High-activity Mn / CeO2 nano-enzyme prepared from Ce-MOFs and preparation method

Abstract

The invention provides a high-activity Mn / CeO2 nano-enzyme prepared through Ce-MOFs and a preparation method, and relates to the technical field of functional materials, Ce-MOFs is used as a precursor, Mn element is introduced into Ce-MOFs by utilizing coordination of an organic ligand in Ce-MOFs and Mn < 2 + >, and the Mn / CeO2 nano-enzyme is prepared through derivation after heat treatment. In the heat treatment process, organic ligands in the MOFs are decomposed, so that the pyrolyzed CeO2 presents a loose porous structure. Due to the existence of coordination, Mn in the obtained nano-enzyme is uniformly dispersed and is in close contact with CeO2, and the content of Mn is very easy to control. The nano enzyme shows oxidase-like activity and excellent peroxidase-like activity, and has good potential application in numerous fields.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials, and in particular to a high-activity Mn / CeO2 nanozyme prepared by Ce-MOFs and a preparation method thereof. Background Art

[0002] Nanozymes, as an emerging artificial enzyme mimic, are receiving more and more attention due to their excellent performance. Compared with natural enzymes, nanozymes have the advantages of high stability, low production cost, and large-scale preparation. At the same time, nanozymes also have high catalytic activity, which makes them have good applications in sensing, disease diagnosis / treatment, antibacterial / antibacterial fields. So far, a variety of nanozymes have been designed and synthesized, but due to performance limitations, practical nanozymes are still lacking. Therefore, new methods need to be designed to synthesize nanozymes to enhance their performance.

[0003] Bimetallic composites are an effective means to enhance the performance of nanozymes. Some researchers used a one-pot method to prepare a composite nanozyme of Mn and Co3O4 (Analytical Biochemistry, 2022, 654: 114818), which achieved an increase in the activity of oxidase-like and peroxidase-like enzymes. However, it is difficult to achieve full mixing between the two metal elements in the bimetallic composite nanozyme prepared by this conventional method, which is not conducive to giving full play to the advantages of the two metal elements. In recent years, nanozymes derived from MOFs have become a hot topic of research, not only because MOFs have rich pore structures and large specific surface areas, but also because of the topological structure of MOFs and the adjustability of metal sites. A research group synthesized bimetallic MOFs of Fe and Ni, and subsequently obtained an Fe, Ni composite nanozyme by calcination under an argon atmosphere. The nanozyme exhibited enhanced peroxidase-like activity (Talanta, 2024, 276: 126207). Although this method of deriving bimetallic composite nanozymes from bimetallic MOFs can improve the mixing degree of the two components and improve the performance to a certain extent, the phase separation problem in the synthesis process of most bimetallic MOFs is difficult to avoid. Therefore, developing a simple and efficient method to further enhance the favorable contact between the two components in MOFs-derived bimetallic nanozymes and improve the performance of nanozymes is of great significance for the practical application of nanozymes. Summary of the invention

[0004] In view of the defects in the prior art, the object of the present invention is to provide a highly active Mn / CeO2 nanozyme prepared by Ce-MOFs and a preparation method thereof.

[0005] According to one aspect of the present invention, a highly active Mn / CeO prepared by Ce-MOFs is provided. 2Nanozymes, using Ce-MOFs as precursors, utilize organic ligands in Ce-MOFs to bind to Mn 2+ The Mn element was introduced into Ce-MOFs by the coordination effect, and Mn / CeO was derived after heat treatment. 2 Nanozyme, wherein the loading amount of Mn is 0wt% to 5wt%;

[0006] Mn / CeO 2 The nanozyme is slender and loosely porous, with a diameter of less than 200 nm and a length of less than 2000 nm. 2 Nanozymes have both oxidase-like activity and ultra-high peroxidase-like activity.

[0007] The present invention provides a highly active Mn / CeO prepared by Ce-MOFs. 2 The preparation method of nanozyme, the specific steps are as follows:

[0008] S1, H 3 BTC is dissolved in an organic solvent and heated in an oil bath at a certain temperature to obtain solution A; Ce(NO3) 3 6H2O is dissolved in ultrapure water to obtain solution B; solution A and solution B are mixed and reacted while maintaining the temperature and stirring, and Ce-MOFs are obtained after the reaction;

[0009] S2, Mn(NO3) 2 4H2O is dissolved in methanol, and the Ce-MOFs prepared in step S1 are added. After being mixed evenly, the mixture is transferred into a hydrothermal reactor to react under certain conditions. After the reaction is completed, Mn / Ce-MOFs are obtained.

[0010] S3. Heat-treating the Mn / Ce-MOFs prepared in step B under certain conditions to obtain Mn / CeO2 nanozymes.

[0011] Preferably, in the above step S1, the organic solvent is a mixed solvent of ultrapure water / anhydrous ethanol (1:1).

[0012] Preferably, the usage ratio of H3BTC and ultrapure water / ethanol mixed solvent is 1 mmol:20 mL.

[0013] Preferably, in the above step S1, Ce(NO3) 3 The usage ratio of 6H2O and ultrapure water is 1mmol:45mL.

[0014] Preferably, in the above step S2, Mn(NO 3 ) 2 ·4H 2The usage ratio of O, methanol and Ce-MOFs is (0-200 mg): 20 mL: 500 mg.

[0015] Preferably, in the above step S2, the temperature of the hydrothermal reaction is 110-130° C., and the time of the hydrothermal reaction is 1-4 h.

[0016] Preferably, in the above step S3, the heat treatment temperature is 380-420° C., the heat treatment time is 1.5-2.5 h, and the heat treatment atmosphere is air atmosphere.

[0017] Preferably, the highly active Mn / CeO prepared by Ce-MOFs 2 The preparation method of nanozyme, the specific steps are as follows:

[0018] S1. Dissolve H3BTC in a mixed solvent of ultrapure water / anhydrous ethanol (1:1), heat and stir in an oil bath at 50-70°C; dissolve Ce(NO3)3·6H2O in ultrapure water; mix the two solutions and keep the temperature and stirring for 1-2h; after the reaction, centrifuge, wash with water and ethanol, and dry at 65-75°C to obtain Ce-MOFs;

[0019] S2, dissolving Mn(NO3)2·4H2O in methanol, adding Ce-MOFs prepared in step S1, mixing evenly and transferring to a hydrothermal reactor to react under certain conditions, and after the reaction, centrifuging, washing, and drying at 65-75°C to obtain Mn / Ce-MOFs;

[0020] S3. Heat-treating the Mn / Ce-MOFs prepared in step B under air atmosphere to obtain Mn / CeO2 nanozymes.

[0021] Preferably, the highly active Mn / CeO prepared by Ce-MOFs 2 The preparation method of nanozyme, the specific steps are as follows:

[0022] S1. Dissolve H3BTC in a mixed solvent of ultrapure water / anhydrous ethanol (1:1), heat and stir in an oil bath at 60°C; dissolve Ce(NO3)3·6H2O in ultrapure water; mix the two solutions and keep the temperature and stirring for 1 hour; after the reaction, centrifuge, wash with water and ethanol, and dry at 70°C to obtain Ce-MOFs;

[0023] S2, dissolving Mn(NO3)2·4H2O in methanol, adding Ce-MOFs prepared in step S1, mixing evenly and transferring into a hydrothermal reactor for reaction, the hydrothermal reaction temperature is 110-130°C, and the hydrothermal reaction time is 1-4h; after the reaction, centrifuging, washing, and drying at 70°C to obtain Mn / Ce-MOFs;

[0024] S3. The Mn / Ce-MOFs prepared in step B are heat-treated in an air atmosphere at a temperature of 380-420° C. for a time of 1.5-2.5 h to obtain Mn / CeO2 nanozymes.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention uses Ce-MOFs as a precursor, utilizes the coordination effect between the organic ligands in Ce-MOFs and Mn2+ to introduce the Mn element into Ce-MOFs, and obtains the Mn / CeO2 nanozyme by simple heat treatment; and the method of introducing Mn by utilizing the coordination effect of the organic ligands in MOFs is simple and efficient, provides a highly active bimetallic composite nanozyme, and enriches the method of preparing highly active bimetallic nanozymes using MOFs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0028] Figure 1 The scanning electron microscope image of Ce-MOFs prepared in Example 3-9;

[0029] Figure 2 The scanning electron microscope images and transmission electron microscope images of the Mn / Ce-MOFs and Mn / CeO2 nanozymes prepared in Example 3 are shown in FIG. a. The scanning electron microscope image of the Mn / Ce-MOFs prepared in Example 3 is shown in FIG. b. The scanning electron microscope image of the Mn / CeO2 nanozyme prepared in Example 3 is shown in FIG. c. The transmission electron microscope image of the Mn / CeO2 nanozyme prepared in Example 3 is shown in FIG.

[0030] Figure 3 XRD patterns of the Mn / CeO2 nanozymes prepared in Example 3, Example 4, Example 8, Example 6, and Example 9;

[0031] Figure 4 The peroxidase-like activity test results of the Mn / CeO2 nanozymes prepared in Example 3, Example 4, Example 5, Example 6, and Example 7;

[0032] Figure 5 The Mn / CeO prepared in Example 3 2 Elemental distribution map of nanozyme in HAADF-STEM mode. DETAILED DESCRIPTION

[0033] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0034] Example 1

[0035] The present invention provides a high-activity Mn / CeO prepared by Ce-MOFs 2 Nanozymes, using Ce-MOFs as precursors, utilize organic ligands in Ce-MOFs to bind to Mn 2+ The Mn element was introduced into Ce-MOFs by the coordination effect, and Mn / CeO was derived after heat treatment. 2 Nanozyme, wherein the loading amount of Mn is 0wt% to 5wt%;

[0036] Mn / CeO 2 The nanozyme is slender and loosely porous, with a diameter of less than 200 nm and a length of less than 2000 nm. 2 Nanozymes have both oxidase-like activity and ultra-high peroxidase-like activity.

[0037] Example 2

[0038] The present invention also provides a high-activity Mn / CeO prepared by Ce-MOFs. 2 The preparation method of nanozyme comprises the following steps:

[0039] S1, H 3 BTC was dissolved in a mixed solvent of ultrapure water / anhydrous ethanol (1:1) and heated in an oil bath at a certain temperature to obtain solution A; Ce(NO3) 3 6H2O is dissolved in ultrapure water to obtain solution B; preferably, the amount ratio of H3BTC and ultrapure water / ethanol mixed solvent is 1mmol:20mL; Ce(NO3) 3 The dosage ratio of 6H2O and ultrapure water is 1mmol:45mL; Solution A and Solution B are mixed and reacted while maintaining the temperature and stirring, and Ce-MOFs are obtained after the reaction;

[0040] S2, Mn(NO3) 2 ·4H2O was dissolved in methanol and Ce-MOFs, Mn(NO 3 ) 2 ·4H 2The amount ratio of O, methanol and Ce-MOFs is (0-200 mg): 20 mL: 500 mg; after being evenly mixed, the mixture is transferred into a hydrothermal reactor for reaction. The temperature of the hydrothermal reaction is 110-130°C and the time of the hydrothermal reaction is 1-4 h. After the reaction, Mn / Ce-MOFs is obtained;

[0041] S3. The Mn / Ce-MOFs prepared in step B are heat-treated under certain conditions, the heat treatment temperature is 380-420°C, the heat treatment time is 1.5-2.5h, and the heat treatment atmosphere is an air atmosphere to obtain Mn / CeO2 nanozyme.

[0042] Example 3

[0043] This embodiment 3 is a preferred example completed on the basis of embodiment 2, and includes the following steps:

[0044] S1. Dissolve 2.1 g H3BTC in 20 mL ultrapure water / anhydrous ethanol (1:1) mixed solvent, heat in 60 °C oil bath and stir; dissolve 4.34 g Ce(NO3)3·6H2O in 45 mL ultrapure water; mix the two solutions and keep the temperature and stirring for 1 h; after the reaction, centrifuge, wash with water and ethanol, and dry at 70 °C to obtain Ce-MOFs;

[0045] S2, dissolving 180 mg of Mn(NO3)2·4H2O in 20 mL of methanol, adding 500 mg of Ce-MOFs prepared in step S1, mixing evenly, transferring to a hydrothermal reactor and reacting at 120°C for 2 h, and after the reaction, centrifuging, washing, and drying at 70°C to obtain Mn / Ce-MOFs;

[0046] S3. Heat-treat the Mn / Ce-MOFs prepared in step S2 at 400°C in an air atmosphere for 2 h to obtain Mn / CeO2 nanozymes.

[0047] The Mn loading amount in the Mn / CeO2 nanozyme obtained in this embodiment is 4.68wt%, and only the diffraction peak of CeO2 is shown in XRD. The morphology is a loose porous structure, and the three elements of Mn, Ce, and O are evenly distributed. The peroxidase-like activity exhibited is the highest, which is the optimal item.

[0048] Example 4

[0049] This embodiment 3 is a preferred example completed on the basis of embodiment 2, and includes the following steps:

[0050] S1. Dissolve 2.1 g H3BTC in 20 mL ultrapure water / anhydrous ethanol (1:1) mixed solvent, heat and stir in a 60 °C oil bath; dissolve 4.34 g Ce(NO3)3·6H2O in 45 mL ultrapure water; mix the two solutions and keep the temperature and stirring for 1 hour; after the reaction, centrifuge, wash with water and ethanol, and dry at 70 °C to obtain Ce-MOFs.

[0051] S2. Dissolve 90 mg of Mn(NO3)2·4H2O in 20 mL of methanol, add 500 mg of Ce-MOFs prepared in step S1, mix well and transfer into a hydrothermal reactor to react at 120°C for 2 h. After the reaction, centrifuge, wash and dry at 70°C to obtain Mn / Ce-MOFs.

[0052] S3. Heat-treat the Mn / Ce-MOFs prepared in step S2 at 400°C in an air atmosphere for 2 h to obtain Mn / CeO2 nanozymes.

[0053] The Mn loading amount in the Mn / CeO2 nanozyme obtained in this example is 3.33 wt %, and only the diffraction peak of CeO2 is shown in XRD. The peroxidase-like activity exhibited is second only to the nanozyme synthesized in Example 3.

[0054] Example 5

[0055] This embodiment 5 is a preferred example completed on the basis of embodiment 2, and includes the following steps:

[0056] S1. Dissolve 2.1 g H3BTC in 20 mL ultrapure water / anhydrous ethanol (1:1) mixed solvent, heat and stir in a 60 °C oil bath; dissolve 4.34 g Ce(NO3)3·6H2O in 45 mL ultrapure water; mix the two solutions and keep the temperature and stirring for 1 hour; after the reaction, centrifuge, wash with water and ethanol, and dry at 70 °C to obtain Ce-MOFs.

[0057] S2. Dissolve 45 mg of Mn(NO3)2·4H2O in 20 mL of methanol, add 500 mg of Ce-MOFs prepared in step S1, mix well and transfer into a hydrothermal reactor to react at 120°C for 2 h. After the reaction, centrifuge, wash and dry at 70°C to obtain Mn / Ce-MOFs.

[0058] S3. Heat-treat the Mn / Ce-MOFs prepared in step S2 at 400°C in an air atmosphere for 2 h to obtain Mn / CeO2 nanozymes.

[0059] The Mn loading amount in the Mn / CeO2 nanozyme obtained in this example is 2.77 wt %, and only the diffraction peak of CeO2 is shown in XRD. The peroxidase-like activity exhibited is inferior to that of the nanozymes synthesized in Examples 3 and 4.

[0060] Example 6

[0061] This embodiment 6 is a preferred example completed on the basis of embodiment 2, and includes the following steps:

[0062] S1. Dissolve 2.1 g H3BTC in 20 mL ultrapure water / anhydrous ethanol (1:1) mixed solvent, heat and stir in a 60 °C oil bath; dissolve 4.34 g Ce(NO3)3·6H2O in 45 mL ultrapure water; mix the two solutions and keep the temperature and stirring for 1 hour; after the reaction, centrifuge, wash with water and ethanol, and dry at 70 °C to obtain Ce-MOFs.

[0063] S2. Dissolve 24 mg of Mn(NO3)2·4H2O in 20 mL of methanol, add 500 mg of Ce-MOFs prepared in step S1, mix well and transfer into a hydrothermal reactor to react at 120°C for 2 h. After the reaction, centrifuge, wash and dry at 70°C to obtain Mn / Ce-MOFs.

[0064] S3. Heat-treat the Mn / Ce-MOFs prepared in step S2 at 400°C in an air atmosphere for 2 h to obtain Mn / CeO2 nanozymes.

[0065] The Mn loading amount in the Mn / CeO2 nanozyme obtained in this example is 0.78 wt %, and only the diffraction peak of CeO2 is shown in XRD. The peroxidase-like activity exhibited is inferior to that of the nanozyme synthesized in Examples 3-5.

[0066] Example 7

[0067] This embodiment 7 is a preferred example completed on the basis of embodiment 2, and includes the following steps:

[0068] S1. Dissolve 2.1 g H3BTC in 20 mL ultrapure water / anhydrous ethanol (1:1) mixed solvent, heat and stir in a 60 °C oil bath; dissolve 4.34 g Ce(NO3)3·6H2O in 45 mL ultrapure water; mix the two solutions and keep the temperature and stirring for 1 hour; after the reaction, centrifuge, wash with water and ethanol, and dry at 70 °C to obtain Ce-MOFs.

[0069] S2. Dissolve 12 mg of Mn(NO3)2·4H2O in 20 mL of methanol, add 500 mg of Ce-MOFs prepared in step S1, mix well and transfer into a hydrothermal reactor to react at 120°C for 2 h. After the reaction, centrifuge, wash and dry at 70°C to obtain Mn / Ce-MOFs.

[0070] S3. Heat-treat the Mn / Ce-MOFs prepared in step S2 at 400°C in an air atmosphere for 2 h to obtain Mn / CeO2 nanozymes.

[0071] The Mn loading amount in the Mn / CeO2 nanozyme obtained in this example is 0.50wt%, and only the diffraction peak of CeO2 is shown in XRD. The peroxidase-like activity exhibited is inferior to that of the nanozymes synthesized in Examples 3-6.

[0072] Example 8

[0073] This embodiment 8 is a preferred example completed on the basis of embodiment 2, and includes the following steps:

[0074] S1. Dissolve 2.1 g H3BTC in 20 mL ultrapure water / anhydrous ethanol (1:1) mixed solvent, heat and stir in a 60 °C oil bath; dissolve 4.34 g Ce(NO3)3·6H2O in 45 mL ultrapure water; mix the two solutions and keep the temperature and stirring for 1 hour; after the reaction, centrifuge, wash with water and ethanol, and dry at 70 °C to obtain Ce-MOFs.

[0075] S2. Dissolve 45 mg of Mn(NO3)2·4H2O in 20 mL of methanol, add 500 mg of Ce-MOFs prepared in step S1, mix well and transfer into a hydrothermal reactor to react at 120°C for 4 h. After the reaction, centrifuge, wash and dry at 70°C to obtain Mn / Ce-MOFs.

[0076] S3. Heat-treat the Mn / Ce-MOFs prepared in step S2 at 400°C in an air atmosphere for 2 h to obtain Mn / CeO2 nanozymes.

[0077] The Mn loading amount in the Mn / CeO2 nanozyme obtained in this example is 2.80wt%, and only the diffraction peak of CeO2 is shown in XRD. The peroxidase-like activity exhibited is similar to that of the nanozyme synthesized in Example 5.

[0078] Example 9

[0079] This embodiment 9 is a preferred example completed on the basis of embodiment 2, and includes the following steps:

[0080] S1. Dissolve 2.1 g H3BTC in 20 mL ultrapure water / anhydrous ethanol (1:1) mixed solvent, heat and stir in a 60 °C oil bath; dissolve 4.34 g Ce(NO3)3·6H2O in 45 mL ultrapure water; mix the two solutions and keep the temperature and stirring for 1 hour; after the reaction, centrifuge, wash with water and ethanol, and dry at 70 °C to obtain Ce-MOFs.

[0081] S2. Dissolve 12 mg of Mn(NO3)2·4H2O in 20 mL of methanol, add 500 mg of Ce-MOFs prepared in step S1, mix well and transfer into a hydrothermal reactor to react at 120°C for 1 h. After the reaction, centrifuge, wash and dry at 70°C to obtain Mn / Ce-MOFs.

[0082] S3. Heat-treat the Mn / Ce-MOFs prepared in step S2 at 400°C in an air atmosphere for 2 h to obtain Mn / CeO2 nanozymes.

[0083] The Mn loading amount in the Mn / CeO2 nanozyme obtained in this example is 0.48 wt %, and only the diffraction peak of CeO2 is shown in XRD. The peroxidase-like activity exhibited is similar to that of the nanozyme synthesized in Example 7.

[0084] like Figure 1-5 As shown in the figure, the synthesized Ce-MOFs are slender rods with a diameter of less than 200nm and a length of less than 3000nm. 2 The morphology and diameter of the nanozymes are the same as those of Ce-MOFs, and the length is less than 2000nm. 2 Nanozymes only present CeO 2 The diffraction peaks of Mn / CeO show that the Mn species are well dispersed to a certain extent. The element distribution characterization results also prove that the Mn / CeO 2 The uniform dispersion of Mn species in nanozymes. The enzyme activity test results show that Mn / CeO 2 The peroxidase-like activity of the nanozyme increased with the increase of Mn loading.

[0085] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0086] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A highly active Mn / CeO2 nanozyme prepared by Ce-MOFs, characterized in that: Ce-MOFs are used as precursors and the organic ligands in Ce-MOFs react with Mn 2+ The Mn element is introduced into Ce-MOFs by the coordination effect of , and the Mn / CeO2 nanozyme is derived after heat treatment; wherein the loading amount of Mn is 0wt% to 5wt%; The morphology of Mn / CeO2 nanozyme is slender rod-like and loose and porous, with a diameter of less than 200nm and a length of less than 2000nm; and Mn / CeO2 nanozyme has both oxidase-like activity and ultra-high peroxidase-like activity.

2. A method for preparing highly active Mn / CeO2 nanozymes prepared by Ce-MOFs, characterized in that: The specific steps are as follows: S1. Dissolve H3BTC in an organic solvent and heat it in an oil bath at a certain temperature to obtain solution A; dissolve Ce(NO3)3·6H2O in ultrapure water to obtain solution B; mix solution A and solution B and maintain the temperature and stir to react, and obtain Ce-MOFs after the reaction; S2, dissolving Mn(NO3)2·4H2O in methanol, adding Ce-MOFs prepared in step S1, mixing evenly and transferring into a hydrothermal reactor to react under certain conditions, and obtaining Mn / Ce-MOFs after the reaction; S3. Heat-treating the Mn / Ce-MOFs prepared in step B under certain conditions to obtain Mn / CeO2 nanozymes.

3. The method for preparing a highly active Mn / CeO2 nanozyme prepared by Ce-MOFs according to claim 2, characterized in that: In the above step S1, the organic solvent is a mixed solvent of ultrapure water / anhydrous ethanol (1:1).

4. According to the claim 3 The method for preparing the highly active Mn / CeO2 nanozyme prepared by Ce-MOFs is characterized in that: In the above step S1, the usage ratio of H3BTC and ultrapure water / ethanol mixed solvent is 1 mmol:20 mL.

5. The method for preparing a highly active Mn / CeO2 nanozyme prepared by Ce-MOFs according to claim 2, characterized in that: In the above step S1, the usage ratio of Ce(NO3)3·6H2O and ultrapure water is 1 mmol:45 mL.

6. The method for preparing a highly active Mn / CeO2 nanozyme prepared by Ce-MOFs according to claim 2, characterized in that: In the above step S2, the usage ratio of Mn(NO3)2·4H2O, methanol and Ce-MOFs is (0-200 mg): 20 mL: 500 mg.

7. The method for preparing a highly active Mn / CeO2 nanozyme prepared by Ce-MOFs according to claim 2, characterized in that: In the above step S2, the temperature of the hydrothermal reaction is 110-130° C., and the time of the hydrothermal reaction is 1-4 hours.

8. The method for preparing highly active Mn / CeO2 nanozymes prepared by Ce-MOFs according to claim 2, characterized in that: In the above step S3, the heat treatment temperature is 380-420° C., the heat treatment time is 1.5-2.5 hours, and the heat treatment atmosphere is air atmosphere.

9. The method for preparing highly active Mn / CeO2 nanozymes prepared by Ce-MOFs according to claim 2, characterized in that: S1. Dissolve H3BTC in a mixed solvent of ultrapure water / anhydrous ethanol (1:1), heat and stir in an oil bath at 50-70°C; dissolve Ce(NO3)3·6H2O in ultrapure water; mix the two solutions and keep the temperature and stirring for 1-2h; after the reaction, centrifuge, wash with water and ethanol, and dry at 65-75°C to obtain Ce-MOFs; S2, dissolving Mn(NO3)2·4H2O in methanol, adding Ce-MOFs prepared in step S1, mixing evenly and transferring to a hydrothermal reactor to react under certain conditions, and after the reaction, centrifuging, washing, and drying at 65-75°C to obtain Mn / Ce-MOFs; S3. Heat-treating the Mn / Ce-MOFs prepared in step B under air atmosphere to obtain Mn / CeO2 nanozymes.

10. The method for preparing highly active Mn / CeO2 nanozymes prepared by Ce-MOFs according to claim 2, characterized in that: The specific steps are as follows: S1. Dissolve H3BTC in a mixed solvent of ultrapure water / anhydrous ethanol (1:1), heat and stir in an oil bath at 60°C; dissolve Ce(NO3)3·6H2O in ultrapure water; mix the two solutions and keep the temperature and stirring for 1 hour; after the reaction, centrifuge, wash with water and ethanol, and dry at 70°C to obtain Ce-MOFs; S2, dissolving Mn(NO3)2·4H2O in methanol, adding Ce-MOFs prepared in step S1, mixing evenly and transferring into a hydrothermal reactor for reaction, the hydrothermal reaction temperature is 110-130°C, and the hydrothermal reaction time is 1-4h; after the reaction, centrifuging, washing, and drying at 70°C to obtain Mn / Ce-MOFs; S3. The Mn / Ce-MOFs prepared in step B are heat-treated in an air atmosphere at a temperature of 380-420° C. for a time of 1.5-2.5 h to obtain Mn / CeO2 nanozymes.

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