A polydimethylsiloxane nanoparticle-modified hydrogen evolution electrode for water electrolysis, its preparation method and application

Abstract

This invention discloses a polydimethylsiloxane nanoparticle-modified water electrolysis hydrogen evolution electrode, its preparation method, and its application, belonging to the field of interface control of water electrolysis electrodes. The preparation method of the electrode includes: (1) dispersing and mixing polydimethylsiloxane alkyl body and crosslinking agent in an organic solvent to obtain an organic phase solution; then dissolving an emulsifier in water to obtain an aqueous phase solution; then adding the aqueous phase solution to the organic phase solution and mixing to obtain an aqueous dispersion of polydimethylsiloxane nanoparticles; (2) diluting the above aqueous dispersion with water to obtain a diluted dispersion of polydimethylsiloxane nanoparticles; (3) fixing the water electrolysis hydrogen evolution electrode on a heating device, spraying the above diluted dispersion onto the electrode surface, and then drying it to obtain the electrode. This invention performs discontinuous modification on the electrode surface, which can reduce the retention of bubbles on the electrode surface without forming a continuous hydrophobic film, thereby reducing the reaction overpotential under high current density and improving the electrode's operational stability.

Description

Technical Field

[0001] This invention belongs to the field of interface control of water electrolysis electrodes, and particularly relates to a hydrogen evolution electrode for water electrolysis modified with polydimethylsiloxane nanoparticles, its preparation method and application. Background Technology

[0002] Hydrogen, with its high specific energy density and clean, carbon-free characteristics, is considered an important energy carrier in future sustainable energy systems. Compared to traditional hydrogen production technologies, anion exchange membrane (AEM) water electrolysis technology utilizes renewable energy to drive electrochemical water splitting for hydrogen production. It boasts advantages such as lower cost, higher device integration, and suitability for efficient hydrogen production, making it highly promising. During actual operation of an AEM electrolyzer, hydrogen and oxygen bubbles continuously precipitate on the cathode and anode surfaces. If these bubbles cannot desorb in time and instead remain on the electrode surfaces, forming a "bubble blanket," they will obscure active sites, increase overpotential, and reduce electrolysis efficiency, thus affecting the long-term operational stability of the device.

[0003] Currently, there are technical solutions for addressing the problem of bubble desorption on electrode surfaces, including external field-assisted control, surface structure design, and wettability control. However, these solutions still suffer from high energy consumption, complex fabrication processes, and insufficient adaptability to different substrates.

[0004] Therefore, developing an electrode interface modification method that is simple to prepare, highly adaptable, and can promote rapid bubble desorption without significantly sacrificing catalytic activity is of great application value. Summary of the Invention

[0005] Objectives of the Invention: The first objective of this invention is to provide a polydimethylsiloxane nanoparticle-modified hydrogen evolution electrode for water electrolysis that can promote rapid desorption of bubbles, improve the hydrogen evolution performance of the electrode, and thus improve the operational stability of the electrode. The second objective of this invention is to provide a method for preparing the above-mentioned electrode. The third objective of this invention is to provide applications of the above-mentioned electrode.

[0006] Technical solution: The electrolytic hydrogen evolution electrode modified with polydimethylsiloxane nanoparticles provided by the present invention is a water electrolysis electrode on which polydimethylsiloxane nanoparticles are loaded.

[0007] Furthermore, the average particle size of the polydimethylsiloxane nanoparticles is 18-20 nm.

[0008] The preparation method of the above-mentioned polydimethylsiloxane nanoparticle-modified water electrolysis hydrogen evolution electrode includes the following steps: (1) First, the polydimethylsiloxane body and crosslinking agent are dispersed and mixed in an organic solvent to obtain an organic phase solution; then the emulsifier is dissolved in water to obtain an aqueous phase solution; then the aqueous phase solution is added to the organic phase solution and mixed to obtain an aqueous dispersion of polydimethylsiloxane nanoparticles; (2) The aqueous dispersion of polydimethylsiloxane nanoparticles was diluted with water to obtain a diluted dispersion of polydimethylsiloxane nanoparticles. (3) Fix the hydrogen evolution electrode of water electrolysis on the heating device, spray the diluted dispersion of polydimethylsiloxane nanoparticles onto the electrode surface, and then dry it to obtain the hydrogen evolution electrode of water electrolysis modified with polydimethylsiloxane nanoparticles.

[0009] Further, in step (1), the ratio of the polydimethylsiloxane, crosslinking agent and organic solvent is 50mg:5mg:0.8-1.0mL; the crosslinking agent is methylhydrosiloxane; and the organic solvent is tetrahydrofuran.

[0010] Further, the emulsifier is Span 80 and Tween 80 in a mass ratio of 5-5.4:4-4.6; the emulsifier to water ratio is 0.9-1.0g:10-12mL.

[0011] Furthermore, in step (2), the dilution factor is 60-80 times the original volume.

[0012] Further, in step (3), the heating device is set to a temperature of 50-60℃, and the drying time is 10-20 min; the amount of the polydimethylsiloxane nanoparticle dilution dispersion is related to the electrode area by the amount of each nanoparticle per 1 cm² area. 2 The amount of the electrode polydimethylsiloxane nanoparticle dilution dispersion used is 4-6 mL.

[0013] The above-mentioned polydimethylsiloxane nanoparticle-modified hydrogen evolution electrode for water electrolysis is applied in the field of hydrogen production by water electrolysis.

[0014] Invention principle: Polydimethylsiloxane nanoparticles, as a highly flexible material, can adhere well to rough, porous and fibrous substrate surfaces, and also have excellent properties such as low surface energy, good chemical stability and excellent processability. This invention introduces discretely distributed polydimethylsiloxane nanoparticles on the electrode surface to construct a low surface energy heterogeneous interface, regulate the desorption behavior of bubbles on the electrode surface during water electrolysis, thereby reducing the reaction overpotential and improving the electrode's operational stability.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following significant effects: (1) The preparation method of polydimethylsiloxane nanoparticles used in the present invention has mild reaction conditions, simple process, no need for high temperature and high pressure treatment, and less organic solvent is used, which has good process scalability; (2) The present invention has a certain universality of method, not for a specific electrode, but applicable to a variety of water electrolysis hydrogen evolution electrodes, reducing reaction overpotential and improving electrocatalytic performance; (3) The present invention performs discontinuous modification on the electrode surface, which can reduce the retention of bubbles on the electrode surface without forming a continuous hydrophobic film, thereby reducing the reaction overpotential under high current density and improving the electrode operation stability. Attached Figure Description

[0016] Figure 1 SEM image of the polydimethylsiloxane nanoparticles prepared in Example 1; Figure 2 The particle size distribution diagram of the polydimethylsiloxane nanoparticles prepared in Example 1 is shown. Figure 3 The graph shows a comparison of the hydrogen evolution performance of the Pt / C carbon paper electrode modified with polydimethylsiloxane nanoparticles prepared in Example 1 and the pure Pt / C carbon paper electrode in Comparative Example 1. Figure 4 The graph shows a comparison of the hydrogen evolution performance of the Pt / C carbon paper electrode modified with polydimethylsiloxane nanoparticles prepared in Example 2 and the pure Pt / C carbon paper electrode in Comparative Example 1. Figure 5 The graph shows a comparison of the hydrogen evolution performance of the Pt / C carbon paper electrode modified with polydimethylsiloxane nanoparticles prepared in Example 3 and the pure Pt / C carbon paper electrode in Comparative Example 1. Figure 6 Comparison of hydrogen evolution performance of Pt / C carbon paper electrodes modified with polydimethylsiloxane nanoparticles prepared in Examples 1-3; Figure 7 The graph shows a comparison of the operational stability of the Pt / C carbon paper electrode modified with polydimethylsiloxane nanoparticles prepared in Example 2 and the pure Pt / C carbon paper electrode in Comparative Example 1 in an electrolytic cell. Figure 8 The image shows a comparison of the average desorption particle size of hydrogen bubbles on the surface of the Pt / C carbon paper electrode modified with polydimethylsiloxane nanoparticles prepared in Example 2 and the pure Pt / C carbon paper electrode in Comparative Example 1. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings.

[0018] Example 1: The polydimethylsiloxane nanoparticle-modified hydrogen evolution electrode for water electrolysis provided in this example is prepared by loading polydimethylsiloxane nanoparticles onto the electrode surface, as follows: (1) Take 50 mg of polydimethylsiloxane body and 5 mg of methylhydrosiloxane crosslinking agent and dissolve them in 0.8 mL of tetrahydrofuran. Stir well to obtain an organic phase solution for later use. Then take 0.5 g of Span 80 and 0.4 g of Tween 80 and dissolve them in 10 mL of deionized water. Sonicate them to fully dissolve them to obtain an aqueous phase solution. Then add the aqueous phase solution to the organic phase solution and sonicate for 1 h at a temperature below 30 °C to ensure that the organic phase solution is fully dispersed in the aqueous phase solution. Finally, stir at low speed for 24 h at room temperature to obtain an aqueous dispersion of polydimethylsiloxane nanoparticles. (2) Take 1 mL of the dispersion obtained in step (1) and add 59 mL of deionized water to obtain a diluted aqueous dispersion of polydimethylsiloxane nanoparticles. (3) Place the electrode sheet (carbon paper loaded with Pt / C catalyst (1 cm × 1 cm, Pt: 1 mg cm)) -2 The electrode sheet was fixed on the heating stage, and 4 mL of the polydimethylsiloxane nanoparticle aqueous dispersion obtained in step (2) was sprayed onto the surface of the electrode sheet using an air spray gun. The electrode sheet was then dried on the heating stage for 15 min to obtain the polydimethylsiloxane nanoparticle modified electrode sheet.

[0019] Example 2: The polydimethylsiloxane nanoparticle-modified hydrogen evolution electrode for water electrolysis provided in this example is prepared by loading polydimethylsiloxane nanoparticles onto the electrode surface, as follows: (1) Take 50 mg of polydimethylsiloxane body and 5 mg of methylhydrosiloxane crosslinking agent and dissolve them in 0.8 mL of tetrahydrofuran. Stir well to obtain an organic phase solution for later use. Then take 0.5 g of Span 80 and 0.4 g of Tween 80 and dissolve them in 10 mL of deionized water. Sonicate them to fully dissolve them to obtain an aqueous phase solution. Then add the aqueous phase solution to the organic phase solution and sonicate for 1 h at a temperature below 30 °C to ensure that the organic phase solution is fully dispersed in the aqueous phase solution. Finally, stir at low speed for 24 h at room temperature to obtain an aqueous dispersion of polydimethylsiloxane nanoparticles. (2) Take 1 mL of the dispersion obtained in step (1) and add 69 mL of deionized water to obtain a diluted aqueous dispersion of polydimethylsiloxane nanoparticles. (3) Place the electrode sheet (carbon paper loaded with Pt / C catalyst (1 cm × 1 cm, Pt: 1 mg cm)) -2The electrode was fixed on the heating stage, and 4 mL of the polydimethylsiloxane nanoparticle aqueous dispersion obtained in step (2) was sprayed onto the electrode surface using an air spray gun. The electrode was then dried on the heating stage for 15 min to obtain the polydimethylsiloxane nanoparticle modified electrode.

[0020] Example 3: The polydimethylsiloxane nanoparticle-modified water electrolysis hydrogen evolution electrode provided in this example is prepared by loading polydimethylsiloxane nanoparticles onto the electrode surface, as follows: (1) Take 50 mg of polydimethylsiloxane body and 5 mg of methylhydrosiloxane crosslinking agent and dissolve them in 0.8 mL of tetrahydrofuran. Stir well to obtain an organic phase solution for later use. Then take 0.5 g of Span 80 and 0.4 g of Tween 80 and dissolve them in 10 mL of deionized water. Sonicate them to fully dissolve them to obtain an aqueous phase solution. Then add the aqueous phase solution to the organic phase solution and sonicate for 1 h at a temperature below 30 °C to ensure that the organic phase solution is fully dispersed in the aqueous phase solution. Finally, stir at low speed for 24 h at room temperature to obtain an aqueous dispersion of polydimethylsiloxane nanoparticles. (2) Take 1 mL of the dispersion obtained in step (1) and add 79 mL of deionized water to obtain a diluted aqueous dispersion of polydimethylsiloxane nanoparticles. (3) Place the electrode sheet (carbon paper loaded with Pt / C catalyst (1 cm × 1 cm, Pt: 1 mg cm)) -2 The electrode was fixed on the heating stage, and 4 mL of the polydimethylsiloxane nanoparticle aqueous dispersion obtained in step (2) was sprayed onto the electrode surface using an air spray gun. The electrode was then dried on the heating stage for 15 min to obtain the polydimethylsiloxane nanoparticle modified electrode.

[0021] Comparative Example 1: Pt / C carbon paper electrode with unmodified polydimethylsiloxane nanoparticles.

[0022] The polydimethylsiloxane nanoparticles synthesized in Example 1 were characterized, and the results are shown in the figure. Figures 1-2 . Figure 1 The images show polydimethylsiloxane nanoparticles under high-magnification surface scanning electron microscopy, with the nanoparticles distributed in a discrete particulate manner. Figure 2 The results of DLS particle size distribution testing show that the average particle size of polydimethylsiloxane nanoparticles is 18.90 nm.

[0023] Electrolysis performance tests were conducted on Examples 1-3 and Comparative Example 1, and the results are shown in the figure. Figures 3-5 .Depend on Figures 3-5 It can be seen that, compared with the unmodified electrode of Comparative Example 1, the polydimethylsiloxane nanoparticle modified electrodes of Examples 1, 2, and 3 show better performance at 1.0 A cm⁻¹. -2The voltages decreased by 40mV, 70mV and 50mV respectively, indicating that appropriate nanoparticle modification can effectively reduce electrolysis energy consumption under high current density.

[0024] Depend on Figure 6 It can be seen that, comparing Examples 1, 2 and 3, Example 2 exhibits the best hydrogen evolution performance in water electrolysis, indicating that the presence of polydimethylsiloxane nanoparticle modification is the optimal spraying concentration. When the concentration is too high, the nanoparticles may excessively cover the active sites on the catalyst surface, greatly reducing the electrochemical active area. When the concentration is too low, it cannot effectively regulate the behavior of bubbles.

[0025] Constant current stability tests were performed on Example 2 and Comparative Example 1, and the results are shown in [the table below]. Figure 7 .Depend on Figure 7 As can be seen from the constant current test results, the modified electrode prepared in Example 2 exhibits a smaller voltage rise and a more stable voltage response compared to the unmodified control, indicating that the modified electrode has better operational stability.

[0026] The bubble desorption size in the water electrolysis process of Example 2 and Comparative Example 1 was statistically analyzed, and the results are shown in the figure. Figure 8 .Depend on Figure 8 It can be seen that, compared with the unmodified Comparative Example 1, the average desorption diameter of bubbles in the modified electrode prepared in Example 2 decreased from 55.90 μm to 32.65 μm, indicating that the modification of polydimethylsiloxane nanoparticles can promote bubble desorption.

Claims

1. A water electrolysis hydrogen evolution electrode modified with polydimethylsiloxane nanoparticles, characterized in that, Polydimethylsiloxane nanoparticles are loaded onto the electrode surface.

2. The electrode according to claim 1, characterized in that, The average particle size of the polydimethylsiloxane nanoparticles is 18-20 nm.

3. A method for preparing a water electrolysis hydrogen evolution electrode modified with polydimethylsiloxane nanoparticles as described in claim 1, characterized in that, Includes the following steps: (1) First, the polydimethylsiloxane body and crosslinking agent are dispersed and mixed in an organic solvent to obtain an organic phase solution; then the emulsifier is dissolved in water to obtain an aqueous phase solution; then the aqueous phase solution is added to the organic phase solution and mixed to obtain an aqueous dispersion of polydimethylsiloxane nanoparticles; (2) The aqueous dispersion of polydimethylsiloxane nanoparticles was diluted with water to obtain a diluted dispersion of polydimethylsiloxane nanoparticles. (3) Fix the hydrogen evolution electrode of water electrolysis on the heating device, spray the diluted dispersion of polydimethylsiloxane nanoparticles onto the electrode surface, and then dry it to obtain the hydrogen evolution electrode of water electrolysis modified with polydimethylsiloxane nanoparticles.

4. The preparation method according to claim 3, characterized in that, In step (1), the ratio of the polydimethylsiloxane, crosslinking agent and organic solvent is 50mg:5mg:0.8-1.0mL.

5. The preparation method according to claim 3, characterized in that, In step (1), the crosslinking agent is methylhydrosiloxane; the organic solvent is tetrahydrofuran.

6. The preparation method according to claim 3, characterized in that, In step (1), the emulsifier is Span 80 and Tween 80 in a mass ratio of 5-5.4:4-4.6; the emulsifier to water ratio is 0.9-1.0g:10-12mL.

7. The preparation method according to claim 3, characterized in that, In step (2), the dilution factor is 60-80 times the original volume.

8. The preparation method according to claim 3, characterized in that, In step (3), the heating device is set to a temperature of 50-60℃.

9. The preparation method according to claim 3, characterized in that, In step (3), the amount of the polydimethylsiloxane nanoparticle dilution dispersion used is related to the electrode area as follows: per 1 cm² 2 The amount of the electrode polydimethylsiloxane nanoparticle dilution dispersion used is 4-6 mL.

10. The application of the polydimethylsiloxane nanoparticle-modified hydrogen evolution electrode for water electrolysis as described in claim 1 in the field of hydrogen production by water electrolysis.

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