Anode composite catalyst layer and slurry thereof, preparation method, and membrane electrode

Abstract

Disclosed in the present application are an anode composite catalyst layer and a slurry thereof, a preparation method, and a membrane electrode. The anode composite catalyst layer is located between a proton exchange membrane and a gas diffusion layer of the membrane electrode, and comprises: an iridium catalyst layer, which has a first surface and a second surface which are opposite to each other, wherein the first surface faces the proton exchange membrane, and the second surface faces the gas diffusion layer, and the iridium catalyst layer comprises a first ionomer and an iridium catalyst dispersed in the first ionomer; and a platinum-conducting layer, which has a third surface and a fourth surface which are opposite to each other, wherein the third surface is in contact with the second surface of the iridium catalyst layer, and the fourth surface faces the gas diffusion layer, and the platinum-conducting layer comprises a second ionomer and platinum nano-particles which are dispersed in the second ionomer and have a particle size of 10-500 nm. The anode composite catalyst layer of the present application can endow the membrane electrode with a relatively low contact resistance and excellent stability.

Description

Anode composite catalyst layer, slurry thereof, preparation method and membrane electrode TECHNICAL FIELD

[0001] The present application relates to the technical field of proton exchange membrane electrolysis water membrane electrode, and particularly relates to an anode composite catalyst layer, a slurry thereof, a preparation method and a membrane electrode. BACKGROUND

[0002] A membrane electrode assembly (MEA), also referred to as a membrane electrode, mainly comprises a proton exchange membrane (PEM), a catalyst layer (CL) and a gas diffusion layer (GDL). The catalyst layer is a place where electrochemical reactions take place, which can significantly reduce the activation energy required for the reaction, thereby accelerating the rate of electrochemical reactions.

[0003] The catalyst layer of the membrane electrode assembly comprises an anode catalyst layer and a cathode catalyst layer, wherein the anode catalyst layer can promote the oxidation reaction (HOR) of hydrogen, and the cathode catalyst layer can promote the reduction reaction (ORR) of oxygen, both of which have a great influence on the performance of the membrane electrode.

[0004] Since the performance of the current membrane electrode still needs to be improved, it is still necessary to continue to improve the catalyst layer.

[0005] SUMMARY

[0006] The present application aims to provide an anode composite catalyst layer, a slurry thereof, a preparation method and a membrane electrode, so that the membrane electrode has both low contact resistance and excellent stability.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0008] In a first aspect, the present application provides an anode composite catalyst layer located between a proton exchange membrane and a gas diffusion layer of a membrane electrode, comprising: an iridium catalyst layer having opposite first and second surfaces, wherein the first surface faces the proton exchange membrane, and the second surface faces the gas diffusion layer, the iridium catalyst layer comprising a first ionomer and an iridium catalyst dispersed in the first ionomer; a platinum conductive layer having opposite third and fourth surfaces, wherein the third surface is in contact with the second surface of the iridium catalyst layer, and the fourth surface faces the gas diffusion layer, and the platinum conductive layer comprises a second ionomer and platinum nanoparticles with a particle size of 10-500 nm dispersed in the second ionomer.

[0009] In some embodiments of the first aspect, the platinum nanoparticles have a particle size of 90 nm to 120 nm; the platinum conductive layer has a thickness of 0.3 μm to 1.5 μm; and the mass ratio of the platinum nanoparticles to the second ionomer is 1:(0.35 to 0.9).

[0010] In some embodiments of the first aspect, the first ionomer and the second ionomer each comprise one or more of Nafion D2020, Nafion NR50, Aquivion D79-25B, and HCD-1820.

[0011] In some embodiments of the first aspect, the iridium catalyst is at least one of IrO2, IrRuO x1 , IrO2 / TiO2, IrO2 / NbO x1 , IrO2 / Ta2O5, IrO2 / WO x1 , or IrO2 / Nb2O 5-x2 , wherein x1 is 1 to 2 and x2 is 0 to 3.

[0012] In the second aspect, the present application provides an anode composite catalyst layer slurry, comprising: an iridium catalyst layer slurry, the iridium catalyst layer slurry comprising: an iridium catalyst, a first ionomer, and a first solvent; and a platinum conductive layer slurry, the platinum conductive layer slurry comprising platinum nanoparticles having a particle size of 10 nm to 500 nm, a second ionomer, and a second solvent.

[0013] In some embodiments of the second aspect, the mass ratio of the iridium catalyst, the first ionomer, and the first solvent is 1:(0.1 to 0.5):(5 to 50); and the mass ratio of the platinum nanoparticles, the second ionomer, and the second solvent is 1:(0.35 to 0.9):(10 to 50).

[0014] In some embodiments of the second aspect, the first ionomer and the second ionomer each comprise one or more of Nafion D2020, Nafion NR50, Aquivion D79-25B, and HCD-1820; the iridium catalyst is at least one of IrO2, IrRuO x , IrO2 / TiO2, IrO2 / NbO x , IrO2 / Ta2O5, IrO2 / WO x , or IrO2 / Nb2O 5-x ; and the first solvent and the second solvent are the same or different and are selected from at least one of isopropyl alcohol, ethylene glycol, ethanol, n-propanol, and water.

[0015] In a third aspect, the application provides a preparation method of the anode composite catalyst layer, which is prepared by using the anode composite catalyst layer slurry.

[0016] In some embodiments of the third aspect, the preparation method comprises: forming an iridium catalyst layer on the surface of the proton exchange membrane of the membrane electrode by using the iridium catalyst layer slurry and by coating or transferring; forming a platinum conductive layer on the surface of the iridium catalyst layer by using the platinum conductive layer slurry and by coating or transferring; or, the preparation method comprises: forming a platinum conductive layer on the transfer material by using the platinum conductive layer slurry and by coating or transferring; forming an iridium catalyst layer on the surface of the platinum conductive layer by using the iridium catalyst layer slurry and by coating; and transferring the laminated structure of the platinum conductive layer and the iridium catalyst layer to the surface of the proton exchange membrane by transferring and removing the transfer material.

[0017] In a fourth aspect, the application provides a membrane electrode, which comprises a proton exchange membrane, a gas diffusion layer and the anode composite catalyst layer.

[0018] Compared with the prior art, the technical scheme of the application has the following beneficial effects:

[0019] The platinum conductive layer provided between the iridium catalyst layer and the gas diffusion layer can significantly reduce the contact resistance between the iridium catalyst layer and the gas diffusion layer, and can also reduce the thermal stress of the membrane electrode, thereby improving the stability of the membrane electrode. By controlling the particle size of the platinum nanoparticles in the platinum conductive layer, the contact resistance and the stability of the membrane electrode can be further balanced. BRIEF DESCRIPTION OF DRAWINGS

[0020] The following drawings describe the exemplary embodiments disclosed in the application in detail. The same reference signs in the drawings represent similar structures in several views of the drawings. Those skilled in the art will understand that these embodiments are non-limiting, exemplary embodiments, and the drawings are only for the purpose of illustration and description, and are not intended to limit the scope of the application, and other embodiments can also achieve the same purpose of the application. It should be understood that the drawings are not drawn to scale. Among them:

[0021] Fig. 1 is an exploded schematic view of a membrane electrode according to an embodiment of the application;

[0022] Fig. 2 is a flowchart of a preparation method of an anode composite catalyst layer according to an embodiment of the application;

[0023] Fig. 3 is a flowchart of a preparation method of an anode composite catalyst layer according to another embodiment of the application;

[0024] Fig. 4 is an XRD pattern of a platinum conductive layer prepared in Example 1 of the application;

[0025] FIG. 5 is a TEM image of a platinum conductive layer prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0026] The following description provides specific applications and requirements of the present application, which is intended to enable a person skilled in the art to manufacture and use the contents of the present application. Various local modifications to the disclosed embodiments are apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of the present application. Therefore, the present application is not limited to the embodiments shown, but is consistent with the widest scope of the claims.

[0027] Referring to FIG. 1, the anode composite catalyst layer 100 provided by the present application is located between the proton exchange membrane 200 and the gas diffusion layer 300 of the membrane electrode 10, and includes: an iridium catalyst layer 110 and a platinum conductive layer 120, the iridium catalyst layer 110 having opposite first and second surfaces 111 and 112, wherein the first surface 111 faces the proton exchange membrane 200, and the second surface 112 faces the gas diffusion layer 300, the iridium catalyst layer 110 including a first ionomer and an iridium catalyst dispersed in the first ionomer. The iridium catalyst layer 110 is used to promote the oxidation reaction of hydrogen.

[0028] The platinum conductive layer 120 has opposite third and fourth surfaces 121 and 122, wherein the third surface 121 is in contact with the second surface 112 of the iridium catalyst layer 110, and the fourth surface 122 faces the gas diffusion layer 300, the platinum conductive layer 120 including a second ionomer and platinum nanoparticles dispersed in the second ionomer. The platinum conductive layer 120 can significantly reduce the contact resistance between the iridium catalyst layer 110 and the gas diffusion layer 300, so that electrons can quickly flow from the iridium catalyst layer 110 to the gas diffusion layer 300, thereby improving the current density of the proton exchange membrane water electrolysis membrane electrode. At the same time, the platinum conductive layer 120 can also optimize the interface structure between the iridium catalyst layer 110 and the gas diffusion layer 300, thereby enhancing the gas diffusion effect, which helps to reduce the polarization phenomenon in the anode reaction process, so that more oxygen generated by the reaction can quickly diffuse into the flow field. Therefore, the introduction of the platinum conductive layer 120 can effectively improve the performance of the proton exchange membrane water electrolysis membrane electrode.

[0029] The introduction of the platinum conductive layer 120 also helps to improve the stability and durability of the proton exchange membrane water electrolysis membrane electrode. Since platinum has good corrosion resistance and chemical stability, not only can it maintain stable performance in the harsh working environment of the proton exchange membrane water electrolysis membrane electrode, but it can also protect the iridium catalyst layer 110 from corrosion by electrolytes or other corrosive substances, helping to extend the service life of the anode composite catalyst layer 100. In addition, since the platinum conductive layer 120 can reduce the contact resistance, it can solve the problem of excessive heat accumulation due to excessive contact resistance, thereby slowing down the thermal aging process of the proton exchange membrane water electrolysis membrane electrode.

[0030] In addition to reducing contact resistance, the platinum conductive layer 120 can also have a synergistic catalytic effect with the iridium catalyst layer 110, making the catalytic activity of the anode composite catalyst layer 100 higher than that of a single catalyst layer. At the same time, the platinum conductive layer 120 covers the iridium catalyst layer 110, which can further increase the number of active sites of the catalyst. These active sites can more effectively adsorb and convert reactants, thereby increasing the catalytic reaction rate.

[0031] The particle size of the platinum nanoparticles in the platinum conductive layer 120 has a significant impact on the contact resistance and stability of the membrane electrode. If the particle size of the platinum nanoparticles is too large, it will result in high contact resistance, hindering the transmission of electrons and thus reducing the performance of the proton exchange membrane water electrolysis membrane electrode. When the particle size of the platinum nanoparticles is too small, the specific surface area of the particles is high, and therefore the surface energy is also high, making the nanoparticles prone to aggregation, sedimentation, or dissolution, and other unstable phenomena. The present inventors have found that when the particle size of the platinum nanoparticles is 10-500 nm, the contact resistance and stability of the membrane electrode can be better balanced.

[0032] In some preferred embodiments, the particle size of the platinum nanoparticles is 90-120 nm. More preferably, the particle size of the platinum nanoparticles is 95-110 nm. Most preferably, the particle size of the platinum nanoparticles is 100 nm, which can achieve the best contact resistance and stability of the membrane electrode.

[0033] The thickness of the platinum conductive layer 120 also affects the contact resistance and stability of the membrane electrode. As the thickness of the platinum conductive layer 120 increases, the path of the reaction gas from the gas diffusion layer to the surface of the catalyst layer is prolonged, increasing the mass transfer resistance, which slows down the diffusion rate of the reaction gas in the catalyst layer, affecting the rate and efficiency of the electrochemical reaction. At the same time, the increase in the thickness of the platinum conductive layer 120 also increases the contact resistance, reduces the current density of the battery, and increases the generation and accumulation of heat, which is not conducive to the stability and high-pressure durability of the membrane electrode. In addition, when the platinum conductive layer 120 is too thick, it will affect the transport and distribution of water, which may cause flooding or drying in the membrane electrode, thereby affecting the performance and life of the battery. In some preferred embodiments, the thickness of the platinum conductive layer is 1.5 μm to 1.8 μm. Preferably, the thickness of the platinum conductive layer is 0.50 μm to 0.70 μm.

[0034] The mass ratio of the platinum nanoparticles and the second ionomer affects the electrical conductivity and ion conductivity. In some preferred embodiments, the mass ratio of the platinum nanoparticles and the second ionomer is 1:(0.35-0.9). Preferably, the mass ratio of the platinum nanoparticles and the second ionomer is 1:(0.35-0.5).

[0035] In some preferred embodiments, the first ionomer and the second ionomer each comprise a perfluorosulfonic acid resin. Further preferably, the first ionomer and the second ionomer each comprise one or more of Nafion D2020, Nafion NR50, Aquivion D79-25B, and HCD-1820. More preferably, the first ionomer and the second ionomer each comprise Nafion D2020.

[0036] In some preferred embodiments, the iridium catalyst is at least one of IrO2, IrRuO x1 , IrO2 / TiO2, IrO2 / NbO x1 , IrO2 / Ta2O5, IrO2 / WO x1 , or IrO2 / Nb2O 5-x2 , wherein x1 is 1-2 and x2 is 0-3.

[0037] The application also provides an anode composite catalyst layer slurry, comprising: an iridium catalyst layer slurry and a platinum conductive layer slurry, wherein the iridium catalyst layer slurry comprises: an iridium catalyst, a first ionomer, and a first solvent; and the platinum conductive layer slurry comprises platinum nanoparticles with a particle size of 10-500 nm, a second ionomer, and a second solvent.

[0038] In some preferred embodiments, the mass ratio of the iridium catalyst, the first ionomer and the first solvent is 1:(0.1-0.5):(5-50); the mass ratio of the platinum nanoparticles, the second ionomer and the second solvent is 1:(0.35-0.9):(10-50).

[0039] In some preferred embodiments, the mass ratio of the platinum nanoparticles, the second ionomer and the second solvent is 1:(0.35-0.9):(10-50). More preferably, the ratio is 1:(0.35-0.5):(10-50). Even more preferably, the ratio is 1:(0.35-0.5):10.

[0040] In some preferred embodiments, the first ionomer and the second ionomer each comprise a perfluorosulfonic acid resin. Further preferably, the first ionomer and the second ionomer each comprise one or more of Nafion D2020, Nafion NR50, Aquivion D79-25B, HCD-1820. More preferably, the first ionomer and the second ionomer each comprise Nafion D2020.

[0041] In some preferred embodiments, the iridium catalyst is at least one of IrO2, IrRuO x1 , IrO2 / TiO2, IrO2 / NbO x1 , IrO2 / Ta2O5, IrO2 / WO x1 or IrO2 / Nb2O 5-x2 , wherein x1 is 1-2 and x2 is 0-3.

[0042] In some preferred embodiments, the first solvent and the second solvent are the same or different and are selected from at least one of isopropyl alcohol, ethylene glycol, ethanol, n-propanol and water.

[0043] In some preferred embodiments, the solid content of the iridium catalyst layer slurry and the platinum conductive layer slurry is 6wt%-15wt%.

[0044] The present application also provides a preparation method of an anode composite catalyst layer, which is prepared using the anode composite catalyst layer slurry described above.

[0045] Referring to FIG. 2, in some embodiments, the preparation method of the anode composite catalyst layer comprises the following steps:

[0046] S1: using an iridium catalyst layer slurry and forming an iridium catalyst layer on the surface of the proton exchange membrane of the membrane electrode by a coating method or a transfer printing method;

[0047] S2: Forming a platinum conductive layer on the surface of the iridium catalyst layer by using a platinum conductive layer slurry and a coating method or a transfer method.

[0048] Referring to FIG. 3, in some embodiments, the preparation method of the anode composite catalyst layer comprises the following steps:

[0049] S10: Forming a platinum conductive layer on the transfer material by using a platinum conductive layer slurry and a coating method or a transfer method;

[0050] S20: Forming an iridium catalyst layer on the surface of the platinum conductive layer by using an iridium catalyst layer slurry and a coating method;

[0051] S30: Transferring the stack structure of the platinum conductive layer and the iridium catalyst layer to the surface of a proton exchange membrane by a transfer method, and removing the transfer material.

[0052] The steps of forming a film layer by the coating method and the transfer method described above are performed in a known manner.

[0053] The present application also provides a membrane electrode comprising a proton exchange membrane, a gas diffusion layer, and the anode composite catalyst layer described above. The proton exchange membrane and the gas diffusion layer can adopt any existing structure or material.

[0054] In some specific embodiments, the gas diffusion layer is a titanium porous diffusion layer.

[0055] In some specific embodiments, the proton exchange membrane is a perfluorosulfonic acid-based proton membrane.

[0056] In some specific embodiments, the membrane electrode further comprises other common film layer structures, such as a cathode catalyst layer adjacent to the proton exchange membrane.

[0057] The technical solutions of the present application will be described clearly and completely in combination with the embodiments of the present application. Unless otherwise specified, the reagents and raw materials used can be purchased through commercial channels. The experimental methods not specified in the following examples are selected according to conventional methods and conditions, or according to the product instructions.

[0058] Iridium oxide particles were purchased from Heraeus Company, model H2EL-IrO; platinum nanoparticles were purchased from Johnson Matthey Company, model HISPEC1000; Nafion D2020 was purchased from DuPont Company.

[0059] Example 1

[0060] The embodiment provides an anode composite catalyst layer and a preparation method thereof, the anode composite catalyst layer comprises an iridium catalyst layer and a platinum conductive layer, the iridium catalyst layer comprises Nafion D2020 and iridium oxide particles dispersed in the Nafion D2020, and the platinum conductive layer comprises Nafion D2020 and platinum nanoparticles with a particle size of 100 nm dispersed in the Nafion D2020.

[0061] The preparation method of the anode composite catalyst layer comprises the following steps:

[0062] (1) 2g of platinum nanoparticles with a particle size of 100 nm, 1g of Nafion D2020, 15g of isopropyl alcohol and 5g of deionized water are uniformly mixed to obtain a platinum conductive layer slurry; 2g of iridium oxide particles, 1g of Nafion D2020, 5g of isopropyl alcohol and 5g of deionized water are uniformly mixed to obtain an iridium catalyst layer slurry.

[0063] (2) The platinum conductive layer slurry is coated on a PTFE substrate by using a coating machine, and after drying, a platinum conductive layer with a thickness of 0.50-0.70 μm is obtained.

[0064] (3) The iridium catalyst layer slurry is coated on the surface of the platinum conductive layer by using a coating machine, and after drying, an iridium catalyst layer with a thickness of 5.0-5.3 μm is obtained.

[0065] Embodiment 2

[0066] Compared with embodiment 1, the difference of the anode composite catalyst layer and the preparation method thereof in the embodiment lies in that the particle size of the platinum nanoparticles is 10 nm.

[0067] Embodiment 3

[0068] Compared with embodiment 1, the difference of the anode composite catalyst layer and the preparation method thereof in the embodiment lies in that the particle size of the platinum nanoparticles is 50 nm.

[0069] Embodiment 4

[0070] Compared with embodiment 1, the difference of the anode composite catalyst layer and the preparation method thereof in the embodiment lies in that the particle size of the platinum nanoparticles is 200 nm.

[0071] Embodiment 5

[0072] Compared with embodiment 1, the difference of the anode composite catalyst layer and the preparation method thereof in the embodiment lies in that the particle size of the platinum nanoparticles is 500 nm.

[0073] Embodiment 6

[0074] The anode composite catalyst layer and the preparation method thereof of the present example differ from those of Example 1 only in that the thickness of the platinum conductive layer is 1 μm to 1.5 μm.

[0075] Comparative Example 1

[0076] The anode composite catalyst layer and the preparation method thereof of the present comparative example differ from those of Example 1 only in that the particle size of the platinum nanoparticles is 5 nm.

[0077] Comparative Example 2

[0078] The anode composite catalyst layer and the preparation method thereof of the present comparative example differ from those of Example 1 only in that the particle size of the platinum nanoparticles is 550 nm.

[0079] Comparative Example 3

[0080] The anode composite catalyst layer and the preparation method thereof of the present comparative example differ from those of Example 1 only in that the mass ratio of the platinum nanoparticles and Nafion D2020 is 1:0.33.

[0081] Comparative Example 4

[0082] The anode composite catalyst layer and the preparation method thereof of the present comparative example differ from those of Example 1 only in that the mass ratio of the platinum nanoparticles and Nafion D2020 is 1:1.

[0083] Comparative Example 5

[0084] The anode composite catalyst layer and the preparation method thereof of the present comparative example differ from those of Example 1 only in that the thickness of the platinum conductive layer is 0.1 μm to 0.2 μm.

[0085] Comparative Example 6

[0086] The present comparative example provides an anode catalyst layer and a preparation method thereof, the anode catalyst layer comprising Nafion D2020 and iridium oxide particles dispersed in the Nafion D2020.

[0087] The preparation method of the anode catalyst layer comprises the following steps:

[0088] (1) 2 g of iridium oxide particles, 1 g of Nafion D2020, 5 g of isopropyl alcohol and 5 g of deionized water are uniformly mixed to obtain an anode catalyst layer slurry.

[0089] (2) The anode catalyst layer slurry is coated on the surface of a perfluorosulfonic acid proton membrane using a coating machine, and an anode catalyst layer is obtained after drying.

[0090] Performance characterization:

[0091] 1) The platinum conductive layer prepared in Example 1 was subjected to XRD test by using X-ray diffractometer (Rigaku D / max-2500B2+ / PC), the scanning range was 10°-90°, and the angle increment was 0.03° / second. The test results are shown in Figure 4. As shown in Figure 4, the lattice of the sample corresponds to the standard card results of platinum, and the average particle size D of the platinum black particles was calculated to be 102 nm according to the following Sherrer equation. D=Kλ / (βcosθ);

[0092] In the above formula, K is a constant; λ is the X-ray wavelength; β is the half-height width of the diffraction peak; and θ is the diffraction angle. In the above formula, the value of the constant K is related to the definition of β. When β is the half-height width, K is 0.89; and when β is the integral width, K is 1.0.

[0093] 2) The platinum conductive layer prepared in Example 1 was subjected to TEM test by using FEI TECNAI G2 F20 200KV field emission transmission electron microscope, and the acceleration voltage was 200KV. The test results are shown in Figure 5. In Figure 5, the film layer in the red box is the platinum conductive layer, and the film layer between the red arrows is the iridium catalyst layer. The thickness of the platinum conductive layer is 0.50-0.70 μm, and the dispersion between the platinum nanoparticles is good without agglomeration phenomenon.

[0094] Contact resistance test: The contact resistance test was carried out according to the standard GB / T 20042.6-2011.

[0095] Stability test:

[0096] The stack structure of the platinum conductive layer and the iridium catalyst layer obtained from Examples 1-6 and Comparative Examples 1-6 was transferred to the surface of a perfluorosulfonic acid matrix proton membrane by transfer printing, and the PTFE substrate was removed to obtain a membrane electrode, and the test was carried out after assembling a gas diffusion layer.

[0097] After the obtained membrane electrode was subjected to voltage cycle (1.45V(3min) / 2.0V(3min)) for 10000 cycles, the current density was 2A / cm 2 The corresponding voltage, and the test results are shown in Table 1.

[0098] Table 1: Contact resistance and stability test results

[0099] From Table 1, it can be seen that, although Comparative Example 1 and Comparative Example 3 have a low contact resistance comparable to the examples of the present application, the voltage loss value is much higher than that of the examples of the present application. Although the voltage loss values of Comparative Example 2, Comparative Example 4 to Comparative Example 6 are relatively small, their contact resistance values are relatively high. Therefore, compared with Comparative Example 1 to Comparative Example 6, the membrane electrode prepared by using the anode composite catalyst layer of Example 1 to Example 6 can have both low contact resistance and excellent stability.

[0100] Membrane electrode performance test

[0101] The membrane electrode prepared above was tested by using an electrolytic water test bench, and the specific test method is as follows:

[0102] 1) Prepare the test environment (water quality resistivity is greater than 3 MΩ / cm), and ensure that the water gas pipeline is correctly built and the temperature control system can work normally;

[0103] 2) Assemble the electrolytic water clamp, and place the electrolytic water clamp on the desktop, and assemble from bottom to top as follows: cathode end plate → cathode gold-plated plate → graphite plate → cathode gasket → carbon paper → membrane electrode → anode gasket → sintered titanium plate → anode flow channel plate → anode end plate. After placing each part, use a torque wrench to tighten the screws in the fixed order with a torque of 2 → 3 → 4 → 5 Nm per turn. Then install the electrolytic water clamp on the test bench.

[0104] 3) Install the DC power load line and SENSE line, open the flowmeter so that the upper end of the float is close to the 100 mL / min scale line. Press the heating button. Wait for the clamp temperature to rise to the set temperature of 80℃, and start the test.

[0105] 4) Adjust the test program (increase 0.2 A / cm 2 , stay for four minutes in each stage) to perform polarization curve test.

[0106] Table 2 shows the voltage values at different current densities. The results show that, compared with Comparative Example 2, Comparative Example 4 and Comparative Example 6, the membrane electrode prepared by using the anode composite catalyst layer of Example 1 to Example 6 has a lower voltage value when applied to electrolytic water at the same current density. Therefore, the anode composite catalyst layer prepared in the examples of the present application has better catalytic effect.

[0107] Table 2 membrane electrode performance test results

[0108] The above description of the embodiments is given for the purpose of completeness to provide one of ordinary skill in the art with a thorough understanding of the application and does not limit the application to any one embodiment or application. It will be apparent to those skilled in the art that various modifications and variations can be made to the present embodiments without departing from the scope or spirit of the application. Thus, it is intended that the present application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

Claims

1. An anode composite catalyst layer between a proton exchange membrane and a gas diffusion layer of a membrane electrode, characterized by, The anode composite catalyst layer comprises: an iridium catalyst layer having opposite first and second surfaces, wherein the first surface faces the proton exchange membrane and the second surface faces the gas diffusion layer, the iridium catalyst layer comprising a first ionomer and an iridium catalyst dispersed in the first ionomer; a platinum conductive layer having opposite third and fourth surfaces, wherein the third surface is in contact with the second surface of the iridium catalyst layer and the fourth surface faces the gas diffusion layer, and the platinum conductive layer comprises a second ionomer and platinum nanoparticles having a particle size of 10-500 nm dispersed in the second ionomer.

2. The anode composite catalyst layer of claim 1, wherein The platinum nanoparticles have a particle size of 90-120 nm; the platinum conductive layer has a thickness of 0.3-1.5 μm; and the mass ratio of the platinum nanoparticles to the second ionomer is 1:(0.35-0.9).

3. The anode composite catalyst layer of claim 1, wherein The first ionomer and the second ionomer each comprise one or more of Nafion D2020, Nafion NR50, Aquivion D79-25B, and HCD-1820.

4. The anode composite catalyst layer according to any one of claims 1 to 3, characterized by, IrO2, IrRuO x1 , IrO2 / TiO2, IrO2 / NbO x1 , IrO2 / Ta2O5, IrO2 / WO x1 or IrO2 / Nb2O 5-x2 , wherein x1 is 1 to 2 and x2 is 0 to 3.

5. An anode composite catalyst layer slurry characterized by, The anode composite catalyst layer comprises: an iridium catalyst layer slurry comprising an iridium catalyst, a first ionomer, and a first solvent; a platinum conductive layer slurry comprising platinum nanoparticles having a particle size of 10-500 nm, a second ionomer, and a second solvent.

6. The anode composite catalyst layer slurry according to claim 5, wherein The mass ratio of the iridium catalyst, the first ionomer, and the first solvent is 1:(0.1-0.5):(5-50); and the mass ratio of the platinum nanoparticles, the second ionomer, and the second solvent is 1:(0.35-0.9):(10-50).

7. The anode composite catalyst layer slurry according to claim 5 or 6, characterized by, The first ionomer and the second ionomer each comprise one or more of Nafion D2020, Nafion NR50, Aquivion D79-25B, HCD-1820; the iridium catalyst is at least one of IrO2, IrRuO x , IrO2 / TiO2, IrO2 / NbO x , IrO2 / Ta2O5, IrO2 / WO x , or IrO2 / Nb2O 5-x ; the first solvent and the second solvent are the same or different and are selected from at least one of isopropyl alcohol, ethylene glycol, ethanol, n-propanol, and water.

8. A method for preparing an anode composite catalyst layer, characterized by, The anode composite catalyst layer is prepared using the anode composite catalyst layer slurry of any one of claims 5-7.

9. The method of claim 8, wherein the anode composite catalyst layer is prepared by mixing the anode catalyst layer and the anode binder layer. The preparation method comprises: forming an iridium catalyst layer on the surface of the proton exchange membrane of a membrane electrode using the iridium catalyst layer slurry and by a coating method or a transfer printing method; forming a platinum conductive layer on the surface of the iridium catalyst layer using the platinum conductive layer slurry and by a coating method or a transfer printing method; Alternatively, the preparation method comprises: forming a platinum conductive layer on a transfer material using the platinum conductive layer slurry and by a coating method or a transfer printing method; forming an iridium catalyst layer on the surface of the platinum conductive layer using the iridium catalyst layer slurry and by a coating method; transferring the laminated structure of the platinum conductive layer and the iridium catalyst layer to the surface of a proton exchange membrane by a transfer printing method, and removing the transfer material.

10. A membrane electrode characterized by, The membrane electrode comprises a proton exchange membrane, a gas diffusion layer, and the anode composite catalyst layer of any one of claims 1-4.

Images