Preparation method and application of interlayer confined co monatomic catalyst

Abstract

The application discloses a preparation method and application of an interlayer limited Co single-atom catalyst, and the method comprises the following steps: firstly, embedding a cobalt single atom at the center of a porphyrin ring to obtain a porphyrin ligand embedded with the cobalt single atom; and then, combining a cluster metal ion with the porphyrin ligand embedded with the cobalt single atom by using a one-step organic solvent thermal synthesis method to prepare a porphyrin-based metal organic framework CoSAs-PMOF, namely the interlayer limited Co single-atom catalyst. The interlayer limited Co single-atom catalyst is used for activating hydrogen peroxide to generate active oxygen free radicals dominated by singlet oxygen, and then degrading ciprofloxacin. The application provides a new method for degrading ciprofloxacin.

Description

Technical Field

[0001] This invention relates to the field of advanced oxidation, specifically to a method for preparing a Co single-atom catalyst confined in the interlayer and its application. Background Technology

[0002] The unchecked use of antibiotics has led to their continuous accumulation in the environment, becoming a global challenge threatening human health and ecological security. Therefore, there is a strong desire to develop cost-effective and efficient water pollution evolution technologies. In this field, multiphase Fenton-like technologies can achieve the effective degradation of pollutants in water bodies by generating a series of free radical and non-free radical reactive substances. Among them, singlet oxygen (… 1 Non-radical reactive species such as O2 (O2), which possess strong oxidizing power, long lifetime, and excellent resistance to environmental disturbances, have become a research hotspot and frontier. Among catalysts mediating non-radical Fenton-like reactions, single-atom catalysts (SACs) can significantly enhance the degradation kinetics of pollutants compared to their counterparts due to their unique electronic properties. However, existing SAC-mediated Fenton-like processes are still limited by the restricted accessibility between reactants and single-atom sites, as well as the short diffusion range of the active material.

[0003] Recent studies have shown that confining single atoms in nanoscale 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 nanoscale confined environments has long resulted in the neglect of correlations between single-atom sites. Therefore, asymmetric oxidizing agents such as peroxymonosulfate (PMS) are always preferentially used, while research on symmetric oxidizing agents such as H₂O₂ is rarely reported. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a Co single-atom catalyst with interlayer confinement and its application. Based on two-dimensional porphyrin metal materials, a bottom-up method with surfactant assistance is used to prepare a metal-organic framework material CoSAs-PMOF with interlayer confinement. It can activate hydrogen peroxide to generate reactive oxygen free radicals dominated by singlet oxygen for the degradation of CIP (ciprofloxacin) in water.

[0005] In one aspect of the present invention, a method for preparing a Co single-atom catalyst with interlayer confinement is provided. According to an embodiment of the present invention, the method includes the following steps: firstly, a cobalt single atom is intercalated into the center of a porphyrin ring to obtain a porphyrin ligand with an intercalated Co single atom; then, a porphyrin-based metal-organic framework CoSAs-PMOF is prepared by combining a cluster metal ion with the porphyrin ligand with the intercalated Co single atom using a one-step organic solvothermal synthesis method, which is the interlayer confinement Co single-atom catalyst.

[0006] In addition, the method for preparing the interlayer limited Co monatomic catalyst according to the above-mentioned embodiment of the present application can further have the following additional technical features.

[0007] In some embodiments of the present application, the step of embedding a cobalt monatomic atom at the center of the porphyrin ring specifically comprises the following steps:

[0008] (1) Dissolve methyl p-formylbenzoate in propionic acid under a nitrogen atmosphere, then add dropwise newly purified pyrrole, reflux the solution at 140-160°C for 12-24 hours, after cooling, obtain purple crystals TCPPOME by suction filtration;

[0009] (2) Reflux TPCCOOME and CoCl2 in a solution of N,N-dimethylformamide at 140-160°C for 8-16 hours, after cooling, add H2O to the above-mentioned solution, then filter the solution several times through an organic filter membrane, immediately dissolve the collected filter cake with chloroform, then filter the obtained solution again, dry the obtained filtrate by extracting with hydrochloric acid and H2O several times, to obtain Co-TCPPOME;

[0010] (3) Stir Cu-TCPPOME in tetrahydrofuran-methanol solvent, add aqueous KOH solution, reflux at 80-100°C for 10-16 hours, evaporate tetrahydrofuran and methanol during the cooling process, add water to the remaining mixture, then add dropwise HCl solution into the solution until no more precipitate is formed, collect the green precipitate by filtration, wash with water and dry under vacuum, finally obtain purple crystals CoSAs-TCPP.

[0011] In some embodiments of the present application, in step (1), the mass ratio of methyl p-formylbenzoate and pyrrole is (2-3):1; in step (2), the mass ratio of TPCCOOME and 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 and KOH is 1:(3-4).

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

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

[0014] Cu(NO3)2.3H2O, formic acid, PVP (polyvinylpyrrolidone) are dissolved in a N, N-dimethylformamide-absolute ethanol solution 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 then added into a 20 ml polytetrafluoroethylene liner, and then reacted in an 80-90℃ oven for 12-24 h, and then the obtained solution after reaction is filtered, washed, and dried to obtain a porphyrin metal organic framework CoSAs-PMOF.

[0015] In some embodiments of the present application, the mass ratio of Cu(NO3)2.3H2O, formic acid, PVP, and CoSAs-TCPP is (2-3):(40-50):10:(4-5).

[0016] In another aspect of the present application, the present application provides an interlayer confined Co monatomic catalyst prepared by the preparation method of the interlayer confined Co monatomic catalyst.

[0017] In another aspect of the present application, the present application provides a degradation method of ciprofloxacin. According to an embodiment of the present application, the interlayer confined Co monatomic 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 degradation method of ciprofloxacin according to the above-mentioned embodiments of the present application can also have the following additional technical features:

[0019] In some embodiments of the present application, 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 application, the mass ratio of CoSAs-PMOF, ciprofloxacin, and hydrogen peroxide is (4-5):(0.5-1):(15-20).

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

[0022] 1) The application is based on two-dimensional porphyrin metal materials, and a metal-organic framework material CoSAs-PMOF with interlayer confinement is prepared by a surfactant-assisted bottom-up method. Specifically, first, the precise embedding of single-atom Co is realized by means of a standard porphyrin template substrate, and then, by utilizing the coordination mode of porphyrin ligand and divalent copper ions, and with the auxiliary action of a surfactant and a regulator, a two-dimensional porphyrin metal-organic framework doped with single-atom Co is successfully synthesized. The two-dimensional porphyrin metal-organic framework is arranged in a layer-by-layer stacking manner, and there is a nanometer confinement space between the layers, while the single-atom Co in the layer is in this confinement environment. Compared with existing methods for constructing nanometer confinement spaces, on the one hand, the method proposed in the application has the advantages of simple operation and precise construction, and does not involve complex and 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 single-atom Co in the nanometer confinement environment corresponds one by one in the z-axis direction, can play a synergistic effect between single atoms, and thus selectively activates hydrogen peroxide to produce singlet oxygen, which is significantly different from existing methods.

[0023] 2) The application provides a new method for degrading CIP in water by using a confinement-based single-atom Co catalyst to activate hydrogen peroxide to produce active oxygen free radicals dominated by singlet oxygen. In the CoSAs-PMOF / H2O2 system, the highest degradation kinetic rate constant can reach 0.145 min −1 , which is 10 times that of TCPP-Cu (0.014 min −1 ) and 29 times that of CoSAs-TCPP (0.005 min −1 ). The characterization results of UV-Vis, FTIR, XRD, and XAS prove the successful embedding of the single-atom Co at the center of the metal porphyrin ring and the formation of the porphyrin-based metal-organic framework. In addition, the quenching results show that non-radical singlet oxygen plays a dominant role in the degradation experiment. The method provides a new idea for improving the performance of single-atom Fenton catalysts through nanometer confinement strategies.

[0024] 3) The two-dimensional porphyrin metal-organic framework involved in the application is arranged in a layer-by-layer stacking manner, and there is a confinement space with a spacing of 0.9 nm between the layers, while the single-atom Co in the layer is in this confinement environment and corresponds to each other in the z-axis direction. This unique arrangement enables the synergistic effect between the single-atom Co to be realized, and finally selectively converts hydrogen peroxide into singlet oxygen, achieving efficient removal of pollutants. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The ultraviolet-visible spectrum (UV-Vis) of CoSAs-TCPP prepared in Example 1 of the application and TCPP prepared in Comparative Example 2.

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

[0027] Figure 3 X-ray diffraction (XRD) characterization of CoSAs-PMOF prepared in Example 1 of the present application;

[0028] Figure 4 X-ray absorption spectroscopy (XAS) characterization of CoSAs-PMOF prepared in Example 1 of the present application;

[0029] Figure 5 Degradation amount-time graph of CIP in aqueous solution catalyzed by CoSAs-TCPP, TCPP-Cu and CoSAs-PMOF under H2O2 activation system in the application example of the present application;

[0030] Figure 6 Rate constant fitting graph of CIP in aqueous solution catalyzed by CoSAs-TCPP, TCPP-Cu and CoSAs-PMOF under H2O2 activation system in the application example of the present application;

[0031] Figure 7 Experiments of quenching CoSAs-PMOF / H2O2 system using different active species quenchers in the application example of the present application;

[0032] Figure 8 Kinetic rate constant graph of CIP removal by CoSAs-PMOF / H2O2 system under different quenchers in the application example of the present application;

[0033] Figure 9 Repeatability characterization graph of CoSAs-PMOF in the application example of the present application. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0035] Example 1

[0036] A preparation method of an interlayer confined Co single atom catalyst, comprising the following steps:

[0037] (1) 6.9 g of p-formyl benzoic acid methyl ester was dissolved in 100 mL of propionic acid in a 500 mL three-necked flask under nitrogen atmosphere, then the freshly purified pyrrole was added dropwise. The solution was refluxed at 150 °C for 18 hours. When the system was cooled, purple crystals of tetra(4-esterphenyl) porphyrin (TCPPOME) were obtained by suction filtration;

[0038] (2) A solution of 450 mg of ester-terminated porphyrin and 0.98 g of CoCl2 in 60 mL of N,N-dimethylformamide (DMF) was refluxed at 160 °C for 10 hours. After cooling, 150 mL of H2O was added to the above solution. The above solution was filtered several times through a 0.45 um organic filter membrane, and the collected filter cake was immediately dissolved in 100 ml of chloroform, and then the resulting solution was filtered again. The resulting filtrate was extracted with 1M hydrochloric acid and H2O three times, respectively, dried to obtain Co single atom doped tetra(4-esterphenyl) porphyrin (Co-TCPPOME);

[0039] (3) 480 mg of Co single atom doped ester-terminated porphyrin was stirred in 50 ml of (tetrahydrofuran-methanol) solvent with a volume ratio of 1:1. Then, 1.8 g of KOH in 20 mL of water 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 1M HCl was added dropwise to the solution until no more precipitate was formed. The green precipitate was collected by filtration, washed with water and vacuum dried. Finally, purple crystals of Co single atom doped tetra(4-carboxyphenyl) porphyrin (CoSAs-TCPP) were obtained;

[0040] (4) 2.4 mg of Cu(NO3)2·3H2O, 40 μL of formic acid and 10 mg of PVP were dissolved in 12 ml of DMF-EtOH solution with a volume ratio of 3:1. Then, 4.4 mg of CoSAs-TCPP was dissolved in a mixed solvent of 3 mL of DMF and 1 mL of ethanol under stirring, and then added to the above mixture in a 20 ml polytetrafluoroethylene liner, and reacted in an oven at 85 °C for 16 h; to obtain a Co single atom doped two-dimensional porphyrin metal organic framework dispersion.

[0041] (5) The obtained dispersion was first filtered by suction under a negative pressure of -0.1 MPa to collect the CoSAs-PMOF filter cake, and then washed with ethanol 6 times under this pressure to remove the unreacted reactants, with the ethanol used each time being 50 mL. Finally, the washed filter cake material was naturally air-dried to obtain a Co single atom doped two-dimensional porphyrin metal organic framework (CoSAs-PMOF).

[0042] Comparative Example 1

[0043] The method for preparing TCPP includes the following steps:

[0044] The 0.8 g of TCPP OME prepared in step (1) of Example 1 was stirred in 50 ml of a 1:1 (THF:MeOH) solvent. Then, 3.0 g of KOH in 25 mL of water 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 1M HC1 was added dropwise until no more precipitate was formed. The green precipitate was collected by filtration, washed with water, and dried under vacuum. Finally, purple crystals of tetrakis(4-carboxyphenyl) porphyrin (TCPP) were obtained.

[0045] Comparative Example 2

[0046] The method for preparing TCPP-Cu includes the following steps:

[0047] 2.4 mg of Cu(NO3)2·3H2O, 40 μL of formic acid, and 10 mg of PVP were dissolved in 12 ml of a DMF-EtOH solution at a volume ratio of 3:1. Then, 4.4 mg of TCPP was dissolved in a mixed solvent of 3 mL of DMF and 1 mL of ethanol under stirring, and then added to the above mixture in a 20 ml Teflon liner, and reacted in an oven at 85 °C for 16 h; a two-dimensional porphyrin metal-organic framework dispersion solution (TCPP-Cu) doped with Co single atoms was obtained.

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

[0049] The CoSAs-PMOF prepared in Example 1, CoSAs-TCPP, and TCPP-Cu prepared in Comparative Example 2 were subjected to Fourier transform infrared spectroscopy (FTIR) characterization, and the results are shown in Figure 2 . The strong peaks at 1240 cm -1 and 1678 cm -1 can be attributed to the stretching vibration of the COH and C=O bonds of the carboxyl group of the TCPP ligand. However, when the current body is connected to the MOF, these peaks become unobtrusive, while the peaks at 1420 cm -1 and 1620 cm -1A new absorption peak was observed, which corresponds to the stretching vibration of the CuO bond from Cu paddlewheel (Cu2(COO)4). These FTIR features indicate that CoSAs-TCPP was replaced by Cu 2+ Metal node successfully connected. The XRD pattern of CoSAs-PMOF shows characteristic peaks 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 shown in Figure 3 The XRD pattern of CoSAs-PMOF shows characteristic peaks at 7.6°, 8.9°, 19.46°, 21.4°, 23° and 30.5°, which is very consistent with the 2D-MOF structure. To elucidate 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). As shown in Figure 4 A significant peak of ≈1.48 Å was observed in the R-space map, corresponding to the first shell Co-N scattering path. Notably, no metal Co-Co bond was observed at 2.18 Å, and no Co-O peak was observed at 1.53 Å, which illustrates the atomically dispersed Co sites in the CoSAS-PMOF catalyst.

[0050] Application Example 1

[0051] A method for degrading ciprofloxacin, comprising the following steps:

[0052] (1) A simulated CIP wastewater solution with a concentration of 25 mg / L was prepared: 25 mg of CIP powder was first dissolved in 950 mL of water, then 1 mol / L hydrochloric acid solution and 1 mol / L sodium hydroxide solution were used to adjust the pH of the stock solution to 7.0, and finally the solution was quantitatively transferred to a 1 L volumetric flask. The concentration of ciprofloxacin (CIP) was analyzed and measured by high performance liquid chromatography (HPLC, Agilent), which was done by taking 200 μL of supernatant and adding it to a high performance liquid chromatography vial, which was then placed in a sample tray. The mobile phase eluent consisted of 0.3% formic acid and acetonitrile, with a flow rate of 1 mL / min.

[0053] (2) 4 mg of CoSAs-PMOF and CoSAs-TCPP prepared in Example 1, and TCPP-Cu prepared in Comparative Example 2, were added to 50 mL of 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] 2 mL of the reaction solution was taken at a certain time interval, the catalyst was filtered through a 0.22 μm PTFE filter to obtain the supernatant, and the CIP concentration in the solution was detected by high performance liquid chromatography, and the result was expressed as peak area, and the above operation was repeated twice. The initial peak area of the simulated CIP wastewater solution was recorded as C0, and the peak area at the corresponding time was recorded as C t , and C t / C0 as the ordinate and t as the abscissa to draw the degradation efficiency graph, and then select the first seven points in the graph, draw the degradation rate-time (C t / C0-t) according to the degradation rate-time (C t / C0-t), and process the steepest part in the degradation curve to obtain the maximum degradation rate constant K of the material.

[0055] Figures 5-6 The degradation rate-time (C t / C0-t) and the linear fitting graph of the degradation rate constant of CIP catalytic degradation in aqueous solution by CoSAs-TCPP, TCPP-Cu and CoSAs-PMOF under activated H2O2 system are shown in FIG. 2, FIG. 3 and FIG. 4, respectively. Figure 5 Compared with TCPP-Cu and CoSAs-TCPP, CoSAs-PMOF showed higher CIP degradation rate; Figure 6 The degradation rate constant in FIG. 4 also showed that CoSAs-PMOF had the highest CIP degradation rate constant, about 0.145 min −1 , which was 10.4 times and 29 times that of TCPP-Cu and CoSAs-TCPP, respectively. The above results showed that CoSAs-PMOF could efficiently activate hydrogen peroxide to degrade CIP.

[0056] By adding tert-butyl alcohol (TBA, 2.39 mL), p-benzoquinone (p-BQ, 27.025 mg) and furfuryl alcohol (FFA, 2.16 mL) as hydroxyl radical (·OH), superoxide radical (·O2) and singlet oxygen 1 O2 scavengers in the CoSAs-PMOF activated H2O2 degradation CIP system in step (2) of the ciprofloxacin degradation method, the types of active oxygen species were identified.

[0057] A blank control experiment was set up: 4 mg of CoSAs-PMOF prepared in Example 1 was added to 50 mL of 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] As shown in FIG. 5, the degradation rate of CIP in the blank control experiment was very slow, and the degradation rate constant was only 0.002 min Figure 7As shown, after the introduction of tert-butyl alcohol (TBA) and p-benzoquinone (P-BQ) into the reaction system, the inhibition effect on the degradation efficiency of CIP was only 9.018% and 28.397%, which indicated that OH and ·O2 played a limited catalytic role in the oxidation process. However, FFA showed a significant inhibition rate (73.004%) on the degradation of CIP, while Figure 8 The inhibition degradation rate constant in the figure also showed that the rate constant was reduced to the minimum of 0.003 min −1 , which indicated that 1 O2 was the main dominant species involved in the process of CoSAs-PMOF activating H2O2.

[0059] The repeatability of the prepared material CoSAs-PMOF was detected, and the results are shown in Figure 9 As shown, after the material was subjected to 5 consecutive degradation tests, the degradation efficiency could still be maintained above 75%.

[0060] The above is only an example and description of the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or adopt similar ways to replace them, as long as they do not deviate from the structure of the present application or exceed the scope defined by the present claims.

Claims

1. A method for preparing a Co single-atom catalyst confined in interlayer space, characterized in that, Includes the following steps: First, a cobalt single atom is inserted into the center of the porphyrin ring to obtain a porphyrin ligand with an embedded Co single atom. Then, a one-step organic solvothermal synthesis method is used to combine the cluster metal ion with the porphyrin ligand with the embedded Co single atom to prepare a porphyrin-based metal-organic framework CoSAs-PMOF, which is the interlayer confined Co single atom catalyst. The embedding of a cobalt single atom at the center of the porphyrin ring specifically includes the following steps: (1) Under a nitrogen atmosphere, methyl p-formylbenzoate was dissolved in propionic acid, and then freshly purified pyrrole was added dropwise. The solution was refluxed at 140℃-160℃ for 12-24 hours. After cooling, purple crystals TCPPOME were obtained by vacuum filtration. (2) Reflux TPPCOOME and CoCl2 in N,N-dimethylformamide solution at 140-160℃ for 6-12 h. After cooling, add H2O to the solution and filter it through an organic filter membrane several times. Dissolve the collected filter cake in chloroform immediately and filter the solution again. Extract the filtrate with hydrochloric acid and H2O several times and dry it to obtain Co-TCPPOME. (3) Co-TCPPOME was stirred in tetrahydrofuran-methanol solvent, KOH aqueous solution was added, and refluxed at 80-100℃ for 10-16 hours. During the cooling process, tetrahydrofuran and methanol were evaporated, water was added to the remaining mixture, and then 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 under vacuum to finally obtain purple crystals CoSAs-TCPP. The organic solvent thermal synthesis step specifically includes the following steps: First, Cu(NO3)2·3H2O, formic acid, and polyvinylpyrrolidone were dissolved in a mixed solvent of N,N-dimethylformamide and anhydrous ethanol to obtain a mixed solution. CoSAs-TCPP was 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 was then reacted in an oven at 80-90℃ for 12-24 h. The resulting solution was filtered, washed, and dried to obtain porphyrin-based metal-organic framework CoSAs-PMOF.

2. The method for preparing a Co single-atom catalyst confined within an interlayer according to claim 1, characterized in that: In step (1), the mass ratio of methyl paraformylbenzoate 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 μm; In step (3), the mass ratio of Co-TCPPOME to KOH is 1:(3-4).

3. The method for preparing a Co single-atom catalyst confined within an interlayer according to claim 1, 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).

4. A Co single-atom catalyst with interlayer confinement prepared by a method according to any one of claims 1-3.

5. A method for degrading ciprofloxacin, characterized in that: Hydrogen peroxide is activated using the interlayer confined Co single-atom catalyst described in claim 4 to generate reactive oxygen free radicals dominated by singlet oxygen, which are then used to degrade ciprofloxacin.

6. The method for degrading ciprofloxacin according to claim 5, characterized in that, Includes the following steps: CoSAs-PMOF was dispersed in a ciprofloxacin solution, and then hydrogen peroxide solution was added.

7. The method for degrading ciprofloxacin according to claim 6, characterized in that: The mass ratio of CoSAs-PMOF, ciprofloxacin, and hydrogen peroxide is (4-5):(0.5-1):(15-20).

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