A kind of hydrogen production membrane electrode of alkaline membrane electrolytic water and hydrogen production device based on it

Abstract

The application provides a hydrogen production membrane electrode for alkaline membrane water electrolysis and a hydrogen production device based on the same, which comprises an alkaline membrane and an anode diffusion electrode and a cathode diffusion electrode separately arranged on two sides of the alkaline membrane; the anode (cathode) diffusion electrode is formed with an anode (cathode) catalyst layer on one side of an anode (cathode) porous diffusion layer by spraying an anode (cathode) catalyst slurry; the anode (cathode) catalyst slurry contains anode (cathode) catalyst powder and an alkaline ionomer containing cross-linking sites; and the cross-linking sites of the alkaline ionomer are heat-crosslinked to fix the anode (cathode) catalyst layer by heating when the anode (cathode) catalyst layer is prepared by spraying. The hydrogen production membrane electrode for alkaline membrane water electrolysis has the advantages of low resistance, high water electrolysis hydrogen production current density, resistance to electrolyte scouring, resistance to high potential, good stability and the like, and the whole membrane electrode preparation process is simple and free of additional complex steps.

Description

Technical Field

[0001] This invention belongs to the field of alkaline membrane electrolysis for hydrogen production technology, specifically relating to an alkaline membrane electrolysis membrane electrode for hydrogen production and an electrolysis device based thereon. Background Technology

[0002] Hydrogen production technology through water electrolysis has evolved into numerous types, generally categorized based on the electrolyte used: alkaline water electrolysis (AWEs), proton exchange membrane water electrolysis (PEMWEs), alkaline membrane water electrolysis (AEMWEs), and solid oxide electrolyzers (SOECs). AWEs are the earliest developed, lowest-cost, most commercially viable, and most stable, and are currently the most widely used. Unlike AWEs, PEMWEs are compatible with frequent changes in current loads, a crucial characteristic for energy conversion from renewable energy sources. PEMWEs benefit from the highly commercialized perfluorosulfonic acid proton exchange membrane (Nafion) developed by DuPont, and are currently the most researched and fastest-developing, achieving partial commercialization. AEMWEs combine the low cost of AWEs with the high efficiency of PEMWEs, attracting increasing attention from researchers. All these technologies have their advantages and disadvantages, and the challenge of reducing the cost of hydrogen production depends on the technology itself. Alkaline membrane water electrolysis offers unparalleled cost advantages by using non-precious metal catalysts. The core components of alkaline membrane electrolysis for hydrogen production are the membrane electrode and the electrolysis device. The membrane electrode directly determines the performance and stability of alkaline membrane electrolysis, and consequently, the efficiency and stability of the device. The theoretical voltage for water electrolysis is 1.23V, but the actual operating voltage is much higher due to the high resistance and poor catalytic performance of the membrane electrode. The stability of the membrane electrode directly determines the lifespan of the alkaline membrane electrolysis device, thus affecting its commercial application. Traditional methods for preparing the membrane electrode involve directly spraying a mixture of alkaline ionomer solution and catalyst. However, the high potential and repeated scouring of the electrode by the electrolyte lead to extreme instability of the catalyst layer within the membrane electrode. Furthermore, the alkaline membrane electrolysis device directly determines the internal resistance, operating voltage, and operational stability of the entire system. Therefore, the preparation of the membrane electrode and the electrolysis device are crucial for alkaline membrane electrolysis. Summary of the Invention

[0003] To address the shortcomings of existing alkaline membrane electrolysis for hydrogen production, this invention provides an alkaline membrane electrolysis electrode and a hydrogen production device based thereon. By employing an in-situ thermal crosslinking strategy during the preparation of the alkaline membrane electrolysis electrode to stabilize the catalytic layer, the stability of the membrane electrode is enhanced, thereby increasing the stability of the hydrogen production device.

[0004] To achieve its objectives, the present invention employs the following technical solution:

[0005] This invention first provides an alkaline membrane electrode for water electrolysis to produce hydrogen, comprising an alkaline membrane and an anolyte diffusion electrode and a cathode diffusion electrode disposed on opposite sides of the alkaline membrane. The anolyte diffusion electrode has an anolyte catalyst layer formed by spraying an anolyte catalyst slurry onto one side of the porous anolyte diffusion layer, the anolyte catalyst layer being close to the alkaline membrane. The cathode diffusion electrode has a cathode catalyst layer formed by spraying a cathode catalyst slurry onto one side of the porous cathode diffusion layer, the cathode catalyst layer being close to the alkaline membrane. The anolyte catalyst slurry contains anolyte catalyst powder and an alkaline ionomer containing crosslinking sites, and the cathode catalyst slurry contains cathode catalyst powder and an alkaline ionomer containing crosslinking sites. During the spraying preparation of the anolyte and cathode catalyst layers, heating causes thermal crosslinking of the crosslinking sites of the alkaline ionomer, thereby fixing the anolyte and cathode catalyst layers.

[0006] Furthermore, the basic ionomer containing crosslinking sites contains carbon-carbon double bonds or carbon-carbon triple bonds, that is, the basic ionomer uses carbon-carbon double bonds or carbon-carbon triple bonds as crosslinking sites. The basic ionomer containing crosslinking sites is preferably at least one of polyphenylene, polyphenylene ether, polyetheretherketone, and polysulfone containing carbon-carbon double bonds or carbon-carbon triple bonds.

[0007] Furthermore, the basic ionomer containing crosslinking sites also contains basic anion exchange groups that conduct hydroxide ions, such as quaternary ammonium groups, quaternary phosphine groups, guanidinyl groups, imidazole groups, pyridine groups, pyrazole groups, piperidine groups, ferrocene groups, and cobalt diacene groups. These groups can bind anions and can dissociate to form migratory anions. For example, R4N... + OH - The group contains a dissociable OH group. - OH - It can migrate freely, thereby achieving the transfer of OH. - The purpose.

[0008] Furthermore, the mass ratio of anode catalyst powder to basic ionomer containing cross-linking sites in the anode catalyst slurry is 1:0.05-0.3, and the mass ratio of cathode catalyst powder to basic ionomer containing cross-linking sites in the cathode catalyst slurry is 1:0.05-0.3. Excessive basic ionomer content leads to an excessively thick layer of basic ionomer around the catalyst, hindering the diffusion and escape of gaseous products, reducing catalytic efficiency, and also resulting in an overly dense cross-linked network of basic ionomer in the catalyst layer, limiting the catalytic effect. Conversely, insufficient basic ionomer content results in insufficient basic ionomer around the catalyst in the catalyst layer to conduct hydroxide ions, hindering reactant transport, reducing catalytic efficiency, and also resulting in an overly loose cross-linked network of basic ionomer in the catalyst layer, insufficient to fix the catalyst layer.

[0009] Further: the anode catalyst is at least one of the following non-precious metal catalysts: NiFe catalyst, NiFeCo catalyst, CoFe catalyst, NiFeMo catalyst, FeCoMo catalyst, NiFeS catalyst, NiFeMn catalyst, NiFeCe catalyst, CoFeCr catalyst, and CoCu catalyst (all anode catalysts are non-precious metal catalysts and can only be used under alkaline conditions, not acidic conditions); the cathode catalyst is at least one of Pt / C catalyst and PtRu / C catalyst; the anode porous diffusion layer and the cathode porous diffusion layer are at least one of nickel foam, nickel-iron foam, iron foam, copper foam, titanium foam, nickel felt, titanium felt, stainless steel felt, carbon paper, and carbon cloth; the alkaline membrane is at least one of polyphenylene, polyphenylene ether, polyetheretherketone, and polysulfone containing alkaline anion exchange groups.

[0010] The present invention also provides a method for preparing the alkaline membrane electrode for water electrolysis to produce hydrogen, comprising the following steps:

[0011] Step 1: Prepare catalyst slurry

[0012] An alkaline ionomer containing crosslinking sites is added to a solvent to obtain an alkaline ionomer solution.

[0013] The anode catalyst powder was added to deionized water, then isopropanol was added, and then an alkaline ionomer solution was added. The resulting mixed solution was placed in an ultrasonic cell disruptor and ultrasonically dispersed evenly to obtain a uniform anode catalyst slurry.

[0014] The cathode catalyst powder was added to deionized water, then isopropanol was added, and then an alkaline ionomer solution was added. The resulting mixed solution was placed in an ultrasonic cell disruptor and ultrasonically dispersed evenly to obtain a uniform cathode catalyst slurry.

[0015] Step 2: Prepare diffusion electrode

[0016] The anode catalyst slurry is ultrasonically sprayed onto one side of the porous diffusion layer of the anode, and heating is started during the spraying process. The cross-linking sites on the alkaline ionomer cross-link with each other after being heated, fixing the catalyst, thereby obtaining a uniformly distributed and stable anode catalyst layer, and obtaining an anode diffusion electrode.

[0017] The cathode catalyst slurry is ultrasonically sprayed onto one side of the porous diffusion layer of the cathode, and heating is started during the spraying process. The cross-linking sites on the alkaline ionomer cross-link with each other after being heated, fixing the catalyst, thereby obtaining a cathode catalyst layer with uniform and stable catalyst distribution, and obtaining a cathode diffusion electrode.

[0018] Step 3: Preparation of alkaline membrane electrolysis water electrolysis hydrogen production membrane electrode

[0019] The anodic diffusion electrode and the cathode diffusion electrode are respectively attached tightly to both sides of the alkaline membrane, and then hot-pressed using a hot press to obtain the alkaline membrane electrolysis water production hydrogen membrane electrode.

[0020] Furthermore, in step 1, the mass ratio of catalyst powder, deionized water and isopropanol in the catalyst slurry is 0.1-1:1:3-6.

[0021] Further, in step 1, the solvent of the alkaline ionomer solution can be one of dimethyl sulfoxide, N-methylpyrrolidone, dimethylformamide, methanol, ethanol, and dichloromethane, and the mass concentration of the alkaline ionomer solution can be 2-5%.

[0022] Furthermore, in step 1, the ultrasound time is 0.5-2 hours.

[0023] Furthermore, in step 2, the heating temperature for thermal crosslinking is 60-120℃, and the heating time is 1-10 hours.

[0024] Furthermore, in step 3, the hot-pressing temperature is 60-150℃ and the pressure is 10-40 kg / cm². 2 Hot pressing time: 1-5 minutes.

[0025] Furthermore, the alkaline membrane electrolysis water-to-hydrogen membrane electrode can be immersed in KOH solution, causing the alkaline ionomer in the electrolysis water-to-hydrogen membrane electrode to replace the anion exchange groups of the alkaline membrane with OH groups. - Ions. Specifically: the concentration of the KOH solution can be set to 1M; the soaking time can be 2-48 hours; after soaking in the KOH solution, the electrode is then soaked in deionized water to wash away the surface KOH, and the deionized water is continuously replaced until the pH of the soaking deionized water is neutral.

[0026] The present invention also provides an alkaline membrane electrolysis water production hydrogen device, which includes the alkaline membrane electrolysis water production hydrogen production membrane electrode described above.

[0027] In the alkaline membrane electrolysis water production hydrogen production membrane electrode of the present invention: the alkaline membrane is a polymer membrane containing alkaline anion exchange groups, which is a membrane-like anion exchange resin that serves as an ion transport and barrier electrode. Rapid ion transport reduces the ion transport resistance of the anode and cathode, lowering the ohmic overpotential, while excellent barrier properties ensure the purity of the produced hydrogen. The alkaline membrane can also withstand alkaline environments and remain stable in alkaline solutions for extended periods. The catalyst slurry is prepared by mixing catalyst powder with an alkaline ionomer containing crosslinking sites. The catalyst slurry is then ultrasonically sprayed onto a porous diffusion layer to prepare a diffusion electrode. Heating during the spraying process causes the alkaline ionomer containing crosslinking sites in the catalyst layer to crosslink, fixing the catalyst layer. This processing method effectively maintains the adhesion between the catalyst layer and the porous diffusion layer and the internal stability of the catalyst layer, minimizing catalyst layer loss during alkaline membrane electrolysis water production hydrogen production, thereby improving the stability of alkaline membrane electrolysis water production hydrogen production. By hot-pressing the anodic diffusion electrode, the cathode diffusion electrode, and the alkaline membrane to prepare the membrane electrode, the interfacial mass transfer resistance can be reduced as much as possible, which is beneficial to ion transport, increases the mass transfer rate, and thus improves the efficiency of alkaline membrane water electrolysis for hydrogen production.

[0028] Compared with existing technologies, the beneficial effects of this invention are reflected in:

[0029] This invention provides a cross-linked, fixed alkaline membrane electrode for water electrolysis to produce hydrogen. It uses in-situ cross-linking to fix the catalyst layer, resulting in good stability and long service life. Simultaneously, its zero-gap structure accelerates the transport of ions between the anode and cathode, thereby significantly reducing the overpotential in alkaline membrane water electrolysis and greatly improving the efficiency of hydrogen production. The alkaline membrane electrode of this invention has many advantages, including low resistance, high current density in water electrolysis, resistance to electrolyte erosion, high potential resistance, and good stability. The entire membrane electrode preparation process is simple, without additional complex steps, and can be used long-term in alkaline membrane water electrolysis for hydrogen production. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the alkaline membrane water electrolysis hydrogen production device assembled in Embodiment 1 of the present invention.

[0032] Figure 2 The polarization curve of the alkaline membrane electrode for hydrogen production by water electrolysis prepared in Example 1 of the present invention under pure water feed conditions.

[0033] Figure 3 The voltage curve of the alkaline membrane electrolysis water production hydrogen production membrane electrode prepared in Example 1 of the present invention under pure water feed conditions.

[0034] Figure 4 The polarization curve of the alkaline membrane electrode for hydrogen production by water electrolysis prepared in Comparative Example 1 of the present invention under pure water feed conditions.

[0035] Figure 5 The voltage curve of the alkaline membrane electrode for hydrogen production by water electrolysis prepared in Comparative Example 1 of the present invention under pure water feed conditions is shown.

[0036] Figure 6 The polarization curves of the alkaline membrane electrolysis water production hydrogen production membrane electrodes prepared in Example 1 and Comparative Example 1 of the present invention under KOH feed conditions are shown.

[0037] Figure 7 These are synchrotron radiation Nano-CT images of the catalyst layer of the alkaline membrane electrolysis water production hydrogen production membrane electrode in Example 1 and Comparative Example 1 of the present invention. Figure 7 a and 7b are Nano-CT two-dimensional images of Example 1 and Comparative Example 1, respectively. Figure 7 c and 7d are the three-dimensional segmentation and reconstructed three-dimensional images of the catalyst agglomerates in the catalyst layer of Example 1 and Comparative Example 1, respectively.

[0038] Figure 8 This is a schematic diagram of the alkaline membrane electrolysis water production device in Embodiment 2 of the present invention.

[0039] Figure 9 This is a schematic diagram of the assembly of the alkaline membrane electrolysis water production device in Embodiment 2 of the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] 1. Preparation of a product containing ion exchange groups (I - Basic ionomers of (ion):

[0043] 8.28 g of terphenyl, 0.777 g of 9,9′-dimethylfluorene, and 4.98 g of 1-methyl-4-piperidinone were added to a 200 mL single-necked flask equipped with a mechanical stirrer. Then, 18 mL of dichloromethane was added to the reactor as a solvent. After cooling the solution to -3.2 °C using a cooler, trifluoroacetic acid (TFA, 4.8 mL) and trifluoromethanesulfonic acid (TFSA, 36 mL) were slowly added to the solution, and the reaction was carried out at -3.2 °C for approximately 12 hours. The color of the solution changed from yellow to dark red. Finally, the viscous solution was poured into 1 L of deionized water to precipitate the polymer, and stirring was continued in the water for 2 hours. After vacuum filtration, the polymer was dried in an oven at 80 °C. It was then dissolved in 40 mL of LDM, and the viscous solution was poured into 500 mL of a 1 mol / L NaOH solution to precipitate the polymer. Subsequently, the large polymer fibers were cut into smaller pieces using a mixer and stirred in NaOH solution for 48 hours. The mixture was then washed three times with deionized water until the pH was neutral. The polymer was dried in an oven at 80°C for 24 hours to obtain the poly(fluorene-coarylmethylpiperidine) polymer (PFAM-x).

[0044] The poly(fluorene-coarylmethylpiperidine) polymer was dissolved in dimethyl sulfoxide (30 mL) in a 100 mL single-necked flask equipped with a magnetic stirrer and stirred until the polymer was completely dissolved. Iodimethane (3 mL) was added to the polymer solution, and the reaction was carried out at room temperature in the dark with magnetic stirring for 24 hours. The polymer solution was precipitated in 300 mL of acetone and washed three times with deionized water to remove residual iodimethane. Finally, the polymer was dried overnight in an oven at 80 °C to obtain a pale yellow poly(fluorene-arylpiperidine) polymer (PFTP).

[0045] 2. Preparation of products containing ion exchange groups (I - Basic ionomers with ions and crosslinking sites:

[0046] 1.0 g of poly(fluorene-coarylmethylpiperidine) polymer was dissolved in 12 mL of dimethyl sulfoxide in a 50 mL single-necked flask equipped with a magnetic stirrer. Potassium carbonate (0.646 g) and chloromethylvinylbenzene (0.238 g) were then added to the polymer solution, and the reaction was carried out at room temperature with magnetic stirring for 24 hours. 2 mL of iodomethane was then added to the polymer solution, and the reaction was carried out at room temperature in the dark with magnetic stirring for 24 hours. The polymer solution was precipitated in 300 mL of acetone and washed three times with deionized water to remove residual iodomethane. Finally, the polymer was dried at room temperature to obtain a pale yellow poly(fluorene-arylpiperidine-methylstyrene) polymer (VBPFTP).

[0047] 3. Preparation of alkaline membranes

[0048] 0.4 g of poly(fluorene-arylpiperidine) polymer was dissolved in 14 mL of dimethyl sulfoxide to prepare a polymer solution. The polymer solution was then collected in a syringe, filtered through a 0.45 μm filter, and then uniformly cast onto a 10 × 10 cm glass plate. The polymer solution was dried on a hot plate at 80 °C for 24 hours to remove the solvent. Finally, the membrane was peeled off the glass plate to obtain an alkaline membrane with a thickness of 40 ± 5 μm. The alkaline membrane was then cut into 5 cm × 5 cm pieces.

[0049] 4. Preparation of diffusion electrodes

[0050] Poly(fluorene-arylpiperidine-methylstyrene) polymer (VBPFTP) was added to dimethyl sulfoxide solvent to obtain an alkaline ionomer solution with a mass concentration of 5%.

[0051] The anode porous diffusion layer (1.5 mm thick nickel-iron foam) and the cathode porous diffusion layer (1.5 mm thick carbon paper (Toray-H-060)) were ultrasonically treated in acetone for 30 minutes, then ultrasonically treated in 6M hydrochloric acid for 2 minutes, rinsed three times with deionized water, ultrasonically treated in 1M NaOH for 10 minutes, and then rinsed multiple times with deionized water for later use.

[0052] Anode diffusion electrode: 400 mg NiFe catalyst was added to 1 mL of deionized water, followed by 4 mL of isopropanol and an alkaline ionomer solution (catalyst to alkaline ionomer mass ratio of 9:1). The mixture was ultrasonically treated in an ice-water bath for 1 hour to obtain a well-dispersed anode catalyst slurry. The anode catalyst slurry was then sprayed onto a 10 cm × 10 cm nickel-iron foam using an ultrasonic sprayer at a flow rate of 0.4 mL / min, resulting in a catalyst loading of 4.0 mg / cm³. 2 The anode diffusion electrode. The distance between the nozzle and the surface of the foamed nickel-iron is always maintained at 5 cm.

[0053] Cathode diffusion electrode: 500 mg PtRu / C powder was added to 4 mL of deionized water, followed by slow addition of 16 mL of isopropanol and an alkaline ionomer solution (catalyst to alkaline ionomer mass ratio of 3:1). The mixture was ultrasonically treated in an ice-water bath for 1 hour to obtain a well-dispersed cathode catalyst slurry. The cathode catalyst slurry was then sprayed onto 10 cm × 10 cm carbon paper using an ultrasonic sprayer at a flow rate of 0.4 mL / min, resulting in a platinum loading of 0.5 mg / cm². 2 The cathode diffusion electrode. The distance between the nozzle and the surface of the foamed nickel-iron is always maintained at 5 cm.

[0054] During the preparation of the anodic and cathodic diffusion electrodes, the diffusion layer was heated on a hot plate at 60°C and adsorbed onto a vacuum adsorption stage during the spraying process. After spraying, the diffusion electrode containing the poly(fluorene-arylpiperidine-methylstyrene) polymer was further heated on a hot plate at 60°C for 2 hours to completely convert the poly(fluorene-arylpiperidine-methylstyrene) polymer into a cross-linked form, thus fixing the catalyst layer.

[0055] 5. Preparation of alkaline membrane electrolysis water electrolysis hydrogen production membrane electrode

[0056] Cut the above-mentioned anodic and cathodic diffusion electrodes to a size of 2.25cm × 2.25cm. Attach the anodic and cathodic diffusion electrodes tightly to the center of both sides of the alkaline membrane, and then press them at 80℃ and 1MPa for 2 minutes using a hot press to obtain the alkaline membrane electrolysis water production hydrogen membrane electrode.

[0057] The alkaline membrane electrode for water electrolysis prepared in Example 1 was assembled and operated in an alkaline membrane water electrolysis hydrogen production device. The structure of the assembled alkaline membrane water electrolysis hydrogen production device is as follows. Figure 1 As shown.

[0058] The alkaline membrane water electrolysis hydrogen production unit was operated under the following conditions: operating temperature was room temperature or 80°C, the anode feed was pure water, and there was no feed to the cathode. The polarization curves of the above water electrolysis hydrogen production system were tested using the Wuhan LANHE battery testing system. The test results are as follows: Figure 2 As shown. By Figure 2 It can be seen that at 1.8V, the maximum current density of the alkaline membrane electrolysis system for hydrogen production with pure water feed reaches 920 mA / cm². 2 .

[0059] The alkaline membrane electrode for water electrolysis to produce hydrogen, prepared above, was immersed in 1.0 M KOH solution for 24 hours. The membrane electrode, gasket, bipolar plate, and end plate were then assembled into a unit with an effective area of ​​5 cm². 2 A single cell was constructed. The membrane electrode assembly (MEA) was placed between the titanium flow field at the anode and the graphite flow field at the cathode. The cell was first assembled with a torque of 5 Nm, followed by a torque of 7.5 Nm. Pure water was injected into the cell for circulation using a peristaltic pump. Single-cell testing was performed using a high-current cell testing system (5V / 20A, LANHE, Wuhan, China). The cell was then subjected to a 10 mA / cm² test. -2 Maintain this position for 5 minutes to ensure the battery does not short-circuit. Then, maintain the battery current density at 0.1 A / cm². - 2Five minutes were allowed to ensure the catalyst was in the proper oxidation state. The cell was operated at 1.8V until the current change did not exceed 1%. Polarization curves were recorded from 1.3V to 2.0V in increments of 0.05V at room temperature, with each voltage held for two minutes. All polarization curves (rising polarization curves) were measured from the lowest to the highest voltage. High-temperature polarization curves were achieved by heating the cell to 80°C, with the activation process identical to that at room temperature. The durability of hydrogen production via water electrolysis was measured using an electrochemical workstation at a constant current density. The high-frequency resistance (HFR) of the cell was recorded via a potential control module by applying an amplitude of 10mV at a frequency of 1kHz. The results are as follows: Figure 3 As shown in the figure. It can be seen that at a current density of 300 mA / cm², 2 The alkaline membrane electrolysis water production system can operate continuously for more than 120 hours with essentially no voltage change. Compared to traditional alkaline membrane electrolysis water production systems, the alkaline membrane electrolysis water production system assembled using the method provided by this invention exhibits significantly improved operational stability.

[0060] Comparative Example 1

[0061] The difference between the alkaline membrane electrolysis water production membrane electrode of this comparative example and Example 1 is that the polymer in the anode catalyst slurry and cathode catalyst slurry is replaced with a poly(fluorene-arylpiperidine) polymer (PFTP) solution.

[0062] The alkaline membrane electrode for water electrolysis and hydrogen production prepared in Comparative Example 1 was assembled into a water electrolysis and hydrogen production system and then run and tested according to the same method as in Example 1. The test results are as follows: Figure 4 As shown. By Figure 4 It can be seen that, using the alkaline membrane water electrolysis hydrogen production system prepared in Comparative Example 1, the current density of the alkaline membrane water electrolysis hydrogen production system is 720 mA / cm² at a voltage of 1.8 V. 2 . Figure 5 As can be seen, at a current density of 300 mA / cm² 2 At that time, the alkaline membrane electrolysis water production hydrogen system had poor stability during continuous operation, with the voltage continuously increasing within 100 hours and the performance degradation rate being 0.36mV / h.

[0063] The difference between Example 1 and Comparative Example 1 is that in Example 1, the alkaline ionomer containing crosslinking sites in the catalyst layer underwent a crosslinking reaction during the preparation of the alkaline membrane electrode for water electrolysis, thus fixing the catalyst layer; while the alkaline ionomer used in Comparative Example 1 lacked crosslinking sites, could not undergo crosslinking, and therefore could not fix the catalyst layer. It can be seen that the alkaline membrane electrode for water electrolysis provided by this invention, prepared by the method of crosslinking and fixing the catalyst layer, has better performance and superior stability.

[0064] Figure 6 The polarization curves of the alkaline membrane electrolysis water production hydrogen production membrane electrodes prepared in Example 1 and Comparative Example 1 for use in a water electrolysis hydrogen production system with a 1 MKOH aqueous solution feed are also provided. It can be seen that the alkaline membrane electrolysis water production hydrogen production membrane electrode prepared in Example 1 has better performance than the membrane electrode prepared in Comparative Example 1 at both room temperature and high temperature with a 1 MKOH aqueous solution feed.

[0065] As can be seen from the above embodiments, the present invention provides a method for preparing an alkaline membrane electrode for water electrolysis to produce hydrogen, comprising: spraying a catalyst slurry containing a catalyst and an alkaline ionomer containing crosslinking sites onto a porous diffusion layer and then performing thermal crosslinking to obtain a crosslinked and fixed catalyst layer and a diffusion electrode; hot-pressing the anode and cathode diffusion electrodes tightly against an alkaline membrane to obtain an alkaline membrane electrode for water electrolysis to produce hydrogen. The membrane electrode prepared by this method has good stability and can also reduce the ion transport resistance in the catalyst layer of the membrane electrode, resulting in an alkaline membrane electrode for water electrolysis to produce hydrogen with excellent performance and stability.

[0066] The catalyst layers from Examples 1 and 1 (Comparative Example 1) were scraped off from the porous diffusion layer, ultrasonically dispersed in an ultrasonic disperser, and then examined using a Nano-CT device under synchrotron radiation to obtain the morphology of the catalyst aggregates in the crosslinked and immobilized catalyst layers. Figure 7 As shown. Among them, Figure 7 a and 7b are Nano-CT two-dimensional images of Example 1 and Comparative Example 1, respectively. Figure 7 c and 7d are the 3D segmentation and reconstructed 3D images of the catalyst agglomerates in the catalyst layer of Example 1 and Comparative Example 1, respectively, using Nano-CT. The comparison shows that through the cross-linking fixation process, the basic ionomers spontaneously disperse around the catalyst agglomerates, resulting in more basic ionomers surrounding the catalyst agglomerates and a more uniform distribution, which is beneficial for ion transport within the catalyst layer.

[0067] Example 2

[0068] This embodiment provides an alkaline membrane electrolysis water production hydrogen device, such as... Figure 8 and Figure 9 As shown, this includes the alkaline membrane electrolysis water production membrane electrode of Example 1. Specifically, the alkaline membrane electrolysis water device provided in this example consists of an end plate, a current collector, an anode flow channel plate, an anode gasket, an anode diffusion electrode, an alkaline membrane, a cathode diffusion electrode, a cathode gasket, a cathode flow channel plate, a current collector, and an end plate.

[0069] The end plate is preferably made of titanium, nickel, stainless steel, or nickel-plated stainless steel, and has eight perfectly symmetrical threaded holes around its perimeter for securing the entire water electrolysis hydrogen production unit.

[0070] The end plate has heating holes at the front and rear for heating the device, and a temperature measuring hole at the top for placing a temperature sensor to monitor the temperature of the entire water electrolysis hydrogen production process.

[0071] The end plate has electrolyte inlet and outlet ports at the front and rear for circulating electrolyte inlet and outlet. The end plate has special flow channels to ensure normal electrolyte inlet and outlet.

[0072] The end plate, current collector, and flow channel plate are connected by a short section of polytetrafluoroethylene (PTFE) tubing. The electrolyte in the end plate flows into the flow channel plate through the PTFE tubing, and the electrolyte in the flow channel plate flows out through the PTFE connecting pipe. The connection is sealed by a silicone ring.

[0073] The current collector is preferably made of gold-plated brass or brass. A connection hole is opened in the current collector. The side of the current collector near the end plate is insulated from the end plate with hemp or fiber insulating material to prevent short circuit due to conduction through the connection of the male and female end plates via nuts.

[0074] The preferred anode material for the flow channel plate is titanium, nickel, stainless steel, or stainless steel plated with nickel. The preferred cathode material is graphite. The preferred flow channels are serpentine flow channels, grid flow channels, or parallel flow channels.

[0075] The preferred material for gaskets is polytetrafluoroethylene (PTFE) sheet, with silicone gaskets being the second choice.

[0076] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A hydrogen production membrane electrode for alkaline membrane electrolysis of water, comprising an alkaline membrane and an anode diffusion electrode and a cathode diffusion electrode separated by the alkaline membrane; the anode diffusion electrode is formed with an anode catalyst layer on one side of an anode porous diffusion layer by spraying an anode catalyst slurry, and the anode catalyst layer is close to the alkaline membrane; the cathode diffusion electrode is formed with a cathode catalyst layer on one side of a cathode porous diffusion layer by spraying a cathode catalyst slurry, and the cathode catalyst layer is close to the alkaline membrane; characterized in that: the anode catalyst slurry contains anode catalyst powder and alkaline ionomer containing cross-linking sites, and the cathode catalyst slurry contains cathode catalyst powder and alkaline ionomer containing cross-linking sites; the cross-linking sites of the alkaline ionomer are in-situ heat cross-linked by heating during the process of spraying to prepare the anode catalyst layer and the cathode catalyst layer, thereby fixing the anode catalyst layer and the cathode catalyst layer, and the alkaline ionomer is uniformly dispersed around the catalyst through the cross-linking fixation process; the alkaline ionomer containing cross-linking sites is a poly (fluorene-aryl piperidine-methyl styrene) polymer, and the alkaline membrane is made of a poly (fluorene-aryl piperidine) polymer. The temperature of the heat cross-linking is 60-120℃, and the heating time is 1-10 hours. The mass ratio of the anode catalyst powder to the alkaline ionomer containing cross-linking sites in the anode catalyst slurry is 1:0.05-0.3, and the mass ratio of the cathode catalyst powder to the alkaline ionomer containing cross-linking sites in the cathode catalyst slurry is 1:0.05-0.

3. The anode catalyst is at least one of NiFe catalyst, NiFeCo catalyst, CoFe catalyst, NiFeMo catalyst, FeCoMo catalyst, NiFeS catalyst, NiFeMn catalyst, NiFeCe catalyst, CoFeCr catalyst and CoCu catalyst; the cathode catalyst is at least one of Pt / C catalyst and PtRu / C catalyst; and the anode porous diffusion layer and the cathode porous diffusion layer are at least one of foamed nickel, foamed nickel-iron, foamed iron, foamed copper, foamed titanium, nickel felt, titanium felt, stainless steel felt, carbon paper and carbon cloth.

2. The alkaline membrane water electrolysis hydrogen-evolving membrane electrode according to claim 1, characterized in that: The method comprises the following steps:

3. The alkaline membrane water electrolysis hydrogen-evolving membrane electrode according to claim 1, characterized in that: Step 1, preparation of catalyst slurry 4. The alkaline membrane water electrolysis hydrogen-evolving membrane electrode according to claim 1, characterized by: adding the alkaline ionomer containing cross-linking sites into a solvent to obtain an alkaline ionomer solution; adding anode catalyst powder or cathode catalyst powder into deionized water, then adding isopropyl alcohol, and then adding the alkaline ionomer solution, and then placing the obtained mixed solution into an ultrasonic cell crusher for ultrasonic dispersion to obtain uniform anode catalyst slurry or cathode catalyst slurry; 5. A method for producing the hydrogen-evolving electrode of the alkaline membrane water electrolysis according to any one of claims 1 to 4, characterized by, Step 2, preparation of diffusion electrode ultrasonic spraying the anode catalyst slurry or the cathode catalyst slurry to one side of the anode porous diffusion layer or the cathode porous diffusion layer, and starting heating during the spraying process, and the cross-linking sites on the alkaline ionomer are cross-linked with each other after being heated to fix the catalyst, thereby obtaining an anode catalyst layer or a cathode catalyst layer with uniform and stable catalyst distribution, and obtaining an anode diffusion electrode or a cathode diffusion electrode; Step 3, preparation of hydrogen production membrane electrode for alkaline membrane electrolysis of water ​ ​ ​ The alkaline membrane water electrolysis hydrogen production membrane electrode is prepared by tightly attaching the anode diffusion electrode and the cathode diffusion electrode to two sides of the alkaline membrane respectively and then performing hot pressing by using a hot press.

6. The method of claim 5, wherein: immersing the alkaline membrane water electrolysis hydrogen production membrane electrode in a KOH solution to replace the alkaline ionomer in the alkaline membrane water electrolysis hydrogen production membrane electrode with the anion exchange groups of the alkaline membrane with OH - ions.

7. A hydrogen generation apparatus by alkaline membrane electrolysis of water, characterized by The alkaline membrane water electrolysis hydrogen production membrane electrode comprises the alkaline membrane water electrolysis hydrogen production membrane electrode according to any one of claims 1-4.

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