Method for preparing Fe-Co bimetallic catalyst from iron and steel smelting dust and application of Fe-Co bimetallic catalyst

Abstract

The invention provides a method for preparing a Fe-Co bimetallic catalyst from iron and steel smelting dust and application of the Fe-Co bimetallic catalyst, and belongs to the technical field of catalytic materials. The method comprises the following steps: uniformly mixing an iron-rich component extracted from iron and steel smelting dust with a cobalt salt solution to obtain a mixed solution; reacting the mixed solution at 40-70 DEG C for 3-6 hours, and removing excessive solvent; and carrying out compression molding on the obtained mixture, and calcining in an oxygen atmosphere and a reducing atmosphere to obtain the Fe-Co bimetallic catalyst. The method provided by the invention is simple, and the obtained Fe-Co bimetallic catalyst has high activity and low raw material cost, and has a good application prospect in the aspect of electro-catalysis nitrogen reduction reaction.

Description

Technical Field

[0001] The present invention relates to the technical field of catalytic materials, and specifically relates to a method for preparing an Fe-Co bimetallic catalyst by using steelmaking dust and its application. Background Art

[0002] Electrochemical ammonia synthesis is a new clean energy storage and conversion technology, which can partly solve the current human fossil energy crisis and environmental pollution problems. In the electrochemical ammonia synthesis technology, a very important electrocatalytic reaction is involved, namely the nitrogen reduction reaction. However, the current nitrogen reduction reaction rate is slow, which severely restricts the operation efficiency. Although noble metals such as Ru, Ir, Pt, etc. have good catalytic effects and can improve the reaction rate, their high prices limit their large-scale use. Therefore, there is an urgent need to develop catalysts with low prices and excellent performance.

[0003] China is a major steel manufacturing country, and a huge amount of dust is generated in steelmaking. On the one hand, the large accumulation of this dust causes environmental pollution and urgent treatment is needed; on the other hand, the main chemical components of this dust are metal oxides, especially iron oxides. And iron-cobalt alloy has been proved to be an excellent nitrogen reduction catalyst. Therefore, based on steelmaking dust and cobalt salt, the present invention prepares an Fe-Co bimetallic catalyst, which has high activity and low raw material cost, and has good application prospects in electrocatalytic nitrogen reduction. Summary of the Invention

[0004] Aiming at the above deficiencies of the prior art, the present invention provides a method for preparing an Fe-Co bimetallic catalyst by using steelmaking dust and its application, so as to solve the problems of high reaction overpotential, short life, high cost, etc. existing in the electrocatalytic nitrogen reduction technology in the prior art.

[0005] To achieve the above object, the specific technical solutions of the present invention are as follows:

[0006] In the first aspect, the present invention provides a method for preparing an Fe-Co bimetallic catalyst by using steelmaking dust, including the following steps:

[0007] Mix the iron-rich component extracted from steelmaking dust with a cobalt salt solution evenly to obtain a mixed solution; after reacting the mixed solution at 40-70 °C, remove the excessive solvent; after pressing the obtained mixture into a shape, calcine it in an oxygen atmosphere and a reducing atmosphere respectively to obtain an Fe-Co bimetallic catalyst.

[0008] Further, in the Fe-Co bimetallic catalyst, the mass fraction of Co is 2% - 20%.

[0009] Further, the cobalt salt solution is an aqueous solution of cobalt salt, and the cobalt salt includes at least one of cobalt nitrate, cobalt chloride, and cobalt sulfate, etc.

[0010] Further, the steelmaking dust includes at least one of oxygen converter fume, oxygen blown open hearth fume, and electric furnace fume. The iron-rich component separated from the steelmaking dust in the present invention mainly includes: iron oxides FeO and Fe2O3, iron sulfide FeS, and fayalite 2FeO·SiO2. Taking the iron components in the No. 1 blast furnace dust of WISCO as an example, more than 80% of the components are FeO, and the iron content is 40% - 85%, and the iron content depends on the types of different steelmaking dusts.

[0011] Further, the iron-rich component and the cobalt salt solution are stirred and mixed under the condition of enhanced high-temperature ultrasonic waves to obtain a mixed solution; the temperature of the stirring and mixing is 50 - 70 °C, and the time is 3 - 6 h.

[0012] Further, the reaction time is 3 - 6 h.

[0013] Further, the excessive solvent is removed by evaporation, and the temperature used for evaporation is 90 - 100 °C.

[0014] Further, the shape in the pressing and forming includes any one of spherical, cylindrical, and square shapes, etc.

[0015] Further, the temperature of the calcination is 300 - 600 °C, and the time is 2 - 6 h.

[0016] Further, the reducing atmosphere includes hydrogen, or a gas mixture composed of hydrogen and an inert gas.

[0017] Specifically, the method for preparing the Fe-Co bimetallic catalyst using steelmaking dust includes the following steps:

[0018] (1) Add cobalt salt into water, and obtain a cobalt salt solution after ultrasonic oscillation; separate the iron-rich component from the steelmaking dust;

[0019] (2) Add the iron-rich component into the cobalt salt solution, and stir and mix under the condition of enhanced high-temperature ultrasonic waves to obtain a mixed solution;

[0020] (3) React the mixed solution at 40 - 70 °C for 3 - 6 h. After the reaction is completed, evaporate the excessive water to form a sample with a water content of 4% - 20%;

[0021] (4) Press the sample into shape, and calcine it at 300 - 600 °C for 2 - 6 h in an oxygen atmosphere and a reducing atmosphere respectively to obtain the Fe-Co bimetallic catalyst.

[0022] In a second aspect, the present invention provides an Fe-Co bimetallic catalyst prepared by using the above method.

[0023] In a third aspect, the present invention provides the application of the Fe-Co bimetallic catalyst in electrocatalytic nitrogen reduction.

[0024] The principle of the present invention is as follows: The interaction between Fe and Co in the catalyst can adjust the adsorption strength of small reaction intermediates on the catalyst surface, thereby exhibiting excellent catalytic performance. The closer the d-band center of the active site is to the Fermi level, the higher the adsorption strength. In the Fe-Co bimetallic catalyst, Co is the catalytic active site, and Fe mainly plays the role of changing the electron distribution on the catalyst surface and adjusting the d-band center of Co atoms.

[0025] Compared with the prior art, the advantages of the present invention are as follows:

[0026] (1) The present invention provides a nitrogen reduction catalyst that can achieve electrocatalytic nitrogen reduction to produce ammonia; the active components on the surface of the catalyst are Fe and Co, and the catalyst is mainly composed of iron-rich components separated from steelmaking dust and cobalt reduced from the mineral lattice. The synergistic enhancement between iron and cobalt enables the material to have good catalytic performance.

[0027] (2) The iron-rich component in the catalyst of the present invention is obtained from oxygen converter dust, oxygen-blown open-hearth furnace dust, and electric furnace dust. This method can greatly promote the resource utilization of by-products in steelmaking and reduce the production cost of the catalyst at the same time.

[0028] (3) The preparation method of the catalyst of the present invention is simple, the prepared catalyst is inexpensive, has good reaction performance, and has good application prospects in electrocatalytic nitrogen reduction. Description of the Drawings

[0029] Figure 1 is a comparison diagram of overpotentials of the reactions of 2% Co / SSD, 5% Co / SSD, 10% Co / SSD, 15% Co / SSD, and 20% Co / SSD catalysts in Application Examples 1 to 35 at different potentials; wherein, the SSD is the abbreviation of steelmelting dust;

[0030] Figure 2 is the linear sweep voltammogram of the 2% Co / SSD catalyst in a 1M NaHCO3 solution in Application Example 1. Detailed Embodiments

[0031] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention.

[0032] The present invention provides a method for preparing an Fe-Co bimetallic catalyst using steelmaking dust, comprising the following steps:

[0033] Mix the iron-rich component extracted from steelmaking dust with a cobalt salt solution evenly to obtain a mixed solution; after reacting the mixed solution at 40-70 °C, remove the excess solvent; after pressing the obtained mixture into a shape, calcine it in an oxygen atmosphere and a reducing atmosphere respectively to obtain an Fe-Co bimetallic catalyst.

[0034] In some examples, in the Fe-Co bimetallic catalyst, the mass fraction of Co is 2%-20%.

[0035] In some examples, the cobalt salt solution is an aqueous solution of cobalt salt, and the cobalt salt includes but is not limited to at least one of cobalt nitrate, cobalt chloride, and cobalt sulfate.

[0036] In some examples, the steelmaking dust includes but is not limited to at least one of oxygen converter dust, oxygen blown open hearth dust, and electric furnace dust.

[0037] In some examples, the iron-rich component and the cobalt salt solution are stirred and mixed under the condition of enhanced high-temperature ultrasonic waves to obtain a mixed solution; the temperature of the stirring and mixing is 50-70 °C, and the time is 3-6 h.

[0038] In some examples, the reaction time is 3-6 h.

[0039] In some examples, the excess solvent is removed by evaporation, and the temperature used for evaporation is 90-100 °C.

[0040] In some examples, the shape in the pressing into a shape includes but is not limited to any one of spherical, cylindrical, and square.

[0041] In some examples, the temperature of the calcination is 300-600 °C, and the time is 2-6 h.

[0042] In some examples, the reducing atmosphere includes hydrogen, or a mixed gas composed of hydrogen and an inert gas.

[0043] In the following examples and comparative examples, unless otherwise specified, all raw materials are common raw materials on the market, and the methods used are all conventional methods.

[0044] Example 1

[0045] An Fe-Co bimetallic catalyst prepared from steelmaking dust, and its preparation method includes the following steps:

[0046] S1. Add 50 mL of deionized water to a 100 mL beaker, add 0.20 g of Co(NO3)2·6H2O crystals to the beaker, and ultrasonically vibrate for 10 min to obtain a cobalt salt solution;

[0047] S2. Use a magnet to separate the iron-rich component from the electric furnace dust. The iron content in the iron-rich component is 70%. Weigh 2.8 g of the iron-rich component and add it to the cobalt salt solution obtained in S1. Ultrasonically stir for 3 h at a temperature of 60 °C to obtain a mixed solution;

[0048] S3. Heat the mixed solution obtained in S3 in a magnetic stirrer at 50 °C to allow the metal cobalt ions to react with the iron-rich component for 3 h. After the reaction is completed, raise the temperature of the stirrer to 95 °C to evaporate the water in the obtained mixture to obtain a sample with a moisture content of 8%. Then press the sample into a square shape on a molding machine to obtain a molded sample;

[0049] S4. Put the molded sample obtained in S3 into a tubular furnace at 400 °C and calcine it in an oxygen atmosphere and a hydrogen atmosphere for 2 h in sequence to obtain a highly efficient Fe-Co bimetallic catalyst with a cobalt mass fraction of 2%, denoted as 2%Co / SSD.

[0050] Example 2

[0051] An Fe-Co bimetallic catalyst prepared from steelmaking dust, and its preparation method includes the following steps:

[0052] S1. Add 50 mL of deionized water to a 100 mL beaker, add 0.49 g of Co(NO3)2·6H2O crystals to the beaker, and ultrasonically vibrate for 10 min to obtain a cobalt salt solution;

[0053] S2. Use a magnet to separate the iron-rich component from the electric furnace dust. The iron content in the iron-rich component is 70%. Weigh 2.71 g of the iron-rich component and add it to the cobalt salt solution obtained in S1. Ultrasonically stir for 3 h at a temperature of 60 °C to obtain a mixed solution;

[0054] S3. Heat the mixed solution obtained in S3 in a magnetic stirrer at 50 °C to allow the metal cobalt ions to react with the iron-rich component for 3 h. After the reaction is completed, raise the temperature of the stirrer to 95 °C to evaporate the water in the obtained mixture to obtain a sample with a moisture content of 8%. Then press the sample into a square shape on a molding machine to obtain a molded sample;

[0055] S4. Put the formed sample obtained in S3 into a tubular furnace at 400 °C and calcine it for 2 h successively in an oxygen atmosphere and a hydrogen atmosphere to obtain a highly efficient catalyst of Fe-Co bimetallic catalyst with a cobalt mass fraction of 5%, denoted as 5%Co / SSD.

[0056] Example 3

[0057] An Fe-Co bimetallic catalyst prepared from steelmaking dust, and its preparation method includes the following steps:

[0058] S1. Add 50 mL of deionized water to a 100 mL beaker, add 0.99 g of Co(NO3)2·6H2O crystals to the beaker, and ultrasonically vibrate for 10 min to obtain a cobalt salt solution;

[0059] S2. Use a magnet to separate the iron-rich component from the electric furnace dust. The iron content in the iron-rich component is 70%. Weigh 2.57 g of the iron-rich component and add it to the cobalt salt solution obtained in S1. Ultrasonically stir for 3 h at a temperature of 60 °C to obtain a mixed solution;

[0060] S3. Heat the mixed solution obtained in S3 in a magnetic stirrer at 50 °C, allow the metal cobalt ions to react with the iron-rich component for 3 h. After the reaction, raise the temperature of the stirrer to 95 °C, evaporate the water in the obtained mixture to obtain a sample with a moisture content of 8%, and then press the sample into a square shape on a molding machine to obtain a formed sample;

[0061] S4. Put the formed sample obtained in S3 into a tubular furnace at 400 °C and calcine it for 2 h successively in an oxygen atmosphere and a hydrogen atmosphere to obtain a highly efficient catalyst of Fe-Co bimetallic catalyst with a cobalt mass fraction of 10%, denoted as 10%Co / SSD.

[0062] Example 4

[0063] An Fe-Co bimetallic catalyst prepared from steelmaking dust, and its preparation method includes the following steps:

[0064] S1. Add 50 mL of deionized water to a 100 mL beaker, add 1.48 g of Co(NO3)2·6H2O crystals to the beaker, and ultrasonically vibrate for 10 min to obtain a cobalt salt solution;

[0065] S2. Use a magnet to separate the iron-rich component from the electric furnace dust. The iron content in the iron-rich component is 70%. Weigh 2.43 g of the iron-rich component and add it to the cobalt salt solution obtained in S1. Ultrasonically stir for 3 h at a temperature of 60 °C to obtain a mixed solution;

[0066] S3. Heat the mixed solution obtained in S3 in a magnetic stirrer at 50 °C, allowing the metal cobalt ions to react with the iron-rich component for 3 h. After the reaction, raise the temperature of the stirrer to 95 °C and evaporate the water in the resulting mixture to obtain a sample with a moisture content of 8%. Then press the sample into a square shape on a molding machine to obtain a molded sample.

[0067] S4. Place the molded sample obtained in S3 into a tubular furnace at 400 °C and calcine it for 2 h successively in an oxygen atmosphere and a hydrogen atmosphere to obtain a highly efficient Fe-Co bimetallic catalyst with a cobalt mass fraction of 15%, denoted as 15%Co / SSD.

[0068] Example 5

[0069] An Fe-Co bimetallic catalyst prepared from steelmaking dust, and its preparation method includes the following steps:

[0070] S1. Add 50 mL of deionized water to a 100 mL beaker, add 1.97 g of Co(NO3)2·6H2O crystals to the beaker, and ultrasonically vibrate for 10 min to obtain a cobalt salt solution.

[0071] S2. Use a magnet to separate the iron-rich component from the electric furnace dust. The iron content in the iron-rich component is 70%. Weigh 2.29 g of the iron-rich component and add it to the cobalt salt solution described in S1, and ultrasonically stir for 3 h at a temperature of 60 °C to obtain a mixed solution.

[0072] S3. Heat the mixed solution obtained in S3 in a magnetic stirrer at 50 °C, allowing the metal cobalt ions to react with the iron-rich component for 3 h. After the reaction, raise the temperature of the stirrer to 95 °C and evaporate the water in the resulting mixture to obtain a sample with a moisture content of 8%. Then press the sample into a square shape on a molding machine to obtain a molded sample.

[0073] S4. Place the molded sample obtained in S3 into a tubular furnace at 400 °C and calcine it for 2 h successively in an oxygen atmosphere and a hydrogen atmosphere to obtain a highly efficient Fe-Co bimetallic catalyst with a cobalt mass fraction of 20%, denoted as 20%Co / SSD.

[0074] The electrocatalytic nitrogen reduction catalytic function of the catalysts in Examples 1-5 of the present invention was tested in an electrochemical reaction cell, and corresponding test data were obtained in an electrochemical workstation.

[0075] Application Example 1

[0076] Weigh 10 mg of the 2% Co / SSD catalyst prepared in Example 1 into a plastic centrifuge tube, add 10 μL of Nafion solution and 40 μL of ethanol, mix well, perform ultrasonic treatment, and then suck it up with a micropipette. Coat the obtained mixture evenly on the surface of a carbon paper with a size of 1×2 cm 2 , and then air-dry it at room temperature for several hours to obtain a working electrode. An Ag / AgCl electrode and a platinum sheet are used as the reference electrode and the counter electrode, respectively. The electrode potential of the reaction is controlled at -0.7 V vs RHE.

[0077] Application Examples 2 - 7

[0078] Application Examples 2 - 7 are basically the same as Application Example 1, except that: the electrode potentials of Application Examples 2 - 7 are -0.8 V vs RHE, -0.9 V vs RHE, -1 V vs RHE, -1.1 V vs RHE, -1.2 V vs RHE, and -1.3 V vs RHE, respectively.

[0079] Application Example 8

[0080] Application Example 8 is basically the same as Application Example 1, except that: the catalyst used in Application Example 8 is the 5% Co / SSD prepared in Example 2.

[0081] Application Examples 9 - 14

[0082] Application Examples 9 - 14 are basically the same as Application Example 8, except that: the electrode potentials of Application Examples 9 - 14 are -0.8 V vs RHE, -0.9 V vs RHE, -1 V vs RHE, -1.1 V vs RHE, -1.2 V vs RHE, and -1.3 V vs RHE, respectively.

[0083] Application Example 15

[0084] Application Example 15 is basically the same as Application Example 1, except that: the catalyst used in Application Example 15 is the 10% Co / SSD prepared in Example 3.

[0085] Application Examples 16 - 21

[0086] Application Examples 16 - 21 are basically the same as Application Example 15, except that: the electrode potentials of Application Examples 16 - 21 are -0.8 V vs RHE, -0.9 V vs RHE, -1 V vs RHE, -1.1 V vs RHE, -1.2 V vs RHE, and -1.3 V vs RHE, respectively.

[0087] Application Example 22

[0088] Application Example 22 is basically the same as Application Example 1, except that: the catalyst used in Application Example 22 is 15% Co / SSD prepared in Example 4.

[0089] Application Examples 23 - 28

[0090] Application Examples 23 - 28 are basically the same as Application Example 22, except that: the electrode potentials of Application Examples 23 - 28 are -0.8 V vs RHE, -0.9 V vs RHE, -1 V vs RHE, -1.1 V vs RHE, -1.2 V vs RHE, -1.3 V vs RHE, respectively.

[0091] Application Example 29

[0092] Application Example 29 is basically the same as Application Example 1, except that: the catalyst used in Application Example 29 is 20% Co / SSD prepared in Example 5.

[0093] Application Examples 30 - 35

[0094] Application Examples 30 - 35 are basically the same as Application Example 29, except that: the electrode potentials of Application Examples 30 - 35 are -0.8 V vs RHE, -0.9 V vs RHE, -1 V vs RHE, -1.1 V vs RHE, -1.2 V vs RHE, -1.3 V vs RHE, respectively.

[0095] Comparative Example 1

[0096] Weigh 10 mg of cobalt - iron metal supported on nitrogen - doped carbon catalyst (CoFe - N / C) into a plastic centrifuge tube, add 10 μL of Nafion solution and 40 μL of ethanol, mix evenly, perform ultrasonic treatment and suck it up with a micropipette. The obtained mixed solution is evenly coated on the surface of a 1×2 cm 2 carbon paper, and then air - dried at room temperature for several hours to obtain a working electrode. An Ag / AgCl electrode and a platinum sheet are used as the reference electrode and the counter electrode, respectively. The electrode potential of the reaction is controlled at -0.7 V vs RHE. The preparation method of CoFe - N / C refers to Patent CN115679340A.

[0097] Comparative Example 2

[0098] Weigh 10 mg of Fe2O3 catalyst into a plastic centrifuge tube, add 10 μL of Nafion solution and 40 μL of ethanol, mix evenly, perform ultrasonic treatment and suck it up with a micropipette. The obtained mixed solution is evenly coated on the surface of a 1×2 cm 2Onthe surface of the carbon paper, and then air-dried at room temperature for several hours to obtain the working electrode. The Ag / AgCl electrode and the platinum sheet were used as the reference electrode and the counter electrode, respectively. The electrode potential of the reaction was controlled at -0.7 V vs RHE. The Fe2O3 catalyst was prepared with reference to the following literature: Johann Kirchner, Jasmin Katharina Anolleck, Henry Lösch, et al. Methanation of CO2 on iron based catalysts. Applied Catalysis B: Environmental 223 (2018) 47-59.

[0099] Comparative Example 3

[0100] Weigh 10 mg of the Mg / Fe2O3 catalyst into a plastic centrifuge tube, add 10 μL of Nafion solution and 40 μL of ethanol, mix well, ultrasonically treat and suck with a micropipette, and evenly coat the obtained mixture on a 1×2 cm 2 Onthe surface of the carbon paper, and then air-dried at room temperature for several hours to obtain the working electrode. The Ag / AgCl electrode and the platinum sheet were used as the reference electrode and the counter electrode, respectively. The electrode potential of the reaction was controlled at -0.7 V vs RHE. The Mg / Fe2O3 catalyst was prepared with reference to the following literature: Zeynep Baysal, Sven Kureti. CO2 methanation on Mg promoted Fe catalysts. Applied Catalysis B: Environmental 262 (2020) 118300.

[0101] Table 1 Comparison results of overpotential performance between Application Example 1 and Comparative Examples 1-3

[0102]

[0103] The overpotential of the reaction under the condition of a current density of 10 mA·cm -2 is an important indicator to measure the performance of the catalyst. It can be seen from Table 1 that the reaction overpotentials of different catalysts CoFe-N / C, Fe2O3 and Mg / Fe2O3 in Comparative Examples 1-3 are significantly higher than those of the 2% Co / SSD catalyst of the present invention.

[0104] It can be seen from Figure 1 that the overpotential of the reaction of the catalyst of the present invention is relatively low in a wide range of working voltages (-0.7 V vs RHE ~ -1.3 V vs RHE), indicating that the Fe-Co bimetallic catalyst of the present invention has excellent catalytic performance.

[0105] In addition, a stability test was conducted on the 2% Co / SSD catalyst of the present invention. The test environment was 1 M NaHCO3 electrolyte at room temperature, and the overpotential tested was 135 mV. The test results are as Figure 2 shown. It can be seen from Figure 2 that the catalyst can stably operate for more than 60 h at a constant voltage with an overpotential of 135 mV, indicating that the 2% Co / SSD catalyst prepared by the present invention has excellent stability.

[0106] In summary, in the present invention, the iron-rich component extracted from steelmaking dust is mixed evenly with a cobalt salt solution. After reacting at 40-70 °C for 3-6 h, the excess solvent is removed, and then it is pressed into shape and calcined in an oxygen atmosphere and a reducing atmosphere respectively to obtain an Fe-Co bimetallic catalyst. The method provided by the present invention is simple, can greatly promote the resource utilization of by-products in steelmaking, and has low production costs; the prepared Fe-Co bimetallic catalyst has excellent catalytic activity and has good application prospects in the electrocatalytic nitrogen reduction reaction.

[0107] The above specific embodiments have described the implementation of the present invention in detail. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple variations all belong to the protection scope of the present invention.

Claims

1. A method for preparing an Fe-Co bimetallic catalyst using steelmaking dust, characterized in that, It includes the following steps: Mix the iron-rich component extracted from steelmaking dust evenly with a cobalt salt solution to obtain a mixed solution; after reacting the mixed solution at 40-70 °C, remove the excessive solvent; after pressing the obtained mixture into a shape, calcine it in an oxygen atmosphere and a reducing atmosphere respectively to obtain an Fe-Co bimetallic catalyst.

2. The method for preparing an Fe-Co bimetallic catalyst by using steelmaking dust according to claim 1, wherein In the Fe-Co bimetallic catalyst, the mass fraction of Co is 2%-20%.

3. A method for preparing an Fe-Co bimetallic catalyst using steelmaking dust according to claim 1, characterized in that, The cobalt salt solution is an aqueous solution of cobalt salt, and the cobalt salt includes but is not limited to at least one of cobalt nitrate, cobalt chloride, and cobalt sulfate.

4. A method for preparing an Fe-Co bimetallic catalyst using steelmaking dust according to claim 1, characterized in that, The steelmaking dust includes but is not limited to at least one of oxygen converter fumes, oxygen-blown open-hearth fumes, and electric furnace fumes.

5. A method for preparing an Fe-Co bimetallic catalyst using steelmaking dust according to claim 1, characterized in that, Stir and mix the iron-rich component with the cobalt salt solution under the condition of enhanced high-temperature ultrasonic waves to obtain a mixed solution; the temperature of the stirring and mixing is 50-70 °C, and the time is 3-6 h.

6. A method for preparing an Fe-Co bimetallic catalyst using steelmaking dust according to claim 1, characterized in that, The reaction time is 3-6 h.

7. A method for preparing an Fe-Co bimetallic catalyst using steelmaking dust according to claim 1, characterized in that, Remove the excessive solvent by evaporation, and the temperature used for evaporation is 90-100 °C.

8. A method for preparing an Fe-Co bimetallic catalyst using steelmaking dust according to claim 1, characterized in that, The temperature of the calcination is 300-600 °C, and the time is 2-6 h.

9. An Fe-Co bimetallic catalyst prepared by the method according to any one of claims 1-8.

10. Use of the Fe-Co bimetallic catalyst according to claim 9 in electrocatalytic nitrogen reduction.

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