Functionalized UiO-66 metal framework material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of metal organic framework materials, and discloses a functionalized UiO-66 metal framework material as well as a preparation method and application thereof. The functionalized UiO-66 metal framework material is prepared from the following raw materials: a zirconium source, an organic ligand, a polar aprotic solvent and a regulator, the regulator comprises an organic acid and an alcohol. The functionalized UiO-66 metal framework material provided by the invention has the advantages of small particle size, large specific surface area, nanometer disordered pore structure, abundant crystal defects and good gas adsorption performance. The preparation method of the material is simple in steps, an organic acid and alcohol composite conditioning agent is added, the conditioning agent serves as a second connecting body and competes with organic ligands to coordinate with zirconium ions, and therefore the pore channel structure, the morphology size and the defect structure of the functionalized UiO-66 metal framework material are regulated and controlled, and the functional UiO-66 metal framework material is obtained 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] The present invention relates to the technical field of metal organic framework materials, and in particular to a functionalized UiO-66 metal framework material and a preparation method and application thereof. Background Art

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

[0003] Functionalized UiO-66 metal skeleton materials usually have good gas adsorption performance. For example, the NH2-UiO-66 metal skeleton material prepared by amino-containing ligands and zirconium ions has hexagonal channels and two pore structures with diameters of 0.8nm and 1.1nm. Compared with UiO-66, NH2-UiO-66 has a larger specific surface area (1000m 2 / g or more) and pore volume (0.5cm 3 / g); at the same time, the amino group gives NH2-UiO-66 hydrogen bonding sites, which improves the material's gas adsorption capacity through strong interactions such as hydrogen bonding. However, the existing functionalized UiO-66 metal skeleton materials have defects such as uneven particle size, large particle size, and fewer gas adsorption sites. Summary of the invention

[0004] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, one of the purposes of the present invention is to provide a functionalized UiO-66 metal skeleton material; the second purpose of the present invention is to provide a preparation method of the functionalized UiO-66 metal skeleton material; the third purpose of the present invention is to provide the application of the functionalized UiO-66 metal skeleton material.

[0005] The basic principle of the present invention is described as follows:

[0006] The present invention adds a composite regulator formed by organic acid and alcohol in the process of preparing a functionalized UiO-66 metal skeleton material using a zirconium source and an organic ligand as raw materials. The organic acid can ① adjust the pH value of the reaction system, thereby affecting the solubility, coordination environment and reaction rate of metal ions, thereby controlling the growth and crystallinity of the crystal; ② form a stable complex with the metal ions to prevent the metal ions from precipitating or agglomerating prematurely, help maintain the uniform distribution and reaction activity of the metal ions, and promote the nucleation and growth of the crystal; ③ change the coordination mode of the organic ligand, thereby affecting the size and distribution of the pore size. Alcohol can act as a surfactant to replace the coordination of water in the crystal. When the organic acid and alcohol are used in combination, the regulator acts as a second connector to compete with the organic ligand for the coordination of zirconium ions, thereby regulating the pore structure, morphology size and defect structure of the functionalized UiO-66 metal skeleton material, increasing the adsorption sites of the material, and improving the gas adsorption performance.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

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

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

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

[0011] Preferably, the alcohol includes C1-C6 alkyl alcohol; more preferably, the alcohol includes 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); further 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 includes 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 also 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; further preferably, the volume ratio of the polar aprotic solvent to the regulator is (1-8):1.

[0018] The second aspect of the present invention provides a method for preparing the functionalized UiO-66 metal skeleton material according to the first aspect of the present invention, comprising the following steps:

[0019] S1, dissolving a zirconium source and an organic ligand in a solvent to obtain a homogeneous solution;

[0020] S2. The homogeneous solution is subjected to a temperature-raising reaction to obtain the functionalized UiO-66 metal skeleton material.

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

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

[0023] Preferably, in step S2, the reaction time is 20 to 25 hours; further preferably, the reaction time is 23 to 25 hours.

[0024] Preferably, in step S2, the heating rate is 1-3°C / min; further 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 powder by suction filtration, and washing are also included.

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

[0028] Preferably, in step S2, the specific operation of washing is to soak the powder obtained by filtration in N,N-dimethylformamide for 2 to 3 days, replace the solution once a day, and then wash with ethanol for 2 to 4 times.

[0029] Preferably, in the 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; further preferably, the vacuum drying time is 8 to 10 hours.

[0032] The third aspect of the present invention provides the use of the functionalized UiO-66 metal skeleton 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); further 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 acidic gas; further preferably, the gas comprises HCl gas.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

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

[0037] 2) The preparation method of the functionalized UiO-66 metal skeleton material provided by the present invention has simple steps. By adding an organic acid and alcohol composite regulator, the regulator is used as a second connector to compete with the organic ligand for the coordination of zirconium ions, thereby regulating the pore structure, morphology size and defect structure of the functionalized UiO-66 metal skeleton material. By selecting different organic ligands, functionalized UiO-66 metal skeleton materials modified with different functional groups and easily regulated morphology size and defect structure can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 XRD diagram of the NH2-UiO-66 metal skeleton material in Examples 1-4 and Comparative Example 1;

[0039] Figure 2 This is the SEM image of the NH2-UiO-66 metal skeleton material in Examples 1-4;

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

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

[0042] Figure 5 It is the TGA graph of the NH2-UiO-66 metal skeleton material in Examples 1-4 and Comparative Example 1;

[0043] Figure 6 This is the HCl adsorption curve of the NH2-UiO-66 metal skeleton material in Examples 1-4 and Comparative Example 1. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below by specific examples. Unless otherwise specified, the raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial sources or can be obtained by prior art methods. Unless otherwise specified, the experiments or test methods are conventional methods in the art.

[0045] Example 1

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

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

[0048] S2. The homogeneous solution obtained in step S1 is placed in a high-pressure reactor, and the temperature is increased to 120°C at a rate of 2°C / min, and the reaction is continued at 120°C for 24 hours. After the reaction is completed, the mixture is naturally cooled to room temperature. The powder is collected by filtration, and the powder is soaked in N,N-dimethylformamide for 3 days, and the solution is changed once a day. The powder is then washed with ethanol for 3 times at room temperature, and the washed product is vacuum dried at 120°C overnight to obtain activated NH2-UiO-66, which is recorded as NH2-UiO-66-10M.

[0049] Example 2

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

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

[0052] S2. The homogeneous solution obtained in step S1 is placed in a high-pressure reactor, and the temperature is increased to 120°C at a rate of 2°C / min, and the reaction is continued at 120°C for 24 hours. After the reaction is completed, the mixture is naturally cooled to room temperature. The powder is collected by filtration, and the powder is soaked in N,N-dimethylformamide for 3 days, and the solution is changed once a day. The powder is then washed with ethanol for 3 times at room temperature, and the washed product is vacuum dried at 120°C overnight to obtain activated NH2-UiO-66, which is recorded as NH2-UiO-66-30M.

[0053] Example 3

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

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

[0056] S2. The homogeneous solution obtained in step S1 is placed in a high-pressure reactor, and the temperature is increased to 120°C at a rate of 2°C / min, and the reaction is continued at 120°C for 24 hours. After the reaction is completed, the mixture is naturally cooled to room temperature. The powder is collected by filtration, and the powder is soaked in N,N-dimethylformamide for 3 days, and the solution is changed once a day. The powder is then washed with ethanol for 3 times at room temperature, and the washed product is vacuum dried at 120°C overnight to obtain activated NH2-UiO-66, which is recorded as NH2-UiO-66-50M.

[0057] Example 4

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

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

[0060] S2. The homogeneous solution obtained in step S1 is placed in a high-pressure reactor, and the temperature is increased to 120°C at a rate of 2°C / min, and the reaction is continued at 120°C for 24 hours. After the reaction is completed, the mixture is naturally cooled to room temperature. The powder is collected by filtration, and the powder is soaked in N,N-dimethylformamide for 3 days, and the solution is changed once a day. The powder is then washed with ethanol for 3 times at room temperature, and the washed product is vacuum dried at 120°C overnight to obtain activated NH2-UiO-66, which is recorded as NH2-UiO-66-70M.

[0061] Comparative Example 1

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

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

[0064] S2. The homogeneous solution obtained in step S1 is placed in a high-pressure reactor, and the temperature is increased to 120°C at a rate of 2°C / min, and the reaction is continued at 120°C for 24 hours. After the reaction is completed, the mixture is naturally cooled to room temperature. The powder is collected by filtration, and the powder is soaked in N,N-dimethylformamide for 3 days, and the solution is changed once a day. The powder is then washed with ethanol for 3 times at room temperature, and the washed product is vacuum dried at 120°C overnight to obtain activated NH2-UiO-66, which is recorded as NH2-UiO-66-0.

[0065] Material Characterization and Performance Testing

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

[0067] Figure 1 is the XRD diagram of the NH2-UiO-66 metal skeleton material in Examples 1-4 and Comparative Example 1, and Table 1 is the defect data table of the NH2-UiO-66 metal skeleton material in Examples 1-4 and Comparative Example 1, Figure 1 As can be seen from Table 1, the diffraction intensity of the metal skeleton material NH2-UiO-66-0 prepared with only organic acid as the regulator in Comparative Example 1 is the highest, indicating that the crystal has good regularity and few defective structures; in Examples 1-4, the diffraction intensity of the metal skeleton material with organic acid and alcohol as the composite regulator gradually decreases, and with the increase of the amount of alcohol, the diffraction intensity of the metal skeleton material shows a gradually decreasing trend, indicating that the composite regulator of organic acid and alcohol is beneficial to reducing the crystal regularity of the functionalized UiO-66 metal skeleton material, and with the increase of the amount of alcohol, the defects of the crystal increase.

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

[0069]

[0070]

[0071] 2. Scanning electron microscopy test was performed on the NH2-UiO-66 metal skeleton materials prepared in Examples 1-4 and Comparative Example 1:

[0072] Figure 2 is the SEM image of the NH2-UiO-66 metal skeleton material in Examples 1-4, wherein: Figure 2 (a) is the SEM image of NH2-UiO-66-10M in Example 1, Figure 2 (b) is the SEM image of NH2-UiO-66-30M in Example 2, Figure 2 (c) is the 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 is the SEM image of the NH2-UiO-66 metal skeleton material in Example 1. Table 2 is the particle size statistics of the NH2-UiO-66 metal skeleton material in Examples 1-4 and Comparative Example 1. Figure 2 , Figure 3 As can be seen from Table 2, in Comparative Example 1, the metal skeleton material NH2-UiO-66-0 prepared with only organic acid as the regulator has a larger particle size, a regular surface, and 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 increase the contact between the material and the gas.

[0074] Table 2 Particle size statistics of NH2-UiO-66 metal skeleton 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. The NH2-UiO-66 metal skeleton material prepared in Examples 1-4 was tested by transmission electron microscopy:

[0077] Figure 4 TEM image of the NH2-UiO-66 metal skeleton material in Examples 1-4, wherein: Figure 4 (a) is the TEM image of NH2-UiO-66-10M in Example 1, Figure 4 (b) is the TEM image of NH2-UiO-66-30M in Example 2, Figure 4 (c) is the TEM image of NH2-UiO-66-50M in Example 3, Figure 4 (d) is the TEM image of NH2-UiO-66-70M in Example 4. Figure 4It can be seen that in 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), which is beneficial for the material to liquefy the gas when adsorbing the gas, thereby increasing the gas adsorption capacity.

[0078] 4. The pore structure analysis of the NH2-UiO-66 metal skeleton material prepared in Examples 1-4 and Comparative Example 1 was performed:

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

[0080] Table 3 Pore volume data of NH2-UiO-66 metal skeleton 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 of the NH2-UiO-66 metal skeleton materials prepared in Examples 1-4 and Comparative Example 1:

[0083] Figure 5 is the TGA graph of the NH2-UiO-66 metal skeleton material in Examples 1-4 and Comparative Example 1, Figure 5 It can be seen that when the regulator contains an alcohol solvent, the thermal stability of the material is adversely affected to a certain extent due to the increase in crystal defects. In Examples 1 and 2, the amount of alcohol solvent used is relatively small, and NH2-UiO-66 begins to show obvious mass loss at 400°C and 500°C, respectively. In Examples 3 and 4, the change trend of the thermal stability of the material is basically consistent with that of NH2-UiO-66-0 prepared by using only an organic acid regulator in Comparative Example 1, and the change in thermal stability is relatively small, indicating that in order to increase the crystal defects while ensuring that the material has good thermal stability, it is necessary to control the amount of alcohol in the regulator. When the volume ratio of organic acid to alcohol is 1: (15-25), the performance of the material is better.

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

[0085] The test device consists of an air intake system, a rectification and speed control system, a stirring and heating system, a drying system, a sample absorption platform and an exhaust gas treatment system. Figure 6 is the HCl adsorption curve of the NH2-UiO-66 metal skeleton material in Examples 1-4 and Comparative Example 1, Figure 6 It can be seen that the NH2-UiO-66-0 prepared with only organic acid as the regulator in Comparative Example 1 reaches adsorption saturation 20 minutes after the start of adsorption, and the adsorption amount of HCl gas is about 0.2g (HCl) / g (NH2-UiO-66-0). In Examples 1-4, after using the composite regulator of organic acid and alcohol, the HCl gas adsorption capacity of the NH2-UiO-66 metal skeleton material becomes stronger, and the adsorption amount of HCl gas at adsorption saturation is greater than 0.3g (HCl) / g (NH2-UiO-66), indicating that the addition of alcohol in the regulator improves the HCl gas adsorption performance of the NH2-UiO-66 metal skeleton material, and with the increase of the amount of alcohol in the regulator, the adsorption amount of HCl gas by the material gradually increases.

[0086] The functionalized UiO-66 metal skeleton material provided by the present invention has a smaller particle size, a larger specific surface area, a nano-disordered pore structure, more abundant crystal defects, and better gas adsorption performance compared to the UiO-66 metal skeleton material using only organic acid as a regulator. The preparation method of the functionalized UiO-66 metal skeleton material has simple steps. By selecting different organic ligands, functionalized UiO-66 metal skeleton materials other than NH2-UiO-66 can be formed, and the morphology size and defect structure of the material can be easily controlled and the gas adsorption performance can be improved.

Claims

1. A functionalized UiO-66 metal skeleton material, It is characterized in that The preparation method comprises the following raw materials: a zirconium source, an organic ligand and a regulator; the regulator comprises an organic acid and an alcohol.

2. The functionalized UiO-66 metal skeleton material according to claim 1, It is characterized in that In the regulator, the volume ratio of organic acid to alcohol is 1:(3-25).

3. The functionalized UiO-66 metal skeleton material according to claim 1, It is characterized in that The organic acid includes at least one of a monocarboxylic acid and a halogenated carboxylic acid; And / or, the alcohol comprises a C1-C6 alkyl alcohol.

4. The functionalized UiO-66 metal skeleton material according to claim 1, It is 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 skeleton material according to claim 1, It is characterized in that The zirconium source includes at least one of zirconium chloride, zirconium acetate and zirconium sulfate; And / or, the organic ligand includes 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 skeleton material according to claim 1, It is characterized in that The raw materials for preparing the functionalized UiO-66 metal framework material also include a polar aprotic solvent; Preferably, the volume ratio of the polar aprotic solvent to the regulator is (1-10):

1.

7. A method for preparing the functionalized UiO-66 metal skeleton material according to any one of claims 1 to 6, It is characterized in that The following steps are involved: S1, dissolving a zirconium source and an organic ligand in a polar aprotic solvent and a regulator to obtain a homogeneous solution; S2. The homogeneous solution is subjected to a temperature-raising reaction to obtain the functionalized UiO-66 metal skeleton material.

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

9. Use of the functionalized UiO-66 metal skeleton material according to any one of claims 1 to 6 in gas adsorption.

10. The use according to claim 9, It is characterized in that The mass ratio of the functionalized UiO-66 metal skeleton material to the gas is 1:(0.3-1); Preferably, the gas comprises an acid gas.

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