Method for preparing iron-doped cobalt-nickel sulfide catalyst from waste spaceflight magnetic material

Abstract

The invention discloses a method for preparing an iron-doped cobalt-nickel sulfide catalyst by using a waste spaceflight magnetic material. The method realizes efficient recovery of metal cobalt and nickel in the waste spaceflight magnetic material (the recovery rate gt; 95%), and the nanoscale iron-doped cobalt-nickel sulfide catalyst is prepared. The method comprises the following specific steps: grinding the waste spaceflight magnetic material and an additive M, roasting in an electric furnace at 500-550 DEG C for 6-8 hours, and cooling to obtain a roasted product A; adding the roasted product A into a deep-eutectic solvent with the temperature of 80-120 DEG C, stirring and leaching to obtain a leaching solution B; reducing the temperature of the leachate B to 50-60 DEG C, adding thioacetamide, stirring and dissolving, and then adding potassium hydroxide to obtain a solution D; transferring the solution D into a reaction container at the temperature of 95-120 DEG C, stirring and reacting for 10-15 hours, separating, washing and drying to obtain the iron-doped cobalt-nickel sulfide electrolyzed water catalyst nano powder. The technological process is simple and efficient, large-scale implementation convenience is achieved, safety is outstanding, and the risk of secondary pollution is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of material preparation, and particularly to a method for preparing an iron-doped cobalt-nickel sulfide catalyst from waste aerospace magnetic materials. Background Art

[0002] With the rapid development of the aerospace industry, the reasonable treatment and reuse of waste aerospace magnetic materials, as an important type of industrial waste, have become increasingly prominent. Waste aerospace magnetic materials refer to the magnetic materials discarded during the development, use, or maintenance of spacecraft. Aerospace magnetic materials usually include magnetic alloys, magnets, and permanent magnetic materials, etc. These materials contain a large amount of precious metal elements such as cobalt and nickel, and have high recycling value.

[0003] As an emerging green solvent, deep eutectic solvents have characteristics such as high conductivity, good degradability, and non-toxicity, and are widely used in various fields such as biocatalytic conversion, inorganic material synthesis, and electrochemistry. As an efficient synthesis technology, the ionothermal method provides precise control for the preparation process of inorganic materials. This method utilizes the properties of ionic liquids and opens up a new path for the design and production of controllable nanomaterials. By using the deep eutectic solvent leaching method and the ionothermal reduction method, the high-valence elements in waste aerospace magnetic materials are converted into an iron-doped cobalt-nickel sulfide electrocatalytic material for water electrolysis. By optimizing the process parameters of the leaching process and ionothermal reduction, it is expected that a bifunctional material with excellent performance for hydrogen evolution and oxygen evolution in water electrolysis can be prepared.

[0004] An electrocatalyst is a special substance that can increase the reaction rate of a chemical reaction while not changing the overall energy change of the reaction. It does not directly participate in the reaction process, so its mass and chemical properties remain the same before and after the reaction. The basic requirement for a catalyst is that it should be able to significantly adjust the reaction rate without affecting the final equilibrium state of the reaction. So far, platinum-based materials are still the most efficient electrocatalysts for the hydrogen evolution reaction, while ruthenium / iridium-based materials show the best electrocatalytic performance in the oxygen evolution reaction. However, these rare and precious metal electrocatalysts are not only costly but also challenging to store. Therefore, developing an efficient electrocatalytic material that not only has high energy conversion efficiency but also low catalytic overpotential is of crucial significance for promoting the hydrogen evolution and oxygen evolution reactions in water electrolysis. Summary of the Invention

[0005] Aiming at the above deficiencies existing in the prior art, the purpose of the present invention is to solve the problems of high cost and difficult storage of existing catalysts, and to provide a method for preparing an iron-doped cobalt-nickel sulfide catalyst from waste aerospace magnetic materials.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for preparing an iron-doped cobalt-nickel sulfide catalyst from waste aerospace magnetic materials, which is characterized by including the following steps:

[0008] S1: Pretreat the waste aerospace magnetic materials, mix them with additive M, grind them, transfer them to an electric furnace at 500-550 °C for roasting for 6-8 hours, cool them to room temperature with the furnace, take out the roasted product, obtain roasted material A, and seal and store it for later use;

[0009] S2: Add roasted material A to a eutectic ionic liquid at 80-120 °C and stir for leaching to obtain leaching solution B;

[0010] S3: Lower the temperature of leaching solution B to 50-60 °C, then add thioacetamide to leaching solution B and stir to dissolve to obtain solution C;

[0011] S4: Add potassium hydroxide to solution C and stir to dissolve to obtain solution D;

[0012] S5: Transfer solution D to a quartz reaction vessel at 95-120 °C and stir for reaction for 10-15 hours. After the reaction, separate out the black powder product;

[0013] S6: Rinse the product 3 times with pure water - absolute ethanol - pure water in a cycle, and vacuum-dry the washed product to obtain the iron-doped cobalt-nickel sulfide electrolyzed water catalyst nano-powder.

[0014] Optionally, in step S1, the cobalt content in the waste aerospace magnetic materials is 5-40%, the nickel content is 1-25%, and the iron content is 4-40%.

[0015] Optionally, in step S1, the pretreatment method of the waste aerospace magnetic materials is to crush them to pass through 200-300 meshes, soak them in a 20-40% calcium chloride solution for 10-15 minutes, rinse them with clean water, then soak them in a 10-15% sodium hydroxide solution for 10-15 minutes, rinse them with clean water 2-3 times, and dry them.

[0016] Optionally, in step S1, additive M is a mixture of sodium chloride and sodium sulfate. The addition amount of sodium chloride is 0.2-0.5%, the addition amount of sodium sulfate is 1-2%, and the mass ratio of sodium chloride to sodium sulfate is 1:(4-5).

[0017] Optionally, in step S2, the eutectic ionic liquid is an organic solvent obtained by mixing choline chloride and ethylene glycol at 40-50 °C according to a molar ratio of 1:(2-4).

[0018] Optionally, in step S1, the particle size of roasted material A is 50-60 microns.

[0019] Optionally, in step S2, the addition amount of A in the eutectic ionic liquid is 10 to 300 grams per liter, the stirring speed is 300 to 500 revolutions per minute, and the leaching time is 6 to 12 hours.

[0020] Optionally, in step S3, thioacetamide is an anhydrous reagent with a dosage of 0.5 to 2 grams per liter; in step S4, the dosage of potassium hydroxide is 5 to 15 grams per liter, and the molar ratio of the addition amount of thioacetamide to the cobalt content in the leaching solution B is (2 to 3):1, and the molar ratio of the addition amount of potassium hydroxide to the cobalt content in the leaching solution B is (2 to 3):1.

[0021] Preferably, after the solution is added to the quartz reaction vessel, the rotation speed of the oil bath is controlled at 300 revolutions per minute. First, stir for 10 minutes at a temperature of 100 °C, and then stop stirring and let it stand for reaction for 15 hours.

[0022] Based on the above method, the present invention also provides an iron-doped cobalt-nickel sulfide catalyst, which is characterized in that it is prepared by the method for preparing an iron-doped cobalt-nickel sulfide catalyst from waste aerospace magnetic materials described above.

[0023] In addition, the present invention also provides an application of the iron-doped cobalt-nickel sulfide catalyst described above as an electrocatalyst in alkaline water electrolysis.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. The present invention has the advantages of simple preparation method, easy operation, and high safety. The eutectic ionic liquid used has good solubility and can selectively dissolve valuable elements in waste aerospace magnetic materials, enabling cobalt and other valuable elements to be released into the solution in ionic form, achieving preliminary separation from other impurities; the eutectic ionic liquid can adsorb or chemically react on the surface of the iron-doped cobalt-nickel sulfide electrocatalyst for water electrolysis, modify its surface, change the surface electronic structure and chemical properties, improve the adsorption and activation ability of the electrocatalyst to reactants, and thus enhance the performance of the electrocatalyst; during the preparation and subsequent treatment processes, a protective film can be formed on the surface of the iron-doped cobalt-nickel sulfide electrocatalyst particles to prevent cobalt from being oxidized, and at the same time, it can also inhibit the agglomeration of particles, maintaining the high dispersion and stability of the electrocatalyst; as a reaction medium, the eutectic ionic liquid can provide a unique microenvironment for the chemical reaction of preparing the iron-doped cobalt-nickel sulfide catalyst, affecting the kinetic and thermodynamic processes of the reaction, promoting the progress of the reaction, and improving the reaction efficiency and yield.

[0026] 2. Deep eutectic solvents can selectively leach valuable elements from waste aerospace magnetic materials. By innovatively utilizing the selective dissolution ability of DES for cobalt oxide and nickel oxide (dissolution rate > 95%), it hardly dissolves gangue components such as Al2O3, SiO2, CaO, and MgO, and the dissolution rate of FeO x impurities is less than 0.5%, achieving targeted dissolution of valuable elements and the effect of intrinsically suppressing impurities in the leaching process. DES is used to selectively leach the calcined material of waste aerospace magnetic materials, and nano iron-doped cobalt-nickel sulfide is directly prepared by ionic thermal sulfidation in the leaching solution. By regulating the ionic thermal reaction, the doping introduction of a small amount of iron elements can also be controlled to improve the performance of the catalyst for electrolyzing water.

[0027] 3. The calcined material of waste aerospace magnetic materials is selectively leached by DES. Compared with the multi-step processes (process flow > 10 processes) of traditional pyrometallurgy or hydrometallurgical extraction, this technology can reduce 3-5 impurity removal units and shorten the conversion path by more than 60%. Nano iron-doped cobalt-nickel sulfide is prepared by direct ionic thermal sulfidation in the leaching solution, and electrolysis water catalysts are manufactured using waste resources, which can not only significantly reduce energy consumption and reduce waste residue emissions, but also greatly improve the utilization rate of waste resources. This method has both environmental protection value and practical significance, providing important support for the efficient utilization of resources and sustainable development. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, obtaining other drawings based on these drawings still belongs to the scope of the present invention.

[0029] Figure 1 It is a synthesis schematic diagram of preparing an iron-doped cobalt-nickel sulfide catalyst in Example 1.

[0030] Figure 2 It is an XRD diagram of the iron-doped cobalt-nickel sulfide catalyst prepared in Example 1.

[0031] Figure 3 It is an SEM diagram of the iron-doped cobalt-nickel sulfide catalyst prepared in Example 1.

[0032] Figure 4 It is an EDS diagram of the iron-doped cobalt-nickel sulfide catalyst prepared in Example 1.

[0033] Figure 5 It is an LSV performance diagram of the overall water splitting of the iron-doped cobalt-nickel sulfide catalyst prepared in Example 1. Detailed Embodiments

[0034] The present invention provides a method for preparing an iron-doped cobalt-nickel sulfide catalyst from waste aerospace magnetic materials. Its general synthesis process is as Figure 1 shown, including the following steps:

[0035] S1: Pretreat the waste aerospace magnetic materials, mix them with additive M, grind them, transfer them to an electric furnace at 500 - 550 °C for roasting for 6 - 8 hours, cool them with the furnace to room temperature, take out the roasted product, obtain a roasted material, and seal and store it for later use;

[0036] S2: Prepare a deep eutectic solvent by mixing choline chloride and ethylene glycol at a molar ratio of 1:2; add the roasted material to the deep eutectic ionic liquid at 90 - 120 °C, with a stirring speed of 300 - 500 revolutions per minute, and stir and leach for 6 - 12 hours to obtain a leachate;

[0037] S3: Wait for the temperature of the leachate to drop to 50 - 60 °C, add thioacetamide to the leachate, and stir to dissolve it;

[0038] S4: Then add potassium hydroxide to the solution and stir to dissolve it;

[0039] S5: Transfer the solution to a quartz reaction vessel at 95 - 120 °C and stir and react for 10 - 15 hours. After the reaction ends, separate out the black powder product;

[0040] S6: Rinse it 3 times with pure water - absolute ethanol - pure water in a cycle, and vacuum-dry the washed product to obtain the nano-powder of the overall water electrolysis oxygen evolution catalyst for water electrolysis.

[0041] Take 1.0 mg of this powder, coat it on nickel foam, with a loading amount of 1 mg per square centimeter, to obtain the iron-doped cobalt-nickel sulfide water electrolysis catalyst.

[0042] Example 1

[0043] Crush the waste aerospace magnetic materials to pass through 300 meshes, soak them in a 30% calcium chloride solution for 15 minutes, rinse them with clear water, then soak them in a 10% sodium hydroxide solution for 15 minutes, and rinse them with clear water 3 times and dry them;

[0044] Pretreat the waste aerospace magnetic materials, then mix and grind them with sodium chloride and sodium sulfate, ensure that the content of sodium chloride in the mixture is 0.3% and the content of sodium sulfate is 1.5%, and then transfer them to an electric furnace at 550 °C for roasting for 8 h. Cool them with the furnace to room temperature, take out the roasted product, obtain a roasted material, and the chemical composition of this roasted material is shown in Table 1;

[0045] Table 1

[0046]

[0047] Mix anhydrous choline chloride and ethylene glycol in a molar ratio of 1:2 to obtain an anhydrous eutectic ionic liquid solution. Measure 100 mL of this eutectic ionic liquid, add 20 g of roasted waste aerospace magnetic waste material, stir and leach in an oil bath at 100 °C and 300 rpm for 12 hours, then filter to obtain a leachate. After testing, the leaching rate of cobalt in the waste aerospace magnetic material is 96.2%, the leaching rate of nickel is 95.5%, and the leaching rate of iron is 12.1%.

[0048] Take 50 mL of the leachate. When the temperature cools to 50 °C, add 3.8 g of thioacetamide, stir in an oil bath at 100 °C and 300 rpm for 10 minutes, then add 2.0 g of potassium hydroxide and stir for 10 minutes. Stop stirring and let it react statically for 15 hours. After the reaction, filter the black product, wash it 3 times with water and 2 times with ethanol, and vacuum dry it at 50 °C to prepare iron-doped cobalt-nickel sulfide nanopowder. Figure 2 X-ray diffraction analysis shows that the synthesized iron-doped cobalt-nickel-based sulfide is an amorphous structure. Figure 3 Morphology characterization shows that the product is spherical-like particles, evenly dispersed, with uniform particle size, and an average of 86 nm. Figure 4 Energy-dispersive X-ray spectroscopy analysis confirms that it is iron-doped cobalt-nickel sulfide. Figure 5 Electrocatalytic tests show that in a 1.0 mol / L potassium hydroxide solution at 25 °C, its overall water splitting performance reaches E 50 = 1.75 V, E 100 = 1.85 V, showing excellent bifunctional activity.

[0049] Example 2

[0050] Crush the waste aerospace magnetic material to pass through 300 meshes, soak it in 30% calcium chloride solution for 15 minutes, rinse it with clear water, then soak it in 10% sodium hydroxide solution for 15 minutes, rinse it with clear water 3 times, and dry it;

[0051] Pretreat the waste aerospace magnetic material, then mix and grind it with sodium chloride and sodium sulfate to ensure that the content of sodium chloride in the mixture is 0.3% and the content of sodium sulfate is 1.5%. Then transfer it to an electric furnace at 550 °C and roast for 8 hours. Cool it to room temperature with the furnace and take out the roasted product to obtain a roasted material; Mix anhydrous choline chloride and ethylene glycol in a molar ratio of 1:2 to obtain an anhydrous eutectic ionic liquid solution. Measure 100 mL of this eutectic ionic liquid, add 20 g of the roasted waste aerospace magnetic waste material, stir and leach in an oil bath at 110 °C and 300 rpm per minute for 12 hours, then filter to obtain a leachate. After testing, the leaching rate of cobalt in the waste aerospace magnetic material is 96.5%, the leaching rate of nickel is 96.1%, and the leaching rate of iron is 15.1%.

[0052] Take 50 mL of the leaching solution. When the temperature cools down to 50 °C, add 4.0 g of thioacetamide, stir in an oil bath at 100 °C and 300 revolutions per minute for 10 minutes, then add 2.5 g of potassium hydroxide and stir for 10 minutes. Stop stirring and let it react statically for 12 hours. After the reaction is completed, filter the black product, wash it 3 times with water and 2 times with ethanol, and dry it under vacuum at 50 °C to prepare iron-doped cobalt-nickel sulfide nanopowder. The synthesized iron-doped cobalt-nickel-based sulfide has a particle size of 82 nm, and the overall hydrolysis performance is E in a 1.0 mol / L potassium hydroxide solution 50 = 1.73 V, E 100 = 1.81 V.

[0053] Example 3

[0054] Crush the waste aerospace magnetic material to pass through 300 meshes, soak it in 25% calcium chloride solution for 15 minutes, rinse it with clean water, then soak it in 10% sodium hydroxide solution for 15 minutes, rinse it 3 times with clean water, and dry it;

[0055] Pretreat the waste aerospace magnetic material, then mix it with sodium chloride and sodium sulfate and grind it to ensure that the content of sodium chloride in the mixture is 0.3% and the content of sodium sulfate is 1.5%. Then transfer it to an electric furnace at 550 °C and roast it for 8 hours. Cool it to room temperature with the furnace and take out the roasted product to obtain the roasted material; Mix anhydrous choline chloride and ethylene glycol in a molar ratio of 1:2 to obtain an anhydrous eutectic ionic liquid solution. Measure 100 mL of this eutectic ionic liquid, add 20 g of the roasted waste aerospace magnetic material, stir and leach in an oil bath at 105 °C and 300 revolutions per minute for 12 hours, then filter to obtain the leaching solution. After testing, the leaching rate of cobalt in the waste aerospace magnetic material is 97.5%, the leaching rate of nickel is 95.7%, and the leaching rate of iron is 13.1%.

[0056] Take 50 mL of the leaching solution. When the temperature cools down to 50 °C, add 4.2 g of thioacetamide, stir in an oil bath at 100 °C and 300 revolutions per minute for 10 minutes, then add 2.0 g of potassium hydroxide and stir for 10 minutes. Stop stirring and let it react statically for 15 hours. After the reaction is completed, filter the black product, wash it 3 times with water and 2 times with ethanol, and dry it under vacuum at 50 °C to prepare iron-doped cobalt-nickel sulfide nanopowder. The synthesized iron-doped cobalt-nickel-based sulfide has a particle size of 92 nm, and the overall hydrolysis performance is E in a 1.0 mol / L potassium hydroxide solution 50 = 1.77 V, E 100 = 1.89 V.

[0057] By comparing the experimental results of Examples 1 to 3, it can be seen that the recycling preparation method provided by the present invention can effectively control the morphology and catalytic performance of iron-doped cobalt nickel sulfide. Among them, in Example 1, under the optimized conditions of leaching temperature of 100 °C, thioacetamide of 3.8 g, and potassium hydroxide of 2.0 g, the obtained catalyst presents a spherical particle morphology with a uniform particle size distribution (average 86 nm), and exhibits excellent bifunctional electrocatalytic activity in a 1.0 mol / L potassium hydroxide electrolyte (E 50 = 1.75 V, E 100 = 1.85 V). When the reaction parameters are adjusted, Example 2 (thioacetamide 4.0 g / potassium hydroxide 2.5 g) and Example 3 (thioacetamide 4.2 g / potassium hydroxide 2.0 g) obtain nanoparticles of 82 nm and 92 nm respectively. Although the particle size distribution is slightly discrete, the catalytic performance still remains at a high level (E 50 are 1.73 V and 1.77 V respectively, E 100 are 1.81 V and 1.89 V respectively). It is worth noting that a moderate increase in the amount of potassium hydroxide (Example 2) can improve the hydrogen evolution activity, while an excessive amount of thioacetamide (Example 3) may lead to an increase in sulfur vacancies, resulting in a slight increase in the overpotential. This series of experiments shows that by precisely controlling the ratio of sulfur source to base source, the material morphology characteristics can be optimized while ensuring the catalytic activity.

[0058] The above examples describe the basic preparation process of the present invention and the application scope of the application research of electrolytic water hydrogen production. Those skilled in the art should understand that the present invention is not limited by the above examples. What is described in the above examples and the specification only illustrates the principle and preparation process of the present invention. Without departing from the principle of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for preparing an iron-doped cobalt-nickel sulfide catalyst from waste aerospace magnetic materials, characterized in that, It includes the following steps: S1: Pretreat the waste aerospace magnetic material, mix it with additive M, grind it, transfer it to an electric furnace at 500 - 550 °C for roasting for 6 - 8 hours, cool it to room temperature with the furnace, take out the roasted product to obtain roasted material A, and seal it for standby; S2: Add roasted material A to the eutectic ionic liquid at 80 - 120 °C and stir for leaching to obtain leaching solution B; S3: Lower the temperature of leaching solution B to 50 - 60 °C, then add thioacetamide to leaching solution B and stir to dissolve to obtain solution C; S4: Add potassium hydroxide to solution C and stir to dissolve to obtain solution D; S5: Transfer solution D to a quartz reaction vessel at 95 - 120 °C and stir for reaction for 10 - 15 hours. After the reaction, separate out the black powder product; S6: Rinse it 3 times with pure water - absolute ethanol - pure water in a cycle, and vacuum - dry the washed product to obtain the iron - doped cobalt - nickel sulfide electrocatalyst nano - powder for electrolyzing water.

2. The method for preparing an iron-doped cobalt nickel sulfide catalyst from waste aerospace magnetic materials according to claim 1, wherein In step S1, the cobalt content in the waste aerospace magnetic material is 5 - 40%, the nickel content is 1 - 25%, and the iron content is 4 - 40%.

3. The method for preparing an iron-doped cobalt-nickel sulfide catalyst from waste aerospace magnetic materials according to claim 1, wherein In step S1, the pretreatment method of the waste aerospace magnetic material is to crush it to pass through 200 - 300 meshes, soak it in a 20 - 40% calcium chloride solution for 10 - 15 minutes, rinse it with clean water, then soak it in a 10 - 15% sodium hydroxide solution for 10 - 15 minutes, rinse it with clean water 2 - 3 times, and dry it.

4. The method for preparing an iron-doped cobalt-nickel sulfide catalyst from waste aerospace magnetic materials according to claim 1, wherein In step S1, additive M is a mixture of sodium chloride and sodium sulfate. The addition amount of sodium chloride is 0.2 - 0.5%, the addition amount of sodium sulfate is 1 - 2%, and the mass ratio of sodium chloride to sodium sulfate is 1:(4 - 5).

5. The method for preparing an iron-doped cobalt-nickel sulfide catalyst from waste aerospace magnetic materials according to claim 1, characterized in that, In step S2, the eutectic ionic liquid is an organic solvent obtained by mixing choline chloride and ethylene glycol at 40 - 50 °C according to a molar ratio of 1:(2 - 4).

6. The method for preparing an iron-doped cobalt-nickel sulfide catalyst from waste aerospace magnetic materials according to claim 1, wherein In step S1, the particle size of roasted material A is 50 - 60 microns.

7. The method for preparing an iron-doped cobalt-nickel sulfide catalyst from waste aerospace magnetic materials according to claim 1, characterized in that, In step S2, the addition amount of A in the eutectic ionic liquid is 10 - 300 g / L, the stirring speed is 300 - 500 revolutions per minute, and the leaching time is 6 - 12 hours.

8. The method for preparing an iron-doped cobalt-nickel sulfide catalyst from waste aerospace magnetic materials according to claim 1, characterized in that, In step S3, thioacetamide is an anhydrous reagent and its dosage is 0.5 - 2 g / L; in step S4, the dosage of potassium hydroxide is 5 - 15 g / L. The molar ratio of the addition amount of thioacetamide to the cobalt content in leaching solution B is (2 - 3):1, and the molar ratio of the addition amount of potassium hydroxide to the cobalt content in leaching solution B is (2 - 3):

1.

9. A catalyst of iron-doped cobalt nickel sulfide, characterized in that, It is prepared by using the method for preparing an iron - doped cobalt - nickel sulfide catalyst from waste aerospace magnetic materials according to any one of claims 1 - 8.

10. An application of the iron - doped cobalt - nickel sulfide catalyst as described in claim 9 as an electrocatalyst in alkaline - condition electrolysis of water.

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