Method for detecting hydrogen evolution performance of electrode by using atomic force microscope

Abstract

The invention discloses a method for detecting hydrogen evolution performance of an electrode by using an atomic force microscope. Washing the foamed nickel to obtain pretreated foamed nickel; and with the pretreated foamed nickel as a cathode, graphite as an anode and a silver plating electroplating solution as an electrolyte, electroplating by adopting a constant voltage method, so that the foamed nickel is converted into Ni-Ag / NF. An electrode prepared by an electro-deposition method is placed under an atomic force microscope, a single molecule force spectrum method of the atomic force microscope is utilized to enable a probe of the atomic force microscope to be in continuous contact with the electrode to generate a force-distance curve, the adhesion energy of a deposited object is calculated through the force-distance curve, and the larger the adhesion energy is, the better the hydrogen evolution performance of the electrode is. For Ni-Ag / NF electrodes prepared under different conditions, the result obtained by detecting the hydrogen evolution performance by using an atomic force microscope is consistent with the result obtained by detecting the overpotential of the electrode by using an electrochemical workstation. A new evaluation index is developed for hydrogen evolution performance detection of the electrode, and the application range of the atomic force microscope is widened.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen evolution performance detection, and particularly relates to a method for detecting hydrogen evolution performance of an electrode by using an atomic force microscope. BACKGROUND

[0002] With the increasingly serious energy crisis and environmental problems, the development of clean and renewable alternative energy has become an urgent need, and water electrolysis hydrogen production has become one of the core technologies due to its pure product and renewable raw materials. However, the high overpotential of hydrogen evolution reaction (HER) and the problem of catalyst deactivation restrict its industrial application. Noble metals such as Ir, Ru and their oxides are the most effective OER electrocatalysts, and Pt and Pt-based alloys show the highest HER activity. Non-noble metal catalysts have become the focus of research to replace noble metals (Pt) due to cost advantages. Non-noble metal hydrogen evolution catalysts mainly include phosphides, chalcogenides and alloys based on transition metals such as Mo, W, Fe, Co and Ni. Since the content of Mo and W in the earth's crust (about 0.00011%) is much lower than that of Fe, Co and Ni (6.8%, 0.003% and 0.0089% respectively), it is more conducive to the large-scale industrialization of electrocatalytic hydrogen evolution technology to develop low-cost Fe, Co and Ni-based electrocatalytic hydrogen evolution catalysts.

[0003] In industrial alkaline electrolyzers, Ni-based electrodes are usually used as cathodes to produce hydrogen because of its low cost and corrosion resistance at high pH, but the electrocatalytic activity of nickel is usually not high, and more importantly, the catalyst is easy to deactivation when performing continuous alkaline hydrogen evolution electrolysis. While nickel foam is widely used in HER and other fields due to its excellent electrical conductivity and unique three-dimensional (3D) porous structure, researchers have been working to develop nickel-based alloys to improve their activity and stability. The rational design of Ni3S2nanosheets-Ag nanorods on Ni foam with improved hydrogen adsorption sites for the hydrogen evolution reaction. Sustainable (Energy & Fuels 2021, 5 (13), 3428-3435, Article. DOI: 10.1039 / d1se00702e.) reported that on Ni3S2-Ag / NF in nickel foam, the strong interaction between Ag and Ni3S2promotes the Volmer and Heyrovsky processes, thereby providing excellent activity in alkaline electrolytes. In terms of alkaline HER, microscopic images of water, H* and OH* adsorption on metal surfaces under ultra-high vacuum or electrocatalytic conditions are essential to estimate their activity. From both theoretical and experimental perspectives, hydrogen adsorption free energy (ΔGH*) is the most important factor in describing the HER / HOR activity of the electrode in acidic solutions. At the same time, how to optimize the interface catalytic activity and stability is still a key challenge in electrocatalytic processes, and the interface interaction between the catalyst and the reaction intermediates (such as H*) directly affects the reaction kinetics, while the adsorption-desorption behavior of hydrogen (H2) on the electrode surface is one of the core factors that determine the efficiency of hydrogen evolution.

[0004] Although the amount of hydrogen evolution can be used as one of the indicators to evaluate the performance of the electrode, the service life of the electrode and the like are also one of the indicators for evaluating the hydrogen evolution efficiency. Whether the electrode can be repeatedly used or the service life and the like are properties that cannot be detected by hydrogen evolution once. At present, the main indicator for directly evaluating the hydrogen evolution performance of the electrode is to detect the overpotential of the electrode by an electrochemical workstation, and the evaluation means is relatively single. Therefore, it is necessary to develop a new detection method for evaluating the hydrogen evolution performance of the electrode, which provides an important basis for in-depth analysis of the hydrogen evolution capacity of the electrode. SUMMARY

[0005] In view of the prior art, the present application aims to provide a method for detecting electrode hydrogen evolution performance by using an atomic force microscope. The present application uses an atomic force microscope (AFM) to detect the electrode Ni-Ag / NF prepared by electrodeposition method, obtains a force-distance curve, calculates the adhesion energy of the deposited substance through the curve, and establishes the relationship between the adhesion energy and the electrode hydrogen evolution performance. The present application finds that the greater the adhesion energy of the deposited substance, the better the hydrogen evolution performance of the electrode. For the Ni-Ag / NF electrodes prepared under different conditions, the results obtained by using the atomic force microscope to detect the hydrogen evolution performance are consistent with the results obtained by using an electrochemical workstation to detect the overpotential of the electrode. The present application opens up a new evaluation index for the detection of electrode hydrogen evolution performance, and broadens the application of the atomic force microscope.

[0006] To achieve the above object, the present application adopts the following technical solutions: In a first aspect, the present application provides an application of an atomic force microscope in detecting electrode hydrogen evolution performance, wherein the electrode is an electrode prepared by electrodeposition method, and the material of the electrode is Ni-Ag / NF.

[0007] Preferably, the Ni-Ag / NF is prepared by the following method: (1) washing foam nickel to obtain pretreated foam nickel; (2) using the pretreated foam nickel as a cathode, graphite as an anode, and a silver plating electrolyte as an electrolyte, performing electroplating by using a constant voltage method, so that the foam nickel is converted into Ni-Ag / NF.

[0008] Preferably, in step (1), the pretreatment is: first, ultrasonic degreasing the foam nickel in ethanol, then washing with deionized water, then immersing in a hydrochloric acid solution, then ultrasonic cleaning with deionized water, and finally drying to obtain the pretreated foam nickel.

[0009] Preferably, in step (2), the silver plating electrolyte is obtained by mixing a silver nitrate solution and an ammonia buffer solution; the preparation method of the ammonia buffer solution is: dissolving NH4Cl in ultrapure water, then adding concentrated ammonia water and ultrapure water, and then mixing uniformly to obtain; the concentration of the silver nitrate solution is 1-5 mM.

[0010] Preferably, the concentration of NH4Cl in the ammonia buffer solution is 0.1 M, and the concentration of KNO3 is 0.1 M; the volume of the concentrated ammonia water accounts for 35% of the volume of the ammonia buffer solution; the volume ratio of the ammonia buffer solution to the silver nitrate solution is 1:7.

[0011] Preferably, in step (2), the voltage of the electroplating is 1-5 V, and the time is 20-40 min.

[0012] In a second aspect, the present application provides a method for detecting electrode hydrogen evolution performance by using an atomic force microscope, characterized in that the method is: The electrode prepared by the electrodeposition method is placed under an atomic force microscope, and a force-distance curve is generated by continuously contacting the probe of the atomic force microscope with the electrode, and the adhesion energy of the deposited material is calculated through the force-distance curve, and the larger the adhesion energy is, the better the hydrogen evolution performance of the electrode is.

[0013] Preferably, the contact is that the probe of the atomic force microscope continuously contacts at least 10 points selected on the electrode for at least 50 times.

[0014] Preferably, the material of the electrode is Ni-Ag / NF, and the Ni-Ag / NF is prepared by the following method: (1) washing the foamed nickel to obtain pretreated foamed nickel; (2) using the pretreated foamed nickel as a cathode, using graphite as an anode, using a silver plating electrolyte as an electrolyte, and using a constant voltage method for electroplating to convert the foamed nickel into Ni-Ag / NF.

[0015] Preferably, the calculation formula of the adhesion energy is ; Wherein, F(d): the interaction force between the probe and the electrode, which changes with the distance d; d1 is the initial distance of the contact between the probe and the electrode; and d2 is the distance at which the probe completely separates from the electrode.

[0016] The present application has the following advantages: (1) The present application uses the atomic force microscope to detect the electrode Ni-Ag / NF prepared by the electrodeposition method, obtains a force-distance curve, calculates the adhesion energy of the deposited material through the curve, and establishes the relationship between the adhesion energy of the deposited material and the hydrogen evolution performance of the electrode. The present application researches and finds that the larger the adhesion energy of the deposited material is, the better the hydrogen evolution performance of the electrode is. For the Ni-Ag / NF electrodes prepared under different conditions, the detection results of the hydrogen evolution performance by the atomic force microscope are consistent with the results obtained by the overpotential detection of the electrode by the electrochemical workstation. The present application opens up a new evaluation index for the detection of the hydrogen evolution performance of the electrode, and widens the application of the atomic force microscope.

[0017] (2) The present application combines the AFM adhesion energy data with the electrochemical test, establishes the correlation of "adhesion uniformity - surface interfacial force spectrum - catalytic performance", and provides experimental basis for solving the deactivation problem of the Ni-based electrode in an alkaline electrolytic cell. The AFM technology not only serves as a characterization tool in the process, but also becomes a bridge connecting the atomic scale interface behavior and the macroscopic catalytic performance, and provides a new idea for the interface engineering design of non-noble metal catalysts.

[0018] (3) The detection method is simple, only one detection device of an atomic force microscope is needed, so that the hydrogen evolution performance of the electrode is detected. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 : Schematic diagram of detecting the electrode (sample) by using AFM; Figure 2 : (a) is the surface morphology of 1mM-3V-30min sample, (b) is the interface morphology of 1mM-3V-30min sample, (c) is the surface morphology of 3mM-3V-30min sample, (d) is the interface morphology of 3mM-3V-30min sample, (e) is the surface morphology of 5mM-3V-30min sample, and (f) is the interface morphology of 5mM-3V-30min sample; Figure 3 : (a) is the statistical distribution diagram of the adhesion force between Ni and Ag of 1mM-3V-30min sample, (b) is the statistical distribution diagram of the adhesion force of the plating surface of 1mM-3V-30min sample, (c) is the statistical distribution diagram of the adhesion force between Ni and Ag of 3mM-3V-30min sample, (d) is the statistical distribution diagram of the adhesion force of the plating surface of 3mM-3V-30min sample, (e) is the statistical distribution diagram of the adhesion force between Ni and Ag of 5mM-3V-30min sample, and (f) is the statistical distribution diagram of the adhesion force of the plating surface of 5mM-3V-30min sample; Figure 4 : (a) is the adhesion force curve of 1mM-3V-30min sample; (b) is the adhesion force curve of 1mM-1V-30min sample; (c) is the adhesion force curve of 1mM-5V-30min sample; (d) is the adhesion force curve of 3mM-3V-30min sample; (e) is the adhesion force curve of 5mM-3V-30min sample; (f) is the adhesion force curve of 1mM-3V-40min sample; (g) is the adhesion force curve of 1mM-3V-20min sample; and (h) is a schematic diagram of integrating the adhesion force curve to obtain the adhesion energy; Figure 5 : (a) is the SEM image of 1mM-3V-30min sample under 100um, (b) is the SEM image of 1mM-3V-30min sample under 500um, (c) is the SEM image of 3mM-3V-30min sample under 100um, (d) is the SEM image of 3mM-3V-30min sample under 500um, (e) is the SEM image of 5mM-3V-30min sample under 100um, and (f) is the SEM image of 5mM-3V-30min sample under 500um; Figure 6: (a) is the surface topography of the 1 mM-3 V-30 min sample, (b) is the interface topography of the 1 mM-3 V-30 min sample, (c) is the surface topography of the 1 mM-1 V-30 min sample, (d) is the interface topography of the 1 mM-1 V-30 min sample (e) is the surface topography of the 1 mM-5 V-30 min sample, (f) is the interface topography of the 1 mM-5 V-30 min sample; Figure 7 : (a) is the statistical distribution of the Ni to Ag interface adhesion force of the 1 mM-3 V-30 min sample, (b) is the statistical distribution of the plated surface adhesion force of the 1 mM-3 V-30 min sample, (c) is the statistical distribution of the Ni to Ag interface adhesion force of the 1 mM-1 V-30 min sample, (d) is the statistical distribution of the plated surface adhesion force of the 1 mM-1 V-30 min sample, (e) is the statistical distribution of the Ni to Ag interface adhesion force of the 1 mM-5 V-30 min sample, (f) is the statistical distribution of the plated surface adhesion force of the 1 mM-5 V-30 min sample; Figure 8 : (a) is the SEM image of the 1 mM-3 V-30 min sample at 100 um, (b) is the SEM image of the 1 mM-3 V-30 min sample at 500 um, (c) is the SEM image of the 1 mM-1 V-30 min sample at 100 um, (d) is the SEM image of the 1 mM-1 V-30 min sample at 500 um, (e) is the SEM image of the 1 mM-5 V-30 min sample at 100 um, (f) is the SEM image of the 1 mM-5 V-30 min sample at 500 um; Figure 9 : (a) is the surface topography of the 1 mM-3 V-30 min sample, (b) is the interface topography of the 1 mM-3 V-30 min sample, (c) is the surface topography of the 1 mM-3 V-40 min sample, (d) is the interface topography of the 1 mM-3 V-40 min sample (e) is the surface topography of the 1 mM-3 V-20 min sample, (f) is the interface topography of the 1 mM-3 V-20 min sample; Figure 10 : (a) is the statistical distribution of the Ni to Ag interface adhesion force of the 1 mM-3 V-30 min sample, (b) is the statistical distribution of the plated surface adhesion force of the 1 mM-3 V-30 min sample, (c) is the statistical distribution of the Ni to Ag interface adhesion force of the 1 mM-3 V-20 min sample, (d) is the statistical distribution of the plated surface adhesion force of the 1 mM-3 V-20 min sample, (e) is the statistical distribution of the Ni to Ag interface adhesion force of the 1 mM-3 V-40 min sample, (f) is the statistical distribution of the plated surface adhesion force of the 1 mM-3 V-40 min sample; Figure 11: (a) SEM image of 1 mM-3 V-30 min sample at 100 um, (b) SEM image of 1 mM-3 V-30 min sample at 500 um, (c) SEM image of 1 mM-3 V-20 min sample at 100 um, (d) SEM image of 1 mM-3 V-20 min sample at 500 um, (e) SEM image of 1 mM-3 V-40 min sample at 100 um, (f) SEM image of 1 mM-3 V-40 min sample at 500 um; Figure 12 : (a) lsv curves of different electrolyte concentration samples; (b) tafe plots of different electrolyte concentration samples; (c) Cdl curves of Pt-C samples at different scan rates, (d) Cdl curves of 1 mM-3 V-30 min samples at different scan rates, (e) Cdl curves of 3 mM-3 V-30 min samples at different scan rates, (f) Cdl curves of 5 mM-3 V-30 min samples at different scan rates; (g) ECSA of different electrolyte concentration samples; h. overpotential size of different samples; dl dl dl dl Figure 13 : XPS chart of 1 mM-3 V-30 min sample, (a) is Ag (silver) element characteristic peak; (b) is Ni (nickel) element characteristic peak; (c) is O (oxygen) element characteristic peak; (d) is element analysis main spectrum chart; Figure 14 : XRD chart of 1 mM-3 V-30 min sample; Figure 15 : Stability curve chart of 1 mM-3 V-30 min sample; Figure 16 : Figure 16 : (a) lsv curves of different electrolyte concentration samples; (b) tafe plots of different electrolyte concentration samples; (c) Cdl curves of Pt-C samples at different scan rates, (d) Cdl curves of 1 mM-3 V-30 min samples at different scan rates, (e) Cdl curves of 1 mM-1 V-30 min samples at different scan rates, (f) Cdl curves of 1 mM-5 V-30 min samples at different scan rates; (g) ECSA of different electrolyte concentration samples; h. overpotential size of different samples; Figure 17 : (a) lsv curves of different electrolyte concentration samples; (b) tafe plots of different electrolyte concentration samples; (c) Cdl curves of Pt-C samples at different scan rates, (d) Cdl curves of 1 mM-3 V-30 min samples at different scan rates, (e) Cdl curves of 1 mM-1 V-30 min samples at different scan rates, (f) Cdl curves of 1 mM-5 V-30 min samples at different scan rates; (g) ECSA of different electrolyte concentration samples; h. overpotential size of different samples; dl ​​​​Curves, (d) C of 1 mM-3 V-30 min samples at different scanning speeds dl Curves, (e) C of 1 mM-3 V-20 min samples at different scanning speeds dl Curves, (f) C of 1 mM-3 V-40 min samples at different scanning speeds dl Curves; (g) ECSA of samples with different electrolyte concentrations; (h) overpotential of different samples. DETAILED DESCRIPTION

[0020] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0021] As introduced in the background section, although the amount of hydrogen evolution can be used as one of the indicators of hydrogen evolution efficiency to evaluate the performance of the electrode, the service life of the electrode and the like are also one of the indicators for investigating the hydrogen evolution efficiency. The performance of whether the electrode can be repeatedly used or the service life and the like cannot be detected by one-time hydrogen evolution. At present, the main indicator for directly evaluating the hydrogen evolution performance of the electrode is to detect the overpotential of the electrode by an electrochemical workstation, and the evaluation means is relatively single.

[0022] Based on this, the purpose of the present application is to provide the application of atomic force microscopy in detecting the hydrogen evolution performance of the electrode. The present application uses the interaction force at the single molecular level provided by the AFM to measure the electrode, and obtains the force-distance curve (F-E curve) through the contact between the probe and the electrode. That is, the single molecular force spectrum (SMFS) technology based on the atomic force microscope (AFM) only studies the interaction force of the electrode without generating molecular bridges, and the core principle focuses on directly detecting the non-covalent interaction (such as van der Waals force, hydrogen bond, electrostatic interaction) between the molecules of the electrode material by the AFM probe.

[0023] The traditional SMFS relies on the "molecular bridge" to realize the transmission of force, and the force spectrum technology without the molecular bridge directly measures the interaction force between the probe and the molecules on the surface of the electrode through the in-situ interaction of the probe. The specific principle is as follows: The binding force of both is measured through the probe approach-avoidance process (without constructing a molecular bridge, but through the direct action of the probe-electrode surface molecules). The in-situ interaction refers to directly scanning the electrode surface by using an unmodified AFM probe (such as a silicon probe, a silicon nitride probe), obtaining the intrinsic interaction force between molecules through a force-distance curve, and electrode surface force mapping: the spatial distribution of intermolecular interaction (such as the difference in hydrogen bond strength in different regions) is drawn by scanning the force change of the probe on the electrode surface. The AFM single molecule force spectrum technology without molecular bridge bypasses the complex molecular bridge construction process, and directly obtains the information of the intermolecular interaction force through the in-situ detection of the probe. Its core advantage lies in simple operation and suitability for statistical analysis of surface force. Based on the above principle, the present application uses the single molecule force spectrum (SMFS) of the atomic force microscope (AFM) as a new characterization technology, and reveals the adhesion force regulation mechanism of the NiAg alloy electrode. The single molecule force spectrum (SMFS) based on the atomic force microscope (AFM) becomes a general platform for studying intermolecular and intramolecular interactions due to its extremely high force sensitivity, Ag doping optimizes the electronic structure of Ni, reduces the interface adhesion force dispersion, and promotes H2 desorption. The present application combines the AFM adhesion energy data and the electrochemical test, establishes the correlation of “adhesion force uniformity - surface interface force spectrum - catalytic performance”, and provides an experimental basis for solving the deactivation problem of the Ni-based electrode in the alkaline electrolytic cell. In this process, the AFM technology not only serves as a characterization tool, but also becomes a bridge connecting the atomic scale interface behavior and the macroscopic catalytic performance, and provides a new idea for the interface engineering design of non-noble metal catalysts.

[0024] In order for those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in conjunction with specific embodiments.

[0025] Description: The atomic force microscope used in the present application is of the following type: JPK Forcerobot300, brand: Germany Bruker.

[0026] The test materials used in the embodiments of the present application are all conventional test materials in the art and can be purchased through commercial channels.

[0027] Example 1: Preparation of Ni-Ag / NF (1) First, the nickel foam is ultrasonically degreased in ethanol for 15 min, washed with deionized water, then immersed in a 3.0M hydrochloric acid solution to remove the oxide film, then ultrasonically washed with deionized water for 15 min, and finally dried in a vacuum drying oven at 50℃ for 30 min to obtain pretreated nickel foam.

[0028] (2) Take NH4Cl into a beaker, add 20 mL of ultrapure water to dissolve, then add 35 mL of concentrated ammonia water (ammonia water has a strong irritating odor, operate in a fume hood), dilute to 100 mL with ultrapure water to obtain an ammonia buffer solution. The purpose of adding the buffer solution is to control the pH of the solution and ensure stable plating effect. Mix 1 mM, 3 mM or 5 mM AgNO3 solution with the ammonia buffer solution at a volume ratio of 7:1 to obtain a silver plating solution. This ratio can basically ensure that the Ag + forms a stable complex, allowing the plating process to proceed stably.

[0029] The pretreated nickel foam is fixed by a platinum sheet electrode clamp as the cathode for plating, and a graphite electrode is used as the anode. The silver plating solution is used as the electrolyte. The two electrodes are assembled in a cylindrical electrolytic cell containing 200 mL of electrolyte. The graphite electrode is connected to the positive pole of the power supply, and the cathode is connected to the negative pole of the power supply. A constant voltage method is used to perform plating in the cylindrical electrolytic cell using a direct current power supply. The plating voltage is 1 V, 3 V or 5 V, and the time is 20, 30 or 40 min.

[0030] In this example, seven Ni-Ag / NF were prepared under different conditions, specifically: (1) AgNO3 solution concentration: 1 mM, 3 mM or 5 mM; plating voltage: 3 V; plating time: 30 min.

[0031] (2) Plating voltage: 1 V, 3 V or 5 V; AgNO3 solution concentration: 3 mM; plating time: 30 min.

[0032] (3) Plating time: 20, 30 or 40 min; AgNO3 solution concentration: 3 mM; plating voltage: 3 V.

[0033] Among them, (1), (2) and (3) all have 3 mM-3 V-30 min, which is an electrode, and the related data are repeatedly used and do not need to be tested separately.

[0034] Example 2: Detection of hydrogen evolution performance of the electrode using AFM and single molecule force spectroscopy 1. Detection The seven Ni-Ag / NF obtained in Example 1 were tested using single molecule force spectroscopy to obtain F-E curves and topography maps. The specific operation is as follows: The Ni-Ag / NF was encapsulated with cold epoxy resin (HJER 1000, Hongjin Detection Equipment (Guangzhou) Co., Ltd.). After the epoxy resin was cured, the epoxy resin (electrode) was cut open to obtain the electrode interface, and the remaining part except the electrode interface was polished to expose the Ni-Ag / NF. For example, Figure 1The AFM probe was contacted with the electrode interface, exposed Ni-Ag / NF, at least 10 different positions, at least 50 times for each site, with a spring constant of about 30 pN / nm for the cantilever beam, and a stretching speed of 2.0 μm / s. The AFM (Park XE-100) obtained F -E curve and topography map in force measurement mode. To ensure the accuracy of the statistical results, more than 100 F-E curves were used for data analysis under each condition.

[0035] 2. Analysis (1) Different concentrations of AgNO3 solution The three Ni-Ag / NF samples obtained in Example 1 with different concentrations of AgNO3 solution, same plating voltage and plating time are respectively recorded as 1mM-3V-30min, 3mM-3V-30min and 5mM-3V-30min.

[0036] Figure 2 This set of AFM (atomic force microscope) images shows the surface and interface topography of the samples after applying a voltage of 3V for 30min under different concentrations. Figure 2 (a) and Figure 2 (b) are 1mM-3V-30min, the surface shows a certain unevenness. From the color distribution, it can be seen that there are height differences on the surface. The color scale shows Figure 2 (a) The height range is 421.57nm - 862.54nm, indicating that the Ag layer on the surface of the sample is relatively uniform. Figure 2 (b) The height range is 293.1nm- 1213nm, indicating that the surface has a certain fluctuation, indicating that Ag and Ni coexist at the interface of the sample. Figure 2 (c) and Figure 2 (d) correspond to 3mM-3V-30min, compared with 1mM-3V-30min, the surface structure is more complex. The height ranges are - 471nm -2231nm and - 421.7nm - 2303.3nm, Figure 2 (e) and Figure 2(f) The surface morphology is further changed after 5 mM-3V-30 min. The height ranges are -546.4 nm-1.878 pm and 65.5 nm-216.7 nm, respectively. With the increase of the sample concentration from 1 mM to 5 mM, the roughness and height range of the surface generally show an increasing trend, and the surface microstructure becomes more complex from relatively simple. This indicates that the concentration is an important factor affecting the surface and interface morphology of the sample. At low concentration (1 mM), molecules can occupy adsorption sites in an orderly manner, while at high concentration, the interaction between molecules is enhanced, and the adsorption process becomes more complex, and multi-layer adsorption or molecular aggregation adsorption may occur. In view of this point, the concentration of 1 mM is more suitable.

[0037] As shown in Figure 3 , Figure 3 (a), Figure 3 (c), Figure 3 (e) is the distribution histogram of the interfacial adhesion between Ni and Ag at different concentrations. With the increase of the concentration of AgNO3 solution from 1 mM to 5 mM, the distribution range and peak position of the interfacial adhesion between Ni and Ag change. When the concentration of AgNO3 solution is 1 mM, the adhesion force is relatively concentrated between 2.8-3.2 nN; when the concentration is 3 mM, the distribution range is widened, and the proportion of adhesion force with different peak values changes; when the concentration is 5 mM, the distribution is more discrete than before, indicating that the concentration changes the strength and nature of the interfacial interaction. The adhesion force distribution shows a single peak shape, and the peak is at a specific force value, indicating that the interaction between atoms on the electroplated surface is relatively single at a concentration of 1 mM, mainly combined in one or several similar ways, forming a relatively concentrated adhesion performance. Figure 3 (b), Figure 3 (d), Figure 3 (f) is the adhesion force of the electroplated surface at different concentrations. The adhesion force distribution of the electroplated surface also changes with the concentration. At 1 mM, the adhesion force has a specific distribution and peak; at 3 mM, the distribution form changes, and the peak position and height are different; at 5 mM, the distribution is discrete, indicating that the concentration has a significant effect on the properties of the electroplated layer, changes the microstructure and composition of the electroplated layer, and further affects the adhesion. The adhesion force distribution is the most concentrated at 1 mM, the ion concentration is low, the deposition is slow, and the structure of the plated layer is more dense, so the concentration of 1 mM is the best for the plating solution.

[0038] Figure 4(a) The adhesion energy curve corresponding to Ag and Ni has a specific shape, reflecting the interface interaction of the electrode (1 mM-3V-30min) under the conditions of 1 mM concentration, 3V voltage, and 30min treatment. At this time, the trend and shape of the curve show that the interatomic binding force and interaction mode are relatively stable. By integrating the curve and taking the average value, the adhesion energy of the Ag surface under 1 mM concentration is 7.01765×10 -15 J, and the adhesion energy of the Ni interface is 7.00175×10 -15 J. Figure 4 (d) The adhesion energy of the Ag surface under 3 mM-3V-30min is 7.3935×10 -15 J, and the adhesion energy of the Ni interface is 7.3895×10 -15 J, and the increase in concentration makes the interatomic interaction more complex, resulting in a change in adhesion energy. Figure 4 (e) The adhesion energy of the Ag surface under 5 mM-3V-30min is 7.4041×10 -15 J, and the adhesion energy of the Ni interface is 7.4024×10 -15 J, and the increase in concentration makes the interatomic interaction more complex, resulting in a change in adhesion energy.

[0039] According to the adhesion energy calculation formula: .

[0040] The adhesion energy of the Ag surface under 1 mM-3V-30min, 3 mM-3V-30min, and 5 mM-3V-30min is 7.01765×10 -15 J, 7.3935×10 -15 J, and 7.4041×10 -15 J, respectively. This indicates that the AgNO3 solution concentration is 1 mM, and the electrode obtained has the best hydrogen evolution performance.

[0041] 2) Figure 5 The electron microscope images of Ni-Ag / NF obtained under different AgNO3 solution concentrations. From Figure 5 (a), Figure 5 (c), Figure 5(e) Low magnification (100um) images show that all samples present porous structure under different conditions. This structure increases the specific surface area of the material, which is beneficial to increase the active site exposure, improve the reaction performance, and more active sites can promote the adsorption of reactants and the progress of the reaction. Figure 5 (b), Figure 5 (d), Figure 5 (f) High magnification (500um) images show that there are differences in the surface of the porous framework. The surface of the 1mM - 3V - 30min framework is relatively flat; the surface of the 3mM - 3V - 30min and 5mM - 3V - 30min frameworks has more fine protrusions or attachments, which may be the deposition of substances generated under different concentrations, which can affect the surface properties of the material, such as wettability, conductivity, etc.

[0042] 3) The overpotential of the three Ni-Ag / NF samples was detected by an electrochemical workstation, including linear sweep voltammetry (LSV) curve and electrochemical impedance spectroscopy (EIS) test. Before the two tests, cyclic voltammetry (CV) was used to activate the NF-Ag electrode material at a scan rate of 120 mV / s for 15 cycles, so as to obtain relatively stable data in the subsequent test and ensure that the prepared electrode material has certain repeatability.

[0043] The overpotential of 1mM-3V-30min, 3mM-3V-30min and 5mM-3V-30min is 181, 190 and 220 V, respectively, indicating that the hydrogen evolution performance of the 1mM-3V-30min sample is the best. This is consistent with the AFM detection results.

[0044] (2) Different plating voltages The three Ni-Ag / NF samples obtained in Example 1 with different plating voltages, the same AgNO3 solution concentration and plating time are denoted as 1mM-1V-30min, 1mM-3V-30min and 1mM-5V-30min, respectively.

[0045] 1) As shown in Figure 6 , this set of AFM images shows the surface and interface morphology of the samples under the condition of the same concentration (1mM), the same treatment time (30min), but different voltages. Figure 6 (a) and Figure 6 (b) correspond to 1mM-3V-30min, and the surface shows a certain unevenness. As can be seen from the color distribution, there are height differences on the surface. The color scale shows Figure 6 (a) the height range is 421.57nm - 862.54nm, indicating that the Ag layer on the surface of the sample is relatively uniform. Figure 6The height range is 293.1nm -1213nm, indicating that the surface has some undulations, indicating that Ag and Ni coexist at the sample interface. Compared with the image under 3V conditions, Figure 6 (c) Figure 6 (d) corresponds to 1 mM, 1 V, and 30 min. The surface is relatively smooth, with a relatively small range of height variation, as indicated by the color scale. This indicates that at a lower voltage of 1 V, the migration and reaction activity of material particles on the surface is weak, the deposition process is relatively slow and uniform, and the resulting microstructure has less fluctuation. Figure 6 (e) Figure 7 (f) For 1 mM, 5 V, and 30 min, the interface height ranges from -22.7 nm to 811 nm, and the surface height ranges from 15.75 nm to 76.93 nm. As the voltage increases from 1 V to 5 V, the sample surface morphology gradually changes from relatively flat to complex and rough. Comparing different deposition potentials, 3 V provides a moderate electric field driving force, enabling charged particles to migrate and interact on the sample surface. The collision and bonding between particles lead to a diverse surface morphology, and the Ag coating becomes more stable.

[0046] Figure 7 (a) Adhesion force between Ni and Ag at 1mM, 3V, and 30min: The adhesion force distributions of Ni (blue) and Ag (red) show different peaks. The peak of Ni is in the lower force region, while the peak of Ag is in the slightly higher force region, indicating that the adhesion force of the silver layer is higher than that of the Ni layer, which is consistent with the Figure 7 (a) Compared with Figure 7 (c) The force distribution range of 1mM-1V-30min has changed, and the comprehensive peak is in a higher force area than that of the 3V sample. Figure 7 (e) is 1mM-5V-30min, and also shows a multi-peak distribution, with the adhesion force having multiple relatively concentrated value ranges. Figure 7 (b) Figure 7 (d) Figure 4 (f) Analysis of adhesion strength on the electroplated surface at 1mM - 3V - 30min, 1mM - 1V - 30min, and 1mM - 5V - 30min, respectively. The results show a unimodal distribution, with adhesion strength concentrated within a single range. The influence of voltage on the electrodeposition process: Voltage alters the electrodeposition rate and coating structure. High voltages result in rapid ion deposition, potentially forming a loose coating and affecting adhesion. Low voltages result in slower deposition, resulting in a denser coating and potentially varying adhesion. Overall, a deposition potential of 3V is optimal.

[0047] Figure 4 By comparing different electroplating voltages, Figure 4(b) shows that when the voltage is reduced to 1V (1mM - 1V - 30min), the electric driving force in the electroplating process is weakened, the ion migration speed is slowed down, the growth rate of the plated layer is reduced, and the arrangement and bonding mode of atoms at the interface change, so that the adhesion force curve presents different characteristics, such as smaller peak value, flatter curve, etc., indicating that the strength and mode of interface interaction change. Figure 4 (c) shows that when the voltage is increased to 5V (1mM - 5V - 30min), the electric driving force is enhanced, ions quickly migrate and deposit to the electrode surface, resulting in too fast growth of the plated layer, and grain refinement or other structural changes occur, so that the adhesion force curve presents a different morphology from that at low voltage, reflecting the difference in interface bonding characteristics at high voltage. Figure 8 (a) The adhesion energy of the Ag surface at 3V potential (1mM - 3V - 30min) is 7.01765 x 10 -15 J, and the adhesion energy of the Ni interface is 7.00175 x 10 -15 J; the adhesion energy of the Ag surface at 1mM - 1V - 30min is 6.7488 x 10 -15 J, and the adhesion energy of the Ni interface is 6.7472 x 10 -15 J; the adhesion energy of the Ag surface at 1mM - 5V - 30min is 9.6463 x 10 -15 J, and the adhesion energy of the Ni interface is 9.6458 x 10 -15 J. In summary, the adhesion energy is the largest at 5V potential, but the adhesion energy is too large, which may make it difficult for H* to desorb on the sample, so 3V is selected as the best potential.

[0048] 2) From the SEM images of Figure 9 It can be seen that the most silver ions are loaded on the sample of 1mM - 5V - 30min, with an atomic percentage of 4.81%, more than the other two samples.

[0049] 3) The overpotential of 1mM - 1V - 30min, 1mM - 3V - 30min, and 1mM - 5V - 30min is 181, 224, and 209 V, respectively, indicating that the hydrogen evolution performance of the 1mM - 3V - 30min sample is the best. This is consistent with the AFM detection results.

[0050] (3) Different plating times The three Ni-Ag / NF samples obtained in Example 1 with different plating times, the same AgNO3 solution concentration and plating voltage are denoted as 1mM - 3V - 20min, 1mM - 3V - 30min, and 1mM - 3V - 40min, respectively.

[0051] 1) Figure 9(c) 1mM-3V-40min, the surface shows obvious gully or crack-like structure, and there are also some relatively high protruding area. Long time electroplating (40min) leads to stress accumulation during the growth of the coating, or the atomic deposition inhomogeneity is further intensified, so that the surface appears these crack-like defect structures, and the protruding area may be formed by the excessive atomic aggregation growth. Figure 9 (d) 1mM-3V-40min, there is a relatively obvious high line at the interface, representing the existence of some special structure or higher protrusion at the interface, which may be the deposition of Ag layer. The electroplating of 1mM-3V-40min makes the atomic interaction at the interface further develop, but due to the uneven growth of the coating and other factors, the interface appears this relatively prominent structure feature, which is obviously different from the interface morphology of 1mM-3V-30min. Figure 10 (e) 1mM-3V-20min, the surface shows relatively discrete granular structure, and the particle size and distribution have certain differences. This may be because the electroplating time is relatively short, the coating atoms have not been fully deposited and aggregated, and the arrangement of atoms on the surface has not formed a more regular structure, resulting in the surface showing this relatively discrete granular feature.

[0052] Figure 10 (c) The adhesion force of 1mM-3V-20min Ni (blue) and Ag (red) interface, the peak value of Ni is near 20-30nN, and the peak value of Ag is near 30-40nN, which shows that the adhesion force of Ag layer is larger than that of Ni layer. Figure 10 (a) (1mM-3V-30min) compared with, the force value range increases, which may be due to the shortening of the electroplating time, the change of the interface structure and interaction. Figure 10 (d) The adhesion force of 1mM-3V-20min electroplated surface is near 30-40nN, compared with Figure 10 (b) (1mM-3V-30min), the peak position and distribution are different, which shows that the electroplating time affects the adhesion force characteristics of the electroplated surface. Figure 10 (e) The adhesion force of 1mM-3V-40min Ni (blue) and Ag (red) interface, the peak value of Ni is near 20-30nN, and the peak value of Ag is near 40-50nN. Figure 4(f) The adhesion force peak of the plated surface corresponding to 1 mM-3 V-40 min is near 40-50 nN, indicating that the adhesion force characteristics of the plated surface have changed when the plating time is extended to 40 min. As the deposition continues with time, the coating grows. A thin and imperfect coating may be formed at the beginning, and the adhesion force distribution has characteristics; as the time is extended, the coating thickens and the structure gradually changes, and the atomic arrangement, crystallinity, etc. change, affecting the adhesion force. Figure 4 Under the same voltage (3 V) and concentration (1 mM) conditions, Figure 4 (a) Corresponding to 1 mM-3 V-30 min, the vertical displacement curves of Ag and Ni have specific shapes and values. Figure 4 (f) Corresponding to 1 mM-3 V-40 min, the curve shape and value are different compared with 30 min. The change amplitude of the vertical displacement of Ag and Ni at some heights is different, indicating that the vertical displacement characteristics of the material surface under AFM measurement change as the time is extended from 30 min to 40 min, which may be due to the further evolution of the surface structure caused by long-time plating. The adhesion energy of the Ag surface under 40 min deposition time is 6.9232 x 10 -15 J, and the adhesion energy of the Ni interface is 6.92203 x 10 -15 J, which is smaller than the adhesion energy under 30 min deposition time. Figure 4 (a) 1 mM-3 V-30 min and Figure 4 (g) 1 mM-3 V-20 min is also under the conditions of voltage 3 V and concentration 1 mM, Figure 4 The vertical displacement curve of 20 min in (g) is different from Figure 11 The vertical displacement curve of 30 min in (a) in the entire height range, the vertical displacement value and change trend are different. The change of the vertical displacement of Ag and Ni at some heights is relatively flat at 20 min than at 30 min, indicating that the material surface structure is not fully developed when the plating time is short. In summary, the deposition time of 30 min should be selected.

[0053] 2) From the SEM images of Figure 13 It can be seen from the SEM images that the sample of 1 mM-3 V-20 min has the most loaded silver ions, with an atomic percentage of 6.12%, which is more than that of the other two samples.

[0054] 3) The overpotential of 1 mM-3 V-20 min, 1 mM-3 V-30 min and 1 mM-3 V-40 min is 181, 190 and 229 V respectively, indicating that the hydrogen evolution performance of the sample of 1 mM-3 V-30 min is the best. This is consistent with the AFM detection results.

[0055] Example 3: Characterization As can be seen from Example 2, the electrode hydrogen evolution performance of 1 mM-3V-30 min is optimal. Figure 13 (a) is the XPS diagram of Ag (silver) element. Characteristic peaks: two characteristic peaks of Ag 3d are shown, the binding energy of Ag 3d5 / 2 is 368.3 eV, and the binding energy of Ag 3d3 / 2 is 374.3 eV. Through the position and intensity of the two peaks, the chemical state of the silver element in the sample can be determined, which is in the metallic state (Ag 0 ). Figure 13 (b) is the XPS diagram of Ni (nickel) element. Characteristic peaks: two characteristic peaks of Ni 2p are shown, the binding energy of Ni 2p3 / 2 is 710.8 eV, and the binding energy of Ni 2p1 / 2 is 724.3 eV. Figure 13 (c) is the XPS diagram of O (oxygen) element. Characteristic peaks: O 1s characteristic peak appears at 531.2 eV, and O 2s characteristic peak appears at 529.8 eV. Figure 14 (d) is the full spectrum diagram of the analysis element, which shows the XPS signals of various elements in the sample. Characteristic peaks: characteristic peaks of elements such as Ni, O, Ag, and C (carbon) element peak (usually C 1s peak at about 284.8 eV, which is used as an internal standard for peak correction) can be observed.

[0056] As Figure 15 shown, there is a strong diffraction peak at an angle of 44.49°, marked as NiO, corresponding to the (200) crystal face of NiO. Nickel oxide is a common oxide of nickel and has applications in many fields such as catalysis, battery electrode materials, etc. Its strong peak indicates that the content of NiO in the sample is relatively high and is one of the main phases. Ni (metallic nickel): there is a clear diffraction peak at 51.84, marked as Ni, indicating that there is metallic nickel in the sample, corresponding to the (200) crystal face of Ni. Ag2O3 (silver oxide): there is a diffraction peak corresponding to Ag2O3 in the spectrum at 76.7°, although the relative intensity is low, but it indicates that there is such a silver-containing compound in the sample, corresponding to the (400) crystal face of Ag2O3. The peak near 42.3 can be indexed as the (111) face of metallic Ag.

[0057] Example 4: Performance test The electrochemical performance was tested by an electrochemical workstation of Admiral Squidstat Plus model, and a three-electrode system was connected during the test. The working electrode was the seven Ni-Ag / NF electrodes prepared in Example 1 (with Pt-C electrode as a control), the counter electrode was a graphite electrode, the reference electrode was a Hg / HgO electrode, and the electrolyte was a 1 M KOH solution.

[0058] Activation step (CV cycle): parameter settings, voltage window, adjusted according to the target reaction (HER: -0.8~0 V vs. RHE; OER: 1.0~1.8 V vs. RHE), scan rate: 120 mV / s (high scan rate can quickly stabilize the surface state), number of cycles: 30 (activation is considered complete when the CV curve overlap is >95%).

[0059] EIS measurement: Parameter settings: Frequency range: 100 kHz to 0.1 Hz (covering interface dynamics). Amplitude: 10 mV (to ensure linear response). Bias: -0.2 V vs. RHE (close to open-circuit potential) in the HER region.

[0060] LSV test: (1) Parameter setting, scan range: -0.2~-1.2 V vs. RHE (covering the HER active area), scan rate: 5 mV / s (low speed improves resolution), iR compensation: enable 85%-90% compensation (the solution resistance must be measured by EIS first); (2) Data analysis overpotential (η): the potential at a current density of 10 mA / cm2 (in HER).

[0061] ECSA test conditions: voltage window, non-Faraday region (HER catalyst at -0.2~0 V vs. RHE); scan rate gradient: at least 5 scan rates (here 10, 15, 20, 25, 30, 35, 40 mV / s are selected).

[0062] like Figure 12 As shown, at 100mA cm -2 At a current density of 10000 s, the Ni-Ag@NF-1mM-3V-30min sample has good stability. At the initial moment (t = 0s), the potential is about -0.40V (vs. RHE). In the initial period, the potential drops rapidly with time. This may be due to the activation process of the electrode surface, the initial adjustment of the electrode / electrolyte interface, or some unstable surface species reacting or desorbing in the initial stage. In the middle and late stages: As time goes by, the potential decreases gradually. When it is close to 10000 s, the potential tends to stabilize and remains around -0.43V (vs. RHE). This shows that after the initial changes, the electrode system gradually reaches a relatively stable state. Stability evaluation at 100mA cm -2current density, the potential of Ni-Ag@NF-1mM-3V-30min sample decreased obviously in the initial stage, which indicated that there were some changes in the initial stage, which might have some influence on the stability. However, after a long time (close to 10000s), the potential could keep relatively stable. This means that from the overall long time scale, the sample has certain stability at this current density, which can maintain a relatively stable potential in the subsequent reaction process, ensuring the continuous progress of the electrochemical reaction.

[0063] Figure 12 (a) is the LSV curve analysis, showing the linear sweep voltammetry (LSV) curves of samples under different conditions. The abscissa is the potential relative to the reversible hydrogen electrode (RHE), and the ordinate is the current density. By comparing the corresponding limiting current density, half-wave potential, reaction starting potential and overpotential at 10 mA cm 2 It can be seen that except for the Pt-C electrode, the limiting current density of 1mM-3V-30min is relatively high, the half-wave potential (the potential corresponding to half of the limiting current density) is more positive, and the overpotential at 10 mA cm 2 The overpotential is also the lowest except for Pt-C, which can be seen that its hydrogen evolution performance is the best. Figure 16 (b) is the Tafel diagram of samples under different conditions, the abscissa is the logarithm of current density, and the ordinate is the overpotential (η). Different color lines represent different samples (such as Pt-C, Ni-Ag samples with different concentrations and treatment times). The Tafel slope reflects the rate control step of the electrochemical reaction, and the smaller the slope, the faster the reaction rate. Through the Tafel diagram, the kinetic process of the electrochemical reaction can be analyzed to determine the reaction rate constant, reaction mechanism and other information, and the difficulty of the electrochemical reaction under different materials or treatment conditions can be compared. It can be seen that except for the Pt-C sample, the Tafel slope of the 1mM-3V-30min sample is closest to 90, which is 168 mV dec -1, which indicates that its reaction rate is the fastest. FIG. 12(c)-FIG. 12(f) are electrochemical double-layer capacitance (Cdl) related curves of Pt-C, 1 mM-3 V-30 min, 3 mM-3 V-30 min, 5 mM-3 V-30 min, respectively, showing the relationship between current density and potential at different scan rates. In the double-layer region, the current density is linearly related to the scan rate, which can be used to calculate the electrochemical double-layer capacitance (Cdl). Cdl is an important parameter for measuring the number of active sites on the electrode surface and the properties of the electrode / solution interface. By analyzing these curves, the size of Cdl of different samples can be compared, and then the specific surface area and active site density of the electrode material can be evaluated, reflecting the electrochemical activity of the material. ECSA can be calculated by Cdl, the formula is ECSA = Cdl / Cdl0 (Cdl0 is the capacitance per unit area), which reflects the effective surface area involved in the electrochemical reaction. It can be seen that in addition to Pt-C, the active surface area of 1 mM-3 V-30 min is the largest, which is 18.57 mF·cm -2 . In summary, the electrochemical performance of the 1 mM-3 V-30 min sample is the best.

[0064] Figure 16 (a) is LSV curve analysis, showing the linear sweep voltammetry (LSV) curves of the samples at different electrodeposition potentials. The abscissa is the potential relative to the reversible hydrogen electrode (RHE), and the ordinate is the current density. By comparing the corresponding limiting current density, half-wave potential, reaction onset potential and overpotential at 10 mA cm 2 , it can be seen that in addition to the Pt-C electrode, the limiting current density of 1 mM-3 V-30 min is relatively high, the half-wave potential (the potential corresponding to half of the limiting current density) is also more positive, and the overpotential at 10 mA cm 2 is also the lowest among the Pt-C, which is 181 mV, indicating that its hydrogen evolution performance is the best.

[0065] Figure 17 (b) is the Tafel diagram of the samples at different electrodeposition potentials. It can be seen that in addition to the Pt-C sample, the Tafel slope of the 1 mM-3 V-30 min sample is closest to 90, which is 168 mV dec -1,This indicates that the reaction rate is the fastest. Figures 16(c)-16(f) show the electrochemical double layer capacitance (Cdl) curves for Pt-C, 1mM-3V-30min, 1mM-1V-30min, and 1mM-5V-30min, respectively, demonstrating the relationship between current density and potential at different scan rates. In the double layer region, the current density and scan rate are linearly related, which can be used to calculate the electrochemical double layer capacitance (Cdl). Cdl is an important parameter that measures the number of active sites on the electrode surface and the properties of the electrode / solution interface. By analyzing these curves, the Cdl values ​​of different samples can be compared, thereby evaluating the specific surface area and active site density of the electrode material, reflecting the material's electrochemical activity. The ECSA can be calculated from Cdl using the formula ECSA = Cdl / Cdl0 (Cdl0 is the capacitance per unit area), which reflects the effective surface area involved in the electrochemical reaction. It can be seen that except for Pt-C, the active surface area of ​​1 mM-3 V-30 min is the largest, which is 18.57 mF·cm -2 Overall, the 1mM-3V-30min sample has the best electrochemical performance.

[0066] Figure 17 (a) is the LSV curve analysis, showing the linear sweep voltammetry (LSV) curves of the samples at different plating potentials. The abscissa is the potential relative to the reversible hydrogen electrode (RHE), and the ordinate is the current density. By comparing the corresponding limiting current density, half-wave potential, reaction onset potential, and 10 mA cm 2 The overpotential under the current density shows that except for the Pt-C electrode, the limiting current density of 1mM-3V-30min is relatively high, and the half-wave potential (the potential corresponding to half of the limiting current density) is also more positive, 10mA cm 2 The overpotential is also the lowest except for Pt-C, which is 181mV, indicating that it has the best hydrogen evolution performance. ​ (b) is the Tafel diagram of samples at different electroplating times. It can be seen that except for the Pt-C sample, the Tafel slope of the 1mM-3V-30min sample is closest to 90, which is 168mV dec. -1 , indicating that its reaction rate is the fastest. Figures 17 (c) to 17 (f) are the electrochemical double layer capacitance (Cdl) related curves of Pt-C, 1mM-3V-30min, 1mM-3V-20min, and 1mM-3V-20min, respectively. They show the relationship between current density and potential at different scan rates, reflecting the effective surface area involved in the electrochemical reaction. It can be seen that except for Pt-C, the active surface area of ​​1mM-3V-30min is the largest, at 18.57 mF·cm -2Overall, the 1 mM-3V-30 min sample had the best electrochemical performance.

[0067] The above only is the preferred embodiment of the present application, and is not used to limit the present application, for the person skilled in the art, the present application can have various changes and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. Application of atomic force microscopy in detecting hydrogen evolution performance of electrodes, characterized in that: The electrode is prepared by an electrodeposition method, and the material of the electrode is Ni-Ag / NF.

2. The use according to claim 1, characterized in that The Ni-Ag / NF was prepared by the following method: (1) washing the nickel foam to obtain pretreated nickel foam; (2) Using pretreated nickel foam as cathode, graphite as anode, and silver plating solution as electrolyte, constant voltage method is used for electroplating to transform nickel foam into Ni-Ag / NF.

3. The use according to claim 2, characterized in that In step (1), the pretreatment is as follows: firstly, the nickel foam is ultrasonically degreased in ethanol, rinsed with deionized water, then soaked in a hydrochloric acid solution, then ultrasonicated with deionized water, and finally dried to obtain the pretreated nickel foam.

4. The use according to claim 2, characterized in that In step (2), the silver plating solution is obtained by mixing a silver nitrate solution and an ammonia buffer solution; the ammonia buffer solution is prepared by dissolving NH4Cl and KNO3 in ultrapure water, adding concentrated ammonia water, and then adding ultrapure water and mixing evenly; the concentration of the silver nitrate solution is 1~5mM.

5. The use according to claim 4, characterized in that The concentration of NH4Cl in the ammonia buffer solution is 0.1M, and the concentration of KNO3 is 0.1M; the volume of the concentrated ammonia water accounts for 35% of the volume of the ammonia buffer solution; and the volume ratio of the ammonia buffer solution to the silver nitrate solution is 1:

7.

6. The use according to claim 2, characterized in that In step (2), the electroplating voltage is 1-5V and the time is 20-40min.

7. A method for detecting the hydrogen evolution performance of an electrode using an atomic force microscope, characterized in that: The method is: The electrode prepared by electrodeposition is placed under an atomic force microscope. Using the single-molecule force spectroscopy method of the atomic force microscope, the probe of the atomic force microscope is kept in contact with the electrode to generate a force-distance curve. The adhesion energy of the deposited material on the electrode is calculated based on the force-distance curve. The greater the adhesion energy, the better the hydrogen evolution performance of the electrode.

8. The method according to claim 7, characterized in that The contacting is as follows: at least 10 points are selected on the electrode, and the probe of the atomic force microscope is in continuous contact with the selected points for at least 50 times.

9. The method according to claim 7, characterized in that The material of the electrode is Ni-Ag / NF; the Ni-Ag / NF is prepared by the following method: (1) washing the nickel foam to obtain pretreated nickel foam; (2) Using pretreated nickel foam as cathode, graphite as anode, and silver plating solution as electrolyte, constant voltage method is used for electroplating to transform nickel foam into Ni-Ag / NF.

10. The method according to claim 7, characterized in that The calculation formula of the adhesion energy is: ; Where F(d) is the interaction force between the probe and the electrode, which varies with the distance d; d1 is the initial distance at which the probe contacts the electrode; and d2 is the distance at which the probe completely separates from the electrode.

Images