Flaky bismuth-based metal organic framework material and preparation method thereof

Abstract

The invention discloses a flaky bismuth-based metal organic framework material and a preparation method thereof, and the preparation method comprises the following steps: mixing a bismuth salt and a polyacid organic ligand, then mixing with a grinding ball, and carrying out ball milling treatment to obtain the bismuth-based metal organic framework material. The bismuth-based metal organic framework material with a sheet-shaped morphology structure is prepared by adopting a mechanical ball milling method, reactants are crushed in a ball mill by utilizing mechanical energy, rapid reaction of bismuth metal ions and organic ligands is promoted, no solvent is needed in the whole reaction process, or only a trace amount of solvent is needed, and the use of a large amount of organic solvent is avoided. The reaction can be directly promoted by mechanical force at room temperature, the reaction time is short, the yield is high, the energy consumption is low, and the method is green and environment-friendly. The bismuth-based metal organic framework material has the characteristics of unique flaky morphology structure, high specific surface area, high structural stability and the like, is adjustable in size, and can be widely applied to the fields of carbon dioxide adsorption reduction, adsorption of pollutants in water bodies and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of organic-inorganic hybrid materials, and in particular to a flaky bismuth-based metal organic framework material and a preparation method thereof. Background Art

[0002] There are many reports on the preparation methods of bismuth-based metal organic framework materials. For example, Chinese patent CN117209791A discloses the preparation of bismuth-containing metal organic framework porous nanomaterials by solvent thermal method. The material is based on the central metal Bi 3+ As the connecting node, organic ligands are used as bridges to connect with Bi 3+ A one-dimensional, two-dimensional or three-dimensional network porous topological structure is formed by chelating and coordinating connections. However, the existing preparation methods are mostly based on hydrothermal and solvent thermal methods, which require high temperatures and a large amount of solvents, have high energy consumption, and are not environmentally friendly. In recent years, a variety of green synthesis methods have been developed, such as microwave reaction method, ultrasonic method, etc. For example, Chinese patent CN116333333A discloses a method for preparing bismuth-based metal organic framework materials using microwave reaction method, and the bismuth-based metal organic framework materials obtained by this method are regular hexagonal prisms with uniform crystal size. Chinese patent CN113773348A discloses a method for preparing bismuth-based metal organic framework materials in a water system using a secondary ultrasonic growth method, and the bismuth-based metal organic framework materials have an elongated strip morphology and a bottom diameter of nanometer level. Chinese patent CN113773348A discloses a method for preparing bismuth-based metal organic framework materials using ultrasonic reaction method, and its yield is at the level of several hundred milligrams, and ultrasonic treatment is required for 5 hours. However, these synthesis methods still have many drawbacks. For example, microwave reaction methods suffer from high equipment costs and strict requirements on reaction vessel materials; ultrasonic reaction methods suffer from issues with ultrasonic field uniformity, low energy transfer efficiency, and difficulty in scaling up the reaction. Furthermore, most synthesis methods require the use of organic solvents as reaction systems, which can generate toxic and hazardous waste and pose certain risks, limiting their large-scale production and practical application.

[0003] In this context, mechanical ball milling, as an emerging mechanochemical synthesis technology, has become a research hotspot in the field of MOF preparation due to its high efficiency, greenness and low cost.

[0004] While mechanical ball milling has been reported for preparing metal framework materials, for example, Chinese patent CN118047955A discloses a mechanochemical method for preparing high-surface-area metal-organic frameworks. Using a two-step ball milling method assisted by trace amounts of organic solvents, waste polyethylene terephthalate (PET) is degraded into terephthalate and ethylene glycol via mechanochemical action in a strong alkaline environment. The terephthalate then coordinates with metal ions under mechanochemical action assisted by trace amounts of organic solvents to prepare high-surface-area MOFs. Chinese patent CN119463206 A discloses a method for preparing a UTSA-16 structure metal-organic framework, comprising the following steps: adding a metal salt and potassium citrate to an auxiliary solvent in sequence, then adding an alkaline solution, adjusting the pH value to 8-13, and treating the mixture by ball milling to obtain a reaction solution; centrifuging the reaction solution, collecting the solid portion, washing it with ether, soaking it in methanol, and drying it to obtain a precursor; activating the precursor at 80-90°C to remove the solvent in the pores to obtain a UTSA-16 structure metal-organic framework.

[0005] However, there has been no report on the preparation of bismuth-based metal-organic framework materials with specific morphology, namely flake-like bismuth, by mechanical ball milling. Summary of the Invention

[0006] Based on this, the present invention aims to provide a sheet-like bismuth-based metal-organic framework material and a preparation method thereof. The preparation method has the characteristics of low preparation cost, simple process, safe and environmentally friendly process, high yield, and low energy consumption.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A first aspect of the present invention provides a method for preparing a sheet-like bismuth-based metal-organic framework material, comprising the following steps:

[0009] S1. mixing a bismuth salt and a polyacid organic ligand to obtain a mixture;

[0010] S2. The obtained mixture is mixed with grinding balls and subjected to ball milling treatment to obtain a flaky bismuth-based metal-organic framework material.

[0011] Preferably, in order to reduce energy loss, increase product yield, and shorten the preparation cycle, a small amount of auxiliary solvent can be added during the grinding process to accelerate the reaction of the grinding process.

[0012] Preferably, the grinding balls used for ball milling are zirconia balls;

[0013] Preferably, to ensure the formation of bismuth-based metal organic framework materials, the mass ratio of the bismuth salt to the polyacid organic ligand is 1:1-10;

[0014] Further preferably, in order to improve the product yield, the mass ratio of the bismuth salt to the polyacid organic ligand is 1:1-5.

[0015] Preferably, the ball milling temperature is room temperature, the ball milling speed is 500-5000 rpm / min, and the ball milling time is 0.5 min to 10 min.

[0016] Preferably, the bismuth salt is one of bismuth nitrate pentahydrate, bismuth acetate, and bismuth oxynitrate, or a combination of two or more thereof.

[0017] Preferably, the polyacid organic ligand is one or a combination of two or more of 1,3,5-pyromellitic acid, triazine-2,4,6-triyl-tribenzoic acid, and biphenyl-3,3',5,5'-tetracarboxylic acid. 1,3,5-pyromellitic acid reacts with bismuth salts to form CAU-7 and CAU-17; triazine-2,4,6-triyl-tribenzoic acid reacts with bismuth salts to form CAU-35; and biphenyl-3,3',5,5'-tetracarboxylic acid reacts with bismuth salts to form NOTT-220. CAU-7, CAU-17, CAU-35, and NOTT-220 are all bismuth-based metal-organic frameworks with different topological structures.

[0018] Preferably, the ball milling auxiliary solvent is one of methanol, ethanol, DMF, 1,2-propylene glycol, or a combination of two or more thereof.

[0019] The second aspect of the present invention provides a flaky bismuth-based metal-organic framework material obtained by the above preparation method.

[0020] The third aspect of the present invention provides the use of the above-mentioned sheet-like bismuth-based metal organic framework material in the adsorption and reduction of carbon dioxide and the adsorption of pollutants in water bodies.

[0021] The present invention has the following beneficial effects:

[0022] (1) The present invention uses a mechanical ball milling method to prepare a bismuth-based metal-organic framework material with a flaky structure. By utilizing mechanical energy to crush the reactants in the ball mill, the reaction between the bismuth metal ions and the organic ligand is rapidly promoted. The entire reaction process does not require a solvent, or only requires a trace amount of auxiliary solvent, thereby avoiding the use of a large amount of organic solvent. Compared with the traditional solvothermal method, the preparation method of the present invention can directly promote the reaction through mechanical force at room temperature, and has a short reaction time, high yield, low energy consumption, and is environmentally friendly.

[0023] (2) The ball milling equipment used in the preparation method of the present invention has a simple structure, and its parameters (such as ball milling time, rotation speed, and the material and size of the balls and kettle) are easily controlled, thereby adjusting the particle size, morphology, specific surface area, and other characteristics of the desired product. This controllability makes the ball milling method highly flexible and adaptable in the synthesis of bismuth-based metal-organic frameworks. Furthermore, the addition of a trace amount of auxiliary solvent during the ball milling process can accelerate the reaction and increase the product yield.

[0024] (3) The bismuth-based metal-organic framework material prepared by the present invention has the characteristics of unique flaky morphology, high specific surface area and high structural stability, and its size is controllable. It can be widely used in the fields of carbon dioxide adsorption reduction (the selectivity of the product formic acid is greater than 90%, and the by-product is gaseous hydrogen), adsorption of pollutants in water (such as rhodamine), etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is an SEM image of the bismuth-based metal-organic framework material prepared in Example 1;

[0026] Figure 2 This is the XRD pattern of the bismuth-based metal-organic framework material prepared in Example 1;

[0027] Figure 3 The stability test of the bismuth-based metal organic framework material prepared in Example 1 at different pH values was performed;

[0028] Figure 4 This is an SEM image of the bismuth-based metal-organic framework material prepared in Example 2;

[0029] Figure 5 The XRD patterns of the samples obtained in Comparative Example 1 and Comparative Example 2 are shown in FIG.

[0030] Figure 6 This is the adsorption diagram of RhB on the bismuth-based metal-organic framework material prepared in Example 1;

[0031] Figure 7 The electrochemical carbon dioxide reduction performance of the bismuth-based metal organic framework material prepared in Example 1. DETAILED DESCRIPTION

[0032] To facilitate understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0033] Example 1

[0034] Mix 30 mg of bismuth nitrate pentahydrate and 150 mg of 1,3,5-trimethylbenzene trimesic acid and stir them evenly to obtain a mixture; add 100 μl of ethanol to the mixture and mix it evenly, and place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill reaction is carried out at a speed of 4000 rpm / min for 1 minute; the final product is transferred to a large beaker, methanol is added, and after centrifugation and washing three times, a bismuth-based metal-organic framework material is obtained. After testing, the obtained bismuth-based metal-organic framework material is in the form of flakes with a length of 800 nm-1.5 μm, and the size distribution is uniform, with a specific surface area of 425 m 2 / g, with a yield of 95%.

[0035] Example 2

[0036] Mix 30g of bismuth nitrate pentahydrate and 150g of 1,3,5-benzenetricarboxylic acid and stir them evenly to obtain a mixture; add 5ml of ethanol to the mixture and mix it evenly, and place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill is reacted at a speed of 4000rpm / min for 3min; the final product is transferred to a large beaker, methanol is added, and after centrifugation and washing three times, a bismuth-based metal-organic framework material is obtained. After testing, the obtained bismuth-based metal-organic framework material is in the form of flakes with a length of 800nm-1.5μm, and the size distribution is uniform, with a specific surface area of 387m 2 / g, with a yield of 90%.

[0037] Example 3

[0038] Mix 30 mg of bismuth nitrate pentahydrate and 30 mg of biphenyl-3,3ˊ,5,5ˊ-tetracarboxylic acid and stir them evenly to obtain a mixture; add 100 μl of methanol to the mixture and mix it evenly, and place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill reaction is carried out at a speed of 3000 rpm / min for 1 minute; the final product is transferred to a large beaker, methanol is added, and after centrifugation and washing three times, a bismuth-based metal organic framework material is obtained. After testing, the obtained bismuth-based metal organic framework material is in the form of flakes with a length of 800 nm-1.5 μm, and the size distribution is uniform, with a specific surface area of 395 m 2 / g, with a yield of 85%.

[0039] Example 4

[0040] Mix 30 mg of bismuth nitrate pentahydrate and 150 mg of 1,3,5-trimethylbenzene trimesic acid and stir them evenly to obtain a mixture; add 100 μl of DMF to the mixture and mix it evenly, and place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill reaction is carried out at a speed of 4000 rpm / min for 1 minute; the final product is transferred to a large beaker, methanol is added, and after centrifugation and washing three times, a bismuth-based metal-organic framework material is obtained. After testing, the obtained bismuth-based metal-organic framework material is in the form of flakes with a length of 800 nm-1.5 μm, and the size distribution is uniform, with a specific surface area of 418 m 2 / g, with a yield of 95%.

[0041] Example 5

[0042] Mix 30 mg of bismuth nitrate pentahydrate and 150 mg of 1,3,5-trimethylbenzene trimesic acid and stir them evenly to obtain a mixture; add 100 μl of DMF to the mixture and mix it evenly, and place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill is reacted at a speed of 3000 rpm / min for 3 minutes; the final product is transferred to a large beaker, methanol is added, and after centrifugation and washing three times, a bismuth-based metal-organic framework material is obtained. The obtained bismuth-based metal-organic framework material is tested to be in the form of flakes with a length of 1.8 μm-3.2 μm, and a uniform size distribution, with a specific surface area of 367 m 2 / g, with a yield of 85%.

[0043] Example 6

[0044] Mix 30 mg of bismuth nitrate pentahydrate and 150 mg of biphenyl-3,3ˊ,5,5ˊ-tetracarboxylic acid and stir them evenly to obtain a mixture; add 100 μl of DMF to the mixture and mix it evenly, and place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill reaction is carried out at a speed of 3000 rpm / min for 3 minutes; the final product is transferred to a large beaker, methanol is added, and after centrifugation and washing three times, a bismuth-based metal-organic framework material is obtained. The obtained bismuth-based metal-organic framework material is tested to be in the form of flakes with a length of 1.5μm-3.0μm, and a uniform size distribution, with a specific surface area of 380m 2 / g, with a yield of 90%.

[0045] Example 7

[0046] Mix 30 mg of bismuth nitrate pentahydrate and 150 mg of 1,3,5-trimethylbenzene trimesic acid and stir them evenly to obtain a mixture; add 100 μl of DMF to the mixture and mix it evenly, and place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill is reacted at a speed of 2000 rpm / min for 3 minutes; the final product is transferred to a large beaker, methanol is added, and after centrifugation and washing three times, a bismuth-based metal-organic framework material is obtained. The obtained bismuth-based metal-organic framework material was tested to be in the form of flakes with a length of 3.5 μm-5.0 μm, and a uniform size distribution, with a specific surface area of 344 m 2 / g, with a yield of 80%.

[0047] Example 8

[0048] Mix 30 mg of bismuth nitrate pentahydrate and 300 mg of 1,3,5-benzenetricarboxylic acid and stir them evenly to obtain a mixture; add 100 μl of DMF to the mixture and mix it evenly, and place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill is reacted at a speed of 2000 rpm / min for 5 minutes; the final product is transferred to a large beaker, methanol is added, and after centrifugation and washing three times, a bismuth-based metal-organic framework material is obtained. The obtained bismuth-based metal-organic framework material was tested to be in the form of flakes with a length of 3.3 μm-4.5 μm, and a uniform size distribution, with a specific surface area of 358 m 2 / g, with a yield of 83%.

[0049] Example 9

[0050] Mix 30 mg of bismuth nitrate pentahydrate and 150 mg of 1,3,5-trimethylbenzene trimesic acid and stir them evenly to obtain a mixture; add 100 μl of 1,2-propylene glycol to the mixture and mix it evenly, and place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill is reacted at a speed of 1000 rpm / min for 5 minutes; the final product is transferred to a large beaker, methanol is added, and after centrifugation and washing three times, a bismuth-based metal-organic framework material is obtained. After testing, the obtained bismuth-based metal-organic framework material is in the form of flakes with a length of 5.1 μm-6.8 μm, and the size distribution is uniform, with a specific surface area of 330 m 2 / g, with a yield of 80%.

[0051] Example 10

[0052] Mix 30 mg of bismuth oxynitrate and 150 mg of 1,3,5-trimethylbenzene trimesic acid and stir them evenly to obtain a mixture; add 100 μl of ethanol to the mixture and mix it evenly, and place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill is reacted at a speed of 1000 rpm / min for 5 minutes; the final product is transferred to a large beaker, methanol is added, and after centrifugation and washing three times, a bismuth-based metal organic framework material is obtained. After testing, the obtained bismuth-based metal organic framework material is in the form of flakes with a length of 4.8 μm-5.8 μm, and the size distribution is uniform, with a specific surface area of 361 m 2 / g, with a yield of 85%.

[0053] Example 11

[0054] Mix 30 mg of bismuth acetate and 150 mg of triazine-2,4,6-triyl-tribenzoic acid and stir them evenly to obtain a mixture; add 100 μl of methanol to the mixture and mix it evenly; place the container containing the mixture sample in a ball mill, add zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, and mill the reaction at a speed of 500 rpm / min for 10 minutes; transfer the final product to a large beaker, add methanol, and centrifuge and wash three times to obtain a bismuth-based metal-organic framework material. The obtained bismuth-based metal-organic framework material was tested to be in the form of flakes with a length of 7.5-9.5 μm and a uniform size distribution, with a specific surface area of 332 m 2 / g, with a yield of 85%.

[0055] Example 12

[0056] Mix 30 mg of bismuth nitrate pentahydrate and 150 mg of triazine-2,4,6-triyl-tribenzoic acid and stir them evenly to obtain a mixture; add 80 μl of methanol to the mixture and mix it evenly. Place the container containing the mixture sample in a ball mill, add zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, and mill the reaction at a speed of 5000 rpm / min for 30 seconds; transfer the final product to a large beaker, add methanol, and centrifuge and wash three times to obtain a bismuth-based metal-organic framework material. The obtained bismuth-based metal-organic framework material was tested to be in the form of flakes with a length of 800 nm-1.5 μm and a uniform size distribution. The specific surface area was 412 m 2 / g, with a yield of 95%.

[0057] Comparative Example 1

[0058] Mix 30 mg of bismuth nitrate pentahydrate and 150 mg of 1,3,5-trimethylbenzene trimesic acid and stir them evenly to obtain a mixture; add 100 μl of ethanol to the mixture and mix it evenly, and place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill is rotated at a speed of 400 rpm / min for 5 minutes; the final product is transferred to a large beaker, methanol is added, and the sample is obtained after centrifugation and washing three times. XRD test shows that the obtained product (sample) is a non-bismuth-based metal organic framework material, see Figure 5 .

[0059] Comparative Example 2

[0060] Mix 30 mg of bismuth nitrate pentahydrate and 150 mg of 1,3,5-trimethylbenzene trimesic acid and stir them evenly to obtain a mixture; add 100 μl of ethanol to the mixture and mix it evenly, and place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill is rotated at a speed of 200 rpm / min for 10 minutes; the final product is transferred to a large beaker, methanol is added, and the sample is obtained after centrifugation and washing three times. XRD test shows that the obtained product (sample) is a non-bismuth-based metal organic framework material, see Figure 5 .

[0061] Comparative Example 3

[0062] Mix 30 mg of bismuth nitrate pentahydrate and 150 mg of 1,3,5-trimethylbenzene trimesic acid and stir them evenly to obtain a mixture; place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill reaction is carried out at a speed of 1000 rpm / min for 5 minutes; the final product is transferred to a large beaker, methanol is added, and centrifugation and washing are performed three times to obtain a bismuth-based metal-organic framework material. The obtained bismuth-based metal-organic framework material was tested to be in the form of flakes with a length of 1.3μm-2.8μm, a uniform size distribution, and a specific surface area of 381m 2 / g, with a yield of 60%.

[0063] Comparative Example 4

[0064] Mix 30 mg of bismuth nitrate pentahydrate and 150 mg of triazine-2,4,6-triyl-tribenzoic acid and stir evenly to obtain a mixture; place the container containing the mixture sample in a ball mill. After adding zirconium oxide grinding balls into the ball mill at a ball-to-material ratio of 10:1, the ball mill reaction is carried out at a speed of 3500 rpm / min for 1 minute; the final product is transferred to a large beaker, methanol is added, and centrifugation and washing are performed three times to obtain a bismuth-based metal organic framework material. The obtained bismuth-based metal organic framework material was tested to be in the form of flakes with a length of 1.0 μm-2.3 μm, a uniform size distribution, and a specific surface area of 393 m2 / g, with a yield of 67%.

[0065] The bismuth-based metal organic framework materials prepared in Examples 1 and 2 were characterized, and the results are shown in Figure 1-3 .

[0066] from Figure 1 It can be seen that the bismuth-based metal organic framework material prepared in Example 1 is in the form of flakes with a length of 800nm-1.5μm and a uniform size distribution, and a specific surface area of 425m 2 / g.

[0067] from Figure 2 It can be seen that the bismuth-based metal-organic framework material prepared in Example 1 has good crystallization performance, and shows a layered diffraction peak unique to the bismuth-based metal-organic framework material in the diffraction angle of 5°-50°, and the positions of all diffraction peaks of the bismuth-based metal-organic framework material correspond one-to-one with the positions of the diffraction peaks of the known CAU-17 crystal structure, indicating that the bismuth-based metal-organic framework material and CAU-17 have the same crystal structure, that is, the obtained bismuth-based metal-organic framework material is CAU-17.

[0068] from Figure 3 It can be seen that the sheet-like bismuth-based metal-organic framework material has high stability in the pH range of 2-13.

[0069] from Figure 4 It can be seen that the bismuth-based metal organic framework material prepared in Example 2 is in the form of flakes with a length of 800 nm to 1.5 μm and a uniform size distribution. The specific surface area is 387 m 2 / g.

[0070] from Figure 5 It can be seen that the products obtained in Comparative Examples 1 and 2 are non-bismuth-based metal-organic framework materials. The reason for this result is that during the ball milling process, the conversion of mechanical energy into chemical energy or other forms of energy requires a certain amount of time to accumulate. The low rotation speed slows the rate of energy transfer and accumulation, which cannot meet the energy conditions (especially temperature) required for sample preparation, thus affecting product formation.

[0071] Test Example 1

[0072] The flaky bismuth-based organic framework material prepared in Example 1 was used as an adsorbent for the adsorption of dyes.

[0073] Specific steps: 1) Dissolve 10 mg of the bismuth-based metal-organic framework material prepared in Example 1 in 20 ml of a 100 mg / L rhodamine B (RhB) solution. The suspension is magnetically stirred. Every 15 minutes, about 1 mL of the suspension is extracted with a syringe and passed through a 0.22 μm polytetrafluoroethylene syringe filter to completely remove the adsorbed powder. The residual concentration of RhB is analyzed by UV-visible spectroscopy (the characteristic absorption peak of RhB at 554 nm) to obtain the adsorption curve of RhB. The results are shown in Figure 2. Figure 6 .

[0074] Depend on Figure 6 It can be seen that the flake bismuth-based organic framework material can reduce the RhB concentration from 100 ml / L to 5 mg / L, with a removal rate greater than 95%.

[0075] These results demonstrate that the flaky bismuth-based metal-organic framework (MOF) prepared in this study exhibits a distinct microscopic morphology compared to the rod-shaped CAU-17. The resulting flaky bismuth-based MOF exhibits excellent adsorption performance for RhB, making it a promising candidate for a highly efficient dye adsorbent.

[0076] At the same time, the electrochemical carbon dioxide reduction test was carried out on the bismuth-based metal organic framework material prepared in Example 1, and the product obtained was mainly formic acid. The specific results are shown in Figure 7 .

[0077] Depend on Figure 7 The results show that under the condition of -0.9V vs RHE, the selectivity of formic acid in the electrocatalytic reduction products of carbon dioxide by the sheet-like bismuth-based metal-organic framework material is greater than 90%, showing high performance.

[0078] The present invention is not limited to the above-mentioned specific implementation methods. Various changes made by ordinary technicians in this field based on the above-mentioned concept without creative work are all within the scope of protection of the present invention.

Claims

1. A method for preparing a flaky bismuth-based metal-organic framework material, characterized in that: The following steps are involved: S1. mixing a bismuth salt and a polyacid organic ligand to obtain a mixture; S2. The obtained mixture is mixed with the grinding agent, and ball milling is performed to obtain a bismuth-based metal organic framework material.

2. The method for preparing a flaky bismuth-based metal-organic framework material according to claim 1, characterized in that: During the ball milling process, a ball milling auxiliary solvent is added to accelerate the reaction.

3. The method for preparing a flaky bismuth-based metal-organic framework material according to claim 1, characterized in that: The grinding balls used for ball milling are zirconium oxide balls; the ratio of the total mass of the bismuth salt and the polyacid organic ligand to the total mass of the grinding balls is 1:10-20.

4. The method for preparing a flaky bismuth-based metal-organic framework material according to claim 2, wherein: The ball milling temperature is room temperature, the ball milling speed is 500-5000 rpm / min, and the ball milling time is 0.5 min-10 min.

5. The method for preparing a flaky bismuth-based metal-organic framework material according to any one of claims 1 to 3, characterized in that: The mass ratio of the bismuth salt to the polyacid organic ligand is 1:1-10.

6. The method for preparing a flaky bismuth-based metal-organic framework material according to claim 1, characterized in that: The bismuth salt is one of bismuth nitrate pentahydrate, bismuth acetate, and bismuth oxynitrate, or a combination of two or more thereof.

7. The method for preparing a flaky bismuth-based metal-organic framework material according to claim 1, characterized in that: The polyacid organic ligand is one or a combination of two or more of 1,3,5-trimellitic acid, triazine-2,4,6-triyl-tribenzoic acid, and biphenyl-3,3',5,5'-tetracarboxylic acid.

8. The sheet-like bismuth-based metal-organic framework material according to claim 2, characterized in that: The ball milling auxiliary solvent is one of methanol, ethanol, DMF, and 1,2-propylene glycol, or a combination of two or more thereof.

9. A sheet-like bismuth-based metal-organic framework material obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the flaky bismuth-based metal organic framework material according to claim 9 in carbon dioxide adsorption and reduction and adsorption of pollutants in water.

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