Fe monatomic / Pt nanocluster nanoenzyme as well as preparation method and application thereof

Abstract

The invention relates to the technical field of nano-enzymes, in particular to a Fe monatomic / Pt nano-cluster nano-enzyme as well as a preparation method and application thereof. The invention relates to a preparation method of Fe monatomic / Pt nanocluster nano-enzyme, which comprises the following steps: dispersing graphite phase carbon nitride in water, adding polyphenol and amine, stirring for 10-14 hours, carrying out suction filtration, and drying to obtain a polyphenol amine coated graphite phase carbon nitride precursor; dispersing the graphite-phase carbon nitride precursor in water, adding an iron source and a platinum source, stirring for 10-14 hours, and performing suction filtration, drying, carbonization, acid pickling, centrifugation and drying to obtain the Fe monatomic / Pt nanocluster nanoenzyme. The Fe monatomic / Pt nanocluster nano-enzyme is prepared by the method disclosed by the invention. The invention relates to an application of a Fe monatomic / Pt nanocluster nano-enzyme in pesticide detection. Compared with a single Fe monatomic or Pt nanocluster nano-enzyme, the Fe monatomic / Pt nanocluster nano-enzyme provided by the invention can generate a synergistic effect and has higher catalytic activity.

Description

Technical Field

[0001] The present application relates to the field of nanozyme technology, and in particular to an Fe single atom / Pt nanocluster nanozyme and its preparation method and application. Background Art

[0002] Since the discovery in 2007 of peroxidase-like activity in ferroferric oxide nanoparticles, nanozymes have shown significant potential in biosensing due to their high stability and low cost. Nanozymes, a product of the integration of nanotechnology and enzymology, have gradually attracted attention. Nanozymes are nanomaterials with enzyme-like catalytic activity. Their unique physicochemical properties enable them to exhibit similar or even superior performance in catalytic reactions to natural enzymes. Compared with natural enzymes, nanozymes offer many significant advantages, including low cost, relatively simple preparation processes, and large-scale production. They are also highly stable, maintaining strong catalytic activity under extreme conditions such as high temperatures, a wide pH range, and organic solvents, and are not susceptible to inactivation. Their catalytic activity can be manipulated and optimized through various approaches, including adjusting the composition, structure, size, and surface modification of the nanomaterials, to meet diverse detection needs. However, the catalytic activity of traditional nanozymes (such as metal oxides and carbon-based materials) is far lower than that of natural enzymes (such as HRP), primarily due to low active site density, low atom utilization, and a lack of cooperative catalytic mechanisms. Single-atom nanozymes offer the possibility of achieving efficient enzyme-like catalytic activity, but a single active site is difficult to drive complex chemical reaction processes. Therefore, coupling single-atom sites with other sites can significantly enhance the catalytic activity of nanozymes and can drive more complex chemical reactions. Fe single atoms have a unique electronic structure and high specific activity. Dispersing them on a carrier in the form of single atoms can maximize the utilization of active sites and improve catalytic efficiency. Pt nanoclusters have good conductivity and excellent catalytic properties, and exhibit low activation energy and high reaction rates in many chemical reactions. Combining Fe single atoms with Pt nanoclusters to construct nanozymes is expected to achieve complementary advantages through the synergistic effect between the two, and to prepare nanozyme materials with higher catalytic activity and selectivity.

[0003] At present, there are no public reports of composite nanozymes containing both iron single atoms and platinum nanoclusters. This combination may produce a synergistic effect, but its realization requires overcoming challenges such as structural control and stability. For example, if the Fe single atom and the Pt nanocluster are far apart, the two can only play a catalytic role separately and cannot work together. Although with the help of a carrier, the two can be evenly distributed and the distance between them can be shortened. However, it is difficult to find a suitable carrier that can combine the two particles and make them evenly distributed, which affects the synergistic effect of the two.

[0004] For example, single atoms generally have a greater catalytic effect than nanoclusters, which in turn are greater than nanoparticles. The particle sizes of the three are: single atoms are smaller than nanoclusters, which are smaller than nanoparticles. Platinum (Pt) is prone to atomic migration and has a very high surface energy. This results in the formation of Pt nanoparticles rather than Pt nanoclusters during the preparation process, thus reducing its catalytic effect. Summary of the Invention

[0005] In view of this, the present application provides a synergistic Fe single atom / Pt nanocluster nanozyme.

[0006] It is also necessary to provide a method for preparing Fe single atom / Pt nanocluster nanozymes.

[0007] It is also necessary to provide an application of Fe single atom / Pt nanocluster nanozyme in pesticide detection.

[0008] A method for preparing Fe single atom / Pt nanocluster nanozyme, comprising the following steps: Step S1: dispersing graphite carbon nitride in water, adding polyphenol and amine, stirring for 10 to 14 hours, filtering and drying to obtain a polyphenol-amine-coated graphite carbon nitride precursor; Step S2: Disperse the graphite phase carbon nitride precursor in water, add iron source and platinum source, stir for 10 to 14 hours, filter, dry, carbonize, acid wash, centrifuge, and dry to obtain Fe single atom / Pt nanocluster nanozyme.

[0009] An Fe single atom / Pt nanocluster nanozyme is prepared by the above method.

[0010] Application of Fe single atom / Pt nanocluster nanozyme in pesticide detection.

[0011] The technical effect of this application is that the Fe single atom / Pt nanocluster nanozyme of this application is microscopically flaky, which has a larger specific surface area than spherical nanozymes and more complete contact with reactants, thereby producing a better catalytic effect. Compared with single Fe single atom or Pt nanocluster nanozymes, the Fe single atom / Pt nanocluster nanozymes of this application can produce synergistic effects and have higher catalytic activity.

[0012] The preparation method of the Fe single-atom / Pt nanocluster nanozyme disclosed herein involves first coating polyphenolamine on a sheet of carbon nitride, then fixing iron and platinum ions to form a complex with the polyphenolamine. Upon heating, the iron and platinum ions undergo a reduction reaction and the polyphenolamine undergoes thermal decomposition, chemically fixing the iron single atoms and Pt nanoclusters to the sheet carrier. This loading method can better control the distribution of the iron single atoms and platinum nanoclusters, making them more uniform and more stable.

[0013] The preparation method of the Fe single atom / Pt nanocluster nanozyme of the present application can fix Pt in the form of nanoclusters on a sheet carrier. During the entire process, Pt does not aggregate into nanoparticles, and the catalytic effect is better.

[0014] The Fe single atom / Pt nanocluster nanozyme of the present application can be used for rapid detection of pesticide residues. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the TEM image of the Fe single-atom nanozyme of Example 1; Figure 2 This is the TEM image of the Pt nanocluster nanozyme of Example 2; Figure 3 This is the TEM image of the Fe single atom / Pt nanocluster nanozyme of Example 3; Figure 4 is the atomic phase diagram of Example 1; Figure 5 This is the atomic phase diagram of Example 2; Figure 6 is the atomic phase diagram of Example 3; Figure 7 is the peroxidase-like activity diagram of the nanozyme; Figure 8 This is the radar image of Fe single atom / Pt nanocluster nanozyme detecting chlorpyrifos; Figure 9 This is the radar diagram of Fe single-atom nanozyme and Pt nanocluster nanozyme detecting chlorpyrifos; DETAILED DESCRIPTION

[0016] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0017] A method for preparing Fe single atom / Pt nanocluster nanozyme, comprising the following steps: Step S1: dispersing graphite carbon nitride in water, adding polyphenol and amine, stirring for 10 to 14 hours, filtering and drying to obtain a polyphenol-amine-coated graphite carbon nitride precursor; The polyphenol and amine react to form polyphenolamine, which is then coated on the graphite carbon nitride precursor after sufficient stirring.

[0018] In a preferred embodiment, the polyphenol is selected from one or more of 1,3,5-benzenetriol, 1,2,3-benzenetriol, 1,2,4-benzenetriol, 1,4-benzenediol, and 1,2-benzenediol. Polyphenols are rich in hydroxyl functional groups and self-assemble under the action of organic amines and are coated on the surface of the graphitic carbon nitride template. These abundant functional groups can effectively anchor metal ions to form complexes.

[0019] More preferably, the polyphenol is 1,3,5-benzimidazole.

[0020] In a preferred embodiment, the amine is ethylenediamine.

[0021] In a preferred embodiment, the mass volume ratio of the graphite phase carbon nitride, 1,3,5-benzenetriol, ethylenediamine, and water is 0.10-0.30 g: 0.15-0.35 g: 0.2-0.5 mL: 100 mL.

[0022] More preferably, the mass volume ratio of the graphite phase carbon nitride, 1,3,5-benzenetriphenol, ethylenediamine, and water is 0.1 g: 0.2 g: 0.3 mL: 100 mL.

[0023] Step S2: Disperse the graphite phase carbon nitride precursor in water, add iron source and platinum source, stir for 10 to 14 hours, filter, dry, carbonize, acid wash, centrifuge, and dry to obtain Fe single atom / Pt nanocluster nanozyme.

[0024] The iron and platinum sources react with polyphenolamine to form a complex. After sufficient stirring, the iron and platinum sources bind to the polyphenolamine in the form of a complex. Because graphitic carbon nitride has a flaky structure and a large specific surface area, the iron and platinum sources are able to fully contact the polyphenolamine and rapidly complex. This means that the polyphenolamine can quickly capture the iron and platinum, distributing them more evenly across the flaky structure. After carbonization, the platinum atoms are further apart, and chemically bonded to the flaky structure, making atomic migration less likely. This allows for the formation of a stable nanocluster structure.

[0025] At the same time, since the distribution uniformity of iron and platinum is improved, the synergistic effect of iron and platinum will be better, which is more conducive to the catalysis of substances.

[0026] In a preferred embodiment, the iron source is selected from one or more of ferric chloride, ferric nitrate, ferric acetylacetonate, ferric sulfate, ferric citrate, and ferrous chloride.

[0027] More preferably, the iron source is ferric chloride.

[0028] In a preferred embodiment, the platinum source is selected from one or more of chloroplatinic acid, potassium chloroplatinate, potassium chloroplatinite, sodium hexachloroplatinate, platinum tetrachloride, platinum dichloride, platinum nitrate, and platinum sulfite.

[0029] More preferably, the platinum source is chloroplatinic acid.

[0030] In a preferred embodiment, the mass volume ratio of the polyphenolamine-coated graphite-phase carbon nitride precursor, the iron source, the platinum source, and water is 0.10-0.30 g: 0-0.4 mmol / L: 0-1 mmol / L: 100 mL.

[0031] More preferably, the mass volume ratio of the polyphenol-coated graphite-phase carbon nitride precursor, iron source, platinum source, and water is 0.10 g: 0.04 mmol / L: 0.1 mmol / L: 100 mL.

[0032] In a preferred embodiment, the carbonization process for preparing the Fe single atom / Pt nanocluster nanozyme is carried out in a nitrogen atmosphere at a carbonization temperature of 700-900° C. At this temperature, a Fe single atom / Pt nanocluster nanozyme with a stable structure can be obtained.

[0033] In a preferred embodiment, the carbonization heating rate of the present application is 2-10°C / min; and the carbonization time is 1-4h.

[0034] In a preferred embodiment, the pickling of the present application uses a 2-5 mol / L hydrochloric acid solution.

[0035] In a preferred embodiment, the centrifugation condition of the present application is 10000-12000 rpm for 5-15 min.

[0036] In a preferred embodiment, the washing conditions are washing with water 3-5 times, and then washing with anhydrous ethanol 3-5 times.

[0037] An Fe single atom / Pt nanocluster nanozyme is prepared by the above method.

[0038] Application of the above-mentioned Fe single atom / Pt nanocluster nanozyme in pesticide detection.

[0039] In a preferred embodiment, the aforementioned Fe single-atom / Pt nanocluster nanozyme is used to detect pesticides via colorimetry. Compared to Fe single-atom or Pt nanocluster nanozymes, the Fe single-atom and Pt nanocluster nanozymes of this application exhibit synergistic effects, resulting in superior pesticide detection. This approach is illustrated below with reference to the following examples.

[0040] Example 1: Preparation of Fe single-atom nanozymes (1) Accurately weigh 0.1 g of graphite carbon nitride powder and 0.2 g of 1,3,5-benzenetriol in 100 mL of water and ultrasonicate until fully dispersed. After magnetic stirring for 30 minutes, add 0.3 mL of ethylenediamine. After reacting for 6 hours, filter and vacuum dry to obtain a solid product.

[0041] (2) Accurately weigh 0.1 g of solid product 1, disperse it in 100 mL of deionized water, add 1.1 mg of ferric chloride hexahydrate, stir for 12 h, filter, and vacuum dry for 24 h to obtain solid product 2.

[0042] (3) The solid product 2 was placed in a tubular furnace, calcined and carbonized at 800 °C under a nitrogen atmosphere, and then acid-washed with a 2 mol / L hydrochloric acid solution. After centrifugation and drying, the Fe single-atom nanozyme was obtained.

[0043] Example 2: Preparation of Pt nanocluster nanozymes (1) Accurately weigh 0.1 g of graphite carbon nitride powder and 0.2 g of 1,3,5-benzenetriol in 100 mL of water and ultrasonicate until fully dispersed. After magnetic stirring for 30 minutes, add 0.3 mL of ethylenediamine. After reacting for 6 hours, filter and vacuum dry to obtain a solid product.

[0044] (2) Accurately weigh 0.1 g of solid product 1, disperse it in 100 mL of deionized water, add 5.2 mg of chloroplatinic acid hexahydrate, stir for 12 h, filter, and vacuum dry for 24 h to obtain solid product 2.

[0045] (3) The solid product 3 was placed in a tube furnace, calcined and carbonized at 800 °C under a nitrogen atmosphere, and then acid-washed with a 2 mol / L hydrochloric acid solution. After centrifugation and drying, the Pt nanocluster nanozyme was obtained.

[0046] Example 3: Preparation of Fe single atom / Pt nanocluster nanozymes (1) Accurately weigh 0.1 g of graphite carbon nitride powder and 0.2 g of 1,3,5-benzenetriol in 100 mL of water and ultrasonicate until fully dispersed. After magnetic stirring for 30 minutes, add 0.3 mL of ethylenediamine. After reacting for 6 hours, filter and vacuum dry to obtain a solid product.

[0047] (2) Accurately weigh 0.1 g of solid product 1, disperse it in 100 mL of deionized water, add 5.2 mg of chloroplatinum hexahydrate and 1.1 mg of ferric chloride hexahydrate, stir for 12 h, filter, and vacuum dry for 24 h to obtain solid product 2.

[0048] (3) The solid product 2 was placed in a tubular furnace, calcined and carbonized at 800 °C under a nitrogen atmosphere, and then acid-washed with a 2 mol / L hydrochloric acid solution. After centrifugation and drying, the Fe single atom / Pt nanocluster nanozyme was obtained.

[0049] The nanozymes prepared in Examples 1 to 3 were subjected to TEM testing, and the results were as follows: Figures 1-3 As shown in the figure, the prepared nanozymes all have a lamellar structure.

[0050] AC HAADF-STEM was performed on the nanozymes prepared in Examples 1 to 3, and the results were as follows: Figures 4-6 As shown in Figure 3, Fe exists as a single atom with isolated Fe atomic sites. Pt mostly exists as clusters with a size of less than 2 nm. The Pt clusters are relatively dispersed, indicating that few Pt nanoparticles are present during the preparation process.

[0051] In the above three embodiments, the nanozymes exhibit peroxidase-like activity, such as Figure 7 , which catalyzes the substrate (H2O2) to produce reactive oxygen species (·OH), which reacts with TMB to form oxTMB, producing a blue reaction. Using a UV-visible spectrophotometer to measure absorbance at 652nm, the concentration of oxTMB can be determined, which can then be compared to peroxidase-like activity. Based on this information, pesticide detection can be performed using colorimetry. The specific process is as follows: The nanozyme was prepared into a 0.2 mg / mL solution for later use.

[0052] Prepare a 10 mM solution of 3,3',5,5'-tetramethylbenzidine (TMB) powder with anhydrous ethanol.

[0053] Prepare 0.1 mol / L buffer solution (pH 4) by mixing acetic acid and sodium acetate and set aside.

[0054] Chlorpyrifos was prepared into a 3.3 mg / mL solution for later use.

[0055] 10 μL of 0.2 mg / mL nanozyme solution was evenly dispersed in 0.1 mol / L acetic acid-sodium acetate buffer solution to obtain a nanozyme buffer solution with a concentration of 0.6 μg / mL. Hydrogen peroxide and TMB were added to make the concentrations of the two in the nanozyme buffer solution 60 mM and 0.3 mM, respectively. Different concentrations of chlorpyrifos (0, 2, 4, 6, 8, 10 ppm) were added. After incubation at 25°C for 15 minutes, the absorbance value (A) was measured at a wavelength of 652 nm and compared with the absorbance value without pesticide (A0). The absorbance change value (∆A=(A0-A) / A0) was obtained, and a pesticide detection radar chart was drawn. The results are shown in Figure 2. Figure 8 and Figure 9As shown, after adding different concentrations of chlorpyrifos, the absorbance change value of the Fe single atom / Pt nanocluster nanozyme of the present application is significantly greater than the absorbance change value of the Fe single atom nanozyme or the Pt nanocluster nanozyme, which shows that the catalytic effect produced by the synergistic effect of the Fe single atom / Pt nanocluster nanozyme of the present application is significantly higher than the catalytic effect of a single Fe single atom nanozyme or Pt nanocluster nanozyme, and can be used for pesticide detection.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing Fe single atom / Pt nanocluster nanozyme, comprising the following steps: Step S1: dispersing graphite carbon nitride in water, adding polyphenol and amine, stirring for 10 to 14 hours, filtering and drying to obtain a polyphenol-amine-coated graphite carbon nitride precursor; Step S2: Disperse the graphite phase carbon nitride precursor in water, add iron source and platinum source, stir for 10 to 14 hours, filter, dry, carbonize, acid wash, centrifuge, and dry to obtain Fe single atom / Pt nanocluster nanozyme.

2. The method for preparing the Fe single atom / Pt nanocluster nanozyme according to claim 1, wherein: In step S1, the polyphenol is selected from one or more of 1,3,5-benzenetriol, 1,2,3-benzenetriol, 1,2,4-benzenetriol, 1,4-benzenediol, and 1,2-benzenediol.

3. The method for preparing the Fe single atom / Pt nanocluster nanozyme according to claim 2, wherein: In step S1, the amine is ethylenediamine.

4. The method for preparing the Fe single atom / Pt nanocluster nanozyme according to claim 3, wherein: In step S1, the mass volume ratio of the graphite phase carbon nitride, 1,3,5-benzenetriol, ethylenediamine, and water is 0.10-0.30 g: 0.15-0.35 g: 0.2-0.5 mL: 100 mL.

5. The method for preparing the Fe single atom / Pt nanocluster nanozyme according to claim 1, wherein: In step S2, the iron source is selected from one or more of ferric chloride, ferric nitrate, ferric acetylacetonate, ferric sulfate, ferric citrate, and ferrous chloride.

6. The method for preparing the Fe single atom / Pt nanocluster nanozyme according to claim 1, wherein: In step S2, the platinum source is selected from one or more of chloroplatinic acid, potassium chloroplatinate, potassium chloroplatinite, sodium hexachloroplatinate, platinum tetrachloride, platinum dichloride, platinum nitrate, and platinum sulfite.

7. The method for preparing the Fe single atom / Pt nanocluster nanozyme according to claim 1, wherein: In step S2, the mass volume ratio of the polyphenolamine-coated graphite-phase carbon nitride precursor, the iron source, the platinum source, and water is 0.10 g: 0.04 mmol / L: 0.1 mmol / L: 100 mL.

8. The method for preparing the Fe single atom / Pt nanocluster nanozyme according to claim 1, wherein: In step S2, during the carbonization process of preparing Fe single atom / Pt nanocluster nanozyme, it is carried out in a nitrogen atmosphere, the carbonization temperature is 700~900℃, the carbonization heating rate is 2~10℃ / min; and the carbonization time is 1~4h.

9. An Fe single atom / Pt nanocluster nanozyme, prepared by the preparation method of the Fe single atom / Pt nanocluster nanozyme according to any one of claims 1 to 8.

10. Use of the Fe single atom / Pt nanocluster nanozyme as claimed in claim 9 in pesticide detection.

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