"Defective" Metal-Organic Framework Catalysts Induced by Persulfate Etching, Preparation Method and Application Thereof

Abstract

The present invention discloses a "defect-type" metal-organic framework catalyst induced by persulfate etching, its preparation method and application; putting the metal-organic framework material and persulfate into a reaction vessel, evacuating and then introducing an inert gas, carrying out chemical vapor deposition reaction at 120-180 °C for 3-12 h, washing the obtained solid product with pure water and ethanol, and drying to obtain the "defect-type" metal-organic framework catalyst induced by persulfate etching; by adjusting the preparation conditions, its TOFs for tetracycline hydrochloride can reach 1.847 h ‑1 , the preparation process of the present invention is simple, the material performance is excellent, and it has broad application prospects in the field of catalytic oxidation.

Description

Technical Field

[0001] The present invention relates to a functionalized defective catalytic material, a preparation method and an application thereof, and particularly relates to a "defective" metal-organic framework (MOF) catalyst etched and mutated by persulfate, a gas-phase deposition method for modification thereof, and an application in a catalytic oxidation reaction. Background Art

[0002] Catalytic oxidation technology has been widely applied in the fields of energy supply, pharmaceutical and chemical industry, agriculture, handicraft industry, environmental protection, etc. As a catalytic material with a customizable channel structure, large surface area and versatility, MOFs have attracted much attention in the field of catalytic oxidation technology. However, the disadvantage of pure MOFs is that due to the rapid recombination of electron-hole pairs, the collection is limited or the stability is insufficient, which hinders the improvement of catalytic efficiency. Therefore, modifying pure MOF catalysts to improve their catalytic performance has become the key to accelerating the catalytic oxidation reaction.

[0003] Currently, antibiotics are widely used in the prevention and treatment of human and veterinary diseases, as well as in animal feeding additives. Antibiotics have the characteristics of complex composition, stable structure and difficult degradation. Most traditional water treatment technologies still cannot meet the national permitted discharge standards for the removal of antibiotics and other pollutants. Therefore, it has become increasingly urgent to remove antibiotics from the water environment, and it is of great significance to develop an economic, efficient, green and environmentally friendly antibiotic treatment technology. Currently, the commonly used method for degrading organic pollutants in water is to use advanced oxidation technologies (AOPs), specifically a class of technologies that oxidize and degrade organic substances in water with hydroxyl radicals as reactive oxygen species, mainly including Fenton, photo(electro)Fenton, ozone oxidation, wet oxidation, etc. Among them, the Fenton reaction uses H2O2 as an oxidant and Fe 2+ as a catalyst to generate hydroxyl radicals, which can oxidize and degrade low-concentration organic pollutants at normal temperature and pressure. Therefore, it is crucial to select a catalyst suitable for a better pH application range, higher target pollutant selectivity and a longer half-life.

[0004] Due to the limitations of pure MOFs materials, doped defective materials have stood out in recent research. Patent documents CN113617350A and CN114824223A respectively carried out plasma etching on carbon materials to obtain defective carbon materials and realized surface defects and materials with high sulfur defect vacancies by using N-doped carbon microspheres as templates; patent documents CN115090299A and CN114959636A treated ZIS prepared by the hydrothermal method with a reducing agent to prepare a ZIS semiconductor photocatalytic material with S defects and prepared two-dimensional transition metal sulfides by chemical vapor deposition. Although defective materials have been widely used as catalysts in theoretical research, there are still many problems that need to be urgently solved in actual use: (1) Most of the reported doped defective catalysts are C-based materials, and due to the limitations of the materials themselves, the catalytic effect is limited; (2) Most of the reported doped defective catalysts etch inorganic substances such as MnS and ZIS. The substances themselves are relatively small in size, and it is difficult to produce and recycle them on a large scale by chemical vapor deposition. The value improvement of similar semiconductor materials is low, and the application range is limited. These drawbacks have severely restricted the wide application of doped defective catalysts in the catalytic field. Summary of the Invention

[0005] The purpose of the present invention is to provide a functionalized "defective" metal-organic framework heterogeneous catalyst for catalytic oxidation reactions and a preparation method thereof. The present invention first synthesizes metal-organic framework materials MIL-53(Fe) and Cu-BTC by the hydrothermal method, and then forms a defective structure on the surface of the MOFs by means of chemical vapor deposition combined with persulfate etching.

[0006] The present invention solves the problems that the existing doped defective materials are small in size, difficult to recycle, and uneconomical for batch production. The persulfate etching modification is carried out by chemical vapor deposition, providing an idea for the modification of MOFs catalysts.

[0007] The technical solution of the present invention is as follows:

[0008] A preparation method of a persulfate-etched mutagenic "defective" metal-organic framework catalyst, comprising:

[0009] Put the metal-organic framework material (MOFs) and persulfate into a reaction vessel, evacuate and then introduce an inert gas, and carry out a chemical vapor deposition reaction at 120-180 °C for 3-12 h. The obtained solid product is washed with pure water and ethanol, and dried to obtain the persulfate-etched mutagenic "defective" metal-organic framework catalyst;

[0010] Wherein,

[0011] The metal centers of the metal-organic framework materials are Fe, Cu, or a mixture of the two in any proportion. Specific metal-organic framework materials include, for example, MIL-53(Fe) or Cu-BTC;

[0012] The persulfate is selected from one or more of potassium persulfate, sodium persulfate, and ammonium persulfate, or a mixture of any proportion of two or more;

[0013] The mass ratio of the metal-organic framework material to the persulfate is 1:0.5 - 5, preferably 1:2;

[0014] The inert gas can be nitrogen or argon, and the ventilation rate is 50 - 80 cm / s;

[0015] Preferably, the temperature of chemical vapor deposition is 150 °C and the time is 6 h.

[0016] In the chemical vapor deposition process of the present invention, at a high temperature of 120 - 180 °C, the persulfate will undergo thermal decomposition, releasing sulfur dioxide (SO2) gas. This gas reacts chemically with the metal surface, resulting in the etching of the metal and the formation of oxygen vacancies. The etching mechanism of SO2 involves reactions with metals to form metal sulfides. And with the gas flow, part of the sulfates can also chemically etch the surface of the MOF.

[0017] The present invention relates to a "defect-type" metal-organic framework catalyst induced by persulfate etching prepared by the above preparation method.

[0018] The "defect-type" metal-organic framework catalyst induced by persulfate etching of the present invention can be used in catalytic oxidation reactions. Specifically, for example, it is used to catalyze the oxidation degradation of tetracycline hydrochloride by hydrogen peroxide.

[0019] Compared with the prior art, the advantages of the present invention are as follows:

[0020] 1. By means of chemical vapor deposition (which can be repeated), non-metallic materials such as sulfur are doped on the surface and pores of the metal-organic framework material, and mutagenesis is carried out through the temperature and gas flow during the vapor deposition process to obtain a defective morphology structure. This provides an idea for doping materials and expands the application field of metal-organic framework catalysts.

[0021] 2. By adjusting the preparation conditions, the TOFs of the metal-organic framework catalyst for tetracycline hydrochloride can reach 1.847 h -1 , the preparation process of the present invention is simple, the material performance is excellent, and it has broad prospects in the field of catalytic oxidation applications.

[0022] 3. The catalyst can be recovered by simple physical methods such as centrifugation and filtration, which is energy-saving and environmentally friendly. And the reuse effect is good for multiple times, having good potential for industrial application. Description of the Drawings

[0023] Figure 1 : SEM image of Example 7 of the present invention.

[0024] Figure 2 : TEM image of Example 7 of the present invention.

[0025] Figure 3 : FTIR spectra of Example 7 and Comparative Example 1 of the present invention.

[0026] Figure 4 : XRD patterns of Example 7 and Comparative Example 1 of the present invention. Detailed implementation mode

[0027] The present invention will be described in detail below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments. Without departing from the content and scope of the present invention, all variations should be included within the technical scope of the present invention.

[0028] Example 1

[0029] 0.2 g of MIL-53(Fe) and 0.1 g of sodium persulfate were placed in a polytetrafluoroethylene reactor at a mass ratio of 1:0.5. After evacuating, argon was introduced at 120 °C for chemical vapor deposition reaction for 6 h. Then, it was washed 3 times with water and ethanol respectively, centrifuged, and dried at 60 °C for 12 h to obtain S-doped mutagenic Fe-based MOFs with a rose flower skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(Na)-0.5 as the carrier).

[0030] Example 2

[0031] 0.2 g of MIL-53(Fe) and 0.2 g of sodium persulfate were placed in a polytetrafluoroethylene reactor at a mass ratio of 1:1. Argon was introduced at 120 °C for chemical vapor deposition reaction for 6 h. Then, it was washed 3 times with water and ethanol respectively, centrifuged, and dried at 60 °C for 12 h to obtain S-doped mutagenic Fe-based MOFs with a rose flower skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(Na)-1 as the carrier).

[0032] Example 3

[0033] 0.1 g of MIL-53(Fe) and 0.2 g of sodium persulfate were placed in a polytetrafluoroethylene reactor at a mass ratio of 1:2. Argon was introduced at 120 °C for chemical vapor deposition reaction for 6 h. Then, it was washed 3 times with water and ethanol respectively, centrifuged, and dried at 60 °C for 12 h to obtain S-doped mutagenic Fe-based MOFs with a rose flower skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(Na)-2 as the carrier).

[0034] Example 4

[0035] Put 0.1 g of MIL-53(Fe) and 0.3 g of sodium persulfate in a mass ratio of 1:3 into a polytetrafluoroethylene reactor. Pass argon gas at 120 °C for 6 h for chemical vapor deposition reaction. Then wash with water and ethanol three times respectively, centrifuge, and dry at 60 °C for 12 h to obtain Fe-based MOFs with S-doped mutagenesis of rose skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(Na)-3 for this carrier).

[0036] Example 5

[0037] Put 0.1 g of MIL-53(Fe) and 0.4 g of sodium persulfate in a mass ratio of 1:4 into a polytetrafluoroethylene reactor. Pass argon gas at 120 °C for 6 h for chemical vapor deposition reaction. Then wash with water and ethanol three times respectively, centrifuge, and dry at 60 °C for 12 h to obtain Fe-based MOFs with S-doped mutagenesis of rose skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(Na)-4 for this carrier).

[0038] Example 6

[0039] Put 0.1 g of MIL-53(Fe) and 0.5 g of sodium persulfate in a mass ratio of 1:5 into a polytetrafluoroethylene reactor. Pass argon gas at 120 °C for 6 h for chemical vapor deposition reaction. Then wash with water and ethanol three times respectively, centrifuge, and dry at 60 °C for 12 h to obtain Fe-based MOFs with S-doped mutagenesis of rose skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(Na)-5 for this carrier).

[0040] Example 7

[0041] Put 0.1 g of MIL-53(Fe) and 0.2 g of sodium persulfate in a mass ratio of 1:2 into a polytetrafluoroethylene reactor. Pass argon gas at 150 °C for 6 h for chemical vapor deposition reaction. Then wash with water and ethanol three times respectively, centrifuge, and dry at 60 °C for 12 h to obtain Fe-based MOFs with S-doped mutagenesis of rose skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(Na)-150 for this carrier).

[0042] Example 8

[0043] Put 0.1 g of MIL-53(Fe) and 0.2 g of sodium persulfate in a mass ratio of 1:2 into a polytetrafluoroethylene reactor. Pass argon gas at 180 °C for 6 h for chemical vapor deposition reaction. Then wash with water and ethanol three times respectively, centrifuge, and dry at 60 °C for 12 h to obtain Fe-based MOFs with S-doped mutagenesis of rose skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(Na)-180 for this carrier).

[0044] Example 9

[0045] 0.1 g of MIL-53(Fe) and 0.2 g of sodium persulfate were placed in a polytetrafluoroethylene reactor at a mass ratio of 1:2, and argon was introduced at 150 °C for chemical vapor deposition reaction for 3 h. Then, they were washed 3 times with water and ethanol respectively, centrifuged, and dried at 60 °C for 12 h to obtain Fe-based MOFs with S-doped mutagenesis of rose skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(Na)-3h for this carrier).

[0046] Example 10

[0047] 0.1 g of MIL-53(Fe) and 0.2 g of sodium persulfate were placed in a polytetrafluoroethylene reactor at a mass ratio of 1:2, and argon was introduced at 150 °C for chemical vapor deposition reaction for 9 h. Then, they were washed 3 times with water and ethanol respectively, centrifuged, and dried at 60 °C for 12 h to obtain Fe-based MOFs with S-doped mutagenesis of rose skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(Na)-9h for this carrier).

[0048] Example 11

[0049] 0.1 g of MIL-53(Fe) and 0.2 g of sodium persulfate were placed in a polytetrafluoroethylene reactor at a mass ratio of 1:2, and argon was introduced at 150 °C for chemical vapor deposition reaction for 12 h. Then, they were washed 3 times with water and ethanol respectively, centrifuged, and dried at 60 °C for 12 h to obtain Fe-based MOFs with S-doped mutagenesis of rose skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(Na)-12h for this carrier).

[0050] Example 12

[0051] 0.1 g of Cu-BTC and 0.2 g of sodium persulfate were placed in a polytetrafluoroethylene reactor at a mass ratio of 1:2, and argon was introduced at 150 °C for chemical vapor deposition reaction for 9 h. Then, they were washed 3 times with water and ethanol respectively, centrifuged, and dried at 60 °C for 12 h to obtain a Cu-based material with S-doped defective blue rose skeleton structure (Aps-Cu-BTC(Na)).

[0052] Example 13

[0053] 0.1 g of MIL-53(Fe) and 0.2 g of potassium persulfate were placed in a polytetrafluoroethylene reactor at a mass ratio of 1:2, and argon was introduced at 150 °C for chemical vapor deposition reaction for 6 h. Then, they were washed 3 times with water and ethanol respectively, centrifuged, and dried at 60 °C for 12 h to obtain Fe-based MOFs with S-doped mutagenesis of rose skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(K) for this carrier).

[0054] Example 14

[0055] Put 0.1 g of MIL-53(Fe) and 0.2 g of ammonium persulfate in a polytetrafluoroethylene reactor at a mass ratio of 1:2, introduce argon at 150 °C for chemical vapor deposition reaction for 6 h, then wash 3 times with water and ethanol respectively, centrifuge, and dry at 60 °C for 12 h to obtain S-doped mutagenic Fe-based MOFs with a rose skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(NH4) as the carrier).

[0056] Example 15

[0057] Put 0.1 g of MIL-53(Fe) and 0.2 g of sodium persulfate in a polytetrafluoroethylene reactor at a mass ratio of 1:2, introduce nitrogen at 150 °C for chemical vapor deposition reaction for 6 h, then wash 3 times with water and ethanol respectively, centrifuge, and dry at 60 °C for 12 h to obtain S-doped mutagenic Fe-based MOFs with a rose skeleton structure (hereinafter represented by Sps-MIL-53(Fe)(Na)-N2 as the carrier).

[0058] Comparative Example 1 Preparation of MIL-53(Fe)

[0059] Put 1.663 g of terephthalic acid and 1.350 g of ferric chloride hexahydrate into a 50 mL polytetrafluoroethylene reaction kettle, add 25 mL of N,N-dimethylformamide (DMF), stir ultrasonically for 10 min, then put the homogeneous solution into a preheated oven, the reaction temperature is 150 °C, the reaction time is 15 h, then filter, wash with water, and dry in an 80 °C oven for 12 h to obtain MIL-53(Fe).

[0060] Comparative Example 2 Preparation of Cu-BTC

[0061] Take trimesic acid (H3BTC, 0.8107 g, 5 mmol) and mix it with 25 ml of dimethyl sulfoxide (DMSO), dissolve it ultrasonically, then cool the solution and slowly add Cu(NO3)2·3H2O (2.1744 g, 9 mmol), dissolve and stir ultrasonically for 30 min to obtain a blue transparent solution. Transfer the solution to a 50 ml reaction kettle and heat it at a constant temperature of 120 °C for 24 h to obtain Cu-BTC microcrystals.

[0062] Catalyst performance test

[0063] Take the catalyst materials prepared in Examples 1 to 15 and Comparative Examples 1 and 2, and test their catalytic performance for the oxidative degradation of tetracycline hydrochloride by hydrogen peroxide. The test conditions are: hydrogen peroxide concentration 0.5 μL / mL; catalyst input amount: 10 mg / L; tetracycline concentration 50 mg / L. The results are shown in Table 1.

[0064] Table 1 Performance comparison of the supported catalysts prepared in Examples 1-15 and Comparative Examples 1 and 2

[0065]

[0066]

Claims

1. A preparation method of a "defective" metal-organic framework catalyst by persulfate etching mutagenesis, characterized in that, The described preparation method includes: Put the metal-organic framework material and persulfate into a reaction vessel, evacuate and then introduce an inert gas, carry out chemical vapor deposition reaction at 120 - 180 °C for 6 - 12 h, wash the obtained solid product with pure water and ethanol, and dry it to obtain the "defective" metal-organic framework catalyst etched and mutagenized by persulfate; Wherein, The metal-organic framework material is selected from: MIL-53(Fe) or Cu-BTC; The mass ratio of the metal-organic framework material to persulfate is 1:

2.

2. The preparation method of the "defective" metal-organic framework catalyst by persulfate etching mutagenesis according to claim 1, characterized in that, The persulfate is selected from one or a mixture of two or more of potassium persulfate, sodium persulfate, and ammonium persulfate in any proportion.

3. The preparation method of the "defective" metal-organic framework catalyst by persulfate etching mutagenesis according to claim 1, characterized in that, The inert gas is selected as argon, and the gas flow rate is 50 - 80 cm / s.

4. The preparation method of the "defective" metal-organic framework catalyst by persulfate etching mutagenesis according to claim 1, characterized in that, The temperature of chemical vapor deposition is 150 °C and the time is 6 h.

5. The "defective" metal-organic framework catalyst etched and mutagenized by persulfate prepared by the preparation method according to any one of claims 1 - 4.

6. The application of the "defective" metal-organic framework catalyst etched and mutagenized by persulfate according to claim 5 in catalytic oxidation reactions.

7. The application according to claim 6, wherein The "defective" metal-organic framework catalyst etched and mutagenized by persulfate is used for catalytic oxidation degradation of tetracycline hydrochloride by hydrogen peroxide.

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