Three-dimensional cobalt metal organic complex and preparation method and application thereof

Abstract

The invention discloses a three-dimensional cobalt metal organic complex and a preparation method and application thereof, and belongs to the technical field of crystal materials. The three-dimensional cobalt metal organic complex with the chemical formula of [Co (DPDA) (4, 4 '-bpy)] n is prepared by selecting 2, 5-diketopiperazine-N, N'-diacetic acid, 4, 4 '-bipyridine and cobalt ions as raw materials. The three-dimensional network structure has a six-connection three-dimensional network structure of a dual-core [Co2 (COO) 2] structural unit, and the topological symbol is {312.424. 59}. Besides, the three-dimensional cobalt metal organic complex can quickly activate peroxymonosulfate to effectively degrade dyes, can degrade three dyes, namely methylene blue, malachite green and crystal violet, to 95.0% or above within 5 minutes, does not generate toxic byproducts in the degradation process, and has a relatively good reuse rate. In addition, the three-dimensional cobalt metal organic complex is mild in synthesis condition and simple in step, has excellent structural stability and good thermal stability, and has antiferromagnetism at high temperature.

Description

Technical Field

[0001] The invention belongs to the technical field of crystal materials, and specifically relates to a three-dimensional cobalt metal organic complex and a preparation method and application thereof. Background Art

[0002] Currently, the main methods for water pollution treatment include biological treatment, physical adsorption, chemical oxidation and photocatalytic degradation. Low dye removal efficiency and high operating costs are observed in most traditional methods. At the same time, toxic by-products are produced at the end of the conventional treatment process.

[0003] Metal-organic frameworks (MOFs) are new porous materials that are assembled through coordination bonds using metal ions or metal atom clusters as nodes or secondary structural units and multifunctional organic ligands as connectors. They have the characteristics of high porosity, high specific surface area, and adjustable structure. However, most of the publicly published MOFs for degrading dyes have the disadvantages of poor stability, slow speed, secondary pollution, and low recyclability, which hinder their application to a certain extent. Therefore, the design and synthesis of MOFs with stable structure and the ability to degrade a variety of dyes is of great significance in the treatment of dye wastewater and environmental protection. Summary of the invention

[0004] In view of the shortcomings of the above-mentioned prior art, the present invention provides a three-dimensional cobalt metal organic complex and its preparation method and application. The three-dimensional cobalt metal organic complex of the present invention can quickly activate peroxymonosulfate to generate free radicals, can quickly degrade organic dyes in less than 5 minutes, and the leaching rate of Co ions is very low, has good stability and repeatability, and can be used for practical applications.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A three-dimensional cobalt metal organic complex with the chemical formula [Co(DPDA)(4,4'-bpy)] n , DPDA 2- The ligand represents a divalent anion of 2,5-diketopiperazine-N,N'-diacetic acid that has lost two protons; the 4,4'-bpy ligand represents an electrically neutral 4,4'-bipyridine ligand; Co represents a positive divalent cobalt ion; and n represents a non-zero natural number.

[0007] As a preferred embodiment of the present invention, the crystal structure of the three-dimensional cobalt metal organic complex belongs to the monoclinic system, C2 space group; the unit cell parameters are: α=90°, β=100.177(3)°, γ=90°.

[0008] As a preferred embodiment of the present invention, the central Co(II) ion of the three-dimensional cobalt metal organic complex adopts a six-coordination mode, and is respectively composed of four O atoms from four different DPDA ligands, and the top position is occupied by two N atoms of 4,4'-bpy; the four O atoms in the complex are on the same plane, and the bond angle of N1A-Co2-N2 is 180°, forming a tetragonal bipyramidal structure; the bond lengths of Co-N and Co-O at the center of the Co(II) ion are respectively

[0009] As a preferred embodiment of the present invention, the cobalt metal organic complex is a three-dimensional network structure, which can be simplified as a six-connected topological structure of binuclear [Co2(COO)2] structural units, and the topological symbol is {3 12 .4 24 .5 9}.

[0010] The present invention also claims a method for preparing the three-dimensional cobalt metal organic complex, comprising the following steps: dissolving cobalt salt and 4,4'-bpy in a mixed solution of H2O and methanol to obtain solution A, dissolving H2DPDA crystals in a NaOH solution to obtain solution B, mixing solution A and solution B uniformly, and then performing a hydrothermal reaction to obtain a three-dimensional cobalt metal organic complex.

[0011] As a preferred embodiment of the present invention, the method for preparing H2DPDA crystals comprises the following steps: uniformly mixing iminodiacetic acid, phosphoric acid and water, performing a hydrothermal reaction, and cooling to room temperature to obtain H2DPDA crystals;

[0012] As a preferred embodiment of the present invention, the temperature of the hydrothermal reaction after the iminodiacetic acid, phosphoric acid and water are uniformly mixed is 170° C. and the time is 12 hours.

[0013] As a preferred embodiment of the present invention, the molar ratio of the cobalt salt, H2DPDA and 4,4'-bpy is 1:(0.5-1.5):(1-3).

[0014] As a preferred embodiment of the present invention, the volume ratio of H2O to methanol is (9-12):2.

[0015] As a preferred embodiment of the present invention, the molar ratio of H2DPDA to NaOH is 1:(1-2.2).

[0016] As a preferred embodiment of the present invention, the temperature of the hydrothermal reaction after the solution A and the solution B are mixed is 100° C. and the time is 72 hours.

[0017] As a preferred embodiment of the present invention, the cobalt source is one of cobalt acetate, cobalt sulfate and cobalt nitrate.

[0018] The present invention also claims the use of the three-dimensional cobalt metal organic complex, comprising the following steps:

[0019] The three-dimensional cobalt metal organic complex can effectively degrade three dyes, namely methylene blue (MB), malachite green (MG) and crystal violet (CV). The amount of the three-dimensional cobalt metal organic complex is 10 mg, the amount of peroxymonosulfate is 15 mg, the concentrations of the three dyes, namely methylene blue (MB), malachite green (MG) and crystal violet (CV) are all 40 mg / L, and they all have good degradation ability under a xenon lamp light source. The degradation ability of the three-dimensional cobalt metal organic complex on the three dyes, namely methylene blue (MB), malachite green (MG) and crystal violet (CV), was monitored by UV-vis. Experimental data showed that the degradation rate of methylene blue (MB) within 5 minutes can reach more than 99%, while the degradation rates of malachite green (MG) and crystal violet (CV) are more than 99% and more than 96%, respectively.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The three-dimensional cobalt metal organic complex of the present invention is prepared by using 2,5-diketopiperazine-N,N'-diacetic acid and 4,4'-bipyridine as dual ligands and Co as metal ion. Compared with ordinary metal organic framework materials, it has more active sites and structural stability, and the prepared three-dimensional cobalt metal organic complex has excellent degradation performance; it can effectively activate peroxymonosulfate to degrade three dyes, methylene blue (MB), malachite green (MG) and crystal violet (CV). Experiments show that the degradation rates of methylene blue (MB), malachite green (MG) and crystal violet (CV) within 5 minutes are 99.82%, 99.70% and 96.68%, respectively. In addition, the three-dimensional cobalt metal organic complex of the present invention has good stability and recyclability. The main structure framework can be kept from collapsing at 300°C. After 5 cycles, the catalyst can still achieve a degradation rate of more than 90%.

[0022] (2) The preparation method of the three-dimensional cobalt metal-organic complex of the present invention has mild conditions, simple steps, strong operability, low energy consumption, and high yield during synthesis. The metal-organic framework material has excellent economy and feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the crystal structure of the three-dimensional cobalt metal organic complex prepared in Example 1 of the present invention.

[0024] Figure 2 It is a crystal three-dimensional stacking structure diagram of the three-dimensional cobalt metal organic complex prepared in Example 1 of the present invention.

[0025] Figure 3 It is a topological diagram of the three-dimensional structure of the three-dimensional cobalt metal organic complex prepared in Example 1 of the present invention.

[0026] Figure 4 This is the infrared spectrum of the three-dimensional cobalt metal organic complex prepared in Example 1.

[0027] Figure 5 These are the experimental and simulated powder diffraction patterns of the three-dimensional cobalt metal organic complex prepared in Example 1.

[0028] Figure 6 It is a thermogravimetric curve of the three-dimensional cobalt metal organic complex prepared in Example 1.

[0029] Figure 7 This is a temperature-dependent magnetic susceptibility curve of the three-dimensional cobalt metal organic complex prepared in Example 1.

[0030] Figure 8 The three-dimensional cobalt metal organic complex prepared in Example 1 catalyzes potassium persulfate to degrade three dyes: methylene blue, malachite green and crystal violet.

[0031] Fig. 9 The degradation efficiency of methylene blue catalyzed by potassium persulfate at different pH values ​​for the three-dimensional cobalt metal organic complex prepared in Example 1 is shown.

[0032] Fig.10 This is the cyclic result of the three-dimensional cobalt metal organic complex prepared in Example 1 catalyzing the degradation of methylene blue by potassium persulfate.

[0033] Fig.11 This is the XRD diagram of the three-dimensional cobalt metal organic complex prepared in Example 1 before and after the catalytic degradation of methylene blue by potassium persulfate. DETAILED DESCRIPTION

[0034] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0035] Example 1

[0036] A method for preparing a three-dimensional cobalt metal organic complex comprises the following steps:

[0037] (1) 9.0 g of iminodiacetic acid, 6.9 ml of phosphoric acid and 540 ml of water were mixed evenly in polytetrafluoroethylene, reacted at a high temperature of 170° C. for 12 hours, and cooled to room temperature to obtain H2DPDA crystals.

[0038] (2) 0.4 mmol Co(NO3)2·6H2O and 0.4 mmol 4,4'-bpy were dissolved in 4 ml H2O and methanol mixed solution (volume ratio 9:2); 0.2 mmol H2DPDA crystals were dissolved in 2 ml 0.2 mol / L NaOH solution, the two mixed solutions were mixed evenly, and then transferred to polytetrafluoroethylene, crystallized at 100°C for 72 hours, and then at 5°C·h -1 The rate of cooling to room temperature is used to obtain a three-dimensional cobalt metal organic complex.

[0039] The study found that when the molar ratio of Co(NO3)2·6H2O, H2DPDA and 4,4'-bpy was 1:0.5:1, the resulting three-dimensional cobalt metal organic complex had the most complete crystallinity, the largest single crystal volume and relatively uniform crystal particles, and the yield of the three-dimensional cobalt metal organic complex was 78.62%.

[0040] Example 2

[0041] A method for preparing a three-dimensional cobalt metal organic complex comprises the following steps:

[0042] (1) 9.0 g of iminodiacetic acid, 6.9 ml of phosphoric acid and 540 ml of water were mixed evenly in polytetrafluoroethylene, reacted at a high temperature of 170° C. for 12 hours, and cooled to room temperature to obtain H2DPDA crystals.

[0043] (2) 0.4mmol Co(NO3)2·6H2O and 1.2mmol 4,4'-bpy were dissolved in 4ml H2O and methanol mixed solution (volume ratio of 9:2); 0.6mmol H2DPDA crystals were dissolved in 2ml 0.3mol / L NaOH solution, the two mixed solutions were mixed evenly, and then transferred to polytetrafluoroethylene, crystallized at 100℃ for 72 hours, and then at 5℃·h -1 The rate of cooling to room temperature is used to obtain a three-dimensional cobalt metal organic complex.

[0044] The study found that when the molar ratio of Co(NO3)2·6H2O, H2DPDA and 4,4'-bpy was 1:1.5:3, the resulting three-dimensional cobalt metal organic complex crystals had relatively complete crystallinity, the single crystal volume was medium and the crystal particles were relatively irregular, and the yield of the three-dimensional cobalt metal organic complex was 68.57%.

[0045] Example 3

[0046] A method for preparing a three-dimensional cobalt metal organic complex comprises the following steps:

[0047] (1) 9.0 g of iminodiacetic acid, 6.9 ml of phosphoric acid and 540 ml of water were mixed evenly in polytetrafluoroethylene, reacted at a high temperature of 170° C. for 12 hours, and cooled to room temperature to obtain H2DPDA crystals.

[0048] (2) 0.4mmol Co(NO3)2·6H2O and 0.4mmol 4,4'-bpy were dissolved in 4ml H2O and methanol mixed solution (volume ratio of 12:2); 0.4mmol H2DPDA crystals were dissolved in 2ml 0.44mol / L NaOH solution, the two mixed solutions were mixed evenly, and then transferred to polytetrafluoroethylene, crystallized at 100℃ for 72 hours, and then at 5℃·h -1 The rate of cooling to room temperature is used to obtain a three-dimensional cobalt metal organic complex.

[0049] The study found that when the molar ratio of Co(NO3)2·6H2O, H2DPDA and 4,4'-bpy is 1:1:1, the resulting three-dimensional cobalt metal organic complex crystals have relatively complete crystallinity, the volume of single crystals is small but the crystal particles are relatively uniform, and the yield of the three-dimensional cobalt metal organic complex is 65.91%.

[0050] Example 4

[0051] The only difference between the method for preparing the three-dimensional cobalt metal organic complex described in this example and that in Example 1 is that the Co(NO3)2·6H2O in step (2) is replaced by an equimolar amount of Co(OAc)2·4H2O.

[0052] Example 5

[0053] The only difference between the method for preparing the three-dimensional cobalt metal organic complex described in this example and that in Example 1 is that the Co(NO3)2·6H2O in step (2) is replaced by an equimolar amount of CoSO4·7H2O.

[0054] By comparing Example 1 with Examples 4-5, it can be seen that when the cobalt source is Co(NO3)2·6H2O, the obtained three-dimensional cobalt metal organic complex crystal has the most complete crystallinity, and the volume of a single crystal and the crystal particles are relatively uniform.

[0055] Effect Example 1

[0056] The single crystal X-ray intensity data were acquired with graphite monochromator equipped with Mo Kα radiation. The structure was collected on a Bruker SMARTAPEX II diffractometer at 296(2)K. The structure was solved and the space group was determined using the direct method using the ShelXS-97 structure solver (Sheldrick, 2008), and then refined using the full matrix least squares minimization method on F2 using the ShelXL-97 version (Sheldrick, 2008). All non-hydrogen atoms were anisotropically refined, and the positions of hydrogen atoms were obtained by geometric calculations and refined using the riding model. Some parameters for the crystal diffraction data collection and structure refinement of the three-dimensional cobalt metal organic complex prepared in Example 1 are shown in Table 1.

[0057] Table 1

[0058]

[0059]

[0060] The three-dimensional cobalt metal organic complexes prepared in Examples 1-5 have the same structure, such as Figure 1 The central Co(II) ion adopts a hexa-coordinated structure and is connected to four different DPDA 2- The four O atoms in the complex are almost in the same plane, and the bond angle of N1A-Co2-N2 is 180°, forming a tetrahedral bipyramidal structure. The bond lengths of Co-N and Co-O at the Co(II) center are in the range of and

[0061] like Figure 2 As shown, in the three-dimensional cobalt metal organic complex prepared in Examples 1-5 of the present invention, two adjacent Co(II) ions are separated by two DPDA 2- The terminal carboxyl groups of the ligands are bridged to form a [Co2(COO)2] binuclear structural unit. 2- The ligands are completely deprotonated and have a μ2-η 2 :η 2 The two-position bridging mode connects two adjacent [Co2(COO)2] binuclear structural units. At the same time, the 4,4'-bpy ligand adopts μ2-η 1 :η 1 The coordination mode connects the adjacent [Co2(COO)2] binuclear structural units into an infinitely extended one-dimensional chain. Therefore, each binuclear [Co2(COO)2] is infinitely extended into a three-dimensional network framework through six bridging ligands. Each [Co2(COO)2] binuclear cluster is regarded as a six-connected node, such as Figure 3The general structure can be simplified into a three-dimensional 6-connected topological network structure, and the topological symbol is {3 12 .4 24 .5 9}.

[0062] The three-dimensional cobalt-based metal organic complexes prepared in Examples 1-5 have the same structure, and only the relevant detection of the three-dimensional cobalt-based metal organic complex prepared in Example 1 is shown below. Figure 4 As shown, Example 1 at 3511cm -1 There is a broad and strong infrared peak at 2944cm -1 The weak absorption band at about 1651cm is due to the CH stretching vibration of aromatic groups. -1 The C=O symmetric and asymmetric stretching vibrations are shown at 1308 cm -1 The characteristic CN stretching vibration appears. The C=C stretching vibration of the aromatic ring skeleton is located at 1497cm -1 , and the absorption peaks of aromatic CH bonds are at 400 and 800 cm -1 The above shows that the complex of Example 1 has been successfully prepared. Figure 5 As shown, by comparing the XRD curve of Example 1 with the curve obtained by simulating crystal data, it can be seen that the complex prepared in Example 1 is a pure phase. Figure 6 As shown, the cobalt metal organic complex prepared in Example 1 begins to collapse in crystal structure after 300° C., and has good thermal stability.

[0063] Effect Example 2

[0064] Under an external DC magnetic field of 1000 Oe, the three-dimensional cobalt metal organic complex obtained in Example 1 was subjected to a temperature-dependent magnetic susceptibility test.

[0065] The temperature-dependent magnetization curves of the prepared three-dimensional cobalt-based metal organic complex are shown in Figure 7 As shown in Figure 2, it can be seen that the temperature-dependent magnetic susceptibility χ of the complex at 300K M T value is 3.00cm 3 ·K·mol -1 , which is lower than the 3.75 cm of two independent Co(II) atoms. 3 ·K·mol -1 , which may be due to the strong spin-orbit coupling in the octahedral environment. As the temperature decreases, χ M The T value slowly decreases and reaches 2.49cm at 32K 3 ·K·mol -1 . Then, χ M The T value suddenly increases, reaching a maximum of 3.84cm at 4K 3·K·mol -1 , χ M The sharp increase in T can be attributed to the interchain ferromagnetic interaction between adjacent cobalt ion centers, which drops to 2.51 cm at 2 K. 3 ·K·mol -1 , which is attributed to the antiferromagnetic interaction and spin-orbit coupling, indicating that the complex is antiferromagnetic at high temperatures.

[0066] Effect Example 3

[0067] Test sample: the three-dimensional cobalt metal organic complex prepared in Example 1, 2, 3, 4 or 5.

[0068] Test method: Weigh 10 mg of the test sample and add it to 50 ml of dye aqueous solution (40 mg / L), and stir it in the dark for 30 minutes to allow the complex surface to reach adsorption-desorption equilibrium, then add 15 mg of potassium persulfate, and introduce a 10W xenon lamp light source, the temperature is room temperature, and the pH is 7.

[0069] like Figure 8 As shown, the degradation rate of the three-dimensional cobalt metal organic complex obtained in Example 1 for methylene blue is as high as 99.82% within 5 minutes after the addition of potassium persulfate, the degradation rate for malachite green is as high as 99.70%, and the degradation rate for crystal violet is as high as 96.68%.

[0070] The three-dimensional cobalt metal organic complexes obtained in Examples 2 to 5 have the same structure as that in Example 1, and the effects in the degradation of methylene blue, malachite green and crystal violet dyes are similar to those in Example 1.

[0071] The results show that the three-dimensional cobalt-based metal organic complex of the present invention has a high degradation rate for three dyes and can degrade multiple dyes. The three-dimensional cobalt-based metal organic complex of the present invention is a highly efficient catalyst for degrading dyes.

[0072] Effect Example 4

[0073] Test sample: the three-dimensional cobalt metal organic complex prepared in Example 1, 2, 3, 4 or 5.

[0074] Test method: Weigh 10 mg of the test sample and add it to 50 ml of methylene blue aqueous solution (40 mg / L), and stir it in the dark for 30 minutes to allow the complex surface to reach adsorption-desorption equilibrium, then add 15 mg of potassium persulfate, and introduce a 10W xenon light source. The temperature is room temperature and the pH is 3, 5, 7, 9, and 11 respectively. The pH range of methylene blue dye degradation of the three-dimensional cobalt metal organic complex is tested. Fig. 9As shown, within the pH range of 3-11, the complex prepared in Example 1 exhibits a strong degradation ability in catalyzing potassium persulfate, which means that it can also be used in practice under the same environmental conditions.

[0075] The three-dimensional cobalt metal organic complexes obtained in Examples 2 to 5 have the same structure as that in Example 1, and the effects of degrading methylene blue dye at different pH values ​​are similar to those in Example 1.

[0076] Effect Example 5

[0077] Test sample: the three-dimensional cobalt metal organic complex prepared in Example 1, 2, 3, 4 or 5.

[0078] Test method: Weigh 10 mg of the test sample and add it to 50 ml of methylene blue aqueous solution (40 mg / L), and stir it in the dark for 30 minutes to allow the complex surface to reach adsorption-desorption equilibrium, then add 15 mg of potassium persulfate, and introduce a 10W xenon light source. The temperature is room temperature and pH 7, and the three-dimensional cobalt metal organic complex is tested for the reusability of methylene blue dye degradation. Fig.10 As shown, after the complex prepared in Example 1 catalyzes potassium persulfate for 5 cycles, the degradation efficiency of methylene blue is still maintained at more than 90%, indicating that the catalytic activity of the complex is stable and can be reused.

[0079] The three-dimensional cobalt metal organic complexes obtained in Examples 2 to 5 have the same structure as that in Example 1. In the recovery experiment of degrading methylene blue dye, the effect is similar to that in Example 1.

[0080] Effect Example 6

[0081] Whether three-dimensional cobalt-based metal organic complexes can leach cobalt ions in the degradation of dyes. Fig.11 As shown, from the XRD curves before and after the degradation of methylene blue dye in Example 1, it can be seen that since Co ions can quickly activate PMS to produce free radicals to degrade the dye, excessive overflow of Co ions will pollute the environment. Compared with the newly prepared complex, the experimental data obtained by Co-MOFs@methylene blue material has certain differences in peak intensity, but the main peaks still exist and the framework has not collapsed, indicating that Example 1 does not produce excessive toxic byproducts such as Co ions during the degradation process.

[0082] In summary, the three-dimensional cobalt-based metal organic complex of the present invention exhibits excellent performance in the field of dye degradation, and shows high degradation efficiency for the three dyes MB, MG, and CV. It is a highly efficient catalyst and is expected to be widely used in a variety of environments to remove organic pollutants.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A three-dimensional cobalt metal organic complex, characterized in that: The chemical formula is [Co(DPDA)(4,4'-bpy)] n , DPDA 2- Ligand represents a divalent anion of 2,5-diketopiperazine-N,N'-diacetic acid that has lost two protons, 4,4'-bpy Ligand represents an electrically neutral 4,4'-bipyridine ligand, Co represents a positive divalent cobalt ion, and n represents a non-zero natural number.

2. The three-dimensional cobalt metal organic complex according to claim 1, characterized in that: The crystal structure of the three-dimensional cobalt metal organic complex belongs to the monoclinic system and the C2 space group; the unit cell parameters are: α=90°, β=100.177(3)°, γ=90°.

3. The cobalt metal organic complex according to claim 1, characterized in that The cobalt metal organic complex is a three-dimensional network structure, a six-connected topological structure of binuclear [Co2(COO)2] structural units, and the topological symbol is {3 12 .4 24 .5 9 }.

4. The method for preparing the three-dimensional cobalt metal organic complex according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: dissolving a cobalt source and 4,4'-bpy in a mixed solution of H2O and methanol to obtain a solution A, dissolving H2DPDA crystals in a NaOH solution to obtain a solution B, mixing the solution A and the solution B evenly, and then performing a hydrothermal reaction to obtain a three-dimensional cobalt metal organic complex.

5. The method for preparing a three-dimensional cobalt metal organic complex according to claim 4, characterized in that: The volume ratio of H2O to methanol is (9-12):

2.

6. The method for preparing a three-dimensional cobalt metal organic complex according to claim 4, characterized in that: The molar ratio of H2DPDA to NaOH is 1:(1-2.2).

7. The method for preparing a three-dimensional cobalt metal organic complex according to claim 4, characterized in that: The molar ratio of the cobalt source, H2DPDA and 4,4'-bpy is 1:(0.5-1.5):(1-3).

8. The method for preparing a three-dimensional cobalt metal organic complex according to claim 4, characterized in that: The temperature of the hydrothermal reaction is 100° C. and the time is 72 hours.

9. The method for preparing a three-dimensional cobalt metal organic complex according to claim 4, characterized in that: The cobalt source is one of cobalt acetate, cobalt sulfate and cobalt nitrate.

10. Use of the three-dimensional cobalt metal organic complex according to any one of claims 1 to 3 in activating peroxymonosulfate to catalyze the degradation of organic pollutants.

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