A bubble separation device and a preparation method and application thereof

Abstract

The application provides a bubble separation device, which is connected with a working electrode of hydrogen production by electrolysis of water, and is applied to separation and directional regulation of bubbles generated on the surface of the working electrode. In the application, a triangular area between adjacent through grooves is used to form a bubble separation channel, the bubble separation channel can generate an asymmetric Laplace pressure gradient, so as to drive the bubbles to move in a specific direction. Meanwhile, the super-hydrophobic-lubricating composite coating has excellent gas affinity and lubricating performance, not only provides good bubble adsorption conditions, but also reduces the frictional resistance of the bubbles when moving on the surface through the surface lubricating effect, so that the bubbles can quickly realize directional regulation and transfer. The hydrogen bubbles generated on the surface of the working electrode tend to move to the surface of the super-hydrophobic-lubricating composite coating and transfer to the bubble separation channel, by using the asymmetry of the bubble separation channel, through a self-driven "moving-merging-moving" circulation process, the bubbles are directionally moved and efficiently collected to a target position.

Description

Technical Field

[0001] This invention relates to the field of water electrolysis for hydrogen production, specifically to a bubble separation device, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Hydrogen, with its high energy density and zero carbon emissions, is widely recognized as a crucial carrier for promoting sustainable energy transformation and is considered one of the most promising clean energy sources of the 21st century. Water electrolysis for hydrogen production has become a key technology in the field due to its ease of operation and pure products. Water electrolysis decomposes water into hydrogen and oxygen through the cathode hydrogen evolution reaction (HER) and the anodic oxygen evolution reaction (OER). However, the uncontrollable behavior of bubbles is a key factor limiting electrolysis efficiency. During electrolysis, the generation and accumulation of interfacial bubbles can cover the active sites of the electrodes, hindering electrolyte mass transfer and leading to increased local overpotential and uneven current distribution. This not only exacerbates electrode corrosion and localized heating but also increases the heat dissipation burden and reduces the purity of the hydrogen. Furthermore, the stress generated during bubble desorption can cause surface cracks and spalling on the electrodes, thus affecting electrode lifespan. Although moderate bubble movement can promote convection and enhance mass transfer, excessive bubble accumulation can significantly affect local gas supersaturation, increase solution resistance, and induce polarization effects, leading to a decline in overall electrolysis performance. Therefore, it is imperative to seek methods for targeted control of bubbles during water electrolysis and to develop efficient bubble removal technology. Summary of the Invention

[0004] To overcome the above problems, the present invention provides a bubble separation device, its preparation method and application.

[0005] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a bubble separation device, including a base plate, one end of which is provided with a plurality of interconnected through grooves, the through grooves extending in a divergent manner toward the other end of the base plate; a bubble separation channel is formed between adjacent through grooves, and a superhydrophobic-lubricating composite coating is provided on the surface of the base plate where the bubble separation channel is located.

[0007] A second aspect of the present invention provides a method for preparing the bubble separation device described in the first aspect, comprising the following steps:

[0008] The design grooves are etched into the base plate. After washing and drying, a superhydrophobic coating is applied to the surface of the base plate between adjacent grooves. After drying, the entire base plate is immersed in lubricating fluid and dried again to form the bubble separation device.

[0009] A third aspect of the present invention provides a system for producing hydrogen by electrolysis of water, comprising the bubble separation device described in the first aspect.

[0010] The beneficial effects of this invention are as follows:

[0011] (1) This invention provides a bubble separation device, which is connected to the working electrode for hydrogen production via water electrolysis, and is applied to the separation and directional control of bubbles generated on the surface of the working electrode. In this invention, a bubble separation channel is formed using a triangular region between adjacent channels. This bubble separation channel can generate an asymmetric Laplace pressure gradient, thereby driving the bubbles to move in a specific direction. Simultaneously, the superhydrophobic-lubricating composite coating possesses excellent gas affinity and lubrication properties, providing not only good bubble adsorption conditions but also reducing the frictional resistance of bubbles during surface movement through surface lubrication, ensuring that bubbles can be rapidly directionally controlled and transferred. Hydrogen bubbles generated on the surface of the working electrode tend to move towards the surface of the superhydrophobic-lubricating composite coating and transfer to the bubble separation channel. Utilizing the asymmetry of the bubble separation channel, they are efficiently collected to the target location through a self-driven "movement-merging-re-movement" cyclic process.

[0012] (2) The bubble separation device provided by this invention forms a bubble separation channel through a triangular region between adjacent channels. Combined with the superhydrophobic surface and smooth, low-friction properties, it achieves efficient directional control and collection of bubbles, solving problems such as electrode active site coverage, electrolyte mass transfer obstruction, and overpotential increase caused by bubble accumulation during water electrolysis for hydrogen production. This significantly improves hydrogen production efficiency, reduces energy consumption in the electrolysis process, and provides an efficient and stable technical solution for large-scale water electrolysis for hydrogen production.

[0013] (3) The triangular area between adjacent channels forms a bubble separation channel, which significantly expands the bubble movement path and controllable area, and improves the bubble detachment efficiency. Attached Figure Description

[0014] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0015] Figure 1 This is a schematic diagram of the bubble separation device in this invention; wherein, 1-bottom plate, 2-through groove, 3-bubble separation channel;

[0016] Figure 2A schematic diagram of a system for producing hydrogen by water electrolysis; wherein, 4-electrochemical workstation, 5-electrolyte, 6-auxiliary electrode, 7-reference electrode, 8-bubble separation device, 9-electrode clamp, 10-working electrode, 11-wire.

[0017] Figure 3 Contact angle;

[0018] Figure 4 This is a schematic diagram of the bubble movement process. Detailed Implementation

[0019] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0020] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0021] A first typical embodiment of the present invention provides a bubble separation device, including a base plate, one end of which is provided with a plurality of interconnected through grooves, the through grooves extending in a divergent manner toward the other end of the base plate; a bubble separation channel is formed between adjacent through grooves, and a superhydrophobic-lubricating composite coating is provided on the surface of the base plate where the bubble separation channel is located.

[0022] In one or more embodiments, the base plate is made of polymethyl methacrylate (PMMA).

[0023] In one or more embodiments, the included angle between adjacent through slots is 2° to 8°.

[0024] In one or more embodiments, the width of the through groove is 0.5 to 2 mm.

[0025] In one or more embodiments, the superhydrophobic-lubricating composite coating comprises, from bottom to top, a superhydrophobic coating and a lubricating coating.

[0026] Preferably, the superhydrophobic coating material is nano-silica.

[0027] Preferably, the lubricating coating material is fluorinated oil or silicone oil;

[0028] The fluorinated oil includes FC40 fluorinated liquid; the silicone oil includes polydimethylsiloxane (PDMS).

[0029] A second typical embodiment of the present invention provides a method for preparing the bubble separation device described in the first aspect, comprising the following steps:

[0030] The design grooves are etched into the base plate. After washing and drying, a superhydrophobic coating is applied to the surface of the base plate between adjacent grooves. After drying, the entire base plate is immersed in lubricating fluid and dried again to form the bubble separation device.

[0031] In one or more embodiments, the contact angle of the superhydrophobic coating is greater than 150°.

[0032] A third typical embodiment of the present invention provides a system for producing hydrogen by electrolysis of water, including the bubble separation device described in the first aspect.

[0033] Preferably, the water electrolysis hydrogen production system includes an electrochemical workstation and an electrolyzer. The electrolyzer contains an auxiliary electrode, a reference electrode, and a working electrode component. The working electrode component includes a working electrode and a bubble separation device. The working electrode is connected to one end of the bubble separation device where a bubble separation channel is arranged.

[0034] More preferably, the auxiliary electrode, reference electrode, and working electrode components are all connected to the electrochemical workstation via wires.

[0035] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0036] Example 1

[0037] Figure 1 This is a schematic diagram of a bubble separation device, for reference. Figure 1 A bubble separation device includes a base plate 1, one end of which is provided with a plurality of interconnected through grooves 2, the through grooves 2 extending in a divergent manner toward the other end of the base plate 1; bubble separation channels 3 are formed between adjacent through grooves 2, and a superhydrophobic-lubricating composite coating is provided on the surface of the base plate 1 where the bubble separation channels 3 are located.

[0038] The base plate 1 is made of polymethyl methacrylate (PMMA), which is easy to process.

[0039] The included angle between adjacent channels 2 is 2° to 8°. The included angle between adjacent channels 2 is the included angle of the bubble separation channel 3. A smaller included angle can achieve a faster transport speed and a longer transport distance for the bubbles.

[0040] The width of the through groove 2 is 0.5 to 2 mm. The limitation of the width of the through groove 2 can balance the ratio of bubble growth size to carrier size, providing sufficient space for bubble growth while controlling the size of the carrier.

[0041] The superhydrophobic-lubricating composite coating comprises a superhydrophobic coating and a lubricating coating from bottom to top. The superhydrophobic coating material is nano-silica; the lubricating coating material is fluorinated oil or silicone oil, where the fluorinated oil is FC40 fluorinated liquid; and the silicone oil is polydimethylsiloxane (PDMS).

[0042] Example 2

[0043] A polymethyl methacrylate (PMMA) sheet measuring 30 mm in length, 22 mm in width, and 1 mm in thickness was placed in a CO2 laser etching apparatus. Through-grooves were formed by etching the PMMA sheet under the conditions set in Example 1, with the laser power set to 25 W and the scanning speed to 100 mm / s. By controlling the laser power and scanning speed, the uniformity and precision of the microstructure were ensured to achieve optimal bubble guiding effect. After etching, the PMMA sheet was ultrasonically cleaned with a mixture of deionized water and anhydrous ethanol (volume ratio 1:1) for 5 minutes each time, repeated twice, to remove surface processing residues and particulate impurities.

[0044] After cleaning, the polymethyl methacrylate (PMMA) sheet was dried in a clean environment at 50°C for 30 minutes to ensure complete surface drying. Aerosil R202 fumed silica was then uniformly coated onto the dried PMMA sheet surface to form a uniform hydrophobic coating. After coating, the surface was allowed to cure naturally at room temperature for 12 hours, and the contact angle was tested to reach over 150°. Figure 3 (As shown), its superhydrophobic properties were verified. The hydrophobically modified polymethyl methacrylate sheet was immersed in fluorinated oil lubricant for 3 minutes to ensure complete coverage of the surface lubricant layer. After lubrication treatment, the polymethyl methacrylate sheet was removed and placed in a dust-free environment to air dry, thus obtaining the bubble separation device.

[0045] Example 3

[0046] The bubble separation device prepared in Example 2 was applied to a system for producing hydrogen by water electrolysis. Figure 2 In the electrolysis of water to produce hydrogen system, there are an electrochemical workstation 4 and an electrolyzer 5. The electrolyzer 5 contains an auxiliary electrode 6, a reference electrode 7 and a working electrode component. The working electrode component includes a working electrode 10 and a bubble separation device 8. The working electrode 10 and one end of the bubble separation device 8 with a bubble separation channel are connected by a platinum electrode clamp. The auxiliary electrode 6, the reference electrode 7 and the working electrode component are all connected to the electrochemical workstation 4 by wires 11.

[0047] A 5 g / L KOH solution was used as the electrolyte. The open-circuit voltage was set to 1.5 V. The experiment was conducted under constant voltage power supply for 5 minutes. The generation, movement, desorption, and collection of bubbles were observed. A schematic diagram of the bubble movement process is shown below. Figure 4 As shown, from Figure 4 As can be seen, bubble 1 moves towards the root of the triangle under asymmetric Laplace pressure and stabilizes at the position of maximum contact area; bubble 2 continues this process and merges with bubble 1; after merging, the bubble grows and continues to slide towards the root of the triangle under asymmetric Laplace pressure, eventually detaching when the buoyancy exceeds the adhesion force. The experimental results show that the bubbles exhibit obvious directional migration characteristics on the surface of the geometric gradient circumferential array, rapidly moving from near the electrode to the array tip where they are captured and successfully directionally migrated, completing the migration in just a few milliseconds. After the experiment, the electrolysis current was measured to be 0.006 A (6 mA) lower than that of the conventional device, and the energy consumption was reduced by about 18%.

[0048] Example 4

[0049] This embodiment uses the same water electrolysis hydrogen production system as Embodiment 3.

[0050] A 5 g / L KOH solution was used as the electrolyte, and the open-circuit voltage was set to 2 V. The experiment was conducted under constant voltage power supply for 5 minutes, observing the generation, movement, desorption, and collection of bubbles. The results showed that the bubbles exhibited significant directional migration characteristics on the surface of the geometric gradient circular array. They rapidly moved from near the electrodes to the array tip, where they were captured and successfully directionally migrated, completing the migration within milliseconds. After the experiment, the electrolysis current was measured to be 0.008 A (8 mA) lower than that of the conventional device, and energy consumption was reduced by approximately 12.5%.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the 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 bubble separation device, characterized in that, Includes a base plate, one end of which is provided with a plurality of interconnected through grooves, which extend in a divergent manner toward the other end of the base plate; bubble separation channels are formed between adjacent through grooves, and a superhydrophobic-lubricating composite coating is provided on the surface of the base plate where the bubble separation channels are located; The superhydrophobic-lubricating composite coating includes, from bottom to top, a superhydrophobic coating and a lubricating coating; The included angle between adjacent through slots is 2° to 8°.

2. The bubble separation device as described in claim 1, characterized in that, The base plate is made of polymethyl methacrylate.

3. The bubble separation device as described in claim 1, characterized in that, The width of the through groove is 0.5~2 mm.

4. The bubble separation device as described in claim 1, characterized in that, The superhydrophobic coating material is nano-silica; Alternatively, the lubricating coating material may be fluorinated oil or silicone oil.

5. The method for preparing the bubble separation device according to any one of claims 1 to 4, characterized in that, Includes the following steps: The design grooves are etched into the base plate. After washing and drying, a superhydrophobic coating is applied to the surface of the base plate between adjacent grooves. After drying, the entire base plate is immersed in lubricating fluid and dried again to form the bubble separation device.

6. The preparation method according to claim 5, characterized in that, The contact angle of the superhydrophobic coating is greater than 150°.

7. A system for producing hydrogen by electrolysis of water, characterized in that, Includes the bubble separation device according to any one of claims 1 to 4.

8. The system as described in claim 7, characterized in that, The system for producing hydrogen by water electrolysis includes an electrochemical workstation and an electrolyzer. The electrolyzer contains an auxiliary electrode, a reference electrode, and a working electrode component. The working electrode component includes a working electrode and a bubble separation device. The working electrode is connected to one end of the bubble separation device where a bubble separation channel is arranged.

9. The system as described in claim 8, characterized in that, The auxiliary electrode, reference electrode, and working electrode components are all connected to the electrochemical workstation via wires.

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