Preparation method of ZIF-67 derived AFeO3 perovskite wave-absorbing material

Abstract

The application relates to a preparation method of a ZIF-67 derived AFeO3 perovskite wave-absorbing material, and relates to a preparation method of an electromagnetic wave absorbing material. The application aims to solve the problems of high density and poor wave-absorbing effect of the oxide perovskite electromagnetic wave absorbing material prepared by the existing method. The application is based on the easy hydrolysis characteristics of the weak coordination bond ZIF-67, controls the precipitation sequence of the hydrolysis process through the different ion potentials, successfully precipitates the A-site ions outside the matrix, simultaneously releases Co 2+ in the solution, introduces Fe 2+ by the reaction with potassium ferrocyanide, prepares an AFeO3 / C composite material by calcination, and obtains excellent electromagnetic wave absorbing performance in the Ku wave band. The oxide perovskite serves as a semiconductor, can effectively weaken the skin effect caused by the high conductive characteristics of the graphitized carbon, and can obtain the ZIF-67 derived AFeO3 perovskite wave-absorbing material.

Description

Technical Field

[0001] This invention relates to a method for preparing an electromagnetic wave absorbing material. Background Technology

[0002] With the rapid development of science and technology, people have invented various electronic microwave devices and widely applied them in various fields of military and daily life. At the same time, the complex electromagnetic environment generated by the operation of these electronic microwave devices has also brought many negative impacts to people's lives. For example, during operation, they will more or less radiate electromagnetic waves, which can harm the human body or interfere with other precision instruments and equipment. In the military, with the iterative development of reconnaissance equipment such as radar, the detection and destruction of targets has become possible. Currently, electromagnetic radiation pollution has become the fourth major public hazard threatening human survival, following air pollution, noise pollution, and water pollution. As people's technological level continues to improve, while pursuing a high quality of life, they inevitably face electromagnetic radiation.

[0003] Therefore, the research and application of electromagnetic absorbing materials to reduce electromagnetic pollution have gradually attracted the attention of scholars. Currently, absorbing materials are widely used in stealth technology and human protection. Among them, the oxide perovskite material ABO3 has gradually gained attention and is being applied to electromagnetic wave absorbing materials due to its unique physicochemical properties. The structure of ABO3 material consists of oxygen octahedrons sharing a vertex oxygen atom, B-site ions filling the octahedrons, and A-site ions filling the octahedral voids. Its structure is stable, but to effectively control its electromagnetic loss capability, doping modification is often required to distort the oxygen octahedrons in the system, effectively adjusting the material's electrical and magnetic properties. However, this modification method has very limited effect on improving the performance of perovskite absorbing materials, and achieving a certain absorption performance often requires an extremely high filling ratio, which is not conducive to the preparation of lightweight and efficient electromagnetic absorbing agents. Therefore, using MOF materials as a matrix and employing a series of methods to derive perovskite / graphitized carbon composite materials is an effective way to reduce density and enhance performance. Furthermore, there are few reports on the preparation of ABO3 composite materials using MOF derivatization. By selecting the derivatization conditions in the MOF precursor, it is possible to achieve multiple heteroatom doping of A and B site ions in the final ABO3 composite material, thereby adjusting its electronic structure and improving its electromagnetic wave absorption performance. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of high density and poor absorption performance of oxide perovskite electromagnetic absorbing materials prepared by existing methods, and to provide a method for preparing ZIF-67 derived AFeO3 perovskite absorbing materials.

[0005] This invention addresses the technical problem of high density and poor absorption performance in current electromagnetic absorbing materials by innovatively introducing the desired A-site element to replace Co in a ZIF-67 solution through etching replacement. 2+ Then through free Co in the solution 2+ Potassium ferrocyanide was precipitated and then self-assembled into an AFeO3 perovskite phase at high temperature to obtain a high-performance electromagnetic wave absorbing composite material.

[0006] This invention leverages the easily hydrolyzed properties of the weakly coordinated ZIF-67 bond to control the precipitation sequence of the hydrolysis process by varying ionic potentials, successfully precipitating La on the outside of the matrix. 3+ At the same time, release Co 2+ In solution, Fe is introduced through its reaction with potassium ferrocyanide. 2+ AFeO3 / C composite material was prepared by calcination. In this structure, the oxide perovskite, as a semiconductor, effectively weakens the skin effect caused by the high conductivity of graphitized carbon. The composite material exhibits excellent electromagnetic wave absorption performance in the Ku band.

[0007] A method for preparing a ZIF-67 derived AFeO3 perovskite microwave absorbing material is specifically carried out according to the following steps:

[0008] I. Preparation of ZIF-67 matrix:

[0009] ① Dissolve the cobalt salt in methanol to obtain a cobalt salt solution;

[0010] ② Dissolve dimethylimidazole in methanol to obtain a dimethylimidazole solution;

[0011] ③ Mix the cobalt salt solution and the dimethylimidazole solution to obtain a mixed solution; let the mixed solution stand to obtain the reaction product; wash the reaction product and then vacuum dry it to obtain the ZIF-67 matrix;

[0012] II. Introducing La into the ZIF-67 matrix 3+ with Fe 2+ Precursor materials:

[0013] ① Dissolve salt A in deionized water to obtain mixed solution I;

[0014] ② Disperse the ZIF-67 matrix in anhydrous ethanol to obtain mixed solution II;

[0015] ③ Mix solution I and solution II thoroughly, let stand, and obtain a solution containing Co. 2+ A mixed solution with a ZIF-67 matrix coated with La(OH)3 precipitate;

[0016] ④ Dissolve potassium ferrocyanide in deionized water to obtain mixed solution III;

[0017] ⑤ Containing Co 2+ The mixed solution of ZIF-67 matrix coated with La(OH)3 precipitate was mixed with mixed solution III, and allowed to stand to obtain the reaction product; the reaction product was washed and then vacuum dried to obtain the La-introduced product. 3+ with Fe 2+ Precursor materials;

[0018] III. High-temperature calcination:

[0019] Will introduce La 3+ with Fe 2+ The precursor material is heated to 600℃~800℃ and then kept at 600℃~800℃ for a period of time to obtain the AFeO3 / C composite material, which is the ZIF-67 derived AFeO3 perovskite microwave absorbing material.

[0020] The principle of this invention:

[0021] The purpose of this invention is to utilize the spontaneous hydrolysis precipitation of ZIF-67 to add A-site elements (La, Sm, and other lanthanides) and replace Co. 2+ Then through free Co in the solution 2+ Potassium ferrocyanide is precipitated and coated on the outside of the matrix. It then spontaneously assembles into a perovskite phase through subsequent high-temperature calcination. The interaction between the derived perovskite phase and graphitized carbon results in improved absorption performance. Furthermore, the synthesized material exists in a fine powder state, exhibiting characteristics such as controllable morphology, simple synthesis, pollution-free synthesis process, and excellent performance.

[0022] This invention obtains an electromagnetic wave absorbing material with high absorption intensity in the Ku band by deriving a perovskite phase as a semiconductor and interacting with graphitized carbon through multiphase synergy.

[0023] Compared with the preparation and synthesis of existing perovskite absorbing materials, the advantages of this invention are:

[0024] The perovskite composite material derived through this method, with its graphitized carbon layer derived from composite organic ligands, perfectly solves the problem of insufficient absorption capacity in perovskite materials. The resulting material is a powder with small and uniform grain size, controllable shape, and no harmful gas emissions during the synthesis process. It has a high degree of crystallinity, stable material structure, and excellent absorption performance. Attached Figure Description

[0025] Figure 1 The image shows an XRD pattern, where curve A is the XRD curve for Z-1, curve B is the XRD curve for Z-2, and curve C is the XRD curve for Z-3. The pattern is verified using the standard PDF card for LaFeO3 (PDF#75-0541).

[0026] Figure 2 SEM image of the ZIF-67 derived AFeO3 perovskite absorbing material prepared in Example 1;

[0027] Figure 3 The curve represents the complex permittivity.

[0028] Figure 4 The curve shows the complex permeability.

[0029] Figure 5 This is the reflection loss curve. Detailed Implementation

[0030] Specific Implementation Method 1: This implementation method describes a preparation method for a ZIF-67 derived AFeO3 perovskite microwave absorbing material, which is specifically completed according to the following steps:

[0031] I. Preparation of ZIF-67 matrix:

[0032] ① Dissolve the cobalt salt in methanol to obtain a cobalt salt solution;

[0033] ② Dissolve dimethylimidazole in methanol to obtain a dimethylimidazole solution;

[0034] ③ Mix the cobalt salt solution and the dimethylimidazole solution to obtain a mixed solution; let the mixed solution stand to obtain the reaction product; wash the reaction product and then vacuum dry it to obtain the ZIF-67 matrix;

[0035] II. Introducing La into the ZIF-67 matrix 3+ with Fe 2+ Precursor materials:

[0036] ① Dissolve salt A in deionized water to obtain mixed solution I;

[0037] ② Disperse the ZIF-67 matrix in anhydrous ethanol to obtain mixed solution II;

[0038] ③ Mix solution I and solution II thoroughly, let stand, and obtain a solution containing Co. 2+ A mixed solution with a ZIF-67 matrix coated with La(OH)3 precipitate;

[0039] ④ Dissolve potassium ferrocyanide in deionized water to obtain mixed solution III;

[0040] ⑤ Containing Co 2+ The mixed solution of ZIF-67 matrix coated with La(OH)3 precipitate was mixed with mixed solution III, and allowed to stand to obtain the reaction product; the reaction product was washed and then vacuum dried to obtain the La-introduced product. 3+ with Fe 2+ Precursor materials;

[0041] III. High-temperature calcination:

[0042] Will introduce La 3+ with Fe 2+ The precursor material is heated to 600℃~800℃ and then kept at 600℃~800℃ for a period of time to obtain the AFeO3 / C composite material, which is the ZIF-67 derived AFeO3 perovskite microwave absorbing material.

[0043] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: the cobalt salt mentioned in step one ① is cobalt nitrate hydrate or cobalt chloride; the molar ratio of the cobalt salt to the volume of methanol in step one ① is (5mmol~10mmol):(40mL~80mL). The other steps are the same as in Specific Implementation Method One.

[0044] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the molar ratio of dimethylimidazole to methanol in step 1 ② is (10 mmol ~ 20 mmol): (40 mL ~ 80 mL). The other steps are the same as in Specific Implementation Method 1 or 2.

[0045] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in the following ways: the volume ratio of the cobalt salt solution to the dimethylimidazole solution in step one ③ is (20 mL to 40 mL):(20 mL to 40 mL); the standing time in step one ③ is 12 h to 24 h; in step one ③, the reaction product is centrifuged and washed 3 to 5 times with anhydrous ethanol, and then vacuum dried at 60 °C to 70 °C for 10 h to 12 h to obtain the ZIF-67 matrix. Other steps are the same as in Specific Implementation Methods One to Three.

[0046] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: the salt A mentioned in step two ① is La(NO3)3·6H2O or Sm(NO3)3·6H2O; the mass ratio of the salt A mentioned in step two ① to the volume ratio of deionized water is 1 mmol:(20 mL to 40 mL). The other steps are the same as in Specific Implementation Methods One to Four.

[0047] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that: the mass ratio of ZIF-67 matrix to salt A in step two ② is (100mg~300mg):1mmol; the mass ratio of ZIF-67 matrix to anhydrous ethanol in step two ② is (100mg~300mg):(10mL~30mL). The other steps are the same as in Specific Implementation Methods One to Five.

[0048] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: the volume ratio of mixed solution I and mixed solution II in step two ③ is 1:1; the standing time in step two ③ is 6h to 24h. Other steps are the same as in Specific Implementation Methods One to Six.

[0049] Specific Implementation Method Eight: The difference between this implementation method and Specific Implementation Methods One to Seven is that: the volume ratio of potassium ferrocyanide to deionized water in step two ④ is (100mg~300mg):(10mL~30mL); the Co-containing... 2+ The volume ratio of the mixed solution of the ZIF-67 matrix coated with La(OH)3 precipitate to mixed solution III is 2:1; the standing time in step II.⑤ is 30 min to 60 min; in step II.⑤, the precipitate is washed 3 to 5 times with anhydrous ethanol, and then vacuum dried at 60℃ to 70℃ for 10 h to 12 h to obtain the La-introduced product. 3+ with Fe 2+ The precursor material. Other steps are the same as in embodiments one through seven.

[0050] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: the heating rate in step three is 5°C / min; the holding time in step three is 180min. Other steps are the same as in Specific Implementation Methods One to Eight.

[0051] Specific Implementation Method Ten: The difference between this implementation method and Specific Implementation Methods One to Nine is that the ZIF-67 derived AFeO3 perovskite absorbing material is used as an electromagnetic wave absorbing material. The other steps are the same as in Specific Implementation Methods One to Nine.

[0052] The beneficial effects of the present invention are verified using the following embodiments:

[0053] Example 1: A method for preparing a ZIF-67 derived AFeO3 perovskite microwave absorbing material (Z-3), specifically completed according to the following steps:

[0054] I. Preparation of ZIF-67 matrix:

[0055] ① Dissolve 5 mmol of Co(NO3)2·6H2O in 40 mL of methanol to obtain a cobalt salt solution;

[0056] ② Dissolve 20 mmol of dimethylimidazole in 80 mL of methanol to obtain a dimethylimidazole solution;

[0057] ③ Mix the cobalt salt solution and dimethylimidazole solution and stir for 10 min to obtain a mixed solution; let the mixed solution stand for 24 h to obtain the reaction product; wash the reaction product three times with anhydrous ethanol and then vacuum dry at 60 °C for 12 h to obtain the ZIF-67 matrix.

[0058] II. Introducing La into the ZIF-67 matrix 3+ with Fe 2+ Precursor materials:

[0059] ① Dissolve 0.5 mmol of La(NO3)3·6H2O in 20 mL of deionized water to obtain mixed solution I;

[0060] ② Disperse 100 mg of ZIF-67 matrix in 20 mL of anhydrous ethanol to obtain mixed solution II;

[0061] ③ Mix solution I and solution II thoroughly, let stand for 24 hours, and obtain a solution containing Co. 2+ A mixed solution with a ZIF-67 matrix coated with La(OH)3 precipitate;

[0062] The volume ratio of mixed solution I and mixed solution II mentioned in step 2③ is 1:1;

[0063] ④ Dissolve 100 mg of potassium ferrocyanide in 10 mL of deionized water to obtain mixed solution III;

[0064] ⑤ Containing Co 2+ The mixed solution of ZIF-67 matrix coated with La(OH)3 precipitate was mixed with mixed solution III and allowed to stand for 1 h to obtain the reaction product; the reaction product was washed three times with anhydrous ethanol and then dried under vacuum at 60 °C for 12 h to obtain the La-introduced product. 3+ with Fe 2+ Precursor materials;

[0065] The Co-containing component mentioned in step 2.5 2+ The volume ratio of the mixed solution of ZIF-67 matrix coated with La(OH)3 precipitate to mixed solution III is 2:1;

[0066] III. High-temperature calcination:

[0067] Will introduce La 3+ with Fe 2+ The precursor material was heated to 700℃ at a heating rate of 5℃ / min, and then held at 700℃ for 180min to obtain the AFeO3 / C composite material, which is the ZIF-67 derived AFeO3 perovskite microwave absorbing material (Z-3).

[0068] Example 2: The preparation method of Z-1 electromagnetic wave absorbing material is specifically carried out according to the following steps:

[0069] I. Preparation of ZIF-67 matrix:

[0070] ① Dissolve 5 mmol of Co(NO3)2·6H2O in 40 mL of methanol to obtain a cobalt salt solution;

[0071] ② Dissolve 20 mmol of dimethylimidazole in 80 mL of methanol to obtain a dimethylimidazole solution;

[0072] ③ Mix the cobalt salt solution and dimethylimidazole solution and stir for 10 min to obtain a mixed solution; let the mixed solution stand for 24 h to obtain the reaction product; wash the reaction product three times with anhydrous ethanol and then vacuum dry at 60 °C for 12 h to obtain the ZIF-67 matrix.

[0073] 2. The ZIF-67 matrix is ​​heated to 700℃ at a heating rate of 5℃ / min, and then held at 700℃ for 180min to obtain Z-1.

[0074] Example 3: The preparation method of Z-2 electromagnetic wave absorbing material is specifically carried out according to the following steps:

[0075] I. Preparation of ZIF-67 matrix:

[0076] ① Dissolve 5 mmol of Co(NO3)2·6H2O in 40 mL of methanol to obtain a cobalt salt solution;

[0077] ② Dissolve 20 mmol of dimethylimidazole in 80 mL of methanol to obtain a dimethylimidazole solution;

[0078] ③ Mix the cobalt salt solution and dimethylimidazole solution and stir for 10 min to obtain a mixed solution; let the mixed solution stand for 24 h to obtain the reaction product; wash the reaction product three times with anhydrous ethanol and then vacuum dry at 60 °C for 12 h to obtain the ZIF-67 matrix.

[0079] II. Introducing La into the ZIF-67 matrix 3+ with Fe 2+ Precursor materials:

[0080] ① Dissolve 0.5 mmol of La(NO3)3·6H2O in 20 mL of deionized water to obtain mixed solution I;

[0081] ② Disperse 100 mg of ZIF-67 matrix in 20 mL of anhydrous ethanol to obtain mixed solution II;

[0082] ③ Mix solution I and solution II thoroughly, let stand for 24 hours, and obtain a solution containing Co. 2+ A mixed solution of ZIF-67 matrix coated with La(OH)3 precipitate; using anhydrous ethanol to treat Co-containing... 2+ The mixture of the ZIF-67 matrix coated with La(OH)3 precipitate was centrifuged and washed three times, then vacuum dried at 60℃ for 12 h to obtain the product incorporating La. 3+ Precursor materials;

[0083] The volume ratio of mixed solution I and mixed solution II mentioned in step 2③ is 1:1;

[0084] III. Introducing La 3+ The precursor material was heated to 700℃ at a heating rate of 5℃ / min, and then held at 700℃ for 180min to obtain Z-2.

[0085] Figure 1 The image shows an XRD pattern, where curve A is the XRD curve for Z-1, curve B is the XRD curve for Z-2, and curve C is the XRD curve for Z-3. The pattern is verified using the standard PDF card for LaFeO3 (PDF#75-0541).

[0086] Depend on Figure 1 It can be seen that after calcination at 700℃, ZIF-67 exhibits obvious Co elemental diffraction peaks, proving that after high-temperature calcination, most of the Co in ZIF-67 is converted into Co. 2+ It is reduced to Co by carbon. La is then introduced. 3+ The precursor material, after calcination, mainly exhibits diffraction peaks of La(OH)3, proving that most of the Co inside the matrix... 2+ La 3+ The substitution of La, and the absence of a corresponding diffraction peak for Co, indicates that it exists primarily in ionic form in solution. 3+ with Fe 2+ The precursor material exhibited diffraction peaks of LaFeO3 after calcination, proving that the LaFeO3 phase composite electromagnetic wave absorbing material was successfully prepared through two precipitation processes.

[0087] Figure 2 SEM image of the ZIF-67 derived AFeO3 perovskite absorbing material prepared in Example 1;

[0088] Depend on Figure 2 It can be observed that the introduction of La into the ZIF-67 matrix... 3+ with Fe 2+ After being prepared as a precursor material and hydrolyzed, its morphology is irregular, the original matrix structure is destroyed, and it is converted into a particulate precipitate.

[0089] The ZIF-67-derived AFeO3 perovskite microwave absorbing material prepared in Example 1 was mixed with paraffin at a mass ratio of 4:6. Cyclohexane was then added and the mixture was uniformly mixed at 70°C. After drying, the mixture was pressed into paraffin rings with an inner diameter of 3.04 mm, an outer diameter of 7 mm, and a thickness of 2 mm using a mold to obtain the microwave absorbing agent. The mass-to-volume ratio of the ZIF-67-derived AFeO3 perovskite microwave absorbing material, paraffin, and cyclohexane prepared in Example 1 was 500 mg:500 mg:1 mL. The electromagnetic properties of the microwave absorbing agent were tested, see [see details]. Figures 3-5 As shown;

[0090] The complex permittivity curves of the microwave absorber at frequencies from 2 to 18 GHz, measured using a vector network analyzer, are shown below. Figure 3 As shown;

[0091] Figure 3 The curve represents the complex permittivity.

[0092] Depend on Figure 3 It can be seen that in the AFeO3 perovskite microwave absorbing material derived from ZIF-67 matrix, the real part of the dielectric constant decreases with increasing frequency, ranging from 17 to 11.4. The imaginary part decreases with increasing frequency, ranging from 5.8 to 3.3.

[0093] The permeability curves of the absorbing agent at frequencies of 2–18 GHz were obtained using a vector network analyzer, as shown below. Figure 4 As shown;

[0094] Figure 4 The curve shows the complex permeability.

[0095] Depend on Figure 4 It can be seen that the real part of the perovskite microwave absorbing material derived from ZIF-67 matrix exhibits little change with frequency, mainly fluctuating around 1, which is consistent with the antiferromagnetic phase composition. The imaginary part, however, fluctuates within the range of 0.01-0.13 with frequency.

[0096] Compared to perovskite microwave absorbing materials prepared by traditional methods, this invention uses metal nodes provided by MOFs materials themselves to combine with the desired perovskite A-site elements. Through multiple precipitation processes and high-temperature calcination, a new perovskite phase is self-assembled. The resulting material can achieve excellent dielectric and magnetic loss capabilities at a filling ratio of 50 wt%.

[0097] The absorption performance of absorbing materials of different thicknesses in the frequency range of 2-18GHz is as follows: Figure 5 As shown;

[0098] Figure 5 This is the reflection loss curve;

[0099] Depend on Figure 5It can be seen that the absorption peak center of the AFeO3 perovskite absorbing material (Z-3) derived from ZIF-67 is located at 16.5GHz, and the lowest reflection loss value reaches -60.1dB, which is better than almost all existing perovskite materials.

Claims

1. A method for preparing a ZIF-67 derived AFeO3 perovskite microwave absorbing material, characterized in that... The preparation method is specifically carried out according to the following steps: I. Preparation of ZIF-67 matrix: ① Dissolve the cobalt salt in methanol to obtain a cobalt salt solution; The cobalt salt mentioned in step 1① is cobalt nitrate hydrate or cobalt chloride; The molar ratio of cobalt salt to methanol in step 1① is (5mmol~10mmol):(40mL~80mL); ②, dissolve dimethylimidazole in methanol to obtain a dimethylimidazole solution; ③ Mix the cobalt salt solution and the dimethylimidazole solution to obtain a mixed solution; let the mixed solution stand to obtain the reaction product; wash the reaction product and then vacuum dry it to obtain the ZIF-67 matrix; II. Introducing La into the ZIF-67 matrix 3+ with Fe 2+ Precursor materials: ① Dissolve salt A in deionized water to obtain mixed solution I; The salt A mentioned in step 2① is La(NO3)3·6H2O or Sm(NO3)3·6H2O; In step 2①, the mass ratio of salt A to deionized water is 1 mmol:(20 mL ~ 40 mL). ② Disperse the ZIF-67 matrix in anhydrous ethanol to obtain mixed solution II; The mass ratio of ZIF-67 matrix to salt A mentioned in step 2② is (100mg~300mg):1mmol; The mass ratio of ZIF-67 matrix to anhydrous ethanol in step 2② is (100mg~300mg):(10mL~30mL); ③ Mix solution I and solution II thoroughly, let stand, and obtain a solution containing Co. 2+ A mixed solution with a ZIF-67 matrix coated with La(OH)3 precipitate; ④ Dissolve potassium ferrocyanide in deionized water to obtain mixed solution III; The volume ratio of potassium ferrocyanide to deionized water mentioned in step 2④ is (100mg~300mg):(10mL~30mL); ⑤ Containing Co 2+ The mixed solution of ZIF-67 matrix coated with La(OH)3 precipitate was mixed with mixed solution III, and allowed to stand to obtain the reaction product; the reaction product was washed and then vacuum dried to obtain the La-introduced product. 3+ with Fe 2+ Precursor materials; The Co-containing component mentioned in step 2.5 2+ The volume ratio of the mixed solution of ZIF-67 matrix coated with La(OH)3 precipitate to mixed solution III is 2:1; III. High-temperature calcination: Will introduce La 3+ with Fe 2+ The precursor material is heated to 600℃~800℃ and then kept at 600℃~800℃ for a period of time to obtain AFeO3 / C composite material, which is ZIF-67 derived AFeO3 perovskite microwave absorbing material. The heating rate described in step three is 5℃ / min; the holding time described in step three is 180min.

2. The preparation method of a ZIF-67 derived AFeO3 perovskite microwave absorbing material according to claim 1, characterized in that... The molar ratio of dimethylimidazole to methanol in step 1② is (10mmol~20mmol):(40mL~80mL).

3. The preparation method of a ZIF-67 derived AFeO3 perovskite microwave absorbing material according to claim 1, characterized in that... The volume ratio of the cobalt salt solution to the dimethylimidazole solution in step 1③ is (20mL~40mL):(20mL~40mL); the standing time in step 1③ is 12h~24h; in step 1③, the reaction product is centrifuged and washed 3~5 times with anhydrous ethanol, and then vacuum dried at 60℃~70℃ for 10h~12h to obtain the ZIF-67 matrix.

4. The preparation method of a ZIF-67 derived AFeO3 perovskite microwave absorbing material according to claim 1, characterized in that... The volume ratio of mixed solution I and mixed solution II mentioned in step 2③ is 1:1; the standing time mentioned in step 2③ is 6h~24h.

5. The preparation method of a ZIF-67 derived AFeO3 perovskite microwave absorbing material according to claim 1, characterized in that... The settling time mentioned in step 2.5 is 30 min to 60 min; in step 2.5, the precipitate is washed 3 to 5 times with anhydrous ethanol, and then vacuum dried at 60℃ to 70℃ for 10 h to 12 h to obtain the La-introduced product. 3+ with Fe 2+ Precursor materials.

6. The method for preparing a ZIF-67 derived AFeO3 perovskite microwave absorbing material according to claim 1, characterized in that... The ZIF-67 derived AFeO3 perovskite absorbing material is used as an electromagnetic wave absorbing material.

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