scan rate of 10 mV / s. -1 The linear sweep (LSV) curve was measured while the potential was kept between 0.05 and 1.10 V, and MA and SA were obtained according to the Koutecky-Levich (KL) equation.
[0092] Polarization curve test conditions: 0-3 A / cm 2 The humidity of both the cathode and anode is 100%, the stoichiometric ratio of the cathode to the anode is 2:2, the back pressure of the cathode is 140 kPa, the back pressure of the anode is 130 kPa, and the battery temperature is 75℃.
[0093] The results are shown in Table 1. Figure 4 and Figure 5 As shown.
[0094] Table 1
[0095]
[0096] Depend on Figure 4 As shown in Table 1, the ionic liquid-coated ordered Pt / C catalysts of Examples 1 and 2 significantly outperformed the conventional Pt / C catalyst (Comparative Example 1) and the Pt / C catalyst with ordinary ionic liquid mixture (Comparative Example 2) in both mass-to-analyte (MA) and surface-to-analyte (SA) ratios. This is likely because, in this invention, the ionic liquid coating effectively forms a hydrophobic microenvironment, repelling interfacial water and thus preventing the blockage of Pt active centers. This exposure of reactive sites allows for better reaction with oxygen, improving catalytic performance.
[0097] Depend on Figure 5 It can be seen that the peak power density is 1.28 W / cm² for the Pt / C catalyst (Comparative Example 1). 2 The 1.32 W / cm² of a common mixture of Pt / C catalyst and ionic liquid (Comparative Example 2) 2 The growth rate reached 1.36 W / cm² for the Pt / C catalyst coated with 5 wt% ionic liquid (Example 2). 2 The Pt / C catalyst coated with 10 wt% ionic liquid (Example 1) has a strength of 1.52 W / cm². 2 This effectively improves catalytic performance.
Claims
1. A method for preparing a hydrophobic catalyst, characterized in that, The process includes the following steps: a mixture comprising a Pt-based catalyst, an ionic liquid, and an organic alcohol solvent is subjected to ultrasonication and rotary evaporation in sequence to obtain a hydrophobic catalyst; wherein the ionic liquid is 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.
2. The method for preparing the hydrophobic catalyst according to claim 1, characterized in that, The Pt-based catalyst is selected from Pt / C catalysts; And / or, the mass ratio of the Pt-based catalyst to the ionic liquid is 1:(0.02-3), for example 10:1; And / or, the organic alcohol solvent is selected from one or more of ethylene glycol, isopropanol, and butanediol; And / or, the mass-to-volume ratio of the Pt-based catalyst to the organic alcohol solvent is 1 mg:(0.1-0.5) mL, for example, 1 mg:0.2 mL; And / or, the mixture further includes a binder; the binder is preferably an ionomer, such as a Nafion solution; the mass-to-volume ratio of the Pt-based catalyst to the binder is preferably 1 mg:(0.01-0.1) mL, for example 1 mg:0.05 mL; And / or, the temperature of the ultrasound is room temperature, preferably 15-35°C, for example 25°C; And / or, the duration of the ultrasound is 2-4 hours, for example, 3 hours; And / or, the rotary evaporation temperature is 45-65°C, for example 55°C; And / or, the rotary evaporation is followed by a drying step; preferably, the drying is performed by vacuum drying; the vacuum drying temperature is room temperature, preferably 15-35℃, for example 25℃; the vacuum drying time is 24-48h, for example 36h.
3. The method for preparing the hydrophobic catalyst according to claim 1, characterized in that, The ionic liquid is prepared by the following method: A mixture comprising 1-methylimidazolium, 1-bromobutane and an organic solvent was heated and reacted, followed by washing to obtain 1-butyl-3-methylimidazolium bromide; then, 1-butyl-3-methylimidazolium bromide, lithium bis(trifluoromethanesulfonyl)imide and deionized water were reacted at room temperature to obtain 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.
4. The method for preparing the hydrophobic catalyst according to claim 3, characterized in that, The molar ratio of the 1-methylimidazole to the 1-bromobutane is 1:(0.5-2), for example, 1:1; And / or, the organic solvent is acetonitrile and / or isopropanol; And / or, the molar volume ratio of the 1-methylimidazole to the organic solvent is 1 mol:(100-300) mL, for example, 1 mol:200 mL; And / or, the temperature of the heating reaction is 60-80°C, for example 70°C; And / or, the heating reaction time is 12-48 hours, for example, 24 hours; And / or, the washing is performed using ethyl acetate; And / or, the washing process further includes a drying step; preferably, the drying is performed by vacuum drying; the vacuum drying temperature is preferably room temperature, more preferably 50-80℃, for example 60℃; the vacuum drying time is preferably 12-48h, for example 24h; And / or, the molar ratio of the 1-butyl-3-methylimidazolium bromide to the lithium bis(trifluoromethanesulfonyl)imide is 1:(0.5-2), for example 1:1.05; And / or, the molar volume ratio of the 1-butyl-3-methylimidazolium bromide to the deionized water is 1 mol:(100-300) mL, for example 1 mol:250 mL; And / or, the reaction time at room temperature is 10-20 hours, for example, 14 hours; And / or, the reaction at room temperature may further include one or more of the following steps: adding dichloromethane to separate the layers, washing, removing bromide ions, or drying; Preferably, the washing process uses deionized water. Preferably, the removal of bromide ions is performed by titrating a saturated AgNO3 solution; Preferably, the drying is performed using vacuum drying; the vacuum drying temperature is preferably room temperature, more preferably 50-80℃, for example 60℃; the vacuum drying time is preferably 12-48h, for example 24h.
5. A hydrophobic catalyst, characterized in that, It is prepared by the method of any one of claims 1-4 for preparing the hydrophobic catalyst.
6. A hydrophobic catalyst, characterized in that, The hydrophobic catalyst has a core-shell structure, comprising a core and an outer shell. The core is a Pt-based catalyst, and the outer shell is 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide. The contact angle of the hydrophobic catalyst is 125-145°.
7. The hydrophobic catalyst according to claim 6, characterized in that, The contact angle of the hydrophobic catalyst is 130-140°, for example 135°; And / or, the content of the 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide is 5-15 wt%, for example 5 wt% or 10 wt%, where the percentage refers to the mass percentage of the 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide in the hydrophobic catalyst; And / or, the thickness of the outer shell is 0.5-1 nm, for example 0.75 nm; And / or, the housing also includes an adhesive; the adhesive is preferably an ionomer.
8. A catalyst coating film, characterized in that, It includes a catalyst layer and a proton exchange membrane, wherein the catalyst layer comprises a hydrophobic catalyst as described in any one of claims 5-7.
9. A membrane electrode assembly, characterized in that, It includes a gas diffusion layer and a catalyst coating film as described in claim 8.
10. The application of a hydrophobic catalyst as described in any one of claims 5-7, a catalyst coating membrane as described in claim 8, or a membrane electrode assembly as described in claim 9 in a fuel cell.