Luggin capillary gas diffusion electrolytic tank and method thereof

Abstract

The invention relates to the technical field of electrochemistry, and discloses a Luggin capillary gas diffusion electrolytic cell and a method thereof.The Luggin capillary gas diffusion electrolytic cell comprises a working electrode, a Luggin capillary, a Nafion tube, a reference electrode, a counter electrode and electrolyte, and further comprises a thermometer and an exhaust channel; the outer wall of the Luggin capillary tube is fixedly connected to the bottom side of the gas diffusion electrolytic cell, the Nafion tube is arranged in an opening, close to the end of the working electrode, of the Luggin capillary tube in a penetrating manner, the working electrode, the reference electrode and the counter electrode are all arranged in the electrolyte, and the counter electrode and the working electrode are oppositely arranged in the electrolytic cell body. The Luggin capillary tube is fixedly arranged on the bottom side of the gas diffusion electrolytic tank, so that the solution resistance reducing effect of the Luggin capillary tube is exerted, the uniform distribution of electric field lines between the working electrode and the counter electrode is not influenced, the uniformity of an electric field between the working electrode and the counter electrode is ensured, and the electrochemical test precision is improved.

Description

Technical Field

[0001] The invention relates to the technical field of electrochemistry, in particular to a Luggin capillary gas diffusion electrolytic cell and a method thereof. Background Art

[0002] In today's era of rapid technological development, electrochemical technology plays a vital role in many fields and is widely used in new energy development, material corrosion research, etc. In these application scenarios, the gas diffusion electrolytic cell is a key electrochemical test device for testing various planar electrode materials. Its performance directly affects the accuracy and reliability of the test results, and thus has an important impact on the research and industrial development of related fields.

[0003] The gas diffusion electrolytic cell is a commonly used electrochemical testing device. It can be used for electrochemical testing of gas diffusion electrodes and membrane electrodes, and can also be used for electrochemical testing of corrosion of plates and coatings. It is widely used in new energy, corrosion testing and other fields. In the electrochemical testing process of the gas diffusion electrolytic cell, accurately measuring the potential of the working electrode is the key link to obtain accurate test results.

[0004] When using a traditional Luggin capillary, it needs to be inserted into the gas diffusion electrolytic cell as an additional component. Since the depth and angle of each insertion are difficult to accurately control, large variations will occur. This position uncertainty makes the distance and relative position between the reference electrode and the working electrode different in each test. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a Luggin capillary gas diffusion electrolytic cell and method thereof, which solves the problem that when using the traditional Luggin capillary, the change in solution resistance is difficult to accurately measure, thereby affecting the accuracy of the test data.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a Luggin capillary gas diffusion electrolytic cell, comprising a working electrode, a Luggin capillary, a Nafion tube, a reference electrode, a counter electrode and an electrolyte, the gas diffusion electrolytic cell also comprising a thermometer and an exhaust channel, the outer wall of the Luggin capillary is fixedly connected to the bottom side of the gas diffusion electrolytic cell, one end of the working electrode is provided with an opening, the Nafion tube is inserted into the opening of the Luggin capillary close to the working electrode end, electric field lines are provided inside the electrode, the working electrode, the reference electrode and the counter electrode are all arranged inside the electrolyte, and the counter electrode and the working electrode are relatively arranged in the electrolytic cell body.

[0007] Preferably, the number of openings of the working electrode is between 2 and 10.

[0008] Preferably, the reference electrode is electrically connected to the electrolyte near the working electrode through a Luggin capillary and a Nafion tube.

[0009] Preferably, the outer wall of the thermometer is fixedly connected to the inner wall of the electrolytic cell body, and the detection end is immersed in the electrolyte.

[0010] Preferably, the outer diameter of the Nafion tube is between 0.3 mm and 1.3 mm, which is compatible with the opening of the Luggin capillary.

[0011] Preferably, an exhaust passage is provided on the top of the electrolytic cell body, and the exhaust passage is connected to the interior of the electrolytic cell body.

[0012] Preferably, the working electrode, reference electrode and counter electrode are all connected to an external electrochemical testing device via wires.

[0013] Preferably, the opening diameter of each capillary of the working electrode is 0.5 mm-1.5 mm.

[0014] Preferably, a sealing gasket is provided between the reference electrode and the counter electrode.

[0015] Preferably, a method for using a Luggin capillary gas diffusion electrolytic cell comprises the following steps: S1. Preparation: Use tweezers to place the nickel felt electrode at the working electrode position, add electrolyte to the electrolytic cell, and completely immerse the working electrode, reference electrode and counter electrode in the electrolyte; S2, electrode insertion, inserting the reference electrode, the reference electrode adopts a reversible hydrogen RHE reference electrode, and the reversible hydrogen RHE reference electrode is electrically connected to the electrolyte near the working electrode through a Luggin capillary and a Nafion tube; S3, test connection and setting, connect the electrochemical test device, the electrochemical test device uses an electrochemical workstation, and set the electrochemical test program and parameters according to the test requirements; S4. Start the test and monitor the temperature of the electrolyte in real time through a thermometer. At the same time, use the exhaust channel to promptly discharge the gas generated during the electrolysis process.

[0016] The present invention provides a Luggin capillary gas diffusion electrolytic cell and a method thereof, which have the following beneficial effects: 1. The present invention fixes a Luggin capillary on the bottom side of the gas diffusion electrolytic cell and opens it very close to the working electrode. This not only makes the Luggin capillary play a role in reducing the solution resistance, but also does not affect the uniform distribution of the electric field lines between the working electrode and the counter electrode, thereby ensuring the uniformity of the electric field between the working electrode and the counter electrode, and improving the accuracy of electrochemical testing. More accurate data can be obtained when testing the Luggin capillary opening number CV by cyclic voltammetry and the Luggin capillary opening number LSV by linear scanning test.

[0017] 2. The present invention fixes the Luggin capillary on the bottom side of the gas diffusion electrolytic cell so that the position of the Luggin capillary is fixed and repeated each time the test is performed, thereby avoiding the test differences caused by changes in the insertion depth and angle of the traditional Luggin capillary, simplifying the reference electrode installation process, and thus increasing the reproducibility of the electrochemical test.

[0018] 3. The present invention increases the number of Luggin capillary openings and Nafion Luggin capillary openings in the Luggin capillary cavity, and solves the problem of the traditional Luggin capillary being complicated to assemble and prone to residual bubbles causing circuit breakage by taking advantage of the particularity of proton conductivity. During the test, ion conduction can be stably achieved, ensuring the electrical connection between the reference electrode and the working electrode, and ensuring the smooth progress of the test.

[0019] 4. The number of openings of the working electrode of the present invention is between 2 and 10. Multiple openings allow the electrolyte to flow to the surface of the working electrode from different positions, providing sufficient reactants for the electrochemical reaction, promoting the redox reaction, ensuring the sufficiency and stability of the electrochemical reaction during the test, reducing the probability of a single opening being blocked, and further improving the reliability of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 2 is a flow chart of the method of using the present invention; Figure 3 It is a cyclic voltammetry test CV diagram of the present invention; Figure 4 It is the linear scan test LSV diagram of the present invention; Figure 5 This is a comparison diagram of the test with and without the Luggin capillary of the present invention; Figure 6 This is a schematic diagram for comparing the reproducibility of three tests of the present invention.

[0021] Among them, 1. working electrode; 2. number of openings at the electrode end; 3. Nafion tube; 4. Luggin capillary; 5. electrochemical test device; 6. reference electrode; 7. thermometer; 8. electric field lines; 9. exhaust channel; 10. counter electrode; 11. electrolyte. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Please refer to the attached Figure 1 An embodiment of the present invention provides a Luggin capillary gas diffusion electrolytic cell, comprising a working electrode 1, a Luggin capillary 4, a Nafion tube 3, a reference electrode 6, a counter electrode 10 and an electrolyte 11. The gas diffusion electrolytic cell further comprises a thermometer 7 and an exhaust channel 9. The outer wall of the Luggin capillary 4 is fixedly connected to the bottom side of the gas diffusion electrolytic cell. An opening is provided at one end of the working electrode 1. The Nafion tube 3 is inserted into the opening of the Luggin capillary 4 near the end of the working electrode 1. An electric field line 8 is provided inside the electrode 10. The working electrode 1, the reference electrode 6 and the counter electrode 10 are all arranged inside the electrolyte 11. The counter electrode 10 and the working electrode 1 are arranged relatively in the electrolytic cell body.

[0024] Specifically, the outer wall of the Luggin capillary 4 is fixed on the bottom side of the gas diffusion electrolytic cell, with an opening near the working electrode 1 end. By means of capillary phenomenon, the electrolyte 11 flows through the opening to the interface between the working electrode 1 and the reference electrode 6, effectively reducing the solution resistance and the potential error caused by the solution resistance, without affecting the uniform distribution of the electric field lines 8 between the working electrode 1 and the counter electrode 10, ensuring the uniformity of the electric field, thereby improving the accuracy of electrochemical testing. The number of openings 2 at the electrode end is the number of openings of the Luggin capillary 4 near the working electrode 1 end, and the Nafion tube 3 is inserted into the opening of the Luggin capillary 4 near the working electrode 1 end, which solves the problem of complex assembly of the traditional Luggin capillary 4 and easy residual bubbles causing circuit breakage.

[0025] Please refer to the attached Figure 1 The number of openings of the working electrode 1 is between 2 and 10; the reference electrode 6 is electrically connected to the electrolyte 11 near the working electrode 1 through the Luggin capillary 4 and the Nafion tube 3; the outer wall of the thermometer 7 is fixedly connected to the inner wall of the electrolytic cell body, and the detection end is immersed in the electrolyte 11.

[0026] Specifically, the number of openings of the working electrode 1 is between 2 and 10. Multiple openings allow the electrolyte 11 to flow to the surface of the working electrode from different positions, providing sufficient reactants for the electrochemical reaction, promoting the redox reaction, and ensuring the sufficiency and stability of the electrochemical reaction during the test, thereby improving the reliability of the test results. If the number of openings is too small, once a single opening is blocked by impurities, it may seriously affect the circulation of the electrolyte 11, thereby interfering with the electrochemical reaction and the test results. The Luggin capillary 4 uses the capillary phenomenon to allow the electrolyte 11 to flow inside it, effectively reducing the solution resistance and reducing the potential measurement error caused by the solution resistance. The Nafion tube 3 uses its own proton conductivity to ensure ion conduction while avoiding the problem of complex assembly of the traditional Luggin capillary 4 and easy residual bubbles causing circuit breakage, further ensuring the stability of the electrical connection between the reference electrode 6 and the working electrode 1, thereby achieving accurate measurement of the working electrode potential and improving the accuracy of electrochemical testing.

[0027] Please refer to the attached Figure 1 The outer diameter of the Nafion tube 3 is between 0.3 mm and 1.3 mm, which is adapted to the opening of the Luggin capillary 4; an exhaust channel 9 is provided on the top of the electrolytic cell body, and the exhaust channel 9 is connected to the inside of the electrolytic cell body.

[0028] Specifically, the outer diameter of the Nafion tube 3 is between 0.3 mm and 1.3 mm and is adapted to the opening of the Luggin capillary 4. This size design ensures that the Nafion tube 3 fits tightly in the opening of the Luggin capillary 4, prevents leakage of the electrolyte 11, maintains the stability of the ion conduction path, and ensures that protons are smoothly conducted through the Nafion tube 3, thereby providing a stable ion transmission environment for the electrochemical reaction between the working electrode 1 and the reference electrode 6, ensuring the accuracy of the potential measurement during the test and the reliability of the electrochemical test results. During the electrolysis process, redox reactions will occur on the surfaces of the working electrode 1 and the counter electrode 10 to generate gases such as hydrogen and oxygen. The exhaust channel 9 on the top of the electrolytic cell body is connected to the interior, and can discharge these generated gases out of the electrolytic cell in time.

[0029] Please refer to the attached Figure 1 The working electrode 1, the reference electrode 6, and the counter electrode 10 are all connected to the external electrochemical testing device 5 through wires; the opening diameter of each capillary of the working electrode 1 is 0.5mm-1.5mm; a sealing gasket is provided between the reference electrode 6 and the counter electrode 10.

[0030] Specifically, the working electrode 1, the reference electrode 6, and the counter electrode 10 are all connected to the external electrochemical testing device 5 through wires to construct a complete electrochemical testing circuit. The external electrochemical testing device 5, such as an electrochemical workstation, can apply a specific potential or current signal to the working electrode 1 to induce an electrochemical reaction. The electrochemical reaction signal generated on the working electrode 1 is transmitted to the testing device 5 through the wire for collection and analysis. A sealing gasket is arranged between the reference electrode 6 and the counter electrode 10 to prevent leakage of the electrolyte and to avoid loss of the electrolyte 11 resulting in instability of the testing system.

[0031] Please refer to the attached Figure 2 , a method for using a Luggin capillary gas diffusion electrolytic cell, comprising the following steps: S1. Preparation: Use tweezers to place the nickel felt electrode at the position of the working electrode 1, add electrolyte 11 to the electrolytic cell, and the electrolyte 11 completely immerses the working electrode 1, the reference electrode 6 and the counter electrode 10; S2, electrode insertion, inserting the reference electrode 6, the reference electrode 6 adopts a reversible hydrogen RHE reference electrode, and the reversible hydrogen RHE reference electrode is electrically connected to the electrolyte 11 near the working electrode 1 through the Luggin capillary 4 and the Nafion tube 3; S3, test connection and setting, connecting the electrochemical test device 5, the electrochemical test device 5 adopts an electrochemical workstation, and setting the electrochemical test program and parameters according to the test requirements; S4, start the test, monitor the temperature of the electrolyte 11 in real time through the thermometer 7, and at the same time, use the exhaust channel 9 to discharge the gas generated during the electrolysis process in time.

[0032] Specifically, first, the nickel felt electrode to be tested is placed at the position of the working electrode 1, an appropriate amount of electrolyte 11 is added to the electrolytic cell, and a reference electrode 6, such as a reversible hydrogen RHE reference electrode, is inserted, and then an electrochemical testing device 5, such as an electrochemical workstation, is connected, and the electrochemical testing program and parameters are set. The Luggin capillary 4 is fixed on the bottom side of the gas diffusion electrolytic cell, and the number of openings close to the working electrode 1 end is between 2-10, and the diameter of the openings is between 0.5mm-1.5mm. The Luggin capillary 4 can use the capillary phenomenon to allow the electrolyte 11 to flow through the openings to the interface between the working electrode 1 and the reference electrode 6, thereby playing a role in reducing the resistance of the solution, and will not affect the uniform distribution of the electric field lines 8 between the working electrode 1 and the counter electrode 10. A Nafion tube 3 with an outer diameter of between 0.3mm-1.3mm is inserted into the opening of the Luggin capillary 4. The proton conductive properties of Nafion are utilized to ensure ion conduction while solving the problem of complex assembly of the traditional Luggin capillary 4 and easy residual bubbles causing circuit breakage. During the entire test process, the thermometer 7 monitors the temperature of the electrolyte 11 in real time, and the exhaust channel 9 is used to discharge the gas generated during the electrolysis process to ensure a stable test environment. Through the above structure and operation, the Luggin capillary 4 gas diffusion electrolytic cell can not only perform various electrochemical tests like conventional gas diffusion electrolytic cells, such as cyclic voltammetry test CV and linear sweep test LSV, but also reduce the solution resistance between the reference electrode 6 and the working electrode 1, and improve the reproducibility of multiple tests.

[0033] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A Luggin capillary gas diffusion electrolytic cell, characterized in that: The gas diffusion electrolytic cell comprises a working electrode (1), a Luggin capillary (4), a Nafion tube (3), a reference electrode (6), a counter electrode (10) and an electrolyte (11). The gas diffusion electrolytic cell further comprises a thermometer (7) and an exhaust channel (9). The outer wall of the Luggin capillary (4) is fixedly connected to the bottom side of the gas diffusion electrolytic cell. An opening is provided at one end of the working electrode (1). The Nafion tube (3) is inserted into the opening of the Luggin capillary (4) near the end of the working electrode (1). An electric field line (8) is provided inside the electrode (10). The working electrode (1), the reference electrode (6) and the counter electrode (10) are all arranged inside the electrolyte (11). The counter electrode (10) and the working electrode (1) are arranged relative to each other in the electrolytic cell body.

2. A Luggin capillary gas diffusion electrolytic cell according to claim 1, characterized in that: The number of openings of the working electrode (1) is between 2 and 10.

3. A Luggin capillary gas diffusion electrolytic cell according to claim 1, characterized in that: The reference electrode (6) is electrically connected to the electrolyte (11) near the working electrode (1) via a Luggin capillary (4) and a Nafion tube (3).

4. A Luggin capillary gas diffusion electrolytic cell according to claim 1, characterized in that: The outer wall of the thermometer (7) is fixedly connected to the inner wall of the electrolytic cell body, and the detection end is immersed in the electrolyte (11).

5. A Luggin capillary gas diffusion electrolytic cell according to claim 1, characterized in that: The outer diameter of the Nafion tube (3) is between 0.3 mm and 1.3 mm, and is adapted to the opening of the Luggin capillary (4).

6. A Luggin capillary gas diffusion electrolytic cell according to claim 1, characterized in that: An exhaust channel (9) is provided on the top of the electrolytic cell body, and the exhaust channel (9) is connected to the inside of the electrolytic cell body.

7. A Luggin capillary gas diffusion electrolytic cell according to claim 1, characterized in that: The working electrode (1), the reference electrode (6), and the counter electrode (10) are all connected to an external electrochemical testing device (5) via wires.

8. The Luggin capillary gas diffusion electrolytic cell according to claim 1, characterized in that: The opening diameter of each capillary of the working electrode (1) is 0.5 mm to 1.5 mm.

9. A Luggin capillary gas diffusion electrolytic cell according to claim 1, characterized in that: A sealing gasket is provided between the reference electrode (6) and the counter electrode (10).

10. A method for using a Luggin capillary gas diffusion electrolytic cell, characterized in that: The Luggin capillary gas diffusion electrolytic cell applied to any one of claims 1 to 6 comprises the following steps: S1. Preparation: Use tweezers to place the nickel felt electrode at the position of the working electrode (1), add electrolyte (11) to the electrolytic cell, and the electrolyte (11) completely immerses the working electrode (1), the reference electrode (6) and the counter electrode (10); S2, electrode insertion, inserting a reference electrode (6), wherein the reference electrode (6) is a reversible hydrogen RHE reference electrode, and the reversible hydrogen RHE reference electrode is electrically connected to the electrolyte (11) near the working electrode (1) through a Luggin capillary (4) and a Nafion tube (3); S3, test connection and setting, connecting the electrochemical test device (5), the electrochemical test device (5) adopts an electrochemical workstation, and setting the electrochemical test program and parameters according to the test requirements; S4, start the test, monitor the temperature of the electrolyte (11) in real time through the thermometer (7), and at the same time, use the exhaust channel (9) to timely discharge the gas generated during the electrolysis process.

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