Nano-alloy catalyst for anion exchange membrane electrolyzed water and preparation method of membrane electrode of nano-alloy catalyst

Abstract

The invention discloses a nano-alloy catalyst for anion exchange membrane electrolyzed water and a preparation method of a membrane electrode of the nano-alloy catalyst, when any one of manganese salt, cerium salt, chromium salt, cobalt salt, lanthanum salt, ruthenium salt and iridium salt is not added, NiFe binary alloy powder is obtained, the content of Ni is 90%-100%, and the content of Fe is 0%-10%; when any one of manganese salt, cerium salt, chromium salt, cobalt salt, lanthanum salt, ruthenium salt and iridium salt is added, NiFe ternary alloy powder is obtained, the content of Ni is 76%-96%, the content of Fe is 4%, and the content of the third element is 0%-20%. The nano-alloy catalyst material for anion exchange membrane water electrolysis prepared according to the invention is good in corrosion resistance and high in stability, the total water splitting efficiency is further improved, the synthesis method is simple, the used metal salt is low in cost, the metal salt can be uniformly loaded on a substrate carrier through spraying, and industrial application of total water splitting under high current density is easy to realize.

Description

Technical Field

[0001] The invention relates to the field of hydrogen production by alkaline water electrolysis, and more specifically to a nano alloy catalyst for anion exchange membrane water electrolysis and a preparation method of a membrane electrode thereof. Background Art

[0002] The electrocatalytic oxygen evolution reaction (OXYGRE) in alkaline media is a key step in the industrial electrolysis of water to produce hydrogen. Seeking efficient, stable and low-cost oxygen evolution electrocatalysts has been a research hotspot in the field of electrochemistry in recent years.

[0003] The AEM water electrolyzer consists of an anion exchange membrane and two transition metal catalyst-based electrodes. Distilled water or low-concentration alkaline solutions can be used as electrolytes in AEM instead of highly concentrated potassium hydroxide solutions. The AEM approach combines the advantages of PEM and alkaline electrolysis. When searching for the keyword "anion exchange membrane water electrolysis" on the scientific website, there are few complete studies on AEM water electrolysis, which shows that AEM electrolysis technology is still in the early development stage and needs further research. Coordinated research on AEM electrolysis is currently needed to improve power efficiency, membrane stability and ionic conductivity, reduce the total stack cost, and integrate catalysts into AEM systems. One of the main advantages of AEM electrolysis is the ability to use platinum-based metal (PGM)-free electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in separate reaction chambers. This reduces the capital cost of AEM water electrolysis. The current challenge of AEM catalyst development is to optimize the chemical composition, stability, and overall activity in the AEM system. Compared with precious metal-based catalysts, platinum-free metal electrocatalysts generally have relatively low mass specific activity, which leads to a large catalyst loading on the membrane electrode assembly (MEA) and causes large ohmic resistance losses.

[0004] Therefore, a nano-alloy electrocatalyst that is free of precious metals and has excellent water electrolysis catalytic ability and stability has great potential.

[0005] Explanation of terms: alkaline water electrolysis, anode catalyst, oxygen evolution reaction, overpotential, anion exchange membrane

[0006] Alkaline electrolysis of water: Alkaline electrolysis of water refers to the process of producing hydrogen by electrolyzing water in an alkaline electrolyte environment. The electrolyte is generally a 30% mass concentration KOH solution.

[0007] Anode catalyst: Anode catalyst is a catalyst that can promote electrochemical reactions. It can accelerate the oxygen evolution reaction at the anode, thereby improving the efficiency and speed of the electrochemical reaction.

[0008] Oxygen evolution reaction: Oxygen evolution reaction (OER) is a half-reaction in the water electrolysis reaction, involving a multi-electron transfer process and slow kinetic reaction, which is a key factor restricting the efficiency of the entire water electrolysis device.

[0009] Overpotential: Also known as superpotential or overpotential, it refers to the part of the actual voltage required to reach a certain current density in the electrocatalytic reaction that exceeds the theoretical voltage. The working potential in the actual reaction often needs to overcome the obstacles of the kinetic process and thus show a value higher than the equilibrium potential. The voltage exceeding the theoretical value is called overpotential, which is mainly used to overcome other resistances such as activation resistance and charge transfer resistance.

[0010] Anion exchange membrane: Anion exchange membrane is a type of polymer membrane that contains alkaline active groups and has selective permeability to anions, also known as ion selective permeability membrane. Anion exchange membrane consists of three parts: the polymer main chain with fixed groups, namely the polymer matrix (also known as the base membrane), the positively charged active groups (i.e. cations), and the anions that can move freely on the active groups. Summary of the invention

[0011] The purpose of the present invention is to provide a nano alloy catalyst for anion exchange membrane water electrolysis and a method for preparing the membrane electrode thereof, thereby solving the problem in the prior art of lacking a nano alloy electrocatalyst that is free of precious metals and has excellent water electrolysis catalytic ability and stability.

[0012] In order to solve the above problems, the present invention adopts the following technical solutions:

[0013] According to the first aspect of the present invention, a method for preparing a nano alloy catalyst for anion exchange membrane water electrolysis is provided, comprising the following steps: S1: dispersing a plurality of metal salts in deionized water in a certain proportion, ultrasonically treating, and obtaining a uniformly dispersed mixture solution. The metal salts include nickel salts and iron salts, and selectively adding any one of manganese salts, cerium salts, chromium salts, cobalt salts, lanthanum salts, ruthenium salts, and iridium salts; S2: adding NaOH solution dropwise to the above solution to adjust the pH of the solution to 11; S3: placing the suspension obtained in step S2 into a centrifuge tube, centrifuging repeatedly for multiple times, pouring out the supernatant after each centrifugation, re-adding deionized water, and finally collecting the precipitate; S4: taking out the precipitate, placing it into a ball mill, adding anhydrous ethanol, ball milling for a period of time, sucking it into a beaker with a dropper, and drying; S5: taking out the dried powder, placing it in a porcelain boat, placing it in a tubular furnace, heating it for a period of time under a hydrogen atmosphere, keeping it warm for a period of time at a specific temperature, and waiting for the tubular furnace to cool down naturally; S6 : Put the powder after hydrogen reduction in step S5 into a ball mill, add anhydrous ethanol, ball mill for a period of time, suck the ball milled solution into a beaker with a dropper, and dry it at a certain temperature to obtain a nano alloy catalyst for anion exchange membrane water electrolysis. When any one of manganese salt, cerium salt, chromium salt, cobalt salt, lanthanum salt, ruthenium salt, and iridium salt is not added, a NiFe binary alloy powder is obtained, and the Ni content is 90% to 100%, and the Fe content is 0% to 10%; when any one of manganese salt, cerium salt, chromium salt, cobalt salt, lanthanum salt, ruthenium salt, and iridium salt is added, a NiFe ternary alloy powder is obtained, and the Ni content is 76% to 96%, the Fe content is 4%, and the content of the third element is 0% to 20%.

[0014] Preferably, in step S1, the iron salt is iron nitrate, the nickel salt is nickel chloride or nickel nitrate, the cerium salt is cerium chloride or cerium nitrate, the chromium salt is chromium chloride or chromium nitrate, the manganese salt is manganese chloride, the cobalt salt is cobalt nitrate, the lanthanum salt is lanthanum nitrate, the ruthenium salt is ruthenium chloride, and the iridium salt is iridium chloride.

[0015] Preferably, the ultrasonic conditions in step S1 are: ultrasonic power: 50-100%, ultrasonic duration: 10-30 min, and ultrasonic frequency 70-99 kHz.

[0016] Preferably, in step S2, the concentration of the NaOH solution is 1 mol / L.

[0017] Preferably, in step S3, the centrifugal speed is 7000-9000 rpm, the single centrifugal time is 5-15 min, and the number of centrifugation times is 3-5 times.

[0018] Preferably, in step S4, the ball milling speed is 300-400 rpm, the drying temperature is 60-90° C., and the drying time is 2-10 h.

[0019] Preferably, in step S5, the reduction temperature is 600-800°C and the reduction time is 2-10 hours. The function of this step is to reduce the precursor to metal. The hydrogen reduction temperature is the alloy phase reduction temperature of Ni. If it is too low, it is not easy to reduce. If it is too high, the particles will agglomerate, become larger and harder.

[0020] Preferably, in step S6, the ball milling speed is 300-400 rpm, the drying temperature is 60-90° C., and the drying time is 2-10 hours. The function of ball milling in this step is to reduce the precursor particles.

[0021] It should be understood that the ball milling speed in steps S4 and S6 is within the range required for preparing nanoparticles. If it is too small, it is difficult to form nano-scale particles, and if it is too large, the energy is too high and the catalyst surface is prone to excessive oxidation.

[0022] According to a second aspect of the present invention, a nano alloy catalyst for anion exchange membrane water electrolysis prepared according to the above preparation method is provided. When any one of manganese salt, cerium salt, chromium salt, cobalt salt, lanthanum salt, ruthenium salt and iridium salt is not added, a NiFe binary alloy powder is obtained, and the Ni content is 90% to 100%, and the Fe content is 0% to 10%; when any one of manganese salt, cerium salt, chromium salt, cobalt salt, lanthanum salt, ruthenium salt and iridium salt is added, a NiFe ternary alloy powder is obtained, and the Ni content is 76% to 96%, the Fe content is 4%, and the content of the third element is 0% to 20%, and the third element is any one of manganese, cerium, chromium, cobalt, lanthanum, ruthenium and iridium.

[0023] According to a third aspect of the present invention, a method for preparing a membrane electrode is provided, comprising the following steps: S7: placing zirconium beads in a glass bottle, weighing a certain amount of nano-alloy catalyst, placing it in a glass bottle, adding deionized water, an organic solvent and a binder, and rolling and grinding for a period of time after ultrasonic dispersion to obtain a catalyst slurry; S8: pouring the prepared slurry into a spray gun, and spraying it evenly on different gas diffusion layer carriers or anion exchange membranes on a heating table, and pressing the gas diffusion layer, the catalyst layer, and the anion exchange membrane together to assemble into a membrane electrode.

[0024] Preferably, in step S7, the volume ratio of deionized water to organic solvent is 1:9, the content of binder is 10% to 20% of the total amount of binder and catalyst, and the rolling time is 10 to 30 hours; in step S8, the temperature of the heating table is 60 to 80°C, and the gas diffusion layer carrier includes nickel foam, carbon paper or carbon cloth.

[0025] It should be understood that in step S7, water and alcohol are dispersants, and a suitable water-to-alcohol ratio is conducive to the dispersion of the powder. Too low a water content is not conducive to the dispersion of the alloy, and too high a water content is not conducive to drying during spraying. A large amount of binder affects the performance, and a small amount affects the stability. Too short a rolling time is not conducive to dispersion, and too long a rolling time is prone to deterioration of the binder.

[0026] According to a fourth aspect of the present invention, there is provided a membrane electrode produced according to the above-mentioned production method.

[0027] Among Ni-based materials, researchers usually tend to synthesize Ni-based oxides or hydroxides because of their higher electrochemical activity, and rarely use alloy materials directly as anodes. Because the active substance in the OER process is mainly Ni-OOH, Ni-based hydroxides are more likely to produce Ni-OOH in comparison, but Ni-based hydroxides have poor conductivity. The alloy material prepared by the present invention solves the problem of conductivity very well, and the inevitable presence of an oxide layer on the surface is also conducive to the generation of Ni-OOH. Among Ni-based materials, researchers also usually tend to synthesize materials with high Fe content because the Fe element can reduce the oxidation potential of Ni, but the Fe content is too high and is easily dissolved during the reaction, resulting in poor stability. Therefore, the present invention controls the Fe content to 4%, which also has good electrochemical properties.

[0028] According to the preparation method of a nano alloy catalyst for anion exchange membrane water electrolysis provided by the present invention, among the multiple metal salts in step S1, nickel salt and iron salt are essential components, Ni element is used as a substrate, and the Fe element is introduced to regulate, and the best NiFe ratio is obtained by testing the binary alloy, which is Ni: 96%, Fe: 4%. At the same time, the present invention further introduces a third element on the basis of the binary alloy to improve the performance, and the proportion of the third element is: 0%-20%.

[0029] The material of the present invention is an anode material used in anion exchange membrane water electrolysis. The multi-metal nano alloy anode catalyst prepared by the method of the present invention is in the form of nano microspheres, has a core-shell structure, low iron content and other characteristics, and can be used as an anode material in alkaline water electrolysis. When the solution pH is 14 and the current density is 10mA / cm 2 Under the condition of low current density, the overpotential is 220-350mV, and it still has a low overpotential under high current density. It can be prepared as a membrane electrode and assembled into an electrolyzer, which can greatly reduce the energy consumption of hydrogen production in alkaline electrolyzers. When the voltage is only 1.9V, the industrial relevant current density can reach 10000A·m -2 , and can operate stably in 60℃, 1M potassium hydroxide electrolyte.

[0030] Compared with the prior art, the nano alloy catalyst for alkaline water electrolysis and the preparation method thereof described in the present invention have the following advantages:

[0031] 1) The nano alloy catalyst material for anion exchange membrane water electrolysis prepared by the present invention has a small particle size, many surface active sites, and excellent conductivity, thereby improving the overall water splitting efficiency;

[0032] 2) The nano alloy catalyst material for anion exchange membrane water electrolysis prepared by the present invention has an iron content range of 0%-10% for the binary alloy and 4% for the ternary alloy, while most of the Ni:Fe ratios in the prior art are 4:1 or 5:1, i.e. (15%-20%) or higher. Therefore, the nano alloy catalyst material prepared by the present invention has good corrosion resistance and stability, thereby improving the overall water splitting efficiency;

[0033] 3) The nano alloy catalyst material for anion exchange membrane water electrolysis prepared by the present invention has a simple synthesis method, and the metal salt used is low in cost. It can be evenly loaded on the substrate carrier by spraying, and is easy to achieve industrial application of full water splitting under high current density. After the process of the catalyst of the present invention is amplified and optimized, it can be used in industrial anion exchange membrane electrolyzers. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 , Figure 2 The morphology of alloy powder particles under transmission electron microscopy shows that the size of the alloy particles is 20-50nm;

[0035] Figure 3 , Figure 4 This is the morphology of powder slurry sprayed on carbon paper;

[0036] Figure 5 The XRD images of nano alloy catalyst materials under different Fe contents prove that the materials prepared under different iron contents are all Ni-based metal alloys;

[0037] Figure 6 The LSV performance images of nano alloy catalyst materials under different Fe content conditions;

[0038] Figure 7 , Figure 8 , Fig. 9 The changes in the performance of the nano-alloy catalyst material brought about by adjusting the Ce, Cr, and Mn contents are shown respectively;

[0039] Figure 10-13 These are the lsv performance diagrams of nano alloy catalyst materials introduced with La, Co, Ru and Ir respectively;

[0040] Fig.14 NiFe 4％The stability of the material was verified by three-electrode test at a current density of 100 mA / cm;

[0041] Fig.15 To make NiFe 4％ LSV curve of the electrolytic cell tested at 60°C after being assembled with commercial Pt / C as the anode. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional operations in the art, or according to the experimental methods recommended by the instrument and equipment manufacturers. The reagents and materials used in the examples can be obtained from commercial sources unless otherwise specified.

[0043] Embodiment 1:

[0044] Taking the preparation of binary alloy NiFe powder as an example, the specific testing method of the present invention is described.

[0045] The specific synthesis scheme process is as follows:

[0046] Step 1), disperse the required amount of ferric nitrate and nickel chloride in a certain proportion in 50 ml of deionized water, and perform ultrasonic treatment to obtain a uniformly dispersed mixture solution.

[0047] Wherein, in the mixture, the content of Fe is 0% to 10%.

[0048] Step 2), add the 1 mol / L NaOH solution prepared in advance dropwise to the solution of step 1), and adjust the pH of the solution to ≈11 while stirring continuously with ultrasound.

[0049] Step 3), after the suspension generated in step 2) is placed in a centrifuge tube, it is placed in a centrifuge and centrifuged repeatedly for 3 times, after each centrifugation, the supernatant is poured out, deionized water is added again, and finally the precipitate is collected.

[0050] Step 4), after taking out the precipitate collected in step 3), put it into a ball mill, add anhydrous ethanol, and ball mill at 350 rpm for 4 hours. The ball-milled solution is pipetted into a beaker and dried at 70°C.

[0051] Step 5), take out the dried powder described in step 4) and place it in a porcelain boat; put the porcelain boat containing the powder into a tubular furnace, heat it for 60 minutes under a hydrogen atmosphere (nitrogen as a protective gas), and then keep it at 600°C for 2 hours for reduction, and wait for the tubular furnace to cool down naturally.

[0052] Step 6), the powder reduced with hydrogen in step 5) is placed in a ball mill, anhydrous ethanol is added, and the ball milling is performed at 350 rpm for 4 hours. The ball milled solution is pipetted into a beaker and dried at 70° C. to obtain a binary alloy NiFe powder.

[0053] The morphology of alloy powder particles under transmission electron microscopy is shown in Figure 2. Figure 1 , Figure 2 As shown, it can be seen that the size of the alloy particles is 20-50nm.

[0054] The performance changes of nano alloy catalyst materials brought about by adjusting the Fe content are as follows: Figure 6 As shown in the figure, compared with pure nickel, the addition of Fe improves its electrochemical performance, and the performance is best when the Fe content is 4%.

[0055] Embodiment 2:

[0056] Taking the preparation of ternary alloy NiFeCe powder as an example, the specific testing method of the present invention is described.

[0057] The specific synthesis scheme process is as follows:

[0058] Step 1), disperse the required amount of ferric nitrate, nickel chloride and cerium chloride in a certain proportion in 50 ml of deionized water, and perform ultrasonic treatment to obtain a uniformly dispersed mixture solution.

[0059] Among them, in the mixture, the preset molar ratio of NiFe element content is Ni: 96%, Fe: 4%; the preset molar ratio of NiFe element to Ce element content is NiFe 4％ : 80% ~ 98%, Ce: 2% ~ 20%.

[0060] Step 2), add the 1 mol / L NaOH solution prepared in advance dropwise to the solution of step 1), and adjust the pH of the solution to ≈11 while stirring continuously with ultrasound.

[0061] Step 3), after the suspension generated in step 2) is placed in a centrifuge tube, it is placed in a centrifuge and centrifuged repeatedly for 5 times, after each centrifugation, the supernatant is poured out, deionized water is added again, and finally the precipitate is collected.

[0062] Step 4), after taking out the precipitate collected in step 3), put it into a ball mill, add anhydrous ethanol, and ball mill at 380 rpm for 4 hours. The ball-milled solution is pipetted into a beaker and dried at 70°C.

[0063] Step 5), take out the dried powder described in step 4) and place it in a porcelain boat; put the porcelain boat containing the powder into a tubular furnace, heat it for 60 minutes under a hydrogen atmosphere (nitrogen as a protective gas), and then keep it at 600°C for 5 hours for reduction, and wait for the tubular furnace to cool down naturally.

[0064] Step 6), the powder reduced with hydrogen in step 5) is placed in a ball mill, anhydrous ethanol is added, and the ball mill is performed at 380 rpm for 4 h. The ball milled solution is pipetted into a beaker and dried at 70°C.

[0065] The performance changes of nano alloy catalyst materials brought about by adjusting Ce content are as follows: Figure 7 As shown in the figure, with the increase of Ce element, the performance first increases and then decreases. This experiment only tests NiFeCr materials with a Ce content of less than 20%. The best performance is 10% Ce content.

[0066] Embodiment 3:

[0067] Taking the preparation of ternary alloy NiFeCr powder as an example, the specific testing method of the present invention is described.

[0068] The specific synthesis scheme process is as follows:

[0069] Step 1), disperse the required amount of ferric nitrate, nickel chloride and chromium chloride in a certain proportion in 50 ml of deionized water, and perform ultrasonic treatment to obtain a uniformly dispersed mixture solution.

[0070] Wherein, in the mixture, the preset molar ratio of NiFe element content is Ni: 76% to 94%, Fe: 4%; Cr: 2% to 20%.

[0071] Step 2), add the 1 mol / L NaOH solution prepared in advance dropwise to the solution of step 1), and adjust the pH of the solution to ≈11 while stirring continuously with ultrasound.

[0072] Step 3), after the suspension generated in step 2) is placed in a centrifuge tube, it is placed in a centrifuge and centrifuged repeatedly for 5 times, after each centrifugation, the supernatant is poured out, deionized water is added again, and finally the precipitate is collected.

[0073] Step 4), after taking out the precipitate collected in step 3), put it into a ball mill, add anhydrous ethanol, and ball mill it at 400 rpm for 8 hours. The solution after ball milling is sucked into a beaker with a dropper and dried at 80°C.

[0074] Step 5), take out the dried powder described in step 4) and place it in a porcelain boat; put the porcelain boat containing the powder into a tubular furnace, heat it for 100 minutes under a hydrogen atmosphere (nitrogen as a protective gas), and then keep it at 800°C for 4 hours for reduction, and wait for the tubular furnace to cool down naturally.

[0075] Step 6), the powder reduced with hydrogen in step 5) is placed in a ball mill, anhydrous ethanol is added, and the ball mill is performed at 400 rpm for 8 h. The ball milled solution is pipetted into a beaker and dried at 80°C.

[0076] The performance changes of nano alloy catalyst materials brought about by adjusting the Cr content are as follows: Figure 8 As shown in the figure, the performance gradually increases with the increase of Cr element. This experiment only tests NiFeCr materials with a Cr content of less than 20%. The best performance is 20%.

[0077] Embodiment 4:

[0078] Taking the preparation of ternary alloy NiFeMn powder as an example, the specific testing method of the present invention is described.

[0079] The specific synthesis scheme process is as follows:

[0080] Step 1), disperse the required amount of ferric nitrate, nickel chloride and manganese chloride in a certain proportion in 50 ml of deionized water, and perform ultrasonic treatment to obtain a uniformly dispersed mixture solution.

[0081] Wherein, in the mixture, the preset molar ratio of NiFe element content is Ni: 76% to 94%, Fe: 4%; Mn: 2% to 20%.

[0082] Step 2), add the 1 mol / L NaOH solution prepared in advance dropwise to the solution of step 1), and adjust the pH of the solution to ≈11 while stirring continuously with ultrasound.

[0083] Step 3), after the suspension generated in step 2) is placed in a centrifuge tube, it is placed in a centrifuge and centrifuged repeatedly for 4 times. After each centrifugation, the supernatant is poured out, deionized water is added again, and finally the precipitate is collected.

[0084] Step 4), after taking out the precipitate collected in step 3), put it into a ball mill, add anhydrous ethanol, and ball mill it at 350 rpm for 5 hours. The solution after ball milling is pipetted into a beaker and dried at 60°C.

[0085] Step 5), take out the dried powder described in step 4) and place it in a porcelain boat; put the porcelain boat containing the powder into a tubular furnace, heat it for 70 minutes under a hydrogen atmosphere (nitrogen as a protective gas), and then keep it at 700°C for 4 hours for reduction, and wait for the tubular furnace to cool down naturally.

[0086] Step 6), the powder reduced with hydrogen in step 5) is placed in a ball mill, anhydrous ethanol is added, and the ball mill is performed at 350 rpm for 5 h. The ball milled solution is pipetted into a beaker and dried at 60°C.

[0087] The performance changes of nano alloy catalyst materials brought about by adjusting the Mn content are as follows: Fig. 9As shown, Mn element is added. This experiment only tests NiFeCr materials with a content of less than 20%. The best performance Mn content is 8%.

[0088] Embodiment 5:

[0089] Taking the preparation of ternary alloy NiFeRu powder as an example, the specific testing method of the present invention is described.

[0090] The specific synthesis scheme process is as follows:

[0091] Step 1), disperse the required amount of ferric nitrate, nickel chloride and ruthenium chloride in a certain proportion in 50 ml of deionized water, and perform ultrasonic treatment to obtain a uniformly dispersed mixture solution.

[0092] Wherein, in the mixture, the preset molar ratio of NiFe element content is Ni: 76% to 94%, Fe: 4%; Ru: 10%.

[0093] Step 2), add the 1 mol / L NaOH solution prepared in advance dropwise to the solution of step 1), and adjust the pH of the solution to ≈11 while stirring continuously with ultrasound.

[0094] Step 3), after the suspension generated in step 2) is placed in a centrifuge tube, it is placed in a centrifuge and centrifuged repeatedly for 5 times, after each centrifugation, the supernatant is poured out, deionized water is added again, and finally the precipitate is collected.

[0095] Step 4), after taking out the precipitate collected in step 3), put it into a ball mill, add anhydrous ethanol, and ball mill at 400 rpm for 6 hours. The ball-milled solution is pipetted into a beaker and dried at 60°C.

[0096] Step 5), take out the dried powder described in step 4) and place it in a porcelain boat; put the porcelain boat containing the powder into a tubular furnace, heat it for 50 minutes under a hydrogen atmosphere (nitrogen as a protective gas), and then keep it at 600°C for 5 hours for reduction, and wait for the tubular furnace to cool down naturally.

[0097] Step 6), the powder reduced with hydrogen in step 5) is placed in a ball mill, anhydrous ethanol is added, and the ball mill is performed at 400 rpm for 6 hours. The ball milled solution is pipetted into a beaker and dried at 60°C.

[0098] In addition to the introduction of ruthenium, this embodiment also conducted experiments on the introduction of La, Co, and Ir. The LSV performance diagrams of the nano alloy catalyst materials introduced with La, Co, Ru, and Ir are shown in FIG. Figure 10-13 shown.

[0099] Embodiment 6:

[0100] Taking the preparation of binary alloy NiFe powder film electrode as an example, the specific testing method of the present invention is described.

[0101] Step 1), zirconium beads were placed in a small glass bottle, 50 mg of NiFe powder catalyst was weighed and placed in a small glass bottle, 500 μL of deionized water, 4.5 mL of isopropanol and 100 μL of FAA-3-SOLUT-10 were added, and after ultrasonication for 15 min, rolling milling was performed for 12 h to obtain a catalyst slurry.

[0102] Step 2), pour the prepared slurry into a spray gun, and evenly spray it on the anion exchange membrane FAA-3-pk-75 on a 70°C heating table, and press the gas diffusion layer, catalyst layer, and anion exchange membrane together to assemble a membrane electrode.

[0103] The morphology of powder slurry sprayed on carbon paper is as follows Figure 3 , Figure 4 shown.

[0104] Embodiment 7:

[0105] Taking the preparation of ternary alloy NiFeMn powder film electrode as an example, the specific testing method of the present invention is described.

[0106] Step 1), zirconium beads were placed in a small glass bottle, 30 mg of NiFeMn powder catalyst was weighed and placed in a small glass bottle, 300 μL of deionized water, 2.7 mL of isopropanol and 60 μL of FAA-3-SOLUT-10 were added, ultrasonicated for 15 min, and then rolled for 12 h to obtain a catalyst slurry.

[0107] Step 2), pour the prepared slurry into a spray gun, spray it evenly on the carbon paper on a 60°C heating table, and press the gas diffusion layer, catalyst layer, and anion exchange membrane together to assemble a membrane electrode.

[0108] Embodiment 8:

[0109] Taking the preparation of ternary alloy NiFeCe powder film electrode as an example, the specific testing method of the present invention is described.

[0110] Step 1), zirconium beads were placed in a small glass bottle, 50 mg of NiFeCe powder catalyst was weighed and placed in a small glass bottle, 500 μL of deionized water, 4.5 mL of isopropanol and 100 μL of FAA-3-SOLUT-10 were added, and after ultrasonication for 15 min, rolling milling was performed for 24 h to obtain a catalyst slurry.

[0111] Step 2), pour the prepared slurry into a spray gun, spray it evenly on the nickel foam on a 70° C. heating table, and press the gas diffusion layer, catalyst layer, and anion exchange membrane together to assemble a membrane electrode.

[0112] Fig.14 NiFe 4％ The stability of the material was demonstrated by three-electrode test at a current density of 100 mA / cm.

[0113] Fig.15 To make NiFe 4％ As an anode, the LSV curve tested at 60°C after being assembled into an electrolytic cell with commercial Pt / C proves the excellent performance of the material as an anode assembled in the electrolytic cell.

[0114] The metal elements selected in the present invention when preparing alloy nanomaterials are Fe, Ni, Mn, Co, Ce, La, Cr, Ru, Ir, etc. The iron-nickel binary metal catalyst already has great potential to become a catalyst for complete water splitting, and the introduction of manganese, cerium and chromium elements further improves the catalytic activity and stability. The synthesized catalyst is a nano core-shell structure with excellent OER performance, which can greatly reduce the energy consumption of hydrogen production in alkaline electrolyzers and still have a low overpotential at high current density. When the voltage is only 1.9V, the industrial-related current density can reach 10000A·m -2 , and it operates stably in 1M potassium hydroxide electrolyte at 60°C.

[0115] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiments of the present invention can also be modified in various ways. All simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A method for preparing a nano alloy catalyst for anion exchange membrane water electrolysis, characterized in that: The following steps are involved: S1: Dispersing a plurality of metal salts in a certain proportion in deionized water, and ultrasonically treating the mixture to obtain a uniformly dispersed mixture solution. The metal salts include nickel salts and iron salts, and selectively adding any one of manganese salts, cerium salts, chromium salts, cobalt salts, lanthanum salts, ruthenium salts, and iridium salts; S2: Add NaOH solution dropwise to the above solution to adjust the pH of the solution to 11; S3: After placing the suspension obtained in step S2 into a centrifuge tube, repeatedly centrifuge for multiple times, pouring out the supernatant after each centrifugation, re-adding deionized water, and finally collecting the precipitate; S4: taking out the precipitate, putting it into a ball mill, adding anhydrous ethanol, ball milling for a period of time, sucking it into a beaker with a dropper, and drying it; S5: taking out the dried powder, placing it in a porcelain boat, and putting it into a tube furnace. In a hydrogen atmosphere, heating it for a period of time, then keeping it at a specific temperature for a period of time, and then waiting for the tube furnace to cool down naturally. S6: putting the powder reduced by hydrogen in step S5 into a ball mill, adding anhydrous ethanol, and ball milling for a period of time, sucking the ball-milled solution into a beaker with a dropper, and drying at a certain temperature to obtain a nano alloy catalyst for anion exchange membrane water electrolysis; Wherein, when any one of manganese salt, cerium salt, chromium salt, cobalt salt, lanthanum salt, ruthenium salt and iridium salt is not added, a NiFe binary alloy powder is obtained, wherein the content of Ni is 90% to 100% and the content of Fe is 0% to 10%; When any one of manganese salt, cerium salt, chromium salt, cobalt salt, lanthanum salt, ruthenium salt and iridium salt is added, a NiFe ternary alloy powder is obtained, in which the Ni content is 76% to 96%, the Fe content is 4%, and the content of the third element is 0% to 20%.

2. The preparation method according to claim 1, characterized in that: In the step S1, the iron salt is iron nitrate, the nickel salt is nickel chloride or nickel nitrate, the cerium salt is cerium chloride or cerium nitrate, the chromium salt is chromium chloride or chromium nitrate, the manganese salt is manganese chloride, the cobalt salt is cobalt nitrate, the lanthanum salt is lanthanum nitrate, the ruthenium salt is ruthenium chloride, and the iridium salt is iridium chloride.

3. The preparation method according to claim 1, characterized in that: In step S3, the centrifugal speed is 7000-9000 rpm, the single centrifugal time is 5-15 min, and the number of centrifugation is 3-5 times.

4. The preparation method according to claim 1, characterized in that: In the step S4, the ball milling speed is 300-400 rpm, the drying temperature is 60-90° C., and the drying time is 2-10 h.

5. The preparation method according to claim 1, characterized in that: In step S5, the reduction temperature is 600-800° C., and the reduction time is 2-10 hours.

6. The preparation method according to claim 1, characterized in that: In the step S6, the ball milling speed is 300-400 rpm, the drying temperature is 60-90° C., and the drying time is 2-10 h.

7. A nano alloy catalyst for anion exchange membrane water electrolysis prepared according to the preparation method according to any one of claims 1 to 6, wherein: When any one of manganese salt, cerium salt, chromium salt, cobalt salt, lanthanum salt, ruthenium salt and iridium salt is not added, a NiFe binary alloy powder is obtained, and the Ni content is 90% to 100%, and the Fe content is 0% to 10%; when any one of manganese salt, cerium salt, chromium salt, cobalt salt, lanthanum salt, ruthenium salt and iridium salt is added, a NiFe ternary alloy powder is obtained, and the Ni content is 76% to 96%, the Fe content is 4%, and the content of the third element is 0% to 20%, and the third element is any one of manganese, cerium, chromium, cobalt, lanthanum, ruthenium and iridium.

8. A method for preparing a membrane electrode, characterized in that: The following steps are involved: S7: Put zirconium beads in a glass bottle, weigh a certain amount of the nano alloy catalyst for anion exchange membrane water electrolysis prepared by the preparation method according to any one of claims 1 to 6 or the nano alloy catalyst for anion exchange membrane water electrolysis according to claim 7, put it in a glass bottle, add deionized water, an organic solvent and a binder, and roll grind for a period of time after ultrasonic dispersion to obtain a catalyst slurry; S8: Pour the prepared slurry into a spray gun, spray it evenly on different gas diffusion layer carriers or anion exchange membranes on a heating table, and press the gas diffusion layer, catalyst layer, and anion exchange membrane together to assemble a membrane electrode.

9. The preparation method according to claim 8, characterized in that: In the step S7, the volume ratio of deionized water to organic solvent is 1:9, the content of binder is 10% to 20% of the total amount of binder and catalyst, and the rolling time is 10 to 30 hours; in the step S8, the temperature of the heating table is 60 to 80° C., and the gas diffusion layer carrier includes foamed nickel, carbon paper or carbon cloth.

10. A membrane electrode prepared according to the preparation method according to any one of claims 8 to 9.

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