Preparation method and application of interlayer confinement Co monatomic catalyst

Abstract

The invention discloses a preparation method and application of an interlayer confinement Co monatomic catalyst, and the method comprises the following steps: firstly, carrying out cobalt monatomic embedding in the center of a porphyrin ring to obtain a porphyrin ligand embedded with Co monatomic, and then carrying out one-step organic solvothermal synthesis to obtain the interlayer confinement Co monatomic catalyst. The preparation method comprises the following steps: combining cluster metal ions with a porphyrin ligand embedded with Co monatomic to prepare a porphyrin-based metal organic framework CoSAs-PMOF, namely the Co monatomic catalyst of interlayer confinement. The Co monatomic catalyst in the interlayer confinement is used for activating hydrogen peroxide to generate active oxygen free radicals dominated by singlet oxygen, and then ciprofloxacin is degraded. The invention provides a novel method for degrading ciprofloxacin.

Description

Technical Field

[0001] The present invention relates to the field of advanced oxidation, and in particular to a preparation method and application of an interlayer confined Co single atom catalyst. Background Art

[0002] The uncontrolled use of antibiotics has led to their continuous enrichment in the environment, which has become a global challenge threatening human health and ecological security. Therefore, people strongly hope to develop cost-effective and efficient water pollution evolution technologies. In this field, multiphase Fenton-like technologies can achieve effective degradation of pollutants in water bodies by generating a series of free radical and non-free radical active substances. Among them, singlet oxygen ( 1 O 2 ) and other non-radical active species with strong oxidizing properties, long lifetimes, and excellent resistance to environmental perturbations have become a hot topic and frontier in research. Among the catalysts mediating non-radical Fenton-like reactions, single-atom catalysts (SACs) can significantly enhance the degradation kinetics of pollutants compared with their counterparts due to their unique electronic properties. However, existing SACs-mediated Fenton-like processes are still limited by the restricted accessibility between reactants and single-atom sites and the short diffusion range of active species.

[0003] Recent studies have shown that confining single atoms in nanometer-confined spaces can improve the accessibility of single-atom sites and reactants to reactants, leading to an order of magnitude increase in the efficiency of Fenton-like systems. However, the random distribution of single-atom sites in nanometer-confined environments has long led to the neglect of the correlation between single-atom sites. Therefore, asymmetric oxidant molecules such as peroxymonosulfate (PMS) are always used preferentially, while symmetric oxidant molecules such as H 2 O 2 Few research cases have been reported. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method and application of an interlayer confined Co single atom catalyst, which is based on a two-dimensional porphyrin metal material and adopts a surfactant-assisted bottom-up method to prepare a metal organic framework material CoSAs-PMOF with interlayer confinement, which can activate hydrogen peroxide to produce active oxygen free radicals dominated by singlet oxygen for degrading CIP (ciprofloxacin) in water.

[0005] In one aspect of the present invention, the present invention proposes a method for preparing an interlayer confined Co single atom catalyst. According to an embodiment of the present invention, the method comprises the following steps: first, a cobalt single atom is embedded in the center of the porphyrin ring to obtain a porphyrin ligand embedded with a Co single atom, and then a one-step organic solvent thermal synthesis method is used to combine the cluster metal ions with the porphyrin ligand embedded with a Co single atom to prepare a porphyrin-based metal organic framework CoSAs-PMOF, which is the interlayer confined Co single atom catalyst.

[0006] In addition, the method for preparing an interlayer confined Co single atom catalyst according to the above embodiment of the present invention may also have the following additional technical features:

[0007] In some embodiments of the present invention, embedding a single cobalt atom in the center of the porphyrin ring specifically comprises the following steps:

[0008] (1) Under a nitrogen atmosphere, methyl p-formylbenzoate is dissolved in propionic acid, and then newly purified pyrrole is added dropwise, the solution is refluxed at 140-160° C. for 12-24 hours, and after cooling, purple crystalline TCPPOME is obtained by suction filtration;

[0009] (2) TPPCOOME and CoCl 2 Reflux in N,N-dimethylformamide solution at 140-160°C for 8-16 hours. After cooling, add H 2 O, and then filtered through an organic filter membrane several times, the collected filter cake was immediately dissolved with chloroform, and then the resulting solution was filtered again, and the filtrate was washed with hydrochloric acid and H 2 O was extracted several times and dried to obtain Co-TCPPOME;

[0010] (3) Cu-TCPPOME was stirred in a tetrahydrofuran-methanol solvent, and a KOH aqueous solution was added, and refluxed at 80-100°C for 10-16 hours. Tetrahydrofuran and methanol were evaporated during cooling, and water was added to the remaining mixture. HCl was then added dropwise to the solution until no more precipitate was formed. The green precipitate was collected by filtration, washed with water and dried in vacuo to obtain purple crystalline CoSAs-TCPP.

[0011] In some embodiments of the present invention, in step (1), the mass ratio of methyl paraformylbenzoate to pyrrole is (2-3):1; in step (2), the mass ratio of TPPCOOME to CoCl 2 The mass ratio of Cu-TCPPOME and KOH is 1:(3-4).

[0012] In some embodiments of the present invention, the raw materials of the one-step organic solvent thermal synthesis method include copper nitrate trihydrate, CoSAs-TCPP, trifluoroacetic acid, anhydrous ethanol, polyvinyl pyrrolidone and N,N-dimethylformamide.

[0013] In some embodiments of the present invention, the one-step organic solvent thermal synthesis specifically comprises the following steps:

[0014] First, Cu(NO 3 ) 2 ·3H 2 O, formic acid, and PVP (polyvinyl pyrrolidone) are dissolved in N, N-dimethylformamide-anhydrous ethanol solution to obtain a mixed solution. Under stirring, CoSAs-TCPP is dissolved in a mixed solvent of N, N-dimethylformamide and ethanol, mixed with the mixed solution and added into a 20 ml polytetrafluoroethylene liner, and reacted in an oven at 80-90° C. for 12-24 hours. The solution obtained after the reaction is filtered, washed, and dried to obtain the porphyrin-based metal organic framework CoSAs-PMOF.

[0015] In some embodiments of the present invention, the Cu(NO 3 ) 2 ·3H 2 The mass ratio of O, formic acid, PVP, and CoSAs-TCPP is (2-3):(40-50):10:(4-5).

[0016] In another aspect of the present invention, the present invention provides an interlayer confined Co single atom catalyst prepared according to the preparation method of the interlayer confined Co single atom catalyst.

[0017] In another aspect of the present invention, a method for degrading ciprofloxacin is provided. According to an embodiment of the present invention, the interlayer confined Co single atom catalyst is used to activate hydrogen peroxide to generate active oxygen free radicals dominated by singlet oxygen, and then ciprofloxacin is degraded.

[0018] In addition, the ciprofloxacin degradation method according to the above embodiment of the present invention may also have the following additional technical features:

[0019] In some embodiments of the present invention, the method comprises the following steps: dispersing CoSAs-PMOF in a ciprofloxacin solution, and then adding a hydrogen peroxide solution.

[0020] In some embodiments of the present invention, the mass ratio of the CoSAs-PMOF, ciprofloxacin, and hydrogen peroxide is (4-5):(0.5-1):(15-20).

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) The present invention is based on two-dimensional porphyrin metal materials, and adopts a surfactant-assisted bottom-up method to prepare a metal organic framework material CoSAs-PMOF with interlayer confinement. Specifically, the single atom Co is precisely embedded with the help of a standard porphyrin template substrate, and on this basis, the coordination mode of the porphyrin ligand and the divalent copper ion is utilized, and the auxiliary effect of surfactants and regulators is added to successfully synthesize the two-dimensional porphyrin metal organic framework doped with Co single atoms, wherein the two-dimensional porphyrin metal organic framework is arranged in a stacked manner, and there is a nano-confined space between the layers, and the Co single atoms in the layer are in the confined environment. Compared with the existing methods for constructing nanoconfined spaces, on the one hand, the method proposed in this invention has the advantages of simple operation and precise construction, and does not involve complex, energy-consuming multi-step pyrolysis steps and the use of strong acid reagents; in addition, thanks to the structural advantages of the two-dimensional porphyrin metal-organic framework, the Co single atoms in the nanoconfined environment correspond one to one in the z-axis direction, and can exert a synergistic effect between single atoms, thereby selectively activating hydrogen peroxide to produce singlet oxygen, which is significantly different from existing methods.

[0023] 2) The present invention provides a new method for degrading CIP in water by activating hydrogen peroxide with a confined Co single-atom catalyst to produce active oxygen free radicals dominated by singlet oxygen. 2 O 2 In the system, the highest degradation kinetic rate constant can reach 0.145min -1 , this value is TCPP-Cu(0.014min -1 ) is 10 times that of CoSAs-TCPP (0.005min -1 ). The characterization results of UV-Vis, FTIR, XRD, and XAS respectively confirmed the successful embedding of the cobalt single atom in the center of the metal porphyrin ring and the formation of the porphyrin-based metal organic framework. In addition, the quenching results showed that non-radical singlet oxygen played a dominant role in the degradation experiment. This method provides ideas for nano-confinement strategies to improve the performance of single-atom Fenton-like catalysts.

[0024] 3) The two-dimensional porphyrin metal organic framework of the present invention is arranged in a stacked manner, with a confined space of 0.9 nm between layers, and the Co single atoms in the layer are in the confined environment and correspond to each other in the z-axis direction. This unique arrangement is reflected in the synergistic effect between the Co single atoms in the structure, and finally hydrogen peroxide is selectively converted into singlet oxygen, achieving efficient removal of pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1The UV-Vis spectra (UV-Vis) of CoSAs-TCPP prepared in Example 1 of the present invention and TCPP prepared in Comparative Example 2;

[0026] Figure 2 Fourier transform infrared spectra (FTIR) of CoSAs-PMOF and CoSAs-TCPP prepared in Example 1 of the present invention and TCPP-Cu prepared in Comparative Example 2;

[0027] Figure 3 This is an X-ray diffraction (XRD) characterization diagram of CoSAs-PMOF prepared in Example 1 of the present invention;

[0028] Figure 4 This is an X-ray absorption spectrum (XAS) characterization diagram of the CoSAs-PMOF prepared in Example 1 of the present invention;

[0029] Figure 5 As an application example of the present invention, CoSAs-TCPP, TCPP-Cu and CoSAs-PMOF are used to activate H 2 O 2 The degradation amount-time diagram of CIP in aqueous solution catalytically degraded under the system;

[0030] Figure 6 As an application example of the present invention, CoSAs-TCPP, TCPP-Cu and CoSAs-PMOF are used to activate H 2 O 2 The rate constant fitting diagram of catalytic degradation of CIP in aqueous solution under the system;

[0031] Figure 7 The present invention uses different active species quenchers to quench CoSAs-PMOF / H 2 O 2 System experiment;

[0032] Figure 8 The application examples of the present invention are CoSAs-PMOF / H under different quenching agents. 2 O 2 Kinetic rate constant diagram of the system removing CIP;

[0033] Fig. 9 A reproducible characterization diagram of CoSAs-PMOF used as an example of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Example 1

[0036] A method for preparing an interlayer confined Co single atom catalyst comprises the following steps:

[0037] (1) Under nitrogen atmosphere, 6.9 g of methyl paraformylbenzoate was dissolved in 100 mL of propionic acid in a 500 mL three-necked flask, and then the newly purified pyrrole was added dropwise. The solution was refluxed at 150° C. for 18 hours. When the system was cooled, purple crystals of tetrakis(4-ester phenyl)porphine (TCPPOME) were obtained by suction filtration;

[0038] (2) 450 mg of ester-terminated porphyrin and 0.98 g of CoCl 2 The solution in 60 mL of N,N-dimethylformamide (DMF) was refluxed at 160 °C for 10 hours. After cooling, 150 mL of H 2 The above solution was filtered through a 0.45um organic filter membrane several times, the collected filter cake was immediately dissolved with 100ml of chloroform, and then the resulting solution was filtered again. The resulting filtrate was washed with 1M hydrochloric acid and H 2 O extraction three times and drying to obtain Co single atom doped tetrakis(4-ester phenyl)porphine (Co-TCPPOME);

[0039] (3) 480 mg of Co single atom doped ester-terminated porphyrin was stirred in 50 ml of a 1:1 (tetrahydrofuran-methanol) solvent. After that, 1.8 g of KOH in 20 mL of water solution was added. The mixture was refluxed at 85 °C for 12 hours. Tetrahydrofuran and methanol were evaporated during cooling. 100 mL of water was added to the remaining mixture, and then 1 M HCl was added dropwise to the solution until no precipitate was formed. The green precipitate was collected by filtration, washed with water and dried in vacuo. Finally, purple crystalline Co single atom doped tetrakis(4-carboxyphenyl)porphine (CoSAs-TCPP) was obtained;

[0040] (4) 2.4 mg Cu(NO 3 ) 2 ·3H 2O, 40 μL formic acid and 10 mg PVP were dissolved in 12 ml DMF-EtOH solution at a volume ratio of 3:1. Then, 4.4 mg CoSAs-TCPP was dissolved in a mixed solvent of 3 mL DMF and 1 mL ethanol under stirring and added to a 20 ml polytetrafluoroethylene liner together with the above mixed solution, and reacted in an oven at 85 °C for 16 h; a Co single atom-doped two-dimensional porphyrin metal organic framework dispersion was obtained.

[0041] (5) Using a 0.22 um PVDF filter membrane, the obtained dispersion was first filtered under a negative pressure of -0.1 MPa to obtain a CoSAs-PMOF filter cake, and then washed with ethanol 6 times under this pressure to remove the reactants that did not participate in the reaction. The amount of ethanol used each time was 50 mL. Finally, the washed filter cake material was naturally dried to obtain a Co single atom-doped two-dimensional porphyrin metal organic framework (CoSAs-PMOF).

[0042] Comparative Example 1

[0043] The preparation method of TCPP comprises the following steps:

[0044] 0.8 g of TCPPOME prepared in step (1) of Example 1 was stirred in 50 ml of a (THF:MeOH) solvent with a volume ratio of 1:1. Afterwards, 25 ml of an aqueous solution of 3.0 g of KOH was added. The mixture was refluxed at 100° C. for 12 hours. THF and MeOH were evaporated during the cooling process. 100 mL of water was added to the remaining mixture, and then 1 M HCl was added dropwise to the solution until no more precipitate was formed. The green precipitate was collected by filtration, washed with water and dried in vacuo. Finally, purple crystalline tetrakis(4-carboxyphenyl)porphine (TCPP) was obtained.

[0045] Comparative Example 2

[0046] The preparation method of TCPP-Cu comprises the following steps:

[0047] 2.4 mg Cu(NO 3 ) 2 ·3H 2 O, 40 μL formic acid and 10 mg PVP were dissolved in 12 ml DMF-EtOH solution at a volume ratio of 3:1. Then, 4.4 mg CoSAs-TCPP was dissolved in a mixed solvent of 3 mL DMF and 1 mL ethanol under stirring and added to a 20 ml polytetrafluoroethylene liner together with the above mixed solution, and reacted in an oven at 85 °C for 16 h; a Co single atom-doped two-dimensional porphyrin metal organic framework dispersion (TCPP-Cu) was obtained.

[0048] The CoSAs-TCPP obtained in Example 1 and the TCPP obtained in Comparative Example 1 were subjected to UV-Vis spectroscopy (UV-Vis) analysis. Figure 1 UV-visible spectroscopy was used to confirm the local environment of the porphyrin in the PMOF. Specifically, the number of Q bands decreased from four in TCPP to one in CoSAs-TCPP, indicating that metallic cobalt was successfully fixed in the porphyrin core.

[0049] The CoSAs-PMOF and CoSAs-TCPP prepared in Example 1 and TCPP-Cu prepared in Comparative Example 2 were characterized by Fourier transform infrared spectroscopy (FTIR). Figure 2 As shown, 1240cm -1 and 1678cm -1 The strong peak at 1420 cm-1 can be attributed to the stretching vibrations of COH and C=O bonds of the carboxyl group of TCPP ligand. However, these peaks become less prominent when the precursor is attached to MOF, while the peak at 1420 cm-1 is -1 and 1620cm -1 A new absorption peak was observed at , which corresponds to the Cu paddle wheel (Cu 2 (COO) 4 ) of the CuO bonds. These FTIR features indicate that when forming CoSAs-PMOF, CoSAs-TCPP is 2+ The metal nodes were successfully connected. The characteristic peaks of the XRD spectrum of CoSAs-PMOF are located at 7.6°, 8.9°, 19.46°, 21.4°, 23° and 30.5°, which is very consistent with the 2D-MOF structure. In addition, the X-ray diffraction (XRD) characterization of CoSAs-MOF is as follows Figure 3 As shown. The characteristic peaks of the XRD pattern of CoSAs-PMOF are located at 7.6°, 8.9°, 19.46°, 21.4°, 23° and 30.5°, which is very consistent with the 2D-MOF structure. In order to clarify the atomic configuration of cobalt species in CoSAS-PMOF, the extended X-ray absorption fine structure (EXAFS) spectrum was analyzed by Fourier transform (FT) k3 weighted χ(k) function (FT-EXAFS). Figure 4 As shown, in the R space diagram, ≈ The significant peak of , corresponds to the Co-N scattering path of the first shell. It is worth noting that No metallic Co-Co bond was observed at No Co-O peak is observed at , which indicates the atomically dispersed Co sites in the CoSAS-PMOF catalyst.

[0050] Application Example 1

[0051] The degradation method of ciprofloxacin comprises the following steps:

[0052] (1) Prepare a simulated CIP wastewater solution with a concentration of 25 mg / L: First weigh 25 mg of CIP powder and dissolve it in 950 mL of water, then adjust the pH value of the original solution to 7.0 with 1 mol / L hydrochloric acid solution and 1 mol / L sodium hydroxide solution, and finally quantify it in a volumetric flask to 1 L. The concentration of ciprofloxacin (CIP) was analyzed and measured by high performance liquid chromatography (HPLC, Agilent). The specific method is to take 200 μL of the supernatant, add it to a high performance liquid phase vial, and then put it into a sample tray. The mobile phase eluent consists of 0.3% formic acid and acetonitrile, and the flow rate is 1 mL / min.

[0053] (2) 4 mg of CoSAs-PMOF and CoSAs-TCPP prepared in Example 1 and 4 mg of TCPP-Cu prepared in Comparative Example 2 were added to 50 mL of a simulated CIP wastewater solution with a concentration of 25 mg / L, and 50 uL of hydrogen peroxide (30% mass concentration of the original solution) was added.

[0054] At a certain time interval, 2 mL of the reaction solution was taken and the catalyst was filtered through a 0.22 μm PTFE filter to obtain the supernatant. The CIP concentration in the solution was detected by high performance liquid chromatography. The results were expressed as peak area. The above operation was repeated twice. The initial peak area of ​​the simulated CIP wastewater solution was recorded as C 0 The peak area at the corresponding time is recorded as C t , with C t / C 0 As the ordinate and t as the abscissa, a degradation efficiency diagram is drawn. Then the first seven points in the diagram are selected and the degradation rate-time (C t / C 0 -t) and the steepest part of the degradation curve is processed to obtain the maximum degradation rate constant K of the material.

[0055] Figure 5-6 CoSAs-TCPP, TCPP-Cu and CoSAs-PMOF were used to activate H 2 O 2 The degradation rate of CIP in aqueous solution under catalytic degradation system-time (C t / C 0 -t) and degradation rate constant linear fitting diagram, such as Figure 5 It is shown in that CoSAs-PMOF exhibits a higher CIP degradation rate compared with TCPP-Cu and CoSAs-TCPP; Figure 6 The degradation rate constants in the figure also show that CoSAs-PMOF has the highest CIP degradation rate constant, which is about 0.145min -1, which are 10.4 times and 29 times of those of TCPP-Cu and CoSAs-TCPP, respectively. The above results indicate that CoSAs-PMOF can efficiently activate hydrogen peroxide to degrade CIP.

[0056] By activating H in step (2) of the ciprofloxacin degradation method, CoSAs-PMOF 2 O 2 Tert-butyl alcohol (TBA, 2.39 mL), p-benzoquinone (p-BQ, 27.025 mg) and furfuryl alcohol (FFA, 2.16 mL) were added to the CIP degradation system as hydroxyl radicals (·OH), superoxide radicals (·O 2 ) and singlet oxygen 1 O 2 scavengers to identify the types of reactive oxygen species.

[0057] A blank control experiment was set up: 4 mg of the CoSAs-PMOF prepared in Example 1 was added to 50 mL of a simulated CIP wastewater solution with a concentration of 25 mg / L, and 50 uL of hydrogen peroxide (30% mass concentration of the original solution) was added.

[0058] like Figure 7 As shown in Figure 2, after tert-butyl alcohol (TBA) and p-benzoquinone (P-BQ) were introduced into the reaction system, the inhibition effect on CIP degradation efficiency was only 9.018% and 28.397%, respectively, which indicates that OH and ·O 2 However, FFA showed a significant inhibition rate (73.004%) on the degradation of CIP. Figure 8 The inhibition degradation rate constant in the figure also shows that the rate constant dropped to the minimum of 0.003min when FFA was added. -1 , which shows that 1 O 2 is involved in the activation of H 2 O 2 The main dominant species in the process.

[0059] The repeatability of the prepared material CoSAs-PMOF was tested, and the results are as follows Fig. 9 As shown, after 5 consecutive degradation tests, the degradation efficiency of the material can still be maintained above 75%.

[0060] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A method for preparing an interlayer confined Co single atom catalyst, characterized in that: The following steps are involved: First, a single cobalt atom is embedded in the center of the porphyrin ring to obtain a porphyrin ligand embedded with a single Co atom. Then, a one-step organic solvent thermal synthesis method is used to combine the clustered metal ions with the porphyrin ligand embedded with a single Co atom to prepare a porphyrin-based metal organic framework CoSAs-PMOF, which is the interlayer confined Co single atom catalyst.

2. The method for preparing an interlayer confined Co single atom catalyst according to claim 1, characterized in that: The embedding of a single cobalt atom in the center of the porphyrin ring specifically comprises the following steps: (1) Under a nitrogen atmosphere, methyl paraformylbenzoate is dissolved in propionic acid, and then newly purified pyrrole is added dropwise, the solution is refluxed at 140° C. to 160° C. for 12 to 24 hours, and after cooling, purple crystalline TCPPOME is obtained by suction filtration; (2) reflux TPPCOOME and CoCl2 in a solution of N,N-dimethylformamide at 140-160°C for 6-12h, and after cooling, add H2O to the above solution, and then filter it through an organic filter membrane for several times, and immediately dissolve the collected filter cake with chloroform, and then filter the resulting solution again, and extract the resulting filtrate with hydrochloric acid and H2O for multiple times, and dry it to obtain Co-TCPPOME; (3) Cu-TCPPOME was stirred in a tetrahydrofuran-methanol solvent, and a KOH aqueous solution was added, and refluxed at 80-100°C for 10-16 hours. Tetrahydrofuran and methanol were evaporated during cooling, and water was added to the remaining mixture. HCl was then added dropwise to the solution until no more precipitate was formed. The green precipitate was collected by filtration, washed with water and dried in vacuo to obtain purple crystalline CoSAs-TCPP.

3. The method for preparing an interlayer confined Co single atom catalyst according to claim 2, characterized in that: In step (1), the mass ratio of methyl p-formylbenzoate to pyrrole is (2-3):1; In step (2), the mass ratio of TPPCOOME to CoCl2 is 1:(2-2.5), and the pore size of the organic filter membrane is 0.4-0.5 um; In step (3), the mass ratio of Cu-TCPPOME to KOH is 1:(3-4).

4. The method for preparing an interlayer confined Co single atom catalyst according to claim 1, characterized in that: The raw materials of the one-step organic solvent thermal synthesis method include copper nitrate trihydrate, CoSAs-TCPP, trifluoroacetic acid, anhydrous ethanol, polyvinyl pyrrolidone and N,N-dimethylformamide.

5. The method for preparing an interlayer confined Co single atom catalyst according to claim 4, characterized in that: The one-step organic solvent thermal synthesis specifically comprises the following steps: First, Cu(NO3)2·3H2O, formic acid, and polyvinylpyrrolidone are dissolved in a mixed solvent of N,N-dimethylformamide-anhydrous ethanol to obtain a mixed solution. CoSAs-TCPP is dissolved in a mixed solvent of N,N-dimethylformamide and ethanol under stirring, and then mixed with the mixed solution and added to a polytetrafluoroethylene liner. The mixture is reacted in an oven at 80-90°C for 12-24h. The solution obtained after the reaction is filtered, washed, and dried to obtain a porphyrin-based metal organic framework CoSAs-PMOF.

6. The method for preparing an interlayer confined Co single atom catalyst according to claim 5, characterized in that: The mass ratio of Cu(NO3)2·3H2O, formic acid, PVP and CoSAs-TCPP is (2-3):(40-50):10:(4-5).

7. An interlayer confined Co single atom catalyst prepared according to the preparation method of an interlayer confined Co single atom catalyst according to any one of claims 1 to 6.

8. A method for degrading ciprofloxacin, characterized in that: The interlayer confined Co single atom catalyst described in claim 7 is used to activate hydrogen peroxide to produce active oxygen free radicals dominated by singlet oxygen, and then degrade ciprofloxacin.

9. A method for degrading ciprofloxacin according to claim 8, characterized in that: The following steps are involved: CoSAs-PMOF was dispersed in ciprofloxacin solution, and then hydrogen peroxide solution was added.

10. A method for degrading ciprofloxacin according to claim 9, characterized in that: The mass ratio of the CoSAs-PMOF, ciprofloxacin and hydrogen peroxide is (4-5):(0.5-1):(15-20).

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