Electrolytic water hydrogen production membrane electrode and preparation method thereof

Abstract

The application relates to an electrolytic water hydrogen production membrane electrode with a layered catalytic layer structure and a preparation method thereof. The method is characterized in that part of catalytic layer slurry is transferred onto a proton exchange membrane through hot pressing transfer printing to obtain a bottom catalytic layer with a compact and smooth surface, and then the remaining catalytic layer slurry is sprayed on the bottom catalytic layer by using a spraying method to obtain a layered structure membrane electrode. The layered structure membrane electrode can enhance the conductive contact between the catalytic layer and the diffusion layer, and strengthen the release and transmission of oxygen bubbles, thereby enhancing the performance of an electrolytic cell using the membrane electrode, improving the energy utilization efficiency during hydrogen production, and reducing the energy consumption of the electrolytic cell using the membrane electrode. The membrane electrode and the preparation method thereof are mainly used in the fields of proton exchange membrane electrolytic water hydrogen production and other related fields. Compared with the prior art, the application only needs to simply adjust the membrane electrode preparation process without using new materials and processes, and on the basis of not changing the existing production cost, the performance of the prepared membrane electrode is effectively improved.

Description

Technical Field

[0001] This invention relates to a water electrolysis hydrogen production membrane electrode and its preparation method, and more particularly to a water electrolysis hydrogen production membrane electrode with a layered catalytic layer structure and its preparation method. Background Technology

[0002] A proton exchange membrane electrolyzer is an important electrochemical device that converts electrical energy into chemical energy. Its structure is as follows: Figure 1 As shown, it mainly consists of a water electrolysis hydrogen production membrane electrode 1, a gas diffusion layer 2 (such as a porous titanium diffusion layer), and a bipolar plate 3, and is used for applications such as water electrolysis hydrogen production. The membrane electrode is the core component of the proton exchange membrane electrolyzer, determining the energy utilization efficiency and energy consumption of the proton exchange membrane electrolyzer. The basic structure of the membrane electrode is as follows: Figure 2 As shown, it mainly consists of an anode 12, a cathode 13, and a proton exchange membrane 11, with the anode and cathode located on opposite sides of the proton exchange membrane 11 and in close contact with it. The anode 12 and cathode 13 are typically covered with a noble metal catalyst layer, such as platinum and iridium, to promote the dissociation of water and the generation of hydrogen / oxygen.

[0003] The catalyst layer of a membrane electrode assembly (MEA) is typically prepared using either hot-press transfer or spraying methods. Both methods involve preparing a slurry of catalyst and alcohol solvent, which is then deposited onto a proton exchange membrane (PEM) as the catalyst layer. However, both methods result in catalyst layer structures with certain defects. Hot-press transfer involves transferring a pre-deposited catalyst layer onto a Teflon membrane using heat and pressure. Due to the heat and pressure, this method produces a denser and smoother catalyst layer structure, which is beneficial for conductive contact between the catalyst layer and the porous titanium diffusion layer. However, this method also reshapes the catalyst layer structure due to heat and pressure, resulting in a dense ionomer layer on the catalyst layer surface that hinders the transport of oxygen bubbles generated during internal electrolysis, thus reducing the MEA performance. The spraying method involves directly spraying the catalyst slurry onto the proton exchange membrane to deposit it as a catalyst layer. The resulting catalyst layer has a more porous structure and is less prone to forming a dense ionomer layer on the surface, which is beneficial for the transport of oxygen bubbles. However, the direct contact between the alcohol solvent in the catalyst slurry and the proton exchange membrane causes deformation of the proton exchange membrane, resulting in an unevenly distributed catalyst layer structure. This is not conducive to the conductive contact between the catalyst layer and the porous titanium diffusion layer, and reduces the performance of the membrane electrode.

[0004] Patent application CN115125549A discloses a method for preparing a low-iridium membrane electrode for hydrogen production via water electrolysis. By using a supported one-dimensional ordered array structure for the low-iridium membrane electrode, the polarization effect of mass transfer can be reduced, effectively transferring water molecules, electrons, and heat. This increases the three-phase contact area between the noble metal catalyst, the support, and water, improving the performance of the noble metal, reducing the amount of noble metal used, and increasing the utilization rate of the noble metal. However, the preparation process first involves catalyst growth on a hard titanium plate, adding an extra step. This significantly increases the cost and makes the mass production of the membrane electrode unsuitable. Furthermore, this method still uses a hot-press transfer method to prepare the surface catalyst layer, which can still lead to performance degradation due to mass transfer polarization caused by the presence of a dense ionomer layer on the surface.

[0005] Patent application CN116936888A discloses an asymmetric integrated gas diffusion membrane electrode and its fabrication method. The fabrication method includes the following steps: coating a substrate with a layer of perfluorosulfonic acid solution, then covering the catalytic layer of the gas diffusion electrode onto the surface of the perfluorosulfonic acid solution, followed by heat treatment to obtain component A; and depositing a catalyst on the membrane side of component A to prepare the asymmetric integrated membrane electrode. This membrane electrode exhibits high durability and stability, and the fabrication method is simple and convenient. However, this membrane electrode involves directly depositing the catalyst onto the proton exchange membrane, which leads to greater proton transport resistance, resulting in increased ohmic polarization and decreased performance.

[0006] In summary, existing membrane electrodes have the following technical problems: the presence of a dense ionomer layer or an inhomogeneous structure on the surface of the catalytic layer of the membrane electrode leads to a decrease in membrane electrode performance, which severely limits the commercial application of membrane electrode electrolysis for hydrogen production. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art by providing an electrolytic water hydrogen production membrane electrode and its preparation method, thereby reducing the activation loss, ohmic loss and transport loss of the electrode.

[0008] The objective of this invention can be achieved through the following technical solution: a method for preparing a membrane electrode for hydrogen production by water electrolysis. The method first transfers a portion of the catalyst layer slurry onto a proton exchange membrane by hot pressing to obtain a bottom catalyst layer with a dense and flat surface. Then, the remaining catalyst layer slurry is sprayed onto it using a spraying method to obtain a layered membrane electrode.

[0009] Furthermore, the catalyst layer slurry comprises a catalyst, perfluorosulfonic acid ionomer, and solvent in a mass ratio of 1:(0.1-1):(40-60), wherein the mass ratio of the catalyst, perfluorosulfonic acid ionomer, and solvent is preferably 1:(0.2-0.4):(45-55), and more preferably 1:0.3:50.

[0010] Furthermore, the catalyst layer slurry is obtained by ultrasonically dispersing a mixture of catalyst, perfluorosulfonic acid ionomer, and solvent.

[0011] Furthermore, the perfluorosulfonic acid ionomer is... Alternatively, other perfluorosulfonic acid ionomers may be used, with ethanol or isopropanol as the solvent. A layered anode catalyst layer and a cathode catalyst layer are respectively disposed on both sides of the proton exchange membrane, wherein the catalyst used in the anode catalyst layer slurry is iridium dioxide or iridium black catalyst, and the catalyst used in the cathode catalyst layer slurry is a platinum catalyst.

[0012] Furthermore, the specific steps of the hot-press transfer are as follows: the catalyst layer slurry is deposited on the substrate using an ultrasonic spraying machine or a scraping method to obtain a hot-press sheet, and then the obtained hot-press sheet is covered on the surface of the perfluorosulfonic acid proton exchange membrane, hot-pressed, and then the substrate is removed to obtain a membrane electrode with a dense bottom catalyst layer.

[0013] Furthermore, the substrate is a Teflon film substrate;

[0014] The hot pressing pressure is 0.1-1 MPa, preferably 0.4-0.6 MPa, more preferably 0.5 MPa; the hot pressing temperature is 100℃-150℃, preferably 110℃-130℃, more preferably 120℃; and the hot pressing time is 1-10 min, preferably 2-4 min, more preferably 3 min.

[0015] Furthermore, the pressure and temperature of hot pressing are used to regulate the flatness and density of the bottom dense layer, which depend on the catalyst loading of the membrane electrode.

[0016] Furthermore, the catalyst layer slurry is divided into two parts, one of which accounts for 40-60% (preferably 50%) of the total weight of the catalyst layer slurry and is transferred onto the proton exchange membrane by hot pressing, and the remaining part is loaded onto the surface of the catalyst layer obtained by hot pressing by spraying.

[0017] Furthermore, the ratio of the two catalyst layer slurries determines the thickness of the bottom dense layer of the membrane electrode, and the thickness of the bottom dense layer depends on the catalyst loading of the membrane electrode.

[0018] The present invention also provides a water electrolysis hydrogen production membrane electrode prepared by the aforementioned preparation method.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] (1) This invention combines spraying and hot-press transfer methods. First, a dense and flat bottom catalyst layer is obtained by hot-press transfer onto the proton exchange membrane. Then, a slurry is sprayed onto it. In this way, the alcohol solvent in the slurry will not directly contact the proton exchange membrane during spraying, thus avoiding membrane deformation. This results in a loose and flat surface structure without a dense ionomer layer. This layered membrane electrode design avoids the disadvantages of both hot-pressing and spraying methods and utilizes their advantages. On the one hand, the flat surface can enhance the conductive contact between the anode catalyst layer and the porous titanium diffusion layer, reducing ohmic losses. On the other hand, the porous and loose catalyst layer can also facilitate the removal of oxygen bubbles generated in the anode catalyst layer during electrolysis, reducing transport losses. This improves the performance of the proton exchange membrane electrode for water electrolysis to produce hydrogen and reduces the energy consumption of the electrolyzer.

[0021] (2) This invention improves the preparation process of the catalyst layer, enabling the catalyst layer of the membrane electrode, a core component in the proton exchange membrane electrolyzer, to form a layered structure. By enhancing the conductive contact between the catalyst layer and the diffusion layer, and strengthening the evolution and transport of oxygen bubbles at the anode during water electrolysis, the performance of the proton exchange membrane electrolysis water electrolysis hydrogen production membrane electrode is enhanced, improving the energy utilization efficiency during hydrogen production and reducing the energy consumption of the electrolyzer using this membrane electrode. This solves the problem that during the preparation of the proton exchange membrane electrolysis water stack membrane electrode, a dense ionomer layer that is non-conductive and hinders the transport of electrolyzed oxygen bubbles forms on the surface of the anode catalyst layer, leading to a decrease in membrane electrode performance.

[0022] (3) The membrane electrode preparation method of the present invention reduces the formation of a dense ionomer layer on the surface. The method is simple and low-cost. It only requires simple adjustment of the membrane electrode preparation process without the need for new materials and processes. It can significantly improve the performance of the water electrolysis hydrogen production membrane electrode and improve the energy utilization efficiency of the electrolysis hydrogen production in the electrolysis cell.

[0023] (3) The method described in this invention is applicable to the preparation of proton exchange membrane electrolysis water electrolysis hydrogen production electrolysis cells and membrane electrodes of proton exchange membrane electrolysis water electrolysis hydrogen production electrolysis cells, as well as other related fields. Attached Figure Description

[0024] Figure 1 A schematic diagram of the basic structure of an existing proton exchange membrane electrolyzer for water electrolysis.

[0025] Figure 2 This is a schematic diagram of the basic structure of a membrane electrode.

[0026] Figure 3 The diagram shows the structure of the anode catalyst layer prepared in Example 1 and Comparative Examples 1-2, where a is the anode catalyst layer prepared by spraying method in Comparative Example 1, b is the anode catalyst layer prepared by hot pressing transfer method in Comparative Example 2, and c is the anode catalyst layer prepared in Example 1.

[0027] Figure 4 This is a schematic diagram of the anode catalyst layer structure under an electron microscope for Comparative Example 2;

[0028] Figure 5 This is a schematic diagram of the anode catalyst layer structure under an electron microscope in Comparative Example 1;

[0029] Figure 6 To illustrate the electrode performance of the anodic membrane electrodes in Comparative Examples 1-2, Spray in the figure represents the membrane electrode prepared by the spray coating method, and HotPress represents the membrane electrode prepared by the hot pressing transfer method.

[0030] Figure 7 The membrane electrode performance of Example 1 is compared with that of Comparative Examples 1-2, where a is the electrolytic cell voltage of Example 1 and Comparative Examples 1-2 under different electrolytic current densities, and b is the polarization performance loss (activation loss, ohmic loss and transport loss) of Example 1 and Comparative Examples 1-2 under different electrolytic current densities. In the figure, Spray represents the membrane electrode prepared by spray coating, HotPress represents the membrane electrode prepared by hot pressing transfer, and Hierarchical represents the layered membrane electrode. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0032] This invention relates to a novel proton exchange membrane electrode for hydrogen production via water electrolysis, which has a layered catalytic layer structure and is prepared by the following method:

[0033] S1, Preparation of the anode catalyst layer slurry: The catalyst (such as iridium dioxide or iridium black catalyst) is mixed with a perfluorosulfonic acid ionomer (such as... The solvent (such as ethanol or isopropanol) is mixed at a mass ratio of 1:(0.1-1):(40-60), and then dispersed by ultrasonic dispersion for 30 minutes to obtain the anode catalyst layer slurry.

[0034] S2, Preparation of Teflon hot-pressed sheets: 40-60% (preferably 50%) of the total weight of the prepared anode catalyst layer slurry is taken as the slurry for hot pressing the bottom dense layer. The amount of this slurry determines the thickness of the bottom dense layer of the membrane electrode, which depends on the catalyst loading of the membrane electrode. The catalyst layer slurry is deposited on the Teflon film substrate using an ultrasonic spraying machine or a blade coating method to obtain the Teflon hot-pressed sheet.

[0035] S3, Preparation of the bottom dense layer of the membrane electrode by hot pressing transfer method: Teflon hot press sheets are cut to the required size and covered on the surface of the perfluorosulfonic acid proton exchange membrane. A pressure of 0.1-1 MPa is applied using a hot press at a temperature of 100℃-150℃ for 1-10 minutes. The pressure and temperature of the hot press are adjustable, both of which can be used to control the flatness and density of the bottom dense layer. The flatness and density of the bottom dense layer depend on the catalyst loading of the membrane electrode.

[0036] After hot pressing, the Teflon film is removed to obtain a membrane electrode with a dense catalytic layer at the bottom.

[0037] S4, Spray coating to add a top loose layer to the membrane electrode: Using a spray coating machine, the remaining catalyst layer slurry that was not removed by the hot-press transfer method is sprayed onto the surface of the membrane electrode with the underlying dense catalyst layer obtained in step S3. The spraying pressure is 2-3 bar, the nozzle working distance is 5-10 cm, the spraying gas flow rate is 2-5 L / min, and the spraying temperature is 80-100℃. The amount of slurry used determines the thickness of the top loose layer of the membrane electrode, and the thickness of the top loose layer depends on the catalyst loading of the membrane electrode. After spraying, a layered anode catalyst layer of the membrane electrode is obtained.

[0038] S5, Preparation of cathode catalyst layer slurry: The catalyst (such as a platinum catalyst) is mixed with a perfluorosulfonic acid ionomer (such as... The solvent (such as ethanol or isopropanol) is mixed at a mass ratio of 1:(0.1-1):(40-60), and then dispersed by ultrasonic dispersion for 30 minutes to obtain the cathode catalyst layer slurry.

[0039] S6. The cathode catalyst layer slurry obtained in step S5 is used to prepare a layered cathode catalyst layer on the other side of the membrane electrode obtained in step S4, according to steps S2-S4.

[0040] S7, see S7. Figure 2 In step S6, a porous titanium diffusion layer is deposited on both sides of the membrane electrode with anodic and cathode catalytic layers, and the membrane electrode is further assembled to obtain a membrane electrode, which is then applied in applications such as... Figure 1 In the proton exchange membrane electrolysis water electrolysis cell shown.

[0041] The raw materials and equipment used in this invention are all conventional in the field, such as Accelerate (Accelerate Ir Black); iridium dioxide is from Shengerno (SIR85 catalyst); and iridium black catalyst is from Accelerate (Accelerate Ir Black). The perfluorosulfonic acid ionomer is commercially available. Or other perfluorosulfonic acid ionomers.

[0042] Example 1

[0043] A proton exchange membrane electrode for water electrolysis to produce hydrogen with a layered catalytic layer structure, wherein the anode catalytic layer is prepared by the following method:

[0044] S1, iridium dioxide, The catalyst layer slurry was obtained by mixing ethanol and ethanol at a mass ratio of 1:0.3:50 and ultrasonically dispersing for 30 minutes.

[0045] S2, 50% of the prepared catalyst layer slurry is taken out and deposited on a Teflon film substrate using an ultrasonic spraying machine to obtain a Teflon hot press sheet.

[0046] S3. Cut the Teflon hot-pressed sheet to the required size and cover it on the surface of the perfluorosulfonic acid proton exchange membrane. Apply a pressure of 0.5 MPa to it using a hot press at 120°C for 3 minutes. After hot pressing, remove the Teflon film to obtain a membrane electrode with a dense catalytic layer at the bottom.

[0047] S4. Use a spraying method to add an upper fluffy layer to the membrane electrode: Use a spraying machine to spray the remaining 50% of the slurry that was not taken by the hot pressing transfer method, and deposit it on the surface of the membrane electrode with the underlying dense catalyst layer to obtain the anode catalyst layer of the layered membrane electrode.

[0048] S5, Preparation of cathode catalyst layer slurry: Platinum catalyst, The cathode catalyst layer slurry was obtained by mixing ethanol and ethanol at a mass ratio of 1:0.3:50 and ultrasonically dispersing for 30 minutes.

[0049] S6, the cathode catalyst layer slurry obtained in step S5 is used to prepare a layered cathode catalyst layer on the other side of the membrane electrode obtained in step S4, according to steps S2-S4.

[0050] S7, see S7. Figure 2 In step S6, a porous titanium diffusion layer is deposited on both sides of the membrane electrode with anodic and cathode catalytic layers, and the membrane electrode is further assembled to obtain a membrane electrode, which is then applied in applications such as... Figure 1 In the proton exchange membrane electrolysis water electrolysis cell shown.

[0051] Figure 3 c shows the anodic catalyst layer structure of the membrane electrode prepared in Example 1.

[0052] Comparative Example 1

[0053] The anodic and cathode catalyst layers were prepared by spraying. Specifically, the catalyst slurry obtained in step S1 of Example 1 was sprayed entirely onto the perfluorosulfonic acid proton exchange membrane using the spraying method in step S4. The rest was the same as in Example 1. Figure 3 a is a schematic diagram of the anodic catalyst layer structure of the membrane electrode prepared in Comparative Example 1. Figure 5 The structure of the anodic catalyst layer of the membrane electrode prepared in Comparative Example 1 is shown under an electron microscope, revealing its porous surface structure.

[0054] Comparative Example 2

[0055] The anodic and cathode catalyst layers were prepared using a hot-press transfer method. Specifically, the catalyst slurry obtained in step S1 of Example 1 was transferred entirely onto the perfluorosulfonic acid proton exchange membrane using the methods described in steps S2-S3. The rest was the same as in Example 1. Figure 3 b is a schematic diagram of the anode catalyst layer structure of the membrane electrode prepared in Comparative Example 2. Figure 4 The structure of the anodic catalyst layer of the membrane electrode prepared in Comparative Example 2 is shown under an electron microscope, revealing that its surface structure is smooth and dense.

[0056] See Figure 3 As can be seen from the figure, in Example 1, a dense and flat bottom catalyst layer was first obtained by hot-pressing transfer onto the proton exchange membrane. Then, a slurry was sprayed onto it using a spraying method. This prevents the alcohol solvent in the slurry from directly contacting the proton exchange membrane and causing membrane deformation, thus resulting in a loose, flat surface structure without a dense ionomer layer. Example 1 overcomes the shortcomings of the methods in Comparative Examples 1 and 2.

[0057] The membrane electrodes prepared in Example 1 and Comparative Examples 1-2 were assembled in an electrolytic cell for performance testing. The testing methods and conditions are as follows:

[0058] Test conditions: In an electrolytic cell with an active area of ​​2cm*2cm, using water at 80℃, an anode water supply rate of 10ml / min, the IV curve was tested (1~4A / cm). 2 The ohmic resistance at various current densities was measured using high-frequency impedance testing (HFR, test frequency 100KHz~100Hz).

[0059] Based on the IV curve and ohmic resistance, the voltage of the electrolytic cell can be decomposed into the following voltages:

[0060] V 电解池 =V 可逆电压 +V 活化损失 +V 欧姆损失 +V 传输损失

[0061] Where V 可逆电压 The reversible voltage for water electrolysis can be approximated by 1.23V in engineering applications, and 1.23V will be used for calculations thereafter.

[0062] The activation loss is obtained as follows: V 活化损失= b*log10(i / i0)

[0063] Where b is the Tafel slope (V / dec) of the IV curve fitted by subtracting the ohmic voltage drop in the current density range of 0-0.1A from the IV curve. i0 is the apparent exchange current density, and i0 is the intersection of the Tafel fitted curve and the x-axis.

[0064] The ohmic loss is obtained by measuring the ohmic resistance at each current density. The ohmic loss can be calculated using the following formula:

[0065] V 欧姆损失 = Current density * Ohmic loss at each current density

[0066] The transmission loss is obtained as follows:

[0067] According to V 电解池 =V 可逆电压 +V 活化损失 +V 欧姆损失 +V 传输损失

[0068] The total electrolytic cell voltage V under various current densities 电解池 Subtract the reversible voltage V under the response current 可逆电压 Activation loss V 活化损失 Ohm loss V 欧姆损失 The transmission loss V under each current can then be calculated. 传输损失 .

[0069] The test results are as follows:

[0070] <![CDATA[1Acm -2 ]]> Example 1 Comparative Example 1 Comparative Example 2 Activation loss (mV) 310 315 320 Ohmic loss (millivolts) 110 130 135 Transmission loss (millivolts) 30 33 32

[0071] <![CDATA[2Acm -2 ]]> Example 1 Comparative Example 1 Comparative Example 2 Activation loss (mV) 325 326 322 Ohmic loss (millivolts) 211 223 231 Transmission loss (millivolts) 42 56 63

[0072] <![CDATA[3A cm -2 ]]> Example 1 Comparative Example 1 Comparative Example 2 Activation loss (mV) 337 339 334 Ohmic loss (millivolts) 332 346 358 Transmission loss (millivolts) 53 135 157

[0073] <![CDATA[4A cm -2 ]]> Example 1 Comparative Example 1 Comparative Example 2 Activation loss (mV) 353 356 348 Ohmic loss (millivolts) 425 451 463 Transmission loss (millivolts) 80 193 212

[0074] Based on the table above Figure 6-7 It can be seen that after using the membrane electrode design of the present invention, the transmission loss of Example 1 increases with current density at a much lower rate than that of Comparative Examples 1-2. At the same time, compared with Comparative Examples 1-2, the ohmic loss and transmission loss of Example 1 are both lower.

[0075] Figure 6The membrane electrode performance of Comparative Examples 1-2 is shown. It can be seen that, due to its denser and smoother surface structure, the membrane electrode of Comparative Example 2 provides better electron conduction, resulting in lower ohmic loss. However, the denser and smoother surface structure of the membrane electrode of Comparative Example 2 also hinders the outward transport of oxygen bubbles generated within the catalyst layer, thus causing greater transport loss than that of the membrane electrode of Comparative Example 1.

[0076] Figure 7 The membrane electrode performance of Example 1 compared to Comparative Examples 1-2 is shown. Figure 7 As shown, the layered membrane electrode exhibits better performance than the membrane electrode prepared by the hot-press transfer method and the anolyte membrane electrode prepared by the spraying method. Regarding the composition of polarization performance losses, Example 1 exhibits the lowest ohmic and transport losses. This is due to its inheritance of the advantages of the catalyst layer structure obtained by both the hot-press transfer and spraying methods: the dense bottom layer ensures the overall flatness of the membrane electrode and excellent conductive contact with the titanium diffusion layer, reducing ohmic losses. The fluffy surface layer provides a more efficient bubble transport channel, promptly removing gases generated during electrolysis and reducing transport losses.

[0077] Reducing the formation of a dense ionomer layer on the surface can significantly improve the performance of the membrane electrode for hydrogen production by water electrolysis, and improve the energy utilization efficiency of hydrogen production by electrolysis in the electrolyzer.

[0078] Example 2

[0079] A proton exchange membrane electrode for water electrolysis to produce hydrogen with a layered catalytic layer structure, wherein the anode catalytic layer is prepared by the following method:

[0080] S1, iridium dioxide, The catalyst layer slurry was obtained by mixing ethanol and ethanol at a mass ratio of 1:0.3:50 and ultrasonically dispersing for 30 minutes.

[0081] S2, 40% of the prepared catalyst layer slurry is taken out and deposited on a Teflon film substrate using an ultrasonic spraying machine to obtain a Teflon hot press sheet.

[0082] S3. Cut the Teflon hot-pressed sheet to the required size and cover it on the surface of the perfluorosulfonic acid proton exchange membrane. Apply a pressure of 0.5 MPa to it using a hot press at 120°C for 3 minutes. After hot pressing, remove the Teflon film to obtain a membrane electrode with a dense catalytic layer at the bottom.

[0083] S4. Use a spraying method to add an upper loose layer to the membrane electrode: Use a spraying machine to spray the remaining 60% of the slurry that was not taken by the hot pressing transfer method, and deposit it on the surface of the membrane electrode with the underlying dense catalyst layer to obtain the anode catalyst layer of the layered membrane electrode.

[0084] S5, Preparation of cathode catalyst layer slurry: Platinum catalyst, The cathode catalyst layer slurry was obtained by mixing ethanol and ethanol at a mass ratio of 1:0.3:50 and ultrasonically dispersing for 30 minutes.

[0085] S6, the cathode catalyst layer slurry obtained in step S5 is used to prepare a layered cathode catalyst layer on the other side of the membrane electrode obtained in step S4, according to steps S2-S4.

[0086] S7, see S7. Figure 2 In step S6, a porous titanium diffusion layer is deposited on both sides of the membrane electrode with anodic and cathode catalytic layers, and the membrane electrode is further assembled to obtain a membrane electrode, which is then applied in applications such as... Figure 1 In the proton exchange membrane electrolysis water electrolysis cell shown.

[0087] Example 3

[0088] A proton exchange membrane electrode for water electrolysis to produce hydrogen with a layered catalytic layer structure, wherein the anode catalytic layer is prepared by the following method:

[0089] S1, iridium dioxide, The catalyst layer slurry was obtained by mixing isopropanol and isopropanol at a mass ratio of 1:0.3:50 and ultrasonically dispersing for 30 minutes.

[0090] S2, 50% of the prepared catalyst layer slurry is taken out and deposited on a Teflon film substrate using an ultrasonic spraying machine to obtain a Teflon hot press sheet.

[0091] S3. Cut the Teflon hot-pressed sheet to the required size and cover it on the surface of the perfluorosulfonic acid proton exchange membrane. Apply a pressure of 1 MPa to it using a hot press at a temperature of 120°C for 3 minutes. After hot pressing, remove the Teflon film to obtain a membrane electrode with a dense catalytic layer at the bottom.

[0092] S4. Use a spraying method to add an upper fluffy layer to the membrane electrode: Use a spraying machine to spray the remaining 50% of the slurry that was not taken by the hot pressing transfer method, and deposit it on the surface of the membrane electrode with the underlying dense catalyst layer to obtain the anode catalyst layer of the layered membrane electrode.

[0093] S5, Preparation of cathode catalyst layer slurry: Platinum catalyst, The cathode catalyst layer slurry was obtained by mixing ethanol and ethanol at a mass ratio of 1:0.3:50 and ultrasonically dispersing for 30 minutes.

[0094] S6, the cathode catalyst layer slurry obtained in step S5 is used to prepare a layered cathode catalyst layer on the other side of the membrane electrode obtained in step S4, according to steps S2-S4.

[0095] S7, see S7. Figure 2In step S6, a porous titanium diffusion layer is deposited on both sides of the membrane electrode with anodic and cathode catalytic layers, and the membrane electrode is further assembled to obtain a membrane electrode, which is then applied in applications such as... Figure 1 In the proton exchange membrane electrolysis water electrolysis cell shown.

[0096] Example 4

[0097] A proton exchange membrane electrode for water electrolysis to produce hydrogen with a layered catalytic layer structure, wherein the anode catalytic layer is prepared by the following method:

[0098] S1, iridium dioxide, The catalyst layer slurry was obtained by mixing ethanol and ethanol at a mass ratio of 1:0.3:50 and ultrasonically dispersing for 30 minutes.

[0099] S2, 50% of the prepared catalyst layer slurry is taken out and deposited on a Teflon film substrate using an ultrasonic spraying machine to obtain a Teflon hot press sheet.

[0100] S3. Cut the Teflon hot-pressed sheet to the required size and cover it on the surface of the perfluorosulfonic acid proton exchange membrane. Apply a pressure of 0.5 MPa to it using a hot press at 150°C for 3 minutes. After hot pressing, remove the Teflon film to obtain a membrane electrode with a dense catalytic layer at the bottom.

[0101] S4. Use a spraying method to add an upper fluffy layer to the membrane electrode: Use a spraying machine to spray the remaining 50% of the slurry that was not taken by the hot pressing transfer method, and deposit it on the surface of the membrane electrode with the underlying dense catalyst layer to obtain the anode catalyst layer of the layered membrane electrode.

[0102] S5, Preparation of cathode catalyst layer slurry: Platinum catalyst, The cathode catalyst layer slurry was obtained by mixing ethanol and ethanol at a mass ratio of 1:0.3:50 and ultrasonically dispersing for 30 minutes.

[0103] S6, the cathode catalyst layer slurry obtained in step S5 is used to prepare a layered cathode catalyst layer on the other side of the membrane electrode obtained in step S4, according to steps S2-S4.

[0104] S7, see S7. Figure 2 In step S6, a porous titanium diffusion layer is deposited on both sides of the membrane electrode with anodic and cathode catalytic layers, and the membrane electrode is further assembled to obtain a membrane electrode, which is then applied in applications such as... Figure 1 In the proton exchange membrane electrolysis water electrolysis cell shown.

[0105] Example 5

[0106] A proton exchange membrane electrode for water electrolysis to produce hydrogen with a layered catalytic layer structure, wherein the anode catalytic layer is prepared by the following method:

[0107] S1, iridium dioxide, The catalyst layer slurry was obtained by mixing ethanol and ethanol at a mass ratio of 1:0.3:50 and ultrasonically dispersing for 30 minutes.

[0108] S2, 50% of the prepared catalyst layer slurry is taken out and deposited on a Teflon film substrate using an ultrasonic spraying machine to obtain a Teflon hot press sheet.

[0109] S3. Cut the Teflon hot-pressed sheet to the required size and cover it on the surface of the perfluorosulfonic acid proton exchange membrane. Apply a pressure of 0.5 MPa to it using a hot press at 120°C for 10 minutes. After hot pressing, remove the Teflon film to obtain a membrane electrode with a dense catalytic layer at the bottom.

[0110] S4. Use a spraying method to add an upper fluffy layer to the membrane electrode: Use a spraying machine to spray the remaining 50% of the slurry that was not taken by the hot pressing transfer method, and deposit it on the surface of the membrane electrode with the underlying dense catalyst layer to obtain the anode catalyst layer of the layered membrane electrode.

[0111] S5, Preparation of cathode catalyst layer slurry: Platinum catalyst, The cathode catalyst layer slurry was obtained by mixing ethanol and ethanol at a mass ratio of 1:0.3:50 and ultrasonically dispersing for 30 minutes.

[0112] S6, the cathode catalyst layer slurry obtained in step S5 is used to prepare a layered cathode catalyst layer on the other side of the membrane electrode obtained in step S4, according to steps S2-S4.

[0113] S7, see S7. Figure 2 In step S6, a porous titanium diffusion layer is deposited on both sides of the membrane electrode with anodic and cathode catalytic layers, and the membrane electrode is further assembled to obtain a membrane electrode, which is then applied in applications such as... Figure 1 In the proton exchange membrane electrolysis water electrolysis cell shown.

[0114] Example 6

[0115] A proton exchange membrane electrode for water electrolysis to produce hydrogen with a layered catalytic layer structure, wherein the anode catalytic layer is prepared by the following method:

[0116] S1, iridium dioxide, The catalyst layer slurry was obtained by mixing ethanol and ethanol at a mass ratio of 1:1:60 and ultrasonically dispersing for 30 minutes.

[0117] S2, 50% of the prepared catalyst layer slurry is taken out and deposited on a Teflon film substrate using an ultrasonic spraying machine to obtain a Teflon hot press sheet.

[0118] S3. Cut the Teflon hot-pressed sheet to the required size and cover it on the surface of the perfluorosulfonic acid proton exchange membrane. Apply a pressure of 0.5 MPa to it using a hot press at 120°C for 3 minutes. After hot pressing, remove the Teflon film to obtain a membrane electrode with a dense catalytic layer at the bottom.

[0119] S4. Use a spraying method to add an upper fluffy layer to the membrane electrode: Use a spraying machine to spray the remaining 50% of the slurry that was not taken by the hot pressing transfer method, and deposit it on the surface of the membrane electrode with the underlying dense catalyst layer to obtain the anode catalyst layer of the layered membrane electrode.

[0120] S5, Preparation of cathode catalyst layer slurry: Platinum catalyst, The cathode catalyst layer slurry was obtained by mixing ethanol and ethanol at a mass ratio of 1:1:60 and ultrasonically dispersing for 30 minutes.

[0121] S6, the cathode catalyst layer slurry obtained in step S5 is used to prepare a layered cathode catalyst layer on the other side of the membrane electrode obtained in step S4, according to steps S2-S4.

[0122] S7, see S7. Figure 2 In step S6, a porous titanium diffusion layer is deposited on both sides of the membrane electrode with anodic and cathode catalytic layers, and the membrane electrode is further assembled to obtain a membrane electrode, which is then applied in applications such as... Figure 1 In the proton exchange membrane electrolysis water electrolysis cell shown.

[0123] The products obtained in Examples 2-6 were tested using the method described in Example 1 above, and the results are as follows:

[0124] The test results are as follows:

[0125] <![CDATA[4A cm -2 ]]> Example 2 Example 3 Example 4 Example 4 Example 5 Example 6 Activation loss (mV) 363 384 359 358 393 382 Ohmic loss (millivolts) 423 435 431 434 441 439 Transmission loss (millivolts) 95 93 99 101 87 75

[0126] As can be seen from the table above, the products obtained in Examples 2-6 also have less ohmic loss and transmission loss.

[0127] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from the principles of the invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a membrane electrode for hydrogen production by water electrolysis, characterized in that, The method first transfers a portion of the catalyst layer slurry onto a proton exchange membrane via hot pressing to obtain a dense and flat bottom catalyst layer. Then, the remaining catalyst layer slurry is sprayed onto it using a spraying method to obtain a layered membrane electrode. The specific steps of the hot-press transfer are as follows: the catalyst layer slurry is deposited on the substrate using an ultrasonic spraying machine or a scraping method to obtain a hot-press sheet, and then the obtained hot-press sheet is covered on the surface of the proton exchange membrane, hot-pressed, and then the substrate is removed to obtain a membrane electrode with a dense bottom catalyst layer. The substrate is a Teflon film substrate; the hot pressing pressure is 0.1-1 MPa, the hot pressing temperature is 100℃-150℃, and the hot pressing time is 1-10 min.

2. The method for preparing a water electrolysis hydrogen production membrane electrode according to claim 1, characterized in that, The catalyst layer slurry comprises a catalyst, perfluorosulfonic acid ionomer, and solvent in a mass ratio of 1:(0.1-1):(40-60).

3. The method for preparing a water electrolysis hydrogen production membrane electrode according to claim 2, characterized in that, The catalyst layer slurry is obtained by ultrasonically dispersing a mixture of catalyst, perfluorosulfonic acid ionomer, and solvent.

4. The method for preparing a water electrolysis hydrogen production membrane electrode according to claim 3, characterized in that, The perfluorosulfonic acid ionomer is Nafion. ® The solvent is ethanol or isopropanol; The proton exchange membrane is provided with a layered anode catalyst layer and a cathode catalyst layer on both sides. The catalyst used in the anode catalyst layer slurry is iridium dioxide or iridium black catalyst, and the catalyst used in the cathode catalyst layer slurry is platinum catalyst.

5. The method for preparing a water electrolysis hydrogen production membrane electrode according to claim 1, characterized in that, The catalyst layer slurry is divided into two parts. One part, accounting for 40-60% of the total weight of the catalyst layer slurry, is transferred onto the proton exchange membrane by hot pressing, and the remaining part is loaded onto the surface of the catalyst layer obtained by hot pressing by spraying.

6. A water electrolysis hydrogen production membrane electrode prepared by any one of the preparation methods described in claims 1-5.

7. The water electrolysis hydrogen production membrane electrode according to claim 6, characterized in that, It includes a proton exchange membrane and an anode catalyst layer and a cathode catalyst layer disposed on both sides thereof. The anode catalyst layer and the cathode catalyst layer are both dense and flat bottom catalyst layer and porous and fluffy surface catalyst layer disposed sequentially on the surface of the proton exchange membrane.

8. The water electrolysis hydrogen production membrane electrode according to claim 7, characterized in that, The bottom catalyst layer has a thickness of 7 micrometers, the surface catalyst layer has a thickness of 3 micrometers, the bottom catalyst layer has a porosity of 40-60%, and the surface catalyst layer has a porosity of 60-80%.

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