CN116344839B

CN116344839B - High-potential catalyst and preparation method and application thereof

Info

Publication number: CN116344839B
Application number: CN202310056207.XA
Authority: CN
Inventors: 于力娜; 王晶晶; 唐柳; 刘江唯; 朱雅男; 张中天; 刘晓雪; 高梦阳; 刘阳; 马亮; 普星彤; 杨帅
Original assignee: FAW Jiefang Automotive Co Ltd
Current assignee: FAW Jiefang Automotive Co Ltd
Priority date: 2023-01-13
Filing date: 2023-01-13
Publication date: 2024-05-28
Anticipated expiration: 2043-01-13
Also published as: CN116344839A

Abstract

The invention provides a high-potential catalyst, a preparation method and application thereof, wherein the preparation method comprises the following steps: (1) Mixing a solvent, a stabilizer and sodium sulfate to obtain a mixed solution, heating, adding a palladium solution for one-step reaction, and collecting palladium seed crystals to obtain a palladium seed crystal solution; (2) Mixing palladium seed crystal solution, potassium source, stabilizer, reducer and solvent for two-step reaction to obtain reaction solution; (3) The reaction solution is mixed with the platinum source solution, the three-step reaction is carried out to obtain a composite material, the composite material is mixed with the carbon carrier solution, the dispersion treatment is carried out after the ultrasonic treatment, and the high-potential catalyst is obtained after the heat treatment.

Description

High-potential catalyst and preparation method and application thereof

Technical Field

The invention belongs to the technical field of fuel cells, and relates to a high-potential catalyst, a preparation method and application thereof.

Background

At present, the commercial vehicle heavy truck, especially 49 tons, the majority of the power of a fuel cell stack is concentrated at 150 kW-200 kW, and the power is mainly supplied to a power battery by a hydrogen fuel cell firstly and then supplied to the vehicle by the power battery, so that the fuel cell can only meet the power requirements of the heavy truck in a starting stage and a cruising stage, but cannot meet the use requirements of special conditions of acceleration, uphill and loading on power, if the heavy truck is in the working conditions of acceleration, loading, uphill and the like for a long time, the power battery is easy to lose electricity, and therefore, the development of the commercial vehicle fuel cell stack to a high-power direction is a necessary trend of industry development, the time of heavy truck load operation can be prolonged, the purchase cost of the heavy truck can be reduced, and the cargo capacity of the heavy truck can be improved.

The membrane electrode is used as a fuel cell stack as an electrochemical reaction generating place and is compared with a chip of a fuel cell, and the cost occupies more than 60% of the fuel cell stack, so that the efficiency, the service life and the cost of the membrane electrode directly determine the efficiency, the service life and the cost of the fuel cell stack. The current 49 ton heavy truck pile system has 45% efficiency, hundred kilometers hydrogen consumption of 13-15 kg, calculated by 25 yuan/kg of hydrogen, the heavy truck commercial vehicle cost of 3.25-3.5 yuan/km, and the pure electric heavy truck cost of 2.5-2.7 yuan/km, and can reach the price per kilometer comparable with that of the pure electric truck only by improving pile efficiency to 50% efficiency and the hundred kilometers hydrogen consumption of 7-10 kg. Therefore, the efficiency of the membrane electrode is further improved, and the minimum hydrogen consumption is obtained, so that the membrane electrode becomes a current research hot spot.

CN108630948a discloses a preparation method of octahedral palladium-platinum core-shell structure catalyst, firstly uniformly dispersing palladium metal particles in glycol solution, then adding glycine and chloroplatinic acid into palladium metal particle-glycol mixed liquid, and then adding deionized water; and finally, stirring and ultrasonic treatment are carried out on the mixed liquid, the solution is transferred into a reaction kettle for hydrothermal reaction, and the octahedral palladium platinum core-shell catalyst is obtained after the reaction is finished.

CN107591543a discloses a preparation method of platinum-base alloy catalyst for fuel cell, said method includes the following steps: the method comprises the steps of respectively weighing a proper amount of chloridizing handle, platinum nitrate, glycol, ethanol and polyvinylpyrrolidone, adding a proper amount of distilled water for dissolving to form a solution, and mechanically stirring the solution uniformly. Adding a proper amount of carbon black and methanol into the solution, carrying out ultrasonic stirring and mixing uniformly, heating the solution to 80-80 ℃, and then stirring at constant temperature. Filtering impurities from the stirred solution through a filter, washing, and drying to obtain the platinum-carbon catalyst.

The platinum-palladium alloy catalyst according to the above-mentioned scheme has a problem of poor high potential activity, and therefore, development of a platinum-palladium alloy catalyst having high activity and high potential activity is necessary.

Disclosure of Invention

The invention aims to provide a high-potential catalyst and a preparation method and application thereof.

In order to achieve the aim of the invention, the invention adopts the following technical scheme:

In a first aspect, the present invention provides a method for preparing a high potential catalyst, the method comprising the steps of:

(1) Mixing a solvent, a stabilizer and sodium sulfate to obtain a mixed solution, heating, adding a palladium solution for one-step reaction, and collecting palladium seed crystals to obtain a palladium seed crystal solution;

(2) Mixing palladium seed crystal solution, potassium source, stabilizer, reducer and solvent for two-step reaction to obtain reaction solution;

(3) Mixing the reaction solution with a platinum source solution, performing three-step reaction to obtain a composite material, mixing the composite material with a carbon carrier solution, performing ultrasonic treatment, performing dispersion treatment, and performing heat treatment to obtain the high-potential catalyst.

The catalyst with high activity and high stability prepared by the method can obviously improve the high potential activity of the membrane electrode, and reduce the activation polarization so that the power density of the membrane electrode is greatly improved.

Preferably, the solvent of step (1) comprises any one or a combination of at least two of diethylene glycol ether, epoxy acrylic resin, diethylene glycol butyl ether, diethylene glycol methyl ether or dipropylene glycol dimethyl ether.

Preferably, the stabilizer comprises any one or a combination of at least two of polyvinyl alcohol, polyvinylpyrrolidone, dimethyl sulfoxide, glycerol or polyethylene glycol.

Preferably, the mass ratio of the solvent, the stabilizer and the sodium sulfate is (15-50): (0.7-1.2): (0.3-0.67), for example: 15:0.7:0.3, 20:0.8:0.4, 40:1:0.5, 42:1.1:0.6, or 50:1.2:0.67, etc.

Preferably, the temperature of the heating treatment is 100 to 120 ℃, for example: 100 ℃, 105 ℃, 110 ℃, 115 ℃ or 120 ℃ and the like.

Preferably, the heating treatment is performed for 8 to 15 minutes, for example: 8min, 9min, 10min, 12min or 15min, etc.

Preferably, the solute of the palladium solution comprises any one or a combination of at least two of palladium chloride, potassium tetrachloropalladate or sodium tetrachloropalladate.

Preferably, the mass concentration of the palladium solution is 13-21 g/L, for example: 13g/L, 15g/L, 18g/L, 20g/L, 21g/L, etc.

Preferably, the temperature of the one-step reaction is 100 to 120 ℃, for example: 100 ℃, 105 ℃, 110 ℃, 115 ℃ or 120 ℃ and the like.

Preferably, the one-step reaction time is 2.5 to 5 hours, for example: 2.5h, 3h, 3.5h, 4h or 5h, etc.

Preferably, the collecting palladium seeds comprises centrifugation, washing and dispersion treatments.

Preferably, the potassium source of step (2) comprises any one or a combination of at least two of potassium bromide, potassium iodide or cetyltrimethylammonium bromide.

Preferably, the stabilizer comprises polyvinylpyrrolidone.

Preferably, the reducing agent comprises any one or a combination of at least two of ascorbic acid, glucose, sucrose or glycerol.

Preferably, the solvent comprises ethylene glycol.

Preferably, the mass ratio of the palladium seed solution, the potassium source, the stabilizer, the reducing agent and the solvent is 10 (0.48-0.71): (0.56-0.8): (1.05-1.32): (100-160), for example: 10:0.48:0.56:1.05:100, 10:0.5:0.6:1.1:110, 10:0.6:0.7:1.2:150, or 10:0.71:0.8:1.32:160, etc.

Preferably, the two-step reaction includes a primary reaction and a secondary reaction.

Preferably, the temperature of the primary reaction is 110 to 130 ℃, for example: 110 ℃, 115 ℃, 120 ℃, 125 ℃ or 130 ℃ and the like.

Preferably, the time of the one reaction is 0.5 to 2 hours, for example: 0.5h, 0.8h, 1h, 1.5h, 2h, etc.

Preferably, the temperature is raised to the temperature of the secondary reaction at a rate of 2 to 4 ℃/min (e.g., 2 ℃/min, 2.5 ℃/min, 3 ℃/min, 3.5 ℃/min, 4 ℃/min, etc.) after the primary reaction.

Preferably, the temperature of the secondary reaction is 180 to 220 ℃, for example: 180 ℃, 190 ℃, 200 ℃, 210 ℃ or 220 ℃ and the like.

Preferably, the solute of the platinum source solution in step (3) comprises any one or a combination of at least two of potassium chloroplatinate, sodium chloroplatinate, chloroplatinic acid, potassium tetrachloroplatinate, potassium hexachloroplatinate, platinum nitrate, platinum acetylacetonate, or platinum tetraaminochloride.

Preferably, the reaction solution is added dropwise to 15-24 mL of the platinum source solution at a rate of 0.08-1.0 mL/min.

Preferably, the temperature of the three-step reaction is 180 to 220 ℃, for example: 180 ℃, 190 ℃, 200 ℃, 210 ℃ or 220 ℃ and the like.

Preferably, the three-step reaction time is 1 to 2.5 hours, for example: 1h, 1.5h, 1.8h, 2h, 2.5h, etc.

Preferably, the carbon support comprises ketjen black and/or Vulcan XC72.

Preferably, the time of the ultrasonic treatment is 3 to 5 hours, for example: 3h, 3.5h, 4h, 4.5h, 5h, etc.

Preferably, the dispersion-treated stabilizer comprises acetic acid.

Preferably, the temperature of the heat treatment is 50 to 70 ℃, for example: 50 ℃, 55 ℃, 60 ℃, 65 ℃ or 70 ℃ and the like.

Preferably, the time of the heat treatment is 10 to 15 hours, for example: 10h, 11h, 12h, 13h, 14h or 15h, etc.

In a second aspect, the present invention provides a high potential catalyst prepared by the method as described in the first aspect, wherein the mass fraction of palladium is 0.1 to 4% based on 100% of the mass of the high potential catalyst, for example: 0.1%, 1%, 2%, 3% or 4%, etc.

Preferably, the mass fraction of platinum is 20-60%, for example: 20%, 30%, 40%, 50% or 60%, etc.

In a third aspect, the present invention provides a membrane electrode, the membrane electrode comprising a first gas diffusion layer, a first sealing frame, an anode catalytic layer, a proton membrane, a cathode catalytic layer, a second sealing frame and a second gas diffusion layer, which are sequentially stacked, wherein the anode catalytic layer comprises a platinum carbon catalyst and a perfluorosulfonic acid resin, and the cathode catalytic layer comprises the high-potential catalyst and the perfluorosulfonic acid resin according to the second aspect.

The invention adopts the technology of hot-pressing the proton exchange membrane with the catalyst layer and the gas diffusion layer containing the hot melt adhesive sealing frame into the membrane electrode, and has the advantages of good batch consistency and high power density.

Preferably, the size of the overlapping portion of the first sealing frame and the anode catalytic layer is 1.5 to 2.0mm, for example: 1.5mm, 1.6mm, 1.7mm, 1.8mm or 2mm, etc.

Preferably, the size of the overlapping portion of the second sealing frame and the cathode catalytic layer is 1.7-2.2 mm, for example: 1.7mm, 1.8mm, 1.9mm, 2mm or 2.2mm, etc.

Preferably, the size of the overlapping portion of the first gas diffusion layer and the first sealing frame is 1.5 to 2.5mm, for example: 1.5mm, 1.8mm, 2mm, 2.2mm or 2.5mm, etc.

Preferably, the overlapping portion of the second gas diffusion layer and the second sealing frame has a size of 1.7 to 2.7mm, for example: 1.7mm, 1.8mm, 2mm, 2.5mm, 2.7mm, etc.

Preferably, the thickness of the first gas diffusion layer is 148 to 200 μm, for example: 148 μm, 150 μm, 160 μm, 180 μm or 200 μm, etc.

Preferably, the thickness of the second gas diffusion layer is 148 to 200 μm, for example: 148 μm, 150 μm, 160 μm, 180 μm or 200 μm, etc.

In a fourth aspect, the present invention provides a method for preparing a membrane electrode according to the third aspect, the method comprising the steps of:

(1) Respectively coating the cathode catalytic layer slurry and the anode catalytic layer slurry on two sides of a proton membrane to obtain the proton membrane with an anode side and a cathode side;

(2) And sequentially arranging a sealing frame and a gas diffusion layer on the proton membrane with the anode side and the cathode side to obtain the membrane electrode.

Preferably, the cathode catalyst slurry in the step (1) comprises a high-potential catalyst, deionized water, an alcohol solvent and a Nafion ion resin solution with the mass fraction of 5-20%.

Preferably, the mass ratio of the high-potential catalyst to the deionized water to the alcohol solvent to the Nafion ion resin solution with the mass fraction of 5-20 percent is (0.0067-0.009): (0.094 to 0.225): (0.71-0.823): (0.0002-0.0012): (0.0475-0.076).

Preferably, the anode catalytic layer slurry comprises a platinum carbon catalyst, deionized water, an alcohol solvent, 5% of ionic resin by mass and an anti-reverse electrode inhibitor.

Preferably, the mass ratio of the platinum carbon catalyst, deionized water, an alcohol solvent, 5% of ionic resin and the anti-counter electrode inhibitor is (0.006-0.009): (0.15-0.196): (0.68-0.78): (0-0.35): (0-0.16): (0.06-0.096): (0.0003 to 0.0008).

Preferably, the step (2) specifically includes:

And respectively placing cut sealing frames with hot melt adhesive on two sides of a proton membrane coated with a catalyst layer, hot-pressing for 8-20 s at the temperature of 85-105 ℃ and under the pressure of 0.1-0.3 Mpa, dispensing at the position of 0.6-1.0 mm at the edge of a gas diffusion layer by using a dispensing machine, placing a first gas diffusion layer and a second gas diffusion layer on two sides of the sealing frame respectively, and pressing to obtain the membrane electrode.

Preferably, the temperature of the lamination is 70-85 ℃, for example: 70 ℃, 72 ℃, 75 ℃, 80 ℃ or 85 ℃ and the like.

Preferably, the time of the pressing is 8 to 10s, for example: 8s, 8.5s, 9s, 9.5s or 10s, etc.

Preferably, the pressure of the pressing is 0.08-0.15 Mpa, for example: 0.08Mpa, 0.1Mpa, 0.12Mpa or 0.15Mpa, etc.

In a fifth aspect, the present invention provides a fuel cell comprising a membrane electrode according to the third aspect.

Compared with the prior art, the invention has the following beneficial effects:

(1) The invention improves the high potential stability through the structural design of the catalyst; the ohmic polarization among the proton membrane, the catalytic layer and the gas diffusion layer of the membrane electrode is reduced by CCM (catalytic layer) aiming technology, so that the output current density of the membrane electrode is improved; the membrane electrode technology of hot-pressing the sealing frame, CCM and gas diffusion layer containing hot melt adhesive into a whole is adopted, and the membrane electrode technology has the advantages of good batch consistency and high power density.

(2) The high potential catalyst has mass activity up to 501mA/mgpt@0.90V, after 30000 circles of accelerated durability, up to 350.7mA/mgpt@0.90V, the mass activity attenuation is only about 30%, the initial mass activity is 1.5 times of that of the alloy catalyst in the comparative example, and the mass activity after 30000 circles is more than 3 times of that of the alloy catalyst in the comparative example.

Drawings

FIG. 1 is a graph showing the performance of the high potential catalyst of example 1 of the present invention for a 30000-cycle duration at 0.6V-1.2V.

Detailed Description

The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.

Example 1

The embodiment provides a high-potential catalyst, and the preparation method of the high-potential catalyst is as follows:

(1) Dissolving 1.5mL of diethylene glycol ether solvent, 70mg of polyvinyl alcohol and 30mg of sodium sulfate in a container, heating at 100 ℃ for 8min, dissolving 13mg of palladium chloride in 1.0mL of diethylene glycol ether, stirring for 15min, adding the uniformly stirred solution into the solution, reacting for 2.5h at 110 ℃, collecting Pd seed crystals in a centrifugal manner by a high-speed centrifuge, washing with acetone for 2 times, washing with deionized water for 3 times, washing out residual organic solvent and metal ions, and dispersing in 5mL of ethylene glycol solvent to obtain a palladium seed crystal solution;

(2) Taking 1mL of Pd seed crystal solution, mixing the Pd seed crystal solution with a container containing a mixed solution of 48mg of potassium bromide, 56mg of polyvinylpyrrolidone, 105mg of ascorbic acid and 10mL of ethylene glycol, magnetically stirring the mixture at 120 ℃ for 0.5h, and then raising the reaction temperature to 180 ℃ at 2 ℃/min to obtain a reaction solution;

(3) Slowly dripping the reaction solution into 15mL of ethylene glycol solution of potassium chloroplatinate at a rate of 0.08mL/min, reacting for 1h at 180 ℃ after dripping, centrifuging to obtain a Pd@Pt core-shell structure, loading the Pd@Pt core-shell structure onto carbon carrier Ketjen black, wherein the mass fraction of Pd and Pt is 50%, the mass fraction of Pd is 3.2%, dispersing 2.2mg of Pd@Pt and 2.2mg of carbon carrier Ketjen black into 10mL of ethanol, continuously conducting ultrasonic treatment for 4h, centrifuging to collect Pd@Pt/C core-shell catalyst, redispersing in 10mL of acetic acid, and heating at 60 ℃ for 12h to clean the surface of nanocrystals to obtain the high-potential catalyst.

Weighing 0.12g of the high-potential catalyst, adding 2mL of water for soaking, adding 55mL of isopropanol and 23mL of ethanol, stirring for 20min by ultrasonic waves, adding 1350 mu L of 5% Nafion solution, continuing ultrasonic waves for 30min, shearing and stirring for 60min under the protection of nitrogen, and crushing cells for 10min; the CCM is prepared by adopting ultrasonic spraying, the proton membrane is Goer enhanced 12 mu m, the Pt loading of the anode is 0.05mg/cm ², the cathode is 0.30mg/cm ², the carbon paper is SGL 29BC, the effective area of a membrane electrode is 5 multiplied by 10cm ², and the edge is sealed to manufacture a single cell.

The test result of the test battery is shown in fig. 1, the test result of the test battery is shown in the specification of 100KPa/110KPa, the membrane electrode prepared in the embodiment 1 has good power characteristics, the current density of 550mA/cm ²@0.8V,1800mA/cm²@0.7V,2300mA/cm² @0.65V, the current density of 0.8V can reach 550mA/cm ², the power generation efficiency can reach 65%, the power density can reach 440mA/cm ², the density of 0.7V can reach 1800mA/cm ², the power generation efficiency can reach 57%, the power density can reach 1.26W/cm ², and the invention has good hydrogen consumption efficiency under high potential on the premise of high power density and greatly reduces the use cost of a commercial vehicle if the current density is defined as a common working condition.

Example 2

(1) Dissolving 3mL of diethylene glycol ether solvent, 80mg of polyvinylpyrrolidone and 50mg of sodium sulfate in a container, heating at 110 ℃ for 10min, dissolving 15mg of potassium tetrachloropalladate in 1.0mL of ethylene glycol, stirring for 20min, adding the uniformly stirred solution into the solution, reacting for 4h at 110 ℃, collecting Pd seed crystals centrifugally by a high-speed centrifuge, washing with acetone for 2 times, washing with deionized water for 3 times, washing away residual organic solvents and metal ions, and dispersing in 7mL of ethylene glycol solvent to obtain a palladium seed crystal solution;

(2) Taking 1mL of Pd seed crystal solution, mixing the Pd seed crystal solution in a container containing 55mg of potassium iodide, 70mg of polyvinylpyrrolidone, 110mg of glucose and 12mL of ethylene glycol solution, magnetically stirring the mixture at 120 ℃ for 1.5 hours, and then increasing the reaction temperature to 200 ℃ at a speed of 3 ℃/min to obtain a reaction solution;

(3) Slowly dripping the reaction solution into 20mL of ethylene glycol solution of potassium chloroplatinate at a rate of 0.5mL/min, reacting for 2h at 200 ℃ after dripping, centrifuging to obtain a Pd@Pt core-shell structure, loading the Pd@Pt core-shell structure onto a carbon carrier Vulcan XC72, wherein the mass fraction of Pd and Pt is 40%, the mass fraction of Pd is 3%, dispersing 5mg of Pd@Pt and 7.5mg of the carbon carrier Vulcan XC72 into 14mL of ethanol, continuously conducting ultrasonic treatment for 4h, centrifuging to collect the Pd@Pt/C core-shell catalyst, redispersing in 12mL of acetic acid, and heating at 60 ℃ for 12h to clean the surface of nanocrystals to obtain the high-potential catalyst.

Example 3

(1) Dissolving 2.5mL of diethylene glycol ether solvent, 85mg of dimethyl sulfoxide and 45mg of sodium sulfate in a container, heating at 105 ℃ for 10min, dissolving 16mg of sodium tetrachloropalladate in 1.0mL of ethylene glycol, stirring for 25min, adding the uniformly stirred solution into the solution, reacting for 3.5h at 110 ℃, collecting Pd seed crystals in a centrifugal manner by a high-speed centrifuge, washing with acetone for 2 times, washing with deionized water for 3 times, washing away residual organic solvents and metal ions, and dispersing in 5mL of ethylene glycol solvent to obtain a Pd seed crystal solution;

(2) Taking 1mL of Pd seed crystal solution, mixing the Pd seed crystal solution with a container containing a mixed solution of 56mg of potassium bromide, 58mg of polyvinylpyrrolidone, 110mg of glycerol and 14mL of ethylene glycol, magnetically stirring the mixture at 120 ℃ for 0.5h, and then raising the reaction temperature to 190 ℃ at 2.5 ℃/min to obtain a reaction solution;

(3) Slowly dripping the reaction solution into 20mL of ethylene glycol solution of potassium chloroplatinate at a rate of 0.5mL/min, reacting for 2h at 200 ℃ after dripping, centrifuging to obtain a Pd@Pt core-shell structure, loading the Pd@Pt core-shell structure onto carbon carrier Ketjen black, wherein the mass fraction of Pd and Pt is 60%, the mass fraction of Pd is 3.8%, dispersing 6mg of Pd@Pt and 4mg of carbon carrier Ketjen black into 12mL of ethanol, continuously conducting ultrasonic treatment for 4h, centrifuging to collect Pd@Pt/C core-shell catalyst, redispersing in 13mL of acetic acid, and heating at 60 ℃ for 12h to clean the surface of nanocrystals to obtain the high-potential catalyst.

Example 4

(1) Dissolving 3mL of diethylene glycol ether solvent, 90mg of dimethyl sulfoxide and 60mg of sodium sulfate in a container, heating at 100 ℃ for 10min, dissolving 15mg of sodium tetrachloropalladate in 1.0mL of ethylene glycol, stirring for 25min, adding the uniformly stirred solution into the solution, reacting for 4h at 110 ℃, collecting Pd seed crystals in a centrifugal way through a high-speed centrifuge, washing with acetone for 2 times, washing with deionized water for 3 times, washing out residual organic solvent and metal ions, and dispersing in 7mL of n-butanol solvent to obtain a palladium seed crystal solution;

Comparative example 1

This comparative example differs from example 1 only in that the high potential catalyst in the cathode catalytic layer slurry was replaced with a commercial platinum alloy catalyst.

Comparative example 2

This comparative example differs from example 2 only in that the high potential catalyst in the cathode catalytic layer slurry was replaced with a commercial platinum alloy catalyst.

Comparative example 3

This comparative example differs from example 3 only in that the high potential catalyst in the cathode catalytic layer slurry was replaced with a commercial platinum alloy catalyst.

Comparative example 4

This comparative example differs from example 4 only in that the high potential catalyst in the cathode catalytic layer slurry was replaced with a commercial platinum alloy catalyst.

Initial ORR activity test: the temperature of the battery is 80 ℃, the active area is 25cm ², the anode and the cathode are respectively led into H ₂/O₂, and the flow rate An/Ca is as follows: 2/4NLPM, 50/50kPag, 2min at 0A/cm ², 15min at 1000, 200, 100, 80, 60, 40, 20mA/cm ², and 5min at 10, 6, 4, 2m A/cm ². According to the current-voltage curve (taking the mass current density as the abscissa) under the condition of H ₂/O₂, the mass specific activity (A/mg Pt@0.9V) can be obtained by taking the current value under 0.9V.

Catalyst accelerated durability test: the cell temperature was 80℃and the active area was 25cm ², and the cathode and anode were fed with 100% humidified nitrogen and hydrogen at a flow rate of 75sccm and 200sccm, respectively, with an outlet back pressure of 0kPag. The voltage is operated at 0.6-0.95V, the square wave cycle is performed, the switching time of the voltage is less than 0.5s, each cycle is 6s, and the polarization curve of the battery is tested at 30000 circles of cycles.

Catalyst support accelerated durability test: the cell temperature was 80℃and the active area was 25cm ², and the cathode and anode were fed with 100% humidified nitrogen and hydrogen at a flow rate of 75sccm and 200sccm, respectively, with an outlet back pressure of 0kPag. The operation potential is 1.0V-1.5V, and triangular wave circulation is carried out, and each circulation is 2s. The cell polarization curve was tested at 5000 cycles of integration.

The catalysts obtained in examples 1-4, comparative examples 1-4 and commercial platinum carbon catalysts were tested for mass activity on single cells with a cell active area of 25cm ² and a total Pt loading of 0.35mg/cm ².

TABLE 1

As can be seen from Table 1, the mass activity of the high potential catalyst of the present invention can be up to 501mA/mgpt@0.90V or more, the mass activity after 30000 cycles of accelerated durability can be up to 350.7mA/mgpt@0.90V or more, the mass activity decay is only about 30%, the initial mass activity is about 2 times that of the alloy catalyst of the comparative example, and the mass activity after 30000 cycles is about 3 times that of the alloy catalyst of the comparative example, as can be seen from the comparison of examples 1 to 4 and comparative examples 1 to 4.

The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.

Claims

1. A method for preparing a high potential catalyst for use in a fuel cell for a heavy truck of a commercial vehicle, the method comprising the steps of:

The solvent comprises any one or a combination of at least two of diethylene glycol ether, epoxy acrylic resin, diethylene glycol butyl ether, diethylene glycol methyl ether or dipropylene glycol dimethyl ether;

The mass ratio of the solvent to the stabilizer to the sodium sulfate is (15-50): 0.7-1.2): 0.3-0.67;

2. The method of claim 1, wherein the stabilizer of step (1) comprises any one or a combination of at least two of polyvinyl alcohol, polyvinylpyrrolidone, dimethyl sulfoxide, glycerol, or polyethylene glycol.

3. The method according to claim 1, wherein the temperature of the heating treatment in the step (1) is 100 to 120 ℃.

4. The method of claim 1, wherein the heating treatment in step (1) is performed for 8 to 15 minutes.

5. The method of claim 1, wherein the solute of the palladium solution of step (1) comprises any one or a combination of at least two of palladium chloride, potassium tetrachloropalladate, or sodium tetrachloropalladate.

6. The preparation method of claim 1, wherein the mass concentration of the palladium solution in the step (1) is 13-21 g/L.

7. The method of claim 1, wherein the temperature of the one-step reaction in step (1) is 100 to 120 ℃.

8. The method of claim 1, wherein the one-step reaction in step (1) is performed for 2.5 to 5 hours.

9. The method of claim 1, wherein collecting palladium seeds in step (1) comprises centrifugation, washing, and dispersion.

10. The method of claim 1, wherein the potassium source of step (2) comprises any one or a combination of at least two of potassium bromide, potassium iodide, or cetyltrimethylammonium bromide.

11. The method of claim 1, wherein the stabilizer of step (2) comprises polyvinylpyrrolidone.

12. The method of claim 1, wherein the reducing agent of step (2) comprises any one or a combination of at least two of ascorbic acid, glucose, sucrose, or glycerol.

13. The method of claim 1, wherein the solvent of step (2) comprises ethylene glycol.

14. The method according to claim 1, wherein the mass ratio of the palladium seed solution, the potassium source, the stabilizer, the carbon source and the solvent in the step (2) is 10 (0.48-0.71): 0.56-0.8): 1.05-1.32): 100-160.

15. The method of claim 1, wherein the two-step reaction of step (2) comprises a primary reaction and a secondary reaction.

16. The method of claim 15, wherein the temperature of the first reaction is 110-130 ℃.

17. The method of claim 15, wherein the time of the one reaction is 0.5 to 2 hours.

18. The method according to claim 15, wherein the temperature is raised to the temperature of the secondary reaction at a rate of 2 to 4 ℃/min after the primary reaction.

19. The method of claim 15, wherein the secondary reaction is carried out at a temperature of 180-220 ℃.

20. The method of claim 1, wherein the solute of the platinum source solution of step (3) comprises any one or a combination of at least two of potassium chloroplatinate, sodium chloroplatinate, chloroplatinic acid, potassium tetrachloroplatinate, potassium hexachloroplatinate, platinum nitrate, platinum acetylacetonate, or platinum tetramminochloride.

21. The method according to claim 1, wherein the reaction solution in step (3) is added dropwise to 15 to 24mL of the platinum source solution at a rate of 0.08 to 1.0 mL/min.

22. The method of claim 1, wherein the temperature of the three-step reaction in step (3) is 180-220 ℃.

23. The preparation method of claim 1, wherein the three-step reaction in the step (3) is performed for 1 to 2.5 hours.

24. The method of claim 1, wherein the carbon support of step (3) comprises ketjen black and/or Vulcan XC72.

25. The method of claim 1, wherein the time of the ultrasonic treatment in step (3) is 3 to 5 hours.

26. The method of claim 1, wherein the dispersion-treated stabilizer of step (3) comprises acetic acid.

27. The method according to claim 1, wherein the temperature of the heat treatment in the step (3) is 50 to 70 ℃.

28. The method of claim 1, wherein the heat treatment in step (3) is performed for 10 to 15 hours.

29. A high-potential catalyst, characterized in that the high-potential catalyst is produced by the method according to any one of claims 1 to 28, and the mass fraction of palladium is 0.1 to 4% based on 100% of the mass of the high-potential catalyst.

30. The high potential catalyst of claim 29, wherein the mass fraction of platinum is 20-60%.

31. A membrane electrode, wherein the membrane electrode comprises a first gas diffusion layer, a first sealing frame, an anode catalytic layer, a proton membrane, a cathode catalytic layer, a second sealing frame and a second gas diffusion layer which are sequentially stacked, the anode catalytic layer comprises a platinum carbon catalyst and perfluorinated sulfonic acid resin, and the cathode catalytic layer comprises the high-potential catalyst and perfluorinated sulfonic acid resin according to claim 29.

32. The membrane electrode according to claim 31, wherein the overlapping portion of the first sealing frame and the anode catalytic layer has a size of 1.5 to 2.0mm.

33. The membrane electrode according to claim 31, wherein the overlapping portion of the second sealing frame and the cathode catalytic layer has a size of 1.7 to 2.2mm.

34. The membrane electrode of claim 31, wherein the overlapping portion of the first gas diffusion layer and the first sealing frame has a size of 1.5mm to 2.5mm.

35. The membrane electrode according to claim 31, wherein the overlapping portion of the second gas diffusion layer and the second sealing frame has a size of 1.7 to 2.7mm.

36. The membrane electrode of claim 31, wherein the first gas diffusion layer has a thickness of 148 μm to 200 μm.

37. The membrane electrode of claim 31, wherein the second gas diffusion layer has a thickness of 148 μm to 200 μm.

38. A method of preparing the membrane electrode of claim 31, comprising the steps of:

39. The method of claim 38, wherein the cathode catalyst slurry of step (1) comprises a high potential catalyst, deionized water, an alcohol solvent, and a Nafion ion resin solution with a mass fraction of 5-20%.

40. The method according to claim 39, wherein the mass ratio of the high-potential catalyst, deionized water, alcohol solvent and Nafion ion resin solution with the mass fraction of 5-20% is (0.0067-0.009): (0.094 to 0.225): (0.71 to 0.823): (0.0002 to 0.0012): (0.0475-0.076).

41. The method of claim 38, wherein the anode catalytic layer slurry comprises a platinum carbon catalyst, deionized water, an alcohol solvent, 5% by mass of an ionic resin, and an anti-reverse inhibitor.

42. The method according to claim 41, wherein the mass ratio of the platinum-carbon catalyst, deionized water, alcohol solvent, ion resin with mass fraction of 5% and anti-counter electrode inhibitor is (0.006-0.009): (0.15-0.196): (0.68-0.78): (0-0.35): (0-0.16): (0.06-0.096): (0.0003 to 0.0008).

43. The method of claim 38, wherein step (2) specifically comprises:

And respectively placing cut sealing frames with hot melt adhesive on two sides of a proton membrane coated with a catalyst layer, hot-pressing for 8-20 s at the temperature of 85-105 ℃ and under the pressure of 0.1-0.3 mpa, dispensing at the position of 0.6-1.0 mm at the edge of a gas diffusion layer by using a dispensing machine, wherein the width of an adhesive tape is 0.6-0.8 mm, respectively placing a first gas diffusion layer and a second gas diffusion layer on two sides of the sealing frame, and pressing to obtain the membrane electrode.

44. The method of claim 43, wherein the temperature of the pressing is 70-85 ℃.

45. The method of claim 43, wherein the pressing time is 8-10 s.

46. The method of claim 43, wherein the pressure of the pressing is 0.08-0.15 MPa.

47. A fuel cell comprising the membrane electrode of claim 31.