Preparation method of electrode modified fiber membrane based on piezoelectric electric field effect

Abstract

The invention discloses a piezoelectric electric field effect-based preparation method of an electrode modified fiber membrane, which comprises the following steps: uniformly dispersing a polymer piezoelectric material and a functional filling material in an organic solvent to form a wall-mountable solution; placing a foam electrode on a spinning receiver, taking the mixed solution, carrying out electrostatic spinning, and uniformly coating the mixed solution on the foam electrode; and carrying out ultrasonic cleaning on the obtained electrode, and airing to obtain the electrode modified fiber membrane integrated with the electrode. The fiber membrane researched and developed by the invention is assembled with a commercial foam electrode by ingeniously utilizing the unique characteristics of a piezoelectric electric field, and a water molecule structure in an electrolyte is finely regulated and controlled, so that the excellent effect of remarkably reducing the overpotential of the electrode is achieved. The strategy not only enriches the material selection of the electrode modified fiber membrane, but also expands the application potential of the electrostatic spinning technology in the field of electrochemical water decomposition hydrogen production.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical water decomposition to produce hydrogen, and specifically is a method for preparing an electrode-modified fiber membrane based on the action of a piezoelectric field. Background Art

[0002] Electrolytic water splitting has become an efficient method for producing hydrogen, a clean, high-energy, and sustainable energy source. However, the efficiency of water splitting is mainly limited by the slow kinetics of the oxygen evolution reaction (OER). In industry, this process is usually carried out in a liquid alkaline electrolyte, so that non-precious metal catalysts can be used, in which OH - It is the main source of oxygen. - The efficient transport and adsorption of OH are crucial to OER kinetics. Although many studies have adjusted the nanostructure, defects, and atomic doping of OER catalysts to optimize adsorption energy and increase active sites, their activity and stability are still far behind the level required for widespread application, such as CN109621959A and CN114400336A. Therefore, it is necessary to develop other strategies to accelerate OH - Adsorption.

[0003] Recently, for hydrogen evolution reactions in neutral and alkaline environments with H2O as the main reactant, researchers have realized that interfacial water with weakened hydrogen bonding networks can enhance the migration and adsorption of H2O on the catalyst surface. - It is the main reactant of alkaline OER, but H2O molecules will react with OH - A dissolution shell forms around it, and a thinner hydration shell may accelerate the OH - Typically, achieving interfacial water structures that are weakly hydrogen bonded relies on catalysts with highly oxophilic components that can attract H2O, but this often results in excessive H2O occupation of active sites, while OH - should be adsorbed on the active sites.

[0004] Based on this, the present invention innovatively introduces a variety of functional filling materials into the electrospinning solution to construct and prepare a high-efficiency fiber membrane modified electrode to significantly improve the efficiency and stability of electrochemical water decomposition to produce hydrogen. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing an electrode modified fiber membrane based on the action of a piezoelectric field, which restructures the water structure in the electrolyte by a piezoelectric field and optimizes the OH - Adsorption and transport.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A method for preparing an electrode-modified fiber membrane comprises the following steps: S1: Add polymer piezoelectric material and functional filling material into organic solvent and stir at high temperature until a uniform solution is formed that can be attached to the wall; S2: placing the foam electrode on a spinning receiver, and electrospinning the solution obtained in step S1 to evenly coat the foam electrode; S3: ultrasonically clean the electrode obtained in step S2, and after drying, obtain an electrode-modified fiber membrane integrated with the electrode to enhance the electrocatalytic oxygen evolution performance based on the action of a piezoelectric field.

[0007] Preferably, the polymer piezoelectric material in step S1 is polyvinylidene fluoride, polyvinylidene fluoride-chlorotrifluoroethylene copolymer or polyvinylidene fluoride-hexafluoropropylene copolymer.

[0008] Preferably, the mass of the polymer piezoelectric material in step S1 accounts for 10-20% of the organic solvent.

[0009] Preferably, the functional filling material in step S1 is barium titanate, lead zirconate titanate, kaolin, cobalt powder, cobalt trioxide or graphene oxide.

[0010] Preferably, the mass ratio of the functional filling material to the polymer piezoelectric material in step S1 is 1:1 or 1:2.

[0011] Preferably, the organic solvent in step S1 is acetone or N, N-dimethylformamide.

[0012] Preferably, the voltage of electrospinning in step S2 is 15-20 kV.

[0013] Preferably, the injection rate of the electrospinning solution in step S2 is 20-30 μL / min.

[0014] Preferably, the electrospinning time in step S2 is 15-30 min.

[0015] Preferably, the ultrasonic cleaning solution in step S3 is a solution of ethanol and deionized water.

[0016] Preferably, the ultrasonic cleaning time in step S3 is 10-30 min.

[0017] The electrode modified fiber membrane prepared by the above method is used as a catalyst, and the catalyst is used for electrocatalytic water decomposition of oxygen.

[0018] The present invention innovatively introduces a variety of functional filling materials into the electrospinning solution. These materials include barium titanate, lead zirconate titanate, kaolin, cobalt powder, cobalt trioxide and graphene oxide. Each material has unique physical and chemical properties and can play an important role in the electrochemical water decomposition process to produce hydrogen: barium titanate, as a typical piezoelectric material, can produce a piezoelectric effect under the action of an electric field, reorganize the structure of water in the electrolyte, optimize the transmission and adsorption of OH⁻, and thus improve the electrocatalytic oxygen evolution performance; lead zirconate titanate has excellent piezoelectric properties and a high dielectric constant, which can enhance the electric field strength at the electrode / electrolyte interface, promote the dissociation of water molecules and the generation of oxygen; kaolin, as a natural clay mineral, has a unique layered structure and adsorption properties, which can improve the corrosion resistance of the electrode. The materials exhibit excellent electrical conductivity and stability, while also providing abundant active sites. Cobalt powder and cobalt tetroxide possess excellent magnetic properties and can interact with nickel foam to form a local magnetic field. This magnetic field can influence the orientation and movement of water molecules in the electrolyte, optimizing the water structure and thus helping to improve the efficiency of the oxygen evolution reaction (OER). Graphene oxide has excellent electrical conductivity and a large specific surface area. Its electrical conductivity can reduce charge transfer resistance, thereby accelerating the rate of electrochemical reactions. Its large specific surface area provides more adsorption sites for reactants, increasing the contact area between reactants and the catalyst and facilitating the reaction. By combining these functional materials with the synergistic effect of a piezoelectric field, the present invention provides a highly efficient electrode-modified fiber membrane that significantly improves the efficiency and stability of electrochemical water splitting for hydrogen production. This strategy not only enriches the material selection for electrode-modified fiber membranes but also expands the application potential of electrospinning technology in the field of electrochemical water splitting for hydrogen production.

[0019] In the present invention, the developed fiber membrane cleverly uses the unique characteristics of the piezoelectric field and is assembled with a commercial foam electrode to finely control the structure of water molecules in the electrolyte, thereby achieving the excellent effect of significantly reducing the electrode overpotential. During the electrocatalytic process, there is no need to add other forces to the electrode. When the bubbles generated by itself burst, cavitation force is generated. The cavitation force acts on the polymer piezoelectric material, enabling it to more effectively control the structure of water molecules in the electrolyte, optimize the arrangement and distribution of water molecules, weaken the hydrogen bond network, and thus reduce the electrode overpotential, thereby improving the efficiency and performance of the electrocatalytic reaction. At the same time, it can also improve the interfacial stability between the electrode and the electrolyte, enhance the charge transfer efficiency, and promote the continued progress of the electrocatalytic reaction.

[0020] Beneficial effects: Compared with traditional electrolytes, the electrode modified fiber membrane based on the piezoelectric field of the present invention can improve the performance of the electrocatalytic water-oxygen separation reaction and significantly reduce the electrode overpotential. Compared with the modification of the catalyst, the present invention uses the piezoelectric field to regulate the water structure in the electrolyte and optimize the reaction of the reactant OH -The transport and adsorption of the electrocatalytic water splitting can further improve the efficiency. In addition, the preparation process of the present invention is simple, low-cost, suitable for batch application, and has broad application prospects in the fields of electrocatalysis and photoelectrocatalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the SEM image of the nickel foam electrode with integrated piezoelectric fiber membrane prepared in Example 1. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention will be described in detail below with reference to the examples. It should be understood that the following examples are provided for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art may make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0023] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0024] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0025] Example 1 Preparation of spinning solution: Weigh 0.5 g of polyvinylidene fluoride and 0.5 g of barium titanate, place them in 5 g of acetone solvent, and stir at high temperature until a uniform solution that can hang on the wall is formed.

[0026] Preparation of electrospinning fiber membrane: The voltage of the high-voltage power supply was set to 15 kV, the solution injection rate was 20 μL / min, the foam electrode was attached to the spinning receiver, and electrospinning was performed for 15 min to obtain a piezoelectric fiber membrane integrated on the electrode.

[0027] Cleaning and drying of electrospun fiber membrane: The electrode of the integrated piezoelectric fiber membrane was placed in a solution of ethanol and deionized water for ultrasonic cleaning for 10 min, and then dried.

[0028] Example 2 Preparation of spinning solution: Weigh 1.0 g of polyvinylidene fluoride-chlorotrifluoroethylene copolymer and 0.5 g of lead zirconate titanate, place them in 5 g of N, N-dimethylformamide solvent, and stir at high temperature until a uniform solution that can be attached to the wall is formed.

[0029] Preparation of electrospinning fiber membrane: The voltage of the high-voltage power supply was set to 20 kV, the solution injection rate was 30 μL / min, the foam electrode was attached to the spinning receiver, and electrospinning was performed for 30 min to obtain a piezoelectric fiber membrane integrated on the electrode.

[0030] Cleaning and drying of electrospun fiber membrane: The electrode of the integrated piezoelectric fiber membrane was placed in a solution of ethanol and deionized water for ultrasonic cleaning for 30 min and then dried.

[0031] Example 3 Preparation of spinning solution: Weigh 1.0 g of polyvinylidene fluoride-hexafluoropropylene copolymer and 0.5 g of kaolin, place them in 5 g of N, N-dimethylformamide solvent, and stir at high temperature until a uniform solution that can be attached to the wall is formed.

[0032] Preparation of electrospinning fiber membrane: The voltage of the high-voltage power supply was set to 18 kV, the solution injection rate was 30 μL / min, the foam electrode was attached to the spinning receiver, and electrospinning was performed for 30 min to obtain a piezoelectric fiber membrane integrated on the electrode.

[0033] Cleaning and drying of electrospun fiber membrane: The electrode of the integrated piezoelectric fiber membrane was placed in a solution of ethanol and deionized water for ultrasonic cleaning for 30 min and then dried.

[0034] Example 4 Preparation of spinning solution: Weigh 0.5 g polyvinylidene fluoride and 0.25 g graphene oxide, place them in 5 g N, N-dimethylformamide solvent, and stir at high temperature until a uniform solution that can be attached to the wall is formed.

[0035] Preparation of electrospinning fiber membrane: The voltage of the high-voltage power supply was set to 18 kV, the solution injection rate was 30 μL / min, the foam electrode was attached to the spinning receiver, and electrospinning was performed for 30 min to obtain a piezoelectric fiber membrane integrated on the electrode.

[0036] Cleaning and drying of electrospun fiber membrane: The electrode of the integrated piezoelectric fiber membrane was placed in a solution of ethanol and deionized water for ultrasonic cleaning for 30 min and then dried.

[0037] Example 5 Preparation of spinning solution: Weigh 0.5 g of polyvinylidene fluoride and 0.25 g of cobalt powder, place them in 5 g of N, N-dimethylformamide solvent, and stir at high temperature until a uniform solution that can be attached to the wall is formed.

[0038] Preparation of electrospinning fiber membrane: The voltage of the high-voltage power supply was set to 15 kV, the solution injection rate was 20 μL / min, the foam electrode was attached to the spinning receiver, and electrospinning was performed for 20 min to obtain a piezoelectric fiber membrane integrated on the electrode.

[0039] Cleaning and drying of electrospun fiber membrane: The electrode of the integrated piezoelectric fiber membrane was placed in a solution of ethanol and deionized water for ultrasonic cleaning for 30 min and then dried.

[0040] Example 6 Preparation of spinning solution: Weigh 0.5g polyvinylidene fluoride and 0.25g cobalt tetroxide, place them in 5g N, N-dimethylformamide solvent, and stir at high temperature until a uniform solution that can be attached to the wall is formed.

[0041] Preparation of electrospinning fiber membrane: The voltage of the high-voltage power supply was set to 18 kV, the solution injection rate was 30 μL / min, the foam electrode was attached to the spinning receiver, and electrospinning was performed for 30 min to obtain a piezoelectric fiber membrane integrated on the electrode.

[0042] Cleaning and drying of electrospun fiber membrane: The electrode of the integrated piezoelectric fiber membrane was placed in a solution of ethanol and deionized water for ultrasonic cleaning for 30 min and then dried.

[0043] In Example 1-6, nickel foam was used as the test electrode and the electrolyte was 1M KOH solution. After ultrasonic treatment for 2 minutes, the electrocatalytic oxygen evolution performance test was shown in the following table: ; As can be seen from the above table, after the alkaline electrolytes in Examples 1-6 were regulated by the piezoelectric field of different electrode-modified fiber membranes, the electrocatalytic water splitting performance of the electrodes was significantly improved.

Claims

1. A method for preparing an electrode-modified fiber membrane based on piezoelectric field action, characterized in that: The following steps are involved: S1: Adding polymer piezoelectric material and functional filling material into organic solvent and stirring to obtain a uniform solution that can be coated on the wall; S2: placing the foam electrode on a spinning receiver, and electrospinning the solution obtained in step S1 to evenly coat the foam electrode; S3: ultrasonically clean the electrode obtained in step S2, and dry it to obtain an electrode-modified fiber membrane integrated with the electrode.

2. The preparation method according to claim 1, characterized in that The polymer piezoelectric material in step S1 is polyvinylidene fluoride, polyvinylidene fluoride-chlorotrifluoroethylene copolymer or polyvinylidene fluoride-hexafluoropropylene copolymer.

3. The preparation method according to claim 1, characterized in that The mass of the polymer piezoelectric material described in step S1 accounts for 10-20% of the organic solvent.

4. The preparation method according to claim 1, characterized in that The functional filling material in step S1 is barium titanate, lead zirconate titanate, kaolin, cobalt powder, cobalt trioxide or graphene oxide.

5. The preparation method according to claim 1, wherein: The mass ratio of the functional filling material to the polymer piezoelectric material in step S1 is 1:1 or 1:

2.

6. The preparation method according to claim 1, characterized in that The organic solvent in step S1 is acetone or N,N-dimethylformamide.

7. The preparation method according to claim 1, wherein: In step S2, the electrospinning voltage is 15-20 kV, the injection rate of the electrospinning solution is 20-30 μL / min, and the electrospinning time is 15-30 min.

8. The preparation method according to claim 1, wherein: The ultrasonic cleaning solution described in step S3 is a solution of ethanol and deionized water.

9. The preparation method according to claim 1, characterized in that The ultrasonic cleaning time in step S3 is 10-30 min.

10. Use of the electrode modified fiber membrane prepared by the method according to any one of claims 1 to 9 as a catalyst, characterized in that: The catalyst is used for electrocatalytic water separation to produce oxygen.

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