Polarization imaging detection method and device for electrode hydrogen evolution reaction activity distribution

Abstract

The invention relates to the technical field of detection of electrode material performance characterization, in particular to a polarization imaging detection method and device for electrode hydrogen evolution reaction activity distribution.The method comprises the following steps that a calibration experiment is conducted on a to-be-detected electrode, and the optimal incident light wavelength and incident angle for detection of the polarization degree of the to-be-detected electrode are determined; taking the electrode to be tested as a working electrode, and carrying out linear scanning volt-ampere test on the working electrode immersed in the electrolyte; in the linear scanning process, optical images are collected at the same time; and obtaining a change curve of the polarization degree of the electrode surface along with the potential through a calculation formula of the polarization degree so as to determine the distribution of the hydrogen evolution starting potential of the electrode material, namely the hydrogen evolution reaction activity distribution of the electrode. The polarization optical detection device is combined with the potential scanning system to perform in-situ detection on the surface activity of the electrode, so that the operation is simple and convenient, in-situ, real-time and effective electrode activity distribution can be obtained, and a detection tool is provided for electrode modification.

Description

Technical Field

[0001] The present application relates to the technical field of detection of electrode material performance characterization, and in particular to a polarization imaging detection method and device for electrode hydrogen evolution reaction activity distribution. Background Art

[0002] Faced with the global energy crisis, society has an increasing demand for the development of alternative energy sources. Hydrogen, as a zero-emission energy carrier, can not only be efficiently produced through the water electrolysis process, but can also be converted into electrical energy in fuel cells, providing a feasible way to solve the energy crisis. In the study of hydrogen production by water electrolysis, traditional electrochemical characterization methods, such as cyclic voltammetry and electrochemical impedance spectroscopy, can provide quantitative information about the electrode reaction as a whole. However, as the core component in the water electrolysis hydrogen production system, the design and material selection of the electrode have a decisive influence on the performance, efficiency and cost of the entire system. Electrode modification of water electrolysis is a key technology to improve the efficiency of hydrogen production by water electrolysis. These electrode modification methods are difficult to ensure the uniformity of the modification. Obviously, if the modification is unevenly distributed, it will cause greater polarization in the reaction. Therefore, the active space distribution after electrode modification needs to be characterized in order to measure its effectiveness. Summary of the invention

[0003] The embodiments of the present application provide a polarization imaging detection method and device for the distribution of electrode hydrogen evolution reaction activity. By using a polarization optical detection device in combination with a potential scanning system to perform in-situ detection of electrode surface activity, 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] In order to solve the above technical problems, in the first aspect, the embodiment of the present application provides a polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity, comprising the following steps: first, a calibration experiment is performed on the electrode to be tested to determine the optimal incident light wavelength and incident angle for detecting the polarization degree of the electrode to be tested; then, the electrode to be tested is used as a working electrode in a potential scanning system, and a linear scanning voltammetry test is performed on the working electrode immersed in an electrolyte using the potential scanning system to obtain a linear scanning voltammetry curve; during the linear scanning process, an optical image is simultaneously collected using a polarization imaging detection module; next, a pixel point on the image is randomly selected, and a curve of the polarization degree changing with the potential at the position can be obtained according to a calculation formula for the polarization degree, so as to determine the starting potential of the point; finally, all positions on the optical image are traversed to obtain the distribution of the hydrogen evolution starting potential of the electrode material, that is, the distribution of the electrode hydrogen evolution reaction activity.

[0005] In some exemplary embodiments, a calibration experiment is performed on the electrode to be tested, 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 group of input incident light wavelengths and incident angles; during the experiment, a potential scanning system is used to perform a linear scanning voltammetric test on the electrode, and the imaging detection module simultaneously collects images of parallel polarization and vertical polarization; the average polarization degree of the entire image is calculated using a polarization degree formula, and a curve of the average polarization degree of the entire image versus potential is obtained to obtain an average starting potential of the entire image; after measuring the first group, all incident angles to be tested under the first incident light wavelength are tested by changing the incident angle; then, the incident light wavelength is changed, and all incident angles to be tested are continued to be tested to obtain an 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 group 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 to be tested.

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

[0007]

[0008] Among them, I H and I V They correspond to the intensity values ​​of the linear polarization state components when they are 0 degrees and 90 degrees to the incident linear polarized light respectively; when the polarized light is completely polarized light, the degree of polarization DoP is 1; when the polarized light is not completely polarized light, the degree of polarization DoP is 0; when the degree of polarization DoP is between 0 and 1, it indicates partially polarized light.

[0009] In a second aspect, an embodiment of the present application further provides a polarization imaging detection device for the distribution of electrode hydrogen evolution reaction activity, which uses the polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity described in the above embodiment for detection, and the polarization imaging detection device includes: an incident light module, an optical sensing module, an imaging detection module and a potential scanning system module; wherein the incident light module is used to convert the light emitted by a quasi-monochromatic LED into linear polarized light through a linear polarizer; the optical sensing module is a transparent window, and the electrode to be tested is placed parallel to the window; the change in polarization degree information is obtained by changing the scattering state of light caused by the material change on the electrode surface; the imaging detection module is used to alternately collect 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 synchronous relationship between the change in polarization degree and the change in voltage; the potential scanning system module is used to perform a linear scanning voltammetry test on the electrode to be tested immersed in an electrolyte, and study the redox reaction of the electrolyte at the electrode during the linear scanning voltammetry process that causes the scattering state of the incident light to change.

[0010] In some exemplary embodiments, the incident light module includes: a monochromatic LED, a collimating lens and a polarizer; in the incident light module, light emitted by the monochromatic LED is guided out 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 monochromatic 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 is equipped with polarizers that are parallel and perpendicular to the incident light, respectively; the polarizer in the electric filter wheel and the polarizer in the incident light module are respectively formed into parallel polarization and perpendicular polarization, and the obtained image is thereby subjected to polarization degree calculation.

[0013] In some exemplary embodiments, the polarization imaging detection device also includes: an electrolytic cell and a three-electrode module disposed in 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 so 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, and the change in the valence state of the electrolyte causes a hydrogen evolution reaction to occur on the electrode surface. The generated bubbles cause a change in the scattering state of light and then cause a change in the polarization degree; 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 polarization and vertical polarization images captured by the camera.

[0016] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0017] The embodiment of the present application provides a polarization imaging detection method and device for the distribution of electrode hydrogen evolution reaction activity, the method comprising the following steps: first, a calibration experiment is performed on the electrode to be tested to determine the optimal incident light wavelength and incident angle for detecting the polarization degree of the electrode to be tested; then, the electrode to be tested is used as a working electrode in a potential scanning system, and a linear scanning voltammetry test is performed on the working electrode immersed in an electrolyte by using the potential scanning system to obtain a linear scanning voltammetry curve; during the linear scanning process, an optical image is simultaneously collected by using a polarization imaging detection module; next, a pixel point on the image is randomly selected, and a curve of the polarization degree changing with the potential at the position can be obtained according to a calculation formula for the polarization degree, so as to determine the starting potential of the point; finally, all positions on the optical image are traversed to obtain the distribution of the hydrogen evolution starting potential of the electrode material, that is, the distribution of the electrode hydrogen evolution reaction activity.

[0018] The polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity provided by the present application uses a potential scanning system to drive the electrode to perform a linear scanning voltammetric test, and uses a polarization optical detection device to detect in real time the changes in the electrolyte on the electrode participating in the redox reaction process. This process calculates the change in the polarization state of the electrode surface by collecting the change in the optical signal caused by the change in the scattering state of the electrode surface. The potential scanning system can obtain the voltage change curve of the entire process, and determine the hydrogen evolution starting potential at a certain location by determining the voltage when the polarization state changes. This method is simple to operate, but can obtain in-situ, real-time, and effective electrode activity distribution, providing a detection tool for electrode modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0020] Figure 1 A schematic flow chart of a polarization imaging detection method for the activity distribution of an electrode hydrogen evolution reaction provided in an embodiment of the present application.

[0021] Figure 2 A flow chart of a calibration test for electrode materials provided in an embodiment of the present application.

[0022] Figure 3 A schematic diagram of a module of a polarization optical detection device for in-situ detection of electrode activity distribution provided in an embodiment of the present application.

[0023] Figure 4 A schematic structural diagram of a device for in-situ detection of the active area of ​​an electrolytic water electrode by a polarization optical detection device during a linear sweep voltammetry process provided in an embodiment of the present application.

[0024] Figure 5A schematic diagram of using an imaging detection module to collect images during the water electrolysis reaction process provided in an embodiment of the present application.

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

[0026] Figure 7 This is a starting potential distribution diagram of hydrogen evolution during water electrolysis obtained with different copper electrode materials provided in the embodiments of the present application in a 1 mol / L KOH solution at a potential scanning rate of 1 mV / s.

[0027] Among them, Figure 4 In the figure, 11 is a monochromatic 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 DESCRIPTION

[0028] As can be seen from the background technology, it is difficult to ensure the uniformity of the modification of the electrode in the current method. Obviously, if the modification is unevenly distributed, it will cause greater polarization in the reaction.

[0029] Methods for characterizing the distribution of electrode activity include optical imaging technology, scanning probe technology, in-situ Raman spectroscopy, in-situ X-ray absorption spectroscopy, etc. These methods have their own advantages and disadvantages: optical imaging technology is intuitive but has limited spatial resolution; scanning probe technology provides high spatial resolution but may damage the sample; in-situ Raman spectroscopy may reduce signal accuracy due to fluorescence interference; in-situ X-ray absorption spectroscopy has strict requirements on sample concentration and uniformity, and the analysis is complex.

[0030] Related technologies propose an online detection method and device for the distribution of the activity of the water electrolysis electrode reaction and an online detection method and device for the activity of the hydrogen / oxygen evolution reaction catalyst, respectively using total reflection imaging technology to characterize the activity of the water electrolysis electrode and the electrode loaded with the catalyst. However, in the process, since the total reflection detection technology requires the electrode to be closely attached to the prism surface, it will seriously affect the diffusion of the electrolyte and bubbles on the electrode surface; at the same time, this technology has a certain hysteresis in the determination of bubbles.

[0031] In order to solve the above technical problems, the embodiment of the present application provides a polarization imaging detection method and device for the distribution of electrode hydrogen evolution reaction activity, which includes the following steps: first, a calibration experiment is performed on the electrode to be tested to determine the incident light wavelength and incident angle that are optimal for detecting the polarization degree of the electrode to be tested; then, the electrode to be tested is used as the working electrode in the potential scanning system, and the working electrode immersed in the electrolyte is subjected to a linear scanning voltammetric test using the potential scanning system to obtain a linear scanning voltammetric curve; during the linear scanning process, the polarization imaging detection module is used to collect optical images at the same time; next, a pixel point on the image is randomly selected, and according to the calculation formula of the polarization degree, the curve of the polarization degree at the position with the potential change can be obtained, so as to determine the starting potential of the point; finally, all positions on the optical image are traversed to obtain the distribution of the starting potential of the electrode material for hydrogen evolution, that is, the distribution of the activity of the electrode hydrogen evolution reaction. The embodiment of the present application provides a polarization imaging detection method and device for the distribution of the activity of the electrode hydrogen evolution reaction, which detects the surface activity of the electrode in situ by using a polarization optical detection device combined with a potential scanning system, which is not only simple to operate, but also can obtain in situ, real-time and effective electrode activity distribution, providing a detection tool for electrode modification.

[0032] The following will describe the various embodiments of the present application in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present application, many technical details are provided in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solution claimed in the present application can be implemented.

[0033] See also Figure 1 The present application embodiment provides a polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity, comprising the following steps:

[0034] Step S1, performing a calibration experiment on the electrode to be tested to determine the optimal incident light wavelength and incident angle for polarization degree detection of the electrode to be tested.

[0035] Step S2: using the electrode to be tested as the working electrode in the potential scanning system, and using 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, simultaneously using the polarization imaging detection module to collect optical images.

[0036] Step S3: randomly select a pixel point on the image, and obtain a curve of the change of the degree of polarization versus the potential at the position according to the calculation formula of the degree of polarization, so as to determine the starting potential of the point.

[0037] Step S4, traversing all positions on the optical image to obtain the distribution of the hydrogen evolution starting potential of the electrode material, that is, the distribution of the electrode hydrogen evolution reaction activity.

[0038] The polarization imaging detection method for the distribution of the activity of the electrode hydrogen evolution reaction provided in the present application mainly uses a potential scanning system (such as an electrochemical workstation) and a polarization optical detection device to simultaneously detect the electrode electrochemical reaction in situ, thereby obtaining the process of the electrode surface starting potential distribution. When the hydrogen evolution reaction occurs, the generation of bubbles on the electrode surface will change the scattering state of light and thus change the degree of polarization. Through the change in the degree of polarization, the hydrogen evolution starting potential distribution of the electrode, that is, the activity distribution of the electrode, is obtained. This method is simple to operate, but can obtain in-situ, real-time, and effective electrode activity distribution, providing a detection tool for electrode modification.

[0039] The polarization optical detection method has the characteristics of high sensitivity, high resolution and in-situ non-destructive detection. It can detect the change of polarization degree at the interface in real time and can image the distribution of electrode surface activity in real time. Therefore, the present application uses a polarization optical detection device combined with a potential scanning system to detect the electrode surface activity in situ, which not only solves the diffusion problem of electrolyte and bubbles, but also removes the influence of prism and achieves higher sensitivity.

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

[0041] The present application proposes an in-situ detection method for measuring the distribution of electrode activity in electrochemical reactions. During the linear scanning voltammetry test using a potential scanning system to drive the electrode, a polarization optical detection device is used to detect the changes in the electrolyte on the electrode participating in the redox reaction process in real time. This process calculates the polarization state change of the electrode surface by collecting the optical signal change caused by the change in the scattering state of the electrode surface. The potential scanning system can obtain the voltage change curve of the entire process, and determine the hydrogen evolution start potential at a certain location by determining the voltage when the polarization state changes. Specifically, a beam of oblique incident polarized light emitted by the light source module penetrates the window and the electrolyte of a certain buffer depth to reach the electrode surface and reflect. The reflected light will scatter with bubbles of various sizes in the solution, and at the same time change the polarization state of the outgoing light. Different bubble sizes have different scattering effects on the incident polarized light. The larger the bubble grows, the more obvious the scattering effect is, resulting in significant changes in the polarization state of the local area. In addition, for a specific material surface, the wavelength and angle of incidence of the incident light will also have a great impact on the polarization state of the light. Therefore, before formally testing a new electrode material, a calibration experiment is required to find the incident light wavelength and incident angle that are most sensitive to the material's polarization state transition.

[0042] like Figure 2 As shown, in some embodiments, in step S1, a calibration experiment is performed on the electrode to be tested, 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 group of input incident light wavelengths and incident angles; during the experiment, a potential scanning system is used to perform a linear scanning voltammetric test on the electrode, and the imaging detection module simultaneously collects images of parallel polarization and vertical polarization; the average polarization degree of the entire image is calculated using a polarization degree formula, and a curve of the average polarization degree of the entire image versus potential is obtained to obtain an average starting potential of the entire image; after measuring the first group, all incident angles to be tested under the first incident light wavelength are tested by changing the incident angle; then, the incident light wavelength is changed, and all incident angles to be tested are continued to be tested to obtain an 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 group 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 to be tested.

[0043] In some embodiments, in step S2, the electrode to be tested 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; during the linear scanning process in step S2, a polarization imaging detection module is used to collect optical images.

[0044] Polarization refers to the phenomenon that the vibration direction of light is asymmetric with the propagation direction of light. The polarization characteristics of the incident light on an object and the reflected light reflected by the object are related to the characteristics of the object itself. In order to describe the change of polarization state, this application introduces the formula of degree of polarization (DoP):

[0045]

[0046] I in the above formula H and I V The intensity values ​​of the linear polarization state components corresponding to the incident linear polarization light at 0 degrees and 90 degrees, respectively. When the polarized light is completely polarized light, the degree of polarization DoP is 1; when the polarized light is not completely polarized light (natural light), the degree of polarization DoP is 0; when the degree of polarization DoP is between 0 and 1, it is represented as partially polarized light. Therefore, this application uses the degree of polarization to quantitatively represent the change in the polarization state.

[0047] The present application uses a polarization imaging detection module to collect optical images, and at the same time uses a potential scanning system to perform a linear scanning voltammetry test on the electrode to obtain a linear scanning voltammetry curve, the horizontal axis of which represents the voltage applied to the electrode. At the same time, the valence state of the active substance in the electrolyte on the electrode changes to generate bubbles, causing changes in the scattering state of light on the electrode surface, which is reflected in the change in the central polarization degree of the optical sensor detection signal. The relationship between the polarization degree signal change and the voltage change obtained above can be used to obtain the size of the starting potential, thereby obtaining the starting potential distribution of the electrode, which provides a new method for in-situ detection of electrode activity distribution.

[0048] The polarization imaging detection method for the distribution of the activity of the hydrogen evolution reaction of the electrode provided by the present application is described in detail below through a specific embodiment. The steps of the method are as follows:

[0049] In the first step, the electrode to be tested is transferred as a working electrode into the potential scanning system module and immersed in the electrolyte, so that it is placed vertically in the electrolyte and facing the lens, and then the module is assembled 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 directed obliquely toward the electrode surface, and the camera with the polarization wheel is placed vertically toward the electrode surface to be tested in the electrolytic cell.

[0051] The third step is to debug the polarization optical detection device and conduct a calibration experiment to determine the incident light wavelength and incident angle that are most sensitive to changes in the degree of polarization on the electrode surface to be tested.

[0052] In the fourth step, a linear scanning voltammetry test is performed on the electrode immersed in the electrolyte by means of a potential scanning system to obtain a linear scanning voltammetry curve. At the same time, the polarization optical detection device collects images of parallel polarization and vertical polarization that change with time.

[0053] Step 5: According to the calculation formula of polarization degree A series of curves showing the change of polarization degree with potential at each position on the parallel polarization and perpendicular polarization images are obtained.

[0054] The sixth step is to set a change reference value, that is, a certain standard deviation of the polarization degree on the platform before the water electrolysis reaction occurs, so as to obtain the polarization degree when the electrode undergoes hydrogen evolution reaction.

[0055] Step 7: According to the curve of polarization degree changing with potential, the starting potential of the position can be found. By repeatedly judging the starting potential of each position, the distribution of hydrogen evolution starting potential on the electrode surface can be obtained.

[0056] See also Figure 3 The embodiment of the present application also provides a polarization imaging detection device for the distribution of the activity of the hydrogen evolution reaction of the electrode, which adopts the polarization imaging detection method for the distribution of the activity of the hydrogen evolution reaction of the electrode for detection. The polarization imaging detection device includes: an incident light module, an optical sensing module, an imaging detection module and a potential scanning system module; wherein the incident light module is used to convert the light emitted by the quasi-monochromatic LED into linear polarized light through a linear polarizer; the optical sensing module is a transparent window, and the electrode to be tested is placed parallel to the window; the change information of the polarization degree is obtained by the change of the scattering state of the light caused by the material change on the surface of the electrode; the imaging detection module is used to alternately collect the parallel polarization and vertical polarization images of the sensing interface; the starting potential of the electrode at the sensing interface is obtained from the synchronous relationship between the change of the polarization degree and the change of the voltage; the potential scanning system module is used to perform a linear scanning voltammetry test on the electrode to be tested immersed in an electrolyte, and study the redox reaction of the electrolyte at the electrode during the linear scanning voltammetry process to change the scattering state of the incident light.

[0057] Figure 4 This is an example of a system that uses a polarization optical detection device to detect the distribution of electrochemical reaction activity in situ during linear sweep voltammetry. 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 out by an optical fiber, passes through the collimating lens 12 and the polarizer 13, and forms linearly polarized light, which is incident on the optical sensing module.

[0058] In some embodiments, the monochromatic LED 11 is an XPE2 LED lamp, 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 out by the optical fiber, passes through the collimating lens 12 and the polarizer 13 to form linear polarized light, and is incident on the optical sensor module. After scattering at the contact interface between the glass window 21 and the working electrode 41, the imaging detection module obtains horizontal and vertical polarized images.

[0060] In some embodiments, the imaging detection module is used to obtain horizontally and vertically polarized images; please continue to refer to Figure 4 The imaging detection module includes an electric filter wheel 31 and a camera 32. The electric filter wheel 31 is equipped with 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 formed into parallel polarization and perpendicular polarization, and the obtained image is thereby subjected to polarization degree calculation.

[0061] Specifically, the electric filter wheel 31 may be a ZWO EFW-mini electric filter wheel, and the camera 32 may be a ZWO ASI183MM-P camera.

[0062] In some embodiments, the polarization imaging detection device also includes: an electrolytic cell 22 and a three-electrode module arranged in 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 so 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 the electrochemical reaction. The change in the valence state of the electrolyte causes a hydrogen evolution reaction to occur on the electrode surface. The generated bubbles cause a change in the scattering state of light and thus cause a change in the degree of polarization. The potential scanning system 44 uses a computer display to display the linear scanning voltammetric curve obtained by the potential scanning system and a series of parallel polarization and vertical polarization images captured by the camera, such as Figure 4 As shown, the computer 45 receives the polarization image and the voltammetric curve.

[0065] Figure 5 This is an example of image acquisition by the imaging detection module during the water electrolysis reaction process. Figure 5 The order of collecting images for the imaging detection module. The electrode immersed in the electrolyte is subjected to a linear scanning voltammetric test by means of a potential scanning system, while the imaging detection module alternately collects parallel polarization and perpendicular polarization images that change with time.

[0066] Figure 6 This is an example of image processing performed by the imaging detection module during the water electrolysis reaction. Figure 6(a) is to use the polarization degree formula Adjacent parallel polarization and vertical polarization images are processed. Figure 6 (b) is the image obtained by subtracting the polarization degree image obtained by subsequent processing from the polarization degree image obtained in the first group and calculating the absolute value. Figure 6 (c) is a curve showing the change of polarization degree at a point randomly selected on the image as a function of potential. It can be seen that during the reaction, the polarization degree at each point will first experience a platform before a step, and the starting potential of the step (point A) is defined as the hydrogen evolution starting potential.

[0067] Figure 7 This is an example of the starting potential distribution diagram of hydrogen evolution in water electrolysis obtained with different copper electrode materials in 1 mol / L KOH solution at a potential scanning rate of 1 mV / s. Figure 7 (a) is the copper plate starting potential distribution diagram of catalysts loaded with different ratios of RuO2 and Co3O4 (the last row is without catalyst loading). Figure 7 In (a), the Ru:Co raw material 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 catalysts with different ratios of RuO2 and Co3O4 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 distribution of hydrogen evolution reaction in water electrolysis on the copper mesh also confirms the reliability and accuracy of the device for detecting the activity distribution of electrode materials.

[0068] Based on the above technical scheme, the embodiment of the present application provides a polarization imaging detection method and device for the distribution of electrode hydrogen evolution reaction activity, and the method includes the following steps: first, a calibration experiment is performed on the electrode to be tested to determine the optimal incident light wavelength and incident angle for detecting the polarization degree of the electrode to be tested; then, the electrode to be tested is used as a working electrode in a potential scanning system, and a linear scanning voltammetry test is performed on the working electrode immersed in an electrolyte using the potential scanning system to obtain a linear scanning voltammetry curve; during the linear scanning process, an optical image is collected using a polarization imaging detection module at the same time; next, a pixel point on the image is randomly selected, and according to the calculation formula of the polarization degree, a curve of the polarization degree changing with the potential at the position can be obtained, thereby determining the starting potential of the point; finally, all positions on the optical image are traversed to obtain the distribution of the hydrogen evolution starting potential of the electrode material, that is, the distribution of the electrode hydrogen evolution reaction activity.

[0069] The polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity provided by the present application uses a potential scanning system to drive the electrode to perform a linear scanning voltammetric test, and uses a polarization optical detection device to detect in real time the changes in the electrolyte on the electrode participating in the redox reaction process. This process calculates the change in the polarization state of the electrode surface by collecting the change in the optical signal caused by the change in the scattering state of the electrode surface. The potential scanning system can obtain the voltage change curve of the entire process, and determine the hydrogen evolution starting potential at a certain location by determining the voltage when the polarization state changes. This method is simple to operate, but can obtain in-situ, real-time, and effective electrode activity distribution, providing a detection tool for electrode modification.

[0070] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present application. Any person skilled in the art can make their own changes and modifications without departing from the spirit and scope of the present application, so the scope of protection of the present application shall be based on the scope defined in the claims.

Claims

1. A polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity, characterized in that: The following steps are involved: Conduct a calibration experiment on the electrode to be tested to determine the optimal incident light wavelength and incident angle for polarization detection of the electrode to be tested; The electrode to be tested is used as the working electrode, and a linear sweep voltammetry test is performed on the working electrode immersed in the electrolyte to obtain a linear sweep voltammetry curve; During the linear scanning process, the optical image is collected simultaneously; Randomly select a pixel point on the image, and according to the calculation formula of polarization degree, we can get the curve of polarization degree changing with potential at that position, so as to determine the starting potential of that point; By traversing all positions on the optical image, the distribution of the hydrogen evolution starting potential of the electrode material, that is, the distribution of the electrode hydrogen evolution reaction activity, is obtained.

2. The polarization imaging detection method for the electrode hydrogen evolution reaction activity distribution according to claim 1, characterized in that: Calibration experiments are performed on the electrodes to be tested, including: First, a series of different incident light wavelengths and different incident angles are set for the electrode material; Perform polarization imaging experiments on the first group of input incident light wavelengths and incident angles; During the experiment, the potential scanning system was used to perform linear scanning voltammetry tests on the electrodes, while the imaging detection module collected images of parallel polarization and perpendicular polarization; The average polarization degree of the whole image is calculated using the polarization degree formula, and the curve of the average polarization degree of the whole image changing with the potential is obtained, and the average starting potential of the whole image is obtained; After the first group is measured, all the incident angles to be measured under the first incident light wavelength are tested by changing the incident angle; then the incident light wavelength is changed, and all the incident angles to be measured are continued to be tested to obtain the average starting potential of the whole graph; After all parameter tests are completed, the average starting potentials of the entire graph obtained under different parameters are compared, and the group 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 to be tested.

3. The polarization imaging detection method for the electrode hydrogen evolution reaction activity distribution according to claim 1, characterized in that: The calculation formula of the polarization degree is: Among them, I H and I V They correspond to the intensity values ​​of the linear polarization state components when they are 0 degrees and 90 degrees to the incident linear polarized light respectively; when the polarized light is completely polarized light, the degree of polarization DoP is 1; when the polarized light is not completely polarized light, the degree of polarization DoP is 0; when the degree of polarization DoP is between 0 and 1, it indicates partially polarized light.

4. A polarization imaging detection device for electrode hydrogen evolution reaction activity distribution, using the polarization imaging detection method for electrode hydrogen evolution reaction activity distribution according to any one of claims 1 to 3 for detection, characterized in that: The polarization imaging detection device comprises: Incident light module, optical sensing module, imaging detection module and potential scanning system module; wherein, The incident light module is used to convert the light emitted by the quasi-monochromatic LED into linear polarized light through a linear polarizer; The optical sensing module is a transparent window, and the electrode to be tested is placed parallel to the window; the change in polarization degree is obtained by changing the scattering state of light caused by the material change on the electrode surface; The imaging detection module is used to alternately collect parallel polarization and vertical polarization images of the sensing interface; the starting potential of the electrode at the sensing interface is obtained from the curve of the change of polarization degree with potential; The potential scanning system module is used to perform a linear scanning voltammetry test on the electrode to be tested which is immersed in the electrolyte, and to study the change of the incident light scattering state caused by the redox reaction of the electrolyte at the electrode during the linear scanning voltammetry process.

5. The polarization imaging detection device for the distribution of electrode hydrogen evolution reaction activity according to claim 4, characterized in that: 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 out by the optical fiber, passes through the collimating lens and the polarizer, and forms linearly polarized light, which is incident on the optical sensor module.

6. The polarization imaging detection device for the distribution of electrode hydrogen evolution reaction activity according to claim 5, characterized in that: The monochromatic LED is an XPE2 LED lamp, the collimating lens is a GCL-010650 collimating lens, and the polarizer is a GCL-050003 linear polarizer.

7. The polarization imaging detection device for the distribution of electrode hydrogen evolution reaction activity according to claim 4, characterized in that: 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. The electric filter wheel is equipped with 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 form parallel polarization and perpendicular polarization respectively, so that the polarization degree of the obtained image can be calculated.

8. The polarization imaging detection device for the distribution of electrode hydrogen evolution reaction activity according to claim 4, characterized in that: Also includes: An electrolytic cell and a three-electrode module disposed in 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 so that the electrolyte immerses the working electrode, the counter electrode and the reference electrode.

9. The polarization imaging detection method for the distribution of electrode hydrogen evolution reaction activity according to claim 8, 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.

10. The polarization imaging detection device for electrode hydrogen evolution reaction activity distribution according to claim 4, 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 to occur on the electrode surface. The generated bubbles cause a change in the scattering state of light and thus cause 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 polarization and vertical polarization images captured by a camera.

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