A polarization imaging detection method and apparatus for detecting the activity distribution of the hydrogen evolution reaction at an electrode.

Abstract

This application relates to the field of detection technology for characterizing electrode material properties, and particularly to a polarization imaging detection method and apparatus for the distribution of electrode hydrogen evolution reaction activity. The method includes the following steps: performing a calibration experiment on the electrode under test to determine the optimal incident wavelength and incident angle for detecting the polarization degree of the electrode; using the electrode under test as the working electrode, performing a linear scanning voltammetric test on the working electrode immersed in the electrolyte; simultaneously acquiring optical images during the linear scanning process; and obtaining the curve of polarization degree of the electrode surface changing with potential using the polarization degree calculation formula, thereby determining the distribution of the hydrogen evolution initiation potential of the electrode material, i.e., the distribution of electrode hydrogen evolution reaction activity. This application utilizes a polarization optical detection device combined with a potential scanning system to perform in-situ detection of electrode surface activity, which is not only simple to operate but also provides in-situ, real-time, and effective electrode activity distribution, providing a detection tool for electrode modification.

Description

Technical Field

[0001] This application relates to the field of detection technology for characterizing the properties of electrode materials, and in particular to a polarization imaging detection method and apparatus for detecting the distribution of the hydrogen evolution reaction activity of an electrode. Background Technology

[0002] Faced with a global energy crisis, society's demand for developing alternative energy sources is growing. Hydrogen, as a zero-emission energy carrier, can be efficiently produced not only through water electrolysis but also converted into electricity in fuel cells, providing a viable solution to the energy crisis. In research on hydrogen production through water electrolysis, traditional electrochemical characterization methods, such as cyclic voltammetry and electrochemical impedance spectroscopy, while providing quantitative information on the overall electrode reaction, highlight the crucial role of the electrode as a core component in the system. Its design and material selection significantly impact the overall system performance, efficiency, and cost. Electrode modification is a key technology for improving the efficiency of water electrolysis for hydrogen production, but these methods struggle to ensure uniform modification. Clearly, uneven modification can lead to greater polarization in the reaction. Therefore, the spatial distribution of the modified electrode's activity needs to be characterized to assess its effectiveness. Summary of the Invention

[0003] This application provides a polarization imaging detection method and apparatus for detecting the distribution of electrode hydrogen evolution reaction activity. By using a polarization optical detection device combined with a potential scanning system to detect the surface activity of the electrode in situ, it is not only easy to operate, but also can obtain in situ, real-time and effective electrode activity distribution, providing a detection tool for electrode modification.

[0004] To address the aforementioned technical problems, in a first aspect, embodiments of this application provide a polarization imaging detection method for the distribution of hydrogen evolution reaction activity on an electrode, comprising the following steps: First, a calibration experiment is performed on the electrode under test to determine the optimal incident light wavelength and incident angle for detecting the polarization degree of the electrode under test; then, the electrode under test is used as the working electrode in a potential scanning system, and a linear scanning voltammetry test is performed on the working electrode immersed in the electrolyte using the potential scanning system to obtain a linear scanning voltammetry curve; during the linear scanning process, an optical image is simultaneously acquired using a polarization imaging detection module; next, a pixel point on the image is randomly selected, and the curve of the change in polarization degree with potential at that position can be obtained according to the formula for calculating the polarization degree, thereby determining the starting potential at that point; finally, all positions on the optical image are traversed to obtain the distribution of the hydrogen evolution starting potential of the electrode material, i.e., the distribution of the hydrogen evolution reaction activity on the electrode.

[0005] In some exemplary embodiments, a calibration experiment is performed on the electrode under test, including: first, setting a series of different incident light wavelengths and different incident angles for the electrode material; then, performing a polarization imaging experiment on the first set of input incident light wavelengths and incident angles; during the experiment, a potential scanning system is used to perform linear scanning voltammetry tests on the electrode, while an imaging detection module acquires images of parallel polarization and perpendicular polarization; the average polarization degree of the entire image is calculated using the polarization degree formula, and a curve showing the change of the average polarization degree of the entire image with the potential is obtained, thus obtaining the average starting potential of the entire image; after measuring the first set, all the incident angles to be measured are tested under the first incident light wavelength by changing the incident angle; then, the incident light wavelength is changed, and all the incident angles to be measured are tested again to obtain the average starting potential of the entire image; after all parameter tests are completed, the average starting potential of the entire image obtained under different parameters is compared, and the set of incident light wavelengths and incident angles with the earliest change in starting potential is determined as the optimal incident light parameters for the electrode material under test.

[0006] In some exemplary embodiments, the formula for calculating the degree of polarization is:

[0007]

[0008] Among them, I H and I V These correspond to the light intensity values ​​of the linearly polarized components when the incident light is polarized at 0 degrees and 90 degrees, respectively. When the polarized light is fully polarized, the degree of polarization DoP is 1; when the polarized light is not fully polarized, the degree of polarization DoP is 0; when the degree of polarization DoP is between 0 and 1, it represents partially polarized light.

[0009] Secondly, this application also provides a polarization imaging detection device for the distribution of electrode hydrogen evolution reaction activity. The device employs the polarization imaging detection method described in the above embodiments. The polarization imaging detection device includes: an incident light module, an optical sensing module, an imaging detection module, and a potential scanning system module. The incident light module converts light emitted from a quasi-monochrome LED into linearly polarized light through a linear polarizer. The optical sensing module is a transparent window, with the electrode under test placed parallel to the window. It obtains information on the change in polarization degree by observing the change in the light scattering state caused by changes in the material on the electrode surface. The imaging detection module alternately acquires images of parallel and perpendicular polarization at the sensing interface. It obtains the starting potential of the electrode at the sensing interface from the synchronous relationship between the change in polarization degree and the voltage change. The potential scanning system module performs a linear scanning voltammetry test on the electrode under test, immersed in electrolyte, to study the change in the incident light scattering state caused by the redox reaction of the electrolyte at the electrode during the linear scanning voltammetry process.

[0010] In some exemplary embodiments, the incident light module includes a monochromatic LED, a collimating lens, and a polarizer; in the incident light module, the light emitted by the monochromatic LED is guided by an optical fiber, passes through the collimating lens and the polarizer to form linearly polarized light, and is incident on the optical sensing module.

[0011] In some exemplary embodiments, the monochrome LED is an XPE2 LED lamp, the collimating lens is a GCL-010650 collimating lens, and the polarizer is a GCL-050003 linear polarizer.

[0012] In some exemplary embodiments, the imaging detection module is used to acquire horizontally and vertically polarized images; the imaging detection module includes an electric filter wheel and a camera, wherein the electric filter wheel has built-in polarizers that are parallel and perpendicular to the incident light, respectively; the polarizers in the electric filter wheel and the polarizers in the incident light module are respectively formed as parallel polarization and perpendicular polarization, and the resulting images are then subjected to polarization degree calculation.

[0013] In some exemplary embodiments, the polarization imaging detection device further includes: an electrolytic cell and a three-electrode module disposed within the electrolytic cell; the three-electrode module includes a working electrode, a counter electrode, and a reference electrode; the electrolytic cell is filled with an electrolyte, such that the electrolyte immerses the working electrode, the counter electrode, and the reference electrode.

[0014] In some exemplary embodiments, the electrolyte is a 1 mol / L KOH solution, the counter electrode is a graphite rod, and the reference electrode is a saturated calomel electrode.

[0015] In some exemplary embodiments, the potential scanning system module is used to drive an electrochemical reaction. The change in the valence state of the electrolyte causes a hydrogen evolution reaction on the electrode surface, and the generated bubbles cause a change in the light scattering state, which in turn causes a change in the degree of polarization. The potential scanning system module uses a computer display to display the linear scanning voltammetric curve obtained by the potential scanning system and a series of parallel and perpendicular polarized images captured by the camera.

[0016] The technical solution provided in this application has at least the following advantages:

[0017] This application provides a polarization imaging detection method and apparatus for the distribution of hydrogen evolution reaction activity of an electrode. The method includes the following steps: First, a calibration experiment is performed on the electrode under test to determine the optimal incident light wavelength and incident angle for detecting the polarization degree of the electrode under test; then, the electrode under test is used as the working electrode in a potential scanning system, and a linear scanning voltammetry test is performed on the working electrode immersed in the electrolyte using the potential scanning system to obtain a linear scanning voltammetry curve; during the linear scanning process, an optical image is simultaneously acquired using a polarization imaging detection module; next, a pixel point on the image is randomly selected, and the curve of the change of polarization degree with potential at that position can be obtained according to the formula for calculating the polarization degree, thereby determining the starting potential at that point; finally, all positions on the optical image are traversed to obtain the distribution of the hydrogen evolution starting potential of the electrode material, i.e., the distribution of the hydrogen evolution reaction activity of the electrode.

[0018] The polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity provided in this application uses a potential scanning system to drive the electrode during linear scanning voltammetry testing, while a polarization optical detection device is used to detect changes in the electrolyte's participation in the redox reaction process on the electrode in real time. This process calculates the change in polarization state of the electrode surface by acquiring the changes in optical signals caused by changes in the scattering state of the electrode surface. The potential scanning system can obtain the voltage change curve of the entire process, and the hydrogen evolution initiation potential at a certain point is determined by determining the voltage at the point of polarization state change. This method is simple to operate, yet it can obtain in-situ, real-time, and effective electrode activity distribution, providing a detection tool for electrode modification. Attached Figure Description

[0019] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments, and unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0020] Figure 1 This is a schematic flowchart of a polarization imaging detection method for detecting the activity distribution of an electrode hydrogen evolution reaction, provided in an embodiment of this application.

[0021] Figure 2 This is a flowchart of a calibration test for electrode materials provided in an embodiment of this application.

[0022] Figure 3 This is a schematic diagram of a polarization optical detection device for in-situ detection of electrode activity distribution provided in an embodiment of this application.

[0023] Figure 4 This is a schematic diagram of the structure of the in-situ detection device for the active area of ​​the water electrolysis electrode by the polarization optical detection device during the linear scanning voltammetry process provided in the embodiments of this application.

[0024] Figure 5This is a schematic diagram of image acquisition using an imaging detection module during the water electrolysis reaction process provided in an embodiment of this application.

[0025] Figure 6 This is a schematic diagram of image processing using an imaging detection module during the water electrolysis reaction process provided in an embodiment of this application.

[0026] Figure 7 The electrolysis hydrogen evolution initiation potential distribution diagrams for different copper electrode materials provided in the embodiments of this application, obtained in a 1 mol / L KOH solution at a potential scan rate of 1 mV / s.

[0027] Among them, Figure 4 In the diagram, 11 is a monochrome LED, 12 is a collimating lens, 13 is a polarizer, 21 is a glass window, 22 is an electrolytic cell, 31 is an electric filter wheel, 32 is a camera, 41 is a working electrode, 42 is a counter electrode, 43 is a reference electrode, 44 is a potential scanning system, and 45 is a computer. Detailed Implementation

[0028] As the background technology shows, current electrode modification methods struggle to ensure uniformity of the modification. Clearly, uneven modification can actually lead to greater polarization during the reaction.

[0029] Methods for characterizing electrode activity distribution include optical imaging techniques, scanning probe techniques, in-situ Raman spectroscopy, and in-situ X-ray absorption spectroscopy. Each of these methods has its own advantages and disadvantages: optical imaging techniques are intuitive but have limited spatial resolution; scanning probe techniques provide high spatial resolution but may damage the sample; in-situ Raman spectroscopy may have reduced signal accuracy due to fluorescence interference; and in-situ X-ray absorption spectroscopy has strict requirements on sample concentration and homogeneity and is complex to analyze.

[0030] Related technologies propose an online detection method and device for the distribution of activity in water electrolysis electrode reactions and an online detection method and device for the activity of hydrogen evolution / oxygen evolution reaction catalysts, respectively utilizing total internal reflection imaging technology to characterize the activity of water electrolysis electrodes and catalyst-supported electrodes. However, during the process, the total internal reflection detection technology requires the tested electrode to be in close contact with the prism surface, which severely affects the diffusion of electrolyte and bubbles on the electrode surface; at the same time, this technology has a certain lag in the detection of bubbles.

[0031] To address the aforementioned technical problems, this application provides a polarization imaging detection method and apparatus for the distribution of electrode hydrogen evolution reaction activity. The method includes the following steps: First, a calibration experiment is performed on the electrode under test to determine the optimal incident wavelength and incident angle for detecting the polarization degree of the electrode. Then, the electrode under test is used as the working electrode in a potential scanning system, and a linear scanning voltammetry test is performed on the working electrode immersed in the electrolyte using the potential scanning system to obtain a linear scanning voltammetry curve. During the linear scanning process, an optical image is simultaneously acquired using a polarization imaging detection module. Next, a pixel is randomly selected on the image, and the curve of the polarization degree changing with potential at that location is obtained according to the formula for calculating the polarization degree, thereby determining the starting potential at that point. Finally, the distribution of the starting potential for hydrogen evolution of the electrode material, i.e., the distribution of electrode hydrogen evolution reaction activity, is obtained by traversing all positions on the optical image. This application provides a polarization imaging detection method and apparatus for the distribution of electrode hydrogen evolution reaction activity. By utilizing a polarization optical detection device combined with a potential scanning system to perform in-situ detection of electrode surface activity, it is not only simple to operate but also provides in-situ, real-time, and effective electrode activity distribution, offering a detection tool for electrode modification.

[0032] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0033] See Figure 1 This application provides a polarization imaging detection method for the distribution of activity in the hydrogen evolution reaction of an electrode, comprising the following steps:

[0034] Step S1: Perform a calibration experiment on the electrode under test to determine the optimal incident light wavelength and incident angle for detecting the polarization degree of the electrode under test.

[0035] Step S2: Use the electrode under test as the working electrode in the potential scanning system, and use the potential scanning system to perform a linear scanning voltammetry test on the working electrode immersed in the electrolyte to obtain a linear scanning voltammetry curve; during the linear scanning process, optical images are simultaneously acquired using a polarization imaging detection module.

[0036] Step S3: Randomly select a pixel on the image, and according to the formula for calculating the degree of polarization, obtain the curve of the degree of polarization at that position as a function of potential, thereby determining the starting potential of that point.

[0037] Step S4: Traverse all positions on the optical image to obtain the distribution of the hydrogen evolution initiation potential of the electrode material, i.e., the distribution of the electrode hydrogen evolution reaction activity.

[0038] The polarization imaging detection method for the activity distribution of the hydrogen evolution reaction in electrodes provided in this application mainly utilizes a potential scanning system (such as an electrochemical workstation) and a polarization optical detection device to simultaneously perform in-situ detection of the electrochemical reaction of the electrode, thereby obtaining the onset potential distribution on the electrode surface. When the hydrogen evolution reaction occurs, the generation of bubbles on the electrode surface changes the light scattering state, thus altering the degree of polarization. By observing the change in polarization, the hydrogen evolution onset potential distribution of the electrode, i.e., the electrode activity distribution, can be obtained. This method is simple to operate yet can obtain in-situ, real-time, and effective electrode activity distribution, providing a detection tool for electrode modification.

[0039] Polarization optical detection methods possess advantages such as high sensitivity, high resolution, and in-situ non-destructive testing. They can detect changes in polarization at interfaces in real time and provide real-time imaging of the activity distribution on the surface of electrochemical reaction electrodes. Therefore, this application utilizes a polarization optical detection device combined with a potential scanning system for in-situ detection of electrode surface activity. This not only solves the problem of electrolyte and bubble diffusion but also eliminates the influence of prisms, achieving higher sensitivity.

[0040] This application uses water electrolysis electrode materials as an example to study the in-situ detection process of electrode material activity distribution. A polarization optics detection device is selected to detect the scattering state of light on the electrode surface during potential scanning, thereby obtaining the change in polarization degree. Combined with the voltage change obtained from the potential scanning system, the electrode's initiation potential distribution is finally obtained to characterize the electrode's activity distribution. This application provides a technical tool for characterizing the activity distribution of electrodes participating in electrochemical reactions.

[0041] This application proposes an in-situ detection method for measuring the distribution of electrode activity in electrochemical reactions. During linear scanning voltammetry testing using a potential scanning system to drive the electrode, a polarization optical detection device is used to monitor the changes in the electrolyte's participation in the redox reaction process on the electrode in real time. This process calculates the change in polarization state of the electrode surface by acquiring the optical signal changes caused by the changes in the scattering state of the electrode surface. The potential scanning system can obtain the voltage change curve of the entire process, and the hydrogen evolution initiation potential at a certain point is determined by determining the voltage at which the polarization state changes. Specifically, a beam of obliquely incident polarized light emitted from the light source module penetrates the window and a certain buffer depth of electrolyte to reach the electrode surface and is reflected. The reflected light is then scattered by bubbles of various sizes in the solution, changing the polarization state of the emitted light. Different bubble sizes result in different scattering effects on the incident polarized light; larger bubbles have a more pronounced scattering effect, leading to significant changes in the polarization state in local areas. Furthermore, for a specific material surface, the wavelength and angle of incident light also significantly affect the polarization state of the light. Therefore, before formally testing new electrode materials, calibration experiments are required to find the incident light wavelength and incident angle that have the highest sensitivity to the polarization state transition of the material.

[0042] like Figure 2 As shown, in some embodiments, step S1 involves a calibration experiment on the electrode under test, including: first, setting a series of different incident light wavelengths and different incident angles for the electrode material; then, performing a polarization imaging experiment on the first set of input incident light wavelengths and incident angles; during the experiment, using a potential scanning system to perform linear scanning voltammetry tests on the electrode, while simultaneously acquiring images of parallel polarization and perpendicular polarization by an imaging detection module; calculating the average polarization degree of the entire image using the polarization degree formula, and obtaining the curve of the average polarization degree of the entire image changing with potential, thus obtaining the average starting potential of the entire image; after measuring the first set, by changing the incident angle, testing all the incident angles to be measured under the first incident light wavelength; then changing the incident light wavelength and continuing to test all the incident angles to be measured, thus obtaining the average starting potential of the entire image; after all parameter tests are completed, comparing the average starting potential of the entire image obtained under different parameters, and determining the set of incident light wavelengths and incident angles with the earliest change in starting potential as the optimal incident light parameters for the electrode material under test.

[0043] In some embodiments, in step S2, the electrode under test is used as the working electrode in the potential scanning system, and the potential scanning system is used to perform a linear scanning voltammetry test on the working electrode immersed in the electrolyte to obtain a linear scanning voltammetry curve; in step S2, during the linear scanning process, an optical image is simultaneously acquired using a polarization imaging detection module.

[0044] Polarization refers to the phenomenon where the direction of light vibration is asymmetrical to the direction of light propagation. The polarization characteristics of incident light hitting an object and reflected light are both related to the object's inherent properties. To describe the change in polarization state, this application introduces a formula for the degree of polarization (DoP):

[0045]

[0046] In the above formula, I H and I V These correspond to the light intensity values ​​of the linearly polarized state components when the polarization angle is 0 degrees and 90 degrees relative to the incident linearly polarized light, respectively. When the polarized light is fully polarized, the degree of polarization (DoP) is 1; when the polarized light is partially polarized (natural light), the degree of polarization (DoP) is 0; when the degree of polarization (DoP) is between 0 and 1, it represents partially polarized light. Therefore, this application uses the degree of polarization to quantitatively represent the change in polarization state.

[0047] This application employs a polarization imaging detection module to acquire optical images, and simultaneously uses a potential scanning system to perform linear scanning voltammetry tests on the electrodes, obtaining linear scanning voltammetry curves, with the horizontal axis representing the voltage applied to the electrodes. Simultaneously, the valence state changes of active substances in the electrolyte on the electrodes generate bubbles, causing changes in the light scattering state on the electrode surface, which are reflected in the change of the central polarization degree of the signal detected by the optical sensor. By analyzing the relationship between the change in polarization degree signal and the voltage change, the magnitude of the initiation potential can be obtained, thus revealing the initiation potential distribution of the electrodes. This provides a novel method for in-situ detection of electrode activity distribution.

[0048] The polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity provided in this application will be described in detail below through specific embodiments. The steps of the method are as follows:

[0049] The first step is to transfer the electrode to be tested as the working electrode into the potential scanning system module and immerse it in the electrolyte. Place it vertically in the electrolyte and face the lens. Then, assemble the module into the optical path of the detection device.

[0050] The second step is to adjust the polarization optical detection device so that the incident polarized light is obliquely incident on the electrode surface, and to position the camera with the polarization wheel perpendicularly to the surface of the electrode to be tested in the electrolytic cell.

[0051] The third step is to debug the polarization optical detection device, conduct calibration experiments, and determine the incident light wavelength and incident angle that are most sensitive to changes in the polarization degree of the electrode surface under test.

[0052] The fourth step involves using a potential scanning system to perform linear scanning voltammetry on the electrodes immersed in the electrolyte, obtaining linear scanning voltammetry curves. Simultaneously, a polarization optics detection device acquires images of parallel and perpendicular polarization over time.

[0053] Fifth step, according to the formula for calculating the degree of polarization. This yielded curves showing the change in polarization degree with potential at various positions on a series of parallel and perpendicular polarized images.

[0054] The sixth step is to obtain the polarization degree of the electrode when the hydrogen evolution reaction occurs by setting a variable reference value, namely a certain standard deviation of the polarization degree on the platform before the water electrolysis reaction occurs.

[0055] The seventh step involves identifying the initiation potential at a given location based on the curve showing the change in polarization degree with potential. By iteratively determining the initiation potential at each location, the distribution of hydrogen evolution initiation potentials on the electrode surface can be obtained.

[0056] See Figure 3 This application also provides a polarization imaging detection device for detecting the distribution of electrode hydrogen evolution reaction activity. The device employs the aforementioned polarization imaging detection method for detecting the distribution of electrode hydrogen evolution reaction activity. The polarization imaging detection device includes: an incident light module, an optical sensing module, an imaging detection module, and a potential scanning system module. The incident light module converts light emitted from a quasi-monochrome LED into linearly polarized light through a linear polarizer. The optical sensing module is a transparent window, with the electrode under test placed parallel to the window. It obtains information on the change in polarization degree by observing the change in the light scattering state caused by changes in the material on the electrode surface. The imaging detection module alternately acquires images of parallel and perpendicular polarization at the sensing interface. It obtains the starting potential of the electrode at the sensing interface from the synchronous relationship between the change in polarization degree and the voltage change. The potential scanning system module performs a linear scanning voltammetry test on the electrode under test, which is immersed in electrolyte, to study the change in the incident light scattering state caused by the redox reaction of the electrolyte at the electrode during the linear scanning voltammetry process.

[0057] Figure 4 This is a system example that utilizes a polarization optics detection device to detect the in-situ distribution of the activity of electrodes participating in electrochemical reactions during a linear scan voltammetry process. For example... Figure 4 As shown, in some embodiments, the incident light module includes: a monochromatic LED 11, a collimating lens 12, and a polarizer 13; in the incident light module, the light emitted by the monochromatic LED 11 is guided by an optical fiber, passes through the collimating lens 12 and the polarizer 13 to form linearly polarized light, and is incident on the optical sensing module.

[0058] In some embodiments, the monochrome LED 11 is an XPE2 LED, the collimating lens 12 is a GCL-010650 collimating lens, and the polarizer 13 is a GCL-050003 linear polarizer.

[0059] like Figure 4As shown, in the incident light module, the light emitted by the monochromatic LED 11 is guided by an optical fiber, passes through a collimating lens 12 and a polarizer 13 to form linearly polarized light, and then incident on the optical sensing module. After scattering at the interface between the glass window 21 and the working electrode 41, the imaging detection module acquires horizontally and vertically polarized images.

[0060] In some embodiments, the imaging detection module is used to acquire horizontally and vertically polarized images; please continue reading. Figure 4 The imaging detection module includes an electric filter wheel 31 and a camera 32. The electric filter wheel 31 has built-in polarizers that are parallel and perpendicular to the incident light, respectively. The polarizers in the electric filter wheel 31 and the polarizers in the incident light module are respectively parallel and perpendicular to the polarizers, and the polarization degree of the obtained image is calculated.

[0061] Specifically, the motorized filter wheel 31 can be the ZWO EFW-mini model motorized filter wheel, and the camera 32 can be the ZWO ASI183MM-P camera.

[0062] In some embodiments, the polarization imaging detection device further includes an electrolytic cell 22 and a three-electrode module disposed within the electrolytic cell 22; the three-electrode module includes a working electrode 41 (electrode to be tested), a counter electrode 42, and a reference electrode 43; the electrolytic cell 22 is filled with an electrolyte, such that the electrolyte immerses the working electrode 41, the counter electrode 42, and the reference electrode 43.

[0063] In some embodiments, the electrolyte is a 1 mol / L KOH solution, the counter electrode is a graphite rod, and the reference electrode is a saturated calomel electrode.

[0064] In some exemplary embodiments, the potential scanning system module is used to drive an electrochemical reaction. Changes in the valence state of the electrolyte cause a hydrogen evolution reaction on the electrode surface, and the generated bubbles alter the light scattering state, leading to a change in polarization. The potential scanning system 44 uses a computer display to show the linear scanning voltammetric curve obtained by the potential scanning system and a series of parallel and perpendicular polarized images captured by a camera, such as... Figure 4 As shown, computer 45 receives polarization images and current-voltage curves.

[0065] Figure 5 This is an example of an imaging detection module acquiring images during the water electrolysis reaction process. Figure 5 The sequence of image acquisition by the imaging detection module is as follows: A linear scanning voltammetry test is performed on the electrode immersed in the electrolyte using a potential scanning system, while the imaging detection module alternately acquires parallel-polarized and perpendicular-polarized images that change over time.

[0066] Figure 6 This is an example of image processing performed by an imaging detection module during the water electrolysis reaction. Figure 6 (a) To utilize the polarization degree formula Process adjacent parallel and perpendicular polarized images. Figure 6 (b) The image obtained by subtracting the polarization degree image obtained in subsequent processing from the polarization degree image obtained in the first group and taking the absolute value. Figure 6 (c) is a curve showing the change in polarization degree at a randomly selected point on the image as a function of potential. It can be seen that during the reaction process, the polarization degree at each point first experiences a plateau before a step change. The starting potential of the step change (point A) is defined as the hydrogen evolution initiation potential.

[0067] Figure 7 This is an example of the potential distribution of hydrogen evolution in electrolysis in water obtained by different copper electrode materials in 1 mol / L KOH solution at a potential scan rate of 1 mV / s. Figure 7 (a) is a copper plate initiation potential distribution diagram with different proportions of RuO2 and Co3O4 catalysts (the last row is unloaded catalyst). Figure 7 In (a), the Ru:Co feed ratios in each column from left to right are 1:2, 1:4, 1:6 and 1:8. It can be clearly seen that the catalytic activities of RuO2 and Co3O4 catalysts with different ratios are very different. Figure 7 (b) is the starting potential distribution diagram of a single-layer copper mesh without catalyst loading. It can be seen that the hydrogen evolution reaction of water electrolysis is distributed on the copper mesh, which also confirms the reliability and accuracy of the device for detecting the activity distribution of electrode materials.

[0068] Based on the above technical solutions, this application provides a polarization imaging detection method and apparatus for the distribution of electrode hydrogen evolution reaction activity. The method includes the following steps: First, a calibration experiment is performed on the electrode under test to determine the optimal incident light wavelength and incident angle for detecting the polarization degree of the electrode under test; then, the electrode under test is used as the working electrode in a potential scanning system, and a linear scanning voltammetry test is performed on the working electrode immersed in the electrolyte using the potential scanning system to obtain a linear scanning voltammetry curve; during the linear scanning process, an optical image is simultaneously acquired using a polarization imaging detection module; next, a pixel point on the image is randomly selected, and the curve of the change of polarization degree with potential at that position can be obtained according to the formula for calculating the polarization degree, thereby determining the starting potential at that point; finally, all positions on the optical image are traversed to obtain the distribution of the starting potential of hydrogen evolution of the electrode material, i.e., the distribution of electrode hydrogen evolution reaction activity.

[0069] The polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity provided in this application uses a potential scanning system to drive the electrode during linear scanning voltammetry testing, while a polarization optical detection device is used to detect changes in the electrolyte's participation in the redox reaction process on the electrode in real time. This process calculates the change in polarization state of the electrode surface by acquiring the changes in optical signals caused by changes in the scattering state of the electrode surface. The potential scanning system can obtain the voltage change curve of the entire process, and the hydrogen evolution initiation potential at a certain point is determined by determining the voltage at the point of polarization state change. This method is simple to operate, yet it can obtain in-situ, real-time, and effective electrode activity distribution, providing a detection tool for electrode modification.

[0070] Those skilled in the art will understand that the above-described embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this application. Any person skilled in the art can make their own modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A polarization imaging detection method for the distribution of activity in an electrode hydrogen evolution reaction, characterized in that, Includes the following steps: A calibration experiment was conducted on the electrode under test to determine the optimal incident light wavelength and incident angle for detecting the polarization degree of the electrode under test. Using the electrode under test as the working electrode, a linear sweep voltammetry test was performed on the working electrode immersed in the electrolyte to obtain the linear sweep voltammetry curve. Optical images are acquired simultaneously during the linear scanning process; By randomly selecting a pixel in the image and using the formula for calculating the degree of polarization, the curve of the degree of polarization at that location as a function of potential can be obtained, thereby determining the starting potential at that point. By traversing all positions on the optical image, the distribution of the hydrogen evolution initiation potential of the electrode material is obtained, that is, the distribution of the electrode hydrogen evolution reaction activity. The calibration experiment for the electrode under test includes: First, a series of different incident light wavelengths and different incident angles are set for the electrode material; A polarization imaging experiment was conducted on the incident light wavelength and incident angle of the first set of inputs. During the experiment, a potential scanning system was used to perform linear scanning voltammetry tests on the electrodes, while an imaging detection module acquired images of parallel polarization and vertical polarization. The average polarization degree of the entire image is calculated using the polarization degree formula, and the curve of the average polarization degree of the entire image as a function of potential is obtained, thus yielding the average starting potential of the entire image. After measuring the first group, the incident angle was changed to test all the incident angles under the first incident light wavelength; then the incident light wavelength was changed to continue testing all the incident angles to be measured, and the average starting potential of the whole picture was obtained. After all parameters have been tested, the average starting potential of the whole image obtained under different parameters is compared, and the incident light wavelength and incident angle of the group of incident light with the earliest change in starting potential are determined as the optimal incident light parameters of the electrode material to be tested. The formula for calculating the degree of polarization is: Among them, I H and I V These correspond to the light intensity values ​​of the linearly polarized components when the incident light is polarized at 0 degrees and 90 degrees, respectively. When the polarized light is fully polarized, the degree of polarization DoP is 1; when the polarized light is not fully polarized, the degree of polarization DoP is 0; when the degree of polarization DoP is between 0 and 1, it represents partially polarized light.

2. The polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity according to claim 1, characterized in that, This method employs a polarization imaging detection device, which includes: The system comprises an incident light module, an optical sensing module, an imaging detection module, and a potential scanning system module; among which, The incident light module is used to convert the light emitted by the quasi-monochrome LED into linearly polarized light through a linear polarizer. The optical sensing module is a transparent window, and the electrode under test is placed parallel to the window; the change in polarization degree is obtained by the change in the scattering state of light caused by the change in the material on the electrode surface. The imaging detection module is used to alternately acquire images of parallel polarization and vertical polarization of the sensing interface; the starting potential of the electrode at the sensing interface is obtained from the curve of polarization degree as a function of potential. The potential scanning system module is used to study how the redox reaction of the electrolyte at the electrode changes the scattering state of incident light during the linear scanning voltammetry test on the electrode immersed in electrolyte.

3. The polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity according to claim 2, characterized in that, The incident light module includes: a monochrome LED, a collimating lens, and a polarizer; In the incident light module, the light emitted by the monochromatic LED is guided by the optical fiber, passes through the collimating lens and polarizer to form linearly polarized light, and then enters the optical sensing module.

4. The polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity according to claim 3, characterized in that, The monochrome LED is an XPE2 LED, the collimating lens is a GCL-010650 collimating lens, and the polarizer is a GCL-050003 linear polarizer.

5. The polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity according to claim 2, characterized in that, The imaging detection module is used to acquire images with horizontal and vertical polarization. The imaging detection module includes an electric filter wheel and a camera. The electric filter wheel has built-in polarizers that are parallel and perpendicular to the incident light, respectively. The polarizers in the electric filter wheel and the polarizers in the incident light module are respectively parallel and perpendicular to each other, and the resulting image is then subjected to polarization degree calculation.

6. The polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity according to claim 2, characterized in that, Also includes: An electrolytic cell and a three-electrode module disposed within the electrolytic cell; The three-electrode module includes a working electrode, a counter electrode, and a reference electrode; The electrolytic cell is filled with electrolyte, which immerses the working electrode, counter electrode, and reference electrode.

7. The polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity according to claim 6, characterized in that, The electrolyte is a 1 mol / L KOH solution, the counter electrode is a graphite rod, and the reference electrode is a saturated calomel electrode.

8. The polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity according to claim 2, characterized in that, The potential scanning system module is used to drive the electrochemical reaction. The change in the valence state of the electrolyte causes a hydrogen evolution reaction on the electrode surface. The generated bubbles cause a change in the light scattering state, which in turn causes a change in the degree of polarization. The potential scanning system module uses a computer monitor to display the linear scanning volt-ampere curve obtained by the potential scanning system and a series of parallel and vertically polarized images captured by the camera.

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