Preparation method of alkaline hydrogen production bifunctional electrode for industrialization and application thereof

Abstract

The application discloses a preparation method of an industrial alkaline hydrogen production bifunctional electrode and application thereof, and belongs to the technical field of water electrolysis hydrogen production electrodes. The application obtains an industrial alkaline hydrogen production bifunctional electrode by performing electrodeposition on a pretreated conductive substrate as a cathode in an electrolyte; wherein, during the electrodeposition process, the conductive substrate swings left and right relative to an anode, and the electrolyte is subjected to cyclic disturbance. The industrial alkaline hydrogen production bifunctional electrode prepared based on the left-right swinging of the conductive substrate and the cyclic disturbance of the electrolyte has excellent uniformity, catalytic activity and stability, solves the problems of the prior art hydrogen production electrode, such as difficulty in amplification, high cost, low activity, short service life and the like, and is suitable for large-scale industrial production and application.

Description

Technical Field

[0001] This invention belongs to the field of electrolytic water hydrogen production electrode technology, specifically relating to a method for preparing an industrial-grade alkaline hydrogen production bifunctional electrode and its application. Background Technology

[0002] With the development of renewable energy, hydrogen energy has received widespread attention as a clean and efficient energy carrier. Electrochemical water splitting for hydrogen production can transform intermittent renewable energy into sustainable industrial production and reduce greenhouse gas emissions. Alkaline water electrolyzers are the earliest and most mature electrochemical water splitting technology, offering scalability advantages for industrial-scale hydrogen production. However, traditional Raney nickel electrocatalysts, primarily used in alkaline electrolyzers, are struggling to meet the current demands for higher energy efficiency and cost-effectiveness in green hydrogen production. Meanwhile, the mechanical, structural, and chemical stability of electrodes are key indicators determining the lifespan of electrode materials.

[0003] Although many promising electrocatalytic materials have been developed using simple preparation methods in the laboratory, their application in commercial alkaline electrolyzers has not received much attention. This is largely due to academic neglect of specific operating conditions, key performance indicators, and material costs associated with industrial applications, as well as the overlooked impact of large-scale electrode manufacturing processes on catalytic performance. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a method for preparing an industrial-grade alkaline bifunctional electrode for hydrogen production and its application. To address the problems of difficult scale-up, high cost, and short lifespan of hydrogen production electrodes, this invention prepares an industrial-grade alkaline bifunctional electrode for hydrogen production based on the left-right swaying of a conductive substrate and electrolyte circulation disturbance. The prepared electrode exhibits excellent uniformity, catalytic activity, and stability.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] This invention provides a method for preparing an industrially applicable alkaline hydrogen production bifunctional electrode, comprising the following steps:

[0007] The pretreated conductive substrate was used as the cathode and electrodeposited in the electrolyte to obtain a bifunctional alkaline hydrogen production electrode for industrial applications.

[0008] During the electrodeposition process, the conductive substrate oscillates from side to side relative to the anode, and the electrolyte is circulated and disturbed.

[0009] Preferably, the left-right swaying refers to the conductive substrate alternately moving closer to and further away from the anode.

[0010] Preferably, the frequency of the left-right swaying is 0.1-1Hz, the amplitude is 5-15cm, and the amplitude is less than the distance between the cathode and the anode.

[0011] More preferably, the frequency of the left-right swaying is 0.2-0.8Hz, and the amplitude is 5-10cm.

[0012] More preferably, the frequency of the left and right swaying is 0.1 Hz and the amplitude is 5 cm.

[0013] Preferably, the cycle rate of the cyclic disturbance is 2-10 cylinders per hour.

[0014] More preferably, the cycle rate of the cyclic disturbance is 3-6 cylinders per hour.

[0015] More preferably, the cycle rate of the cyclic disturbance is 5 cylinders per hour.

[0016] Preferably, the cyclic disturbance is achieved by a row of cyclic nozzles parallel to the width or height direction of the conductive substrate, with the cyclic nozzles located on the side of the conductive substrate closer to the anode and oriented towards the conductive substrate.

[0017] More preferably, when a row of circulating nozzles is parallel to the width direction of the conductive substrate, the direction of the circulating nozzles is perpendicular to and corresponds to the centerline of the height direction of the cathode substrate, the vertical distance between the circulating nozzles and the cathode substrate is 5-10cm, and the height direction distance from the center of the cathode substrate is 20-30cm; when a row of circulating nozzles is parallel to the height direction of the conductive substrate, the direction of the circulating nozzles is perpendicular to and corresponds to the centerline of the width direction of the cathode substrate, the vertical distance between the circulating nozzles and the cathode substrate is 5-10cm, and the width direction distance from the center of the cathode substrate is 20-30cm.

[0018] More preferably, the diameter of the circulating nozzle is 20-30mm.

[0019] Preferably, the distance between the cathode and the anode is 5-30 cm.

[0020] Preferably, the anode is a nickel plate or a nickel ball.

[0021] Preferably, the conductive substrate is a nickel substrate.

[0022] More preferably, the nickel substrate is a nickel mesh, nickel foam, or nickel felt.

[0023] Preferably, the size of the conductive substrate is 20-50cm × 20-50cm.

[0024] Preferably, the pretreatment is pickling and cleaning.

[0025] Preferably, the electrolyte is a nickel-containing electrolyte.

[0026] Preferably, the electrolyte comprises: 30-70 g / L nickel ions, 15-30 g / L buffer reagent, 10-20 g / L stabilizer, 50-100 g / L conductive salt, 3-5 g / L sodium dodecyl sulfate, and the balance being water. The electroplating solution of this invention is easy to prepare, relatively inexpensive, and the production process is easy to control, making it suitable for large-scale industrial production.

[0027] More preferably, the electrolyte comprises: 40 g / L nickel ions, 15 g / L buffer reagent, 15 g / L stabilizer, 50 g / L conductive salt, 3 g / L sodium dodecyl sulfate, and the balance being water.

[0028] More preferably, the nickel ions are provided by a nickel salt, which is one or more of nickel sulfate (NiSO4), nickel aminosulfonate (Ni(SO3NH2)2), nickel nitrate, and nickel acetate (Ni(CH3COO)2).

[0029] More preferably, the buffer reagent is boric acid or phosphoric acid.

[0030] More preferably, the stabilizer is sodium citrate.

[0031] More preferably, the conductive salt is one or more of ammonium chloride, sodium chloride, and sodium sulfate.

[0032] Preferably, the pH of the electrolyte is 2.0-6.0.

[0033] More preferably, the pH of the electrolyte is 5.

[0034] Preferably, the temperature of the electrolyte is 20-70°C.

[0035] More preferably, the temperature of the electrolyte is 60±2℃.

[0036] Preferably, the electrodeposition comprises 8-30 A / dm³. 2 Electrodeposition for 10-200 seconds, 0.2-6 A / dm 2 Electrodeposition takes 10-60 minutes. This invention effectively solves the problems of poor adhesion of the catalyst layer, low activity, and poor overall stability of traditional electrode materials by combining high-current impact plating with appropriate current density deposition.

[0037] This invention provides an industrial-grade alkaline hydrogen production bifunctional electrode prepared by the above-described method. The electrode prepared by this invention consists of a dense and strongly bonded bottom layer and a highly active surface layer with a special morphology. The synergistic effect of these two layers enhances the electrode's catalytic activity and stability, significantly reducing the energy consumption of the electrolyzer and improving hydrogen production efficiency. The surface morphology can be optimized by adjusting electroplating parameters, such as forming a nanosheet stacked structure, to expose more catalytically active sites and improve electrolysis efficiency.

[0038] This invention provides an application of the above-mentioned industrial-grade alkaline hydrogen production bifunctional electrode in water electrolysis for hydrogen production.

[0039] Preferably, the industrial-grade alkaline hydrogen production bifunctional electrode serves as the cathode and / or anode in water electrolysis for hydrogen production.

[0040] Preferably, the current density for hydrogen production via water electrolysis is 10-1000 mA / cm². 2 .

[0041] Preferably, the electrolyte for producing hydrogen by electrolysis of water is an alkaline electrolyte.

[0042] More preferably, the alkaline electrolyte is a 1-8 mol / L KOH solution.

[0043] The beneficial effects of this invention are:

[0044] The present invention provides an industrial-grade alkaline hydrogen production bifunctional electrode based on the left-right swaying of a conductive substrate and the electrolyte circulation disturbance. This electrode exhibits excellent uniformity, catalytic activity, and stability, solving the problems of existing hydrogen production electrodes, such as difficulty in scaling up, high cost, low activity, and short lifespan. It is suitable for large-scale industrial production and application. Attached Figure Description

[0045] Figure 1 The image shows a physical picture (left) and a partial SEM image (right) of the electrode product prepared in Example 1 of the present invention.

[0046] Figure 2 The image shows the physical sample (left) and a partial SEM image (right) of the electrode product prepared in Example 2 of this invention.

[0047] Figure 3 The image shows a physical picture (left) and a partial SEM image (right) of the electrode product prepared in Example 3 of the present invention.

[0048] Figure 4 The image shows a physical picture (left) and a partial SEM image (right) of the electrode product prepared in Example 4 of the present invention.

[0049] Figure 5 This is a SEM cross-sectional view of the electrode product prepared in Example 4 of the present invention;

[0050] Figure 6 A comparative data graph of ultrasonic weight loss test results between the electrode product prepared in Example 4 of this invention and the Raney nickel electrode.

[0051] Figure 7 The hydrogen evolution reaction (HER) LSV curves of the electrode products prepared in Examples 1-4 of this invention were obtained by tailoring the electrodes.

[0052] Figure 8 The oxygen evolution reaction (OER) LSV curves of the electrode products prepared in Examples 1-4 of this invention were obtained by cutting the electrodes.

[0053] Figure 9 The electrodes prepared in Examples 1-4 of this invention were cut into upper, middle, and lower regions at 3000 A / m. 2 Overpotential of hydrogen evolution reaction at current density;

[0054] Figure 10 The electrodes prepared in Examples 1-4 of this invention were cut into upper, middle, and lower regions at 3000 A / m. 2 Overpotential of oxygen evolution reaction at current density;

[0055] Figure 11 The electrode product prepared in Example 4 of this invention, after being actually assembled into an electrolytic cell, operates at 5000 A / m 2 The time-average cell voltage curve after 100 days of operation at current density;

[0056] Figure 12 This is a schematic diagram of the circulating nozzle and cathode in the electrode preparation process of this invention. Detailed Implementation

[0057] The present invention will be further described below with reference to embodiments.

[0058] The following will clearly and completely describe the concept, specific solutions, and technical effects of the present invention with reference to embodiments, so as to fully understand the purpose, features, and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. The various technical features in the present invention can be combined interactively without contradicting each other.

[0059] This invention uses a nickel plate or nickel ball as a sacrificial anode and a nickel salt as the nickel source in the electroplating solution. A pre-plating layer is first deposited on the substrate by high-current impact, followed by the deposition of a catalyst layer. The electrode as a whole is a pure nickel material system, which can be used simultaneously as the cathode and anode for alkaline water electrolysis hydrogen production. It has a high specific surface area, and the catalyst layer and substrate layer have excellent adhesion, effectively improving the problems of low activity and poor coating adhesion in existing hydrogen production electrodes. This invention's method is easy to scale up industrially, with controllable production costs, and solves the problems of existing electrodes being difficult to scale up, having poor catalyst layer adhesion, and short lifespan. The electrode prepared by this method is suitable for the renewable energy alkaline water electrolysis hydrogen production industry.

[0060] This invention provides a method for preparing an industrially applicable alkaline hydrogen production bifunctional electrode, comprising the following steps:

[0061] S1. Substrate pretreatment.

[0062] First, cut the conductive substrate to the required size. Then, immerse the cut conductive substrate material in a solution containing acid and surfactant and sonicate it for 2-5 minutes. Next, rinse the ultrasonically cleaned substrate material with deionized water for 2-5 minutes. Repeat this process three times until there is virtually no surfactant residue.

[0063] S2. Electrodeposition.

[0064] The pretreated conductive substrate is fixed on a fixture as the cathode, and a nickel plate of similar size serves as the anode. Both are vertically immersed in the electroplating solution, which is at a temperature of 20-70℃. The solution is circulated and agitated by a row of nozzles parallel to the width or height of the conductive substrate. The circulation rate is 3-6 cylinders per hour. The nozzles are positioned on the conductive substrate near the anode, and their direction is towards the substrate. When the nozzles are parallel to the width of the substrate, their direction is perpendicular to and corresponds to the centerline of the cathode substrate's height (the extension of the nozzle direction passes through the centerline of the un-oscillated conductive substrate's height). The vertical distance is 5-10cm, and the height distance from the center of the cathode substrate is 20-30cm. When a row of circulating nozzles is parallel to the height direction of the conductive substrate, the direction of the circulating nozzles is perpendicular to and corresponds to the centerline of the width direction of the cathode substrate (the extension line of the circulating nozzle direction passes through the centerline of the width direction of the un-oscillating conductive substrate). The vertical distance between the circulating nozzles and the cathode substrate is 5-10cm, and the width distance from the center of the cathode substrate is 20-30cm. The diameter of the circulating nozzles is 20-30mm. The distance between the anode and cathode is 5-30cm. The frequency of the conductive substrate oscillating relative to the anode is 0.1-1Hz, and the amplitude is 5-15cm. Electrodeposition is performed by applying current. First, a high current density is used for impact electrodeposition to rapidly deposit nickel ions on the substrate surface to form a dense and strongly bonded bottom layer. The current density for high current impact electrodeposition is 8-30 A / dm³. 2 The time is 10-200 seconds. Reduce the current density to the desired value of 0.2-6 A / dm. 2 Continue to deposit to form a high specific surface area and high activity surface layer with a special morphology. The electroplating time is 10-60 minutes.

[0065] S3. Post-treatment of electrodes.

[0066] The deposited electrodes are subjected to two high-temperature spray water washes, two room-temperature spray water washes, and drying to remove surface residues.

[0067] The conductive substrate in step S1 is a nickel mesh, nickel foam, or nickel felt; the nickel foam has a thickness of 1.0-2.2 mm, preferably 1.2-1.6 mm, a pore density of 50-150 ppi, and an areal density of 200-500 g / m³. 2 The nickel mesh has a wire diameter of 0.15-0.3 mm and a mesh count of 20-60; the nickel felt has a porosity of 50%-80% and a pore size greater than 10 μm.

[0068] The electroplating solution in step S2 comprises: 30-70 g / L nickel ions, 15-30 g / L buffer, 10-20 g / L stabilizer, 50-100 g / L conductive salt, 3-5 g / L sodium dodecyl sulfate, and the balance being water. The nickel ions are provided by nickel salts, which can be nickel sulfate (NiSO4), nickel sulfamate (Ni(SO3NH2)2), nickel nitrate (Ni(NO3)2), or nickel acetate (Ni(CH3COO)2). The buffer can be boric acid or phosphoric acid, the stabilizer can be sodium citrate, and the conductive salt can be ammonium chloride, sodium chloride, sodium sulfate, etc.

[0069] The pH value of the electroplating solution in step S2 is 2.0-6.0.

[0070] The purity of the nickel plate in step S2 is ≥99.99%.

[0071] The high-temperature spray washing in step S3 is at a temperature of 50-90℃, and the normal-temperature spray washing is at a temperature of 20-40℃. The drying is done by forced-air drying with an air volume of 0.05-1 Nm³. 3 / h, drying temperature less than 40℃.

[0072] The above-described method produces an industrially applicable alkaline hydrogen production bifunctional electrode. Its catalytic active layer is made of pure nickel, without doping or mixing with other metal elements. The thickness of the pre-plated layer is 10-50 nm, and the thickness of the catalytic layer is 100-2000 nm.

[0073] The cyclic stirring disturbance in the following embodiments of the present invention is achieved by a row of circulating nozzles parallel to the width direction of the conductive substrate, as shown in the schematic diagram. Figure 12 The circulating nozzle is located on the conductive substrate near the anode side, below the conductive substrate. The direction of the circulating nozzle is perpendicular to and corresponds to the center line of the cathode substrate in the height direction (the extension of the direction of the circulating nozzle passes through the center line of the non-oscillating conductive substrate in the height direction). The vertical distance (horizontal distance) between the circulating nozzle and the cathode substrate is 5cm, and the height direction distance (vertical distance) between the circulating nozzle and the center of the cathode substrate is 20cm. The diameter of the circulating nozzle is 25mm.

[0074] Example 1

[0075] A method for preparing an alkaline hydrogen production bifunctional electrode includes the following steps:

[0076] (1) Pretreatment of conductive substrate: Select 1.6 mm thick nickel foam as conductive substrate, cut the nickel foam into 30 cm × 30 cm size, perform acid washing and degreasing operation in a solution containing hydrochloric acid and sodium dodecyl sulfate, and then rinse the nickel foam substrate with deionized water for 5 min. Repeat three times to obtain the pretreated nickel foam substrate.

[0077] (2) Preparation of electroplating solution: Nickel sulfate is used as the main salt, with a nickel ion concentration of 40 g / L; boric acid concentration of 15 g / L; sodium citrate concentration of 15 g / L; sodium chloride concentration of 50 g / L; sodium dodecyl sulfate concentration of 3 g / L; the remainder is water; the solution pH is 5, and the temperature is 60 ± 2 °C.

[0078] (3) Arrangement of electroplating apparatus: A pre-treated 30cm×30cm foam nickel substrate is used as the cathode, and an etched nickel plate is used as the anode. The purity of the nickel plate is above 99.99%. The cathode and anode are simultaneously placed into the prepared electroplating solution, with a distance of 20cm between them. The electroplating solution is not circulated or stirred. The conductive substrate does not sway relative to the anode.

[0079] (4) First, shock electrodeposition is performed using a high current density of 10 A / dm. 2 The time is 20 seconds.

[0080] (5) After high-current impact electrodeposition, adjust the current density through the anode and cathode to 3A / dm. 2 The power-on time is 40 minutes.

[0081] (6) Post-treatment of electrodes: After the energizing time is up, take out the electrodes and clean them with hot water and cold water respectively. The cleaning time is between 3-5 minutes. Then take out the electrodes and dry them with a forced air at room temperature to obtain the finished electrode.

[0082] Example 2

[0083] A method for preparing an alkaline hydrogen production bifunctional electrode includes the following steps:

[0084] (1) Pretreatment of conductive substrate: Select 1.6 mm thick nickel foam as conductive substrate, cut the nickel foam into 30 cm × 30 cm size, perform acid washing and degreasing operation in a solution containing hydrochloric acid and sodium dodecyl sulfate, and then rinse the nickel foam substrate with deionized water for 5 min. Repeat three times to obtain the pretreated nickel foam substrate.

[0085] (2) Preparation of electroplating solution: Nickel sulfate is used as the main salt, with a nickel ion concentration of 40 g / L; boric acid concentration of 15 g / L; sodium citrate concentration of 15 g / L; sodium chloride concentration of 50 g / L; sodium dodecyl sulfate concentration of 3 g / L; the remainder is water; the solution pH is 5, and the temperature is 60 ± 2 °C.

[0086] (3) Arrangement of electroplating apparatus: A pre-treated 30cm×30cm foam nickel substrate is used as the cathode, and an etched nickel plate is used as the anode. The purity of the nickel plate is above 99.99%. The cathode and anode are simultaneously placed into the prepared electroplating solution, with a distance of 20cm between them. The electroplating solution is circulated and stirred at a rate of 5 cylinders per hour. The conductive substrate does not sway relative to the anode.

[0087] (4) First, shock electrodeposition is performed using a high current density of 10 A / dm. 2 The time is 20 seconds.

[0088] (5) After high-current impact electrodeposition, adjust the current density through the anode and cathode to 3A / dm. 2 The power-on time is 40 minutes.

[0089] (6) Post-treatment of electrodes: After the energizing time is up, take out the electrodes and clean them with hot water and cold water respectively. The cleaning time is between 3-5 minutes. Then take out the electrodes and dry them with a forced air at room temperature to obtain the finished electrode.

[0090] Example 3

[0091] A method for preparing an alkaline hydrogen production bifunctional electrode includes the following steps:

[0092] (1) Pretreatment of conductive substrate: Select 1.6 mm thick nickel foam as conductive substrate, cut the nickel foam into 30 cm × 30 cm size, perform acid washing and degreasing operation in a solution containing hydrochloric acid and sodium dodecyl sulfate, and then rinse the nickel foam substrate with deionized water for 5 min. Repeat three times to obtain the pretreated nickel foam substrate.

[0093] (2) Preparation of electroplating solution: Nickel sulfate is used as the main salt, with a nickel ion concentration of 40 g / L; boric acid concentration of 15 g / L; sodium citrate concentration of 15 g / L; sodium chloride concentration of 50 g / L; sodium dodecyl sulfate concentration of 3 g / L; the remainder is water; the solution pH is 5, and the temperature is 60 ± 2 °C.

[0094] (3) Arrangement of electroplating apparatus: A pretreated 30cm×30cm foam nickel substrate is used as the cathode, and an etched nickel plate is used as the anode. The purity of the nickel plate is above 99.99%. The cathode and anode are simultaneously placed in the prepared electroplating solution, with a distance of 20cm between them. The electroplating solution is not circulated or stirred. The frequency of the conductive substrate swinging from side to side relative to the anode is 0.1Hz, and the amplitude is 5cm.

[0095] (4) First, shock electrodeposition is performed using a high current density of 10 A / dm. 2 The time is 20 seconds.

[0096] (5) After high-current impact electrodeposition, adjust the current density through the anode and cathode to 3A / dm. 2 The power-on time is 40 minutes.

[0097] (6) Post-treatment of electrodes: After the energizing time is up, take out the electrodes and clean them with hot water and cold water respectively. The cleaning time is between 3-5 minutes. Then take out the electrodes and dry them with a forced air at room temperature to obtain the finished electrode.

[0098] Example 4

[0099] A method for preparing an industrially applicable alkaline hydrogen production bifunctional electrode includes the following steps:

[0100] (1) Pretreatment of conductive substrate: Select 1.6 mm thick nickel foam as conductive substrate, cut the nickel foam into 30 cm × 30 cm size, perform acid washing and degreasing operation in a solution containing hydrochloric acid and sodium dodecyl sulfate, and then rinse the nickel foam substrate with deionized water for 5 min. Repeat three times to obtain the pretreated nickel foam substrate.

[0101] (2) Preparation of electroplating solution: Nickel sulfate is used as the main salt, with a nickel ion concentration of 40 g / L; boric acid concentration of 15 g / L; sodium citrate concentration of 15 g / L; sodium chloride concentration of 50 g / L; sodium dodecyl sulfate concentration of 3 g / L; the remainder is water; the solution pH is 5, and the temperature is 60 ± 2 °C.

[0102] (3) Arrangement of electroplating apparatus: A pre-treated 30cm×30cm foam nickel substrate is used as the cathode, and an etched nickel plate is used as the anode. The purity of the nickel plate is above 99.99%. The cathode and anode are simultaneously placed into the prepared electroplating solution, with a distance of 20cm between them. The electroplating solution is circulated and stirred at a rate of 5 cylinders per hour. The frequency of the conductive substrate swinging left and right relative to the anode is 0.1Hz, and the amplitude is 5cm.

[0103] (4) First, shock electrodeposition is performed using a high current density of 10 A / dm. 2 The time is 20 seconds.

[0104] (5) After high-current impact electrodeposition, adjust the current density through the anode and cathode to 3A / dm. 2 The power-on time is 40 minutes.

[0105] (6) Post-treatment of electrodes: After the energizing time is up, take out the electrodes and clean them with hot water and cold water respectively. The cleaning time is between 3-5 minutes. Then take out the electrodes and dry them with a forced air at room temperature to obtain the finished electrode.

[0106] Sample characterization and performance testing:

[0107] (1) The electrode products prepared in Examples 1-4 were photographed and scanned using an electron microscope. The results are as follows: Figure 1-4 .

[0108] (2) The cross-section of the electrode product prepared in Example 4 was scanned by an electron microscope, and the results are as follows: Figure 5 .

[0109] (3) The adhesion of the coating on the electrode product prepared in Example 4 was evaluated. One 4cm×4cm electrode was cut from the upper, middle and lower regions of the electrode product. The weights of the electrodes were recorded using an analytical balance with an accuracy of 0.1mg. The electrodes were then ultrasonically treated in 20%wt.KOH medium for 2 hours using an ultrasonic cleaner with an ultrasonic power of 300W. After ultrasonic treatment, the alkaline solution on the electrode surface was thoroughly cleaned with deionized water. The electrodes were then dried thoroughly in a vacuum drying oven at 70℃ for 2 hours. The weights of the electrodes were recorded using an analytical balance. The adhesion strength of the coating was evaluated by the weight loss rate relative to the original weight of the sample. For comparison, a horizontal comparison was made with Raney nickel electrodes used on a large scale in industry. The test results are as follows. Figure 6 As shown.

[0110] (4) Electrochemical activity tests were performed on the electrode products prepared in Examples 1-4: A 1cm × 1cm electrode was randomly cut from the electrode products, and the catalytic kinetics of water splitting was tested on an electrochemical workstation using a three-electrode system. The prepared electrode was used as the working electrode, with a test area of ​​1cm × 1cm. A 3cm × 3cm nickel mesh was used as the counter electrode, and the reference electrode was a Hg / HgO electrode. The electrolyte was a 1 mol / L KOH aqueous solution. The polarization curve of the electrode was tested using linear sweep voltammetry. The potential range for the hydrogen evolution reaction (HER) was 0 - (-0.4V) vs. RHE. The LSV curve of the HER is shown below. Figure 7 As shown; the potential scan range for the oxygen evolution reaction (OER) was 1.13–1.91 V vs. RHE, using 85% iR potential compensation, with a scan rate of 5 mV / s. The OER LSV curve is shown below. Figure 8 As shown.

[0111] (5) Electrochemical activity tests were conducted on the electrode products prepared in Examples 1-4: One 1cm × 1cm electrode was cut from each of the upper, middle, and lower regions of the electrode product. The catalytic kinetics of water splitting was tested on an electrochemical workstation using a three-electrode system. The prepared electrode served as the working electrode, with a test area of ​​1cm × 1cm. A 3cm × 3cm nickel mesh was used as the counter electrode, and the reference electrode was a Hg / HgO electrode. The electrolyte was a 1 mol / L KOH aqueous solution. The polarization curve of the electrode was tested using linear sweep voltammetry. The potential range for the hydrogen evolution reaction was 0 - (-0.4V) vs. RHE, 3000 A / m. 2 The overpotential of hydrogen evolution reaction at current density is as follows: Figure 9 As shown; the potential scan range for the oxygen evolution reaction was 1.13–1.91 V vs. RHE, using 85% iR potential compensation, with a scan rate of 5 mV / s and 3000 A / m. 2 Oxygen evolution reaction overpotential at current density such as Figure 10 As shown.

[0112] (6) Conduct actual cell tests on industrial electrolyzer electrodes: In a cell with a rated hydrogen production capacity of 2 Nm³, 2 The electrodes were tested in a practical application on an alkaline water electrolysis hydrogen production system with a capacity of 1 h. Both the cathode and anode of the electrolyzer used the electrodes prepared in Example 4 of this invention. The diaphragm was a commonly used industrial PPS diaphragm. The operating temperature was 85±2℃, the system operating pressure was 1.6 MPa, and the current density was 5000 A / m. 2 The electrical safety was tested, and the machine was operated for 100 days under daily on / off conditions. The results were as follows: Figure 11 As shown.

[0113] Data Analysis:

[0114] (1) From Figure 1-4 It can be seen that the morphology of the electrode is greatly improved after adding cycling and rocking. From a macroscopic point of view, the uniformity of the electrode surface is greatly improved. From the scanning electron microscope image, the microstructure of the electrode prepared without cycling and rocking is relatively disordered and quite different. After adding cycling and rocking, the microstructure is more robust and more ordered.

[0115] (2) From Figure 5 It can be seen that the electrode product prepared in Example 4 has a pre-plating layer between the catalyst layer 1 and the substrate 2, which effectively solves the problem of poor bonding between the catalyst and the substrate. At the same time, the rough structure of the catalyst layer 1 provides more active sites for the reaction.

[0116] (3) From Figure 6 It can be seen that the Raney nickel electrode has a 3-5 times higher ultrasonic weight loss rate than the electrode catalyst layer prepared in Example 4 of this invention.

[0117] (4) From Figure 7-8 It can be seen that the oxygen evolution overpotential and hydrogen evolution overpotential are both better after cycling and rocking; furthermore, cycling and rocking at the same time have a synergistic effect on the electrode performance.

[0118] (5) From Figure 9-10 It can be seen that the performance of both oxygen evolution overpotential and hydrogen evolution overpotential is better after adding circulation and rocking. The overpotentials at different positions of the upper, middle and lower parts of the electrode differ greatly when neither circulation nor rocking is added, while the performance difference at each position becomes smaller after adding circulation and rocking. Furthermore, adding circulation and rocking at the same time has a synergistic effect on the performance of the electrode.

[0119] (6) From Figure 11 It can be seen that within the first 5 days, the average cell voltage of the electrolyzer dropped from 2.07V to 1.95V, indicating that the electrode described in this invention undergoes an activation process during operation. As the operating time increases, the electrode performance improves, stabilizing around 5 days. It also exhibits good stability under actual daily start-up and shutdown conditions, demonstrating good compatibility with the actual operating conditions of renewable energy hydrogen production.

[0120] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. A method for preparing an industrially applicable alkaline hydrogen production bifunctional electrode, characterized in that, Includes the following steps: The pretreated conductive substrate was used as the cathode and electrodeposited in the electrolyte to obtain a bifunctional alkaline hydrogen production electrode for industrial applications. During the electrodeposition process, the conductive substrate oscillates from side to side relative to the anode, and the electrolyte is circulated and disturbed. The left-right swaying refers to the conductive substrate alternately moving closer to and away from the anode; The cyclic disturbance is achieved by a row of cyclic nozzles parallel to the width or height direction of the conductive substrate. The cyclic nozzles are located on the side of the conductive substrate closer to the anode, and the direction of the cyclic nozzles is towards the conductive substrate. When a row of circulating nozzles is parallel to the width direction of the conductive substrate, the direction of the circulating nozzles is perpendicular to and corresponds to the centerline of the height direction of the cathode substrate; when a row of circulating nozzles is parallel to the height direction of the conductive substrate, the direction of the circulating nozzles is perpendicular to and corresponds to the centerline of the width direction of the cathode substrate. The electrolyte comprises: nickel ions 30-70 g / L, buffer reagent 15-30 g / L, stabilizer 10-20 g / L, conductive salt 50-100 g / L, sodium dodecyl sulfate 3-5 g / L, and the balance being water; The electrodeposition process sequentially includes 8-30 A / dm 2 Electrodeposition for 10-200 seconds, 0.2-6 A / dm 2 Electrodeposition for 10-60 minutes.

2. The method for preparing an industrial-grade alkaline hydrogen production bifunctional electrode according to claim 1, characterized in that, The left-right swaying frequency is 0.1-1Hz, the amplitude is 5-15cm, and the amplitude is less than the distance between the cathode and the anode.

3. The method for preparing an industrial-grade alkaline hydrogen production bifunctional electrode according to claim 1, characterized in that, The circulation rate of the cyclic disturbance is 2-10 cylinders per hour; When a row of circulating nozzles is parallel to the width direction of the conductive substrate, the direction of the circulating nozzles is perpendicular to and corresponds to the centerline of the height direction of the cathode substrate. The vertical distance between the circulating nozzles and the cathode substrate is 5-10cm, and the height direction distance from the center of the cathode substrate is 20-30cm. When a row of circulating nozzles is parallel to the height direction of the conductive substrate, the direction of the circulating nozzles is perpendicular to and corresponds to the centerline of the width direction of the cathode substrate. The vertical distance between the circulating nozzles and the cathode substrate is 5-10cm, and the width direction distance from the center of the cathode substrate is 20-30cm. The diameter of the circulating nozzle is 20-30mm.

4. The method for preparing an industrial-grade alkaline hydrogen production bifunctional electrode according to claim 1, characterized in that, The distance between the cathode and the anode is 5-30cm; The anode is a nickel plate or a nickel ball; The conductive substrate is a nickel substrate; The nickel substrate is nickel mesh, nickel foam, or nickel felt; The conductive substrate has dimensions of 20-50cm × 20-50cm; The pretreatment includes pickling and cleaning; The electrolyte is a nickel-containing electrolyte.

5. The method for preparing an industrial-grade alkaline hydrogen production bifunctional electrode according to claim 1, characterized in that, The pH of the electrolyte is 2.0-6.0; The temperature of the electrolyte is 20-70℃.

6. The method for preparing an industrial-grade alkaline hydrogen production bifunctional electrode according to claim 5, characterized in that, The electrolyte comprises: 40 g / L nickel ions, 15 g / L buffer reagent, 15 g / L stabilizer, 50 g / L conductive salt, 3 g / L sodium dodecyl sulfate, and the remainder is water. The nickel ions are provided by a nickel salt, which is one or more of nickel sulfate, nickel sulfamate, nickel nitrate, and nickel acetate. The buffer reagent is boric acid or phosphoric acid; The stabilizer is sodium citrate; The conductive salt is one or more of ammonium chloride, sodium chloride, and sodium sulfate.

7. An industrially-oriented alkaline hydrogen production bifunctional electrode prepared by the preparation method according to any one of claims 1-6.

8. The application of the industrial-grade alkaline hydrogen production bifunctional electrode as described in claim 7 in water electrolysis for hydrogen production.

9. The application according to claim 8, characterized in that, The industrial-grade alkaline hydrogen production bifunctional electrode serves as the cathode and / or anode in water electrolysis for hydrogen production. The current density for hydrogen production via water electrolysis is 10-1000 mA / cm². 2 ; The electrolyte used in the electrolysis of water to produce hydrogen is an alkaline electrolyte. The alkaline electrolyte is a 1-8 mol / L KOH solution.

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