Carbon-supported platinum-based catalysts and methods for their preparation, membrane electrodes and fuel cells

Abstract

The application discloses a carbon-supported platinum-based catalyst and a preparation method thereof, a membrane electrode and a fuel cell. The preparation method comprises the following steps: providing a carbon carrier, a platinum source, a reducing agent and a first solvent, mixing to obtain a precursor solution; performing microwave heating on the precursor solution to obtain a carbon-supported platinum-based catalyst precursor; mixing the carbon-supported platinum-based catalyst precursor with a hydrophobic agent, and performing hydrothermal reaction to obtain a carbon-supported platinum-based catalyst. The carbon-supported platinum-based catalyst prepared by the preparation method has good surface hydrophobicity, which is beneficial to effective three-phase contact of O2, H2O and the carbon-supported platinum-based catalyst. Therefore, a catalyst layer comprising the carbon-supported platinum-based catalyst has good drainage capacity and working performance under a high current density. In addition, the preparation method has simple process and good reproducibility, and the carbon-supported platinum-based catalyst prepared by the preparation method has uniform particle size and uniform distribution, and is suitable for large-scale industrial production.

Description

Technical Field

[0001] This application relates to the field of fuel cell catalyst technology, and more particularly to a method for preparing a carbon-supported platinum-based catalyst, a carbon-supported platinum-based catalyst obtained by the method, a membrane electrode assembly including the carbon-supported platinum-based catalyst, and a fuel cell including the membrane electrode assembly. Background Technology

[0002] Proton exchange membrane fuel cells (PEMFCs) use a proton-conducting polymer membrane as an electrolyte. They are power generation devices that directly convert chemical energy into electrical energy. They have advantages such as zero emissions, no pollution, high efficiency, and low noise, and have broad application prospects and huge market potential in the field of automotive power supplies.

[0003] The membrane electrode assembly (MEA) is the core component of a PEMFC, mainly composed of an anode catalyst layer, a proton exchange membrane, and a cathode catalyst layer. During PEMFC power generation, water is generated, and existing catalyst layers readily absorb water. If this water is not drained promptly, it can clog the anode and / or cathode catalyst layers, hindering the contact between the reactant gases and the catalyst, leading to a decrease in fuel cell power, performance degradation, or even shutdown. Therefore, effective water management is crucial for improving PEMFC performance and extending its lifespan.

[0004] Currently, the drainage performance of PEMFCs is mainly optimized from the following aspects: bipolar plate flow channel structure design, gas diffusion layer pore structure design, catalyst layer internal structure design, and battery operating parameters. Although these design optimizations can improve water management inside PEMFCs, they also increase the structural complexity of PEMFCs and increase manufacturing costs, which is not conducive to the industrialization of PEMFCs. Summary of the Invention

[0005] In view of this, this application provides a method for preparing a carbon-supported platinum-based catalyst, which aims to improve the hydrophobicity of existing carbon-supported platinum-based catalysts.

[0006] The embodiments of this application are implemented as follows: a method for preparing a carbon-supported platinum-based catalyst includes:

[0007] A carbon support, a platinum source, a reducing agent, and a first solvent are provided and mixed to obtain a precursor solution.

[0008] The precursor solution was microwave heated to obtain a carbon-supported platinum-based catalyst precursor;

[0009] The carbon-supported platinum-based catalyst precursor was mixed with a hydrophobic agent and subjected to a hydrothermal reaction to obtain the carbon-supported platinum-based catalyst.

[0010] Optionally, the carbon support is selected from at least one of carbon black, carbon nanotubes, graphitic carbon, and graphene; and / or

[0011] The platinum source is selected from at least one of H2PtCl6, K2PtCl6, K2PtCl4, Na2PtCl4, (NH4)2PtCl6, and Pt(NO3)2; and / or

[0012] The reducing agent is selected from at least one of oleylamine, oleic acid, 1-octadecene, TBAB, iron carbonyl and cobalt carbonyl; and / or

[0013] The first solvent is selected from at least one of ethylene glycol, isopropanol, and glycerol; and / or

[0014] The hydrophobic agent is selected from at least one of n-butyl mercaptan, n-dodecyl mercaptan, and n-hexadecyl mercaptan.

[0015] Optionally, the average particle size of the carbon support is 40–200 nm.

[0016] Optionally, the concentration of the carbon support in the precursor solution is 0.004–0.012 g / mL; and / or

[0017] In the precursor solution, the concentration of the platinum source is 0.008–0.06 g / mL; and / or

[0018] In the precursor solution, the concentration of the reducing agent is 0.2–1.2 g / mL; and / or

[0019] The molar ratio of the carbon-supported platinum-based catalyst precursor to the hydrophobic agent is 5:(0.8-1.2).

[0020] Optionally, the microwave heating includes: heating the precursor solution to a first temperature with a first microwave power, stopping the microwave heating for a period of time t1, and then microwave heating with a second microwave power for a period of time t2.

[0021] Optionally, the first microwave power is 1200–3000 W; and / or

[0022] The first temperature is 130–180°C; and / or

[0023] The time t1 is 5–20 min; and / or

[0024] The second microwave power is 500–1000W; and / or

[0025] The time t2 is 2 to 10 minutes.

[0026] Optionally, the temperature of the hydrothermal reaction is 100–200°C; and / or

[0027] The hydrothermal reaction takes 10–24 hours.

[0028] Optionally, the process after microwave heating further includes: washing the microwave-heated product until the conductivity of the filtrate is less than or equal to 10 μS / cm; and / or

[0029] The process after the hydrothermal reaction also includes: washing the product of the hydrothermal reaction with a detergent until the conductivity of the filtrate is less than or equal to 10 μS / cm.

[0030] Optionally, the provision of the carbon support, platinum source, reducing agent, and first solvent further includes: providing a doped metal source.

[0031] Optionally, the doped metal source is selected from at least one of Ru, Pd, Rh, Ir, Ni, Co, Mn, Cu, Sn, V, Ga, and Mo sources; and / or

[0032] The molar ratio of Pt in the platinum source to M in the doped metal source is Pt:M = x:y, where x > 0, y > 0, and x + y ≤ 100.

[0033] Accordingly, this application also provides a carbon-supported platinum-based catalyst, which is prepared by the above-described preparation method.

[0034] Optionally, the metal loading of the carbon-supported platinum-based catalyst is 40–70 wt%.

[0035] Accordingly, this application also provides a membrane electrode comprising the above-mentioned carbon-supported platinum-based catalyst.

[0036] Accordingly, this application also provides a fuel cell comprising the above-mentioned carbon-supported platinum-based catalyst.

[0037] The carbon-supported platinum-based catalyst prepared by the method described in this application exhibits good surface hydrophobicity, which facilitates effective three-phase contact between O2, H2O, and the carbon-supported platinum-based catalyst. Thus, the catalyst layer of the membrane electrode assembly, including the carbon-supported platinum-based catalyst, possesses excellent water drainage capacity and high-current-density performance. Furthermore, the preparation method described in this application is simple, reproducible, and produces carbon-supported platinum-based catalyst particles with uniform size and distribution, making it suitable for large-scale industrial production. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1This is a flowchart of a method for preparing a carbon-supported platinum-based catalyst provided in this application;

[0040] Figure 2 This is a scanning electron microscope image of the Pt / C catalyst of Example 1 of this application;

[0041] Figure 3 This is a schematic diagram of the contact angle of the membrane electrode prepared by the catalysts in Examples 1, 2, and the comparative examples of this application;

[0042] Figure 4 These are polarization curves of the membrane electrodes in Example 1 and the comparative example. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0044] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operation, specifically the orientation shown in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to".

[0045] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0046] Please see Figure 1 This application provides a method for preparing a carbon-supported platinum-based catalyst, comprising the following steps:

[0047] Step S1: Provide carbon support, platinum source, reducing agent and first solvent, mix them to obtain precursor solution;

[0048] Step S2: Microwave heating the precursor solution to obtain a carbon-supported platinum-based catalyst precursor;

[0049] Step S3: Mix the carbon-supported platinum-based catalyst precursor with a hydrophobic agent and perform a hydrothermal reaction to generate hydrophobic groups on the surface of the carbon-supported platinum-based catalyst precursor, thereby obtaining a carbon-supported platinum-based catalyst.

[0050] In step S1:

[0051] The carbon support may be selected from, but is not limited to, at least one of carbon black, carbon nanotubes, graphitic carbon, and graphene.

[0052] In some embodiments, the carbon support has an average particle size of 40–200 nm. Within this particle size range, the carbon support exhibits excellent electrical conductivity and is beneficial for platinum loading.

[0053] The platinum source may be selected from, but is not limited to, at least one of H₂PtCl₆, K₂PtCl₆, K₂PtCl₄, Na₂PtCl₄, (NH₄)₂PtCl₆, and Pt(NO₃)₂. It is understood that the platinum source may also be a hydrate of the above compounds, such as Na₂PtCl₄·H₂O.

[0054] The reducing agent may be selected from, but is not limited to, at least one of oleylamine, oleic acid, 1-octadecene, TBAB, carbonyl iron, and carbonyl cobalt.

[0055] The first solvent may be selected from, but is not limited to, alcohol solvents. In some embodiments, the alcohol solvent may be selected from, but is not limited to, at least one of ethanol, ethylene glycol, isopropanol, and glycerol.

[0056] In the precursor solution, the concentration of the carbon support is 0.004–0.012 g / mL.

[0057] In the precursor solution, the concentration of the platinum source is 0.008–0.06 g / mL.

[0058] In the precursor solution, the concentration of the reducing agent is 0.2–1.2 g / mL.

[0059] In some embodiments, a carbon support, a platinum source, a reducing agent, and a first solvent are provided and mixed to obtain a precursor solution, comprising:

[0060] Step S11: Provide a platinum source and disperse the platinum source in a first solvent to obtain a platinum source solution;

[0061] Step S12: Provide a carbon support and disperse the carbon support in the platinum source solution to obtain a platinum carbon solution;

[0062] Step S13: Add a reducing agent to the platinum carbon solution to obtain the precursor solution.

[0063] In some embodiments, dispersing the platinum source in a first solvent includes: adding the platinum source to the first solvent, then passing an inert gas into the first solvent to remove oxygen, dispersing and dissolving at room temperature to obtain a platinum source solution.

[0064] The inert gas may be selected from, but is not limited to, at least one of nitrogen and argon.

[0065] In some embodiments, the carbon support is dispersed in the platinum source solution by continuously stirring for 10 to 30 minutes.

[0066] The method for preparing the precursor solution allows for thorough mixing and uniform dispersion of the components.

[0067] In step S2:

[0068] The microwave heating includes: heating the precursor solution to a first temperature with a first microwave power, stopping the microwave heating for a period of time t1, and then heating it with a second microwave power for a period of time t2.

[0069] The first microwave power can be 1200–3000 W. Within the first microwave power range, the precursor solution can be rapidly heated to the first temperature.

[0070] The first temperature can be 130–180°C. Within this range, it is advantageous for the platinum source to nucleate at a relatively fast rate on the surface of the carbon support.

[0071] The time t1 is 5–20 min. Within this time range, it is beneficial for further growth of the crystal nucleus.

[0072] The second microwave power can be 500–1000 W, and the time t2 can be 2–10 min. Within the power and time range, it is beneficial for the platinum source in the system to continue to grow fully on the surface of the crystal nucleus, and it is also beneficial to prepare a carbon-supported platinum-based catalyst precursor with a narrow particle size distribution.

[0073] In at least one embodiment, the microwave heating is carried out in a microwave reactor.

[0074] In some embodiments, the process after microwave heating further includes cooling, washing, and drying the microwave-heated product to obtain a high-purity carbon-supported platinum-based catalyst. In some embodiments, washing involves using a detergent to wash the microwave-heated product until the conductivity of the filtrate is less than or equal to 10 μS / cm. This effectively removes impurities such as organic matter from the surface of the carbon-supported platinum-based catalyst.

[0075] The detergent may be selected from, but is not limited to, at least one of water and ethanol. In at least one embodiment, the detergent is a mixture of water and ethanol.

[0076] In step S3:

[0077] The hydrophobic agent may be selected from, but is not limited to, thiols. The thiols may be selected from, but are not limited to, at least one of n-butylthiol, n-dodecylthiol, and n-hexadecylthiol. The hydrophobic agent can impart good hydrophobicity to the prepared carbon-supported platinum-based catalyst.

[0078] The molar ratio of the carbon-supported platinum-based catalyst precursor to the hydrophobic agent is 5:(0.8–1.2). Within this ratio range, the hydrophobic agent can sufficiently and effectively hydrophobically treat the carbon-supported platinum-based catalyst to obtain a carbon-supported platinum-based catalyst with excellent hydrophobic properties.

[0079] In some embodiments, the hydrothermal reaction is carried out at a temperature of 100–200°C for a time of 10–24 hours. Within this temperature and time range, the hydrophobic agent can react fully with the carbon-supported platinum-based catalyst precursor, thereby facilitating the preparation of a carbon-supported platinum-based catalyst with excellent surface hydrophobicity.

[0080] In some embodiments, mixing the carbon-supported platinum-based catalyst precursor with a hydrophobic agent includes: dispersing the carbon-supported platinum-based catalyst precursor in a second solvent to obtain a precursor dispersion, and then adding the hydrophobic agent to the precursor dispersion.

[0081] The second solvent may be selected from, but is not limited to, at least one of water and ethanol. In at least one embodiment, the second solvent is a mixed solution of water and ethanol.

[0082] In some embodiments, the hydrothermal reaction further includes: washing the product of the hydrothermal reaction with a detergent until the conductivity of the filtrate is less than or equal to 10 μS / cm, and drying it to obtain the carbon-supported platinum-based catalyst.

[0083] The detergent is as described above.

[0084] The drying process can be one of heating drying, vacuum drying, cooling drying, and reduced pressure drying. In at least one embodiment, the drying is vacuum drying at 60–120°C for 12 hours.

[0085] The carbon-supported platinum-based catalyst prepared by the method described in this application is a Pt / C catalyst.

[0086] In some embodiments, step S1 involves providing a carbon support, a platinum source, a doped metal source, a reducing agent, and a first solvent, mixing them to obtain a precursor solution. The carbon-supported platinum-based catalyst thus prepared is a PtM / C catalyst, wherein M is a doped metal.

[0087] The doped metal source can be selected from, but is not limited to, at least one of Ru, Pd, Rh, Ir, Ni, Co, Mn, Cu, Sn, V, Ga, and Mo. The corresponding M can be selected from, but is not limited to, at least one of Ru, Pd, Rh, Ir, Ni, Co, Mn, Cu, Sn, V, Ga, and Mo.

[0088] The molar ratio of Pt in the platinum source to M in the doped metal source is Pt:M = x:y, where x > 0, y > 0, and x + y ≤ 100.

[0089] The carbon-supported platinum-based catalyst prepared by the method described in this application, i.e., the Pt / C catalyst or the PtM / C catalyst, has a metal loading of 40 to 70 wt%.

[0090] The carbon-supported platinum-based catalyst prepared by the method described in this application exhibits good surface hydrophobicity, which facilitates effective three-phase contact between O2, H2O, and the carbon-supported platinum-based catalyst. Thus, the catalyst layer of the membrane electrode assembly, including the carbon-supported platinum-based catalyst, possesses excellent water drainage capacity and high-current-density performance. Furthermore, the preparation method described in this application is simple, reproducible, and produces carbon-supported platinum-based catalyst particles with uniform size and distribution, making it suitable for large-scale industrial production.

[0091] This application also provides a carbon-supported platinum-based catalyst prepared by the above-described method for preparing carbon-supported platinum-based catalysts.

[0092] This application also provides a membrane electrode comprising an anode catalyst layer, a proton exchange membrane, and a cathode catalyst layer, wherein the anode catalyst layer and / or the cathode catalyst layer contain the carbon-supported platinum-based catalyst.

[0093] This application also provides a fuel cell including the membrane electrode. In at least one embodiment, the fuel cell is a proton exchange membrane fuel cell.

[0094] The present application will be specifically described below through specific embodiments. The following embodiments are only some embodiments of the present application and are not intended to limit the present application.

[0095] Example 1

[0096] Preparation of Pt / C catalyst:

[0097] Weigh 2.7g of H2PtCl6 into a three-necked flask, add 200mL of ethylene glycol, purge with nitrogen gas, and stir at room temperature until H2PtCl6 is completely dissolved to obtain a platinum source solution.

[0098] Add 1g of carbon black (model: XC-72) and 80g of oleylamine to the platinum source solution, and disperse by ultrasonication for 30min to obtain the precursor solution;

[0099] The precursor solution was placed in a microwave reactor, and a thermocouple was inserted into the precursor solution for temperature control. The stirring speed of the microwave reactor was adjusted to 1000 rpm, and the microwave temperature was set to 150℃. Microwave heating was performed with a first microwave power of 2500W. After the temperature reached 150℃, microwave heating was stopped for 20 minutes. Then, microwave heating was continued with a second microwave power of 800W for 5 minutes, and then microwave heating was stopped to obtain the reaction solution.

[0100] After the reaction solution cools, deionized water is added for washing, and the solution is filtered until the conductivity of the filtrate is less than 10 μS / cm. The filter cake is then placed in a forced-air drying oven at 70°C and dried for 12 hours to obtain the Pt / C catalyst precursor.

[0101] 0.5 g of Pt / C catalyst precursor and 0.1 g of n-dodecyl mercaptan were added to a mixed solvent (30 mL of water and 5 mL of ethanol), ultrasonically dispersed for 30 min, and then transferred to a 50 mL reactor. The mixture was hydrothermally reacted at 150 °C for 24 h to obtain the reaction solution.

[0102] After the reaction solution cooled, it was washed several times with water and ethanol, and then placed in a vacuum drying oven at 80°C for 12 hours to obtain the Pt / C catalyst, in which the Pt loading was 50%.

[0103] Example 2

[0104] Preparation of Pt / C catalyst:

[0105] Weigh 5g of K2PtCl6 into a three-necked flask, add 300mL of ethylene glycol, purge with nitrogen gas, and stir at room temperature until K2PtCl6 is completely dissolved to obtain a platinum source solution.

[0106] Add a mixture of 2g carbon black (model: EC600J), 70g oleylamine and 40g 1-octadecene to a platinum source solution, and ultrasonically disperse for 45min to obtain a precursor solution.

[0107] The precursor solution was placed in a microwave reactor, and a thermocouple was inserted into the precursor solution for temperature control. The stirring speed of the microwave reactor was adjusted to 800 rpm, and the microwave temperature was set to 180℃. Microwave heating was performed with a first microwave power of 1800W. After the temperature reached 180℃, the microwave was stopped for 10 minutes. Then, the microwave was continued with a second microwave power of 1000W for 10 minutes, and then the microwave was stopped to obtain the reaction solution.

[0108] After the reaction solution cools, deionized water is added for washing, and the solution is filtered until the conductivity of the filtrate is less than 10 μS / cm. The filter cake is then placed in a forced-air drying oven at 70°C and dried for 12 hours to obtain the Pt / C catalyst precursor.

[0109] 1 g of Pt / C catalyst precursor and 0.15 g of n-octyl-thiol were added to a mixed solvent (70 mL of water and 10 mL of ethanol), ultrasonically dispersed for 30 min, and then transferred to a 100 mL reactor. The mixture was hydrothermally reacted at 200 °C for 24 h to obtain the reaction solution.

[0110] After the reaction solution cooled, it was washed multiple times with water and ethanol, filtered until the conductivity of the filtrate was less than 10 μS / cm, and then placed in a vacuum drying oven at 80 °C for 12 h to obtain the Pt / C catalyst, in which the Pt loading was 60%.

[0111] Example 3

[0112] Preparation of PtCo / C catalyst:

[0113] Weigh 1.14 g of (NH4)2PtCl6 and 1.1 g of CoCl2 into a three-necked flask, add 120 mL of ethylene glycol, purge with nitrogen gas, and stir at room temperature until H2PtCl6 is completely dissolved to obtain a platinum source solution.

[0114] Add a mixture of 1g carbon nanotubes, 50g oleylamine and 70g oleic acid to a platinum source solution and disperse by ultrasonication for 50min to obtain a precursor solution;

[0115] The precursor solution was placed in a microwave reactor, and a thermocouple was inserted into the precursor solution for temperature control. The stirring speed of the microwave reactor was adjusted to 1200 rpm, and the microwave temperature was set to 170℃. Microwave heating was performed with a first microwave power of 3000W. After the temperature reached 170℃, microwave heating was stopped for 10 minutes. Then, microwave heating was continued with a second microwave power of 600W for 5 minutes. After that, microwave heating was stopped to obtain the reaction solution.

[0116] After the reaction solution cools, deionized water is added for washing, and the solution is filtered until the conductivity of the filtrate is less than 10 μS / cm. The filter cake is then placed in a forced-air drying oven at 70°C and dried for 12 hours to obtain the PtCo / C catalyst precursor.

[0117] 0.5 g of PtCo / C catalyst precursor and 0.1 g of n-dodecyl mercaptan were added to a mixed solvent (30 mL of water and 5 mL of ethanol), ultrasonically dispersed for 30 min, and then transferred to a 50 mL reactor. The mixture was hydrothermally reacted at 150 °C for 24 h to obtain the reaction solution.

[0118] After the reaction solution cooled, it was washed multiple times with water and ethanol, and then placed in a vacuum drying oven at 80°C for 12 hours to obtain the PtCo / C catalyst, wherein the loading of Pt was 20% and the loading of Co was 20%.

[0119] Comparative Example 1

[0120] Preparation of Pt / C catalyst:

[0121] Weigh 2.7g of H2PtCl6 into a three-necked flask, add 200mL of ethylene glycol, purge with nitrogen gas, and stir at room temperature until H2PtCl6 is completely dissolved to obtain a platinum source solution.

[0122] Add 1g of carbon black (model: XC-72) and 80g of oleylamine to the platinum source solution, and disperse by ultrasonication for 30min to obtain the precursor solution;

[0123] The precursor solution was placed in a microwave reactor, and a thermocouple was inserted into the precursor solution for temperature control. The stirring speed of the microwave reactor was adjusted to 1000 rpm, the microwave temperature was set to 150℃, and microwave heating was performed with a microwave power of 2500W. After the temperature reached 150℃, the microwave was stopped for 20 minutes, and then microwaved for another 5 minutes with a microwave power of 800W. The microwave was then stopped to obtain the reaction solution.

[0124] After the reaction solution cools, deionized water is added for washing, and the solution is filtered until the conductivity of the filtrate is less than 10 μS / cm. The filter cake is then placed in a forced-air drying oven at 70°C and dried for 12 hours to obtain the Pt / C catalyst.

[0125] The Pt / C catalyst of Example 1 was subjected to scanning electron microscopy (SEM) analysis, and the resulting SEM images are shown in the attached image. Figure 2 ).

[0126] Membrane electrode I, membrane electrode II, and membrane electrode III were prepared using the catalysts of Example 1, Example 2, and Comparative Example 1, respectively.

[0127] The membrane electrode is prepared as follows: Take 0.5g of catalyst and add it to a mixed solution containing 30g of isopropanol and water (V 水 V 异丙醇 A slurry was prepared by mixing a membrane solution of 7:3 and 0.2 g of perfluorosulfonic acid resin. The slurry was dispersed in an ice-water bath at 1500 rpm for 20 minutes using a high-speed shear press. Then, a 0.1 mg / cm³ coating was applied to the anode side of the proton exchange membrane using an ultrasonic sprayer. 2 The slurry was sprayed at a concentration of 0.3 mg / cm² onto the cathode side. 2 The slurry is used to obtain a three-in-one CCM (catalyst coated membrane), which is then encapsulated to obtain a membrane electrode.

[0128] Hydrophobicity tests were performed on membrane electrode I, membrane electrode II, and membrane electrode III, and the contact angles were measured. The test results are shown in Table 1 and... Figure 3 .

[0129] Table 1:

[0130] Membrane electrode I Membrane Electrode II Membrane Electrode III Contact angle 151.7° 150.3° 135.1°

[0131] From Table 1 and Figure 3 It can be seen that the hydrophobicity of membrane electrode I and membrane electrode II is significantly better than that of membrane electrode III. Therefore, the membrane electrodes prepared by the method of this application exhibit good hydrophobicity.

[0132] Polarization curves were tested for membrane electrode I and membrane electrode III. The test results are shown in the figure. Figure 4 .

[0133] The effective area of ​​membrane electrode I and membrane electrode III used in the polarization curve test was 25 cm². 2 .

[0134] The test conditions were as follows: the flow rates of hydrogen and oxygen were set to 0.5 and 2 L / min, respectively; the humidity at both the anode and cathode was set to 100% RH; the inlet pressure at both the anode and cathode was set to 100 kPa; the battery temperature and the inlet temperature at both the anode and cathode were set to 80℃; the current was applied to 50 A; and constant current activation was performed under hydrogen and oxygen conditions for approximately 30 minutes until the voltage stabilized. Subsequently, the cathode was switched to air, and the metering mode was switched to a specific ratio. The initial flow rates of the anode and cathode were set to 0.3 and 0.6 L / min, respectively, and the metering ratios of the anode and cathode were set to 1.5 and 4, respectively. After the voltage stabilized for 5 minutes, the polarization curve was tested.

[0135] Depend on Figure 4 It can be seen that the overall performance of membrane electrode I is better than that of membrane electrode III, and this difference is more pronounced in the high current density region. Therefore, the membrane electrode prepared by the method of this application has better mass transfer capability, effectively improving the liquid water discharge capacity and working performance at high current densities.

[0136] The carbon-supported platinum-based catalyst and its preparation method provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for preparing a carbon-supported platinum-based catalyst, characterized by, The application relates to a preparation method of a carbon-supported platinum-based catalyst. The carbon carrier, the platinum source, the reducing agent and the first solvent are mixed to obtain a precursor solution; The precursor solution is subjected to microwave heating to obtain a carbon-supported platinum-based catalyst precursor; The carbon-supported platinum-based catalyst precursor is mixed with a hydrophobic agent and subjected to hydrothermal reaction to obtain the carbon-supported platinum-based catalyst; the microwave heating comprises the following steps: after the precursor solution is heated to a first temperature at a first microwave power, the microwave heating is stopped for a time t1, and then the microwave heating is carried out at a second microwave power for a time t2; the first microwave power is 1200-3000 W; the first temperature is 130-180 DEG C; the time t1 is 5-20 min; the second microwave power is 500-1000 W; and the time t2 is 2-10 min; the hydrophobic agent is selected from at least one of n-butyl mercaptan, n-dodecyl mercaptan and n-hexadecyl mercaptan.

2. The production method according to claim 1, wherein The carbon carrier is selected from at least one of carbon black, carbon nanotube, graphite carbon and graphene; and / or The platinum source is selected from at least one of H2PtCl6, K2PtCl6, K2PtCl4, Na2PtCl4, (NH4)2PtCl6 and Pt (NO3)2; and / or The reducing agent is selected from at least one of oil ammonia, oleic acid, 1-octadecene, TBAB, carbonyl iron and carbonyl cobalt; and / or The first solvent is selected from at least one of ethylene glycol, isopropyl alcohol and glycerol.

3. The production method according to claim 1, wherein The average particle size of the carbon carrier is 40-200 nm.

4. The production method according to claim 1, wherein The concentration of the carbon carrier in the precursor solution is 0.004-0.012 g / mL; and / or The concentration of the platinum source in the precursor solution is 0.008-0.06 g / mL; and / or The concentration of the reducing agent in the precursor solution is 0.2-1.2 g / mL; and / or The molar ratio of the carbon-supported platinum-based catalyst precursor to the hydrophobic agent is 5: (0.8-1.2).

5. The preparation method according to claim 1, wherein The temperature of the hydrothermal reaction is 100-200 DEG C; and / or The time of the hydrothermal reaction is 10-24 h.

6. The preparation method according to claim 1, wherein After the microwave heating, the product after the microwave heating is washed until the conductivity of the filtrate is less than or equal to 10 us / cm; and / or After the hydrothermal reaction, the product after the hydrothermal reaction is washed with a detergent until the conductivity of the filtrate is less than or equal to 10 us / cm.

7. The production method according to claim 1, wherein The carbon carrier, the platinum source, the reducing agent and the first solvent further comprise a doped metal source.

8. The preparation method according to claim 7, wherein The doped metal source is selected from at least one of a Ru source, a Pd source, a Rh source, an Ir source, a Ni source, a Co source, a Mn source, a Cu source, a Sn source, a V source, a Ga source and a Mo source; and / or The molar ratio of Pt in the platinum source to M in the doped metal source is Pt:M=x:y, wherein x>0, y>0 and x+y<=100.

9. A platinum on carbon based catalyst characterized by, The carbon-supported platinum-based catalyst is prepared by the preparation method according to any one of claims 1-8.

10. The carbon-supported platinum-based catalyst of claim 9, wherein the carbon- supported platinum-based catalyst has a platinum dispersion of at least 50%. The metal loading of the carbon-supported platinum-based catalyst is 40-70 wt%.

11. A membrane electrode characterized by, The membrane electrode comprises the carbon-supported platinum-based catalyst according to any one of claims 9-10.

12. A fuel cell characterized by comprising: The fuel cell comprises the carbon-supported platinum-based catalyst according to claim 11.

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