Anion exchange membrane electrolysis water / seawater hydrogen production catalyst, preparation method, electrolytic bath and electrolysis method

Abstract

The invention discloses an anion exchange membrane electrolysis water / seawater hydrogen production catalyst, a preparation method, an electrolytic bath and an electrolysis method. The preparation method of the catalyst comprises the following steps: S1, carrying out ultrasonic cleaning and vacuum drying on foamed nickel to obtain pretreated foamed nickel; s2, immersing the pretreated foamed nickel into the deposition liquid, performing deposition preparation by adopting a cathode cyclic voltammetry deposition method under a three-electrode system, taking out and cleaning the deposited foamed nickel, and performing vacuum drying to obtain nickel-cobalt-manganese hydrotalcite; s3, putting the obtained nickel-cobalt-manganese hydrotalcite into a reaction kettle filled with a selenylation solution, putting the reaction kettle into a drying oven, carrying out heat preservation reaction, naturally cooling to room temperature after the reaction is finished, washing, and carrying out vacuum drying to obtain a nickel-cobalt-manganese selenide precursor; and S4, putting the obtained nickel cobalt manganese selenide precursor into a plasma cleaning machine, and treating the front surface and the back surface with plasma to obtain the nickel cobalt manganese selenide. The catalyst not only has excellent seawater electrolysis hydrogen evolution catalytic activity, but also has excellent oxygen evolution catalytic activity.

Description

Technical Field

[0001] The invention relates to the technical field of water electrolysis catalysts, and in particular to a preparation method and application of a catalyst for producing hydrogen by electrolyzing water / seawater through an anion exchange membrane. Background Art

[0002] As environmental pollution becomes more serious, people are looking for renewable energy to replace traditional fossil energy. At the same time, hydrogen, as a green energy, has attracted widespread attention from researchers for its great advantages in renewable energy conversion and storage. Using renewable electricity to electrolyze water to produce high-purity hydrogen has become a major way to transform to carbon-neutral energy. Compared with the electrolysis of fresh water, seawater is one of the most abundant resources in the world. Seawater electrolysis has sufficient raw material supply. Energy conversion in seawater electrolysis is used in conjunction with offshore wind farms, hydropower and photovoltaic power stations. Seawater wind energy, light energy, tidal energy, etc. are stored in the form of hydrogen energy and supplied to seawater platforms, experimental bases or coastal cities, forming a "centralized wind power, photovoltaic + hydrogen energy + offshore platform + Internet of Things + coastal blockchain" smart interconnected combination network. In addition, the electrolyzer can be modularly and flexibly designed, and can produce hydrogen in a centralized manner and supply hydrogen in a regional manner, realizing the interconnection of energy networks. Therefore, hydrogen production by electrolysis of seawater is the key to achieving energy transformation with hydrogen energy as the medium, and it is also one of the main ways to produce hydrogen on a large scale in the future, providing new possibilities for large-scale, long-term storage and long-distance transportation of electricity.

[0003] The electrolysis of seawater is the same as traditional water electrolysis. The overall reaction is divided into two half reactions, including the hydrogen evolution reaction at the cathode and the oxygen evolution reaction at the anode. The seawater environment is complex, with a large number of chloride ions, which seriously corrode the catalyst electrode. In addition, during the oxygen evolution reaction of seawater electrolysis at the anode, chloride ions will compete with each other to produce hypochlorous acid, reducing the Faraday efficiency of oxygen evolution in seawater electrolysis, and thus reducing the efficiency of hydrogen production by seawater electrolysis.

[0004] In the traditional water electrolysis process, Pt-based and Ru-based materials are usually used as commercial hydrogen evolution reaction and oxygen evolution reaction catalysts. However, their high prices limit their large-scale application. Therefore, transition metal materials are usually considered as alternative materials to replace precious metal catalysts. Transition metal selenium compounds are not only abundant in resources and low in cost, but also have excellent electrocatalytic performance and long-term stability. Since the 3d orbital of selenium has an energy level close to the 3s and 3p orbitals of metals, it helps to form bonds with metal atoms and facilitate electron transfer. The incorporation of manganese and cobalt elements can improve the electrocatalytic performance of the catalyst. The incorporation of manganese can increase the electrochemical surface area and electrocatalytic stability of the catalyst. Cobalt-manganese-based catalysts have high electrocatalytic oxygen evolution activity. During the oxygen evolution process, the valence state of the metal cation increases and forms a mixed valence state, resulting in an adjustable electronic configuration of the material, which facilitates the movement of electrons and improves conductivity.

[0005] CN116377483A discloses a method for preparing a transition metal-based catalyst and a transition metal-based catalyst, wherein the method for preparing the transition metal-based catalyst comprises: (1) preparing a transition metal hydroxide or oxide by electrodeposition using a transition metal salt; (2) subjecting the transition metal hydroxide or oxide to an alkali treatment. The preparation method can regulate the morphology, crystal structure and electronic structure of the transition metal-based catalyst, thereby preparing a transition metal-based catalyst with high intrinsic activity. When the transition metal-based catalyst with high intrinsic activity is applied to hydrogen production by electrolysis of water, the efficiency of hydrogen production can be improved, the energy consumption of electrolysis can be reduced, and resources can be saved.

[0006] CN113737202A discloses a method for preparing a transition metal water electrolysis catalyst, which comprises the following steps: preparing an iron phosphide precursor: preparing a pretreated nickel foam; adding 1-butanol, a P123 surfactant, and nitric acid in a 100 mL beaker in sequence at room temperature to form a uniform solution; calcining the dried nickel foam in air for 12 hours to obtain a precursor, using NaH2PO4 as a phosphorus source, performing a low-temperature phosphating reaction, heating a tubular furnace to 350°C in an argon atmosphere, and then rapidly cooling the mixture to room temperature to obtain a sample meso-FeP / CC, which has high electrochemical activity and exhibits optimal HER catalytic activity.

[0007] When used as catalysts, transition metal materials often only have a single catalytic activity for hydrogen evolution or oxygen evolution, which results in two different cathode and anode water electrolysis catalysts having different tolerances to the electrolyte. Therefore, the preparation of bifunctional water electrolysis catalysts is of great significance.

[0008] CN111589459A discloses a bifunctional catalyst for efficient water electrolysis and its preparation method and application. The method comprises: activating a three-dimensional nanostructure template under overpotential conditions; immersing the activated three-dimensional nanostructure template in a transition metal salt solution for ion adsorption treatment, and taking it out to obtain the bifunctional catalyst for efficient water electrolysis. The bifunctional catalyst for efficient water electrolysis prepared by the method has efficient water electrolysis decomposition performance. In the hydrogen evolution reaction, the bifunctional catalyst has a high conductivity at 10 mA·cm -2 The overpotential at the current density of 10 mA cm is 139 mV. -2 The overpotential at a current density of 239 mV is 239 mV. However, this method requires the use of a three-dimensional nanostructure template, which is difficult to control and increases the experimental process and difficulty.

[0009] Therefore, it is necessary to develop low-cost electrolytic water catalysts with excellent catalytic activity and stability, which are low in cost and simple in preparation, and to turn the electrocatalytic target to abundant seawater resources to reduce freshwater pressure and environmental limitations. At the same time, the electrolysis of seawater is combined with anion exchange membrane electrolyzers to improve the stability and catalytic activity of the anion exchange membrane electrolyzer seawater electrolysis system, which is of great significance to the development of electrolysis of water / seawater hydrogen production technology. Summary of the invention

[0010] In view of this, the purpose of the present invention is to overcome the problems of high cost of existing noble metal catalysts for electrolysis of seawater and poor selectivity and insufficient stability of transition metal catalysts, and to provide a preparation method and application of an anion exchange membrane electrolysis of water / seawater hydrogen production catalyst. The anion exchange membrane electrolysis of water / seawater hydrogen production catalyst prepared by the present invention has high catalytic activity and good stability, and has low preparation cost and simple method, which is conducive to realizing industrial-scale production.

[0011] To achieve the above object, the present invention adopts the following technical solutions:

[0012] The first object of the present invention is to provide a method for preparing a catalyst for producing hydrogen by electrolysis of water / seawater using an anion exchange membrane, which comprises the following steps:

[0013] Step S1. Immersing the nickel foam in hydrochloric acid, ethanol and water in turn for ultrasonic cleaning, and vacuum drying to obtain the pretreated nickel foam;

[0014] Step S2. dissolving nickel nitrate hexahydrate, manganese sulfate monohydrate, cobalt nitrate hexahydrate and ammonium fluoride in water, stirring to obtain a deposition solution; immersing the pretreated nickel foam obtained in step S1 in the deposition solution, and preparing the deposition by cathode cyclic voltammetry deposition method under a three-electrode system, taking out the deposited nickel foam, washing it with ethanol and water, and then vacuum drying it to obtain nickel-cobalt-manganese hydrotalcite;

[0015] Step S3. dissolving the reducing agent sodium borohydride in deionized water, mixing the selenium powder therein and stirring, then adding the ethanol solution, stirring again to obtain a selenized solution, transferring the solution to a reactor, and the entire preparation process is carried out under a protective gas atmosphere; placing the nickel-cobalt-manganese hydrotalcite obtained in step S2 into a 50 mL reactor, keeping warm after the reaction, and then placing the reactor in an oven. After the reaction is completed, naturally cooling to room temperature, then washing with isopropanol and deionized water, and vacuum drying to obtain a nickel-cobalt-manganese selenide precursor;

[0016] Step S4. Put the nickel cobalt manganese selenide precursor obtained in step S3 into a plasma cleaning machine, and treat the front and back surfaces with plasma to obtain a nickel cobalt manganese selenide catalyst, which is an anion exchange membrane water / seawater electrolysis hydrogen production catalyst.

[0017] Furthermore, the size of the nickel foam in step S1 is 1-10×1-10 cm 2 , thickness is 0.02-0.2cm.

[0018] Furthermore, in step S2, the molar concentration ratio of the nickel nitrate hexahydrate, the manganese sulfate monohydrate, the cobalt nitrate hexahydrate and the ammonium fluoride is 20:(1-50):(1-50):(1-50).

[0019] Furthermore, in step S2, the cathode cyclic voltammetry deposition method uses a saturated calomel electrode as a reference electrode, a platinum sheet as a counter electrode, a voltage range of -1.2V to -0.2V, and an electrodeposition scan rate of 1-100mV·s -1 , the number of cycles is 1-50 times.

[0020] Furthermore, in step S3, the molar concentration ratio of sodium borohydride to selenium powder is (1-50):20.

[0021] Furthermore, in step S3, the first stirring time is 1-60 min, the second stirring time is 1-60 min, the insulation temperature of the reactor is 100-300° C., and the insulation time is 12-24 h; the protective gas is argon, nitrogen or argon-hydrogen mixed gas.

[0022] Furthermore, in step S4, the plasma is argon, nitrogen or argon-hydrogen mixed gas, and the plasma treatment time is 10-60 minutes.

[0023] The second object of the present invention is to provide a catalyst for producing hydrogen by electrolyzing water / seawater through an anion exchange membrane, which is prepared by the preparation method described in any of the above schemes.

[0024] The third object of the present invention is to provide an anion exchange membrane electrolyzer for electrolyzing water / seawater, which comprises a cathode, an anode and an anion exchange membrane, wherein the cathode and the anode are separated by the anion exchange membrane, and both the cathode and the anode are composed of a composite pressed sheet of the anion exchange membrane water / seawater electrolysis hydrogen production catalyst and foamed nickel as described in any of the above schemes.

[0025] The fourth object of the present invention is to provide an electrolysis method of the anion exchange membrane electrolyzer for electrolyzing water / seawater, which adopts a double water inlet method on both sides of the anode and cathode to circulate the solution and fully electrolyze water / seawater to produce hydrogen under different electrolyte conditions.

[0026] Furthermore, the dual water inlet mode on both sides of the anode and cathode is that the flow rate of the solution at the anode side water inlet is 100-500mL·min -1 , the solution flow rate at the cathode side inlet is 0.1-100mL·min -1 , the double water inlet on both sides of the anode and cathode is from the lower pipe, and the upper pipe is for water and gas mixing;

[0027] Furthermore, the different electrolyte conditions are 1.0 mol·L -1 KOH, 1.0 mol·L -1 KOH+0.5mol·L -1 NaCl, 1.0 mol·L -1 KOH+seawater and seawater.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The anion exchange membrane electrolysis water / seawater hydrogen production catalyst of the present invention forms a network-like pore structure based on the nickel-cobalt-manganese hydrotalcite layer structure, which increases the specific surface area and provides more catalytic active sites. After plasma treatment, the hydrophilicity and gas repellency of the catalyst surface are increased, making it easy to adsorb electrolytes and quickly release bubbles, significantly improving the reaction kinetics.

[0030] (2) The anion exchange membrane electrolysis water / seawater hydrogen production catalyst of the present invention undergoes surface selenium reduction and rebonding with the metal during the hydrogen evolution process, which greatly improves the hydrogen evolution catalytic performance and stability of the catalyst. During the oxygen evolution oxidation process, surface oxidation reconstruction occurs, and Se will be precipitated in large quantities and oxidized to SeO4 2- , electrostatically adsorbed on the catalyst surface, and at the same time, manganese on the catalyst surface will be oxidized into Mn3O4, forming a double barrier layer of Mn-O and Se-O, reducing the interference of chloride ions in the process of electrolysis of seawater for oxygen evolution and enhancing the selectivity of oxygen evolution.

[0031] (3) The anion exchange membrane water / seawater hydrogen production catalyst of the present invention has excellent electrochemical catalytic activity through the synergistic effect between ternary transition metals. The catalyst not only has excellent catalytic activity for hydrogen evolution by electrolysis of seawater. In alkaline seawater, the HER current density is 100 mA cm -2 The lower overpotential is only 233.4 mV, and it also has excellent oxygen evolution catalytic activity, with an OER current density of 100 mA cm -2 The lower overpotential is 344.7mV. The current density of the full electrolysis of alkaline seawater is 10mA·cm -2 The lower overpotential is 1.41mV, and the electrolysis can be stable for 200h. The anion exchange membrane electrolysis of water / seawater hydrogen production catalyst can achieve the effect of a self-supporting electrode material. The electrolysis of water / seawater anion exchange membrane electrolyzer is assembled, and the anode and cathode are used to feed water at 500mA·cm -2 The voltage required under the current density is only 1.94V, and it can run stably for 200 hours, which is suitable for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1is the X-ray electron diffraction pattern of the NiCoMnSe water / seawater electrolysis catalyst in Example 1;

[0033] Figure 2 (a) Scanning electron microscopy image of the NiCoMnSe water / seawater electrolysis catalyst in Example 1; (b) Transmission electron microscopy image;

[0034] Figure 3 The nickel cobalt manganese selenide electrolytic water / seawater catalyst in Example 1-5 electrolyzed 1.0 mol·L -1 Polarization curve of hydrogen evolution reaction of KOH solution;

[0035] Figure 4 The NiCoMnSe electrolytic water / seawater catalyst in Example 1 electrolyzes 1.0 mol·L -1 KOH, 1.0 mol·L -1 KOH+0.5mol·L -1 NaCl and 1.0 mol·L -1 Polarization curve of hydrogen and oxygen evolution reaction of KOH+seawater solution;

[0036] Figure 5 The NiCoMnSe water / seawater electrolysis catalyst in Example 1 was used as the anode and cathode to fully electrolyze 1.0 mol·L -1 (a) Polarization curve of KOH+seawater solution; (b) 500 mA·cm -2 Current density chronopotentiometry curve;

[0037] Figure 6 A schematic diagram of the structure of the nickel cobalt manganese selenide water / seawater electrolysis catalyst and the pretreated nickel foam composite tablets in Example 6, which are assembled into a cathode and an anode and are assembled into an anion exchange membrane electrolyzer;

[0038] Figure 7 The nickel-cobalt-manganese selenide water / seawater electrolysis catalyst in Example 6 was used as the anode and cathode to assemble an anion exchange membrane electrolyzer, and 1 mol·L -1 KOH and 1.0 mol·L -1 Polarization curve of KOH+seawater solution;

[0039] Figure 8 The nickel cobalt manganese selenide water / seawater electrolysis catalyst in Example 6 was used as the anode and cathode to assemble an anion exchange membrane electrolyzer. -1 500 mA cm in KOH solution -2 Current density full electrolysis chronopotentiometry curve. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

[0041] Example 1

[0042] This embodiment provides a method for preparing a NiCoMnSe water / seawater electrolysis catalyst, and the specific steps are as follows:

[0043] Step S1. Pre-treat the commercially available nickel foam: Cut the purchased nickel foam with a thickness of 0.1 cm into 2.0×2.0 cm 2 , and then soaked in 1 mol·L -1 The pretreated nickel foam was obtained by ultrasonic treatment in hydrochloric acid solution, ethanol solution and deionized water for 30 min and then vacuum dried to remove the oxide layer on the surface of the nickel foam.

[0044] Step S2. Dissolve nickel nitrate hexahydrate, manganese sulfate monohydrate, cobalt nitrate hexahydrate and ammonium fluoride in a molar ratio of 8 mmol:4 mmol:4 mmol:8 mmol in deionized water, and stir for 30 minutes to obtain a uniform deposition solution containing metal nickel, cobalt and manganese sources; immerse the nickel foam obtained in step S1 in the deposition solution, and prepare and deposit by cathode cyclic voltammetry deposition method in a three-electrode system with a saturated calomel electrode as a reference electrode and a platinum sheet as a counter electrode, with a voltage range of -1.2V to -0.2V and an electrodeposition scan rate of 2mV·s -1 The number of cycles is 7. The nickel foam after deposition is taken out, washed with ethanol and deionized water, and then placed in a vacuum drying oven at 60°C for 6 hours to obtain nickel-cobalt-manganese hydrotalcite.

[0045] Step S3. 65 mg of reducing agent sodium borohydride is dissolved in 5 mL of deionized water, and then 59 mg of selenium powder is mixed therein and stirred for 5 minutes, and then the ethanol solution is quickly added. After stirring for 10 minutes, the solution becomes milky white and is quickly transferred to a 50 mL reactor. The preparation of the selenized solution is carried out under a nitrogen atmosphere throughout the process; the nickel cobalt manganese hydrotalcite obtained in step S2 is placed in the 50 mL reactor described above, and then the 50 mL reactor is placed in an oven and kept warm at 140° C. for 12 hours. After the reaction is completed, it is naturally cooled to room temperature, and then washed with isopropanol and deionized water, and vacuum dried at 60° C. for 6 hours to obtain a nickel cobalt manganese selenide precursor.

[0046] Step S4. Place the nickel cobalt manganese selenide precursor obtained in step S3 into a plasma cleaning machine, and use argon gas to treat the front and back surfaces for 15 minutes each to obtain a NiCoMnSe water / seawater electrolysis catalyst.

[0047] Example 2

[0048] This embodiment provides a method for preparing a NiCo5Mn1Se water / seawater electrolysis catalyst, and the specific steps are as follows:

[0049] Step S1. Pre-treat the commercially available nickel foam: cut the nickel foam with a thickness of 0.1 cm into 2.0×2.0 cm 2 , and then soaked in 1 mol·L -1 The pretreated nickel foam was obtained by ultrasonic treatment in hydrochloric acid solution, ethanol solution and deionized water for 30 min and then vacuum dried to remove the oxide layer on the surface of the nickel foam.

[0050] Step S2. Dissolve nickel nitrate hexahydrate, manganese sulfate monohydrate, cobalt nitrate hexahydrate and ammonium fluoride in a molar ratio of 8 mmol:1.33 mmol:6.67 mmol:8 mmol in deionized water, and stir for 30 minutes to obtain a uniform deposition solution containing metal nickel, cobalt and manganese sources; immerse the nickel foam obtained in step S1 in the deposition solution, and prepare and deposit by cathode cyclic voltammetry deposition method in a three-electrode system with a saturated calomel electrode as a reference electrode and a platinum sheet as a counter electrode, with a voltage range of -1.2 V to -0.2 V and an electrodeposition scan rate of 2 mV·s -1 The number of cycles is 7. The nickel foam after deposition is taken out, washed with ethanol and deionized water, and then placed in a vacuum drying oven at 60°C for 6 hours to obtain nickel-cobalt-manganese hydrotalcite.

[0051] Step S3. 65 mg of reducing agent sodium borohydride is dissolved in 5 mL of deionized water, and then 59 mg of selenium powder is mixed therein and stirred for 5 minutes, and then the ethanol solution is quickly added. After stirring for 10 minutes, the solution becomes milky white and is quickly transferred to a 50 mL reactor. The preparation of the selenized solution is carried out under a nitrogen atmosphere throughout the process; the nickel cobalt manganese hydrotalcite obtained in step S2 is placed in the 50 mL reactor described above, and then the 50 mL reactor is placed in an oven and kept warm at 140° C. for 12 hours. After the reaction is completed, it is naturally cooled to room temperature, and then washed with isopropanol and deionized water, and vacuum dried at 60° C. for 6 hours to obtain a nickel cobalt manganese selenide precursor.

[0052] Step S4. Place the nickel cobalt manganese selenide precursor obtained in step S3 into a plasma cleaning machine, and use argon gas to treat the front and back surfaces for 15 minutes each to obtain a NiCo5Mn1Se water / seawater electrolysis catalyst.

[0053] Example 3

[0054] This embodiment provides a method for preparing a NiCo3Mn1Se water / seawater electrolysis catalyst, and the specific steps are as follows:

[0055] Step S1. Pre-treat the commercially available nickel foam: cut the nickel foam with a thickness of 0.1 cm into 2.0×2.0 cm 2 , and then soaked in 1 mol·L -1 The pretreated nickel foam was obtained by ultrasonic treatment in hydrochloric acid solution, ethanol solution and deionized water for 30 min and then vacuum dried to remove the oxide layer on the surface of the nickel foam.

[0056] Step S2. Dissolve nickel nitrate hexahydrate, manganese sulfate monohydrate, cobalt nitrate hexahydrate and ammonium fluoride in a molar ratio of 8 mmol: 2.67 mmol: 5.33 mmol: 8 mmol in deionized water, and stir for 30 minutes to obtain a uniform deposition solution containing metal nickel, cobalt and manganese sources; immerse the nickel foam obtained in step S1 in the deposition solution, and prepare and deposit by cathode cyclic voltammetry deposition method in a three-electrode system with a saturated calomel electrode as a reference electrode and a platinum sheet as a counter electrode, with a voltage range of -1.2 V to -0.2 V and an electrodeposition scan rate of 2 mV·s -1 The number of cycles is 7. The nickel foam after deposition is taken out, washed with ethanol and deionized water, and then placed in a vacuum drying oven at 60°C for 6 hours to obtain nickel-cobalt-manganese hydrotalcite.

[0057] Step S3. 65 mg of reducing agent sodium borohydride is dissolved in 5 mL of deionized water, and then 59 mg of selenium powder is mixed therein and stirred for 5 minutes, and then the ethanol solution is quickly added. After stirring for 10 minutes, the solution becomes milky white and is quickly transferred to a 50 mL reactor. The preparation of the selenized solution is carried out under a nitrogen atmosphere throughout the process; the nickel cobalt manganese hydrotalcite obtained in step S2 is placed in the 50 mL reactor described above, and then the 50 mL reactor is placed in an oven and kept warm at 140° C. for 12 hours. After the reaction is completed, it is naturally cooled to room temperature, and then washed with isopropanol and deionized water, and vacuum dried at 60° C. for 6 hours to obtain a nickel cobalt manganese selenide precursor.

[0058] Step S4. Place the nickel cobalt manganese selenide precursor obtained in step S3 into a plasma cleaning machine, and use argon gas to treat the front and back surfaces for 15 minutes each to obtain a NiCo3Mn1Se anion exchange membrane water / seawater electrolysis catalyst.

[0059] Example 4

[0060] This embodiment provides a method for preparing a NiCo1Mn3Se water / seawater electrolysis catalyst, and the specific steps are as follows:

[0061] Step S1. Pre-treat the commercially available nickel foam: cut the nickel foam with a thickness of 0.1 cm into 2.0×2.0 cm 2 , and then soaked in 1 mol·L -1The pretreated nickel foam was obtained by ultrasonic treatment in hydrochloric acid solution, ethanol solution and deionized water for 30 min and then vacuum dried to remove the oxide layer on the surface of the nickel foam.

[0062] Step S2. Dissolve nickel nitrate hexahydrate, manganese sulfate monohydrate, cobalt nitrate hexahydrate and ammonium fluoride in a molar ratio of 8 mmol: 5.33 mmol: 2.67 mmol: 8 mmol in deionized water, and stir for 30 minutes to obtain a uniform deposition solution containing metal nickel, cobalt and manganese sources; immerse the nickel foam obtained in step S1 in the deposition solution, and prepare and deposit by cathode cyclic voltammetry deposition method in a three-electrode system with a saturated calomel electrode as a reference electrode and a platinum sheet as a counter electrode, with a voltage range of -1.2 V to -0.2 V and an electrodeposition scan rate of 2 mV·s -1 The number of cycles is 7. The nickel foam after deposition is taken out, washed with ethanol and deionized water, and then placed in a vacuum drying oven at 60°C for 6 hours to obtain nickel-cobalt-manganese hydrotalcite.

[0063] Step S3. 65 mg of reducing agent sodium borohydride is dissolved in 5 mL of deionized water, and then 59 mg of selenium powder is mixed therein and stirred for 5 minutes, and then the ethanol solution is quickly added. After stirring for 10 minutes, the solution becomes milky white and is quickly transferred to a 50 mL reactor. The preparation of the selenized solution is carried out under a nitrogen atmosphere throughout the process; the nickel cobalt manganese hydrotalcite obtained in step S2 is placed in the 50 mL reactor described above, and then the 50 mL reactor is placed in an oven and kept warm at 140° C. for 12 hours. After the reaction is completed, it is naturally cooled to room temperature, and then washed with isopropanol and deionized water, and vacuum dried at 60° C. for 6 hours to obtain a nickel cobalt manganese selenide precursor.

[0064] Step S4. Place the nickel cobalt manganese selenide precursor obtained in step S3 into a plasma cleaning machine, and use argon gas to treat the front and back surfaces for 15 minutes each to obtain a NiCo1Mn3Se water / seawater electrolysis catalyst.

[0065] Example 5

[0066] This embodiment provides a method for preparing a NiCo1Mn5Se water / seawater electrolysis catalyst, and the specific steps are as follows:

[0067] Step S1. Pre-treat the commercially available nickel foam: cut the nickel foam with a thickness of 0.1 cm into 2.0×2.0 cm 2 , and then soaked in 1 mol·L -1 The pretreated nickel foam was obtained by ultrasonic treatment in hydrochloric acid solution, ethanol solution and deionized water for 30 min and then vacuum dried to remove the oxide layer on the surface of the nickel foam.

[0068] Step S2. Dissolve nickel nitrate hexahydrate, manganese sulfate monohydrate, cobalt nitrate hexahydrate and ammonium fluoride in a molar ratio of 8 mmol: 6.67 mmol: 1.33 mmol: 8 mmol in deionized water, and stir for 30 minutes to obtain a uniform deposition solution containing metal nickel, cobalt and manganese sources; immerse the nickel foam obtained in step S1 in the deposition solution, and prepare and deposit by cathode cyclic voltammetry deposition method in a three-electrode system with a saturated calomel electrode as a reference electrode and a platinum sheet as a counter electrode, with a voltage range of -1.2 V to -0.2 V and an electrodeposition scan rate of 2 mV·s -1 The number of cycles is 7. The nickel foam after deposition is taken out, washed with ethanol and deionized water, and then placed in a vacuum drying oven at 60°C for 6 hours to obtain nickel-cobalt-manganese hydrotalcite.

[0069] Step S3. 65 mg of reducing agent sodium borohydride is dissolved in 5 mL of deionized water, and then 59 mg of selenium powder is mixed therein and stirred for 5 minutes, and then the ethanol solution is quickly added. After stirring for 10 minutes, the solution becomes milky white and is quickly transferred to a 50 mL reactor. The preparation of the selenized solution is carried out under a nitrogen atmosphere throughout the process; the nickel cobalt manganese hydrotalcite obtained in step S2 is placed in the 50 mL reactor described above, and then the 50 mL reactor is placed in an oven and kept warm at 140° C. for 12 hours. After the reaction is completed, it is naturally cooled to room temperature, and then washed with isopropanol and deionized water, and vacuum dried at 60° C. for 6 hours to obtain a nickel cobalt manganese selenide precursor.

[0070] Step S4. Place the nickel cobalt manganese selenide precursor obtained in step S3 into a plasma cleaning machine, and use argon gas to treat the front and back surfaces for 15 minutes each to obtain a NiCo1Mn5Se water / seawater electrolysis catalyst.

[0071] Example 6

[0072] This embodiment provides an electrolysis method of an anion exchange membrane electrolyzer for electrolyzing water / seawater, and the specific steps are as follows:

[0073] 1. Preparation of nickel-cobalt-manganese selenide catalyst for electrolysis of water / seawater:

[0074] Step S1. Pre-treat the commercially available nickel foam: cut the nickel foam with a thickness of 0.1 cm into 4.5×4.5 cm 2 , and then soaked in 1 mol·L -1 The pretreated nickel foam was obtained by ultrasonic treatment in hydrochloric acid solution, ethanol solution and deionized water for 30 min and then vacuum dried to remove the oxide layer on the surface of the nickel foam.

[0075] Step S2. Dissolve nickel nitrate hexahydrate, manganese sulfate monohydrate, cobalt nitrate hexahydrate and ammonium fluoride in a molar ratio of 16 mmol: 8 mmol: 8 mmol: 16 mmol in 200 mL of water, and stir for 30 min to obtain a uniform deposition solution containing metal nickel, cobalt and manganese sources; immerse the nickel foam obtained in step S1 in the deposition solution, and prepare and deposit by cathode cyclic voltammetry deposition method in a three-electrode system with a saturated calomel electrode as a reference electrode and a platinum sheet as a counter electrode, with a voltage range of -1.2 V to -0.2 V and an electrodeposition scan rate of 2 mV·s -1 The number of cycles is 7. The nickel foam after deposition is taken out, washed with ethanol and water, and then placed in a vacuum drying oven at 60°C for 6 hours to obtain nickel-cobalt-manganese hydrotalcite.

[0076] Step S3. 260 mg of reducing agent sodium borohydride is dissolved in 10 mL of deionized water, and then 236 mg of selenium powder is mixed therein and stirred for 5 minutes, and then 90 mL of anhydrous ethanol solution is quickly added. After stirring for another 10 minutes, the solution becomes milky white and is quickly transferred to a 100 mL reactor. The preparation of the selenized solution is carried out under a nitrogen atmosphere throughout the process; the nickel-cobalt-manganese hydrotalcite obtained in step S2 is placed in the 100 mL reactor described above, and then the 100 mL reactor is placed in an oven and kept warm at 140° C. for 12 hours. After the reaction is completed, it is naturally cooled to room temperature, and then washed with isopropanol and deionized water, and vacuum dried at 60° C. for 6 hours to obtain a nickel-cobalt-manganese selenide precursor.

[0077] Step S4. Place the nickel cobalt manganese selenide precursor obtained in step S3 into a plasma cleaning machine, and use argon gas to treat the front and back surfaces for 15 minutes each to obtain a nickel cobalt manganese selenide water / seawater electrolysis catalyst.

[0078] 2. Preparation of anion exchange membrane electrolyzer for electrolyzing water / seawater:

[0079] Step S5. The nickel-cobalt-manganese selenide water / seawater electrolysis catalyst obtained in step S4 is pressed into a composite sheet with pretreated nickel foam to form a cathode electrode and an anode electrode; the cathode 1 and the anode 2 are separated by an anion exchange membrane 3, see Figure 6 shown.

[0080] 3. Electrolysis of water / seawater anion exchange membrane electrolyzer:

[0081] S6. The electrolyte condition is 1.0 mol·L -1 KOH and 1.0 mol·L -1 KOH+seawater, using dual water inlet on both the anode and cathode sides, the flow rate of the anode water inlet solution is 350mL min -1 The flow rate of the solution at the cathode inlet is 10 mL min -1The double water inlets on both sides of the anode and cathode are from the lower pipe 4, and the upper pipe 5 is used to discharge water and gas mixture.

[0082] Structural testing:

[0083] The crystal structure of Example 1 was analyzed by X-ray electron diffractometer. Figure 1 As shown, the diffraction angles 2θ at 28.29, 33.00, 44.55, 50.08 and 69.25 correspond to the (100), (101), (102), (110), (201) and (202) crystal planes in the standard PDF card 70-2851 of NiCoSe2, and there are slight offsets, indicating that the catalyst grown on nickel foam is mainly composed of manganese-doped Ni CoSe2.

[0084] The morphology of the NiCoMnSe water / seawater electrolysis catalyst prepared in Example 1 was observed by scanning electron microscopy and transmission electron microscopy. Figure 2 As shown, the catalyst is a nanosheet layered structure loaded with nickel cobalt manganese selenide particles grown in situ on a three-dimensional network of nickel foam. This structure increases the specific surface area, exposes more active sites, increases electron transport, and improves electrocatalytic activity.

[0085] Performance Test:

[0086] 1. Electrochemical performance test:

[0087] (1) Add 1 mol·L -1 KOH, filter out the white precipitate, and obtain a clear alkaline seawater electrolyte with a concentration of 1.0 mol·L -1 KOH+seawater solution;

[0088] (2) The electrochemical workstation used was CHI 660e (Shanghai Chenhua Instrument Co., Ltd.). In a three-electrode system, a carbon rod was used as the counter electrode, saturated calomel was used as the reference electrode, Example 1-5 was used as the working electrode, and the electrolyte was 1.0 mol·L -1 KOH, 1.0 mol·L -1 KOH+0.5mol·L -1 NaCl and 1.0 mol·L -1 KOH+seawater, firstly activated by cyclic voltammetry, then the electrochemical performance of hydrogen and oxygen evolution was tested by linear sweep voltammetry, with a scan rate of 2mV·s -1 .

[0089] Figure 3 The nickel cobalt manganese selenide water / seawater electrolysis catalyst of Example 1-5 is 1.0 mol·L -1Linear voltammetric curves of hydrogen evolution reaction in KOH and NiCoMnSe water / seawater electrolysis catalyst at 100 mA cm -2 The lowest overpotential for hydrogen evolution reaction is obtained at the current density, and the required overpotential is 202.4 mV.

[0090] Figure 4 The mixed linear voltammetric curves of the NiCoMnSe water / seawater electrolysis catalyst in Example 1 for hydrogen and oxygen evolution reactions in three electrolytes are shown in Figure 1. Compared with 1.0 mol·L -1 KOH, at 1.0 mol·L -1 The hydrogen and oxygen evolution performance of NiCoMnSe electrolysis water / seawater catalyst in KOH+seawater was slightly attenuated. -2 The overpotential required for the current density is 233.4 mV, and the overpotential required for the oxygen evolution process is 100 mA cm -2 The overpotential required at the current density is 344.7mV.

[0091] Table 1. Examples 1-5 Different addition amounts of nickel cobalt manganese selenide electrolysis water / seawater catalyst electrolysis 1.0 mol·L -1 Comparison of overpotentials of KOH hydrogen evolution reaction

[0092] Catalytic materials <![CDATA[10mAcm -2 Overpotential η 10 (mV)]]> <![CDATA[100mAcm -2 Overpotential η 100 (mV)]]> <![CDATA[NiCo5Mn1Se]]> 187.9 322.5 <![CDATA[NiCo3Mn1Se]]> 163.4 329.6 NiCoMnSe 92.5 202.4 <![CDATA[NiCo1Mn3Se]]> 178.4 346.3 <![CDATA[NiCo1Mn5Se]]> 174.1 343.2

[0093] Table 2. Comparison of overpotentials of hydrogen and oxygen evolution reactions in three different electrolytes using NiCoMnSe water / seawater electrolysis catalysts in Example 1

[0094]

[0095]

[0096] 2. Fully electrolytic alkaline seawater test:

[0097] In the electrolysis of alkaline seawater test, a two-electrode system was used, and the NiCoMnSe water / seawater electrolysis catalyst of Example 1 was used as both the cathode and the anode. The full electrolysis test was performed by linear sweep voltammetry at a scan rate of 2 mV·s -1 , the stability of the material was tested using full electrolysis chronopotentiometric testing.

[0098] Figure 5 (a) NiCoMnSe electrolysis of water / seawater catalyst in Example 1 with double electrode for full electrolysis of 1.0 mol·L -1 KOH+seawater linear voltammetric curve, at 10 mA cm -2 The required potential is only 1.41V at the current density.

[0099] Figure 5 (b) NiCoMnSe electrolysis of water / seawater catalyst in Example 1 with double electrode for full electrolysis of 1.0 mol·L -1 KOH+seawater chronopotentiometry curve at 10 mA·cm -2 It can run stably for 200h at the current density.

[0100] 3. Anion exchange membrane electrolyzer performance test:

[0101] An AutoLab electrochemical workstation was used to assemble an anion exchange membrane electrolyzer into a two-electrode system using the nickel cobalt manganese selenide water / seawater electrolysis catalyst of Example 6 as the anode and cathode. Full electrolysis testing was performed by linear sweep voltammetry at 60°C with water entering both sides of the anode and cathode at a scan rate of 2 mV s -1 , full electrolysis stability test was performed using chronopotentiometry.

[0102] Figure 6 This is a schematic diagram of the structural composition of the anion exchange membrane electrolyzer assembled with the nickel cobalt manganese selenide water / seawater electrolysis catalyst as the anode and cathode in Example 6, which includes the nickel cobalt manganese selenide water / seawater electrolysis catalyst, anion exchange membrane, a sealing ring, a conductive electrode plate, a plastic gasket and an outer metal plate.

[0103] Figure 7 The electrolytic water / seawater anion exchange membrane electrolyzer of Example 6 is 1 mol·L -1 KOH and 1.0 mol·L -1 The full electrolysis polarization curve in KOH+seawater solution is -1 500 mA cm in KOH solution -2 The required potential is only 1.94V at a current density of 1.0 mol·L -1 500 mA cm in KOH+seawater solution -2 There is no significant decay in the required potential when the current density increases.

[0104] Figure 8 The electrolytic water / seawater anion exchange membrane electrolyzer of Example 6 was 1 mol·L at 60°C. -1 The full electrolysis chronopotentiometry curve in KOH solution at 500 mA cm -2 It can run stably for 200h at the current density.

[0105] It should be noted that electrolyzed water generally refers to electrolyzed fresh water. Therefore, the "electrolyzed water / seawater" in the specification refers to electrolyzed fresh water or seawater.

[0106] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made to the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a catalyst for producing hydrogen by electrolysis of water / seawater using an anion exchange membrane. It is characterized in that The following steps are involved: Step S1. Immersing the nickel foam in hydrochloric acid, ethanol and water in turn for ultrasonic cleaning, and vacuum drying to obtain the pretreated nickel foam; Step S2. dissolving nickel nitrate hexahydrate, manganese sulfate monohydrate, cobalt nitrate hexahydrate and ammonium fluoride in water, stirring to obtain a deposition solution; immersing the pretreated nickel foam obtained in step S1 in the deposition solution, and preparing the deposition by cathode cyclic voltammetry deposition method under a three-electrode system, taking out the deposited nickel foam, washing it with ethanol and water, and then vacuum drying it to obtain nickel-cobalt-manganese hydrotalcite; Step S3. dissolving the reducing agent sodium borohydride in deionized water, mixing the selenium powder therein and stirring, then adding the ethanol solution, stirring again to obtain a selenized solution, transferring the solution to a reactor, and the entire preparation process is carried out under a protective gas atmosphere; placing the nickel-cobalt-manganese hydrotalcite obtained in step S2 into a 50 mL reactor, and then placing the reactor in an oven for heat preservation and reaction, cooling naturally to room temperature after the reaction is completed, and then washing with isopropanol and deionized water, and vacuum drying to obtain a nickel-cobalt-manganese selenide precursor; Step S4. Put the nickel cobalt manganese selenide precursor obtained in step S3 into a plasma cleaning machine, and treat the front and back surfaces with plasma to obtain a nickel cobalt manganese selenide catalyst, which is an anion exchange membrane water / seawater electrolysis hydrogen production catalyst.

2. The method for preparing the anion exchange membrane water / seawater hydrogen production catalyst according to claim 1, It is characterized in that The size of the nickel foam in step S1 is 1-10×1-10 cm 2 , thickness is 0.02-0.2cm.

3. The method for preparing the anion exchange membrane water / seawater hydrogen production catalyst according to claim 1, It is characterized in that In step S2, the molar concentration ratio of the nickel nitrate hexahydrate, manganese sulfate monohydrate, cobalt nitrate hexahydrate and ammonium fluoride is 20:(1-50):(1-50):(1-50).

4. The method for preparing the anion exchange membrane water / seawater hydrogen production catalyst according to claim 1, It is characterized in that In step S2, the cathode cyclic voltammetry deposition method uses a saturated calomel electrode as a reference electrode, a platinum sheet as a counter electrode, a voltage range of -1.2V to -0.2V, and an electrodeposition scan rate of 1-100mV·s -1 , the number of cycles is 1-50 times.

5. The method for preparing the anion exchange membrane water / seawater hydrogen production catalyst according to claim 1, It is characterized in that In step S3, the molar concentration ratio of sodium borohydride to selenium powder is (1-50):

20.

6. The method for preparing the anion exchange membrane water / seawater hydrogen production catalyst according to claim 1, It is characterized in that In step S3, the first stirring time is 1-60 min, the second stirring time is 1-60 min, the insulation temperature of the reactor is 100-300° C., and the insulation time is 12-24 h; the protective gas is argon, nitrogen or argon-hydrogen mixed gas.

7. The method for preparing the anion exchange membrane water / seawater hydrogen production catalyst according to claim 1, It is characterized in that In step S4, the plasma is argon, nitrogen or argon-hydrogen mixed gas, and the plasma treatment time is 10-60 minutes.

8. A catalyst for hydrogen production by electrolysis of water / seawater using an anion exchange membrane. It is characterized in that The invention is prepared by the preparation method described in any one of claims 1 to 7.

9. An anion exchange membrane electrolyzer for electrolyzing water / seawater, It is characterized in that It comprises a cathode, an anode and an anion exchange membrane, wherein the cathode and the anode are separated by the anion exchange membrane, and both the cathode and the anode are composed of the anion exchange membrane water / seawater electrolysis hydrogen production catalyst and foamed nickel composite tablets as claimed in claim 8.

10. An electrolysis method of the water / seawater anion exchange membrane electrolyzer according to claim 9, It is characterized in that The solution is circulated by double water inlet on both sides of the anode and cathode, and hydrogen is produced by full electrolysis of water / seawater under different electrolyte conditions.

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