Alkaline electrolytic water hydrogen production diaphragm based on zirconium oxide modification and preparation method thereof

Abstract

The invention provides an alkaline electrolytic water hydrogen production diaphragm based on zirconium oxide modification, the alkaline electrolytic water hydrogen production diaphragm comprises a support layer and a hydrophilic modified coating on the support layer, the hydrophilic modified coating is obtained by coating the support layer with a casting liquid prepared from modified zirconium oxide particles, a film-forming polymer and an organic solvent and then carrying out non-solvent induced phase inversion, the modified zirconium oxide particles are prepared by adding micron-sized zirconium oxide and alkali liquor into a ball mill for ball milling, and the particle size of the zirconium oxide subjected to ball milling treatment is 20-100nm. According to the method, the structure of the micron-sized zirconium oxide particles is regulated and controlled by combining a ball milling-alkali etching synchronous process. Through combination of ball milling treatment and alkali etching treatment, the dispersion degree and the reaction opportunity of the zirconium oxide powder can be effectively improved, and the efficiency of the etching process is remarkably improved. The obtained modified zirconium oxide particles endow the diaphragm with excellent hydrophilicity, alkali resistance and OH <-> ion conduction performance, and the diaphragm has excellent performance when being used as an alkaline electrolytic water hydrogen production diaphragm.

Description

Technical Field

[0001] The present invention belongs to the technical field of diaphragm materials for hydrogen production by electrolysis of water, and particularly relates to an alkaline electrolytic water hydrogen production diaphragm modified based on zirconia and a preparation method thereof. Background Art

[0002] Alkaline electrolytic water hydrogen production is one of the most mature and commercially available electrolytic water hydrogen production technologies at present. Its core is to decompose water into hydrogen and oxygen by alkaline electrolyte under the action of direct current. In the alkaline electrolytic water hydrogen production system, the diaphragm plays an important role in separating hydrogen and oxygen gases and maintaining the electrolyte circulation, and its performance directly affects the electrolysis efficiency and the long-term stability of the equipment.

[0003] Traditional asbestos diaphragms have been gradually phased out due to carcinogenicity and easy degradation problems. New composite diaphragms (such as polysulfone and polyphenylene sulfide-based materials) and inorganic-organic composite membranes (such as ZrO2 / PPS) have become research hotspots, aiming to improve ion conductivity, mechanical strength and corrosion resistance. At present, the resistance of domestic diaphragms is still generally higher than that of imported diaphragms. The Zirfon membrane represented by Agfa Company in Belgium has a lower resistivity, but its price is much higher than that of domestic membranes. Polyphenylene sulfide has good chemical stability, high temperature resistance and high alkali resistance, but the polyphenylene sulfide diaphragm has strong hydrophobicity, and its performance is limited when applied to electrolytic water diaphragms.

[0004] CN118932411A discloses a preparation method of a composite diaphragm for electrolytic water hydrogen production, comprising the following steps: 1) mixing zirconia powder with an alkaline solution, and heating and modifying to obtain modified zirconia; the specific surface area of the zirconia powder is 10-50 m 2 / g, and the average particle size D50 is 0.5-3.0 μm; the modified zirconia obtained after heating and modification has a surface hydroxyl density of (1-6) n OH / nm 2 ; 2) mixing a polymer resin, the modified zirconia and an organic solvent, and stirring evenly to obtain a slurry; 3) coating the slurry on both sides of a polyphenylene sulfide mesh, and obtaining the composite diaphragm for electrolytic water hydrogen production after phase inversion. After modification, the surface hydroxyl density of zirconia is increased. As a hydrophilic inorganic particle material, it is then blended with a polymer resin such as polysulfone and coated on polyphenylene sulfide to obtain a composite diaphragm. However, in this patent, the modification process of zirconia relies on long-term treatment with high-temperature and high-concentration alkaline solutions, which consumes a large amount of energy, and does not involve effective control of the particle size of zirconia, easily leading to particle agglomeration and affecting the dispersion uniformity and interface bonding effect.

[0005] CN117431586A discloses a modified nano-composite diaphragm for highly hydrophilic alkaline electrolyzed water. The porous support layer is treated by plasma, and the inorganic nanoparticles are modified. Specifically, the inorganic nanoparticles are added to a modified solvent containing a modifier and stirred at a certain stirring speed. During the process, it is heated to a certain temperature, refluxed, and then centrifuged, ultrasonically treated, filtered, repeatedly washed, and dried at a constant temperature for a period of time to obtain modified inorganic nanoparticles. The modifier is selected from one of polyethylene glycol, diethanolamine, acrylic acid, adipic acid, and aminopropyltriethoxysilane. The binding stability of the organic modifier used in this patent in a strong alkaline environment has certain uncertainties, which may affect the maintenance of the hydrophilic effect; the method of treating the support layer by plasma has a high cost; at the same time, there are many steps in the particle modification, involving operations such as ultrasonic treatment, filtration, and multiple washings, and the process is relatively complex, which is not conducive to industrial scale application.

[0006] CN118996524A discloses a preparation method of a high-performance composite diaphragm for an alkali water tank. In this patent, hydrophilic inorganic nanoparticles and a second type of functional inorganic nanofiller are compounded and mixed, and made into a casting solution with a thermoplastic resin. The casting solution is coated on the support layer and then a diaphragm is formed through a phase inversion process. The hydrophilic inorganic nanoparticles are selected from zirconia, titanium oxide, cerium dioxide, etc.; the second type of functional inorganic nanofiller is selected from at least one of metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and layered double hydroxides (LDHs). The second type of functional inorganic nanofiller plays a hydrophilic role, which is beneficial to the conduction of OH - ions; it can also construct a hydrogen bond network in the membrane and introduce a new OH - ion conduction mechanism, reducing the influence of the diaphragm pore structure on the surface resistance. In addition, the second type of functional inorganic nanofiller can controllably adjust the diaphragm pore structure, further improving the airtightness of the composite diaphragm. However, this patent introduces materials such as MOFs and COFs, which have functions but are difficult to prepare and have a high cost, and their chemical stability under strong alkaline conditions is limited, and there is a potential risk of material degradation in long-term application in an alkaline electrolysis system.

[0007] CN117947462A discloses an alkaline water electrolysis composite diaphragm. In order to improve the hydrophilicity of the diaphragm, this patent modifies polyphenylene sulfide with dopamine to obtain a polydopamine-modified polyphenylene sulfide network to improve the hydrophilicity of the diaphragm. However, the polydopamine coating has chemical stability problems in strong alkaline environments such as 30wt% KOH and is prone to degradation or peeling; in addition, the chemical inertness and poor interfacial adhesion performance of the polyphenylene sulfide network itself also limit the long-term stability and practical application effect of this diaphragm structure.

[0008] CN117512693A discloses a composite diaphragm for alkaline water electrolysis hydrogen production with superhydrophilic surface and integral cross-linked structure. Both surfaces of the polymer porous membrane are coated with a hydrophilic polymer coating with a thickness of 3-11 μm; the polymer porous membrane is composed of three substances: a polymer film-forming substance, nanoscale cellulose or its derivatives, and hydrophilic inorganic nanoparticles; the hydrophilic polymer is at least one of cellulose nanocrystals, nanocellulose, and cellulose nanofibers. However, the cellulose-based substances introduced in this patent have high costs and insufficient chemical stability in strong alkaline environments, affecting the large-scale application and long-term service performance of the membrane.

[0009] The above-mentioned prior art modifies the composite diaphragm through different technical means, especially modifying the hydrophilic inorganic particles to improve the performance of the composite diaphragm. However, there are certain deficiencies in terms of particle stability, persistence of modification effect, or controllability of the preparation process, making it difficult to balance the unity of high hydrophilicity, high ionic conductivity, and long-term alkali resistance stability. Moreover, some technical routes still have certain complexity and cost barriers in industrial applications.

[0010] CN118932411A discloses a preparation method of a composite diaphragm for electrolytic water hydrogen production, including the following steps: 1) Mix zirconia powder with an alkaline solution, and obtain modified zirconia after heating modification; the specific surface area of the zirconia powder is 10-50 m 2 / g, and the average particle size D50 is 0.5-3.0 μm; the surface hydroxyl density of the modified zirconia obtained after heating modification is (1-6) nOH / nm 2 ; 2) Mix a polymer resin, modified zirconia, and an organic solvent, and stir evenly to obtain a slurry; 3) Coat the slurry on both sides of a polyphenylene sulfide mesh, and obtain the composite diaphragm for electrolytic water hydrogen production after phase inversion. This patent uses alkali to treat zirconia to modify -OH groups on the zirconia surface to improve hydrophilicity. However, the alkali treatment efficiency of zirconia in this patent is low and the effect is not good. It still takes more than 3 hours even under the condition of heating at 80-90 °C, and the effect of the finally obtained diaphragm is not ideal. Summary of the Invention

[0011] In order to overcome the defects of poor diaphragm performance caused by insufficient hydrophilicity of inorganic particles, easy agglomeration, poor ionic conductivity of the diaphragm, and insufficient interfacial wettability in the alkaline electrolytic water hydrogen production diaphragm in the prior art, the present invention proposes an alkaline electrolytic water hydrogen production diaphragm and its preparation method, by coating a hydrophilic zirconia particle and a polysulfone organic-inorganic composite layer on a support layer; the etched zirconia particles provided by the present invention have higher hydrophilicity and ionic conduction ability compared with the zirconia particles in traditional diaphragm materials, improving the performance of the alkaline electrolytic water hydrogen production diaphragm. Specifically, the present invention provides the following technical content to achieve the above purpose:

[0012] An alkaline electrolyzed water hydrogen production diaphragm based on zirconia modification, comprising a support layer and a hydrophilic modification coating on the support layer. The hydrophilic modification coating is obtained by non-solvent induced phase inversion after a casting solution prepared from modified zirconia particles, film-forming polymers, and organic solvents is coated on the support layer. The modified zirconia particles are obtained by ball milling micron-sized zirconia and an alkali solution in a ball mill, and the particle size of the zirconia after ball milling is 20 - 100 nm.

[0013] Furthermore, the micron-sized zirconia has a particle size of 5 - 20 μm, the zirconia after treatment has a particle size of 20 - 50 nm, the alkali solution is at least one aqueous solution of sodium hydroxide or potassium hydroxide, and the alkali concentration is 0.5 - 2 wt%. The mass-to-volume ratio of the micron-sized zirconia to the alkali solution is 1 g : 5 - 10 mL. In the present invention, the alkali solution is used as the medium for ball milling, and the processes of ball milling and alkali etching are completed synchronously. The resulting nano-sized zirconia after treatment has significantly improved hydrophilicity and does not agglomerate, and the nanoparticles are evenly dispersed. The inventors also found that if the zirconia is first ball milled to the same particle size and then alkali etching treatment is carried out, the effect is not good. In addition, the inventors' research found that the initial particle size of the zirconia particles has a significant impact on the modification effect. If the original particle size is too large, it is difficult for the alkali solution to fully etch its surface; if the particle size is too small, it is easy to form agglomerates or be over-crushed during ball milling, which is not conducive to the formation of modified particles with a uniform structure and good dispersibility. Therefore, controlling the initial particle size between 5 - 20 μm is the key to obtaining excellent performance.

[0014] Furthermore, and / or the support layer is selected from polyphenylene sulfide or fiber cloth; the thickness is 200 - 500 μm, and the mesh count is 40 - 100 meshes; the thickness of the casting solution layer is 200 - 300 μm.

[0015] Furthermore, the film-forming polymer is selected from at least one of polysulfone, polyethersulfone, polyphenylsulfone, polyketone, polyimide, polyetherimide, polyphenylene copolymer, and polyetheretherketone; the mass ratio of the modified zirconia particles to the film-forming polymer is 70:30 to 90:10, preferably 80:20 to 85:15; the organic solvent is selected from at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-diethylacetamide, and dimethyl sulfoxide; the amount of the organic solvent is such that the solid content of the casting solution is 30 - 50%.

[0016] Furthermore, there is also a complexing agent in the alkali solution, and the complexing agent is selected from one or more of disodium ethylenediaminetetraacetate (EDTA-Na2), sodium citrate, or sodium oxalate, and the molar ratio of the complexing agent to zirconia is 1 - 3:1. The complexing agent combines with the etched Zr 4+ to form a soluble complex, which can enhance the dissolution effect of zirconium ions, reduce the ion concentration around the reaction site, and improve the etching efficiency and modification uniformity.

[0017] The rotor, grinding chamber and ceramic balls of the ball milling equipment are all made of zirconia. The ball milling conditions are that the ball-to-material ratio is (5-15):1, the ball milling speed is 400-700 rpm, and the ball milling time is 30-60 min.

[0018] Furthermore, the casting solution further includes a membrane pore size regulator, which is selected from at least one of polyvinylpyrrolidone (PVP), polyvinyl alcohol, polyacrylic acid and its related esters. The dosage of the membrane pore size regulator is 1-2 wt% of the mass of the film-forming polymer.

[0019] Furthermore, non-solvent induced phase inversion is completed by immersing the support layer coated with the casting solution in water.

[0020] The present invention conducts structural regulation on micron-sized zirconia particles through the combined 'ball milling - alkali etching' synchronous process. Under controlled conditions, the combination of ball milling treatment and alkali etching treatment can effectively improve the dispersion degree and reaction opportunity of zirconia powder, thereby significantly improving the efficiency of the etching process. In a preferred technical solution of the present invention, a complexing agent is introduced to enhance the dissolution effect of zirconium ions, which can further improve the reaction efficiency and optimize the surface roughness and hydrophilicity of the particles. This method significantly improves the surface activity and hydrophilic properties of zirconia particles, provides a reliable guarantee for their uniform distribution and interfacial bonding in the composite separator, and thus helps to improve the ionic conductivity and stability of the separator.

[0021] The present invention also provides a preparation method of an alkaline electrolyzed water hydrogen production separator modified based on zirconia, comprising the following steps:

[0022] (S1) Dispersing micron-sized zirconia powder in an alkaline solution, performing ball milling treatment, and then washing and drying to obtain modified zirconia particles with a particle size of 20-100 nm;

[0023] (S2) Dispersing the film-forming polymer and the modified zirconia particles in an organic solvent and mixing evenly to obtain a casting solution;

[0024] (S3) Uniformly coating the casting solution on the surface of the support layer and performing non-solvent induced phase inversion in water to obtain a structurally stable modified alkaline electrolyzed water hydrogen production separator.

[0025] Further, in step (S1), the micron-sized zirconia has a particle size of 5-20 μm, the processed zirconia has a particle size of 20-50 nm, the alkaline solution is at least one aqueous solution of sodium hydroxide or potassium hydroxide, the concentration of the alkali in the alkaline solution is 0.5-2 wt%, preferably 1-1.5 wt%; the mass-volume ratio of the micron-sized zirconia to the alkaline solution is 1 g: 5-10 mL; the ball milling process has a ball-to-material ratio of 5-15:1, a ball milling speed of 400-700 rpm, and a ball milling time of 30-60 min; the rotor, the grinding chamber, and the ceramic balls are all made of zirconia. The material of the ball milling and the material to be ball milled are the same material to avoid introducing other impurities.

[0026] Further, in step (S1), a complexing agent is added to the alkaline solution. The complexing agent combines with the zirconium ions generated by etching to form a soluble complex, so as to enhance the dissolution effect of zirconium ions, reduce the ion concentration around the reaction site, and improve the efficiency of the etching reaction. The complexing agent is selected from one or more of sodium ethylenediaminetetraacetate (EDTA-Na2), sodium citrate, or sodium oxalate, and the molar ratio to zirconia is (1-3):1.

[0027] Further, in step (S2), the film-forming polymer is selected from at least one of polysulfone, polyethersulfone, polyphenylsulfone, polyketone, polyimide, polyetherimide, polyphenylene copolymer, and polyetheretherketone; the mass ratio of the modified zirconia particles to the film-forming polymer is 70:30-90:10; the organic solvent is selected from at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-diethylacetamide, and dimethyl sulfoxide; the amount of the organic solvent is such that the solid content of the casting solution is 30-50%.

[0028] Further, in step (S2), a membrane pore size regulator is added to the casting solution. The membrane pore size regulator and other components are dispersed in the solvent together to form a casting solution; the membrane pore size regulator is selected from at least one of polyvinylpyrrolidone (PVP), polyvinyl alcohol, polyacrylic acid and its esters, the molecular weight of the membrane pore size regulator is 20000-40000, and the amount of the membrane pore size regulator is 1-2 wt% of the mass of the film-forming polymer.

[0029] According to another aspect of the present invention, there is provided an application of the above-mentioned alkaline electrolyzed water hydrogen production membrane modified with zirconia in an alkaline electrolyzed water hydrogen production system, used as an ion exchange membrane to achieve efficient conduction of hydroxide ions, while effectively blocking the cross-permeation of anode and cathode gases, and ensuring the safety and efficiency of system operation.

[0030] In the alkaline electrolyzed water hydrogen production membrane modified with zirconia provided by the present invention, the modified zirconia particles are micron-sized zirconia particles, which are ball-milled together with the alkali solution, and simultaneously ground and alkali-etched, significantly improving the specific surface area and surface hydrophilicity of the particles, improving the dispersion state of the particles in the polymer matrix, enhancing the interfacial bonding force with the membrane material, and effectively constructing a continuous hydrophilic conduction channel. During the etching process, by precisely controlling the reaction temperature, concentration and time, and a complexing agent can be introduced to accelerate the dissolution of zirconium ions, greatly improving the etching efficiency and avoiding particle agglomeration and over-corrosion phenomena. The prepared membrane exhibits excellent ion conduction performance, gas barrier ability and long-term use stability in an alkaline electrolyzed water environment, providing a new technical path and theoretical support for the large-scale application of high-performance membranes. Description of the Drawings

[0031] Figure 1 SEM image of the modified zirconia particles prepared in Preparation Example 1;

[0032] Figure 2 Contact angle comparison diagram of the modified zirconia particles and unmodified particles prepared in Example 1;

[0033] Figure 3 FTIR spectra of the modified zirconia particles prepared in Example 1 with different ball-milling times;

[0034] Figure 4 Surface SEM image of the modified alkaline electrolyzed water hydrogen production membrane prepared in Example 1;

[0035] Figure 5 Cross-section SEM image of the modified alkaline electrolyzed water hydrogen production membrane prepared in Example 1. Detailed Description of the Invention

[0036] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments.

[0037] In the following examples, the experimental methods are all conventional methods unless otherwise specified; the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0038] The rotor, grinding chamber and ceramic balls of the ball-milling equipment are all made of zirconia.

[0039] Preparation Example 1: Preparation of Modified Zirconia Particles and Modified Membrane

[0040] (S1) Disperse 10 g of zirconia particles (particle size 10 μm) in 50 mL of an aqueous NaOH solution with a concentration of 1 wt%, add it to a ball-milling equipment, with a ball-to-material ratio of 10:1, a ball-milling speed of 500 rpm, ball-mill for 45 min, wash and dry, and the particle size of the obtained modified zirconia is about 30 nm;

[0041] Figure 1 It is a scanning electron microscope image of modified zirconia particles. After etching treatment, the zirconia particles are evenly dispersed and there is no obvious agglomeration phenomenon.

[0042] Figure 2 It is a test diagram of the contact angle of modified zirconia particles with water to evaluate their hydrophilic properties. It can be seen that compared with the unetched zirconia particles, the water contact angle of the etched zirconia modified nanoparticles is significantly reduced, proving that the alkali etching treatment method proposed in the present invention can effectively improve the hydrophilicity of the particles.

[0043] Figure 3 It is the FTIR diagram of modified zirconia obtained by ball milling for different times. It can be seen that the appearance of the -OH characteristic peak at around 3400 cm - -1 and the morphological change of the Zr-O characteristic peak at 615 cm - -1 indicate that ball milling and alkali etching have completed the modification of the particle surface.

[0044] (S2) Mix the modified zirconia particles, polysulfone (PSU, molecular weight 80000), and polyvinylpyrrolidone (PVP, molecular weight 40000) in a mass ratio of 85:15:0.2, use N-methylpyrrolidone (NMP) as the solvent to prepare a casting solution with a solid content of 40%, use a polyphenylene sulfide (PPS, mesh size 40 mesh) grid with a thickness of 250 μm as the support, set the doctor blade height to 300 μm (the thickness of the casting solution layer after scraping is 300 μm), use a film scraping machine to evenly scrape the casting solution on the base film at a speed of 20 mm / s, and then immerse it in deionized water for phase conversion to obtain a base film for alkaline electrolytic water hydrogen production diaphragm.

[0045] Figure 4 It is the surface SEM image of the prepared modified alkaline electrolytic water hydrogen production diaphragm. Figure 5 It is the cross-sectional SEM image of the modified alkaline electrolytic water hydrogen production diaphragm prepared in Example 1. It can be seen that the particles are evenly dispersed in the base film, no obvious particle agglomeration phenomenon is observed, the membrane structure is dense and uniform, and there are no obvious defects, indicating that the etched particles have good interfacial bonding with the base film material and excellent film-forming performance.

[0046] (S3) Cut the diaphragm into appropriate sizes, install it in the electrolytic cell, and measure the area resistance in a 30 wt% KOH solution at 80 °C. The area resistance is 0.17 Ω·cm 2 (NaOH solution concentration 1 wt%, ball milling time 45 min, micron-sized zirconia particle size 10 μm). Immerse the diaphragm prepared in Example 1 in a 30 wt% KOH solution. After 1000 h of continuous immersion, the area resistance of the diaphragm becomes 0.19 Ω·cm 2, it basically did not decrease, proving the alkali resistance of the modified separator prepared in Example 1.

[0047] In step S1, the ball milling time, alkali concentration, and particle size of micron-sized zirconia were changed respectively, and the surface resistance of the finally obtained separator was tested. The results are shown in Table 1 (different ball milling times), Table 2 (different alkali concentrations), and Table 3 (different particle sizes of micron-sized zirconia) below.

[0048] Table 1 Area resistance of separators prepared by ball milling treatment with different ball milling times

[0049] Ball milling time (min) <![CDATA[Sheet Resistance (Ω·cm 2 )]]> 20 0.23 30 0.19 45 0.17 60 0.20 90 0.25

[0050] Table 2 Area resistance of separators prepared by ball milling treatment with different alkali concentrations

[0051] Alkali concentration (wt%) <![CDATA[Sheet resistance (Ω·cm 2 )]]> 0.5 0.26 1.0 0.18 1.5 0.19 2.0 0.22 3.0 0.18

[0052] Table 3 Area resistance of separators prepared by ball milling treatment with different particle sizes of micron-sized zirconia

[0053] Micron-sized zirconia particle size (μm) <![CDATA[Sheet Resistance (Ω·cm 2 )]]> 3 0.27 5 0.20 10 0.18 20 0.22 30 0.33

[0054] Example 2

[0055] Other conditions are the same as those in Example 1. The difference is that in step S2, the mass ratio of modified zirconia particles to polysulfone is 75:25. The area resistance of the finally obtained electrolytic water hydrogen production separator under the condition of 30% KOH solution is 0.26 Ω·cm 2 .

[0056] Example 3

[0057] Other conditions are the same as those in Example 1. The difference is that step S1 is changed to: 10 g of zirconia particles (particle size 10 μm) are dispersed in 50 mL of an aqueous NaOH solution with a concentration of 1 wt%, and disodium ethylenediaminetetraacetate with a molar amount of zirconia is added to obtain a mixed solution. The mixed solution is added to a ball milling device with a ball-to-material ratio of 10:1, a ball milling speed of 500 rpm, and ball milling for 45 min. After washing and drying, the particle size of the obtained modified zirconia is about 30 nm. Steps S2 and S3 are the same as those in Example 1. The area resistance of the finally obtained electrolytic water hydrogen production separator under the condition of 30% KOH solution is 0.15 Ω·cm 2 . After the separator prepared in Example 3 was immersed in 30 wt% KOH solution for 1000 h, the area resistance of the separator was 0.16 Ω·cm 2 . It shows that adding a complexing agent to the alkali solution can improve the conductivity and alkali resistance of the separator to a certain extent.

[0058] Example 4

[0059] Other conditions are the same as in Example 1, except that step S1 is modified as follows: 10 g of zirconia particles (particle size 10 μm) are dispersed in 50 mL of a NaOH solution with a concentration of 1 wt%, and sodium citrate with a molar amount of zirconia 1 time is added to obtain a mixed solution. The mixed solution is added to a ball milling equipment with a ball-to-material ratio of 10:1, a ball milling speed of 500 rpm, and ball milled for 45 min, followed by washing and drying. The particle size of the obtained modified zirconia is about 30 nm. Steps S2, S3 are the same as in Example 1. The area resistance of the finally obtained electrolytic water hydrogen production membrane under the condition of 30% KOH solution is 0.16 Ω·cm 2 . After the membrane prepared in Example 4 was immersed in 30 wt% KOH solution for 1000 h, the area resistance of the membrane was 0.17 Ω·cm 2 .

[0060] Comparative Example 1

[0061] Other conditions are the same as in Example 1, except that step S1 is modified as follows: 10 g of zirconia particles (particle size 10 μm) are ball milled under the conditions of a ball-to-material ratio of 10:1, a ball milling speed of 500 rpm, and ball milled for 45 min. The particle size of the zirconia after ball milling is about 30 nm. The nano-sized zirconia after ball milling is impregnated in 1 wt% NaOH solution at 50 °C for different times, and then washed and dried to obtain modified zirconia. Steps S2, S3 are the same as in Example 1. The performance of the obtained membrane was tested, and the results are shown in Table 4 below.

[0062] Table 4 Membrane Performance Test

[0063]

[0064]

Claims

1. An alkaline electrolyzed water hydrogen production diaphragm modified by zirconia, characterized in that, It includes a support layer and a hydrophilic modified coating on the support layer. The hydrophilic modified coating is obtained by non-solvent induced phase inversion after a casting solution prepared from modified zirconia particles, a film-forming polymer, and an organic solvent is coated on the support layer. The modified zirconia particles are obtained by ball milling micron-sized zirconia and an alkali solution in a ball mill, and the particle size of the zirconia after ball milling is 20 - 100 nm.

2. The alkaline electrolyzed water hydrogen production diaphragm according to claim 1, wherein, The micron-sized zirconia has a particle size of 5 - 20 μm, and the particle size of the zirconia after treatment is 20 - 50 nm; the alkali solution is an aqueous solution of at least one of sodium hydroxide and potassium hydroxide, and the alkali concentration is 0.5 - 2 wt%; the mass-to-volume ratio of the micron-sized zirconia to the alkali solution is 1 g: 5 - 10 mL.

3. The alkaline electrolyzed water hydrogen production diaphragm according to claim 1, characterized in that, And / or the support layer is selected from polyphenylene sulfide or fibrous cloth; the thickness is 200 - 500 μm, and the mesh count is 40 - 100 meshes; the thickness of the casting solution layer is 200 - 300 μm.

4. The alkaline electrolyzed water hydrogen production diaphragm according to claim 1, wherein The film-forming polymer is selected from at least one of polysulfone, polyethersulfone, polyphenylsulfone, polyketone, polyimide, polyetherimide, polyphenylene copolymer, and polyetheretherketone; the mass ratio of the modified zirconia particles to the film-forming polymer is 70:30 to 90:10, preferably 80:20 to 85:15; the organic solvent is selected from at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-diethylacetamide, and dimethyl sulfoxide; the amount of the organic solvent is such that the solid content of the casting solution is 30 - 50%.

5. The alkaline electrolyzed water hydrogen production diaphragm according to claim 1, wherein, The alkali solution also contains a complexing agent, and the complexing agent is selected from one or more of sodium ethylenediaminetetraacetate (EDTA-Na2), sodium citrate, or sodium oxalate, and the molar ratio of the complexing agent to zirconia is 1 - 3:

1.

6. The alkaline electrolyzed water hydrogen production diaphragm according to claim 1, wherein The rotor, grinding chamber, and ceramic balls of the ball milling equipment are all made of zirconia. The ball milling conditions are that the ball-to-material ratio is (5 - 15):1, the ball milling speed is 400 - 700 rpm, and the ball milling time is 30 - 60 min; Furthermore, the casting solution also includes a membrane pore size regulator, and the membrane pore size regulator is selected from at least one of polyvinylpyrrolidone (PVP), polyvinyl alcohol, polyacrylic acid, and its related esters. The amount of the membrane pore size regulator is 1 - 2 wt% of the mass of the film-forming polymer.

7. The preparation method of the zirconia-modified alkaline electrolyzed water hydrogen production diaphragm according to any one of claims 1-6, characterized in that, It includes the following steps: (S1) Disperse the micron-sized zirconia powder in the alkali solution, conduct ball milling treatment, then wash and dry to obtain modified zirconia particles with a particle size of 20 - 100 nm; (S2) Disperse the film-forming polymer and the modified zirconia particles in the organic solvent and mix evenly to obtain a casting solution; (S3) Uniformly coat the casting solution on the surface of the support layer and place it in water for non-solvent induced phase inversion to obtain a structurally stable modified alkaline electrolytic water hydrogen production diaphragm.

8. The preparation method according to claim 7, characterized in that, In step (S1), the particle size of micron-sized zirconia is 5-20 μm, the particle size of the treated zirconia is 20-50 nm, the alkaline solution is an aqueous solution of at least one of sodium hydroxide and potassium hydroxide, the concentration of the alkali in the alkaline solution is 0.5-2 wt%, preferably 1-1.5 wt%; the mass-volume ratio of micron-sized zirconia to the alkaline solution is 1 g: 5-10 mL; the ball milling process has a ball-to-material ratio of 5-15:1, a ball milling speed of 400-700 rpm, and a ball milling time of 30-60 min; the rotor, the grinding chamber, and the ceramic balls are all made of zirconia. The material for ball milling and the material to be ball milled are the same material to avoid introducing other impurities.

9. The preparation method according to claim 7, characterized in that, In step (S1), a complexing agent is further added to the alkaline solution. The complexing agent is selected from one or more of disodium ethylenediaminetetraacetate (EDTA-Na2), sodium citrate, or sodium oxalate, and the molar ratio to zirconia is (1-3):

1.

10. The preparation method according to claim 7, wherein, In step (S2), a membrane pore size regulator is added to the casting solution. The membrane pore size regulator and other components are dispersed in a solvent together to form the casting solution; the membrane pore size regulator is selected from at least one of polyvinylpyrrolidone (PVP), polyvinyl alcohol, polyacrylic acid and its esters, the molecular weight of the membrane pore size regulator is 20,000-40,000, and the dosage of the membrane pore size regulator is 1-2 wt% of the mass of the film-forming polymer.

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