A bimetallic iron-zirconium framework composite material, its preparation method and application

Abstract

This invention discloses an iron-zirconium bimetallic organic framework composite material, its preparation method, and its applications. The raw materials for the iron-zirconium bimetallic organic framework composite material include zirconium tetrachloride, methyl-4-tetra(4-carboxyphenyl)porphyrin, benzoic acid, and an iron salt. Zirconium tetrachloride, methyl-4-tetra(4-carboxyphenyl)porphyrin, and benzoic acid undergo a hydrothermal reaction in an organic solvent to obtain a zirconium-based metal-organic framework material. The mass ratio of zirconium tetrachloride, methyl-4-tetra(4-carboxyphenyl)porphyrin, and benzoic acid is 2.4–2.6:1:58–62. The zirconium-based metal-organic framework material is then reacted with the iron salt in an organic solvent to obtain the iron-zirconium bimetallic organic framework composite material. The mass ratio of the zirconium-based metal-organic framework material to the iron salt is 0.9–1.1:1. The iron-zirconium bimetallic organic framework composite material prepared by this invention has a stable and reliable structure and exhibits excellent catalytic performance in catalyzing CO2 rings. It can be recycled multiple times in the reaction system without frequent replacement.

Description

Technical Field

[0001] This invention relates to the field of catalytic material preparation and application, and more specifically, to an iron-zirconium bimetallic organic framework composite material, its preparation method, and its application. Background Technology

[0002] Currently, carbon dioxide (CO2) has become one of the largest greenhouse gases emitted, and its excessive emissions have led to severe greenhouse effects and global warming. Therefore, there is an urgent need to reduce the ever-increasing CO2 concentration in the atmosphere through CO2 capture and conversion. However, due to the thermodynamic stability and kinetic inertia of CO2, achieving its efficient conversion and resource utilization faces new challenges.

[0003] Among various CO2 conversion pathways, the cycloaddition reaction of CO2 with epoxides to form cyclic carbonates is considered an ideal strategy for CO2 conversion due to its 100% atom utilization rate. This method has enormous potential and has become a focus of research. Furthermore, the cyclic carbonates produced by this reaction are stable, non-toxic, and harmless, making them valuable as green solvents, lithium battery electrolytes, and important intermediates for the synthesis of polymers and chemicals.

[0004] Currently, many homogeneous catalysts have been used for the cycloaddition reaction of CO2, including ionic liquids, quaternary ammonium salts, transition metal complexes, and alkali metal halides. However, a major limitation of homogeneous catalysts is their easy dissolution in the reaction system, leading to difficulties in separation from the reaction phase, low catalyst recovery efficiency, and consequently, resource waste. Therefore, developing efficient and recyclable heterogeneous catalysts for CO2 conversion is particularly important. These catalysts can be separated and recovered after the reaction by simple filtration or precipitation, although their catalytic activity may be lower than that of homogeneous catalysts.

[0005] Metal-organic frameworks (MOFs), as porous materials with remarkable properties, have attracted widespread attention due to their tunable porous structure, high specific surface area, excellent porosity, and strong adsorption capacity. These properties enable MOFs to perform well in various applications such as gas storage and separation, chemical sensing, heterogeneous catalysis, and drug delivery. In recent years, various MOF materials have been attempted to be applied in the field of carbon dioxide cycloaddition. Chinese patent CN104785209A describes a metal-organic framework material composed of zinc halide, a nitrogen-rich ligand of mirtazapurine, and isonicotinic acid, which can achieve similar effects. However, it requires heating to 100 degrees Celsius to achieve the desired effect, increasing energy costs. Chinese patent CN109054043A describes a Y(III)-based hexanuclear rare-earth cluster metal-organic framework material, which requires 36 hours of reaction to achieve a 98% yield at room temperature, resulting in high time costs and relatively low efficiency. The boron-zirconium metal-organic framework material UiO-67-B mentioned in Chinese patent CN114479100A has a preparation process that takes more than 70 hours, and the reaction yield is less than 90% after 6 hours. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an iron-zirconium bimetallic organic framework composite material, its preparation method, and its application. The iron-zirconium bimetallic organic framework composite material is prepared using zirconium tetrachloride, meso-tetra(4-carboxyphenyl)porphyrin, benzoic acid, and iron salt as raw materials. This material has a stable and reliable structure and exhibits excellent catalytic performance in catalyzing CO2 rings. It can be recycled multiple times in the reaction system without frequent replacement.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The first aspect of the present invention provides an iron-zirconium bimetallic organic framework composite material, the raw materials of which include zirconium tetrachloride, medium-tetra(4-carboxyphenyl)porphyrin, benzoic acid and iron salt;

[0009] The zirconium tetrachloride, methyl-tetra(4-carboxyphenyl)porphyrin, and benzoic acid are reacted hydrothermally in an organic solvent to obtain a zirconium-based metal-organic framework material, wherein the mass ratio of zirconium tetrachloride, methyl-tetra(4-carboxyphenyl)porphyrin, and benzoic acid is 2.4-2.6:1:58-62.

[0010] The zirconium-based metal-organic framework material is reacted with the iron salt in an organic solvent to obtain an iron-zirconium bimetallic organic framework composite material; the mass ratio of the zirconium-based metal-organic framework material to the iron salt is 0.9 to 1.1:1.

[0011] Preferably, the iron salt is ferric nitrate nonahydrate.

[0012] Preferably, the organic solvent is N,N-dimethylformamide.

[0013] A second aspect of the present invention provides a method for preparing an iron-zirconium bimetallic organic framework composite material, comprising the following steps:

[0014] S1, zirconium tetrachloride, methyl-4-tetra(4-carboxyphenyl)porphyrin and benzoic acid are dissolved in N,N-dimethylformamide and stirred at room temperature until completely dissolved. The solution is then transferred to a stainless steel high-pressure reactor and subjected to hydrothermal reaction in an oven.

[0015] S2, after the hydrothermal reaction products have cooled naturally, they are washed and dried to obtain zirconium-based metal-organic framework materials;

[0016] S3, the zirconium-based metal-organic framework material and ferric nitrate nonahydrate are dissolved in N,N-dimethylformamide, then transferred to a round-bottom flask, nitrogen gas is introduced to bubble the solution, then heated and stirred in an oil bath, and the reaction product is washed after natural cooling to obtain the iron-zirconium bimetallic organic framework composite material.

[0017] Preferably, in step S1:

[0018] The mass ratio of zirconium tetrachloride, methyl-tetra(4-carboxyphenyl)porphyrin, and benzoic acid is 2.4–2.6:1:58–62.

[0019] The total mass ratio of zirconium tetrachloride, methyl-tetra(4-carboxyphenyl)porphyrin, and benzoic acid to the volume ratio of N,N-dimethylformamide is 1.2–1.32 g: 8 mL.

[0020] Preferably, in step S1:

[0021] The stirring and dissolving time is 30 ± 5 min;

[0022] The stainless steel high-pressure reactor is lined with polytetrafluoroethylene.

[0023] During the hydrothermal reaction process, the oven temperature is 120±10℃, and the hydrothermal reaction time is more than 12 hours.

[0024] Preferably, in step S2:

[0025] During the washing process, the hydrothermal reaction products are centrifuged and washed with N,N-dimethylformamide and methanol, respectively.

[0026] The drying process is carried out in a vacuum oven at a temperature of 60–70°C.

[0027] Preferably, in step S3:

[0028] The mass ratio of the zirconium-based metal-organic framework material to the ferric nitrate nonahydrate is 0.9–1.1:1;

[0029] The total mass ratio of the zirconium-based metal-organic framework material and the ferric nitrate nonahydrate to the total volume ratio of the N,N-dimethylformamide is 96-104 mg: 6 mL.

[0030] Preferably, in step S3:

[0031] The bubble treatment time is 30 minutes or more;

[0032] The temperature of the oil bath is 100-120℃, and the heating and stirring time is more than 5 hours.

[0033] A third aspect of the present invention provides the application of the iron-zirconium bimetallic organic framework composite material as described in the first aspect of the present invention in the photocatalytic CO2 cycloaddition reaction.

[0034] Preferably, the iron-zirconium bimetallic organic framework composite material is activated in a vacuum environment;

[0035] The activated iron-zirconium bimetallic organic framework composite material was added to a reactor containing epichlorohydrin and tetrabutylammonium bromide, CO2 was introduced, and a xenon lamp was used as the light source to carry out a CO2 cycloaddition reaction.

[0036] The beneficial effects of this invention are as follows:

[0037] The iron-zirconium bimetallic organic framework composite material prepared in this invention exhibits excellent catalytic performance. It is mainly synthesized from zirconium tetrachloride, meso-tetra(4-carboxyphenyl)porphyrin, and iron salt. The meso-tetra(4-carboxyphenyl)porphyrin, a porphyrin-like substance, has a stable structure, and the porphyrin structure formed by combining it with zirconium tetrachloride is also very stable and reliable. The introduction of inexpensive iron salt metal can greatly improve the effect and maintain stability. Even after five reaction cycles, its catalytic activity remains above 88%, maintaining its high efficiency and stability. This characteristic is crucial for industrial applications because it means that the catalyst can be recycled multiple times in the reaction system without frequent replacement, thereby reducing production costs and improving the economic efficiency and sustainability of the entire process. In addition, the introduction of iron metal element into this iron-zirconium bimetallic organic framework composite material significantly reduces the cost compared to other materials that introduce precious metal elements with equivalent effects. Attached Figure Description

[0038] Figure 1 This is a flowchart of the preparation method of the iron-zirconium bimetallic organic framework composite material of the present invention;

[0039] Figure 2The XRD patterns are those of the zirconium-based metal-organic framework material and the iron-zirconium bimetallic organic framework composite material prepared in Example 1 of this invention. Detailed Implementation

[0040] To better understand the above-mentioned technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0041] The iron-zirconium bimetallic organic framework composite material of the present invention comprises zirconium tetrachloride, methyl-tetra(4-carboxyphenyl)porphyrin, benzoic acid, and iron salt as raw materials; zirconium tetrachloride, methyl-tetra(4-carboxyphenyl)porphyrin, and benzoic acid are reacted hydrothermally in an organic solvent to obtain a zirconium-based metal-organic framework material, wherein the mass ratio of zirconium tetrachloride, methyl-tetra(4-carboxyphenyl)porphyrin, and benzoic acid is 2.4-2.6:1:58-62; the zirconium-based metal-organic framework material is reacted with the iron salt in an organic solvent to obtain the iron-zirconium bimetallic organic framework composite material; wherein the mass ratio of the zirconium-based metal-organic framework material to the iron salt is 0.9-1.1:1.

[0042] The iron salt mentioned above is ferric nitrate nonahydrate.

[0043] The organic solvent used above is N,N-dimethylformamide.

[0044] The preparation method of the above-mentioned iron-zirconium bimetallic organic framework composite material includes the following steps:

[0045] S1, zirconium tetrachloride, methyl-4-tetra(4-carboxyphenyl)porphyrin and benzoic acid are dissolved in N,N-dimethylformamide and stirred at room temperature until completely dissolved. The solution is then transferred to a stainless steel high-pressure reactor and subjected to hydrothermal reaction in an oven.

[0046] In this step, zirconium tetrachloride, methyl-4-tetra(4-carboxyphenyl)porphyrin, and benzoic acid are dissolved in N,N-dimethylformamide at a mass ratio of 2.4–2.6:1:58–62. The solution is stirred at room temperature for 30 ± 5 min until completely dissolved. The dissolved solution is then transferred to a stainless steel high-pressure reactor lined with polytetrafluoroethylene (PTFE) and subjected to a hydrothermal reaction at 120 ± 10 °C in an oven for at least 12 h. The total mass ratio of zirconium tetrachloride, methyl-4-tetra(4-carboxyphenyl)porphyrin, and benzoic acid to N,N-dimethylformamide is 1.2–1.32 g:8 mL.

[0047] The hydrothermal reaction principle described above is as follows: hydrothermal synthesis of nanomaterials results in high purity, well-developed crystals, low agglomeration, and narrow particle size distribution, avoiding impurities and structural defects caused by post-processing such as high-temperature calcination or ball milling. It can prepare single crystals, thin films, and nanoparticles with different morphologies, as well as new materials, new structures, and metastable phases. Zirconium tetrachloride is introduced as zirconium metal to construct zirconium-based materials. Benzoic acid acts as a linker to break and connect the tetracarboxyl groups of 1,4-tetra(4-carboxyphenyl)porphyrin, stacking them in a layered manner to form a cubic structure. The amount of benzoic acid used can control the size and shape of the synthesized material. N,N-dimethylformamide acts as a solvent and does not participate in the reaction, but it can dissolve the above components together for reaction.

[0048] S2, after the hydrothermal reaction products have cooled naturally, they are washed and dried to obtain zirconium-based metal-organic framework materials;

[0049] In this step, after the hydrothermal reaction product cools naturally to room temperature, the hydrothermal reaction product is centrifuged and washed with N,N-dimethylformamide and methanol, respectively. Specifically, it is stirred with N,N-dimethylformamide for more than 30 minutes, centrifuged and washed, and then fresh N,N-dimethylformamide is added and centrifuged and washed once more in the same manner. Subsequently, the product is transferred and centrifuged and washed with methanol for 1-2 hours, and then stirred with fresh methanol for more than 12 hours. After that, the centrifuged and washed material is placed in a vacuum oven at 60-70°C to dry, thus obtaining zirconium-based metal-organic framework material.

[0050] S3, zirconium-based metal-organic framework material and ferric nitrate nonahydrate were dissolved in N,N-dimethylformamide, then transferred to a round-bottom flask, and nitrogen gas was introduced to bubble the solution. The solution was then heated and stirred in an oil bath. After the reaction product cooled naturally, it was washed to obtain the iron-zirconium bimetallic organic framework composite material.

[0051] In this step, the zirconium-based metal-organic framework material obtained in step S2 and ferric nitrate nonahydrate are dissolved in N,N-dimethylformamide at a mass ratio of 0.9–1.1:1, wherein the total mass ratio of the zirconium-based metal-organic framework material and ferric nitrate nonahydrate to the total volume ratio of N,N-dimethylformamide is 96–104 mg: 6 mL. The solutions are then transferred to a round-bottom flask, and nitrogen gas is introduced to induce bubbling in the solution for at least 30 minutes. The solution is then heated under reflux and stirred in an oil bath at 100–120 °C for at least 5 hours. After the reaction product has cooled naturally to room temperature, the resulting material is washed as described in step S2 to obtain the iron-zirconium bimetallic organic framework composite material.

[0052] In the above steps, ferric nitrate nonahydrate and zirconium-based metal-organic framework materials are dissolved in an organic solvent, and then foamed with nitrogen to remove dissolved oxygen from the mixed solution and prevent it from participating in the reaction and oxidizing the iron. Afterwards, the mixture is heated and stirred in an oil bath. When the temperature reaches approximately 100 degrees Celsius, the NH bonds in the material break, and iron replaces hydrogen to form N-Fe bonds. This promotes the incorporation of iron into the zirconium-based metal-organic framework material without altering its basic structure.

[0053] This invention also provides an application of an iron-zirconium bimetallic organic framework composite material in the photocatalytic CO2 cycloaddition reaction, the method of which is as follows:

[0054] (1) Before the CO2 cycloaddition reaction, the iron-zirconium bimetallic organic framework composite material was activated in a vacuum environment at 140-160℃.

[0055] (2) The activated iron-zirconium bimetallic organic framework composite material (the amount added can be 15-30 mg) is added to a reactor containing epichlorohydrin (the amount can be 0.767 mL) and tetrabutylammonium bromide as a co-catalyst (the amount added can be 100-300 mg). CO2 is introduced and a xenon lamp is used as the light source (simulating natural sunlight) to carry out the CO2 cycloaddition reaction (the actual current, pressure, etc. during the reaction can be determined according to the actual situation). After the reaction, the yield of cyclic carbonate reaches more than 88%.

[0056] The preparation method of the iron-zirconium bimetallic organic framework composite material of the present invention is further described below with reference to specific embodiments. The dosage error of the materials prepared in the following embodiments and comparative examples is controlled within one-thousandth, and the final yield of cyclic carbonate is the average value of multiple experiments.

[0057] Example 1

[0058] A method for preparing an iron-zirconium bimetallic organic framework composite material, the specific steps of which are as follows:

[0059] (1) Dissolve 50 mg zirconium tetrachloride, 20 mg 1-tetra(4-carboxyphenyl)porphyrin and 1.2 g benzoic acid in 8 mL N,N-dimethylformamide and stir at room temperature for 30 min until completely dissolved. Transfer to a stainless steel high-pressure reactor lined with polytetrafluoroethylene and heat in an oven at 120 °C for 12 h.

[0060] (2) After the hydrothermal reaction product is naturally cooled to room temperature, the obtained material is washed with N,N-dimethylformamide and methanol to obtain the target product. Specifically, N,N-dimethylformamide is stirred for more than 30 minutes, centrifuged and washed, and then fresh N,N-dimethylformamide is added and centrifuged and washed once in the same manner. Subsequently, the product is transferred and centrifuged and washed with methanol for 1-2 hours, and then stirred with fresh methanol for more than 12 hours. The material obtained by centrifugation and washing is placed in a vacuum oven at 60-70°C to dry, thereby obtaining zirconium-based metal-organic framework material.

[0061] (3) Dissolve 50 mg of zirconium-based metal-organic framework material and 50 mg of ferric nitrate nonahydrate in 3 mL of N,N-dimethylformamide (i.e., the total mass ratio of zirconium-based metal-organic framework material and ferric nitrate nonahydrate to the total volume ratio of N,N-dimethylformamide is 100 mg: 6 mL), and transfer them together into a round-bottom flask. Purge nitrogen gas into the solution to cause bubbling for 30 minutes, and heat and reflux in a 100°C oil bath for 5 hours. After natural cooling to room temperature, wash the obtained material according to step (2) above to obtain the iron-zirconium bimetallic organic framework composite material.

[0062] Combination Figure 2 The XRD patterns of the zirconium-based metal-organic framework material prepared in step (2) and the iron-zirconium bimetallic organic framework composite material prepared in step (3) preliminarily indicate that the metallic iron element has been successfully incorporated into the material. The XRD patterns of the zirconium-based metal-organic framework material prepared in step (2) are consistent with those of zirconium elements found in other fields, which can be judged as the successful synthesis of the substance. The XRD pattern of the iron-zirconium bimetallic organic framework composite material prepared in step (3) is consistent with the peak time of the zirconium-based metal-organic framework material prepared in step (2), indicating that the original structure has not changed. The smaller peak height and area indicate that the intermolecular spacing has decreased, and there is metal insertion.

[0063] Application of iron-zirconium bimetallic organic framework composite material in photocatalytic CO2 cycloaddition reaction: In a reactor containing 0.767 mL of epichlorohydrin and 161 mg of tetrabutylammonium bromide (co-catalyst), 20 mg of the above-mentioned iron-zirconium bimetallic organic framework composite material (catalyst) was added, CO2 was introduced, a xenon lamp was used as the light source, the actual current was 18 A, 0.1 MPa, the mixture was stirred, and the reaction was carried out for 5 h. The yield of cyclic carbonate was detected and calculated by GC-MS and was approximately 99.72%.

[0064] Example 2

[0065] (1) Same as in Example 1, except that the amount of iron-zirconium bimetallic organic framework composite material (catalyst) added was changed to 15 mg, and other conditions remained unchanged. The yield of cyclic carbonate was about 93.70%.

[0066] (2) Same as in Example 1, except that the dosage of the iron-zirconium bimetallic organic framework composite material (catalyst) was changed to 25 mg, and other conditions remained unchanged, the yield of cyclic carbonate was about 97.88%.

[0067] (3) Same as in Example 1, except that the dosage of the iron-zirconium bimetallic organic framework composite material (catalyst) was changed to 30 mg, and other conditions remained unchanged. The yield of cyclic carbonate was about 95.08%.

[0068] Example 3

[0069] (1) As in Example 1, when the iron-zirconium bimetallic organic framework composite material (catalyst) was recycled for the second time, the cyclic carbonate yield was about 98.97% under the same conditions.

[0070] (2) As in Example 1, when the iron-zirconium bimetallic organic framework composite material (catalyst) was recycled for the third time, the cyclic carbonate yield was approximately 95.65% under the same conditions.

[0071] (3) As in Example 1, when the iron-zirconium bimetallic organic framework composite material (catalyst) was recycled for the fourth time, the cyclic carbonate yield was approximately 92.17% under the same conditions.

[0072] (4) As in Example 1, when the iron-zirconium bimetallic organic framework composite material (catalyst) was recycled for the 5th time, the cyclic carbonate yield was about 88.50% under the same conditions.

[0073] Example 4

[0074] Same as in Example 1, in step (1), the masses of zirconium tetrachloride, methyl-tetra(4-carboxyphenyl)porphyrin, and benzoic acid are 48 mg, 20 mg, and 1.16 g, respectively, and the amount of N,N-dimethylformamide is 8 mL. Under the same conditions, the yield of cyclic carbonate is about 95.92%.

[0075] Example 5

[0076] Same as in Example 1, in step (1), the masses of zirconium tetrachloride, methyl-tetra(4-carboxyphenyl)porphyrin, and benzoic acid are 52 mg, 21 mg, and 1.24 g, respectively, and the amount of N,N-dimethylformamide is 8 mL. Under the same conditions, the yield of cyclic carbonate is about 92.71%.

[0077] Example 6

[0078] Same as in Example 1, in step (3), the mass of zirconium-based metal-organic framework material and ferric nitrate nonahydrate is 48 mg and 52 mg respectively, and the total amount of N,N-dimethylformamide is 6 mL. Under the same conditions, the yield of cyclic carbonate is about 89.90%.

[0079] Example 7

[0080] Same as in Example 1, in step (3), the mass of zirconium-based metal-organic framework material and ferric nitrate nonahydrate is 52 mg and 48 mg respectively, and the total amount of N,N-dimethylformamide is 6 mL. Under the same conditions, the yield of cyclic carbonate is about 90.28%.

[0081] Comparative Example 1

[0082] Similar to Example 1, using the zirconium-based metal-organic framework material from step (2) of the above invention as a catalyst, with other conditions unchanged, the yield of cyclic carbonate is approximately 54.89%.

[0083] Comparative Example 2

[0084] (1) Same as in Example 1, except that the dosage of tetrabutylammonium bromide (co-catalyst) was changed to 96.7 mg and 0.3 mmol, and other conditions remained unchanged. The yield of cyclic carbonate was about 57.92%.

[0085] (2) Same as in Example 1, except that the dosage of tetrabutylammonium bromide (co-catalyst) was changed to 322 mg and 1.0 mmol, and other conditions remained unchanged. The yield of cyclic carbonate was about 78.65%.

[0086] Comparative Example 3

[0087] Same as in Example 1, except that the dosage of the final product, the iron-zirconium bimetallic organic framework composite material (catalyst), was changed to 10 mg, and other conditions remained unchanged, the yield of cyclic carbonate was approximately 86.85%.

[0088] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any variations or modifications to the above embodiments that are within the spirit and essence of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A bimetallic organic framework composite material of iron and zirconium, characterized in that, Its raw materials include zirconium tetrachloride, meso-tetra(4-carboxyphenyl)porphyrin, benzoic acid, and iron salts; The zirconium tetrachloride, methyl-tetra(4-carboxyphenyl)porphyrin, and benzoic acid are reacted hydrothermally in an organic solvent to obtain a zirconium-based metal-organic framework material, wherein the mass ratio of zirconium tetrachloride, methyl-tetra(4-carboxyphenyl)porphyrin, and benzoic acid is 2.4-2.6:1:58-62. The zirconium-based metal-organic framework material is reacted with the iron salt in an organic solvent to obtain an iron-zirconium bimetallic organic framework composite material; the mass ratio of the zirconium-based metal-organic framework material to the iron salt is 0.9 to 1.1:

1.

2. The iron-zirconium bimetallic organic framework composite material according to claim 1, characterized in that: The iron salt used is ferric nitrate nonahydrate.

3. The iron-zirconium bimetallic organic framework composite material according to claim 1, characterized in that: The organic solvent used is N,N-dimethylformamide.

4. A method for preparing an iron-zirconium bimetallic organic framework composite material, characterized in that, Includes the following steps: S1, zirconium tetrachloride, methyl-4-tetra(4-carboxyphenyl)porphyrin and benzoic acid are dissolved in N,N-dimethylformamide and stirred at room temperature until completely dissolved. The solution is then transferred to a stainless steel high-pressure reactor and subjected to hydrothermal reaction in an oven. S2, after the hydrothermal reaction products have cooled naturally, they are washed and dried to obtain zirconium-based metal-organic framework materials; S3, the zirconium-based metal-organic framework material and ferric nitrate nonahydrate are dissolved in N,N-dimethylformamide, then transferred to a round-bottom flask, nitrogen gas is introduced to bubble the solution, then heated and stirred in an oil bath, and the reaction product is washed after natural cooling to obtain the iron-zirconium bimetallic organic framework composite material.

5. The method for preparing the iron-zirconium bimetallic organic framework composite material according to claim 4, characterized in that, In step S1: The mass ratio of zirconium tetrachloride, methyl-tetra(4-carboxyphenyl)porphyrin, and benzoic acid is 2.4–2.6:1:58–62. The total mass ratio of zirconium tetrachloride, methyl-tetra(4-carboxyphenyl)porphyrin, and benzoic acid to the volume ratio of N,N-dimethylformamide is 1.2–1.32 g: 8 mL.

6. The method for preparing the iron-zirconium bimetallic organic framework composite material according to claim 4, characterized in that, In step S1: The stirring and dissolving time is 30 ± 5 min; The stainless steel high-pressure reactor is lined with polytetrafluoroethylene. During the hydrothermal reaction process, the oven temperature is 120±10℃, and the hydrothermal reaction time is more than 12 hours.

7. The method for preparing the iron-zirconium bimetallic organic framework composite material according to claim 4, characterized in that, In step S2: During the washing process, the hydrothermal reaction products are centrifuged and washed with N,N-dimethylformamide and methanol, respectively. The drying process is carried out in a vacuum oven at a temperature of 60–70°C.

8. The method for preparing the iron-zirconium bimetallic organic framework composite material according to claim 4, characterized in that, In step S3: The mass ratio of the zirconium-based metal-organic framework material to the ferric nitrate nonahydrate is 0.9–1.1:1; The total mass ratio of the zirconium-based metal-organic framework material and the ferric nitrate nonahydrate to the total volume ratio of the N,N-dimethylformamide is 96-104:6 ml.

9. The method for preparing the iron-zirconium bimetallic organic framework composite material according to claim 4, characterized in that, In step S3: The bubble treatment time is 30 minutes or more; The temperature of the oil bath is 100-120℃, and the heating and stirring time is more than 5 hours.

10. The application of the iron-zirconium bimetallic organic framework composite material as described in claims 1 to 3 in the photocatalytic CO2 cycloaddition reaction.

11. The application according to claim 10, characterized in that, The iron-zirconium bimetallic organic framework composite material was activated in a vacuum environment; The activated iron-zirconium bimetallic organic framework composite material was added to a reactor containing epichlorohydrin and tetrabutylammonium bromide, CO2 was introduced, and a xenon lamp was used as the light source to carry out a CO2 cycloaddition reaction.

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