A MOF-based NiO@BiFeO3 / C composite material, its preparation method and application

Abstract

The present invention relates to a MOF-based NiO@BiFeO3 / C composite material, a preparation method thereof, and an application thereof. The preparation method comprises the following steps: bismuth salts and iron salts are successively dissolved in an alcohol solvent to form a uniform solution, and then an alkaline precipitant is added, and a precipitation reaction occurs in the solution. After suction filtration, washing, and drying, a bismuth ferrite precursor is obtained; nickel nitrate and 1,3,5-benzenetricarboxylic acid are used for microwave-assisted solvothermal method to obtain MOF-Ni; the bismuth ferrite precursor and MOF-Ni are uniformly mixed and then calcined under an inert gas to obtain the MOF-based NiO@BiFeO3 / C composite material; and it is used as an electrode material in a sodium ion battery. In the present invention, a composite material is prepared by mixing a MOF-based material and a bismuth ferrite precursor and then calcining. The uniformly coated organometallic framework material can effectively activate the electrode material during the charge and discharge process of the battery and improve the electrochemical performance.

Description

Technical Field

[0001] The present invention relates to the technical field of bismuth ferrite composite materials, and particularly relates to a preparation method and application of a MOF-based NiO@BiFeO3 / C composite material. Background Art

[0002] Lithium-ion batteries are one of the most common rechargeable batteries at present and have been widely used in various electronic devices at home and abroad. However, the reserves of metallic lithium on the earth are limited. Sodium-ion batteries are non-toxic, the price of sodium element is low, and the resources are rich, so they are considered to be the most likely candidates to replace traditional lithium-ion batteries.

[0003] Perovskite-type bismuth ferrite (BiFeO3) is the first discovered single-phase multiferroic material with a discharge capacity close to 1000 mAh / g, having a relatively high theoretical capacity and cycling performance. It is widely used in the fields of ferroelectricity, sensing, and photocatalysis. However, there are few reports in the field of sodium-ion batteries. The BiFeO3 crystal has an octahedral structure. There are many reported synthesis methods of BiFeO3, and the obtained product particle size reaches the micron level. However, due to its poor conductivity and fast attenuation, its application is affected. Summary of the Invention

[0004] In order to solve the technical problems of poor conductivity of bismuth ferrite materials and fast capacity attenuation when applied to batteries, a MOF-based NiO@BiFeO3 / C composite material, its preparation method and application are provided. In the present invention, a composite material is obtained by mixing a MOF-based material with a bismuth ferrite precursor and then calcining. The uniformly coated metal-organic framework material can effectively activate the originally nearly insulating electrode material during the charge and discharge process of the battery, thereby improving the conductivity and enhancing the electrochemical performance.

[0005] In order to achieve the above object, the present invention is realized through the following technical solutions:

[0006] A preparation method of a MOF-based NiO@BiFeO3 / C composite material includes the following steps:

[0007] (1) Dissolve bismuth salt and iron salt in an alcohol solvent in sequence to form a uniform solution, then add an alkaline precipitant solution to carry out a precipitation reaction, and obtain a bismuth ferrite precursor after suction filtration, washing, and drying;

[0008] (2) Dissolve nickel nitrate and 1,3,5-benzenetricarboxylic acid in a mixed solution of N,N-dimethylformamide and ethylene glycol with an equal volume ratio, stir evenly, and carry out a microwave-assisted solvothermal reaction at 100-160 °C for 20-120 min. After the reaction ends, cool, wash, and dry to obtain MOF-Ni;

[0009] (3) Mix the bismuth ferrite precursor and the MOF-Ni evenly, and then calcine them at 400-600 °C for 3-5 h under an inert gas to obtain the MOF-based NiO@BiFeO3 / C composite material.

[0010] Further, in step (1), the bismuth salt is bismuth nitrate; the iron salt is one of ferric nitrate, ferric chloride, ferric sulfate, and ferrous sulfate; the alcohol solvent is ethylene glycol; the alkaline precipitating agent solution is one or more of sodium hydroxide solution, ammonia water, and sodium carbonate solution.

[0011] Further, in step (1), the molar ratio of the bismuth salt to the iron salt is 1:(1-1.05); the volume ratio of the total mass of the bismuth salt and the iron salt to the alcohol solvent is (0.6-1) g:50 mL; the addition amount of the alkaline precipitating agent solution is such that the pH value of the reaction system is 9-12.

[0012] Further, in step (2), the dosage ratio of nickel nitrate, 1,3,5-benzenetricarboxylic acid, and the mixed solution is (0.95-1.05) mol:(1.05-1.15) mol:(50-100) L; the power of microwave assistance in step (2) is 1 KW, and the pressure is 1-4 MPa.

[0013] Further, in step (3), the mass ratio of the bismuth ferrite precursor to the MOF-Ni is (1.5-2.8):(2.5-5).

[0014] On the other hand, the present invention provides an MOF-based NiO@BiFeO3 / C composite material prepared by the above preparation method.

[0015] Finally, the present invention provides the application of the MOF-based NiO@BiFeO3 / C composite material prepared by the above preparation method as an electrode material for sodium-ion batteries.

[0016] Beneficial technical effects:

[0017] The MOF-based NiO@BiFeO3 / C composite material of the present invention has the advantages of high specific capacity, high rate performance, and good stability as an electrode material for sodium-ion batteries. By modifying bismuth ferrite with an organic metal framework material, the obtained product has a large specific surface area and high conductivity, which can provide more reaction sites for sodium-ion batteries, increase the reaction contact area, shorten the diffusion distance of sodium ions, make the electrolyte easier to penetrate into the electrode, effectively improve the Coulomb efficiency, increase the charge-discharge plateau, increase the conductivity, and thus effectively slow down the capacity decay, showing good cycling performance and rate performance.

[0018] The MOF-based NiO@BiFeO3 / C composite material of the present invention has good structural stability, a simple preparation method, easy operation, a uniform heating method, and a fast heating rate, which greatly shortens the reaction time, improves the efficiency, and has broad prospects in industrial production applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 XRD pattern of the MOF-based NiO@BiFeO3 / C composite material of Example 1.

[0020] Figure 2 SEM morphology diagrams of the products after calcination of the product of step (2) and the product of step (3) in Example 1, where (a) represents the MOF-based NiO@BiFeO3 / C composite material of the product of step (3), and (b) represents the MOF-based NiO of the product of step (2).

[0021] Figure 3 Constant current cycling efficiency diagram of the sodium-ion battery assembled with the MOF-based NiO@BiFeO3 / C composite material of Example 1 as the electrode material at the current density, (a) is the constant current cycling efficiency diagram at a current density of 200 mA / g, and (b) is the constant current cycling efficiency diagram at a current density of 1000 mA / g.

[0022] Figure 4 Comparison diagram of the rate performance of the MOF-based NiO@BiFeO3 / C composite material of Example 1 and pure BiFeO3 at different current densities. DETAILED DESCRIPTION OF THE INVENTION

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments and drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The description of at least one exemplary embodiment below is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0024] Unless otherwise specifically stated, the numerical values set forth in these embodiments do not limit the scope of the present invention. Techniques and methods known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques and methods should be regarded as part of the specification. In all examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0025] In the following examples, the experimental methods without specific conditions are usually determined according to national standards; if there is no corresponding national standard, they are carried out according to general international standards or the standard requirements proposed by relevant enterprises. Unless otherwise specified, all parts are by weight and all percentages are by weight percentage.

[0026] Example 1

[0027] A preparation method and application of a MOF-based NiO@BiFeO3 / C composite material, comprising the following steps:

[0028] (1) Weigh 0.485 g of bismuth nitrate pentahydrate, add 50 mL of ethylene glycol solution, stir until clear, then add 0.404 g of ferric nitrate nonahydrate. After dissolving for a period of time, adjust the pH value of the reaction system to 9 with 2 mol / L sodium hydroxide solution, a large amount of brownish-black precipitate is produced. After standing for a period of time, filter and wash until neutral to obtain the BiFeO3 precursor.

[0029] (2) Dissolve 0.291 g of nickel nitrate hexahydrate and 0.210 g of 1,3,5-benzenetricarboxylic acid in a mixed solution of 30 mL of DMF and 30 mL of ethylene glycol, stir until evenly mixed, then transfer to a microwave reaction kettle for microwave-assisted solvothermal reaction. The reaction conditions are microwave power 1000 W, pressure 4 MPa, and react at 150 °C for 36 min. After the reaction is completed, cool naturally to room temperature, centrifuge and wash three times with deionized water and ethanol respectively, and dry at 80 °C to obtain MOF-Ni.

[0030] (3) Take 0.248 g of the BiFeO3 precursor and 0.395 g of MOF-Ni, mix them evenly and put them into a porcelain boat for calcination in a tube furnace; the atmosphere in the tube furnace is argon, the calcination temperature is 600 °C, and the calcination time is 3 h. After cooling, a MOF-based NiO@BiFeO3 / C composite material is prepared. At the same time, the product MOF-Ni in step (2) is calcined under the same conditions to obtain MOF-based NiO.

[0031] Perform XRD testing on the product of this example. The XRD pattern is as Figure 1 shown. There are NiO diffraction peaks (corresponding to the PDF#47-1049 standard card) and bismuth ferrite diffraction peaks (corresponding to the PDF#86-1518 standard card) in the product of the MOF-based NiO@BiFeO3 / C composite material. No diffraction peak of carbon is detected. It may be because the carbon content is less than 5 wt% (the XRD detection limit is 5%), or it may be covered by the strong diffraction peak of bismuth ferrite. However, it can still be inferred that there is residual carbon after calcination of MOF-Ni in the composite material.

[0032] The morphology of the final product of this example is as shown in Figure 2 of (a), consisting of Figure 2As shown in (a), MOF-based NiO adheres to the surface of the bismuth ferrite material, forming spherical particles with porous surfaces. Figure 2 As shown in (b), MOF-based NiO is spherical, with a diameter between 1 - 2 μm, a uniform morphology, clear boundaries, and a good shape.

[0033] Example 2

[0034] A preparation method and application of a MOF-based NiO@BiFeO3 / C composite material, comprising the following steps:

[0035] (1) Weigh 0.487 g of bismuth nitrate pentahydrate, add it to 50 mL of ethylene glycol solution, stir until clear, then add 0.270 g of ferric chloride hexahydrate. After dissolving for a period of time, adjust the pH value of the reaction system to 10 with 1 mol / L ammonia water solution, generating a large amount of brownish-black precipitate. After standing for a period of time, filter and wash it until neutral to obtain the BiFeO3 precursor.

[0036] (2) Dissolve 0.292 g of nickel nitrate hexahydrate and 0.242 g of 1,3,5-benzenetricarboxylic acid in a mixture of 35 mL of DMF and 35 mL of ethylene glycol, stir until evenly mixed, then transfer it to a microwave reaction kettle for microwave-assisted solvothermal reaction. The reaction conditions are a microwave power of 1000 W, a pressure of 2.5 MPa, and a reaction at 160 °C for 80 min. After the reaction is completed, naturally cool it to room temperature, centrifuge and wash it three times with deionized water and ethanol respectively, and dry it at 80 °C to obtain MOF-Ni.

[0037] (3) Take 0.212 g of the BiFeO3 precursor and 0.332 g of MOF-Ni, mix them evenly and put them into a porcelain boat for calcination in a tube furnace; the atmosphere in the tube furnace is nitrogen, the calcination temperature is 500 °C, and the calcination time is 5 h. After cooling, the MOF-based NiO@BiFeO3 / C composite material is prepared.

[0038] The XRD pattern of the product in this example is the same as that of the product in Example 1. There are NiO diffraction peaks and bismuth ferrite diffraction peaks in both products. The SEM morphology is similar to that of the product in Example 1. MOF-based NiO adheres to the surface of the bismuth ferrite material, forming spherical particles with porous surfaces.

[0039] Example 3

[0040] A preparation method and application of a MOF-based NiO@BiFeO3 / C composite material, comprising the following steps:

[0041] (1) Weigh 0.486 g of bismuth nitrate pentahydrate, add it to 50 mL of ethylene glycol solution, stir until it becomes clear, then add 0.418 g of ferric sulfate nonahydrate. After dissolving for a period of time, adjust the pH value of the reaction system to 11 with 2 mol / L sodium hydroxide solution, and a large amount of brownish-black precipitate is produced. After standing for a period of time, filter and wash it until it is neutral to obtain the BiFeO3 precursor;

[0042] (2) Dissolve 0.290 g of nickel nitrate hexahydrate and 0.243 g of 1,3,5-benzenetricarboxylic acid in a mixed solution of 30 mL of DMF and 30 mL of ethylene glycol. After stirring until it is evenly mixed, transfer it to a microwave reaction kettle for microwave-assisted solvothermal reaction. The reaction conditions are a microwave power of 1000 W, a pressure of 3 MPa, and a reaction at 120 °C for 60 min. After the reaction is completed, naturally cool it to room temperature, centrifuge and wash it three times with deionized water and ethanol respectively, and dry it at 80 °C to obtain MOF-Ni;

[0043] (3) Take 0.262 g of the BiFeO3 precursor and 0.408 g of MOF-Ni, mix them evenly, put them into a porcelain boat and calcine them in a tubular furnace; the atmosphere in the tubular furnace is nitrogen, the calcination temperature is 400 °C, and the calcination time is 5 h. After cooling, the MOF-based NiO@BiFeO3 / C composite material is prepared.

[0044] The XRD pattern of the product in this example is the same as that of the product in Example 1. There are NiO diffraction peaks and bismuth ferrite diffraction peaks in both products. The SEM morphology is similar to that of the product in Example 1. MOF-based NiO adheres to the surface of the bismuth ferrite material, forming spherical particles with porous surfaces.

[0045] Example 4

[0046] A preparation method and application of a MOF-based NiO@BiFeO3 / C composite material, comprising the following steps:

[0047] (1) Weigh 0.485 g of bismuth nitrate pentahydrate, add it to 50 mL of ethylene glycol solution, stir until it becomes clear, then add 0.170 g of ferrous sulfate monohydrate. After dissolving for a period of time, adjust the pH value of the reaction system to 12 with 2 mol / L sodium hydroxide solution, and a large amount of brownish-black precipitate is produced. After standing for a period of time, filter and wash it until it is neutral to obtain the BiFeO3 precursor;

[0048] (2) Dissolve 0.291 g of nickel nitrate hexahydrate and 0.210 g of 1,3,5-benzenetricarboxylic acid in a mixed solution of 30 mL of DMF and 30 mL of ethylene glycol. After stirring until evenly mixed, transfer it to a microwave reaction kettle for microwave-assisted solvothermal reaction. The reaction conditions are a microwave power of 1000 W, a pressure of 1.5 MPa, and a reaction at 150 °C for 120 min. After the reaction, naturally cool to room temperature, centrifuge and wash three times with deionized water and ethanol respectively, and dry at 80 °C to obtain MOF-Ni;

[0049] (3) Take 0.186 g of the precursor BiFeO3 and 0.295 g of MOF-Ni, mix them evenly and put them into a porcelain boat for calcination in a tube furnace; the atmosphere in the tube furnace is nitrogen, the calcination temperature is 600 °C, and the calcination time is 3 h. After cooling, the MOF-based NiO@BiFeO3 / C composite material is prepared.

[0050] The XRD pattern of the product in this example is the same as that of the product in Example 1. There are NiO diffraction peaks and bismuth ferrite diffraction peaks in the products. The SEM morphology is similar to that of the product in Example 1. MOF-based NiO adheres to the surface of the bismuth ferrite material, forming spherical particles with porous surfaces.

[0051] Comparative Example 1

[0052] The product of this comparative example is pure bismuth ferrite: The preparation of the BiFeO3 precursor is the same as that in step (1) of Example 1. After obtaining the BiFeO3 precursor, grind it into powder and calcine it in a tube furnace. The calcination conditions are the same as those in step (3) of Example 1, that is, a pure bismuth ferrite material is prepared.

[0053] The XRD pattern of the material in this comparative example is as Figure 1 shown, and the phase is the same as the standard card.

[0054] Comparative Example 2

[0055] In the preparation of the product of this comparative example, MOF-Ni was not constructed. The preparation method:

[0056] (1) The preparation of the BiFeO3 precursor is the same as that in step (1) of Example 1;

[0057] (2) Dissolve 0.292 g of nickel nitrate hexahydrate in a mixed solution of 30 mL of deionized water and 30 mL of ethylene glycol. After stirring until evenly mixed, transfer it to a microwave reaction kettle for microwave-assisted solvothermal reaction. The reaction conditions and post-treatment are the same as those in step (2) of Example 1 to obtain the Ni precursor;

[0058] (3) Take the BiFeO3 precursor and the Ni precursor (the molar amount is the same as that in step (3) of Example 1), mix them evenly and put them into a porcelain boat for calcination in a tube furnace. The calcination conditions are the same as those in step (3) of Example 1 to obtain the NiO@BiFeO3 composite material.

[0059] Application Example 1

[0060] The products of the examples and comparative examples were used as electrode materials for sodium-ion batteries, respectively.

[0061] Preparation of the working electrode: The products of the above examples and comparative examples, the conductive agent Super P, and the binder polyvinylidene fluoride were ground according to a mass ratio of 8:1:1, mixed evenly, an appropriate amount of N-methylpyrrolidone was added, and grinding was continued until evenly dispersed. The mixed slurry was evenly coated on a copper foil and vacuum dried at 80 °C for 12 h to obtain the working electrode sheet.

[0062] Using a sodium metal sheet as the counter electrode, a 2016-type button battery was assembled in a glove box filled with argon. The separator was a common Celgard 2250 separator, and the electrolyte was 1 M NaClO4. The assembled button battery was tested for battery performance on a BlueTEC test system. The constant current cycling performance and rate performance of the sodium-ion battery were tested.

[0063] The specific data of the specific capacity, capacity retention rate, and Coulomb efficiency of each battery after cycling 200 times at 200 mA / g and 1000 mA / g are shown in Table 1.

[0064] Table 1 Performance of sodium-ion batteries prepared with the products of examples and comparative examples as electrode materials

[0065]

[0066]

[0067] As can be seen from Table 1, when the MOF-based NiO@BiFeO3 / C composite material of the present invention is used as the electrode material to assemble a button battery, after cycling 200 times at a current density of 200 mA / g, it can maintain a reversible specific capacity of more than 230 mAh / g, a capacity retention rate of more than 30%, and an internal resistance of less than 170 Ω; after cycling 200 times at a current density of 1000 mA / g, it can maintain a reversible specific capacity of more than 280 mAh / g, a capacity retention rate of more than 35%, and an internal resistance of less than 150 Ω.

[0068] Example 1 exhibits excellent performance compared to other examples. Compared with the pure-phase BiFeO3 in Comparative Example 1, the specific capacity increases significantly. The cyclic performance of NiO@BiFeO3 in Comparative Example 2 and the MOF-based NiO@BiFeO3 / C composite material in Example 1 was compared at current densities of 200 mA / g and 1000 mA / g, respectively. The reversible specific capacity of the material in Example 1 of the present invention increased by 20.56% and 35.9%, respectively, and the internal resistance decreased by 47.19% and 71.09%, respectively, indicating that the preparation of the MOF-based NiO@BiFeO3 / C composite material can improve the battery cycle performance more than NiO@BiFeO3 prepared by conventional metal oxide methods as an electrode. The measured resistance values of Example 2, Example 3, and Example 4 as electrodes are slightly larger than those of Example 1; the battery with the product of Example 1 as an electrode has a higher reversible capacity after cycling.

[0069] The constant current cycling performance diagrams of the sodium-ion batteries prepared with the product of Example 1 as the electrode material at current densities of 200 mA / g and 1000 mA / g for 200 cycles are as Figure 3 shown. As can be seen from Figure 3 (b), for the battery with the MOF-based NiO@BiFeO3 / C composite material as the electrode material, the initial discharge specific capacity is 701.9 mAh / g, the initial charge specific capacity is 544.7 mAh / g, the Coulombic efficiency of the first cycle is 77.6%, and the reversible specific capacity of 300.1 mAh / g can be maintained after 200 cycles; Figure 3 (a) shows that at a current density of 200 mA / g, the initial discharge specific capacity is 986.9 mAh / g, the initial charge specific capacity is 731.4 mAh / g, the Coulombic efficiency of the first cycle is 74.11%, and the reversible specific capacity of 247.5 mAh / g is maintained after 200 cycles. For the sodium-ion battery prepared with pure bismuth ferrite in Comparative Example 1 as the electrode material, at a current density of 1000 mA / g, the initial discharge specific capacity is 545 mAh / g, the initial charge specific capacity is 283.4 mAh / g, the Coulombic efficiency of the first cycle is 52%, and the reversible specific capacity of 110.4 mAh / g can be maintained after 200 cycles; at a current density of 200 mA / g, the initial discharge specific capacity is 776.2 mAh / g, the initial charge specific capacity is 425.4 mAh / g, the Coulombic efficiency of the first cycle is 54.8%, and the reversible specific capacity of 135.7 mAh / g can be maintained after 200 cycles. It can be seen that the MOF-based NiO@BiFeO3 / C composite material of the present invention has a high reversible specific capacity.

[0070] The sodium-ion batteries prepared with the product of Example 1 as the electrode material were cycled at current densities of 100 mA / g, 200 mA / g, 500 mA / g, 1000 mA / g, and 100 mA / g for 10 cycles, 10 cycles, 10 cycles, 10 cycles, and 160 cycles respectively. The constant-current cycling performance diagrams are as follows Figure 4 shown. It can be seen from Figure 4 that when cycled at 100 mA / g, 200 mA / g, 500 mA / g, and 1000 mA / g for 10 cycles, 10 cycles, 10 cycles, and 10 cycles respectively, the average reversible specific capacities of the batteries are 1686.5 mAh / g, 762.5 mAh / g, 538.5 mAh / g, and 406.5 mAh / g respectively. As the current density increases, the specific capacity decays to a certain extent; when the current density is restored to 100 mA / g and cycled for 160 cycles, the reversible specific capacity is restored to 573.1 mAh / g. This indicates that the MOF-based NiO@BiFeO3 / C composite material of the present invention has high reversibility and good stability when used as the electrode material for sodium-ion batteries. For the battery with pure BiFeO3 of Comparative Example 1 as the electrode material, when cycled at current densities of 100 mA / g, 200 mA / g, 500 mA / g, and 1000 mA / g for 10 cycles, 10 cycles, 10 cycles, and 10 cycles respectively, the average reversible specific capacities of the batteries are 957.9 mAh / g, 356.6 mAh / g, 241.8 mAh / g, and 170.2 mAh / g respectively. As the current density increases, the specific capacity decays to a greater extent; when the current density is restored to 100 mA / g and cycled for 160 cycles, the reversible specific capacity is restored to 228.1 mAh / g. It can be seen that the MOF-based NiO@BiFeO3 / C composite material of the present invention has high rate performance.

[0071] As mentioned above, the above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered by the protection scope of the present invention.

Claims

1. Application of an MOF-based NiO@BiFeO3 / C composite material in an electrode material for a sodium-ion battery, characterized in that, The preparation method of the MOF-based NiO@BiFeO3 / C composite material comprises the following steps: (1) Dissolve bismuth salt and iron salt in an alcohol solvent in sequence to form a uniform solution, then add an alkaline precipitating agent solution to carry out a precipitation reaction, and obtain a bismuth ferrite precursor after suction filtration, washing and drying; (2) Dissolve nickel nitrate and 1,3,5-benzenetricarboxylic acid in a mixed solution of N,N-dimethylformamide and ethylene glycol with an equal volume ratio, stir evenly, and carry out microwave-assisted solvothermal reaction at 100-160 °C for 20-120 min. After the reaction is completed, cool, wash and dry to obtain MOF-Ni; (3) Mix the bismuth ferrite precursor and the MOF-Ni evenly, and then under an inert gas, calcine at 400-600 °C for 3-5 h to obtain the MOF-based NiO@BiFeO3 / C composite material; In step (3), the mass ratio of the bismuth ferrite precursor to the MOF-Ni is (1.5-2.8):(2.5-5).

2. The application according to claim 1, wherein In step (1), the bismuth salt is bismuth nitrate; the iron salt is one of ferric nitrate, ferric chloride, ferric sulfate, ferrous sulfate; the alcohol solvent is ethylene glycol; the alkaline precipitating agent solution is one or more of sodium hydroxide solution, ammonia water, sodium carbonate solution.

3. The application according to claim 1, characterized in that, In step (1), the molar ratio of the bismuth salt to the iron salt is 1:(1-1.05); the volume ratio of the total mass of the bismuth salt and the iron salt to the alcohol solvent is (0.6-1) g:50 mL; the addition amount of the alkaline precipitating agent solution is such that the pH value of the reaction system is 9-12.

4. The application according to claim 1, wherein, In step (2), the dosage ratio of the nickel nitrate, the 1,3,5-benzenetricarboxylic acid, and the mixed solution is (0.95-1.05) mol:(1.05-1.15) mol:(50-100) L; the power of microwave assistance in step (2) is 1 KW and the pressure is 1-4 MPa.

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