Functionalized uiO-66 metal framework material, and preparation method and application thereof

Abstract

The application relates to the technical field of metal organic framework materials, and discloses a functionalized UiO-66 metal framework material and a preparation method and application thereof. The functionalized UiO-66 metal framework material comprises the following raw materials: a zirconium source, an organic ligand, a polar aprotic solvent and an adjusting agent; the adjusting agent comprises an organic acid and alcohol. The functionalized UiO-66 metal framework material provided by the application has the advantages of small particle size, large specific surface area, a nano-disordered pore structure, rich crystal defects and good gas adsorption performance. The preparation method of the material is simple, the organic acid and alcohol composite adjusting agent are added, the adjusting agent is used as a second linker to compete with the organic ligand for coordination with zirconium ions, the pore structure, the morphology and size and the defect structure of the functionalized UiO-66 metal framework material are regulated, and by selecting different organic ligands, the UiO-66 metal framework material which is good in adsorption performance and is modified by different functional groups can be obtained.

Description

Technical Field

[0001] This invention relates to the field of metal-organic framework materials technology, and in particular to a functionalized UiO-66 metal framework material, its preparation method, and its application. Background Technology

[0002] UiO-66 metal framework material has advantages such as large specific surface area, adjustable porosity, good structural stability, and high designability, and has broad application prospects in fields such as gas adsorption, separation, storage, catalysis, biomedical devices, and energy.

[0003] Functionalized UiO-66 metal framework materials typically exhibit good gas adsorption properties. For example, NH2-UiO-66 metal framework materials prepared from amino-containing ligands and zirconium ions possess hexagonal channels and two pore structures with diameters of 0.8 nm and 1.1 nm. Compared to UiO-66, NH2-UiO-66 has a larger specific surface area (1000 m² / m³). 2 / g or more) and pore volume (0.5cm) 3 / g); at the same time, the amino group imparts hydrogen bonding sites to NH2-UiO-66, which improves the material's adsorption capacity for gases through strong interactions such as hydrogen bonds. However, existing functionalized UiO-66 metal framework materials have drawbacks such as uneven particle size, large particle size, and few gas adsorption sites. Summary of the Invention

[0004] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, one objective of the present invention is to provide a functionalized UiO-66 metal framework material; a second objective is to provide a method for preparing such a functionalized UiO-66 metal framework material; and a third objective is to provide applications of such a functionalized UiO-66 metal framework material.

[0005] The basic principles of this invention are explained as follows:

[0006] This invention involves adding a composite regulator formed by organic acid and alcohol during the preparation of functionalized UiO-66 metal framework materials using zirconium source and organic ligands. The organic acid can: ① adjust the pH of the reaction system, thereby affecting the solubility, coordination environment, and reaction rate of metal ions, thus controlling crystal growth and crystallinity; ② form stable complexes with metal ions, preventing premature precipitation or aggregation of metal ions, helping to maintain the uniform distribution and reactivity of metal ions, and promoting crystal nucleation and growth; ③ change the coordination mode of the organic ligands, thereby affecting the size and distribution of pores. The alcohol can act as a surfactant, replacing water coordination in the crystal. When organic acid and alcohol are used in combination, the regulator acts as a second linker, competing with the organic ligands for zirconium ion coordination, thereby regulating the pore structure, morphology, size, and defect structure of the functionalized UiO-66 metal framework material, increasing the adsorption sites and improving gas adsorption performance.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A first aspect of the present invention provides a functionalized UiO-66 metal framework material, comprising the following raw materials: a zirconium source, an organic ligand, and a modifier; wherein the modifier comprises an organic acid and an alcohol.

[0009] Preferably, the volume ratio of organic acid to alcohol in the regulator is 1:(3-25); more preferably, the volume ratio of organic acid to alcohol is 1:(15-25).

[0010] Preferably, the organic acid includes at least one of monocarboxylic acids and halocarboxylic acids; more preferably, the organic acid includes at least one of formic acid, acetic acid, and trifluoroacetic acid.

[0011] Preferably, the alcohol comprises a C1 to C6 alkyl alcohol; more preferably, the alcohol comprises at least one of methanol and ethanol.

[0012] Preferably, the molar ratio of the zirconium source to the organic ligand is 1:(0.8-1.2); more preferably, the molar ratio of the zirconium source to the organic ligand is 1:(0.9-1.1).

[0013] Preferably, the zirconium source includes at least one of zirconium chloride, zirconium acetate, and zirconium sulfate.

[0014] Preferably, the organic ligand comprises at least one of terephthalic acid, 2-aminoterephthalic acid, 2-methylterephthalic acid, 2-bromoterephthalic acid, 2-nitroterephthalic acid, and 2,4-dichloroterephthalic acid.

[0015] Preferably, the raw materials for preparing the functionalized UiO-66 metal framework material further include a polar aprotic solvent.

[0016] Preferably, the polar aprotic solvent includes at least one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP).

[0017] Preferably, the volume ratio of the polar aprotic solvent to the regulator is (1-10):1; more preferably, the volume ratio of the polar aprotic solvent to the regulator is (1-8):1.

[0018] A second aspect of the present invention provides a method for preparing the functionalized UiO-66 metal framework material described in the first aspect of the present invention, comprising the following steps:

[0019] S1. Dissolve the zirconium source and organic ligand in a solvent to obtain a homogeneous solution;

[0020] S2. The homogeneous solution is heated to obtain the functionalized UiO-66 metal framework material.

[0021] Preferably, in step S1, the process of dissolving the zirconium source and organic ligand in the solvent is aided by ultrasound.

[0022] Preferably, in step S2, the reaction temperature is 110–130°C; more preferably, the reaction temperature is 115–125°C.

[0023] Preferably, in step S2, the reaction time is 20-25 hours; more preferably, the reaction time is 23-25 ​​hours.

[0024] Preferably, in step S2, the heating rate is 1-3°C / min; more preferably, the heating rate is 2-3°C / min.

[0025] Preferably, in step S2, the reaction is carried out in a high-pressure reactor.

[0026] Preferably, in step S2, after the reaction is completed, the steps of cooling to room temperature, collecting the powder by filtration, and washing are further included.

[0027] Preferably, in step S2, the washing reagents include N,N-dimethylformamide and ethanol.

[0028] Preferably, in step S2, the washing operation involves soaking the powder obtained by vacuum filtration in N,N-dimethylformamide for 2-3 days, changing the solution once a day, and then washing it with ethanol 2-4 times.

[0029] Preferably, in step S2, after the washing is completed, a vacuum drying step is also included.

[0030] Preferably, the vacuum drying temperature is 110–130°C; more preferably, the vacuum drying temperature is 115–125°C.

[0031] Preferably, the vacuum drying time is 8 to 12 hours; more preferably, the vacuum drying time is 8 to 10 hours.

[0032] The third aspect of the present invention provides the application of the functionalized UiO-66 metal framework material described in the first aspect of the present invention in gas adsorption.

[0033] Preferably, the mass ratio of the functionalized UiO-66 metal skeleton material to the gas is 1:(0.3-1); more preferably, the mass ratio of the functionalized UiO-66 metal skeleton material to the gas is 1:(0.3-0.6).

[0034] Preferably, the gas comprises an acidic gas; more preferably, the gas comprises HCl gas.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] 1) The functionalized UiO-66 metal framework material provided by this invention has small particle size, large specific surface area, nano-disordered pore structure, abundant crystal defects, and good gas adsorption performance.

[0037] 2) The preparation method of the functionalized UiO-66 metal framework material provided by the present invention is simple. By adding an organic acid and alcohol composite regulator, the regulator acts as a second linker to compete with the organic ligand for coordination with zirconium ions, thereby controlling the pore structure, morphology, size and defect structure of the functionalized UiO-66 metal framework material. By selecting different organic ligands, functionalized UiO-66 metal framework materials with different functional groups modified and whose morphology, size and defect structure are easily controlled can be obtained. Attached Figure Description

[0038] Figure 1 The XRD patterns of the NH2-UiO-66 metal framework material in Examples 1-4 and Comparative Example 1 are shown.

[0039] Figure 2 SEM images of the NH2-UiO-66 metal framework material in Examples 1-4;

[0040] Figure 3 SEM image of the NH2-UiO-66 metal framework material in Comparative Example 1;

[0041] Figure 4 TEM images of the NH2-UiO-66 metal framework material in Examples 1-4;

[0042] Figure 5 TGA images of the NH2-UiO-66 metal framework material in Examples 1-4 and Comparative Example 1;

[0043] Figure 6 The HCl adsorption curves of the NH2-UiO-66 metal framework material in Examples 1-4 and Comparative Example 1 are shown. Detailed Implementation

[0044] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments and comparative examples are all available from conventional commercial sources or can be obtained by existing technical methods. Unless otherwise specified, the test or experimental methods are conventional methods in the art.

[0045] Example 1

[0046] This embodiment provides an NH2-UiO-66 metal framework material, and the preparation steps are as follows:

[0047] S1. Dissolve 0.686 mmol ZrCl4 and 0.686 mmol 2-aminoterephthalic acid in a mixed solution consisting of 40 mL N,N-dimethylformamide, 1.176 mL acetic acid and 4 mL methanol, stir continuously and sonicate to obtain a homogeneous solution;

[0048] S2. Place the homogeneous solution obtained in step S1 in a high-pressure reactor, heat it to 120°C at a rate of 2°C / min, and continue the reaction at 120°C for 24 hours. After the reaction is completed, allow it to cool naturally to room temperature. Collect the powder by filtration, and soak the powder in N,N-dimethylformamide for 3 days, changing the solution once a day. Then wash it 3 times with ethanol at room temperature. Dry the washing product under vacuum at 120°C overnight to obtain activated NH2-UiO-66, denoted as NH2-UiO-66-10M.

[0049] Example 2

[0050] This embodiment provides an NH2-UiO-66 metal framework material, and the preparation steps are as follows:

[0051] S1. Dissolve 0.686 mmol ZrCl4 and 0.686 mmol 2-aminoterephthalic acid in a mixed solution consisting of 40 mL N,N-dimethylformamide, 1.176 mL acetic acid and 12 mL methanol, stir continuously and sonicate to obtain a homogeneous solution;

[0052] S2. Place the homogeneous solution obtained in step S1 in a high-pressure reactor, heat it to 120°C at a rate of 2°C / min, and continue the reaction at 120°C for 24 hours. After the reaction is completed, allow it to cool naturally to room temperature. Collect the powder by filtration, and soak the powder in N,N-dimethylformamide for 3 days, changing the solution once a day. Then wash it 3 times with ethanol at room temperature. Dry the washing product under vacuum at 120°C overnight to obtain activated NH2-UiO-66, denoted as NH2-UiO-66-30M.

[0053] Example 3

[0054] This embodiment provides an NH2-UiO-66 metal framework material, and the preparation steps are as follows:

[0055] S1. Dissolve 0.686 mmol ZrCl4 and 0.686 mmol 2-aminoterephthalic acid in a mixed solution consisting of 40 mL N,N-dimethylformamide, 1.176 mL acetic acid and 20 mL methanol, stir continuously and sonicate to obtain a homogeneous solution;

[0056] S2. Place the homogeneous solution obtained in step S1 in a high-pressure reactor, heat it to 120°C at a rate of 2°C / min, and continue the reaction at 120°C for 24 hours. After the reaction is completed, allow it to cool naturally to room temperature. Collect the powder by filtration, and soak the powder in N,N-dimethylformamide for 3 days, changing the solution once a day. Then wash it 3 times with ethanol at room temperature. Dry the washing product under vacuum at 120°C overnight to obtain activated NH2-UiO-66, denoted as NH2-UiO-66-50M.

[0057] Example 4

[0058] This embodiment provides an NH2-UiO-66 metal framework material, and the preparation steps are as follows:

[0059] S1. Dissolve 0.686 mmol ZrCl4 and 0.686 mmol 2-aminoterephthalic acid in a mixed solution consisting of 40 mL N,N-dimethylformamide, 1.176 mL acetic acid and 28 mL methanol, stir continuously and sonicate to obtain a homogeneous solution;

[0060] S2. Place the homogeneous solution obtained in step S1 in a high-pressure reactor, heat it to 120°C at a rate of 2°C / min, and continue the reaction at 120°C for 24 hours. After the reaction is completed, allow it to cool naturally to room temperature. Collect the powder by filtration, and soak the powder in N,N-dimethylformamide for 3 days, changing the solution once a day. Then wash it 3 times with ethanol at room temperature. Dry the washing product under vacuum at 120°C overnight to obtain activated NH2-UiO-66, denoted as NH2-UiO-66-70M.

[0061] Comparative Example 1

[0062] This comparative example provides an NH2-UiO-66 metal framework material, and the preparation steps are as follows:

[0063] S1. Dissolve 0.686 mmol ZrCl4 and 0.686 mmol 2-aminoterephthalic acid in a mixed solution consisting of 40 mL N,N-dimethylformamide and 1.176 mL acetic acid, stir continuously and sonicate to obtain a homogeneous solution;

[0064] S2. Place the homogeneous solution obtained in step S1 in a high-pressure reactor, heat it to 120°C at a rate of 2°C / min, and continue the reaction at 120°C for 24 hours. After the reaction is completed, allow it to cool naturally to room temperature. Collect the powder by filtration, and soak the powder in N,N-dimethylformamide for 3 days, changing the solution once a day. Then wash it 3 times with ethanol at room temperature. Dry the washing product under vacuum at 120°C overnight to obtain activated NH2-UiO-66, denoted as NH2-UiO-66-0.

[0065] Material characterization and performance testing

[0066] 1. X-ray diffraction analysis was performed on the NH2-UiO-66 metal framework materials prepared in Examples 1-4 and Comparative Example 1:

[0067] Figure 1 Table 1 shows the XRD patterns of the NH2-UiO-66 metal skeleton material in Examples 1-4 and Comparative Example 1. Table 1 is a table of defect data for the NH2-UiO-66 metal skeleton material in Examples 1-4 and Comparative Example 1. Figure 1 As shown in Table 1, in Comparative Example 1, the metal framework material NH2-UiO-66-0 prepared with organic acid as a modifier has the highest diffraction intensity, indicating good crystal regularity and few defect structures. In Examples 1-4, the diffraction intensity of the metal framework material with organic acid and alcohol as composite modifiers gradually decreased, and the diffraction intensity of the metal framework material gradually decreased with the increase of alcohol content, indicating that the composite modifier of organic acid and alcohol is beneficial to reduce the crystal regularity of functionalized UiO-66 metal framework material, and the crystal defects increase with the increase of alcohol content.

[0068] Table 1. Defect data of NH2-UiO-66 metal framework material in Examples 1-4 and Comparative Example 1.

[0069]

[0070]

[0071] 2. Scanning electron microscopy (SEM) analysis was performed on the NH2-UiO-66 metal framework materials prepared in Examples 1-4 and Comparative Example 1:

[0072] Figure 2 The images shown are SEM images of the NH2-UiO-66 metal framework materials in Examples 1-4. Figure 2 (a) is a SEM image of NH2-UiO-66-10M in Example 1. Figure 2 (b) is a SEM image of NH2-UiO-66-30M in Example 2. Figure 2 (c) is a SEM image of NH2-UiO-66-50M in Example 3. Figure 2 (d) is the SEM image of NH2-UiO-66-70M in Example 4.

[0073] Figure 3 Table 2 shows the SEM images of the NH2-UiO-66 metal framework material in Comparative Example 1. Table 2 also presents the particle size statistics of the NH2-UiO-66 metal framework materials in Examples 1-4 and Comparative Example 1. Figure 2 , Figure 3 As shown in Table 2, the metal skeleton material NH2-UiO-66-0 prepared by using only organic acid as a regulator in Comparative Example 1 has a larger particle size and a regular surface with no obvious defects. In Examples 1-4, as the amount of alcohol in the regulator increases, the particle size of the material gradually decreases and the crystal defects increase. That is, as the amount of alcohol increases, the particle size of the NH2-UiO-66 metal skeleton material gradually decreases and the specific surface area gradually increases, which is beneficial to increasing the contact between the material and the gas.

[0074] Table 2. Particle size statistics of NH2-UiO-66 metal framework materials in Examples 1-4 and Comparative Example 1.

[0075] name Particle size (nm) Comparative Example 1 <![CDATA[NH2-UiO-66-0]]> 81.54 Example 1 <![CDATA[NH2-UiO-66-10M]]> 35.72 Example 2 <![CDATA[NH2-UiO-66-30M]]> 20.55 Example 3 <![CDATA[NH2-UiO-66-50M]]> 13.99 Example 4 <![CDATA[NH2-UiO-66-70M]]> 12.67

[0076] 3. Transmission electron microscopy (TEM) was performed on the NH2-UiO-66 metal framework materials prepared in Examples 1-4:

[0077] Figure 4 These are TEM images of the NH2-UiO-66 metal framework material in Examples 1-4, where... Figure 4 (a) is a TEM image of NH2-UiO-66-10M in Example 1. Figure 4 (b) is a TEM image of NH2-UiO-66-30M in Example 2. Figure 4 (c) is a TEM image of NH2-UiO-66-50M in Example 3. Figure 4 (d) is a TEM image of NH2-UiO-66-70M in Example 4. Figure 4As can be seen from Examples 1-4, as the amount of alcohol in the regulator increases, the NH2-UiO-66 particles assemble to form a certain nano-disordered pore structure (secondary structure). This structure is beneficial for the material to liquefy the gas during adsorption, thereby increasing the gas adsorption capacity.

[0078] 4. Pore structure analysis was performed on the NH2-UiO-66 metal framework materials prepared in Examples 1-4 and Comparative Example 1:

[0079] Table 3 shows the pore volume data of the NH2-UiO-66 metal framework material in Examples 1-4 and Comparative Example 1. As can be seen from Table 3, the pore volume of NH2-UiO-66 increases with the increase of the amount of methanol as a regulator. This is attributed to the formation of a large number of mesopores or macropores by the assembly of NH2-UiO-66 particles. The increase in pore volume is beneficial to improving the gas adsorption capacity of NH2-UiO-66.

[0080] Table 3. Pore volume data of NH2-UiO-66 metal framework materials in Examples 1-4 and Comparative Example 1.

[0081] name <![CDATA[Pore volume (m 3 / g)]]> Comparative Example 1 <![CDATA[NH2-UiO-66-0]]> 0.65 Example 1 <![CDATA[NH2-UiO-66-10M]]> 0.75 Example 2 <![CDATA[NH2-UiO-66-30M]]> 1.16 Example 3 <![CDATA[NH2-UiO-66-50M]]> 1.06 Example 4 <![CDATA[NH2-UiO-66-70M]]> 1.10

[0082] 5. Thermal stability analysis was performed on the NH2-UiO-66 metal framework materials prepared in Examples 1-4 and Comparative Example 1:

[0083] Figure 5 The TGA images of the NH2-UiO-66 metal framework materials in Examples 1-4 and Comparative Example 1 are provided by [the relevant authority / organization]. Figure 5 It can be seen that when the regulator contains alcohol solvent, the increased crystal defects negatively affect the thermal stability of the material. In Examples 1 and 2, the amount of alcohol solvent used was relatively small, and NH2-UiO-66 began to show significant mass loss at 400℃ and 500℃, respectively. In Examples 3 and 4, the trend of the material's thermal stability was basically consistent with that of NH2-UiO-66-0 prepared using only organic acid regulator in Comparative Example 1, and the change in thermal stability was relatively small. This indicates that in order to increase crystal defects while ensuring good thermal stability of the material, the amount of alcohol in the regulator needs to be controlled. When the volume ratio of organic acid to alcohol is 1:(15~25), the material performance is better.

[0084] 6. The HCl gas adsorption performance of the NH2-UiO-66 metal framework materials prepared in Examples 1-4 and Comparative Example 1 was tested:

[0085] The testing device consists of an air intake system, a rectification and speed control system, a stirring and heating system, a drying system, a sample placement and absorption platform, and an exhaust gas treatment system. Figure 6 The figures show the HCl adsorption curves of the NH2-UiO-66 metal framework materials in Examples 1-4 and Comparative Example 1. Figure 6 It can be seen that in Comparative Example 1, NH2-UiO-66-0 prepared using only organic acid as a regulator reached adsorption saturation 20 minutes after adsorption began, with an adsorption capacity of approximately 0.2 g (HCl) / g (NH2-UiO-66-0). In Examples 1-4, after using a composite regulator of organic acid and alcohol, the HCl adsorption capacity of the NH2-UiO-66 metal framework material became stronger, and the adsorption capacity of HCl gas at adsorption saturation was greater than 0.3 g (HCl) / g (NH2-UiO-66). This indicates that the addition of alcohol to the regulator improved the HCl gas adsorption performance of the NH2-UiO-66 metal framework material, and the adsorption capacity of the material for HCl gas gradually increased with the increase of alcohol content in the regulator.

[0086] The functionalized UiO-66 metal framework material provided by this invention, compared with UiO-66 metal framework materials using only organic acids as modifiers, has smaller particle size, larger specific surface area, a nano-disordered pore structure, more abundant crystal defects, and better gas adsorption performance. The preparation method of the functionalized UiO-66 metal framework material is simple; by selecting different organic ligands, functionalized UiO-66 metal framework materials other than NH2-UiO-66 can be formed, and all of these methods allow for easy control of the material's morphology, size, and defect structure, thereby improving gas adsorption performance.

Claims

1. A functionalized UiO-66 metal framework material, characterized in that, It is prepared from the following raw materials: zirconium source, organic ligand, modifier and polar aprotic solvent; the modifier is a mixture of organic acid and alcohol in a volume ratio of 1: (15~25); the polar aprotic solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

2. The functionalized UiO-66 metal framework material according to claim 1, characterized in that, The organic acid includes at least one of monocarboxylic acids and halocarboxylic acids.

3. The functionalized UiO-66 metal framework material according to claim 1, characterized in that, The alcohols include C1 to C6 alkyl alcohols.

4. The functionalized UiO-66 metal framework material according to claim 1, characterized in that, The molar ratio of the zirconium source to the organic ligand is 1:(0.8~1.2).

5. The functionalized UiO-66 metal framework material according to claim 1, characterized in that, The zirconium source includes at least one of zirconium chloride, zirconium acetate, and zirconium sulfate; And / or, the organic ligand comprises at least one of terephthalic acid, 2-aminoterephthalic acid, 2-methylterephthalic acid, 2-bromoterephthalic acid, 2-nitroterephthalic acid, and 2,4-dichloroterephthalic acid.

6. The functionalized UiO-66 metal framework material according to claim 1, characterized in that, The volume ratio of the polar aprotic solvent to the modifier is (1~10):

1.

7. The method for preparing the functionalized UiO-66 metal framework material according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Dissolve the zirconium source and organic ligand in a polar aprotic solvent and a modifier to obtain a homogeneous solution; S2. The homogeneous solution is heated to obtain the functionalized UiO-66 metal framework material.

8. The preparation method according to claim 7, characterized in that, In step S2, the reaction temperature is 110~130℃; And / or, the reaction time is 20-25 hours; And / or, the heating rate is 1~3℃ / min.

9. The application of the functionalized UiO-66 metal framework material according to any one of claims 1-6 in the adsorption of acidic gases.

10. The application according to claim 9, characterized in that, The mass ratio of the functionalized UiO-66 metal skeleton material to the acidic gas is 1:(0.3~1).

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