A hydrogen production diaphragm, its preparation method and application

Abstract

The application provides a hydrogen production diaphragm, a preparation method and application thereof, and the hydrogen production diaphragm comprises a body layer and a protective layer which is compounded on the surface of the body layer; the body layer is prepared from a polymer material, MOF nanoparticles and a reinforcing agent; or the body layer comprises a support formed by a polymer material, and a coating layer which is compounded on the surface of the support and comprises MOF nanoparticles and a reinforcing agent. The hydrogen production diaphragm can maintain voltage stability in a high-chloride-ion environment, improve electrolytic hydrogen production activity, prevent corrosion of the hydrogen production diaphragm by chloride ions, and increase the service life of the diaphragm.

Description

Technical Field

[0001] The present invention belongs to the field of hydrogen energy and seawater resource utilization, and particularly relates to a hydrogen production diaphragm and a preparation method and application thereof. Background Art

[0002] Alkaline water electrolysis hydrogen production offers the advantages of high hydrogen production capacity per unit and low cost, making it the current mainstream technology for large-scale green hydrogen production. However, this mainstream water electrolysis hydrogen production technology has high requirements for the quality of the raw water. Even in areas with abundant water resources, raw water often needs to be purified before use. The cumbersome process and high cost of water electrolysis hydrogen production have limited its development in different regions.

[0003] Seawater reserves are abundant on Earth, and offshore wind, solar, and wave energy resources are plentiful. Using seawater for direct hydrogen electrolysis is beneficial for the promotion of green hydrogen production. However, the high chloride ion content in seawater can corrode and damage the materials in hydrogen electrolysis systems. Furthermore, chloride ion oxidation can compete with the oxygen evolution reaction in hydrogen electrolysis. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a hydrogen production membrane and a preparation method and application thereof, which are beneficial to improving the activity of hydrogen production by electrolysis.

[0005] To achieve the above-mentioned purpose, the technical solution of the present invention is a hydrogen-producing membrane, comprising a main layer and a protective layer composited on the surface of the main layer; the main layer is made of a polymer material, MOF nanoparticles and a reinforcing agent; or the main layer comprises a support body formed of a polymer material, and a coating composited on the surface of the support body, and the coating comprises MOF nanoparticles and a reinforcing agent.

[0006] In one embodiment, the bulk layer of the hydrogen production membrane of the present invention is made of a polymer material, MOF nanoparticles and a reinforcing agent. The polymer material, MOF nanoparticles and reinforcing agent are mixed and dissolved, the mass ratio of the reinforcing agent to the MOF nanoparticles is 10:90 to 30:70, and the ratio of the sum of the mass of the reinforcing agent and the MOF nanoparticles to the mass of the polymer material is 5:95 to 10:90. The bulk layer is formed by a casting method, and the thickness of the bulk layer is 100 to 300 μm, preferably 50 to 200 μm. The casting method includes dissolving the polymer material, MOF nanoparticles and reinforcing agent in a solvent, scraping the solution onto a flat glass plate with a scraper, adjusting the thickness of the bulk layer by changing the height of the scraper relative to the glass plate, and volatilizing the solvent to obtain the bulk layer.

[0007] In another embodiment, the main layer of the hydrogen-producing membrane of the present invention includes a support formed of a polymer material, and a coating composited on the surface of the support, the coating including MOF nanoparticles and a reinforcing agent, the mass ratio of the reinforcing agent to the MOF nanoparticles is 10:90 to 30:70, the mass ratio of the coating to the support is 5:95 to 10:90, the thickness of the coating material is 5 to 30 μm, and the thickness of the main layer is 100 to 300 μm.

[0008] In one embodiment, the polymer material of the present invention is polyphenylene sulfide or polyetheretherketone, the reinforcing agent is polysulfone or polyvinylpyrrolidone, and the MOF nanoparticles are Zr6O4(OH)4-pyromellitic acid structure or MOF-801 structure.

[0009] The protective layer of the present invention is rich in OH - The protective layer is formed by an organic compound rich in sulfonic acid groups and an organic compound rich in sulfonic acid groups, and the thickness of the protective layer is 0.4 to 4 μm. In one embodiment, the protective layer of the present invention includes an alkaline modification layer composited on the main layer and a chloride ion blocking layer composited on the alkaline modification layer; or, the protective layer includes a chloride ion blocking layer composited on the main layer and an alkaline modification layer composited on the chloride ion blocking layer; the alkaline modification layer is rich in OH - The chloride ion barrier layer is an organic compound rich in sulfonic acid groups, with a thickness of 0.2 to 2 μm. In one embodiment, the organic compound rich in OH groups is - The organic compound containing the sulfonic acid group is an alcohol polymer, such as polyvinyl alcohol. The organic compound rich in sulfonic acid groups is Nafion or a sulfonated UIO-66 metal-organic framework. The protective layer of the present invention is formed on the surface of the bulk layer by spin coating and in-situ growth. The in-situ growth method specifically involves electrochemically or physically grafting, polymerizing, mono-loading, and depositing the protective layer onto the bulk layer to produce a composite material grown in-situ on the bulk layer.

[0010] In one embodiment, the bubble contact angle of the diaphragm is 153°, which can ensure that bubbles formed under high current density can be quickly detached.

[0011] The hydrogen-producing membrane provided by the present invention is modified with MOF particles having a regular pore structure, enhancing the membrane's gas repellency and promoting rapid gas evaporation at high current densities, thereby facilitating high current densities. The hydrogen-producing membrane can maintain voltage stability in high chloride ion environments, improve electrolytic hydrogen production activity, prevent chloride ion corrosion on the membrane, and extend the membrane's lifespan.

[0012] The present invention also provides a method for preparing a hydrogen production membrane, comprising the following steps:

[0013] Mixing polymer materials, MOF nanoparticles and reinforcing agents to obtain a bulk layer;

[0014] A protective layer is formed on the surface of the main layer to obtain a hydrogen production membrane.

[0015] The present invention mixes and dissolves polymer materials, MOF nanoparticles and reinforcing agents, adopts thermoforming and tape casting to form a bulk layer, and after obtaining the bulk layer, forms a protective layer on the surface of the bulk layer by spin coating and in-situ growth to obtain a hydrogen production diaphragm.

[0016] Alternatively, the present invention further provides a method for preparing a hydrogen production membrane, comprising the following steps:

[0017] The MOF nanoparticles and the reinforcing agent are compounded on a support formed by a polymer material to obtain a bulk layer;

[0018] A protective layer is formed on the surface of the main layer to obtain a hydrogen production membrane.

[0019] The present invention mixes and dissolves MOF nanoparticles and a reinforcing agent to obtain a coating material, and uses thermoforming and casting methods to compound the coating material on a support formed by a polymer material to form a body layer. After obtaining the body layer, a protective layer is formed on the surface of the body layer by spin coating and in-situ growth to obtain a hydrogen production diaphragm.

[0020] The present invention also provides an application of a hydrogen-producing membrane in a membrane electrode, a battery, or an electrolyzer. The hydrogen-producing membrane can be directly applied to the membrane electrode, the battery, or the electrolyzer, and the present invention does not limit this.

[0021] In one embodiment, the diaphragm of the present invention can be combined with a gas diffusion layer and a catalytic layer through conventional methods to form a membrane electrode, and then assembled with bipolar plates and other components to form an alkaline zero-gap electrolyzer for direct electrolysis of seawater to produce hydrogen, thereby realizing low-cost, flexible and efficient renewable energy green hydrogen production.

[0022] In one embodiment, the hydrogen production membrane described in the above technical solution is used as a membrane and assembled into a battery with an electrolyte and a working electrode.

[0023] In one embodiment, the hydrogen production diaphragm described in the above technical solution is used as a diaphragm, and a zero-gap electrolytic cell is prepared with an electrolyte, a cathode, and an anode to produce hydrogen by electrolysis.

[0024] The present invention provides a hydrogen-producing membrane, comprising a main layer and a protective layer composited on the surface of the main layer; the main layer is made of a polymer material, MOF nanoparticles and a reinforcing agent; or the main layer comprises a support formed of a polymer material and a coating composited on the surface of the support, the coating comprising MOF nanoparticles and a reinforcing agent. Experimental results show that the hydrogen-producing membrane of the present invention can maintain voltage stability in a high chloride ion environment, improve electrolytic hydrogen production activity, prevent chloride ion corrosion of the hydrogen-producing membrane, and increase the life of the membrane. The main layer of the hydrogen-producing membrane provided by the present invention is modified by adding MOF particles with a regular pore structure, replacing conventional hydrophilic inorganic nanoparticles, thereby enhancing the gas repellency of the membrane and promoting the rapid detachment of gas under high current density, thereby facilitating the realization of high current density. At the same time, the reinforcing agent forms hydrogen bonds with the metal elements of the MOF particles, thereby enhancing the stability of the membrane. The hydrogen-producing membrane of the present invention has a small thickness, can reduce the surface resistance, and improve the efficiency of electrolytic hydrogen production. The hydrogen production membrane obtained by the present invention is applied to an electrolyzer. The alkaline modification layer on the surface of the hydrogen production membrane can create a local alkaline environment on the surface of the hydrogen production membrane, which can effectively repel chloride ions, avoid the adverse effects of chloride ions on the anion conduction effect, and improve the selectivity of the oxygen evolution reaction in the presence of chloride ions in seawater. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0026] Figure 1 This is a schematic diagram of a hydrogen production membrane structure;

[0027] Figure 2 Schematic diagram of the alkaline zero-gap electrolyzer structure. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] The hydrogen production membrane, its preparation method and application are further described below with reference to the embodiments.

[0030] Example 1:

[0031] The preparation process of the hydrogen production membrane specifically includes the following steps:

[0032] (1) Formation of the bulk layer: Polysulfone and MOF nanoparticles (Zr6O4(OH)4-trimethylbenzenecarboxylic acid repeating structure with a frame window size of approximately 1 nm, synthesized by solvothermal, hydrothermal, electrochemical, physical grinding, etc., with a particle size of 30-50 nm) in a mass ratio of 15:85 were dispersed in DMF (N,N-dimethylformamide) to form a uniform mixture. The mass fraction of polysulfone and MOF particles in the DMF mixture was 30%. The mixture was cast into a film on a glass plate. During casting, a 280 μm polyphenylene sulfide sheet was placed in the mixture as a support. By changing the height of the scraper relative to the glass plate, a film with a thickness of 300 μm was obtained. The obtained film was dried in a 60°C oven for 6 h and then dried in a 100°C vacuum oven for 12 h. It was peeled off from the glass plate and washed three times with excess deionized water to obtain a bulk layer with a thickness of 300 μm. It was stored in fresh deionized water before use.

[0033] (2) Forming an alkaline modification layer: PVA (polyvinyl alcohol) was dissolved in a DMF solution to obtain a 10% by mass PVA solution. The PVA solution was evenly spin-coated on the surface of the bulk layer at a spin-coating speed of 200 rpm for 0.5 min, and then vacuum-dried at 50°C for 12 h to form an alkaline modification layer with a thickness of 0.2 μm on the surface of the bulk layer.

[0034] (3) Forming a chloride ion barrier layer: Nafion (perfluorosulfonic acid ion membrane) was dissolved in DMF to obtain a Nafion solution with a mass fraction of 30%. The Nafion solution was evenly spin-coated on the surface of the alkaline modified layer at a spin-coating speed of 200 rpm for 3 minutes, and then vacuum-dried at 50°C for 12 hours to form a chloride ion barrier layer with a thickness of 2 μm on the surface of the alkaline modified layer to obtain a hydrogen production membrane. The bubble contact angle of the membrane was measured by the bubble capture method and was 153°, which can ensure the rapid detachment of bubbles formed under high current density.

[0035] See also Figure 1 , Figure 1 This is a schematic diagram of the structure of a hydrogen production membrane. The hydrogen production membrane of the present invention includes a body layer 1, an alkaline modification layer 2 located on the surface of the body layer 1, and a chloride ion barrier layer 3 located on the surface of the alkaline modification layer 2.

[0036] Example 2:

[0037] The hydrogen production membrane obtained in Example 1 is designated as Hydrogen Production Membrane 1. A hydrogen production membrane was prepared according to the method of Example 1, except that the alkaline modification layer was not prepared, to obtain Hydrogen Production Membrane 2. A hydrogen production membrane was prepared according to the method of Example 1, except that the alkaline modification layer and the chloride ion barrier layer were not prepared, to obtain Hydrogen Production Membrane 3. A pure polyphenylene sulfide membrane was designated as Hydrogen Production Membrane 4.

[0038] See also Figure 2 , Figure 2 The schematic diagram of the alkaline zero-gap electrolyzer structure includes a cathode, a diaphragm, and an anode. Hydrogen production diaphragms 1 to 4 are used, seawater is used as the electrolyte, and the anode catalyst is iridium oxide with a loading of 2 mg / cm 2 The cathode catalyst is 20% Pt / C with a loading of 2 mg / cm 2 ; The current density is 10mA / cm 2 , electrolysis was performed to produce hydrogen. After 6 hours of electrolysis, the electrolysis hydrogen production effects of different hydrogen production membranes were compared. The results are shown in Table 1. Table 1 shows the hydrogen production effects of seawater electrolysis.

[0039] Table 1 Results of hydrogen production by seawater electrolysis

[0040] Hydrogen production membrane 1 2 3 4 Chamber voltage (V) 1.68V 1.75V 1.82V 1.93V

[0041] Experimental results show that the presence of a chloride ion barrier layer and an alkaline modification layer lowers the cell voltage, which is beneficial for enhancing the activity of hydrogen production from water electrolysis. Furthermore, the presence of MOF particles and structural reinforcement significantly improves the hydrogen production activity of the hydrogen-producing membrane described in this invention.

[0042] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A hydrogen production membrane, characterized in that It comprises a main body layer and a protective layer compounded on the surface of the main body layer; The bulk layer is made of polymer materials, MOF nanoparticles and reinforcing agents; Alternatively, the bulk layer includes a support formed of a polymer material and a coating composited on the surface of the support, wherein the coating includes MOF nanoparticles and a reinforcing agent; The protective layer includes an alkaline modification layer compounded on the body layer and a chloride ion blocking layer compounded on the alkaline modification layer; Alternatively, the protective layer includes a chloride ion blocking layer composited on the bulk layer and an alkaline modification layer composited on the chloride ion blocking layer; The basic modified layer is rich in OH - The chloride ion blocking layer is an organic compound rich in sulfonic acid groups.

2. The hydrogen production membrane according to claim 1, characterized in that The mass ratio of the reinforcing agent to the MOF nanoparticles is 10:90 to 30:70, and the ratio of the sum of the mass of the reinforcing agent and the MOF nanoparticles to the mass of the polymer material is 5:95 to 10:

90.

3. The hydrogen production membrane according to claim 1, characterized in that: The polymer material is polyphenylene sulfide or polyetheretherketone, and the reinforcing agent is polysulfone or polyvinylpyrrolidone.

4. The hydrogen production membrane according to claim 1, characterized in that: The OH-rich - The organic compound rich in sulfonic acid groups is an alcohol polymer; the organic compound rich in sulfonic acid groups is Nafion or a sulfonated UIO-66 metal organic framework material.

5. The hydrogen production membrane according to claim 1, characterized in that: The thickness of the main layer is 100-300 μm, and the thickness of the protective layer is 0.4-4 μm.

6. A method for preparing a hydrogen production membrane, characterized in that: The following steps are involved: Mixing polymer materials, MOF nanoparticles and reinforcing agents to obtain a bulk layer; forming a protective layer on the surface of the bulk layer to obtain a hydrogen production membrane; The protective layer includes an alkaline modification layer compounded on the body layer and a chloride ion blocking layer compounded on the alkaline modification layer; Alternatively, the protective layer includes a chloride ion blocking layer composited on the bulk layer and an alkaline modification layer composited on the chloride ion blocking layer; The basic modified layer is rich in OH - The chloride ion blocking layer is an organic compound rich in sulfonic acid groups.

7. A method for preparing a hydrogen production membrane, characterized in that: The following steps are involved: The MOF nanoparticles and the reinforcing agent are compounded on a support formed by a polymer material to obtain a bulk layer; forming a protective layer on the surface of the bulk layer to obtain a hydrogen production membrane; The protective layer includes an alkaline modification layer compounded on the body layer and a chloride ion blocking layer compounded on the alkaline modification layer; Alternatively, the protective layer includes a chloride ion blocking layer composited on the bulk layer and an alkaline modification layer composited on the chloride ion blocking layer; The basic modified layer is rich in OH - The chloride ion blocking layer is an organic compound rich in sulfonic acid groups.

8. Use of the hydrogen production membrane according to any one of claims 1 to 5 in a membrane electrode, a battery or an electrolyzer.

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