A reference electrode with ultrathin ion channel

Abstract

The application discloses a reference electrode with an ultrathin ion channel, which comprises an insulating tube, an inner reference electrode, a conductor and an ultrathin ion channel, the insulating tube is filled with electrolyte, the inner reference electrode and the conductor are arranged in the insulating tube and are led out from two ends of the insulating tube respectively, an insulating sealing material is arranged at one end of the insulating tube where the inner reference electrode is led out, a through hole is arranged at the other end of the insulating tube, the conductor is led out from the through hole, a gap with a size less than 50 nm is left between the outer surface of the conductor and the peripheral wall of the through hole, the electrolyte in the insulating tube is communicated with external electrolyte through the gap, and the ultrathin ion channel is formed. The electrode potential of the reference electrode is the electrode potential of the inner reference electrode, compared with the commonly used commercial reference electrode, the reference electrode has the advantages of high stability, extremely small electrolyte leakage, small interference on electrochemical test, simple storage condition and controllable size.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical and analytical chemistry research technology, and specifically relates to a reference electrode with an ultrathin ion channel. Background Technology

[0002] Since the absolute potential of an electrode cannot be measured, a reference value is designated for the potential of one electrode, which is then used to determine the relative potentials of other electrodes. Internationally (IUPAC), the potential of the standard hydrogen electrode is defined as zero, and the relative potentials of various electrodes obtained by comparing them against this reference are called electrode potentials.

[0003] Standard hydrogen electrode setups and experimental procedures are quite cumbersome, and they are generally only used as primary standards. In practical applications, a type of slightly soluble salt electrode, such as the calomel electrode, silver-silver chloride electrode, and mercury-mercurous sulfate electrode, is commonly used as a secondary standard. These electrodes are often called reference electrodes. During use, the internal solution, such as potassium chloride or sulfate solution, must flow out slowly to ensure conductivity of the reference electrode.

[0004] Reference electrodes have been widely used in various electrochemical and electroanalytical fields, but some obvious problems remain unresolved. First, commonly used laboratory saturated calomel or silver-silver chloride electrodes exhibit rapid leakage of potassium chloride solution during use, significantly contaminating the studied system. To overcome this problem, existing solutions typically replace porous ceramic plugs with slow-leaking materials such as nanoporous glass plugs or mesoporous polymer plugs, but this introduces the disadvantage of complex fabrication. In particular, these nanoporous materials result in reference electrode resistances on the order of MΩ, leading to severe noise interference and increasing the RC constant, thus reducing the response speed of the electrochemical system. Second, the commonly used laboratory saturated calomel or silver-silver chloride reference electrodes often have large sizes due to the need for porous ceramic plugs at the electrode ends. This makes them unsuitable for electrochemical studies requiring tiny reference electrodes, such as electrochemical scanning tunneling microscopy, scanning electrochemical cell microscopy, nanopores, and brain electrodes. Therefore, these studies can only use potentially unstable metal quasi-reference electrodes. Developing potential-stable micro-reference electrodes to replace potential-unstable metal quasi-reference electrodes is of great significance for the aforementioned special electrochemical research. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a reference electrode with an ultrathin ion channel, which solves the problems of pollution caused by rapid internal solution loss and large electrode size in the above-mentioned background art.

[0006] The technical solution adopted by this invention to solve its technical problem is as follows: a reference electrode with an ultrathin ion channel is provided, characterized in that it includes an insulating tube, an internal reference electrode, a conductor, and an ultrathin ion channel. The insulating tube is filled with an electrolyte. The internal reference electrode and the conductor are disposed inside the insulating tube and led out from both ends of the insulating tube, respectively. An insulating sealing material is provided at one end of the insulating tube from which the internal reference electrode is led out, and a through hole is provided at the other end. The conductor is led out from the through hole. A gap with a size of less than 50 nm is left between the outer surface of the conductor and the peripheral wall of the through hole. The electrolyte inside the insulating tube is connected to the external electrolyte through the gap to form an ultrathin ion channel.

[0007] In this invention, the two end faces of the conductor are in contact with the electrolyte inside the insulating tube and the external electrolyte, respectively.

[0008] In this invention, the insulating tube is made of materials including glass, quartz, ceramic, and polymer materials.

[0009] In this invention, the insulating and sealing materials include epoxy resin plugs, sealing films, silicone plugs, and heat-sealing tubes.

[0010] In this invention, the internal reference electrode includes a silver-silver chloride electrode, a calomel electrode, a mercury-mercurous sulfate electrode, and a mercury-mercurous oxide electrode.

[0011] In this invention, the electrolyte includes potassium chloride solution, sodium chloride solution, potassium sulfate solution, sodium sulfate solution, sulfuric acid solution, sodium hydroxide solution, and potassium hydroxide solution.

[0012] In this invention, the conductor includes platinum, gold, silver, copper, palladium, rhodium, iridium, and alloy materials, as well as glassy carbon, carbon rods, carbon fibers, and conductive glass.

[0013] The reference electrode potential of this technical solution is the same as that of its built-in reference electrode, and it has the same potential response as commercially available reference electrodes used in daily life. Compared with the prior art, it has the following advantages:

[0014] 1. This method uses a conductor instead of the porous ceramic plug in a conventional reference electrode, making the preparation process extremely simple.

[0015] 2. This solution allows the size of the reference electrode to be adjusted to suit various application scenarios by changing the dimensions of the insulating tube, internal reference electrode, and conductor. Compared to commercial reference electrodes, miniaturization can be achieved very easily.

[0016] 3. The ultrathin ion channel between the conductor and the insulating tube in this scheme greatly reduces the leakage rate of ions inside the reference electrode, significantly reducing contamination of the electrochemical system. Its internal resistance is comparable to that of a traditional reference electrode, making it suitable for research on almost all electrochemical systems, including micro-volume electrochemical technology.

[0017] 4. Compared to the harsh conditions that ordinary reference electrodes need to be stored in electrolyte, the reference electrode involved in this solution can be placed directly in the atmospheric environment without solution protection. The storage conditions are simple, and the potential can be kept accurate and stable for a long time. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of Example 1.

[0019] Figure 2 This is a graph showing the electrode potential stability test results of Example 1.

[0020] Figure 3 This is a comparison diagram of the electrodes used in Example 1 and Comparative Example 1 for electrochemical testing. Detailed Implementation

[0021] Example 1

[0022] This embodiment discloses a reference electrode with an ultrathin ion channel, comprising an insulating tube, an internal reference electrode, a conductor, and an ultrathin ion channel. The insulating tube is filled with an electrolyte. The internal reference electrode and the conductor are disposed within the insulating tube and led out from both ends of the insulating tube, respectively. An insulating sealing material is provided at one end of the insulating tube from which the internal reference electrode is led out, and a through hole is provided at the other end. The conductor is led out through the through hole, and a gap of less than 50 nm is left between the outer surface of the conductor and the peripheral wall of the through hole. In this embodiment, the internal reference electrode is a silver-silver chloride electrode, and the electrolyte in the insulating tube is a potassium chloride solution. An external electrolyte is provided outside the insulating tube. The two end faces of the conductor are in contact with the electrolyte inside the insulating tube and the external electrolyte, respectively. The electrolyte inside the insulating tube communicates with the external electrolyte through the gap, forming an ultrathin ion channel.

[0023] Comparative Example 1

[0024] Comparative Example 1 is a standard silver-silver chloride reference electrode.

[0025] Comparing Example 1 with Comparative Example 1: From Figure 2 As can be seen, the electrode potential difference between Example 1 and Comparative Example 1 is essentially zero, and the electrode potential exhibits excellent stability. Figure 3 As can be seen, the reference electrodes of Example 1 and Comparative Example 1 have the same electrochemical response.

[0026] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A reference electrode with an ultrathin ion channel, characterized in that: The device includes an insulating tube, an internal reference electrode, and a conductor. The insulating tube is filled with an electrolyte. The internal reference electrode and the conductor are disposed inside the insulating tube and led out from both ends of the insulating tube. An insulating sealing material is provided at one end of the insulating tube from which the internal reference electrode is led out, and a through hole is provided at the other end. The conductor is led out from the through hole. A gap with a size of less than 50 nm is left between the outer surface of the conductor and the peripheral wall of the through hole. The electrolyte inside the insulating tube is connected to the external electrolyte through the gap, forming an ultrathin ion channel. The two end faces of the conductor are in contact with the electrolyte inside the insulating tube and the external electrolyte, respectively.

2. A reference electrode with an ultrathin ion channel according to claim 1, characterized in that: The insulating tube is made of materials including glass, quartz, ceramic, or polymer.

3. A reference electrode with an ultrathin ion channel according to claim 1, characterized in that: The insulating and sealing materials include epoxy resin plugs, sealing films, silicone plugs, or heat-sealing tubes.

4. A reference electrode with an ultrathin ion channel according to claim 1, characterized in that: The internal reference electrode includes a silver-silver chloride electrode, a calomel electrode, a mercury-mercurous sulfate electrode, or a mercury-mercurous oxide electrode.

5. A reference electrode with an ultrathin ion channel according to claim 1, characterized in that: The electrolyte includes potassium chloride solution, sodium chloride solution, potassium sulfate solution, sodium sulfate solution, sulfuric acid solution, sodium hydroxide solution, or potassium hydroxide solution.

6. A reference electrode with an ultrathin ion channel according to claim 1, characterized in that: The conductor includes platinum, gold, silver, copper, palladium, rhodium, iridium, and alloy materials, as well as glassy carbon, carbon rods, carbon fibers, or conductive glass.

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