In-situ visualization of microelectrode electrocatalytic bubble dynamics and methods of use

Abstract

The application discloses a visual microelectrode in-situ electrocatalysis bubble dynamics observation device and a use method thereof. The device comprises a transparent electrolytic cell, a bottom support and an electrode system. The electrode system comprises a reference electrode, a counter electrode and a microelectrode assembly. The top of the transparent electrolytic cell is inserted into the reference electrode and the counter electrode. The microelectrode assembly is inserted from the bottom of the transparent electrolytic cell and comprises a microelectrode and a threaded connector. A through guide hole is arranged in the threaded connector, and the microelectrode is arranged in the through guide hole. The included angle between the center line of the through guide hole and the axis of the threaded connector is 0-60 degrees. The observation device realizes multi-angle liquid-tight sealing and angle locking of the microelectrode at the bottom of the transparent electrolytic cell through the microelectrode assembly with an adjustable inclination angle, and facilitates in-situ observation of bubble dynamics behavior at different inclination angles. The device has compact structure and high assembly repeatability, can provide a clear observation window without damaging the system sealing, and provides a platform for electrolytic interface phenomenon research.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical experimental devices and in-situ visualization observation technology, specifically relating to a visualization microelectrode in-situ electrocatalytic bubble dynamics observation device and its usage method. Background Technology

[0002] Electrocatalytic gas evolution reactions play a crucial role in energy conversion and storage. During gas evolution, the nucleation, growth, coverage, and desorption of bubbles on the electrode surface alter interfacial wetting and local mass transfer conditions, leading to a reduction in the effective reaction area and the introduction of additional ohmic drop and mass transfer resistance, thereby increasing the reaction overpotential and energy consumption.

[0003] Existing experimental electrolyzers are mostly sealed, large-volume systems, making it difficult to directly observe the behavior of products at the electrode / electrolyte interface from the outside, which easily creates a "black box" reaction environment. At the same time, on large-sized electrodes, the location of bubble formation and the desorption process are random and disordered, making it difficult to conduct in-situ, quantitative, and reproducible studies on the kinetic parameters of individual bubbles.

[0004] Existing apparatuses typically only allow for the study of vertical or horizontal electrodes. However, in actual industrial electrolyzers, electrodes are often installed at an angle to improve mass transfer efficiency. There is a lack of a precision platform that allows for continuous angle adjustment and comparative studies of the "angle-gas evolution rate" relationship within the same apparatus.

[0005] Microelectrodes have well-defined geometric shapes and characteristic mass transfer behaviors, and the controllable generation of single or small numbers of bubbles can be achieved on their end faces, facilitating systematic research on bubble nucleation, growth, detachment, and accompanying potential / current fluctuations.

[0006] Therefore, a compact, reliably sealed, and easily observable multi-angle visual electrolytic cell structure is needed. Summary of the Invention

[0007] To address the aforementioned problems in the prior art, this invention provides a visualization microelectrode in-situ electrocatalytic bubble dynamics observation device and its usage method. This observation device, through an adjustable tilt angle microelectrode assembly, achieves multi-angle liquid-tight sealing and angle locking of the microelectrode at the bottom of a transparent electrolyzer, facilitating in-situ observation of bubble dynamics behavior at different tilt angles.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a visual microelectrode in-situ bubble dynamics observation device, the device comprising a transparent electrolytic cell, a bottom support and an electrode system, the electrode system comprising a reference electrode, a counter electrode and a microelectrode assembly;

[0010] The top of the transparent electrolytic cell is provided with at least two through holes for inserting the reference electrode and the counter electrode;

[0011] The microelectrode assembly includes a microelectrode and a threaded connector. The threaded connector has a through guide hole inside, and the microelectrode passes through the through guide hole. The angle between the center line of the through guide hole and the axis of the threaded connector is an inclination angle, and the value of the inclination angle is 0~60°.

[0012] The bottom of the transparent electrolytic cell is provided with a first through threaded hole;

[0013] The bottom bracket is used to support the transparent electrolytic cell, and the bottom bracket is provided with a second through threaded hole at a position corresponding to the first through threaded hole.

[0014] The threaded connector is inserted and fixed inside the first through threaded hole and the second through threaded hole.

[0015] In some embodiments, the through guide hole is a gradually expanding hole, and the ratio of its lower end diameter to its upper end diameter is 1:(1.05-1.15).

[0016] In some embodiments, an inverted conical sealing sleeve is attached inside the through guide hole. The inside of the inverted conical sealing sleeve is a tapered hole, and the ratio of the lower end diameter to the upper end diameter is 1:(0.90-0.95).

[0017] In some embodiments, the inverted conical sealing sleeve is made of polytetrafluoroethylene or perfluoroether rubber.

[0018] In some embodiments, the threaded connector is stepped, comprising an upper small-diameter section and a lower large-diameter section;

[0019] The first through threaded hole is adapted to the minor diameter section of the threaded connector;

[0020] The second through threaded hole is adapted to the major diameter section of the threaded connector.

[0021] In some embodiments, the microelectrode assembly further includes two O-rings, which are fitted over the upper and lower portions of the microelectrode and abut against the upper and lower ends of the threaded connector to achieve a seal.

[0022] In some embodiments, the microelectrode includes an electrode core, an insulating encapsulation layer sleeved on the outside of the electrode core, and an electrical connection structure fixedly connected to one side of the electrode core.

[0023] The electrode core material is platinum, gold, silver, or glassy carbon;

[0024] The diameter of the micro-electrode end facet is 2~2000 μm.

[0025] In some embodiments, the bottom support includes a limiting groove and a bracket fixedly connected to the limiting groove;

[0026] The size of the limiting groove matches the size of the transparent electrolytic cell to prevent shaking.

[0027] In some embodiments, the transparent electrolytic cell is made of quartz glass or borosilicate glass; the wall thickness of the transparent electrolytic cell is 10-15 mm to meet the requirements of light transmittance and structural strength for in-situ visualization observation.

[0028] Secondly, the present invention provides a method for using the above-mentioned visualization microelectrode in-situ bubble dynamics observation device, comprising the following steps:

[0029] S1: Select a threaded connector with a corresponding tilt angle for the through guide hole, based on the tilt angle required for the experiment.

[0030] S2: Place the transparent electrolytic cell on the bottom support so that the first through threaded hole and the second through threaded hole are coaxially aligned;

[0031] S3: Insert the threaded connector into the first through threaded hole and the second through threaded hole from bottom to top, tighten and fix it to realize the assembly of the transparent electrolytic cell and the bottom support.

[0032] S4: Insert and fix the microelectrode into the through guide hole to complete the assembly of the microelectrode assembly;

[0033] S5: Add electrolyte into the transparent electrolytic cell, and then insert the reference electrode and the counter electrode;

[0034] S6: Start the electrolysis reaction and conduct in-situ visualization observation of bubble dynamics.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] (1) The observation device of the present invention uses a series of replaceable threaded connectors, which can realize in-situ observation of electrode interface phenomena under different gravity components.

[0037] (2) The observation device of the present invention adopts an inverted conical sealing sleeve and an O-ring to form a multi-layer liquid-tight seal, and is equipped with a detachable bottom bracket to ensure reliable sealing and repeated disassembly and assembly of the microelectrode, and to meet the needs of bottom electrode installation and adaptation to electrolytic cells of different heights.

[0038] (3) The transparent electrolytic cell combined with the micro electrode end face design in this invention can directly observe the single bubble behavior at the electrode / electrolyte interface in situ, breaking through the traditional "black box" reaction environment and providing an intuitive and repeatable experimental platform for the quantitative study of bubble dynamics parameters. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of a visualization microelectrode in-situ bubble dynamics observation device.

[0040] Figure 2 This is a top view of a transparent electrolytic cell.

[0041] Figure 3 This is a schematic diagram of the microelectrode assembly (tilt angle is 0°).

[0042] Figure 4 This is a structural schematic diagram of a threaded connection.

[0043] Figure 5 It is a longitudinal sectional view of a transparent electrolytic cell.

[0044] Figure 6 This is a longitudinal sectional view of the bottom support.

[0045] Figure 7 This is a schematic diagram of an observation system based on a visual microelectrode in-situ bubble dynamics observation device.

[0046] Figure 8 It is a diagram of the bubble growth process taken at 125fps.

[0047] Figure 9 It is a picture of the bubble growth process taken at 1000fps.

[0048] In the picture:

[0049] 10-Transparent electrolytic cell; 11-Through hole; 12-First through threaded hole;

[0050] 20-Bottom bracket; 21-Second through threaded hole; 22-Limiting groove; 23-Bracket;

[0051] 30-Microelectrode assembly; 31-Microelectrode; 32-Threaded connector; 33-Through guide hole; 34-Small diameter section; 35-Large diameter section; 36-Inverted conical sealing sleeve; 37-O-ring seal;

[0052] 40 - Reference electrode; 50 - Counter electrode; 60 - Electrochemical workstation; 70 - Computer; 80 - High-speed camera; 90 - Light source. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0054] Example 1: A visual microelectrode in-situ bubble dynamics observation device:

[0055] refer to Figure 1 This embodiment provides a visualization microelectrode in-situ bubble dynamics observation device. The device includes a transparent electrolytic cell 10, a bottom support 20, and an electrode system. The electrode system includes a microelectrode assembly 30, a reference electrode 40, and a counter electrode 50.

[0056] Combination Figure 2 As shown, the top of the transparent electrolytic cell 10 is provided with at least two through holes 11, preferably with a diameter of 2 mm, for inserting the reference electrode 40 and the counter electrode 50. The reference electrode 40 and the counter electrode 50 are provided with adaptable rubber O-rings or elastic sealing rings at the through holes 11 to achieve radial positioning of the electrodes, limitation of insertion depth, and liquid sealing. The remaining through holes 11 serve as venting holes.

[0057] Combination Figure 3 and Figure 4 As shown, the microelectrode assembly 30 includes a microelectrode 31 and a threaded connector 32. The threaded connector 32 has a through guide hole 33 inside, and the microelectrode 31 passes through the through guide hole 33. The threaded connector 32 is stepped, including an upper small diameter section 34 and a lower large diameter section 35.

[0058] The angle between the centerline of the through guide hole 33 and the axis of the threaded connector 32 is an inclination angle. The inclination angle ranges from 0 to 60°. Different inclination angles can be set according to actual needs to achieve multi-angle observation.

[0059] The through guide hole 33 is a gradually expanding hole, and the ratio of its lower end diameter to its upper end diameter is 1:(1.05-1.15).

[0060] An inverted conical sealing sleeve 36 is fitted inside the through guide hole 33. The interior of the inverted conical sealing sleeve 36 is a tapered hole, with the ratio of its lower end diameter to its upper end diameter being 1:(0.90-0.95). The inverted conical sealing sleeve 36 is made of polytetrafluoroethylene or perfluoroether rubber. When the microelectrode 31 is inserted into the through guide hole 33, it compresses the inverted conical sealing sleeve 36, causing it to deform radially, thereby simultaneously locking the tilt angle of the microelectrode 31 and achieving a liquid-tight seal on the electrode sidewall.

[0061] like Figure 5 and Figure 6 As shown, the bottom of the transparent electrolytic cell 10 is provided with a first through threaded hole 12; the first through threaded hole 12 is adapted to the small diameter section 34 of the threaded connector 32;

[0062] The bottom bracket 20 is used to support the transparent electrolytic cell 10. The bottom bracket 20 is provided with a second through threaded hole 21 at a position corresponding to the first through threaded hole 12. The second through threaded hole 21 is adapted to the large diameter section 35 of the threaded connector 32.

[0063] The threaded connector 32 is inserted and fixed inside the first through threaded hole 12 and the second through threaded hole 21.

[0064] The microelectrode assembly 30 also includes two O-rings 37, which are fitted onto the upper and lower parts of the microelectrode 31 and abut against the upper and lower ends of the threaded connector 32 to achieve a seal.

[0065] Furthermore, the microelectrode 31 is a working electrode, including an internal electrode core and an external insulating encapsulation layer, as well as an electrical connection structure fixedly connected to one side of the electrode core; the end face of the microelectrode 31 is preferably a disc-shaped end face with a diameter of 2 μm to 2000 μm.

[0066] The electrode core material is platinum, gold, silver, glassy carbon, or other commonly used corrosion-resistant conductive materials in the art; the insulating encapsulation layer is used to limit the effective reaction area and prevent gas evolution on the sidewalls, and its material can be glass, epoxy resin, polyimide, or polytetrafluoroethylene.

[0067] Furthermore, the bottom support 20 includes a limiting groove 22 and a bracket 23 fixedly connected to the limiting groove 22; the size of the limiting groove 22 matches the size of the transparent electrolytic cell 10 to prevent wobbling. The bottom support 20 is detachably assembled with the transparent electrolytic cell 10 via a threaded connector 32, which can accommodate transparent electrolytic cells 10 of different heights. The bottom support 20 can be made of metal or engineering plastic, and must have sufficient rigidity and corrosion resistance.

[0068] Furthermore, the thread specification of the first through-hole 12 at the bottom of the transparent electrolytic cell 10 is between M4 and M8, preferably M4, and can be adjusted according to the outer diameter and installation space of the microelectrode assembly 30.

[0069] The thread specification of the second through threaded hole 21 of the bottom bracket 20 is between M8 and M16, preferably M8, so as to cooperate with the large diameter section 35 of the threaded connector 32 and achieve locking.

[0070] Furthermore, the wall thickness of the transparent electrolytic cell 10 is 10-15 mm to meet the requirements of light transmittance and structural strength for in-situ visualization observation. The bottom length of the transparent electrolytic cell 10 is 40 mm-60 mm, the bottom width is 40 mm-60 mm, the inner cavity length is 30 mm-50 mm, the inner cavity width is 30 mm-50 mm, the height is 60 mm-80 mm, and the bottom thickness is 10 mm-15 mm.

[0071] More preferably, the transparent electrolytic cell 10 has external dimensions of 40 mm × 40 mm × 60 mm, internal cavity dimensions of 30 mm × 30 mm × 50 mm, and a bottom thickness of 10 mm.

[0072] Furthermore, the transparent electrolytic cell 10 includes an open electrolytic cell body and a top cover for sealing its top;

[0073] The transparent electrolytic cell 10 is made of quartz glass, borosilicate glass, or other transparent corrosion-resistant materials commonly used in the art; the top cover is preferably made of corrosion-resistant insulating material, such as polytetrafluoroethylene.

[0074] Example 2: A method for using a visual microelectrode in-situ bubble dynamics observation device:

[0075] This embodiment provides a method for using the visualization microelectrode in-situ bubble dynamics observation device of Embodiment 1 described above, including the following steps:

[0076] S1: Select a threaded connector 32 with a corresponding tilt angle from the through guide hole 33 according to the angle required for the experiment;

[0077] S2: Place the transparent electrolytic cell 10 on the bottom support 20 so that the first through threaded hole 12 and the second through threaded hole 21 are coaxially aligned.

[0078] S3: Insert the threaded connector 32 into the first through threaded hole 12 and the second through threaded hole 21 from bottom to top, and tighten it to fix it, so as to realize the assembly of the transparent electrolytic cell 10 and the bottom support 20.

[0079] S4: Insert and fix the microelectrode 31 into the through guide hole 33, thus completing the assembly of the microelectrode assembly 30;

[0080] S5: Add electrolyte into the transparent electrolytic cell 10, and then insert the reference electrode 40 and the counter electrode 50;

[0081] S6: Start the electrolysis reaction and conduct in-situ visualization observation of bubble dynamics.

[0082] Application examples

[0083] This application example is based on the visualization microelectrode in-situ bubble dynamics observation device of Embodiment 1 described above, and is constructed as follows: Figure 7 The observation system shown comprises an electrochemical workstation 60, a computer 70, and a high-speed camera 80 connected sequentially. The high-speed camera 80 and the light source 90 are located on the left and right sides of the transparent electrolytic cell 10, respectively. The optical axis of the lens of the high-speed camera 80 is parallel to the end face of the microelectrode 31. A hydrogen evolution reaction is performed on the 100 μm diameter microelectrode 31 under a constant current of -0.1 mA. The tilt angle within the threaded connector 32 is 15°. The reference electrode 40 uses a mercurous sulfate electrode, and the counter electrode 50 uses a 500 μm diameter platinum wire electrode. The electrolyte is 0.5 M sulfuric acid. The electrochemical workstation records the voltage change over time, and the high-speed camera 80 records the entire process of bubble growth and desorption on the electrode surface.

[0084] Under the conditions of an electrolysis time of 100s and a frame rate of 125fps for a high-speed camera, the growth and desorption process of 30 bubbles were recorded. Figure 8 and Figure 9 The entire growth and desorption process of a bubble on a microelectrode 31 with a diameter of 100 μm is demonstrated. Analysis of the captured images shows that the average diameter of the bubble is approximately 970 μm, and the average time for a single bubble to grow from the electrode surface to desorption is approximately 1.8 s.

[0085] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A visualization microelectrode in-situ bubble dynamics observation device, characterized in that, The device includes a transparent electrolytic cell, a bottom support, and an electrode system, wherein the electrode system includes a reference electrode, a counter electrode, and a microelectrode assembly. The top of the transparent electrolytic cell is provided with at least two through holes for inserting the reference electrode and the counter electrode; The microelectrode assembly includes a microelectrode and a threaded connector. The threaded connector has a through guide hole inside, and the microelectrode passes through the through guide hole. The angle between the center line of the through guide hole and the axis of the threaded connector is an inclination angle, and the value of the inclination angle is 0~60°. The bottom of the transparent electrolytic cell is provided with a first through threaded hole; The bottom bracket is used to support the transparent electrolytic cell, and the bottom bracket is provided with a second through threaded hole at a position corresponding to the first through threaded hole. The threaded connector is inserted and fixed inside the first through threaded hole and the second through threaded hole. The through guide hole is a gradually expanding hole, and the ratio of its lower end diameter to its upper end diameter is 1:(1.05-1.15); an inverted conical sealing sleeve is attached inside the through guide hole, and the inside of the inverted conical sealing sleeve is a gradually narrowing hole, and the ratio of its lower end diameter to its upper end diameter is 1:(0.90-0.95).

2. The in-situ bubble dynamics observation device with visualization microelectrode according to claim 1, characterized in that, The inverted conical sealing sleeve is made of polytetrafluoroethylene or perfluoroether rubber.

3. The in-situ bubble dynamics observation device with visualization microelectrode according to claim 1, characterized in that, The threaded connector is stepped, consisting of a small-diameter section at the top and a large-diameter section at the bottom; The first through threaded hole is adapted to the minor diameter section of the threaded connector; The second through threaded hole is adapted to the major diameter section of the threaded connector.

4. The in-situ bubble dynamics observation device with visualization microelectrode according to claim 1 or 2, characterized in that, The microelectrode assembly also includes two O-rings, which are fitted over the upper and lower parts of the microelectrode and abut against the upper and lower ends of the threaded connector to achieve a seal.

5. The in-situ bubble dynamics observation device with visualization microelectrode according to claim 1, characterized in that, The microelectrode includes an electrode core, an insulating encapsulation layer sleeved on the outside of the electrode core, and an electrical connection structure fixedly connected to one side of the electrode core. The electrode core material is platinum, gold, silver, or glassy carbon; The diameter of the micro-electrode end facet is 2~2000 μm.

6. The in-situ bubble dynamics observation device with visualization microelectrode according to claim 1, characterized in that, The bottom support includes a limiting groove and a bracket fixedly connected to the limiting groove; The size of the limiting groove matches the size of the transparent electrolytic cell to prevent shaking.

7. The in-situ bubble dynamics observation device with visualization microelectrode according to claim 1, characterized in that, The transparent electrolytic cell is made of quartz glass or borosilicate glass; the wall thickness of the transparent electrolytic cell is 10~15mm.

8. The method of using the visual microelectrode in-situ bubble dynamics observation device as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1: Select a threaded connector with a corresponding tilt angle for the through guide hole, based on the tilt angle required for the experiment. S2: Place the transparent electrolytic cell on the bottom support so that the first through threaded hole and the second through threaded hole are coaxially aligned; S3: Insert the threaded connector into the first through threaded hole and the second through threaded hole from bottom to top, tighten and fix it to realize the assembly of the transparent electrolytic cell and the bottom support. S4: Insert and fix the microelectrode into the through guide hole to complete the assembly of the microelectrode assembly; S5: Add electrolyte into the transparent electrolytic cell, and then insert the reference electrode and the counter electrode; S6: Start the electrolysis reaction and conduct in-situ visualization observation of bubble dynamics.

Images