A high-entropy alloy / nitrogen-doped carbon nanocatalytic material, its preparation method and application

Abstract

The present application discloses a high-entropy alloy / nitrogen-doped carbon nanocatalytic material, its preparation method and application. The nanocatalytic material includes a high-entropy alloy composed of five non-precious metals, namely Fe, Co, Ni, Cu and Mn, and nitrogen-doped carbon synthesized with the assistance of MOF. Among them, the non-precious metal high-entropy alloy serves as the main material, and the nitrogen-doped carbon serves as the carrier material. The non-precious metal high-entropy alloy is loaded on the nitrogen-doped carbon to construct a novel nanocatalytic material, which is used to activate persulfate to remove antibiotics in water bodies. It has advantages such as excellent chemical stability and good reusability, and is a novel nanocatalytic material with both high catalytic performance and environmentally friendly characteristics. Its preparation method has the advantages of simple operation process, green environmental protection, economic feasibility, etc., and can be used for large-scale preparation.

Description

Technical Field

[0001] The present application relates to the technical field of environmental functional nanomaterials, and in particular to a high entropy alloy / nitrogen-doped carbon nanocatalytic material and a preparation method and application thereof. Background Art

[0002] With the rapid development of medicine, animal husbandry and aquaculture, antibiotics are widely used. However, most antibiotics that cannot be metabolized in the body are released into various water bodies through excrement, causing water pollution and posing a serious threat to the ecological environment and human health. Although traditional water treatment methods such as physical adsorption, chemical degradation and biological treatment can remove some antibiotics in water, they usually have problems such as low efficiency, high cost and easy secondary pollution. Therefore, the development of economical, efficient, green and adaptable antibiotic removal technology has become a key environmental issue that needs to be solved urgently.

[0003] In recent years, advanced oxidation processes (AOPs) have become an important technology in the field of water pollution control due to their high efficiency and wide applicability. Among various AOPs, persulfate-based advanced oxidation processes have shown unique advantages in the field of water treatment. Compared with AOPs that mainly rely on hydroxyl radicals, the sulfate radical-driven oxidation process has stronger oxidation ability, longer half-life and wider pH application range. In addition, as an oxidant, persulfate has higher catalytic efficiency, lower cost, better stability and safety than traditional oxidants such as hydrogen peroxide, and is easy to store and transport. More importantly, persulfate can be activated in a variety of ways, including external energy such as ultraviolet rays, homogeneous systems such as transition metal ions, and heterogeneous systems such as metal oxides. Among them, heterogeneous systems provide great flexibility and adaptability for process design and application. At present, the main problem of this technology is the rational design and catalytic activity of the catalyst. Therefore, it is crucial to develop efficient, stable and reusable catalytic materials.

[0004] As a new type of catalytic material, high-entropy alloy exhibits unique advantages in persulfate activation due to its unique surface electronic structure and physicochemical properties. First, high-entropy alloy is composed of multiple metal elements in nearly equimolar ratios. Its unique high-entropy structure endows the alloy with multiple metal active centers and excellent electron transport ability, enabling the optimization of the electronic structure of metal active sites through synergistic effects and significantly enhancing the activation efficiency of persulfate. Second, the high chemical stability and corrosion resistance of high-entropy alloy ensure the long-term stable operation of the catalyst in complex environments, avoiding problems such as metal ion migration or catalyst deactivation. Third, the uniform distribution of multiple metal elements in high-entropy alloy provides more active centers, thereby accelerating the efficient transfer of electrons, promoting the decomposition of persulfate to generate stronger oxidizing species (such as sulfate radicals and hydroxyl radicals), and enhancing the pollutant degradation efficiency. Nevertheless, there are still certain disadvantages in the process of high-entropy alloy monomers activating persulfate. First, the surface energy of nanoscale high-entropy alloy is relatively high, and it is prone to agglomeration during the preparation and activation of persulfate, resulting in the burial of a large number of active sites. Second, although the synergistic effect of multi-metal sites can improve the activity, the complex metal-metal interactions may lead to insufficient activity at some sites and even the generation of non-target by-products, reducing the catalytic efficiency and selectivity. The recovery and reuse of complex metal components are relatively difficult, increasing the economic and technical burdens in their practical applications.

[0005] Constructing a new type of nanocatalytic material by loading high-entropy alloy nanoparticles on the surface of nitrogen-doped carbon materials is expected to solve the problems faced by high-entropy alloy monomers. First, the metal-organic framework-derived nitrogen-doped carbon has a unique high specific surface area and porous structure, providing a uniformly dispersed support for high-entropy alloy particles, preventing agglomeration and exposing more active sites. Second, the excellent electron conductivity of nitrogen-doped carbon promotes the efficient transfer of electrons, accelerates the activation of persulfate, and thus enhances the catalytic efficiency. In addition, nitrogen doping can enhance the synergistic effect between the support material and high-entropy alloy, thereby improving the activity of the catalyst. However, there are still some difficulties in constructing this nanocomposite. First, the preparation method of high-entropy alloy is relatively complex, and successfully loading high-entropy alloy on nitrogen-doped carbon is also extremely challenging; second, the mass ratio of high-entropy alloy to nitrogen-doped carbon in the high-entropy alloy / nitrogen-doped carbon nanocatalytic material has a great impact on the performance of this nanomaterial. Therefore, it is of great significance to load high-entropy alloy on the surface of nitrogen-doped carbon nanomaterials to form a new type of nanocomposite and study its properties. Summary of the Invention

[0006] Based on this, the technical problem to be solved by this application is to overcome the deficiencies of the prior art, develop a high-entropy alloy / nitrogen-doped carbon nanocatalytic material with high activation efficiency of persulfate, excellent catalytic performance, and strong stability, and provide a method that is simple to operate, environmentally friendly, and can be used for large-scale preparation of nanocatalysts.

[0007] The technical solution adopted by this application to solve its technical problems is: a high-entropy alloy / nitrogen-doped carbon nanocatalytic material, and the high-entropy alloy / nitrogen-doped carbon nanocatalytic material includes a high-entropy alloy composed of five non-precious metals, namely Fe, Co, Ni, Cu, and Mn, and nitrogen-doped carbon, and the high-entropy alloy is loaded on the nitrogen-doped carbon.

[0008] In some embodiments, the mass ratio of the high-entropy alloy to the nitrogen-doped carbon in the high-entropy alloy / nitrogen-doped carbon nanocatalytic material is 1:1 or 2:1 or 4:1.

[0009] On the other hand, this application provides a preparation method of the above-mentioned high-entropy alloy / nitrogen-doped carbon nanocatalytic material, including the following steps:

[0010] S1. Using 2-methylimidazole and zinc acetate dihydrate as precursors, zeolitic imidazolate framework material-8 (ZIF-8) is prepared by the co-precipitation method;

[0011] S2. ZIF-8 is calcined once to obtain nitrogen-doped carbon;

[0012] S3. Adsorb ferric chloride hexahydrate, cobalt chloride hexahydrate, nickel chloride hexahydrate, copper chloride dihydrate, and manganese chloride tetrahydrate on the surface of nitrogen-doped carbon, and a novel high-entropy alloy / nitrogen-doped carbon nanocatalytic material is obtained by the secondary calcination method.

[0013] Based on the above preparation method, in some embodiments, the specific process of the step S1 is as follows: Dissolve 2-methylimidazole in ultrapure water and ultrasonically form a uniform solution, denoted as solution A; dissolve zinc acetate dihydrate in ultrapure water and magnetically stir to form a uniform solution, denoted as solution B; then add solution A to solution B and stir vigorously, let the obtained white solution stand for aging, and then centrifuge and wash the aged ZIF-8 solution several times, and it can be dried to obtain ZIF-8.

[0014] Based on the above preparation method, in some embodiments, in the step S1: the mass of the 2-methylimidazole is 1.12 g, the volume of the ultrapure water is 5 mL, the mass of the zinc acetate dihydrate is 0.3 g, the ultrasonic time is 10 min, the magnetic stirring time is 3 min, the vigorous stirring time is 10 s, the number of times of washing several times is to alternately wash with water and ethanol for 3-5 times, the drying is vacuum drying, the drying temperature is 60 °C, and the drying time is 12-24 h.

[0015] Based on the above preparation method, in some embodiments, the process of the step S2 is as follows: Place the ZIF-8 obtained in the step S1 in a tube furnace for calcination, and after the reaction ends, wash and dry the obtained black powder to obtain nitrogen-doped carbon.

[0016] Based on the above preparation method, in some embodiments, in step S2: the mass of the ZIF-8 is 2 g, the calcination conditions of the tube furnace are that the calcination temperature is 1000 °C, the heating rate is 2 °C / min, the calcination atmosphere is an Ar environment, the calcination time is 2 h, the cleaning is to alternately clean with water and ethanol for 3 - 5 times, the drying is vacuum drying, the drying temperature is 60 °C, and the drying time is 12 - 24 h.

[0017] Based on the above preparation method, in some embodiments, the specific process of step S3 is as follows: Disperse the nitrogen-doped carbon in an ethanol solution, add the ethanol solutions of ferric chloride hexahydrate, cobalt chloride hexahydrate, nickel chloride hexahydrate, copper chloride dihydrate, and manganese chloride tetrahydrate to the ethanol solution of the nitrogen-doped carbon, and magnetically stir to form a black solution. Then, place the black solid obtained by rotary evaporation in a tube furnace for secondary calcination. After the reaction ends, wash and dry the obtained black powder to obtain the high-entropy alloy / nitrogen-doped carbon nanocatalytic material.

[0018] Based on the above preparation method, in some embodiments, in step S3: the mass of the nitrogen-doped carbon is 50 mg, the ethanol solution is 44 mL, the concentration of the ethanol solution of ferric chloride hexahydrate is 1 mg / mL, and the added volume is 1.1 mL. The concentration of the ethanol solution of cobalt chloride hexahydrate is 25 mg / mL, and the added volume is 247 μL. The concentration of the ethanol solution of nickel chloride hexahydrate is 25 mg / mL, and the added volume is 247 μL. The concentration of the ethanol solution of copper chloride dihydrate is 25 mg / mL, and the added volume is 140 μL. The concentration of the ethanol solution of manganese chloride tetrahydrate is 25 mg / mL, and the added volume is 205 μL. The magnetic stirring time is 24 h, the rotary evaporation temperature is 40 °C, the calcination conditions of the tube furnace are that the calcination temperature is 1000 °C, the heating rate is 10 °C / min, the calcination atmosphere is an Ar environment, the calcination time is 1 h, the cleaning is to alternately clean with water and ethanol for 3 - 5 times, the drying is vacuum drying, the drying temperature is 60 °C, and the drying time is 12 - 24 h.

[0019] In some embodiments, the application of the high-entropy alloy / nitrogen-doped carbon nanocatalytic material for activating persulfate to remove antibiotics in water bodies.

[0020] The beneficial effects of this application are as follows:

[0021] 1. This application constructs a novel nano-catalytic material of high-entropy alloy / nitrogen-doped carbon, which is mainly composed of two novel nano-materials: non-precious metal high-entropy alloy and nitrogen-doped carbon. Among them, the non-precious metal high-entropy alloy is the main material, and the nitrogen-doped carbon material is the carrier material. The high-entropy alloy is loaded on the nitrogen-doped surface to form a novel nano-catalytic material. The non-precious metal high-entropy alloy has advantages such as stable structure, corrosion resistance, and strong electron transport ability. In addition, this high-entropy alloy is composed of five transition metals and has a low cost. Therefore, this photocatalytic material combines the characteristics of environmental friendliness and economic efficiency and has broad application prospects.

[0022] 2. In the high-entropy alloy / nitrogen-doped carbon nano-catalytic material of this application, the nitrogen-doped carbon is a novel carbon material derived from MOF. Its high specific surface area and abundant pore structure can promote the adsorption of metal ions, which is beneficial to the subsequent synthesis of high-entropy alloy. At the same time, nitrogen doping introduces additional electronic structures, enhancing the conductivity and catalytic activity of the carbon material. In addition, nitrogen doping can enhance the adhesion of high-entropy alloy nanoparticles to the carbon material. The nitrogen-doped carbon nano-material also has excellent chemical and thermal stability, providing a stable working environment for the composite catalyst.

[0023] 3. In the high-entropy alloy / nitrogen-doped carbon nano-catalytic material of this application, the prepared high-entropy alloy is composed of multiple metal elements, and the synergistic effect between different metal centers also plays a crucial role in enhancing the catalytic performance of the catalyst. In addition, the prepared high-entropy alloy is composed of five transition metals: Fe, Co, Ni, Cu, and Mn. These transition metal raw materials are relatively cheap and resource-rich. Compared with traditional catalytic materials that rely on precious metals such as Pt and Pd, its cost is significantly reduced, and it has stronger economic adaptability. The nitrogen-doped carbon material as a carrier not only provides abundant surface active sites but also optimizes the electron density of these sites through the electronic effect of nitrogen atoms. These sites promote the loading of high-entropy alloy nanoparticles, improve the surface activity of the high-entropy alloy catalyst, and thus enhance the efficiency of the catalytic reaction.

[0024] 4. In the high-entropy alloy / nitrogen-doped carbon nano-catalytic material of this application, the prepared high-entropy alloy nanoparticles have a small size, so they have a high surface energy. However, the high surface energy easily leads to severe aggregation of high-entropy alloy nanoparticles, significantly reducing their specific surface area and covering a large number of active sites. By loading the high-entropy alloy on the surface of the nitrogen-doped carbon material, the nitrogen-doped carbon can disperse the high-entropy alloy as a supporting carrier, effectively inhibiting the aggregation of the high-entropy alloy, and thus significantly increasing the exposure of active sites. The exposure of a large number of active sites provides more reaction sites for the catalytic reaction, thereby significantly improving the catalytic performance of this novel nano-catalytic material.

[0025] 5. The present application proposes a simple method for preparing a novel nano-catalytic material. This method uses a high-entropy alloy as the main material and nitrogen-doped carbon as the carrier material, and a novel nano-composite material of high-entropy alloy / nitrogen-doped carbon with excellent Fenton-like performance can be prepared through a simple two-step calcination method. Compared with traditional preparation techniques, this method does not require complex equipment and the process operation is simple. At the same time, the obtained material has good dispersibility and exposes active sites. In the field of preparing environmental functional nano-materials, the preparation method provided by the present application shows broad application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0027] Figure 1 It is the scanning transmission electron microscope image of the novel nano-catalytic material of high-entropy alloy / nitrogen-doped carbon in Example 2 of the present application.

[0028] Figure 2 It is the X-ray diffraction pattern of the novel nano-catalytic material of high-entropy alloy / nitrogen-doped carbon in Example 2 of the present application.

[0029] Figure 3 It is the Raman spectrum of the novel nano-catalytic material of high-entropy alloy / nitrogen-doped carbon in Example 2 of the present application.

[0030] Figure 4 It is the performance graph of degrading tetracycline of the novel nano-catalytic materials of high-entropy alloy / nitrogen-doped carbon with different ratios in Examples 1-3 of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The following further describes the present application in conjunction with the accompanying drawings of the specification and specific preferred embodiments, but does not limit the protection scope of the present application thereby.

[0032] The materials and instruments used in the following embodiments are all commercially available.

[0033] A novel nano-catalytic material of high-entropy alloy / nitrogen-doped carbon and its preparation method. The nano-catalytic material includes a high-entropy alloy and nitrogen-doped carbon, wherein the high-entropy alloy is the main material and nitrogen-doped carbon is the carrier material, and the novel nano-catalytic material is prepared by compounding the high-entropy alloy and nitrogen-doped carbon.

[0034] Example 1: A nano-catalytic material of high-entropy alloy / nitrogen-doped carbon includes a high-entropy alloy and nitrogen-doped carbon. The high-entropy alloy is the main material and nitrogen-doped carbon is the carrier material. The high-entropy alloy and nitrogen-doped carbon are compounded to form a novel nano-catalytic material.

[0035] In this embodiment, the mass ratio of the high-entropy alloy to the nitrogen-doped carbon in the high-entropy alloy / nitrogen-doped carbon nanocatalytic material is 1:1.

[0036] A preparation method of the nitrogen-doped carbon-supported non-precious metal high-entropy alloy catalytic material of this embodiment above includes the following steps:

[0037] (1) Accurately weigh 1.12 g of 2-methylimidazole and dissolve it in 5 mL of ultrapure water and ultrasonically form a uniform solution, denoted as solution A; accurately weigh 0.3 g of zinc acetate dihydrate and dissolve it in 5 mL of ultrapure water, denoted as solution B; add solution A to solution B and stir vigorously, let the obtained white solution stand for aging for 24 h, then centrifuge and wash the aged ZIF-8 solution with water and absolute ethanol for 3 - 5 times, and vacuum dry it at 60 °C for 12 h to obtain ZIF-8.

[0038] (2) Place the ZIF-8 obtained in step S1 in a tube furnace, heat it to 1000 °C at a heating rate of 2 °C / min in an Ar atmosphere, and calcine it at 1000 °C for 2 h. After the reaction ends, wash the obtained black powder with water and absolute ethanol for 3 - 5 times, and vacuum dry it at 60 °C for 12 h to obtain nitrogen-doped carbon.

[0039] (3) Accurately weigh 25 mg of nitrogen-doped carbon and ultrasonically disperse it in 44 mL of ethanol solution, then sequentially add 1.1 mL of iron(III) chloride hexahydrate ethanol solution (1 mg / mL), 247 μL of cobalt(II) chloride hexahydrate ethanol solution (25 mg / mL), 247 μL of nickel(II) chloride hexahydrate ethanol solution (25 mg / mL), 140 μL of copper(II) chloride dihydrate ethanol solution (25 mg / mL), and 205 μL of manganese(II) chloride tetrahydrate (25 mg / mL), magnetically stir for 24 h to form a black solution, and rotary evaporate it at 40 °C to obtain a black solid. Place the black solid in a tube furnace, heat it to 1000 °C at a heating rate of 10 °C / min in an Ar atmosphere, and calcine it at 1000 °C for 1 h. After the reaction ends, wash the obtained black powder with water and absolute ethanol for 3 - 5 times, and vacuum dry it at 60 °C for 12 h to obtain the high-entropy alloy / nitrogen-doped carbon nanocatalytic material.

[0040] In the high-entropy alloy / nitrogen-doped carbon nanocatalytic material prepared in this embodiment, the mass ratio of the high-entropy alloy to the nitrogen-doped carbon is 1:1.

[0041] Example 2: A high-entropy alloy / nitrogen-doped carbon nanocatalytic material includes a high-entropy alloy and nitrogen-doped carbon. The high-entropy alloy is the main material and the nitrogen-doped carbon is the carrier material. The high-entropy alloy and nitrogen-doped carbon are compounded to form a novel nanocatalytic material.

[0042] In this embodiment, the mass ratio of the high-entropy alloy to the nitrogen-doped carbon in the high-entropy alloy / nitrogen-doped carbon nanocatalytic material is 1:2.

[0043] A preparation method of the high-entropy alloy / nitrogen-doped carbon nanocatalytic material of the above embodiment includes the following steps:

[0044] (1) Accurately weigh 1.12 g of 2-methylimidazole and dissolve it in 5 mL of ultrapure water and ultrasonically form a uniform solution, denoted as solution A; accurately weigh 0.3 g of zinc acetate dihydrate and dissolve it in 5 mL of ultrapure water, denoted as solution B; add solution A to solution B and stir vigorously, let the obtained white solution stand for aging for 24 h, then centrifuge and wash the aged ZIF-8 solution with water and absolute ethanol for 3-5 times, and vacuum dry it at 60 °C for 12 h to obtain ZIF-8. (2) Place the ZIF-8 obtained in step S1 in a tube furnace, heat it to 1000 °C at a heating rate of 2 °C / min in an Ar atmosphere, and calcine it at 1000 °C for 2 h. After the reaction ends, with a heating rate of 2 °C / min, obtain a black powder, filter and wash the obtained black powder with water and absolute ethanol for 3-5 times, place the washed solid in a vacuum drying oven, dry it at 60 °C for 12 h to obtain nitrogen-doped carbon and vacuum dry it at 60 °C for 12 h to obtain nitrogen-doped carbon.

[0045] (3) Accurately weigh 50 mg of nitrogen-doped carbon and ultrasonically disperse it in 44 mL of ethanol solution, then sequentially add 1.1 mL of iron(III) chloride hexahydrate ethanol solution (1 mg / mL), 247 μL of cobalt(II) chloride hexahydrate ethanol solution (25 mg / mL), 247 μL of nickel(II) chloride hexahydrate ethanol solution (25 mg / mL), 140 μL of copper(II) chloride dihydrate ethanol solution (25 mg / mL), and 205 μL of manganese(II) chloride tetrahydrate (25 mg / mL), magnetically stir for 24 h to form a black solution, and rotary evaporate it at 40 °C to obtain a black solid. Place the black solid in a tube furnace, heat it to 1000 °C at a heating rate of 10 °C / min in an Ar atmosphere, and calcine it at 1000 °C for 1 h. After the reaction ends, wash the obtained black powder with water and absolute ethanol for 3-5 times, and vacuum dry it at 60 °C for 12 h to obtain the high-entropy alloy / nitrogen-doped carbon nanocatalytic material.

[0046] In the high-entropy alloy / nitrogen-doped carbon nanocatalytic material prepared in this embodiment, the mass ratio of the high-entropy alloy to the nitrogen-doped carbon is 1:2.

[0047] Figure 1 It is the scanning electron microscope image of the high-entropy alloy / nitrogen-doped carbon nanocatalytic material in Example 2 of this application. FromFigure 1 It can be seen that the nitrogen-doped carbon is also octahedral, and there are some small nanoparticles attached to its surface. These nanoparticles are non-noble metal high-entropy alloys.

[0048] Figure 2 This is the X-ray diffraction pattern of the high-entropy alloy / nitrogen-doped carbon nanocatalytic material in Example 2 of this application. From Figure 2 it can be seen that the diffraction peaks of both the high-entropy alloy and the nitrogen-doped carbon are contained in this nanocatalytic material.

[0049] Figure 3 This is the Raman spectrum of the high-entropy alloy / nitrogen-doped carbon nanocatalytic material in Example 2 of this application. The gray dotted lines respectively represent the D band and the G band. The D band is related to the defects or disordered structures in the material, and the G band reflects the crystallinity and graphitization degree of the material. I D / I G is used to quantify the defect density of the material. From Figure 3 it can be seen that the ratio of the D band to the G band of the high-entropy alloy / nitrogen-doped carbon nanocatalytic material is larger than that of the nitrogen-doped carbon nanocatalytic material, indicating that there are more defects in the high-entropy alloy / nitrogen-doped carbon nanocatalytic material.

[0050] As described above, it can be proved that the high-entropy alloy / nitrogen-doped carbon nanocatalytic material has been successfully prepared.

[0051] Example 3: A high-entropy alloy / nitrogen-doped carbon nanocatalytic material includes a high-entropy alloy and nitrogen-doped carbon. The high-entropy alloy is the main material, and the nitrogen-doped carbon is the carrier material. The high-entropy alloy and the nitrogen-doped carbon are compounded to form a novel nanocatalytic material.

[0052] In this example, the mass ratio of the high-entropy alloy to the nitrogen-doped carbon in the high-entropy alloy / nitrogen-doped carbon nanocatalytic material is 1:4.

[0053] A preparation method of the high-entropy alloy / nitrogen-doped carbon nanocatalytic material of this example above includes the following steps:

[0054] (1) Accurately weigh 1.12 g of 2-methylimidazole and dissolve it in 5 mL of ultrapure water and ultrasonicate to form a homogeneous solution, denoted as solution A; accurately weigh 0.3 g of zinc acetate dihydrate and dissolve it in 5 mL of ultrapure water, denoted as solution B; add solution A to solution B and stir vigorously. Let the obtained white solution stand for aging for 24 h, and then centrifuge and wash the aged ZIF-8 solution with water and absolute ethanol for 3-5 times, and vacuum dry it at 60 °C for 12 h to obtain ZIF-8.

[0055] (2) Place the ZIF-8 obtained in step S1 in a tubular furnace, heat it to 1000 °C at a heating rate of 2 °C / min in an Ar atmosphere, and calcine it at 1000 °C for 2 h. After the reaction is completed, the heating rate is 2 °C / min to obtain a black powder. The obtained black powder is filtered and washed 3-5 times with water and absolute ethanol. The solid obtained after washing is placed in a vacuum drying oven and dried at 60 °C for 12 h to obtain nitrogen-doped carbon, and then vacuum dried at 60 °C for 12 h to obtain nitrogen-doped carbon.

[0056] (3) Accurately weigh 100 mg of nitrogen-doped carbon and ultrasonically disperse it in 44 mL of ethanol solution. Then, successively add 1.1 mL of a 1 mg / mL iron(III) chloride hexahydrate ethanol solution, 247 μL of a 25 mg / mL cobalt(II) chloride hexahydrate ethanol solution, 247 μL of a 25 mg / mL nickel(II) chloride hexahydrate ethanol solution, 140 μL of a 25 mg / mL copper(II) chloride dihydrate ethanol solution, and 205 μL of a 25 mg / mL manganese(II) chloride tetrahydrate, and magnetically stir for 24 h to form a black solution. Rotate evaporate the black solution at 40 °C to obtain a black solid. Place the black solid in a tubular furnace, heat it to 1000 °C at a heating rate of 10 °C / min in an Ar atmosphere, and calcine it at 1000 °C for 1 h. After the reaction is completed, wash the obtained black powder 3-5 times with water and absolute ethanol, and vacuum dry it at 60 °C for 12 h to obtain a high-entropy alloy / nitrogen-doped carbon nanocatalytic material.

[0057] In the high-entropy alloy / nitrogen-doped carbon nanocatalytic material prepared in this example, the mass ratio of the high-entropy alloy to nitrogen-doped carbon is 1:4.

[0058] Study the influence of the different high-entropy alloy / nitrogen-doped carbon nanocatalytic materials prepared in Examples 1-3 on the degradation efficiency of tetracycline.

[0059] Accurately weigh 10 mg of nitrogen-doped carbon, and high-entropy alloy / nitrogen-doped carbon novel nanocatalytic materials with mass ratios of 1:1, 1:2, and 1:4, and add them to 100 mL of a 10 mg / L tetracycline solution respectively. Under dark conditions, the mixed suspension is stirred on a magnetic stirrer for 30 min to achieve adsorption-desorption equilibrium of tetracycline on different catalyst surfaces. Then, add persulfate to the mixed solution that has reached adsorption equilibrium for a Fenton-like reaction. Sample 1.5 mL of the solution with an organic filter head every 5 min, and the total sampling time is 30 min. After the experiment, use a high-performance liquid chromatograph to test the concentration of tetracycline in the solution and calculate the degradation efficiency of tetracycline. The experimental results are as Figure 4 shown.

[0060] Figure 4Performance graphs of potassium persulfate, nitrogen-doped carbon, and high-entropy alloy / nitrogen-doped carbon novel nanocatalytic materials with mass ratios of 1:1, 1:2, and 1:4 prepared in Examples 1-3 of this application for the degradation of tetracycline. In Figure 4 , from -30 minutes to 0 minutes is the adsorption stage of the material. Since the adsorption time is 30 minutes and the subsequent reaction time is also 30 minutes, if the data is not represented by a breakpoint (“ / / ”), the data in the subsequent reaction stage will not be prominent enough for effective comparison. However, the use of “ / / ” does not affect the adsorption data or the subsequent reaction data, and has no impact on the overall experimental results. From Figure 4 , it can be seen that the degradation of tetracycline by pure potassium persulfate can be ignored, and the degradation performance of the nitrogen-doped carbon monomer for tetracycline is relatively poor, with only x% of tetracycline degraded within 30 minutes. However, the degradation performance of the high-entropy alloy / nitrogen-doped carbon nanocatalytic material for tetracycline is much higher than that of the nitrogen-doped carbon monomer. Moreover, with the increase in the mass of the high-entropy alloy in the nanocatalytic material, the catalytic performance gradually increases. The 1:2 high-entropy alloy / nitrogen-doped carbon nanocatalytic material exhibits the best degradation performance for tetracycline, with approximately 91% of tetracycline being degradable. The increase in the performance of the composite material is because nitrogen-doped carbon can act as a carrier for the high-entropy alloy to disperse the nanoscale high-entropy alloy, preventing its agglomeration and thus exposing more active sites for catalytic reactions. In addition, after the high-entropy alloy and nitrogen-doped carbon are combined, the multiple active centers and excellent electron transport ability of the high-entropy alloy contribute to improving the catalytic performance of the composite material. However, when the content of the high-entropy alloy in the composite material continues to increase, the catalytic performance will decrease because the excessive high-entropy alloy will not be evenly dispersed on the nitrogen-doped carbon carrier, resulting in some active sites being buried and thus reducing the overall catalytic performance. Therefore, the 1:2 high-entropy alloy / nitrogen-doped carbon novel nanocatalytic material has the best degradation effect on tetracycline.

[0061] In summary, the above are only the preferred embodiments of this application and do not impose any formal restrictions on this application. Although this application has been disclosed above with preferred embodiments, it is not intended to limit this application. Any person skilled in the art can make many possible changes and modifications to the technical solution of this application by using the methods and technical content disclosed above, or modify it into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change, and modification made to the above embodiments based on the technical essence of this application without departing from the technical solution of this application still fall within the scope of protection of the technical solution of this application.

Claims

1. A method for preparing a high entropy alloy / nitrogen-doped carbon nanocatalytic material, characterized in that: The high entropy alloy / nitrogen-doped carbon nanocatalytic material comprises a high entropy alloy composed of five non-noble metals, Fe, Co, Ni, Cu and Mn, and nitrogen-doped carbon, wherein the high entropy alloy is loaded on the nitrogen-doped carbon; The mass ratio of the high entropy alloy to the nitrogen-doped carbon in the high entropy alloy / nitrogen-doped carbon nanocatalytic material is 1:1 or 2:1 or 4:1; The preparation method comprises the following steps: S1. Zeolitic imidazolate framework material-8 (ZIF-8) was prepared by coprecipitation method using 2-methylimidazole and zinc acetate dihydrate as precursors; S2. calcining ZIF-8 once to obtain nitrogen-doped carbon; S3. Ferric chloride hexahydrate, cobalt chloride hexahydrate, nickel chloride hexahydrate, cupric chloride dihydrate and manganese chloride tetrahydrate are adsorbed on the surface of nitrogen-doped carbon and a high entropy alloy / nitrogen-doped carbon novel nanocatalytic material is obtained by a secondary calcination method.

2. The method for preparing the high entropy alloy / nitrogen-doped carbon nanocatalytic material according to claim 1, characterized in that: The specific process of step S1 is as follows: 2-methylimidazole is dissolved in ultrapure water and ultrasonically formed into a uniform solution, which is recorded as liquid A; zinc acetate dihydrate is dissolved in ultrapure water and magnetically stirred to form a uniform solution, which is recorded as liquid B; then liquid A is added to liquid B and vigorously stirred, the obtained white solution is allowed to stand for aging, and then the aged ZIF-8 solution is centrifuged and washed several times, and ZIF-8 is obtained after drying.

3. The method for preparing the high entropy alloy / nitrogen-doped carbon nanocatalytic material according to claim 2, characterized in that: In the step S1: the mass of the 2-methylimidazole is 1.12 g, the volume of the ultrapure water is 5 mL, the mass of the zinc acetate dihydrate is 0.3 g, the ultrasonic time is 10 min, the magnetic stirring time is 3 min, the vigorous stirring time is 10 s, the washing number is 3-5 times of alternating washing with water and ethanol, the drying is vacuum drying, the drying temperature is 60° C., and the drying time is 12-24 h.

4. The method for preparing the high entropy alloy / nitrogen-doped carbon nanocatalytic material according to claim 1, characterized in that: The process of step S2 is as follows: the ZIF-8 obtained in step S1 is placed in a tube furnace for calcination, and after the reaction is completed, the obtained black powder is washed and dried to obtain nitrogen-doped carbon.

5. The method for preparing the high entropy alloy / nitrogen-doped carbon nanocatalytic material according to claim 4, characterized in that: In the step S2: the mass of the ZIF-8 is 2 g, the tubular furnace calcination conditions are a calcination temperature of 1000°C, a heating rate of 2°C / min, an Ar environment, a calcination time of 2 h, cleaning is performed by alternating water and ethanol for 3-5 times, drying is performed by vacuum drying, the drying temperature is 60°C, and the drying time is 12-24 h.

6. The method for preparing the high entropy alloy / nitrogen-doped carbon nanocatalytic material according to claim 1, characterized in that: The specific process of step S3 is as follows: dispersing nitrogen-doped carbon in an ethanol solution, adding ethanol solutions of ferric chloride hexahydrate, cobalt chloride hexahydrate, nickel chloride hexahydrate, cupric chloride dihydrate and manganese chloride tetrahydrate to the ethanol solution of nitrogen-doped carbon, stirring magnetically to form a black solution, and then placing the black solid obtained by rotary evaporation in a tubular furnace for secondary calcination. After the reaction is completed, the obtained black powder is washed and dried to obtain a high entropy alloy / nitrogen-doped carbon nanocatalytic material.

7. The method for preparing the high entropy alloy / nitrogen-doped carbon nanocatalytic material according to claim 6, characterized in that: In the step S3, the mass of the nitrogen-doped carbon is 50 mg, the ethanol solution is 44 mL, the concentration of the ferric chloride hexahydrate ethanol solution is 1 mg / mL, the added volume is 1.1 mL, the concentration of the cobalt chloride hexahydrate ethanol solution is 25 mg / mL, the added volume is 247 μL, the concentration of the nickel chloride hexahydrate ethanol solution is 25 mg / mL, the added volume is 247 μL, the concentration of the cupric chloride dihydrate ethanol solution is 25 mg / mL, the added volume is 140 μL, the concentration of the manganese chloride tetrahydrate ethanol solution is 25 mg / mL, the added volume is 205 μL, the magnetic stirring time is 24 h, the rotary evaporation temperature is 40°C, the tubular furnace calcination conditions are calcination temperature of 1000°C, heating rate of 10°C / min, calcination atmosphere is Ar environment, and calcination time is 1 h, the washing is performed by washing with water and ethanol alternately for 3-5 times, the drying is performed by vacuum drying, the drying temperature is 60° C., and the drying time is 12-24 h.

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