A doped nickel oxide modified polysulfone composite separator material and a preparation method thereof

Abstract

The application belongs to the technical field of hydrogen energy conversion by electrolysis of water, and particularly relates to a doped nickel oxide modified polysulfone composite diaphragm material and a preparation method thereof, which comprises uniformly dispersing polysulfone in N-methyl pyrrolidone to obtain a polysulfone solution, adding PVP or PEG to the polysulfone solution, stirring until complete dissolution to obtain a mixed solution, adding a doped nickel oxide material to the mixed solution, stirring until complete uniform dispersion to obtain a casting solution, degassing the casting solution by stirring, laying the casting solution on the front end of a doctor blade, sliding the doctor blade at a uniform speed to uniformly spread the casting solution on the surface of a glass film to obtain a liquid membrane, pre-evaporating the liquid membrane in air, immersing the pre-evaporated liquid membrane in deionized water to solidify into a film, peeling off the film and cleaning to obtain the doped nickel oxide modified polysulfone composite diaphragm material. By introducing the doped nickel oxide as a functional modification material, the hydrophilicity and conductivity of the diaphragm are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of water electrolysis for hydrogen production and energy conversion technology, specifically relating to a nickel oxide-modified polysulfone composite membrane material and its preparation method. Background Technology

[0002] Hydrogen production through water electrolysis converts electrical energy into hydrogen energy and is a potential technology to facilitate the large-scale consumption of renewable energy in the future. Currently, water electrolysis hydrogen production technology has been gradually commercialized and is being applied on a large scale.

[0003] In water electrolysis hydrogen production equipment, hydrogen is produced at the cathode and oxygen at the anode. The hydrogen and oxygen produced are separated by a membrane. The quality of the membrane directly affects the overall gas purity and power consumption of the equipment. Early membrane materials were generally asbestos, but its problems such as swelling in alkaline electrolytes, high-temperature instability, high internal resistance, and high carcinogenicity have led to its gradual obsolescence. Currently, the industry widely uses new composite membranes based on polyphenylene sulfide (PPS) fabric. However, the weak hydrophilicity of PPS fabric can cause excessive internal resistance in the electrolyzer. Functional coatings are often used to improve its hydrophilicity; commonly used functional coatings include zirconium oxide, titanium oxide, and cerium oxide. However, these functional coatings have stability issues. The interaction between the functional coating and the PPS fabric is weak, and long-term use can lead to coating peeling. Furthermore, if too much modified material is added to the functional coating, it can cause local particle aggregation, leading to a decrease in the porosity of the membrane material and hindering the transport of hydroxide ions in the electrolyte. Summary of the Invention

[0004] The purpose of this invention is to provide a nickel oxide-modified polysulfone composite membrane material and its preparation method, so as to solve the technical problem that the low porosity of the membrane material in the prior art hinders the transport of hydroxide ions in the electrolyte.

[0005] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, this application discloses a nickel oxide-modified polysulfone composite membrane material, comprising nickel oxide, polysulfone, polyvinylpyrrolidone, and polyethylene glycol.

[0006] Secondly, this application discloses a method for preparing a nickel oxide-modified polysulfone composite membrane material, comprising: Polysulfone is uniformly dispersed in N-methylpyrrolidone to obtain a polysulfone solution. PVP or PEG is added to the polysulfone solution and stirred until completely dissolved to obtain a mixed solution. Add the doped nickel oxide material to the mixed solution and stir until it is completely and uniformly dispersed to obtain the casting solution; then stir the casting solution for degassing. The casting solution is laid on the front end of the doctor blade, and the doctor blade is slid at a uniform speed to spread the casting solution evenly on the surface of the glass film to form a liquid film. The liquid membrane was pre-evaporated by being left to stand in the air. The pre-evaporated liquid membrane was then immersed in deionized water to solidify into a film. After the film was removed and cleaned, a nickel oxide-modified polysulfone composite membrane material was obtained.

[0007] Preferably, the polysulfone content in the polysulfone solution is 10-40 wt%.

[0008] Preferably, the content of PVP or PEG in the mixed solution is 0.5-30 wt%.

[0009] Preferably, the content of the doped nickel oxide material in the casting solution is 35-70 wt%.

[0010] Preferably, the casting solution is stirred at 40-70 r / min for 2-2.5 h to degas it.

[0011] Preferably, when preparing the liquid membrane, the distance between the doctor blade and the glass membrane is 200-500 μm; the liquid membrane is pre-evaporated by standing in the air for 10-40 seconds.

[0012] Preferably, the liquid membrane is rapidly immersed in deionized water at 15-60℃ and solidified into a film after 5-30 seconds. After being removed from the glass membrane surface, it is immersed in deionized water at room temperature for 3-10 minutes. This process is repeated 3 times to obtain a nickel oxide-modified polysulfone composite membrane material.

[0013] Preferably, the doped nickel oxide is prepared by the following steps: Add one of the following aqueous solutions to an aqueous nickel nitrate solution: copper nitrate, zinc nitrate, cesium nitrate, urea, or thiourea, and mix thoroughly to obtain mixed solution A. After adding polyethylene glycol to mixed solution A and stirring, sodium hydroxide solution is slowly added dropwise to adjust the pH value to 12, and then stirred evenly to obtain mixed solution B. Mixed solution B undergoes a hydrothermal reaction to obtain a reaction solution. After the reaction solution is cooled to room temperature, it is washed and the precipitate is removed. After drying the precipitate to constant weight, it was subjected to constant temperature heat treatment and then naturally cooled to obtain doped nickel oxide.

[0014] Preferably, the concentration of the nickel nitrate aqueous solution is 1.5-1.8 mol / L; 3-10% of 1 mol / L copper nitrate, zinc nitrate, cesium nitrate, urea or thiourea is added to obtain mixed solution A; Add 1-3% polyethylene glycol to mixed solution A, stir for 20-40 min, then slowly add sodium hydroxide solution dropwise to adjust the pH to 12, and continue stirring for 20-40 min to obtain mixed solution B; Mixed solution B was subjected to hydrothermal reaction at 140-200℃ for 12-24 hours to obtain a reaction solution. After the reaction solution was cooled to room temperature, it was washed with deionized water and centrifuged to obtain the precipitate. After drying the precipitate to constant weight at 60-80℃, it is subjected to constant temperature heat treatment for 1-3 hours at a constant temperature of 200-400℃, and then naturally cooled to obtain doped nickel oxide.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a nickel oxide-modified polysulfone composite membrane material. By introducing nickel oxide as a functional modifier, the hydrophilicity and conductivity of the membrane are effectively improved. This nickel oxide material is doped with copper, cesium, zinc, and other cations via a hydrothermal method, which can form surface defects and oxygen vacancies at nickel sites, enhancing the adsorption capacity for hydroxide ions. Simultaneously, the doping with nitrogen and sulfur elements can form Ni-N or Ni-S bonds with nickel, increasing the surface energy of the material and improving particle wettability. Combined with polysulfone as the matrix material and polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) as pore size control agents, the resulting composite membrane not only possesses excellent hydrophilicity and ion conductivity but also maintains good thermal stability and alkali resistance, making it suitable for efficient and long-life water electrolysis hydrogen production processes.

[0016] This invention proposes a method for preparing nickel-doped polysulfone composite membrane materials. Through a phase inversion process, functionalized doped nickel oxide is uniformly introduced into the polysulfone matrix, achieving material structure consistency and stable anchoring of functional components. The method first uniformly dissolves polysulfone in N-methylpyrrolidone, then adds PVP or PEG to regulate the membrane pore structure. Finally, the doped nickel oxide material is introduced, and prolonged stirring and degassing ensure its uniform dispersion in the casting solution. After coating, pre-evaporation and immersion precipitation phase inversion result in a membrane with high porosity, good mechanical strength, and hydrophilic stability. This method is simple to operate, operates under mild conditions, requires a small amount of doped material, and is not prone to agglomeration, making it suitable for industrial production. It significantly improves the performance and lifespan of the membrane in alkaline water electrolysis hydrogen production environments. (1) The doped nickel oxide material can replace nickel ions with cations such as copper ions, cesium ions, and zinc ions by hydrothermal method to increase surface defects and oxygen vacancies, and promote the adsorption of hydroxide ions; the doped nickel oxide material can form Ni-N bonds and Ni-S bonds with nickel ions by hydrothermal method to increase the surface energy of the material and improve the wettability of particles; in addition, the nickel oxide material is doped by hydrothermal synthesis method, and high temperature water vapor will form hydroxyl groups on its surface during the reaction process, which will improve the hydrophilicity of the material.

[0017] (2) When modifying the electrolytic hydrogen production membrane material with this type of nickel oxide doped material, the amount added is small. The modified polysulfone membrane material prepared by the phase inversion method has good stability, and the doped material is not easy to fall off due to chemical bonding. In the phase inversion preparation process, the amount of nickel oxide doped material added during the preparation of the casting solution is small, the nickel oxide doped material is not easy to agglomerate, the viscosity of the casting solution is moderate, and the porosity of the polysulfone membrane formed is high. Detailed Implementation

[0018] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0019] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0020] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0021] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0022] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0023] The present invention will now be described in further detail: This application discloses a nickel oxide-modified polysulfone composite membrane material, comprising nickel oxide, polysulfone, polyvinylpyrrolidone, and polyethylene glycol. This material exhibits excellent thermal stability, alkali resistance, hydrophilicity, and high porosity. Furthermore, the nickel oxide-modified material achieves good hydrophilicity even with low addition amounts, resulting in good stability and a long service life during membrane use.

[0024] This application also discloses a method for preparing a nickel oxide-modified polysulfone composite membrane material, including: Polysulfone is uniformly dispersed in N-methylpyrrolidone to obtain a polysulfone solution. PVP or PEG is added to the polysulfone solution and stirred until completely dissolved to obtain a mixed solution. Add the doped nickel oxide material to the mixed solution and stir until it is completely and uniformly dispersed to obtain the casting solution; then stir the casting solution for degassing. The casting solution is laid on the front end of the doctor blade, and the doctor blade is slid at a uniform speed to spread the casting solution evenly on the surface of the glass film to form a liquid film. The liquid membrane was pre-evaporated by being left to stand in the air. The pre-evaporated liquid membrane was then immersed in deionized water to solidify into a film. After the film was removed and cleaned, a nickel oxide-modified polysulfone composite membrane material was obtained.

[0025] The electrolytic hydrogen production membrane with a functional coating has several drawbacks. Firstly, the interaction between the functional coating and the polyphenylene sulfide (PPS) fabric is weak, leading to coating peeling over long-term use. Secondly, excessive addition of hydrophilic modifiers to the functional coating can cause localized particle aggregation, reducing the membrane material's porosity and hindering hydroxide ion transport in the electrolyte. This invention proposes a nickel-doped, nickel-modified polysulfone composite membrane material for electrolytic hydrogen production and its preparation method. The nickel-doped material is doped with copper, cesium, and zinc ions via a hydrothermal method. This substitution of nickel ions increases surface defects and oxygen vacancies, promoting hydroxide ion adsorption. Secondly, the nickel-doped material is doped with nitrogen and sulfur elements via a hydrothermal method, forming Ni-N and Ni-S bonds with nickel ions, increasing surface energy and improving particle wettability. Thirdly, the hydrothermal synthesis method for nickel doping allows high-temperature water vapor to form hydroxyl groups on the surface, enhancing the material's hydrophilicity. The electrolytic hydrogen production membrane material modified with this type of nickel oxide-doped material requires a small amount of additive. The modified polysulfone membrane material prepared by the phase inversion method has good stability, and the dopant material is not easily detached due to chemical bonding. In the phase inversion preparation process, the amount of nickel oxide-doped material added during the preparation of the casting solution is small, the nickel oxide-doped material is not easy to agglomerate, the viscosity of the casting solution is moderate, and the resulting polysulfone membrane has high porosity.

[0026] In some embodiments, a method for preparing a nickel oxide-doped modified polysulfone composite membrane material includes: Polysulfone was uniformly dispersed in N-methylpyrrolidone to obtain a polysulfone solution. PVP or PEG was added to the polysulfone solution and stirred until completely dissolved to obtain a mixed solution. The content of polysulfone in the polysulfone solution was 10-40 wt%. Add the doped nickel oxide material to the mixed solution and stir until it is completely and uniformly dispersed to obtain the casting solution; then stir the casting solution for degassing. The casting solution is laid on the front end of the doctor blade, and the doctor blade is slid at a uniform speed to spread the casting solution evenly on the surface of the glass film to form a liquid film. The liquid membrane was pre-evaporated by being left to stand in the air. The pre-evaporated liquid membrane was then immersed in deionized water to solidify into a film. After the film was removed and cleaned, a nickel oxide-modified polysulfone composite membrane material was obtained.

[0027] In some embodiments, a method for preparing a nickel oxide-doped modified polysulfone composite membrane material includes: Polysulfone was uniformly dispersed in N-methylpyrrolidone to obtain a polysulfone solution. PVP or PEG was added to the polysulfone solution and stirred until completely dissolved to obtain a mixed solution. The content of PVP or PEG in the mixed solution was 0.5-30 wt%. Add the doped nickel oxide material to the mixed solution and stir until it is completely and uniformly dispersed to obtain the casting solution; then stir the casting solution for degassing. The casting solution is laid on the front end of the doctor blade, and the doctor blade is slid at a uniform speed to spread the casting solution evenly on the surface of the glass film to form a liquid film. The liquid membrane was pre-evaporated by being left to stand in the air. The pre-evaporated liquid membrane was then immersed in deionized water to solidify into a film. After the film was removed and cleaned, a nickel oxide-modified polysulfone composite membrane material was obtained.

[0028] In some embodiments, a method for preparing a nickel oxide-doped modified polysulfone composite membrane material includes: Polysulfone is uniformly dispersed in N-methylpyrrolidone to obtain a polysulfone solution. PVP or PEG is added to the polysulfone solution and stirred until completely dissolved to obtain a mixed solution. Add the doped nickel oxide material to the mixed solution and stir until completely and uniformly dispersed to obtain a casting solution; then degas the casting solution; the content of the doped nickel oxide material in the casting solution is 35-70 wt%. The casting solution is laid on the front end of the doctor blade, and the doctor blade is slid at a uniform speed to spread the casting solution evenly on the surface of the glass film to form a liquid film. The liquid membrane was pre-evaporated by being left to stand in the air. The pre-evaporated liquid membrane was then immersed in deionized water to solidify into a film. After the film was removed and cleaned, a nickel oxide-modified polysulfone composite membrane material was obtained.

[0029] In some embodiments, a method for preparing a nickel oxide-doped modified polysulfone composite membrane material includes: Polysulfone is uniformly dispersed in N-methylpyrrolidone to obtain a polysulfone solution. PVP or PEG is added to the polysulfone solution and stirred until completely dissolved to obtain a mixed solution. Add the doped nickel oxide material to the mixed solution and stir until it is completely and uniformly dispersed to obtain the casting solution; then stir the casting solution for degassing. The casting solution is laid on the front end of the doctor blade, and the doctor blade is slid at a uniform speed to spread the casting solution evenly on the surface of the glass film to form a liquid film. The liquid membrane was pre-evaporated by being left to stand in air. The pre-evaporated liquid membrane was then immersed in deionized water to solidify into a film. After removal and cleaning, a nickel oxide-modified polysulfone composite membrane material was obtained. The casting solution was then degassed by stirring at 40-70 r / min for 2-2.5 h.

[0030] In some embodiments, a method for preparing a nickel oxide-doped modified polysulfone composite membrane material includes: Polysulfone is uniformly dispersed in N-methylpyrrolidone to obtain a polysulfone solution. PVP or PEG is added to the polysulfone solution and stirred until completely dissolved to obtain a mixed solution. Add the doped nickel oxide material to the mixed solution and stir until it is completely and uniformly dispersed to obtain the casting solution; then stir the casting solution for degassing. The casting solution is spread on the front end of the doctor blade, and the doctor blade is slid at a constant speed to spread the casting solution evenly on the surface of the glass membrane to form a liquid membrane; when preparing the liquid membrane, the distance between the doctor blade and the glass membrane is 200-500μm; the liquid membrane is left to stand in the air for 10-40s for pre-evaporation; The liquid membrane was pre-evaporated by being left to stand in the air. The pre-evaporated liquid membrane was then immersed in deionized water to solidify into a film. After the film was removed and cleaned, a nickel oxide-modified polysulfone composite membrane material was obtained.

[0031] In some embodiments, a method for preparing a nickel oxide-doped modified polysulfone composite membrane material includes: Polysulfone is uniformly dispersed in N-methylpyrrolidone to obtain a polysulfone solution. PVP or PEG is added to the polysulfone solution and stirred until completely dissolved to obtain a mixed solution. Add the doped nickel oxide material to the mixed solution and stir until it is completely and uniformly dispersed to obtain the casting solution; then stir the casting solution for degassing. The casting solution is laid on the front end of the doctor blade, and the doctor blade is slid at a uniform speed to spread the casting solution evenly on the surface of the glass film to form a liquid film. The liquid membrane is allowed to stand in the air for pre-evaporation. After pre-evaporation, the liquid membrane is quickly immersed in deionized water at 15-60℃ and solidified into a film after 5-30 seconds. After being removed from the glass membrane surface, it is immersed in deionized water at room temperature for 3-10 minutes. This process is repeated 3 times to obtain a nickel oxide-modified polysulfone composite membrane material.

[0032] In some embodiments, the doped nickel oxide is prepared by the following steps, including: Add one of the following aqueous solutions to an aqueous nickel nitrate solution: copper nitrate, zinc nitrate, cesium nitrate, urea, or thiourea, and mix thoroughly to obtain mixed solution A. After adding polyethylene glycol to mixed solution A and stirring, sodium hydroxide solution is slowly added dropwise to adjust the pH value to 12, and then stirred evenly to obtain mixed solution B. Mixed solution B undergoes a hydrothermal reaction to obtain a reaction solution. After the reaction solution is cooled to room temperature, it is washed and the precipitate is removed. After drying the precipitate to constant weight, it was subjected to constant temperature heat treatment and then naturally cooled to obtain doped nickel oxide.

[0033] In some embodiments, the concentration of the nickel nitrate aqueous solution is 1.5-1.8 mol / L; 3-10% of 1 mol / L copper nitrate, zinc nitrate, cesium nitrate, urea or thiourea is added to obtain mixed solution A; Add 1-3% polyethylene glycol to mixed solution A, stir for 20-40 min, then slowly add sodium hydroxide solution dropwise to adjust the pH to 12, and continue stirring for 20-40 min to obtain mixed solution B; Mixed solution B was subjected to hydrothermal reaction at 140-200℃ for 12-24 hours to obtain a reaction solution. After the reaction solution was cooled to room temperature, it was washed with deionized water and centrifuged to obtain the precipitate. After drying the precipitate to constant weight at 60-80℃, it is subjected to constant temperature heat treatment for 1-3 hours at a constant temperature of 200-400℃, and then naturally cooled to obtain doped nickel oxide.

[0034] A nickel-doped polysulfone composite membrane material for hydrogen production via water electrolysis, mainly comprising nickel-doped nickel, polysulfone, polyvinylpyrrolidone (PVP), and polyethylene glycol (PEG). The nickel-doped nickel is prepared by hydrothermal synthesis, and the doping ions and elements mainly include one or more of copper ions, cesium ions, zinc ions, nitrogen elements, and sulfur elements.

[0035] The preparation process of the nickel oxide-modified electrolytic water hydrogen production polysulfone composite membrane material includes the preparation of nickel oxide-modified material and phase transformation modification to prepare polysulfone membrane.

[0036] The steps for preparing doped nickel oxide materials are as follows: Step 1, Preparation of precursor solution. Pour 1.8 mol / L nickel nitrate aqueous solution into an Erlenmeyer flask, and under magnetic stirring, add 3-10% of 1 mol / L copper nitrate (or zinc nitrate, cesium nitrate, urea, thiourea) aqueous solution and mix thoroughly. Then, add 1-3% polyethylene glycol (PEG) to the mixed solution A, continue stirring for 20-40 min, and slowly add sodium hydroxide solution dropwise to adjust the pH to 12. Continue stirring for 20-40 min, and then transfer the solution to a hydrothermal reactor.

[0037] Step 2, hydrothermal reaction. React the reaction vessel at 140-200℃ for 12-24 hours. After cooling to room temperature, remove the reaction solution. Wash the reaction solution with deionized water and centrifuge to obtain the precipitate.

[0038] Step 3, Drying and heat treatment. The precipitate is dried at 60-80℃ to constant weight. The precipitate powder is then placed in a muffle furnace for heat treatment for 1-3 hours at a constant temperature of 200-400℃, and then naturally cooled to obtain the doped nickel oxide material.

[0039] The steps for preparing polysulfone membranes by phase inversion modification are as follows: Step 1: Prepare the casting solution. Add 10-40 wt% polysulfone to N-methylpyrrolidone (NMP) and mechanically stir to obtain a uniformly dispersed polysulfone solution. Then, add 0.5-30 wt% PVP or PEG to the polysulfone solution and stir at 200-400 r / min at room temperature until completely dissolved. Finally, add 35-70 wt% of doped nickel oxide to the solution and continue stirring for 24 hours until completely and uniformly dispersed.

[0040] Step 2, Degassing of the casting solution. The casting solution is stirred at 40-70 r / min for 2 hours to degas it.

[0041] Step 3, casting. Set the distance between the doctor blade and the glass membrane to 200-500 μm. Before casting, spread the casting solution on the front end of the doctor blade and slide the doctor blade at a uniform speed to spread the casting solution evenly on the surface of the glass membrane to form a liquid film.

[0042] Step 4, Pre-evaporation. The liquid film obtained by the scraper coating is left to stand in the air for 10-40 seconds for pre-evaporation.

[0043] Step 5: Immersion precipitate phase inversion membrane preparation. The liquid membrane is rapidly immersed in deionized water at 15-60℃ and solidified into a membrane after 5-30 seconds. The membrane is then removed from the glass membrane surface to obtain a nickel oxide-modified polysulfone composite membrane material.

[0044] Step 6, membrane cleaning. Immerse the nickel oxide-doped modified polysulfone composite membrane material in room temperature deionized water for 3-10 minutes, repeating 3 times.

[0045] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0046] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0047] Example 1 The steps for preparing doped nickel oxide materials are as follows: Step 1, Preparation of precursor solution. Pour 1.8 mol / L nickel nitrate aqueous solution into an Erlenmeyer flask, and add 5% 1 mol / L copper nitrate aqueous solution while magnetically stirring, mixing thoroughly. Then, add 1% polyethylene glycol (PEG) to the mixture, continue stirring for 20-40 min, and slowly add sodium hydroxide solution dropwise to adjust the pH to 12. Continue stirring for 20-40 min, and then transfer the solution to a hydrothermal reactor.

[0048] Step 2, hydrothermal reaction. The reaction vessel was heated at 160°C for 16 hours. After cooling to room temperature, the reaction solution was removed. The reaction solution was washed with deionized water and centrifuged to obtain the precipitate.

[0049] Step 3, drying and heat treatment. The precipitate was dried at 60°C to constant weight. The precipitate powder was then placed in a muffle furnace for heat treatment for 2 hours at a constant temperature of 300°C, and naturally cooled to obtain copper-doped nickel oxide material.

[0050] The steps for preparing polysulfone membranes by phase inversion modification are as follows: Step 1: Prepare the casting solution. Add 15 wt% polysulfone to N-methylpyrrolidone (NMP) and mechanically stir to obtain a uniformly dispersed polysulfone solution. Then, add 15 wt% PEG to the polysulfone solution and stir at 300 r / min at room temperature until completely dissolved. Finally, add 35 wt% copper-doped nickel oxide to the solution and continue stirring for 24 hours until completely and uniformly dispersed.

[0051] Step 2, Degassing treatment of the casting solution. The casting solution is stirred at 60 r / min for 2 hours to perform degassing treatment.

[0052] Step 3, casting. Set the distance between the doctor blade and the glass membrane to 300 μm. Before casting, spread the casting solution on the front end of the doctor blade and slide the doctor blade at a uniform speed to spread the casting solution evenly on the surface of the glass membrane to form a liquid film.

[0053] Step 4, Pre-evaporation. The liquid film obtained by the scraper coating is left to stand in the air for 15 seconds for pre-evaporation.

[0054] Step 5: Immersion precipitate phase inversion membrane preparation. The liquid membrane is rapidly immersed in deionized water at 15°C and solidified into a membrane after 15 seconds. The membrane is then removed from the glass membrane surface to obtain a copper-doped nickel oxide modified polysulfone composite membrane material.

[0055] Step 6, membrane cleaning. Immerse the copper-doped nickel oxide modified polysulfone composite membrane material in room temperature deionized water for 5 minutes, repeating 3 times.

[0056] Example 2 The steps for preparing doped nickel oxide materials are as follows: Step 1, Preparation of precursor solution. Pour 1.5 mol / L nickel nitrate aqueous solution into an Erlenmeyer flask, and add 3% 1 mol / L zinc nitrate aqueous solution while magnetically stirring, mixing thoroughly. Then, add 2% polyethylene glycol (PEG) to the mixture, continue stirring for 20-40 min, and slowly add sodium hydroxide solution dropwise to adjust the pH to 12. Continue stirring for 20-40 min, and then transfer the solution to a hydrothermal reactor.

[0057] Step 2, hydrothermal reaction. The reaction vessel was heated at 180°C for 16 hours. After cooling to room temperature, the reaction solution was removed. The reaction solution was washed with deionized water and centrifuged to obtain the precipitate.

[0058] Step 3, drying and heat treatment. The precipitate was dried at 80°C to constant weight, and the precipitate powder was placed in a muffle furnace for heat treatment for 3 hours at a constant temperature of 400°C. After natural cooling, zinc-doped nickel oxide material was obtained.

[0059] The steps for preparing polysulfone membranes by phase inversion modification are as follows: Step 1: Prepare the casting solution. Add 15 wt% polysulfone to N-methylpyrrolidone (NMP) and mechanically stir to obtain a uniformly dispersed polysulfone solution. Then, add 15 wt% PVP to the polysulfone solution and stir at 300 r / min at room temperature until completely dissolved. Finally, add 40 wt% zinc-doped nickel oxide to the solution and continue stirring for 24 hours until completely and uniformly dispersed.

[0060] Step 2, Degassing treatment of the casting solution. The casting solution is stirred at 60 r / min for 2 hours to perform degassing treatment.

[0061] Step 3, casting. Set the distance between the doctor blade and the glass membrane to 400 μm. Before casting, spread the casting solution on the front end of the doctor blade and slide the doctor blade at a uniform speed to spread the casting solution evenly on the surface of the glass membrane to form a liquid film.

[0062] Step 4, Pre-evaporation. The liquid film obtained by the scraper coating is left to stand in the air for 10 seconds for pre-evaporation.

[0063] Step 5: Immersion precipitate phase inversion membrane preparation. The liquid membrane is rapidly immersed in deionized water at 15°C and solidified into a membrane after 5 seconds. The membrane is then removed from the glass membrane surface to obtain a zinc-doped nickel oxide modified polysulfone composite membrane material.

[0064] Step 6, membrane cleaning. Immerse the zinc-doped nickel oxide modified polysulfone composite membrane material in room temperature deionized water for 3 minutes, repeat 3 times.

[0065] Example 3 The steps for preparing doped nickel oxide materials are as follows: Step 1, Preparation of precursor solution. Pour 1.6 mol / L nickel nitrate aqueous solution into an Erlenmeyer flask, and add 8% 1 mol / L thiourea aqueous solution while magnetically stirring, mixing thoroughly. Then, add 1% polyethylene glycol (PEG) to the mixture, continue stirring for 20 min, and slowly add sodium hydroxide solution dropwise to adjust the pH to 12. Continue stirring for 30 min, and then transfer the solution to a hydrothermal reactor.

[0066] Step 2, hydrothermal reaction. The reaction vessel was heated at 160℃ for 18 hours. After cooling to room temperature, the reaction solution was removed. The reaction solution was washed with deionized water and centrifuged to obtain the precipitate.

[0067] Step 3, drying and heat treatment. The precipitate was dried at 60°C to constant weight, and the precipitate powder was placed in a muffle furnace for heat treatment for 1 hour at a constant temperature of 200°C, and then naturally cooled to obtain doped nickel oxide powder.

[0068] The steps for preparing polysulfone membranes by phase inversion modification are as follows: Step 1: Prepare the casting solution. Add 15 wt% polysulfone to N-methylpyrrolidone (NMP) and mechanically stir to obtain a uniformly dispersed polysulfone solution. Then, add 7 wt% PEG to the polysulfone solution and stir at 300 r / min at room temperature until completely dissolved. Finally, add 50 wt% sulfur-doped nickel oxide to the solution and continue stirring for 24 hours until completely and uniformly dispersed.

[0069] Step 2, Degassing treatment of the casting solution. The casting solution is stirred at 60 r / min for 2 hours to perform degassing treatment.

[0070] Step 3, casting. Set the distance between the doctor blade and the glass membrane to 500 μm. Before casting, spread the casting solution on the front end of the doctor blade and slide the doctor blade at a uniform speed to spread the casting solution evenly on the surface of the glass membrane to form a liquid film.

[0071] Step 4, Pre-evaporation. The liquid film obtained by the scraper coating is left to stand in the air for 15 seconds for pre-evaporation.

[0072] Step 5: Immersion precipitate phase inversion membrane preparation. The liquid membrane is rapidly immersed in deionized water at 15°C and solidified into a membrane after 15 seconds. The membrane is then removed from the glass membrane surface to obtain a sulfur-doped nickel oxide modified polysulfone composite membrane material.

[0073] Step 6, membrane cleaning. Immerse the sulfur-doped nickel oxide-modified polysulfone composite membrane material in room temperature deionized water for 5 minutes, repeating 3 times.

[0074] Example 4 The steps for preparing doped nickel oxide materials are as follows: Step 1, Preparation of precursor solution. Pour 1.7 mol / L nickel nitrate aqueous solution into an Erlenmeyer flask, and add 9% 1 mol / L thiourea aqueous solution while magnetically stirring, mixing thoroughly. Then, add 3% polyethylene glycol (PEG) to the mixture, continue stirring for 20 min, and slowly add sodium hydroxide solution dropwise to adjust the pH to 12. Continue stirring for 30 min, and then transfer the solution to a hydrothermal reactor.

[0075] Step 2, hydrothermal reaction. The reaction vessel was heated at 190℃ for 13 hours. After cooling to room temperature, the reaction solution was removed. The reaction solution was washed with deionized water and centrifuged to obtain the precipitate.

[0076] Step 3, drying and heat treatment. The precipitate was dried at 70°C to constant weight. The precipitate powder was then placed in a muffle furnace for heat treatment for 1 hour at a constant temperature of 200°C and allowed to cool naturally to obtain sulfur-doped nickel oxide powder.

[0077] The steps for preparing polysulfone membranes by phase inversion modification are as follows: Step 1: Prepare the casting solution. Add 10 wt% polysulfone to N-methylpyrrolidone (NMP) and mechanically stir to obtain a uniformly dispersed polysulfone solution. Then, add 30 wt% PEG to the polysulfone solution and stir at 300 r / min at room temperature until completely dissolved. Finally, add 65 wt% sulfur-doped nickel oxide to the solution and continue stirring for 24 hours until completely and uniformly dispersed.

[0078] Step 2, Degassing treatment of the casting solution. The casting solution is stirred at 70 r / min for 2 hours to perform degassing treatment.

[0079] Step 3, casting. Set the distance between the doctor blade and the glass membrane to 200 μm. Before casting, spread the casting solution on the front end of the doctor blade and slide the doctor blade at a uniform speed to spread the casting solution evenly on the surface of the glass membrane to form a liquid film.

[0080] Step 4, Pre-evaporation. The liquid film obtained by the scraper coating is left to stand in the air for 30 seconds for pre-evaporation.

[0081] Step 5: Immersion precipitate phase inversion membrane preparation. The liquid membrane is rapidly immersed in deionized water at 30°C and solidified into a membrane after 20 seconds. The membrane is then removed from the glass membrane surface to obtain a sulfur-doped nickel oxide modified polysulfone composite membrane material.

[0082] Step 6, membrane cleaning. Immerse the sulfur-doped nickel oxide-modified polysulfone composite membrane material in room temperature deionized water for 10 min, repeat 3 times.

[0083] Example 5 The steps for preparing doped nickel oxide materials are as follows: Step 1, Preparation of precursor solution. Pour 1.8 mol / L nickel nitrate aqueous solution into an Erlenmeyer flask, and add 10% 1 mol / L thiourea aqueous solution while magnetically stirring, mixing thoroughly. Then, add 1.5% polyethylene glycol (PEG) to the mixture, continue stirring for 20 min, and slowly add sodium hydroxide solution dropwise to adjust the pH to 12. Continue stirring for 30 min, and then transfer the solution to a hydrothermal reactor.

[0084] Step 2, hydrothermal reaction. The reaction vessel is heated to 200℃ for 24 hours. After cooling to room temperature, the reaction solution is removed. The reaction solution is washed with deionized water and centrifuged to obtain the precipitate.

[0085] Step 3, drying and heat treatment. The precipitate was dried at 65°C to constant weight, and the precipitate powder was placed in a muffle furnace for heat treatment for 1 h at a constant temperature of 350°C. After natural cooling, sulfur-doped nickel oxide powder was obtained.

[0086] The steps for preparing polysulfone membranes by phase inversion modification are as follows: Step 1: Prepare the casting solution. Add 40 wt% polysulfone to N-methylpyrrolidone (NMP) and mechanically stir to obtain a uniformly dispersed polysulfone solution. Then, add 0.5 wt% PEG to the polysulfone solution and stir at 300 r / min at room temperature until completely dissolved. Finally, add 70 wt% sulfur-doped nickel oxide to the solution and continue stirring for 24 hours until completely and uniformly dispersed.

[0087] Step 2, Degassing treatment of the casting solution. The casting solution is stirred at 70 r / min for 2.5 h to degas it.

[0088] Step 3, casting. Set the distance between the doctor blade and the glass membrane to 200 μm. Before casting, spread the casting solution on the front end of the doctor blade and slide the doctor blade at a uniform speed to spread the casting solution evenly on the surface of the glass membrane to form a liquid film.

[0089] Step 4, Pre-evaporation. The liquid film obtained by the scraper coating is left to stand in the air for 40 seconds for pre-evaporation.

[0090] Step 5: Immersion precipitate phase inversion membrane preparation. The liquid membrane is rapidly immersed in deionized water at 60°C and solidified into a membrane after 30 seconds. The membrane is then removed from the glass membrane surface to obtain a sulfur-doped nickel oxide modified polysulfone composite membrane material.

[0091] Step 6, membrane cleaning. Immerse the sulfur-doped nickel oxide-modified polysulfone composite membrane material in room temperature deionized water for 10 min, repeat 3 times.

[0092] To verify the structure and performance of the composite membrane of the present invention, the membranes prepared in Examples 1–5 were systematically characterized. Scanning electron microscopy (SEM) was used to observe the cross-sectional morphology and dopant particle distribution; pore size was statistically analyzed using image analysis software; porosity was determined using the wet-dry weight method; hydrophilicity was evaluated using a contact angle meter; Table 1 shows the thickness, pore size, and porosity of the composite membrane under different doctor blade spacings; ionic conductivity was tested using AC impedance spectroscopy; hydrogen permeability was determined using a pressure difference gas permeameter; Table 2 compares the performance of the composite membranes with different nickel oxide doping contents; Table 3 shows the effect of nickel oxide modified with different doping elements on the performance of the composite membrane.

[0093] Table 1: Thickness, pore size, and porosity of composite membranes under different doctor blade spacings

[0094] As the doctor blade spacing increases, the film thickness increases linearly, the pore size increases slightly but is always controlled within the range of 50–100 nm, the porosity remains above 70%, and the contact angle is below 35°, indicating that the film has high porosity and excellent hydrophilicity, and the process is well adjustable.

[0095] Table 2: Performance Comparison of Composite Films with Different Nickel Oxide Doping Content

[0096] With increasing nickel oxide doping content, the hydrophilicity of the membrane significantly improves (contact angle decreases), ionic conductivity increases, and hydrogen permeability decreases, indicating that nickel oxide doping effectively improves the conductivity and gas barrier properties of the membrane. Optimal performance is achieved at a content of 70 wt%, but considering mechanical strength, a range of 35–70 wt% is preferred.

[0097] Table 3: Effects of Nickel Oxide Modified by Different Doping Elements on the Performance of Composite Membranes

[0098] After doping with elements such as Cu, Zn, and S, the hydrophilicity, ionic conductivity, and porosity of the film are all better than those of undoped nickel oxide. Among them, S doping has the most obvious effect, possibly because the formation of Ni-S bonds improves surface energy and wettability.

[0099] In summary, in a water electrolysis hydrogen production device, hydrogen is generated at the cathode and oxygen at the anode, and the generated hydrogen and oxygen are separated by a membrane. The quality of the membrane in the water electrolysis hydrogen production device directly affects the overall gas purity and power consumption of the device. This invention proposes a nickel oxide-modified polysulfone composite membrane material for water electrolysis hydrogen production and its preparation method. This nickel oxide-doped material, through hydrothermal doping with cations such as copper, cesium, and zinc ions, can replace nickel ions to increase surface defects and oxygen vacancies, promoting the adsorption of hydroxide ions. Furthermore, through hydrothermal doping with nitrogen and sulfur elements, this material can form Ni-N and Ni-S bonds with nickel ions, increasing the surface energy of the material and improving particle wettability. Moreover, the hydrothermal synthesis method for nickel oxide doping allows high-temperature water vapor to form hydroxyl groups on its surface during the reaction, enhancing the material's hydrophilicity. The modified polysulfone membrane material prepared by phase inversion using this nickel oxide-doped material requires a small amount of addition and exhibits good stability due to the chemical bonding of the dopant. Furthermore, during the phase inversion preparation process, the small amount of nickel oxide added to the casting solution prevents agglomeration, resulting in a moderate viscosity and high porosity in the formed polysulfone membrane.

[0100] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A nickel oxide-modified polysulfone composite membrane material, characterized in that, It includes 35-70 wt% doped nickel oxide, 10-40 wt% polysulfone, and 0.5-30 wt% polyvinylpyrrolidone or 0.5-30 wt% polyethylene glycol.

2. A method for preparing a nickel oxide-modified polysulfone composite membrane material, characterized in that, include: Polysulfone is uniformly dispersed in N-methylpyrrolidone to obtain a polysulfone solution. PVP or PEG is added to the polysulfone solution and stirred until completely dissolved to obtain a mixed solution. Add the doped nickel oxide material to the mixed solution and stir until it is completely and uniformly dispersed to obtain the casting solution; then stir the casting solution for degassing. The casting solution is laid on the front end of the doctor blade, and the doctor blade is slid at a uniform speed to spread the casting solution evenly on the surface of the glass film to form a liquid film. The liquid membrane was pre-evaporated by being left to stand in the air. The pre-evaporated liquid membrane was then immersed in deionized water to solidify into a film. After the film was removed and cleaned, a nickel oxide-modified polysulfone composite membrane material was obtained.

3. The method for preparing a nickel oxide-modified polysulfone composite membrane material according to claim 2, characterized in that, The polysulfone content in the polysulfone solution is 10-40 wt%.

4. The method for preparing a nickel oxide-modified polysulfone composite membrane material according to claim 2, characterized in that, The content of PVP or PEG in the mixed solution is 0.5-30 wt%.

5. The method for preparing a nickel oxide-modified polysulfone composite membrane material according to claim 2, characterized in that, The content of the doped nickel oxide material in the casting solution is 35-70 wt%.

6. The method for preparing a nickel oxide-modified polysulfone composite membrane material according to claim 2, characterized in that, The casting solution is stirred at 40-70 r / min for 2-2.5 h to degas it.

7. The method for preparing a nickel oxide-modified polysulfone composite membrane material according to claim 2, characterized in that, When preparing the liquid membrane, the distance between the doctor blade and the glass membrane is 200-500 μm; the liquid membrane is pre-evaporated by standing in the air for 10-40 seconds.

8. The method for preparing a nickel oxide-modified polysulfone composite membrane material according to claim 2, characterized in that, The liquid membrane is rapidly immersed in deionized water at 15-60℃ and solidified into a film after 5-30 seconds. After being removed from the glass membrane surface, it is immersed in deionized water at room temperature for 3-10 minutes. This process is repeated 3 times to obtain a nickel oxide-modified polysulfone composite membrane material.

9. The method for preparing a nickel oxide-modified polysulfone composite membrane material according to claim 2, characterized in that, The doped nickel oxide is prepared by the following steps: Add one of the following aqueous solutions to an aqueous nickel nitrate solution: copper nitrate, zinc nitrate, cesium nitrate, urea, or thiourea, and mix thoroughly to obtain mixed solution A. After adding polyethylene glycol to mixed solution A and stirring, sodium hydroxide solution is slowly added dropwise to adjust the pH value to 12, and then stirred evenly to obtain mixed solution B. Mixed solution B undergoes a hydrothermal reaction to obtain a reaction solution. After the reaction solution is cooled to room temperature, it is washed and the precipitate is removed. After drying the precipitate to constant weight, it was subjected to constant temperature heat treatment and then naturally cooled to obtain doped nickel oxide.

10. The method for preparing a nickel oxide-modified polysulfone composite membrane material according to claim 9, characterized in that, The concentration of the nickel nitrate aqueous solution is 1.5-1.8 mol / L; add 3-10% of 1 mol / L copper nitrate, zinc nitrate, cesium nitrate, urea or thiourea to obtain mixed solution A; Add 1-3% polyethylene glycol to mixed solution A, stir for 20-40 min, then slowly add sodium hydroxide solution dropwise to adjust the pH to 12, and continue stirring for 20-40 min to obtain mixed solution B; Mixed solution B was subjected to hydrothermal reaction at 140-200℃ for 12-24 hours to obtain a reaction solution. After the reaction solution was cooled to room temperature, it was washed with deionized water and centrifuged to obtain the precipitate. After drying the precipitate to constant weight at 60-80℃, it is subjected to constant temperature heat treatment for 1-3 hours at a constant temperature of 200-400℃, and then naturally cooled to obtain doped nickel oxide.

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