Preparation method of Co-based MOF material constructed based on H3BTTC

Abstract

The invention relates to a preparation method of a Co-based MOF material constructed based on H3BTTC. The preparation method comprises the following steps: adding a ligand and a metal salt into N, N-dimethylacetamide through a conventional solvothermal synthesis method, adding a tetrafluoroboric acid aqueous solution to adjust the pH value and polarity of the solution, heating and crystallizing in a drying oven, washing a product with a solvent for multiple times, and carrying out vacuum drying to obtain a target material. The method can accurately regulate and control pore channels, conditions are mild and efficient, the performance of the material in the fields of gas adsorption and separation, catalysis, sensing and the like is effectively improved, and the remarkable advantages are enhanced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal-organic framework materials (MOFs), and particularly relates to a preparation method for synthesizing Co-based MOF materials by a space-occupying and guiding strategy and regulating pore structures, which is suitable for gas adsorption and separation, catalysis and sensing fields. BACKGROUND

[0002] As a member of the porous material family, metal-organic framework materials (MOFs) have permanent pores, diverse chemical structures and high specific surface area, and are widely used in the fields of adsorption and separation and catalysis.

[0003] In the past period of time, the synthesis of MOF materials blindly pursues materials with large pore diameters, and existing modification strategies cannot simultaneously consider "high adsorption capacity, high separation selectivity, structural stability and synthesis feasibility", resulting in poor structural stability of some materials and easy formation of interpenetrating structures, and when the pore is divided by introducing auxiliary ligands, adjusting ligand structure or multi-metal cluster coordination, the synthesis difficulty and product uncertainty are significantly increased.

[0004] Benzene [1,2-b:3,4-b':5,6-b'] trithiophene-2,5,8-tricarboxylic acid (H3BTTC) is a sulfur-containing tridentate carboxylic acid ligand with good space adaptability and coordination flexibility, and can also be combined with building blocks formed by different coordination numbers of metal SBUs. This feature is more helpful to build MOFs with diverse pores and novel topological structures and to uniformly expose more active sites, thereby improving the contact efficiency with target molecules and significantly enhancing the adsorption and catalytic and sensing performance of the material. SUMMARY

[0005] The purpose of the present application is to synthesize a new Co-based MOF material

[0006] Another purpose of the present application is to develop a simple synthesis procedure to regulate the pore structure. The feature is that by introducing mononuclear Co(DMA)6 as a space-occupying site, the torsion angle of ligand coordination is changed, thereby causing the pore structure of the MOF material to change, forming a new topological structure, and improving the adsorption and separation and catalytic and sensing effect of the material.

[0007] TECHNICAL SCHEME

[0008] In order to achieve the above purpose, the present application provides the following scheme:

[0009] 1) Weigh 0.005 g of benzo[1,2-b:3,4-b':5,6-b']trithiophene-2,5,8-tricarboxylic acid (H3BTTC) and 0.006 g of CoCl2·6H2O and dissolve them in 1 mL of N,N-dimethylacetamide (DMA), and name it solution A. Take 0.050 mL of methanol solution and name it solution B. Take 0.040 mL of tetrafluoroboric acid aqueous solution (50 wt%) and name it solution C. Add solution B to solution A and mix thoroughly by sonication. Then add solution C to obtain a mixed solution for later use.

[0010] 2) Pour the above mixture into a 20 ml screw-top glass bottle with a PTFE / silicone composite gasket, seal it, and place it in a 105°C oven for 48 hours to obtain pinkish-purple crystals. Collect the crystals, wash them with DMA 3-5 times, and dry them in a 60°C oven to obtain the Co-based MOF material.

[0011] 3. The preparation method according to claim 2, wherein the B solution is not necessarily added and can be used to prepare Co-based MOF materials with regular morphology without affecting the synthesis of the material.

[0012] This invention not only provides a novel method for synthesizing Co-based MOF materials, but also utilizes mononuclear Co(DMA)6 for spatial occupancy, altering the torsion angle of ligand coordination and consequently changing the pore structure of the MOF material to form a new topology, thereby improving the material's adsorption, separation, and catalytic effects. The entire preparation process operates under relatively mild reaction conditions, requires minimal equipment, and is easy to implement. Attached Figure Description

[0013] Figure 1 A schematic diagram of the single-crystal structure of a Co-based MOF material;

[0014] Figure 2 PXRD characterization data of Co-based MOF materials and their properties in the low-boiling solvent acetonitrile;

[0015] Figure 3 TGA characterization data for Co-based MOF materials;

[0016] Figure 4 77K nitrogen adsorption curves and pore size distribution of Co-based MOF materials Detailed Implementation

[0017] Example 1. (1) Weigh 0.005 g of benzo[1,2-b:3,4-b':5,6-b']trithiophene-2,5,8-tricarboxylic acid (H3BTTC) and 0.006 g of CoCl2·6H2O and dissolve them in 1 mL of N,N-dimethylacetamide (DMA), and name it Solution A.

[0018] Take 0.050 mL of the methanol solution and name it solution B.

[0019] Take 0.040 mL of tetrafluoroboric acid aqueous solution (50 wt%), name it solution C. Add solution B to solution A, mix thoroughly by sonication, and then add solution C to obtain a mixed solution for later use.

[0020] (2) Pour the above mixture into a 20 ml screw-top glass bottle with a PTFE / silicone composite gasket, seal it, and place it in a 105°C oven for 48 hours to obtain pinkish-purple crystals. Collect the crystals, wash them with DMA 3-5 times, and dry them in a 60°C oven to obtain the Co-based MOF material.

[0021] In Example 1, the trinuclear Co cluster formed by CoCl2 provides open metal sites for the Co-based MOF material to enhance gas adsorption and catalytic capabilities; H3BTTC enhances the structural stability and good coordination flexibility of the Co-based MOF material, and its Lewis base sites can synergistically enhance the adsorption and catalytic performance with the metal sites.

[0022] The structure of the Co-based MOF material prepared in Example 1 is as follows: Figure 1 As shown, from Figure 1 (a) It can be seen that the prepared Co-based MOF has a trinuclear Co cluster structural unit, a mononuclear Co(DMA)6 structural unit, and an H3BTTC structural unit, as well as the corresponding simplified diagram. Figure 1 (b) shows the three different cage-like structures in the structure and their corresponding schematic diagrams. Figure 1 (c) represents the stacking order diagram of the three cage-like structures. Figure 1 (d) is a polyhedral diagram. The above description is only a preferred embodiment of the present invention. It should be noted that in actual applications, the type and amount of raw materials and reaction conditions can be adjusted as needed. For those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a Co-based MOF material, characterized in that, Its preparation method and structural characteristics.

2. The preparation method according to claim 1, characterized in that, The Co-based MOFs were obtained by the following method: 1) Weigh 0.005 g of benzo[1,2-b:3,4-b':5,6-b']trithiophene-2,5,8-tricarboxylic acid (H3BTTC) and 0.006 g of CoCl2·6H2O and dissolve them in 1 mL of N,N-dimethylacetamide (DMA), and name it solution A. Take 0.050 mL of methanol solution and name it solution B. Take 0.040 mL of tetrafluoroboric acid aqueous solution (50 wt%) and name it solution C. Add solution B to solution A and mix thoroughly by sonication. Then add solution C to obtain a mixed solution for later use. 2) Pour the above mixture into a 20 ml screw-top glass bottle with a PTFE / silicone composite gasket, seal it, and place it in a 105°C oven for 48 hours to obtain pinkish-purple crystals. Collect the crystals, wash them with DMA 3-5 times, and dry them in a 60°C oven to obtain the Co-based MOF material.

3. The preparation method according to claim 2, characterized in that, The B solution is not required and can be used to prepare Co-based MOF materials with regular morphology without affecting the synthesis of the material.

4. The structural feature according to claim 1, characterized in that, By changing the channel size through a space-occupying collaborative guidance strategy, the MOF channel structure can be altered using a single-core Co(DMA)6.

5. The structural feature according to claim 4, characterized in that, Such structural features are beneficial to the overall stability of the structure and the adsorption, separation, catalysis, and sensing of specific gases.

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