Dual-electrode structure capable of stably, continuously and independently generating double bubbles and preparation method

Abstract

The invention provides a dual-electrode structure capable of stably, continuously and independently generating double bubbles and a preparation method. The dual-electrode structure comprises an external insulating tube, an electrode wire, an internal insulating tube, a wire and a sealing body, a first electrode wire is arranged in the internal insulating tube, a second electrode wire is arranged in the external insulating tube, the first electrode wire is parallel to the second electrode wire, the first ends of the first electrode wire and the second electrode wire are connected with a wire, and the second ends of the first electrode wire and the second electrode wire are flush with and sealed with the end face of the external insulating tube. A sealing body is arranged in a gap among the external insulating tube, the wire and the internal insulating tube at the first end; the first end of the internal insulating tube and the first end of the first electrode wire are arranged in the sealing body, and the two electrode wires are insulated in the external insulating tube; and micron-sized single bubbles are generated on the surface of the electrode, so that short circuit or corrosion caused by electrolyte leakage is prevented, generation of multiple bubbles on the surface of the electrode is eradicated fundamentally, it is guaranteed that the electrode only generates single bubbles at the same time, and the service life of the device is prolonged.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogen production by water electrolysis, and particularly relates to a double-electrode structure capable of stably and continuously generating double bubbles and a preparation method. BACKGROUND

[0002] Hydrogen energy, as a clean and low-carbon energy carrier, has the characteristics of long-time energy storage, can solve the problem of insufficient renewable energy consumption capacity and new energy grid connection, and can improve the flexibility of the power grid and realize efficient use of energy by using the electricity of "stranded light" and "stranded wind" to produce hydrogen through water electrolysis. It is an important source of "green hydrogen". The gas generated in the process of water electrolysis usually gathers into bubbles in the solution and escapes, which reduces the coverage of the electrode surface, reduces the electrocatalytic active sites, and increases the ohmic resistance in the electrolysis process, thereby greatly affecting the efficiency of water electrolysis. Therefore, studying bubble dynamics, understanding and controlling bubble movement, and promoting bubble detachment are one of the key problems in water electrolysis systems.

[0003] At present, the research on bubble dynamics mainly focuses on two types of electrode systems: one is a micro-single electrode system, which generates a single bubble on the surface of a micron-sized electrode to study the dynamics of the entire cycle of bubble nucleation, growth and detachment; the other is a large-area electrode system, which generates a large number of bubbles on the surface of a centimeter-sized electrode to study the coalescence and interaction rules between multiple bubbles.

[0004] However, the existing research systems still have the following key challenges in studying the bubble dynamics mechanism: (1) Limitations of micro-single electrode: In the micro-single electrode system, the observed bubble dynamics mainly reflects the growth characteristics and movement state of a single bubble during water electrolysis, and cannot reflect the interaction and interference effects between multiple bubbles in the actual electrolysis system. Therefore, there is a deviation between single-bubble dynamics and actual multi-bubble dynamics.

[0005] (2) Limitations of large-area electrode: In the large-area electrode system, the random nucleation and uneven growth of bubbles lead to the rapid generation of a large number of bubbles of different sizes at the same time, making it difficult to achieve controlled generation of bubbles of a specific size; the interaction between bubbles leads to group characteristics in their movement behavior; the surface of the bubbles generated by the large-area electrode fluctuates violently, and the stability of the bubbles is poor. These factors make the experimental process of studying the coalescence behavior of multiple bubbles complex and time-consuming.

[0006] (3) Limitations of traditional double-electrode structure: To study the interaction between bubbles, some studies have attempted to arrange two micro-single electrodes side by side to generate and coalesce double bubbles. However, ensuring that the surfaces of the two micro-single electrodes are located on the same horizontal plane and reasonably controlling the distance between the two electrodes makes it difficult to operate and has a low success rate.

[0007] In summary, the existing bubble dynamics research system has deficiencies in controllability of double-bubble generation and repeatability of bubble coalescence process, and a micro double-electrode structure with high controllability is urgently needed to realize accurate regulation of the whole process of bubble nucleation, growth, coalescence and detachment. SUMMARY

[0008] To address the above challenges, the present application provides a double-electrode structure capable of stably and continuously generating double bubbles independently, which can independently control the bubble size generated by the two electrodes, realize the repeated generation of two bubbles with any radius and radius ratio, and simultaneously study the dynamics of single bubble and the coalescence dynamics between multiple bubbles.

[0009] To achieve the above purpose, in a first aspect, the present application provides a double-electrode structure capable of stably and continuously generating double bubbles independently, comprising an external insulating tube, an electrode wire, an internal insulating tube, a lead wire and a sealing body; the internal insulating tube is arranged in the external insulating tube, the internal insulating tube has a first electrode wire, the external insulating tube has a second electrode wire, the first electrode wire and the second electrode wire are parallel, the first ends of the first electrode wire and the second electrode wire are connected to the lead wire, the second ends of the first electrode wire and the second electrode wire are flush with the end face of the external insulating tube and are sealed, and the gap between the external insulating tube, the lead wire and the internal insulating tube at the first end is provided with the sealing body; the first end of the internal insulating tube and the first end of the first electrode wire are arranged in the sealing body, the second end of the internal insulating tube is suspended, and the two electrode wires are insulated in the external insulating tube.

[0010] Further, the internal insulating tube is a capillary tube, and the diameter of the second electrode wire is greater than the diameter of the first electrode wire.

[0011] Further, the lead wire is a lead wire with an insulating layer.

[0012] Further, the material of the external insulating tube is soda-lime glass, the material of the internal insulating tube is glass, and the sealing body is made of silicone.

[0013] Further, the internal space of the external insulating tube is filled with insulating material.

[0014] Further, the first electrode wire and the second electrode wire are respectively connected to the output end of a programmable power supply.

[0015] In a second aspect, the present application can provide a water electrolysis hydrogen production device using the above-mentioned double-electrode structure capable of stably and continuously generating double bubbles independently.

[0016] In a third aspect, the present application provides a preparation method of the above-mentioned double-electrode structure capable of stably and continuously generating double bubbles independently, comprising the following steps: Take the first electrode line, the second electrode line and the lead, connect the first electrode line, the second electrode line with the lead respectively, the first electrode line is inserted into the internal insulation pipe, the first electrode line and the second electrode line are inserted into the external insulation pipe side by side; Seal the second end of the external insulation pipe, the second end of the first electrode line and the second electrode line passes through the end face of the second end of the external insulation pipe;The first end of the external insulation pipe is sealed with a sealing body; After polishing the second end of the first electrode line and the second electrode line and the second end of the external insulation pipe, ultrasonic cleaning in deionized water, the second end of the first electrode line and the second electrode line is put into the electrolytic cell for electrochemical cleaning, and the double electrode structure capable of stably and continuously generating double bubbles is obtained.

[0017] Further, when polishing the second end of the first electrode line and the second electrode line, the electrode surface is polished flat using a polisher, and then the electrode surface is polished by rotating 3000 mesh sandpaper.

[0018] Further, the electrochemical cleaning is carried out in 1M H2SO4 for several times of 0.03-1.35V vs.RHE redox reaction cycles.

[0019] Compared with the prior art, the beneficial effects of the present application are: The present application provides a double electrode structure capable of stably and continuously generating double bubbles, which adopts a micro single electrode design of inserting a metal wire into an insulation pipe, combines a composite process of top fusion sealing and bottom silica gel packaging of a glass pipe, constructs an electrode structure with high air tightness and high insulation, applies voltage to the micro single electrode and places it into an electrolyte, which can generate micron-level single bubbles on the electrode surface, prevents short circuit or corrosion caused by electrolyte leakage, eliminates the generation of multiple bubbles on the electrode surface from the root, ensures that the electrode generates only single bubbles at the same time, and prolongs the service life of the device. On the basis of the single electrode structure, a platinum wire electrode with a capillary tube is further inserted to form a double electrode structure. Different voltages are independently applied to the two electrodes and placed into an electrolyte, which can independently generate micron-level bubble pairs of different radii on the surfaces of the two electrodes. The inserted capillary tube effectively avoids the short circuit of the two electrodes due to contact.

[0020] The present application provides a double electrode structure capable of stably and continuously generating double bubbles, which can flexibly generate bubbles from micron level to millimeter level by selecting metal wires with different diameters and materials. By adjusting the wall thickness of the capillary tube, the distance between the electrodes can be accurately controlled from millimeter level to micron level, thereby realizing accurate control of bubble radius at the time of coalescence.

[0021] Further, by applying programmable voltage / current signals (such as direct current, pulse, step waveform) to the two electrodes respectively and independently, and adjusting the amplitude, frequency, duty cycle and other parameters of the signals, the growth rate and radius of individual bubbles can be accurately and independently controlled, thereby stably and repeatedly generating bubbles with specific radius and radius ratio. The parameter set can be pre-set as a standardized program to ensure experimental reproducibility, providing a reliable and repeatable means for studying bubble coalescence dynamics.

[0022] Further, the inner insulation tube uses a capillary tube to fix and protect the thinner first electrode wire, preventing it from bending, vibrating or contacting the second electrode wire. The size difference between the two electrodes helps optimize current distribution and mechanical stability, facilitating independent bubble generation.

[0023] Further, the outer insulation tube uses sodium-calcium glass, and the inner insulation tube uses a capillary glass tube to provide chemical inertness, insulation and mechanical strength, allowing long-term stability in an electrolyte environment. Silicone is used as a sealing body, which has good elasticity, sealing performance and chemical corrosion resistance, effectively adapting to thermal expansion and contraction while maintaining long-term sealing.

[0024] Further, filling the inner part of the outer insulation tube with insulation material can further enhance the insulation strength between the two electrode wires, fix the internal structure to reduce vibration or movement, and possibly improve the overall mechanical strength and pressure resistance, making the structure more robust and reliable.

[0025] Further, programmable power supply allows independent application or accurate control of different potentials / currents to the two electrodes, which can be used to study bubble generation dynamics, optimize gas production efficiency, or achieve specific reaction modes, making the structure not only a component but also a flexible experimental or production platform.

[0026] Further, by integrating it into an electrolytic water device, it can improve the efficiency, bubble release characteristics and possible operational stability of the entire hydrogen production device, and can develop from an experimental structure to a practical device.

[0027] Further, after fine polishing, the electrode working end surface is extremely flat, smooth and clean. The flat end surface is the physical basis for uniform nucleation and growth of bubbles, and the smooth surface can reduce unnecessary bubble adhesion, making the generated bubbles easier to detach, achieving continuous gas production, and reducing local current density unevenness caused by surface roughness.

[0028] Further, cyclic voltammetry scanning in dilute sulfuric acid helps completely remove oxides or organic contaminants formed on the electrode surface during polishing and in air; it can form a stable and highly active surface state on the metal electrode surface; and it ensures that the electrode has excellent catalytic activity and stability from the first use. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 A schematic diagram of a double electrode structure for stably and continuously generating double bubbles independently according to the present application; Figure 2 A cross-sectional schematic diagram of a double electrode structure for stably and continuously generating double bubbles independently according to the present application; Figure 3 Pictures of bubble coalescence in an embodiment of the present application, with double electrode voltages of (a) -1V, -1V; (b) -2V, -1V; (c) -3V, -1V; (d) -4V, -1V; Figure 4 Current curves in an electrolysis process in an embodiment of the present application, with double electrode voltages of (a) -1V, -1V; (b) -2V, -1V.

[0030] In the drawings, 1 is a sodium-calcium glass tube, 2 is a platinum wire, 3 is a capillary glass tube, 4 is a copper wire, and 5 is silica gel. DETAILED DESCRIPTION

[0031] The present application provides a physical diagram and a cross-sectional schematic diagram of a double electrode structure for stably and continuously generating double bubbles independently, which comprises an external insulation tube, an electrode wire, an internal insulation tube, a wire, and a sealing body; the internal insulation tube is arranged in the external insulation tube, the internal insulation tube has a first electrode wire, the external insulation tube is provided with a second electrode wire, the first electrode wire and the second electrode wire are parallel, the first ends of the first electrode wire and the second electrode wire are connected to the wire, the second ends of the first electrode wire and the second electrode wire are flush with the end face of the external insulation tube and are sealed, and the gap between the external insulation tube, the wire, and the internal insulation tube at the first end is provided with the sealing body; the first end of the internal insulation tube and the first end of the first electrode wire are both arranged in the sealing body, the second end of the internal insulation tube is suspended, and the two electrode wires are insulated in the external insulation tube; the present application establishes a coaxial, parallel, and mutually insulated double electrode, the external insulation tube provides main support and sealing; the internal insulation tube ensures that the two electrode wires are absolutely insulated even in the space of the external insulation tube, preventing short circuit; the electrode end face is flush and sealed, the working end face is neat, and bubbles are generated at the same physical starting point; and the sealing body prevents the electrolyte from seeping from the end of the wire to cause short circuit or corrosion, thereby providing a reliable mechanical and electrical framework for stable, continuous, and independent gas production.

[0032] The present application provides a preparation method of a double electrode structure for stably and continuously generating double bubbles independently, which comprises the following steps: The first electrode wire, the second electrode wire, and the wire are taken, the first electrode wire and the second electrode wire are respectively connected to the wire, the first electrode wire is inserted into the internal insulation tube, and the first electrode wire and the second electrode wire are inserted into the external insulation tube side by side; Sealing the second end of the outer insulation tube, the second end of the first electrode wire and the second electrode wire pass through the end face of the second end of the outer insulation tube; sealing the first end of the outer insulation tube with a sealing body; After polishing the second end of the first electrode wire and the second electrode wire and the second end of the outer insulation tube, ultrasonic cleaning in deionized water, the second end of the first electrode wire and the second electrode wire are put into an electrolytic cell for electrochemical cleaning, and a double-electrode structure capable of stably and continuously generating double bubbles is obtained.

[0033] The inner insulation tube and the outer insulation tube can also be plastic tubes.

[0034] To make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art without creative labor based on the embodiments in the present application belong to the scope of protection of the present application.

[0035] Various structural schematic diagrams according to the disclosed embodiments of the present application are shown in the drawings. These diagrams are not drawn to scale, in which certain details are exaggerated for the purpose of clarity and certain details can be omitted. The shapes of various regions, layers and their relative size and positional relationship shown in the diagrams are only exemplary, and in actuality, there can be deviations due to manufacturing tolerances or technical limitations, and regions / layers with different shapes, sizes and relative positions can be additionally designed by those skilled in the art according to actual needs.

[0036] Embodiments, with reference to Figure 1 and Figure 2 As shown, the inner insulation tube is a capillary glass tube 3, and the wire is a copper wire with an insulation layer; the outer insulation tube is a soda-lime glass tube; and the sealing body is silicone. A physical diagram and a cross-sectional schematic diagram of a double-electrode structure capable of stably and continuously generating double bubbles include a soda-lime glass tube 1, a platinum wire 2, a capillary glass tube 3, a copper wire 4 and silicone 5, and the platinum wire 2 functions to generate micro-bubbles by electrolyzing water.

[0037] The platinum wire 2 is inserted into the soda-lime glass tube 1, and after being burned and fused at the top of the soda-lime glass tube 1 with an alcohol lamp, it is polished horizontally to prevent liquid leakage. The copper wire 4 is connected with the platinum wire to serve as an external circuit for transmitting current. A section of the copper wire 4 is cut off, and a small part of the outer insulation rubber is peeled off, and the exposed copper wire is connected with the platinum wire 1, and the remaining copper wire is connected with the external circuit. Through the design of the unique double-electrode structure, the independent control of the two bubbles is realized, and the problem that the prior art can only generate a single bubble or is difficult to control multiple bubbles is overcome, thereby providing a reliable experimental platform for studying the interaction between bubbles; the design of the double-electrode structure enables each electrode to work independently, thereby not only improving the stability of bubble generation, but also accurately controlling the size and radius ratio of the bubble on a microscale, solving the problems of random nucleation and uneven growth of bubbles in a large-area electrode system; through optimization of the electrode material and structure, the fluctuation of the bubble surface is reduced, the stability of the bubble is improved, the continuous and stable generation of the bubble in the electrochemical process is ensured, and the behavior characteristics of the bubble on the electrode surface are conducive to in-depth research. The preparation method is simple and reliable, easy to operate, overcomes the problems of large operation difficulty and low success rate of the double-micro single-electrode structure in the prior art, the entire assembly process does not require complex tools or high-precision operation skills, greatly simplifies the experimental preparation process, reduces the experimental cost, and improves the success rate of the experiment, and is suitable for laboratory research and future possible industrial production needs.

[0038] The surface is subjected to micro-treatment to reduce the fluctuation of the bubble surface, solve the problems of random nucleation and uneven growth of bubbles caused by uneven current distribution in a traditional large-area electrode, ensure the continuous and stable formation of the bubble on the electrode surface, and provide ideal experimental conditions for studying the dynamic behavior of the bubble.

[0039] The capillary glass tube 3 is a key component of the double electrode, which is used to separate the platinum wires 2 in the soda-lime glass tube 1, so that the platinum wires 2 are not in contact and can conduct electricity independently to achieve the purpose of independent control. The outer diameter of the capillary glass tube 3 is much smaller than that of the soda-lime glass tube 1, and the inner diameter is slightly larger than that of the platinum wire 2, and by changing the outer diameter of the capillary glass tube 3, the spacing of the two electrodes can be controlled. When the capillary glass tube 3 is inserted, it is ensured that the top of the capillary glass tube 3 is not in contact with the top of the soda-lime glass tube 1, otherwise there will be liquid leakage after burning and polishing, or the properties of the two electrodes will be different, mainly manifested as the two electrodes generating bubbles of different radii under the same voltage. The copper wire connected with the platinum wire without the capillary glass tube 3 overlaps with the capillary glass tube outside the other platinum wire to ensure that there is no contact between the two platinum wires. The bottom of the soda-lime glass tube 1 is sealed with silica gel 5 to ensure that the electrolyte does not enter the glass tube, and to block the exposed copper wire, thereby improving the safety of the device during operation.

[0040] The working process of the device is as follows: the copper wire 4 is connected with the working electrode of the electrochemical workstation. When a single bubble is needed, one wire is selected and connected with the working electrode; when double bubbles are needed, two wires are needed to be connected with two working electrodes respectively, and different voltages are applied to generate bubble pairs with different radii and radius ratios.

[0041] For the first electrode wire proposed in the present application, a platinum wire electrode with a diameter of 100 μm is used, and platinum wires with different radii or metal wires made of other materials can also be used as electrodes.

[0042] As an optional embodiment, both electrode wires are made of metal materials with good conductivity and corrosion resistance, such as platinum, gold or iridium, to ensure long-term stable bubble generation effect.

[0043] In order to further improve the generation efficiency and stability of the bubbles, a nanoscale catalyst layer is deposited on the surface of the electrode to reduce the overpotential required for bubble formation and reduce energy consumption. It also helps to reduce the contact angle between the bubble and the electrode surface, making the bubble easier to detach from the electrode surface, reducing the adhesion phenomenon between the bubbles, and improving the flowability and uniformity of the bubbles.

[0044] Experimental conditions: for the double electrode preparation, a sodium-calcium glass tube with an outer diameter of 2.3 mm and an inner diameter of 2.0 mm, a capillary glass tube with an outer diameter of 0.3 mm and an inner diameter of 0.2 mm, a 100 μm platinum wire electrode, and an electrode spacing of 200 μm are used. The working electrode is a double electrode, the counter electrode is a 500 μm platinum electrode, the reference electrode is an Ag / AgCl electrode, the electrolyte is 0.5 M H2SO4, and the cathode voltage range of the double electrode is -1 V to -4 V.

[0045] The present application will be further described in combination with the drawings: Figure 3 The image is for the coalescence process of bubble pairs with different radii generated by applying different voltages to the double electrodes. When the same voltage is applied to both ends of the double electrode, a pair of bubbles with the same radius will be generated, and the bubble radius ratio is 1. Changing the voltage at one end of the double electrode will change the corresponding bubble radius ratio during bubble coalescence.

[0046] Figure 4 The current curve is for the use of double electrode electrolysis. When the same voltage is applied to both ends of the double electrode, the current of the two electrodes is approximately equal; changing the voltage of the double electrode will also change the current. The periodic change of the current curve reflects the periodic detachment of the bubbles generated by the double electrode from the electrode surface.

[0047] The above content only illustrates the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made on the basis of the technical solution according to the technical idea of the present application falls within the protection scope of the claims of the present application.

Claims

1. A dual-electrode structure capable of stably, continuously, and independently generating two bubbles, characterized in that, It includes an outer insulating tube, electrode wires, an inner insulating tube, a conductor, and a sealing body. The inner insulating tube is set inside the outer insulating tube, and a first electrode wire is located in the inner insulating tube. A second electrode wire is located in the outer insulating tube. The first and second electrode wires are parallel. The first ends of the first and second electrode wires are connected to the conductor. The second ends of the first and second electrode wires are flush with and sealed to the end face of the outer insulating tube. A sealing body is set in the gap between the outer insulating tube, the conductor, and the inner insulating tube at the first end. The first end of the inner insulating tube and the first end of the first electrode wire are both placed in the sealing body. The second end of the inner insulating tube is suspended. The two electrode wires are insulated inside the outer insulating tube.

2. The dual-electrode structure capable of stably, continuously, and independently generating two bubbles according to claim 1, characterized in that, The internal insulating tube is a capillary tube, and the diameter of the second electrode wire is larger than the diameter of the first electrode wire.

3. The dual-electrode structure capable of stably, continuously, and independently generating two bubbles according to claim 1, characterized in that, The conductor is an insulated conductor.

4. The dual-electrode structure capable of stably, continuously, and independently generating dual bubbles according to claim 1, characterized in that, The outer insulating tube is made of soda-lime glass, the inner insulating tube is made of glass, and the sealing body is made of silicone.

5. The dual-electrode structure capable of stably, continuously, and independently generating two bubbles according to claim 1, characterized in that, The internal space of the external insulating tube is filled with insulating material.

6. The dual-electrode structure capable of stably, continuously, and independently generating two bubbles according to claim 1, characterized in that, The first electrode line and the second electrode line are respectively connected to the programmable power output terminal.

7. A device for producing hydrogen by electrolysis of water, characterized in that, The dual-electrode structure described in any one of claims 1-6 is capable of stably, continuously and independently generating two bubbles.

8. The method for preparing a dual-electrode structure capable of stably, continuously, and independently generating dual bubbles as described in any one of claims 1-6, characterized in that, Includes the following steps: Take the first electrode wire, the second electrode wire, and the wire. Connect the first electrode wire and the second electrode wire to the wire respectively. Insert the first electrode wire into the inner insulating tube. Insert the first electrode wire and the second electrode wire side by side into the outer insulating tube. Seal the second end of the external insulating tube, and pass the second ends of the first and second electrode wires through the end face of the second end of the external insulating tube; seal the first end of the external insulating tube with a sealing body; After grinding the second ends of the first electrode wire and the second electrode wire, as well as the second end of the external insulating tube, flatten them, ultrasonically clean them in deionized water, and then place the second ends of the first electrode wire and the second electrode wire into an electrolytic cell for electrochemical cleaning, thus obtaining a dual-electrode structure that can stably, continuously and independently generate double bubbles.

9. The method for preparing a dual-electrode structure capable of stably, continuously, and independently generating dual bubbles according to claim 8, characterized in that, When polishing the second end of the first and second electrode wires, use a polisher to smooth the electrode surface, and then use 3000-grit sandpaper to polish the electrode surface in a circular motion.

10. The method for preparing a dual-electrode structure capable of stably and continuously generating dual bubbles independently according to claim 8, characterized in that, Electrochemical cleaning was performed in 1M H2SO4 with several cycles of redox reactions at 0.03-1.35V vs. RHE.

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