Dehydrogenation layer for PEM electrolyzed water membrane electrode and preparation method and application thereof

Abstract

The invention provides a hydrogen elimination layer for a PEM electrolyzed water membrane electrode and a preparation method and application of the hydrogen elimination layer. The hydrogen elimination layer for the PEM electrolytic water membrane electrode is prepared from hydrogen elimination layer slurry, the hydrogen elimination layer slurry comprises the following components: a hydrogen elimination catalyst, organic alcohol, an ionomer and ultrapure water, the solid content in the hydrogen elimination layer slurry is 0.5-3%, the mass ratio of the ionomer to the hydrogen elimination catalyst is 0.1-1.5, and the mass content of the organic alcohol is 20-50%. The hydrogen elimination layer is directly integrated on the porous transport layer (PTL), and the structure of the membrane electrode does not need to be changed; the hydrogen elimination layer is integrated on the PTL to increase the pore tortuosity and slow down the hydrogen diffusion rate, and the microporous structure composites / adsorbs hydrogen while slowing down hydrogen diffusion; the hydrogen elimination layer can effectively relieve the cathode hydrogen permeation phenomenon, reduces the potential safety hazard of the operation of the electrolytic cell, and has no negative influence on the performance of the electrolytic cell.

Description

Technical Field

[0001] The present invention belongs to the field of proton exchange membrane water electrolysis, and in particular relates to a hydrogen removal layer for a PEM water electrolysis membrane electrode, and a preparation method and application thereof. Background Art

[0002] As a clean energy carrier, hydrogen is widely used in energy storage, transportation, ammonia synthesis, and other high-value chemicals. Proton exchange membrane electrolysis (PEM) splits water into oxygen and hydrogen through an electrochemical reaction within the electrolyzer. It offers high energy efficiency, fast response, and a clean, environmentally friendly design. It can effectively handle dynamic energy inputs, from low loads (0-10%) to overloads (up to 150%), making it highly effective for renewable energy-driven hydrogen production.

[0003] During electrolyzer operation, ohmic losses due to membrane resistance are a significant factor in voltage loss. The use of a membrane can minimize these losses. Proton exchange membrane (PEM) electrolyzers typically operate at high cathode (H2 outlet) pressure while maintaining atmospheric pressure on the anode side, saving the cost of mechanical H2 compression. However, the combination of a membrane and high differential pressure significantly increases the risk of hydrogen permeation. Hydrogen permeates through the membrane from the cathode to the anode and mixes with oxygen produced at the anode. Especially at low current densities, the hydrogen concentration in the oxygen is more likely to reach the lower explosion limit of hydrogen (4%), posing a significant safety hazard. Furthermore, permeated hydrogen radicals (H·) react with oxygen at the anode / PEM interface to form free radical intermediates, which attack the anode membrane and ionomer, accelerating electrolyzer degradation.

[0004] Regulating the electrolyzer operating conditions can keep the hydrogen concentration in the anode oxygen within a safe range, but this sacrifices the PEMWE's adaptability to fluctuations. On the other hand, increasing the membrane thickness can effectively reduce hydrogen permeation, but the increase in ohmic resistance will reduce electrolysis performance. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art by providing a hydrogen-scavenging layer for PEM water electrolysis membrane electrodes, as well as its preparation method and application. The hydrogen-scavenging layer is directly integrated onto the porous transport layer (PTL), eliminating the need to modify the membrane electrode structure. The integration of the hydrogen-scavenging layer onto the PTL increases pore tortuosity, slowing hydrogen diffusion. The microporous structure simultaneously slows hydrogen diffusion and allows for the recombination / absorption of hydrogen. The hydrogen-scavenging layer effectively mitigates cathode hydrogen permeation, reducing safety hazards associated with electrolyzer operation without negatively impacting electrolyzer performance.

[0006] To achieve the above technical objectives, the technical solutions adopted in the embodiments of the present invention are: In a first aspect, an embodiment of the present invention provides a hydrogen removal layer for a PEM water electrolysis membrane electrode, wherein the hydrogen removal layer is made of a hydrogen removal layer slurry, and the hydrogen removal layer slurry includes the following components: a hydrogen removal catalyst, an organic alcohol, an ionomer, and ultrapure water. The solid content of the hydrogen removal layer slurry is 0.5%-3%, the mass ratio of the ionomer to the hydrogen removal catalyst is 0.1-1.5, and the mass content of the organic alcohol is 20-50%.

[0007] Furthermore, the hydrogen removal catalyst is one of palladium black, palladium / carbon and platinum palladium black.

[0008] Furthermore, the organic alcohol is one of ethanol, n-propanol and isopropanol.

[0009] Furthermore, the ionomer is a perfluorosulfonic acid resin solution, and the mass ratio of the perfluorosulfonic acid resin to the catalyst in the perfluorosulfonic acid resin solution is 0.1-1.5.

[0010] In a second aspect, an embodiment of the present invention provides a method for preparing a hydrogen removal layer for a PEM water electrolysis membrane electrode according to the first aspect, comprising the following steps: Step S1: immerse the porous transmission layer PTL in a cleaning agent and perform ultrasonic cleaning to remove surface organic matter and impurities, and then dry it for later use; Step S2: mixing the required components according to the composition of the hydrogen removal catalyst slurry; Step S3, using an ultrasonic cell disruptor for ultrasonic treatment to obtain a hydrogen removal catalyst slurry; Step S4: using an ultrasonic sprayer to evenly spray the hydrogen removal catalyst slurry onto the porous transport layer PTL, heating and drying, to obtain a porous transport layer PTL containing a hydrogen removal layer; Step S5: Using a flat-plate hot press machine to hot-press and solidify the PTL obtained in step S4 to ensure that the hydrogen removal layer is tightly bonded to the PTL.

[0011] Furthermore, in step S1, the PTL is one of titanium felt and sintered titanium plate, has a porosity of 50%-80%, and the cleaning agent is one or more of acetone, ethanol, and ultrapure water.

[0012] Furthermore, in step S3, the ultrasonic power during the ultrasonic treatment is 10W-1000W, and the ultrasonic time is 10-200min.

[0013] Furthermore, in step S4, the drying temperature is 70-95°C, and the loading amount of the noble metal is 0.05-0.5 mg·cm -2 .

[0014] Furthermore, in step S5, the hot pressing temperature is 110-150° C., the hot pressing pressure is 1-3 MPa, and the hot pressing time is 1-5 min.

[0015] In a third aspect, an embodiment of the present invention provides an application of the hydrogen removal layer described in the first aspect, wherein the hydrogen removal layer is directly integrated on the anode PTL of the PEM water electrolysis membrane electrode.

[0016] The technical solution provided by the embodiment of the present invention has the following beneficial effects: 1. Improved security Traditional problem: H2 diffuses back to the anode from the cathode side of the electrode without a hydrogen-absorbing membrane layer. Under high-pressure and dynamic working conditions, H2 / O2 mixed explosive gas is easily generated and can only be diluted by exhaust gas from the system.

[0017] Improvements of the present invention: The Pd-containing catalyst catalyzes the real-time recombination of H₂ and O₂ (2H₂ + O₂ → 2H₂O) on the anode side. Furthermore, the Pd actively absorbs hydrogen and converts it into palladium hydride, effectively reducing the hydrogen content in the anode oxygen. The microporous structure of the hydrogen-scavenging layer on the PTL slows hydrogen diffusion while simultaneously recombine / absorbing hydrogen, effectively improving system safety.

[0018] 2. Optimize water and gas transmission Traditional problems: PTL (such as titanium sintered felt) has a large pore size, which leads to insufficient liquid water supply at high current density, resulting in membrane dehydration; oxygen bubbles are retained, causing concentration polarization.

[0019] Improvements of the present invention: The presence of the hydrogen-absorbing layer on the PTL can refine the bubble size, accelerate the discharge of oxygen, and enhance the reverse osmosis of water through capillary action.

[0020] 3. Reduce interface contact resistance Traditional problems: Titanium-based PTL is prone to forming a TiO2 passivation film under high anode potential and acidic environment; the PTL surface is highly rough and the contact with the catalytic layer is not close, resulting in increased contact resistance.

[0021] Improvement of the present invention: The hydrogen removal catalyst is covered on the surface of the PTL to effectively inhibit the passivation of the PTL, enhance electronic conduction, and reduce interface resistance.

[0022] 4. Good process compatibility The hydrogen removal layer can be directly coated on commercial PTL (such as titanium sintered felt) without changing the MEA structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The electrolytic cell performance diagram of the membrane electrode prepared in Examples 1-3 and Comparative Example 1.

[0024] Figure 2 The hydrogen content in oxygen at different current densities when the membrane electrodes prepared in Examples 1-3 and Comparative Example 1 are used. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] Example 1 A method for preparing a hydrogen removal layer for a PEM water electrolysis membrane electrode comprises the following steps: Step S1: immersing the PTL in a mixed solution of acetone: ethanol: ultrapure water = 1:1:1 (volume ratio). The PTL uses titanium felt with a porosity of 70%, ultrasonically cleaning it to remove surface organic matter and impurities, and drying it for later use. Step S2, weighing palladium black catalyst, ultrapure water, n-propanol and Nafion D2020 perfluorosulfonic acid resin solution to prepare a catalyst slurry with a solid content of 1%, wherein the mass ratio of Nafion D2020 perfluorosulfonic acid resin to palladium black catalyst is 0.5, and the mass content of n-propanol in the solution is 40%; Step S3: After mixing the above components, use an ultrasonic cell disruptor to disperse them at an ultrasonic power of 100 W, an ultrasonic time of 60 minutes, and an ultrasonic temperature of 10° C. to obtain a catalyst slurry; Step S4: Use an ultrasonic sprayer to evenly spray the dehydrogenation catalyst slurry onto the PTL, dry it at 85°C, and control the palladium loading to 0.2 mg cm -2 , obtaining a PTL containing a hydrogen-absorption layer; Step S5: Use a flat hot press to hot-press and solidify the PTL containing the hydrogen removal layer obtained in step S4 at a temperature of 130° C., a pressure of 2 MPa, and a time of 3 min to ensure that the hydrogen removal layer is tightly bonded to the PTL.

[0027] The cathode and anode catalyst layers of the PTFE membrane were transferred to the Nafion 115 proton exchange membrane. The anode Ir loading was 1.0 mg cm -2 , the cathode Pt loading is 0.3 mg·cm -2 The anode side is laminated with a PTL containing a hydrogen removal layer, and the cathode side is laminated with a blank PTL to obtain a "five-in-one" PEM water electrolysis membrane electrode assembly with a hydrogen removal layer.

[0028] Example 2 A method for preparing a hydrogen removal layer for a PEM water electrolysis membrane electrode comprises the following steps: Step S1: immersing the PTL in a mixed solution of acetone: ethanol: ultrapure water = 1:1:1 (volume ratio). The PTL uses titanium felt with a porosity of 70%, ultrasonically cleaning it to remove surface organic matter and impurities, and drying it for later use. Step S2: weighing a palladium / carbon catalyst, ultrapure water, n-propanol, and Nafion D2020 perfluorosulfonic acid resin solution to prepare a catalyst slurry with a solid content of 1%, wherein the mass ratio of Nafion D2020 perfluorosulfonic acid resin to palladium / carbon catalyst is 0.8, and the mass content of n-propanol in the solution is 40%; Step S3: After mixing the above components, use an ultrasonic cell disruptor to disperse them at an ultrasonic power of 100 W, an ultrasonic time of 60 minutes, and an ultrasonic temperature of 10° C. to obtain a catalyst slurry; Step S4: Use an ultrasonic sprayer to evenly spray the dehydrogenation catalyst slurry onto the PTL, dry it at 85°C, and control the palladium loading to 0.2 mg cm -2 , obtaining a PTL containing a hydrogen-absorption layer; Step S5: Use a flat hot press to hot-press and solidify the PTL obtained in step S4 at a temperature of 130° C., a pressure of 2 MPa, and a time of 3 min to ensure that the hydrogen removal layer is tightly bonded to the PTL.

[0029] The cathode and anode catalyst layers of the PTFE membrane were transferred to the Nafion 115 proton exchange membrane. The anode Ir loading was 1.0 mg cm -2 , the cathode Pt loading is 0.3 mg·cm -2 The anode side is laminated with a PTL containing a hydrogen removal layer, and the cathode side is laminated with a blank PTL to obtain a "five-in-one" PEM water electrolysis membrane electrode assembly with a hydrogen removal layer.

[0030] Example 3 A method for preparing a hydrogen removal layer for a PEM water electrolysis membrane electrode comprises the following steps: Step S1: immersing the PTL in a mixed solution of acetone: ethanol: ultrapure water = 1:1:1 (volume ratio). The PTL uses titanium felt with a porosity of 70%, ultrasonically cleaning it to remove surface organic matter and impurities, and drying it for later use. Step S2: Weigh platinum palladium black (platinum to palladium atomic ratio of 1:1) catalyst, ultrapure water, n-propanol, and Nafion D2020 perfluorosulfonic acid resin solution to prepare a catalyst slurry with a solid content of 1%, wherein the mass ratio of Nafion D2020 perfluorosulfonic acid resin to platinum palladium black catalyst is 0.5, and the mass content of n-propanol in the solution is 40%; Step S3: After mixing the above components, use an ultrasonic cell disruptor to disperse them at an ultrasonic power of 100 W, an ultrasonic time of 60 minutes, and an ultrasonic temperature of 10° C. to obtain a catalyst slurry; Step S4: Use an ultrasonic sprayer to evenly spray the dehydrogenation catalyst slurry onto the PTL, dry it at 85°C, and control the total loading of precious metals platinum and palladium to be 0.2 mg cm -2, obtaining a PTL containing a hydrogen-absorption layer; Step S5: Use a flat hot press to hot-press and solidify the PTL obtained in step S4 at a temperature of 130° C., a pressure of 2 MPa, and a time of 3 min to ensure that the hydrogen removal layer is tightly bonded to the PTL.

[0031] The cathode and anode catalyst layers of the PTFE membrane were transferred to the Nafion 115 proton exchange membrane. The anode Ir loading was 1.0 mg cm -2 , the cathode Pt loading is 0.3 mg·cm -2 The anode side is laminated with a PTL containing a hydrogen removal layer, and the cathode side is laminated with a blank PTL to obtain a "five-in-one" PEM water electrolysis membrane electrode assembly with a hydrogen removal layer.

[0032] Comparative Example 1 The cathode and anode catalyst layers of the PTFE membrane were transferred to the Nafion 115 proton exchange membrane. The anode Ir loading was 1.0 mg cm -2 , the cathode Pt loading is 0.3 mg·cm -2 . Blank PTL is bonded to the anode and cathode sides to form a "five-in-one" PEM water electrolysis membrane electrode assembly.

[0033] The membrane electrodes prepared in Examples 1-3 and Comparative Example 1 were tested for water electrolysis performance at 80°C. The test results are as follows: Figure 1 As shown. Figure 1 It can be seen that the performance of Comparative Example 1 and Examples 1-3 is not much different, which indicates that the presence of the hydrogen removal layer has no negative impact on the membrane electrode performance. The presence of the hydrogen removal layer does not show an increase in proton transport resistance or interface resistance. At the same time, the accumulation of hydrogen bubbles is reduced by optimizing the gas diffusion path.

[0034] When the cathode pressure is 3 MPa, the hydrogen content in oxygen at different current densities of the membrane electrodes prepared in Examples 1-3 and Comparative Example 1 is as follows: Figure 2 As shown. 0.5 A·cm -2 The hydrogen content in oxygen in Comparative Example 1, Example 1, Example 2, and Example 3 was 1.66%, 1.04%, 1.33%, and 1.07%, respectively. This demonstrates that the integration of a hydrogen removal layer containing palladium black or a palladium composite catalyst on the anode PTL side exhibits a significant hydrogen removal effect, effectively reducing the hydrogen content in the anode-side oxygen. The dual hydrogen removal effect of the hydrogen removal layer avoids the risk of hydrogen-oxygen mixture explosion, especially at high voltage and high current density, reducing the safety risks of electrolyzer operation.

[0035] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A hydrogen removal layer for a PEM water electrolysis membrane electrode, characterized in that: The dehydrogenation layer is made of dehydrogenation layer slurry, which includes the following components: dehydrogenation catalyst, organic alcohol, ionomer and ultrapure water. The solid content of the dehydrogenation layer slurry is 0.5%-3%, the mass ratio of the ionomer to the dehydrogenation catalyst is 0.1-1.5, and the mass content of the organic alcohol is 20-50%.

2. The hydrogen removal layer for PEM water electrolysis membrane electrode according to claim 1, characterized in that: The hydrogen removal catalyst is one of palladium black, palladium / carbon and platinum palladium black.

3. The hydrogen removal layer for PEM water electrolysis membrane electrode according to claim 1, characterized in that: The organic alcohol is one of ethanol, n-propanol and isopropanol.

4. The hydrogen removal layer for PEM water electrolysis membrane electrode according to claim 1, characterized in that: The ionomer is a perfluorosulfonic acid resin solution, and the mass ratio of the perfluorosulfonic acid resin to the catalyst in the perfluorosulfonic acid resin solution is 0.1-1.

5.

5. The method for preparing the hydrogen-scavenging layer for the PEM water electrolysis membrane electrode according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step S1: immerse the porous transmission layer PTL in a cleaning agent and perform ultrasonic cleaning to remove surface organic matter and impurities, and then dry it for later use; Step S2: mixing the required components according to the composition of the hydrogen removal catalyst slurry; Step S3, using an ultrasonic cell disruptor for ultrasonic treatment to obtain a hydrogen removal catalyst slurry; Step S4: using an ultrasonic sprayer to evenly spray the hydrogen removal catalyst slurry onto the porous transport layer PTL, heating and drying, to obtain a porous transport layer PTL containing a hydrogen removal layer; Step S5: Using a flat-plate hot press machine to hot-press and solidify the PTL obtained in step S4 to ensure that the hydrogen removal layer is tightly bonded to the PTL.

6. The method for preparing a hydrogen-scavenging layer for a PEM water electrolysis membrane electrode according to claim 5, characterized in that: In step S1, the PTL is one of titanium felt and sintered titanium plate, with a porosity of 50%-80%, and the cleaning agent is one or more of acetone, ethanol, and ultrapure water.

7. The method for preparing a hydrogen-scavenging layer for a PEM water electrolysis membrane electrode according to claim 5, characterized in that: In step S3, the ultrasonic power during the ultrasonic treatment is 10-1000 W, and the ultrasonic time is 10-200 min.

8. The method for preparing a hydrogen-scavenging layer for a PEM water electrolysis membrane electrode according to claim 5, characterized in that: In step S4, the drying temperature is 70-95°C, and the loading amount of the precious metal on the PTL is 0.05-0.5 mg·cm -2 .

9. The method for preparing a hydrogen-scavenging layer for a PEM water electrolysis membrane electrode according to claim 5, wherein: In step S5, the hot pressing temperature is 110-150° C., the hot pressing pressure is 1-3 MPa, and the hot pressing time is 1-5 min.

10. The use of the hydrogen removal layer according to claim 1, characterized in that: The hydrogen removal layer is directly integrated on the anode PTL of the PEM water electrolysis membrane electrode.

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