Two-dimensional iron boride nano-enzyme with peroxidase-like activity as well as preparation method and application of two-dimensional iron boride nano-enzyme

Abstract

The invention belongs to but not limited to the technical field of nano-materials, and discloses a two-dimensional iron boride nano-enzyme with POD-like activity as well as a preparation method and application of the two-dimensional iron boride nano-enzyme. The preparation method comprises the following steps: sufficiently grinding ferroferric oxide, boron powder, sodium chloride and potassium chloride according to a certain mass ratio, and then calcining at high temperature under the protection of inert gas. Then, centrifugal washing is conducted through water and ethyl alcohol, drying is conducted under the vacuum condition, and the 2D FeB nano-enzyme is obtained. The obtained 2D FeB nano-enzyme has antioxidant performance of scavenging free radicals, and shows good POD-like activity and good performance in detection of natural antioxidants and evaluation of total antioxidant activity of tea leaves. The 2D FeB nano-enzyme is successfully prepared through a high-temperature molten salt method for the first time. Compared with a high-temperature solid-phase reaction method and a chemical vapor deposition method, the method has the advantages that the adopted preparation conditions are simpler, the raw materials are easy to obtain, and the method has good repeatability, high yield and lower energy consumption.

Description

Technical Field

[0001] The present invention belongs to, but is not limited to, the technical field of nanomaterials, and particularly relates to a two-dimensional iron boride nanozyme with peroxidase-like activity, a preparation method thereof, and an application thereof. Background Art

[0002] Enzymes are a special type of protein in living organisms. As biological catalysts, they play a crucial role in living organisms. The activity of enzymes is affected by many factors, including temperature, pH value, substrate concentration, etc. Nanozymes refer to enzyme molecules with nanoscale sizes or enzyme systems based on nanotechnology. Due to their better environmental compatibility, large-scale preparation, and customizable activity compared with traditional enzymes, nanozymes have broad application prospects in the fields of biology, medicine, environmental protection, and biotechnology. Two-dimensional materials have characteristics such as a large specific surface area, adjustable electronic structure, high carrier mobility, and controllable chemical reactivity. In recent years, reported two-dimensional material nanozymes include transition metal oxides such as cerium oxide, iron tetroxide, and cobalt tetroxide. In addition, there are also MXenes, transition metal sulfides, and transition metal selenides. A large number of studies have shown that materials containing variable-valence metals and prone to redox reactions exhibit excellent performance in enzyme-like catalytic applications. Given the unique boron structure variants contained in two-dimensional transition metal boride materials, and their complex and multi-transforming structures, which are unparalleled by other inorganic materials, it is expected to achieve highly active and efficient enzyme-like catalysis, bringing new opportunities for the expansion and application of new materials in the field of nanozymes. However, due to the harsh preparation conditions and high cost of transition metal borides, and the lack of a preparation method with adjustable morphology, it has affected their application in related fields.

[0003] In view of the above analysis, the technical problems urgently to be solved in the prior art are: harsh preparation conditions, high cost, and the lack of a preparation method with adjustable morphology. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention provides a two-dimensional iron boride (2D FeB) nanozyme with peroxidase-like (POD) activity, a preparation method thereof, and an application thereof.

[0005] The present invention is realized as follows. A preparation method of a two-dimensional iron boride nanozyme with POD-like activity includes the following steps:

[0006] Step 1: Weigh a certain amount of iron tetroxide powder, boron powder, sodium chloride, and potassium chloride, and mix and grind them.

[0007] Step 2: Transfer the ground powder to an appropriate container, and under a protective atmosphere, perform high-temperature calcination treatment, and then cool the sample after high-temperature calcination naturally or under controlled conditions.

[0008] Step 3: Centrifuge and wash the product after high-temperature calcination. Use an alternating washing method with water and ethanol, and then place the washed product in a vacuum drying oven for drying to obtain a 2D FeB nanozyme sample.

[0009] Further, the iron oxide in Step 1 is nano-sized powder with a particle size less than 20 μm; the particle size of the boron powder is 10 - 20 μm.

[0010] Further, in Step 1, place the iron oxide powder, boron powder, sodium chloride, and potassium chloride together in an agate mortar for mixing and grinding; the mass ratio of iron oxide, boron powder, sodium chloride, and potassium chloride is 1 - 6:3 - 7:0 - 50:0 - 50 (sodium chloride and potassium chloride cannot be 0 at the same time), and grind in the agate mortar for 10 min - 1 h to make them fully dispersed without a granular feeling.

[0011] Further, in Step 2, the powder is calcined in a tube furnace under a nitrogen or argon atmosphere to ensure that there is no oxygen in the reaction environment; the tube furnace is heated to 780°C - 1100°C at a rate of more than 10°C / min, then held at this temperature for 5 - 120 min, and then allowed to cool down naturally.

[0012] Further, in Step 3, the centrifuge washing speed is 8000 r / min - 12000 r / min, and use an alternating washing method with water and ethanol more than three times, and use ethanol for the last wash. The temperature of the water is 80°C - 100°C.

[0013] Further, in Step 3, place the obtained product in a vacuum drying oven and continuously vacuum dry it at 60°C for 8 hours to finally obtain a 2D FeB nanozyme product.

[0014] Another object of the present invention is to provide a two-dimensional iron boride nanozyme with POD-like activity prepared by the preparation method of the two-dimensional iron boride nanozyme with POD-like activity. It has a complete two-dimensional planar structure, and the atomic ratio of Fe / B in 2D FeB is 1:1, showing good POD-like activity, which is about 20 times that of nano iron oxide, and can catalyze H2O2 to produce ·OH. In the determination of the Michaelis constant related to POD activity, the Michaelis constant (K m ) of FeB for the substrate TMB is 0.344827 mM, and the Michaelis constant for the substrate H2O2 is 0.07973 mM, and the Michaelis constant for the substrate H2O2 is lower.

[0015] Another object of the present invention is to provide an application of a two-dimensional FeB nanozyme with POD-like activity in detecting natural antioxidants and evaluating the antioxidant activities of different teas.

[0016] Combined with the above technical solutions and the technical problems to be solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0017] The present invention provides a 2D FeB nanozyme prepared by a molten salt method, with a stoichiometric ratio of Fe to B of 1:1 and a complete two-dimensional sheet structure. This method has the advantages of high yield and low cost. Compared with the conventional high-temperature solid-state reaction method and chemical vapor deposition method, the preparation conditions of the present invention are simpler, the raw materials are easy to obtain, the repeatability is good, and the energy consumption is low. Due to the high yield, this method is suitable for large-scale production and has better application prospects. In addition, no harmful waste is generated during the preparation process, and the molten salt used can be reused with almost no waste generated, thus reducing the impact on the environment.

[0018] The 2D FeB nanozyme provided by the present invention has excellent physiological stability and has potential application prospects in exploring the enzyme-like activity of nanozymes, identifying natural antioxidants, evaluating the antioxidant capacity of foods, and in the field of environmental protection.

[0019] The present invention solves the problems of insufficient uniformity, stability, and activity performance of POD-like activity nanozymes in the prior art during the preparation process by optimizing the preparation method of two-dimensional iron boride nanozymes. Specifically, the present invention effectively improves the dispersibility and structural integrity of the materials during the reaction process by introducing an accurate mass ratio of iron oxide and boron powder and combining the auxiliary effects of NaCl and KCl flux. At the same time, the use of nanoscale powders and a strictly controlled grinding process ensures the full mixing of the reaction precursors, and the optimization of the microstructure of this material directly improves the catalytic performance of the obtained two-dimensional iron boride nanozyme.

[0020] During the preparation process, the present invention adopts an algorithm combining high-temperature calcination and atmosphere protection. By precisely controlling the heating rate (above 10 °C / min), the calcination temperature (780 °C to 1100 °C), and the holding time (5 to 120 minutes), an FeB nanozyme with a stable crystal phase and an ideal two-dimensional morphology is formed. The design of these process parameters enables the material to form a highly active exposed surface during the calcination process, significantly enhancing its POD-like activity. At the same time, by using a nitrogen or argon protective atmosphere, the occurrence of high-temperature oxidation is avoided, further improving the chemical stability and catalytic activity of the material.

[0021] In addition, in the post-treatment process of the present invention, through the combined process of high-speed centrifugation and alternating washing, the problems of impurity residue and insufficient product purity in the traditional method are solved. The alternating washing with hot water and ethanol removes by-products while ensuring the morphological integrity of the two-dimensional material. The final product exhibits high-efficient peroxidase-like activity, and significant technological progress has been achieved in terms of catalytic performance, stability, and application scope, providing high-quality functional materials for fields such as enzyme mimetic catalysis, antioxidant research, and biosensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of the preparation method of the 2D FeB nanozyme with peroxidase-like activity provided by the embodiment of the present invention.

[0023] Figure 2 It is a schematic diagram of the preparation of the 2D FeB nanozyme provided by the embodiment of the present invention.

[0024] Figure 3 It is the X-ray diffraction (XRD) pattern of the iron boride nanozyme provided by Example 1 of the present invention, and its corresponding crystal structure; the XRD results show that the prepared sample is FeB.

[0025] Figure 4 It is the scanning electron microscope (SEM), transmission electron microscope photo (TEM), high-resolution transmission electron microscope (HRTEM) photo, selected area electron diffraction (SAED) photo, and Mapping photo of the iron boride nanozyme provided by Example 1 of the present invention; it can be seen from the TEM results that the prepared FeB is a two-dimensional structure.

[0026] Figure 5 It is the XPS elemental fine spectra of Fe 2p and B 1s of the iron boride nanozyme provided by Example 1 of the present invention.

[0027] Figure 6 It is the test result graph of using ultraviolet absorption spectroscopy (UV) to test the scavenging of ABTS +· and the scavenging of DPPH · of the iron boride nanozyme provided by Example 1 of the present invention.

[0028] Figure 7This is the schematic diagram of the color development principle of 3,3',5,5'-tetramethylbenzidine (TMB) provided in Example 1 of the present invention, the ultraviolet spectra of FeB + TMB, FeB + H2O2 + TMB, and Fe3O4 + H2O2 + TMB, the time-dependent graph of the POD-like activity of FeB, the concentration-dependent graph of the POD activity of FeB, the temperature-dependent graph of the POD activity of FeB, the pH-dependent graph of the POD activity of FeB, the Michaelis constant graph of the POD activity of FeB for H2O2 and TMB substrates respectively, and the electron spin resonance (ESR) spectrum of FeB catalyzing H2O2 to produce ·OH.

[0029] Figure 8 This is Mn provided in Example 1 of the present invention 2+ and Mg 2+ The promotion graph of the POD-like activity of FeB nanozyme.

[0030] Figure 9 This is the partial least squares discriminant analysis (OPLSDA) score graph and permutation test graph calculated using SIMCA software for the detection of natural antioxidants by the iron boride nanozyme provided in Example 1 of the present invention.

[0031] Figure 10 This is the evaluation graph of the antioxidant ability of different teas by the iron boride nanozyme provided in Example 1 of the present invention. Detailed implementation manners

[0032] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] As Figure 1 shown, the embodiment of the present invention provides a preparation method of a two-dimensional iron boride nanozyme with POD-like activity, including the following steps:

[0034] Step 1: Weigh a certain amount of ferric oxide powder, boron powder, sodium chloride, and potassium chloride, and mix and grind them;

[0035] Step 2: Transfer the ground powder to an appropriate container, and under a protective atmosphere, perform high-temperature calcination treatment, and then cool the sample after high-temperature calcination naturally or under controlled conditions;

[0036] Step 3: Centrifuge and wash the product after high-temperature calcination, and use the method of alternating washing with water and ethanol, and then place the washed product in a vacuum drying oven for drying to obtain a 2D FeB nanozyme sample.

[0037] The key to preparing two-dimensional iron boride nanozymes with peroxidase-like activity lies in the selection of raw materials and their uniform mixing. As the iron source, iron oxide powder has good chemical activity; boron powder provides boron elements for the boronization reaction; sodium chloride and potassium chloride, as reaction assistants, mainly act as molten salt media. After weighing these materials in a specific ratio, they are mixed and ground. The introduction of mechanical energy promotes the uniform mixing of the materials and enhances the activity of the interfacial reaction, ensuring the reaction efficiency of subsequent high-temperature calcination.

[0038] The mixed powder is subjected to high-temperature calcination under a protective atmosphere of an inert gas (such as argon or nitrogen). During the calcination process, boron powder reacts chemically with iron oxide to form a two-dimensional FeB nanostructure. The molten salt (sodium chloride and potassium chloride) melts at high temperature, acting as a reaction medium to lower the reaction energy barrier and promote the growth of FeB crystals in the two-dimensional direction. At the same time, the use of a protective atmosphere effectively prevents the oxidation of iron and boron, providing favorable conditions for the formation of high-purity FeB nanozymes. After calcination, through natural or controlled cooling, the sample gradually forms a stable two-dimensional structure, avoiding lattice defects caused by thermal stress.

[0039] The product after high-temperature calcination contains unreacted raw materials and molten salt media, which need to be separated and purified by centrifugal washing. The method of alternating washing with water and ethanol is adopted. Water is mainly used to dissolve water-soluble impurities such as sodium chloride and potassium chloride, while ethanol can further remove organic or water-insoluble impurities and reduce the agglomeration of nanoparticles. Through multiple centrifugal washings, the surface of the product is ensured to be clean, improving the activity and stability of the nanozyme.

[0040] The washed product is placed in a vacuum drying oven and dried at low temperature or constant temperature. The vacuum environment can accelerate the volatilization of water and residual solvents, avoiding the agglomeration or structural damage of nanoparticles caused by high-temperature drying. The product after drying is a two-dimensional iron boride nanozyme sample with peroxidase-like activity. Its two-dimensional structure provides a large specific surface area, which can significantly improve the catalytic performance of the enzyme, especially showing significant advantages in mimicking peroxidase activity.

[0041] Through the above steps, the present invention realizes the efficient preparation of two-dimensional FeB nanozymes. Their unique two-dimensional structure and excellent peroxidase-like activity provide an innovative material basis and technical support for fields such as biocatalysis, antioxidant applications, and disease diagnosis.

[0042] Example 1

[0043] Preparation of two-dimensional iron boride nanozymes:

[0044] Take 0.15 g of nano-sized iron oxide powder, 0.25 g of boron powder, 2 g of sodium chloride, and 2 g of potassium chloride and place them in an agate mortar. Grind for more than 10 minutes until the grinding is sufficient and there is no sense of granulation. Load the obtained powder into a porcelain boat.

[0045] Under a nitrogen protection atmosphere, use a tube furnace to raise the temperature to 830 °C at a heating rate of 10 °C per minute, and maintain the temperature at this level for 1 h, then let it cool naturally. After the calcination is completed, wash the product by centrifugation, and alternately wash it with hot water at 80 °C and ethanol. Finally, place the washed product in a vacuum drying oven and dry it at 60 °C for 8 hours to obtain the final 2D FeB nanozyme product. The schematic diagram of the preparation of 2D FeB nanozyme is as Figure 2 shown. The ratio of Fe and B atoms of the obtained 2D FeB nanozyme is 1:1 ( Figure 3 ), and it exhibits an ultrathin two-dimensional morphology and a uniform distribution of Fe and B ( Figure 4 ). In addition, the 2D FeB nanozyme contains peaks of zero-valent Fe-B, peaks of oxidized Fe (Fe 2+ , Fe 3+ ), contains elemental B, peaks of B connected to Fe, and peaks of oxidized B ( Figure 5 ).

[0046] Antioxidant performance of boride nanosheets:

[0047] After preparing the boride nanosheets according to the above method, use UV to explore their scavenging efficiency for ABTS +· and DPPH · .

[0048] ABTS +· scavenging: Use UV to test the scavenging of ABTS +· , use potassium persulfate as an oxidant to obtain a large amount of ABTS +· free radicals. The preparation method is as follows: Dissolve 0.0374 g of ABTS powder in 30 mL of deionized water, and add 0.0066 g of K2S2O8 while stirring. React in the dark for 12 h. To test the reduction of ABTS +· , dilute the ABTS +· stock solution by 20 times, take 3 mL of the diluted ABTS +· and add it to a cuvette, then add the sample. Use a UV-visible spectrophotometer to record the characteristic absorption spectrum of ABTS +· at 734 nm. The test results show that FeB has good ABTS +· scavenging activity, and the activity increases with the increase of the FeB concentration ( Figure 6 a).

[0049] DPPH · Clearance: The DPPH was tested using ultraviolet absorption spectroscopy. · Reduction: 2.5 mL of 0.1 mg / mL DPPH ethanol solution was mixed with 0.5 mL of deionized water and added to a cuvette. Then the sample was added, and the characteristic absorption spectrum at 532 nm was recorded using a UV-visible spectrophotometer. The test results showed that FeB had good DPPH · scavenging activity, and the activity increased with the increase in the concentration of FeB ( Figure 6 b).

[0050] Pro-oxidant performance of boride nanosheets:

[0051] POD-like activity test: The POD-like activity of iron boride nanozyme was determined using ultraviolet absorption spectroscopy, and its activity performance under different temperature, time, concentration and pH conditions was studied. In addition, the POD-like activity of iron boride nanozyme was compared and analyzed with that of nano-ferroferric oxide. In the experiment, FeB catalyzed the decomposition of H2O2 to generate reactive oxygen species, which oxidized TMB to oxidized TMB (oxTMB), producing two characteristic absorption peaks at 370 nm and 652 nm in the UV spectrum. The test system consisted of 40 μL of 20 mM TMB, 40 μL of 0.1 M H2O2, 3 mL of water and an appropriate amount of sample. By monitoring the absorption intensity of the characteristic absorption peak of oxidized oxTMB at 652 nm, the POD-like activity of the sample was evaluated ( Figure 7 c). The results showed that with the prolongation of the reaction time, the intensity of the oxTMB characteristic absorption peak at 652 nm gradually increased, indicating that TMB was gradually oxidized, thus confirming that FeB had good POD activity.

[0052] Concentration-dependent POD-like test: The above test system further changed the sample concentration, and it was found that the POD-like activity of FeB increased with the increase in the sample addition amount, indicating that its POD-like activity was positively correlated with the FeB concentration ( Figure 7 d).

[0053] Temperature-dependent POD-like test: The POD-like activity of FeB was tested at different temperatures. The test system consisted of 40 μL of 20 mM TMB, 40 μL of 0.1 M H2O2, 3 mL of water and an appropriate amount of sample, and different temperature points were set in the range of 5 - 40 °C by a thermostat. The results showed that in the temperature range of 5 - 40 °C, the POD-like activity of FeB increased with the increase in the reaction temperature ( Figure 7 e).

[0054] pH-dependent POD-like test: The test was carried out by adjusting the pH value. The system consisted of 40 μL of 20 mM TMB, 40 μL of 0.1 M H2O2, 3 mL of sodium acetate-acetic acid (NaAc-HAc) buffer solution and an appropriate amount of sample. The results showed that as the pH value of the buffer solution decreased, the POD activity of FeB gradually increased, reached the maximum value at about pH = 3.8 and then began to decline( Figure 7 f).

[0055] To determine the Michaelis constant of the POD-like activity of 2D FeB nanozyme, the UV-visible spectroscopy kinetic measurement mode was adopted, and Origin software was used to linearly fit the data of the first 30 seconds to obtain the slope in the stage of the maximum reaction rate. The maximum reaction rate was calculated according to the Lambert-Beer law of absorbance, and enzyme kinetics fitting was carried out to obtain the maximum reaction rate and Michaelis constant of FeB at different substrate concentrations. There were two test systems. The first one: different concentrations of TMB, 20 μL of 0.1 M H2O2, 3 mL of water and 20 μL of 5 mg / mL FeB. The second one: 20 μL of 20 mM TMB, different concentrations of H2O2, 3 mL of water and 20 μL of 5 mg / mL FeB. The results showed that the Michaelis constant (K m ) of FeB for the substrate TMB was 0.344827 mM, and the Michaelis constant for the substrate H2O2 was 0.07973 mM. The Michaelis constant for the substrate H2O2 was lower, indicating that FeB had a higher affinity for H2O2( Figure 7 g and Figure 7 h).

[0056] To determine the types of reactive oxygen species generated by the reaction of FeB catalyzing H2O2, electron paramagnetic resonance spectroscopy (ESR) was used for determination. Hydroxyl radicals (·OH) can be captured by DMPO to form an adduct, which has a specific spectral signal in ESR. The reaction system consisted of 50 μL of solution, including 10 μL of 10 mM H2O2, 5 μL of 50 mM DMPO, 30 μL of H2O and 5 μL of sample, and the test was carried out with or without iron boride. The ESR spectral signals at different time points were recorded. The ESR instrument was set with a 20 dB microwave power attenuation, 1 G field modulation, 100 G scanning range and 2 mW microwave power. The results showed that compared with the blank group, the signals in the sample group showed spectral signals belonging to ·OH with the addition of the sample, confirming that the reactive oxygen species generated by FeB catalyzing H2O2 in the system were hydroxyl radicals( Figure 7 i).

[0057] Promotion of POD activity of FeB nanozyme by metal ions:

[0058] In this study, ultraviolet absorption spectroscopy was used to evaluate the effect of metal ions on the peroxidase-like activity of two-dimensional iron boride nanozymes. In the experiment, the test system contained 40 μL of 20 mM TMB, 40 μL of 0.1 M H2O2, 10 μL of 1 mM metal ion solution, 3 mL of water, and an appropriate amount of FeB sample. By monitoring the intensity of the characteristic absorption peak of oxidized oxTMB at a wavelength of 652 nm, we evaluated the effect of metal ions on the peroxidase-like activity of FeB. The experimental results showed that both Mn2+ and Mg2+ could enhance the POD activity of FeB, and the promoting effect of Mg2+ was more significant( Figure 8 )

[0059] Detection of natural antioxidants by FeB through peroxidase-like activity:

[0060] The present invention utilizes the peroxidase-like activity of two-dimensional FeB nanozymes to detect natural antioxidants. Through ultraviolet absorption spectroscopy, the application of the POD activity of FeB in detecting natural antioxidant substances was studied. In a specific experiment, two test systems were constructed: Test system 1 contained 20 μL of 20 mM TMB, 20 μL of 0.1 M H2O2, 3 mL of water, and 20 μL of 5 mg / mL FeB; Test system 2 additionally added 10 μL of 1 mM MgSO4 solution on the basis of system 1. Through these two test systems, the absorption peak intensities of different natural antioxidants at a wavelength of 652 nm were measured within 3 minutes of reaction time. Subsequently, the obtained data were sorted out, and partial least squares discriminant analysis (OPLS-DA) was performed using SIMCA software to generate an OPLS-DA score plot( Figure 9 a). In addition, the model was tested to ensure the accuracy of the data analysis results and confirm that the model did not have overfitting( Figure 9 b)

[0061] Evaluation of the antioxidant capacity of tea by FeB through peroxidase-like activity:

[0062] The present invention also provides a method for evaluating the antioxidant capacity of tea by using the peroxidase-like activity of two-dimensional FeB nanozymes. This method adopts ultraviolet absorption spectroscopy technology to evaluate the antioxidant performance of different types of tea through the POD activity of FeB. In the experiment, first, equal masses of different types of tea were soaked in boiling water, and after the water temperature cooled down, the supernatant was taken out as the tea water sample. The test system consisted of the following components: 20 μL of 20 mM TMB, 20 μL of 0.1 M H2O2, 2.9 mL of water, 20 μL of 5 mg / mL FeB solution, and 100 μL of the tea water sample. By comparing the absorption peak intensities of each sample at a wavelength of 652 nm after a 2-minute reaction time, the antioxidant capacities of different teas were evaluated. The experimental results showed that among all the tested teas, Maojian tea and jasmine tea exhibited the strongest antioxidant activity, while the antioxidant capacity of oolong tea was relatively weak( Figure 10 )

[0063] Example 2

[0064] Take 0.15 g of nano-ferroferric oxide powder, 0.25 g of boron powder, and 4 g of potassium chloride and place them in an agate mortar. Grind for more than 10 min until it is thoroughly ground without a granular feeling, and put the obtained powder into a porcelain boat.

[0065] Under a nitrogen protection atmosphere, use a tube furnace to raise the temperature to 830 °C at a heating rate of 10 °C per minute, and maintain the temperature at this temperature for 1 hour, and then let it cool naturally. After the calcination is completed, wash the product by centrifugation and washing, and alternately wash it with hot water at 80 °C and ethanol. Finally, put the washed product into a vacuum drying oven and dry it at 60 °C for 8 hours to obtain the final product.

[0066] Example 3

[0067] Take 0.15 g of nano-ferroferric oxide powder, 0.25 g of boron powder, and 4 g of sodium chloride and place them in an agate mortar. Grind for more than 10 min until it is thoroughly ground without a granular feeling, and put the obtained powder into a porcelain boat.

[0068] Under a nitrogen protection atmosphere, use a tube furnace to raise the temperature to 830 °C at a heating rate of 10 °C per minute, and maintain the temperature at this temperature for 1 hour, and then let it cool naturally. After the calcination is completed, wash the product by centrifugation and washing, and alternately wash it with hot water at 80 °C and ethanol. Finally, put the washed product into a vacuum drying oven and dry it at 60 °C for 8 hours to obtain the final product.

[0069] Example 4

[0070] Take 0.15 g of nano-ferroferric oxide powder, 0.25 g of boron powder, 2 g of sodium chloride, and 2 g of potassium chloride and place them in an agate mortar. Grind for more than 10 minutes until it is thoroughly ground without a granular feeling, and put the obtained powder into a porcelain boat.

[0071] Under a nitrogen protection atmosphere, use a tube furnace to raise the temperature to 900 °C at a heating rate of 10 °C per minute, and hold at this temperature for 1 hour, and then let it cool naturally. After the calcination is completed, wash the product by centrifugal washing, and alternately wash it with hot water at 80 °C and ethanol. Finally, put the washed product into a vacuum drying oven and dry it at 60 °C for 8 hours to obtain the final product.

[0072] Example 5

[0073] Take 0.15 g of nano-ferroferric oxide powder, 0.25 g of boron powder, 2 g of sodium chloride, and 2 g of potassium chloride and place them in an agate mortar. Grind for more than 10 minutes until it is thoroughly ground without a granular feeling, and put the obtained powder into a porcelain boat.

[0074] Under a nitrogen protection atmosphere, use a tube furnace to raise the temperature to 950 °C at a heating rate of 10 °C per minute, and hold at this temperature for 1 hour, and then let it cool naturally. After the calcination is completed, wash the product by centrifugal washing, and alternately wash it with hot water at 80 °C and ethanol. Finally, put the washed product into a vacuum drying oven and dry it at 60 °C for 8 hours to obtain the final product.

[0075] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be covered by the protection scope of the present invention.

Claims

1. A preparation method of a two-dimensional iron boride nanozyme with peroxidase-like activity, characterized in that, It includes the following steps: Step 1: Weigh a certain amount of iron tetroxide powder, boron powder, sodium chloride, and potassium chloride, and mix and grind them; Step 2: Transfer the ground powder to an appropriate container, and under a protective atmosphere, conduct high-temperature calcination treatment, and then cool the sample after high-temperature calcination naturally or under controlled conditions; Step 3: Centrifuge and wash the product after high-temperature calcination, using the method of alternating washing with water and ethanol, and then place the washed product in a vacuum drying oven for drying to obtain a 2D FeB nanozyme sample.

2. The preparation method of the two-dimensional iron boride nanozyme with POD-like activity according to claim 1, wherein, In Step 1, the iron tetroxide is a nano-scale powder with a particle size less than 20 μm; the particle size of the boron powder is 10-20 μm.

3. The preparation method of the two-dimensional iron boride nanozyme with POD-like activity according to claim 1, characterized in that, In Step 1, the iron tetroxide powder, boron powder, sodium chloride, and potassium chloride are placed together in an agate mortar for mixing and grinding; grind in the agate mortar for 10 min to 1 h.

4. The preparation method of the two-dimensional iron boride nanozyme with POD-like activity according to claim 1, characterized in that, In Step 1, the mass ratio of iron tetroxide, boron powder, NaCl, and KCl is 1-6:3-7:0-50:0-50, where NaCl and KCl cannot be 0 at the same time.

5. The preparation method of the two-dimensional iron boride nanozyme with POD-like activity according to claim 1, characterized in that, In Step 2, the powder is calcined using a tube furnace under a nitrogen or argon atmosphere; the tube furnace calcination heats up to 780°C - 1100°C at a rate of more than 10°C / min, then holds at this temperature for 5 - 120 minutes, and then cools down naturally.

6. The preparation method of the two-dimensional iron boride nanozyme with POD-like activity according to claim 1, characterized in that, In Step 3, the centrifuge washing speed is 8000 r / min - 12000 r / min, and it is washed alternately with water and ethanol more than three times, and the last wash uses ethanol, and the temperature of the water is 80°C - 100°C.

7. The preparation method of the two-dimensional iron boride nanozyme with POD-like activity according to claim 1, characterized in that In Step 3, the obtained product is placed in a vacuum drying oven and vacuum dried continuously at 60°C for 8 hours to finally obtain a 2D FeB nanozyme product.

8. A two-dimensional iron boride nanozyme with peroxidase-like activity prepared by the preparation method of the two-dimensional iron boride nanozyme with peroxidase-like activity according to any one of claims 1-7, characterized in that, The two-dimensional iron boride nanozyme has a complete two-dimensional planar structure, and the atomic ratio of Fe / B in 2D FeB is 1:

1.

9. Application of a two-dimensional iron boride nanozyme with POD-like activity as described in Claim 8 in detecting natural antioxidants.

10. Application of a two-dimensional iron boride nanozyme with POD-like activity as described in Claim 8 in evaluating the antioxidant activities of different teas.

Images