Monatomic modified two-dimensional piezoelectric nanosheet as well as preparation method and application thereof

Abstract

The invention discloses a monatomic modified two-dimensional piezoelectric nanosheet as well as a preparation method and application thereof, and relates to the field of nano materials. The preparation method comprises the following steps: carrying out acid etching treatment on a bismuth-based piezoelectric material to obtain an acid etching product; mixing with salt containing metal atoms, and calcining in an inert atmosphere to obtain a calcined product; and then carrying out ultrasonic stripping and polymer modification to obtain the monatomic modified two-dimensional piezoelectric nanosheet. Metal atoms are modified on the bismuth-based piezoelectric material through calcination treatment, the surface and structure of the bismuth-based piezoelectric material can be controlled, the specific surface area of the material can be increased, more adjustable active sites can be provided, the catalytic activity and selectivity of the bismuth-based piezoelectric material can be enhanced, and the bismuth-based piezoelectric material has high stability; meanwhile, the material size is reduced through acid etching treatment and ultrasonic stripping, the nanoscale two-dimensional piezoelectric nanosheet is prepared and is suitable for the field of catalytic degradation, disinfection and antibiosis or drug delivery products, and the preparation method is simple, free of pollution, low in cost and suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials, and more particularly to a single-atom modified two-dimensional piezoelectric nanosheet, its preparation method, and its application. Background Technology

[0002] Single-atom modified piezoelectric nanomaterials, compared to larger piezoelectric materials, possess a larger specific surface area and more tunable active sites, making them more likely to generate highly toxic reactive oxygen species (ROS) with tumor-killing effects. The single atoms on piezoelectric materials exhibit the highest atom utilization efficiency, thus enhancing their catalytic activity like natural enzymes. In addition to catalyzing ROS generation, single-atom catalysts demonstrate superior stability over a wider temperature range and at high ionic strengths compared to natural enzymes, a characteristic not possessed by most natural enzymes.

[0003] Bismuth-based piezoelectric materials, being Pb-free, avoid the toxicity risks to humans associated with traditional lead-based piezoelectric materials (such as PZT) and are widely used in catalytic degradation, disinfection and antibacterial applications, and drug delivery. 2D bismuth-based materials possess a highly anisotropic structure, characterized by alternating (Bi₂O₂) elements. 2+ The ordered layered structure, including the anion layer and the ion layer, is considered beneficial for the formation of an internal electric field, thereby achieving effective charge separation. In terms of catalytic degradation, 2D bismuth-based piezoelectric materials can decompose harmful substances using the generated hydroxyl radicals (·OH) under external stimuli. Under external influences, 2D bismuth-based piezoelectric materials can kill bacteria and viruses by generating active substances, achieving disinfection and antibacterial effects. The layered structure and large specific surface area of ​​2D bismuth-based piezoelectric materials can efficiently load chemotherapeutic drugs (such as doxorubicin), nucleic acids, or proteins for drug delivery.

[0004] Therefore, in order to achieve single-atom modification on 2D bismuth-based piezoelectric materials, it is necessary to study the preparation technology of single-atom modified 2D bismuth-based piezoelectric materials in order to control their surface and structure and thus improve the selectivity and activity of catalytic reactions. Summary of the Invention

[0005] This invention provides a single-atom modified two-dimensional piezoelectric nanosheet, its preparation method and application. This application uses single-atom modified bismuth-based piezoelectric materials to improve the activity and selectivity of catalytic reactions and to prepare nanoscale bismuth-based piezoelectric materials.

[0006] To address the aforementioned technical problems, one objective of this invention is to provide a method for preparing single-atom modified two-dimensional piezoelectric nanosheets, comprising the following steps:

[0007] (1) Acid etching treatment was performed on the bismuth-based piezoelectric material to obtain the acid etching product;

[0008] (2) The acid etching product is mixed with a salt containing metal atoms and calcined in an inert atmosphere to obtain a calcined product;

[0009] (3) The calcined product is subjected to ultrasonic exfoliation and polymer modification to obtain single-atom modified two-dimensional piezoelectric nanosheets.

[0010] This application employs calcination to modify bismuth-based piezoelectric materials with metal atoms, which increases the specific surface area of ​​the piezoelectric material, provides more tunable active sites, enhances its catalytic activity for reactive oxygen species generation, improves catalytic selectivity, and exhibits high stability. Simultaneously, acid etching is used to reduce the size of the bismuth-based piezoelectric material, and ultrasonic exfoliation is used to further reduce the material size, thus preparing nanoscale two-dimensional piezoelectric nanosheets. Finally, polymer modification is applied to the surface to improve the dispersibility of the nanomaterials. This bismuth-based piezoelectric material can be synthesized via a hydrothermal method, which is simple, pollution-free, and low-cost, making it suitable for industrial production.

[0011] As a preferred embodiment, in step (2), the metal atoms in the salt containing metal atoms are at least one of aluminum, cobalt, nickel, copper, zinc, iron, chromium, titanium, manganese, potassium, and zirconium.

[0012] As a preferred embodiment, in step (2), the salt containing metal atoms is acetylacetone salt.

[0013] As a preferred embodiment, in step (2), the molar ratio of the acid etching product to the salt containing metal atoms is (1.7-3.4):(0.09-0.4), preferably (3-3.1):(0.18-0.2).

[0014] This application controls the metal atom loading of the two-dimensional piezoelectric nanosheets within the above-mentioned range, which enables the two-dimensional piezoelectric nanosheets to have a better current response. Furthermore, the current response reaches its maximum when the amount of salt containing metal atoms is within the above-mentioned preferred range, and the greater the current response, the better the electron (e) content. - ) and holes (h + The higher the separation efficiency.

[0015] As a preferred embodiment, in step (1), the preparation method of the bismuth-based piezoelectric material includes the following steps: adding Bi source, Ti source and sodium oleate to an alkaline solution, mixing them evenly and then carrying out a hydrothermal reaction to obtain the bismuth-based piezoelectric material.

[0016] As a preferred embodiment, the bismuth-based piezoelectric material is Bi4Ti3O. 12 The bismuth-based piezoelectric material is micron-sized.

[0017] As a preferred embodiment, in the preparation method of the bismuth-based piezoelectric material, the Bi source is Bi(NO3)3·5H2O.

[0018] As a preferred embodiment, in the preparation method of the bismuth-based piezoelectric material, the Ti source is tetrabutyl titanate.

[0019] As a preferred embodiment, in the preparation method of the bismuth-based piezoelectric material, the molar ratio of the Bi source to the Ti source is (4-8):(3-7).

[0020] As a preferred embodiment, in the preparation method of the bismuth-based piezoelectric material, the molar ratio of sodium oleate, Bi source and Ti source is (1-2):(4-8):(3-7).

[0021] As a preferred embodiment, in the preparation method of the bismuth-based piezoelectric material, the molar ratio of the alkaline solution, sodium oleate, Bi source and Ti source is (200-400):(1-2):(4-8):(3-7).

[0022] As a preferred embodiment, in the preparation method of the bismuth-based piezoelectric material, the concentration of alkali in the alkaline solution is 3-8 mol / L.

[0023] As a preferred embodiment, in the preparation method of the bismuth-based piezoelectric material, the alkali in the alkaline solution is sodium hydroxide.

[0024] As a preferred embodiment, in the preparation method of the bismuth-based piezoelectric material, the hydrothermal reaction temperature is 160-220℃ and the time is 15-30h.

[0025] As a preferred embodiment, in the preparation method of the bismuth-based piezoelectric material, the mixing method is ultrasonic mixing for 10-20 min, followed by stirring for 30-120 min.

[0026] As a preferred option, in step (1), the acid used for acid etching is nitric acid.

[0027] As a preferred option, in step (1), the acid concentration of the acid etching treatment is 2-5 mol / L.

[0028] As a preferred option, in step (1), the acid etching process takes 10-15 hours.

[0029] As a preferred embodiment, in step (2), the inert atmosphere is at least one of nitrogen, helium, neon, and argon.

[0030] As a preferred option, in step (2), the calcination temperature is 280-320℃ and the calcination time is 1-5h.

[0031] As a preferred option, in step (3), the frequency of ultrasonic ablation is 300-500W and the time is 1-3h.

[0032] As a preferred embodiment, in step (3), the polymer modification is performed by adding sodium deoxycholate and water to the calcined product, wherein the mass ratio of the calcined product to sodium deoxycholate is 1:(0.5-2):(0.3-0.5).

[0033] To address the aforementioned technical problems, a second objective of this invention is to provide a method for preparing single-atom modified two-dimensional piezoelectric nanosheets using the aforementioned method.

[0034] To address the aforementioned technical problems, a third objective of this invention is to provide an application of single-atom modified two-dimensional piezoelectric nanosheets in the preparation of products for catalytic degradation, disinfection and antibacterial purposes, or drug delivery.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The bismuth-based piezoelectric material of this application can be synthesized by hydrothermal method. The metal atoms are modified on the bismuth-based piezoelectric material by calcination treatment to control its surface and structure, which can increase the specific surface area of ​​the piezoelectric material, provide more tunable active sites, enhance its catalytic activity and selectivity, and have high stability over a wide temperature range and at high ionic strength. It can be applied to the fields of catalytic degradation, disinfection and antibacterial or drug delivery.

[0037] 2. This application uses acid etching to treat micron-sized bismuth-based piezoelectric materials to reduce their size, and then further reduces the material size to the nanoscale by ultrasonic exfoliation. Finally, the surface is modified with polymers to improve the dispersibility of the nanomaterials and reduce agglomeration. This preparation method is simple, pollution-free and low-cost, and suitable for industrial production. Attached Figure Description

[0038] Figure 1 : XRD pattern of a single-atom modified two-dimensional piezoelectric nanosheet in Example 1 of this invention;

[0039] Figure 2 : This is a hydrated particle size diagram of the hydrothermal product of step (1) and the acid etching product of step (2) in Example 1 of the present invention;

[0040] Figure 3 : This is a hydrated particle size diagram of a single-atom modified two-dimensional piezoelectric nanosheet in Example 1 of the present invention;

[0041] Figure 4 : Acoustocurrent diagrams of copper atom-modified two-dimensional piezoelectric nanosheets in Examples 1-4 of this invention (Note: 25 - Example 2; 50 - Example 1; 75 - Example 3; 100 - Example 4);

[0042] Figure 5This is a diagram showing the catalytic experimental results of a single-atom modified two-dimensional piezoelectric nanosheet-like glutathione peroxidase in Example 1 of this invention.

[0043] Figure 6 : This is a diagram showing the catalytic experimental results of a two-dimensional piezoelectric nanosheet-like glutathione peroxidase in Comparative Example 1 of this invention;

[0044] Figure 7 : Hydrated particle size diagrams of a single-atom modified two-dimensional piezoelectric nanosheet in Example 1 and Comparative Examples 1-3 of the present invention (Note: Cu-BTO - Example 1; No acid etching - Comparative Example 2; No ultrasonic peeling - Comparative Example 3; No sodium deoxycholate modification - Comparative Example 4);

[0045] Figure 8 : Acoustocurrent diagrams of a single-atom modified two-dimensional piezoelectric nanosheet in Example 1 and Comparative Examples 1-3 of the present invention (Note: Cu-BTO - Example 1; No ultrasonic exfoliation - Comparative Example 3; No acid etching - Comparative Example 2; No sodium deoxycholate modification - Comparative Example 4). Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0048] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0049] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention. Unless otherwise specified, the raw materials used in the following embodiments and comparative examples are all commercially available, and the same raw materials were used in parallel experiments.

[0050] Example 1

[0051] A method for preparing single-atom modified two-dimensional piezoelectric nanosheets, the structural formula of which is Cu-Bi4Ti3O 12 Cu-BTO, also known as Cu-BTO, is prepared by the following steps:

[0052] (1) Weigh Bi(NO3)3·5H2O and tetrabutyl titanate according to a stoichiometric ratio of 6:5, then add 60 mL of 5 mol / L sodium hydroxide aqueous solution, add sodium oleate, sonicate for 15 min, stir for 1 h, and then carry out hydrothermal reaction at 180℃ for 20 h to obtain hydrothermal product; the molar ratio of sodium oleate, Bi(NO3)3·5H2O, tetrabutyl titanate and sodium hydroxide aqueous solution is 1:6:5:300;

[0053] (2) All hydrothermal products from step (1) were subjected to acid etching in a 3.325 mol / L nitric acid aqueous solution for 12.5 h, and the acid-etched products were obtained by filtration.

[0054] (3) Mix all the acid etching products from step (2) with 50 mg of copper acetylacetonate, calcine them for 1 h under a nitrogen atmosphere and a temperature of 300 °C, and filter to obtain the calcined product.

[0055] (4) 50 mg of the calcined product from step (3) was subjected to ultrasonic exfoliation at a frequency of 400 W for 1.5 h. Then, 50 mg of sodium deoxycholate and 20 mL of water were added for modification. The product was filtered, washed, and freeze-dried to obtain copper atom-modified two-dimensional piezoelectric nanosheets.

[0056] Example 2

[0057] A method for preparing single-atom modified two-dimensional piezoelectric nanosheets, the structural formula of which is Cu-Bi4Ti3O 12 Cu-BTO, also known as Cu-BTO, is prepared by the following steps:

[0058] (1) Weigh Bi(NO3)3·5H2O and tetrabutyl titanate according to a stoichiometric ratio of 6:5, then add 60 mL of 5 mol / L sodium hydroxide aqueous solution, add sodium oleate, sonicate for 15 min, stir for 1 h, and then carry out hydrothermal reaction at 180℃ for 20 h to obtain hydrothermal product; the molar ratio of sodium oleate, Bi(NO3)3·5H2O, tetrabutyl titanate and sodium hydroxide aqueous solution is 1:6:5:300;

[0059] (2) All hydrothermal products from step (1) were subjected to acid etching in a 3.325 mol / L nitric acid aqueous solution for 12.5 h, and the acid-etched products were obtained by filtration.

[0060] (3) Mix all the acid etching products from step (2) with 25 mg of copper acetylacetonate and calcine them at a nitrogen atmosphere and a temperature of 300 °C for 1 h to obtain the calcined product.

[0061] (4) 50 mg of the calcined product from step (3) was subjected to ultrasonic exfoliation at a frequency of 400 W for 1.5 h. Then, 50 mg of sodium deoxycholate and 20 mL of water were added for modification. The product was filtered, washed, and freeze-dried to obtain copper atom-modified two-dimensional piezoelectric nanosheets.

[0062] Example 3

[0063] A method for preparing single-atom modified two-dimensional piezoelectric nanosheets, the structural formula of which is Cu-Bi4Ti3O 12 Cu-BTO, also known as Cu-BTO, is prepared by the following steps:

[0064] (1) Weigh Bi(NO3)3·5H2O and tetrabutyl titanate in a stoichiometric ratio of 6:5, then add 60 mL of 5 mol / L sodium hydroxide aqueous solution, add sodium oleate, sonicate for 15 min, stir for 1 h, and then carry out hydrothermal reaction at 180℃ for 20 h to obtain hydrothermal product; the molar ratio of sodium oleate, Bi(NO3)3·5H2O, tetrabutyl titanate and sodium hydroxide aqueous solution is 1:6:5:300;

[0065] (2) All hydrothermal products from step (1) were subjected to acid etching in a 3.325 mol / L nitric acid aqueous solution for 12.5 h, and the acid-etched products were obtained by filtration.

[0066] (3) Mix all the acid etching products from step (2) with 75 mg of copper acetylacetonate and calcine them at a nitrogen atmosphere and a temperature of 300 °C for 1 h to obtain the calcined product.

[0067] (4) 50 mg of the calcined product from step (3) was subjected to ultrasonic exfoliation at a frequency of 400 W for 1.5 h. Then, 50 mg of sodium deoxycholate and 20 mL of water were added for modification. The product was filtered, washed, and freeze-dried to obtain copper atom-modified two-dimensional piezoelectric nanosheets.

[0068] Example 4

[0069] A method for preparing single-atom modified two-dimensional piezoelectric nanosheets, the structural formula of which is Cu-Bi4Ti3O 12 Cu-BTO, also known as Cu-BTO, is prepared by the following steps:

[0070] (1) Weigh Bi(NO3)3·5H2O and tetrabutyl titanate according to a stoichiometric ratio of 6:5, then add 60 mL of 5 mol / L sodium hydroxide aqueous solution, add sodium oleate, sonicate for 15 min, stir for 1 h, and then carry out hydrothermal reaction at 180℃ for 20 h to obtain hydrothermal product; the molar ratio of sodium oleate, Bi(NO3)3·5H2O, tetrabutyl titanate and sodium hydroxide aqueous solution is 1:6:5:300;

[0071] (2) All hydrothermal products from step (1) were subjected to acid etching in a 3.325 mol / L nitric acid aqueous solution for 12.5 h, and the acid-etched products were obtained by filtration.

[0072] (3) Mix all the acid etching products from step (2) with 100 mg of copper acetylacetonate and calcine them at 300 °C for 1 h under a nitrogen atmosphere to obtain the calcined product.

[0073] (4) 50 mg of the calcined product from step (3) was subjected to ultrasonic exfoliation at a frequency of 400 W for 1.5 h. Then, 50 mg of sodium deoxycholate and 20 mL of water were added for modification. The product was filtered, washed, and freeze-dried to obtain copper atom-modified two-dimensional piezoelectric nanosheets.

[0074] Comparative Example 1

[0075] A method for preparing two-dimensional piezoelectric nanosheets, the structural formula of which is Bi4Ti3O 12 BTO, abbreviated as BTO, is prepared by the following steps:

[0076] (1) Weigh Bi(NO3)3·5H2O and tetrabutyl titanate according to a stoichiometric ratio of 6:5, then add 60 mL of 5 mol / L sodium hydroxide aqueous solution, add sodium oleate, sonicate for 15 min, stir for 1 h, and then carry out hydrothermal reaction at 180℃ for 20 h to obtain hydrothermal product; the molar ratio of sodium oleate, Bi(NO3)3·5H2O, tetrabutyl titanate and sodium hydroxide aqueous solution is 1:6:5:300;

[0077] (2) All hydrothermal products from step (1) were subjected to acid etching in a 3.325 mol / L nitric acid aqueous solution for 12.5 h, and the acid-etched products were obtained by filtration.

[0078] (3) 50 mg of all acid etching products from step (2) were ultrasonically exfoliated at a frequency of 400 W for 1.5 h. Then, 50 mg of sodium deoxycholate and 20 mL were added for modification. The mixture was filtered, washed, and lyophilized to obtain two-dimensional piezoelectric nanosheets.

[0079] Comparative Example 2

[0080] A method for preparing single-atom modified two-dimensional piezoelectric nanosheets, the structural formula of which is Cu-Bi4Ti3O 12 The preparation method includes the following steps:

[0081] (1) Weigh Bi(NO3)3·5H2O and tetrabutyl titanate according to a stoichiometric ratio of 6:5, then add 60 mL of 5 mol / L sodium hydroxide aqueous solution, add sodium oleate, sonicate for 15 min, stir for 1 h, and then carry out hydrothermal reaction at 180℃ for 20 h to obtain hydrothermal product; the molar ratio of sodium oleate, Bi(NO3)3·5H2O, tetrabutyl titanate and sodium hydroxide aqueous solution is 1:6:5:300;

[0082] (2) Mix all the hydrothermal products from step (1) with 50 mg of copper acetylacetonate, calcine them for 1 h under a nitrogen atmosphere and a temperature of 300 °C, and filter to obtain the calcined product.

[0083] (3) 50 mg of the calcined product from step (3) was subjected to ultrasonic exfoliation at a frequency of 400 W for 1.5 h. Then, 50 mg of sodium deoxycholate and 20 mL of water were added for modification. The product was filtered, washed, and freeze-dried to obtain copper atom-modified two-dimensional piezoelectric nanosheets.

[0084] Comparative Example 3

[0085] A method for preparing single-atom modified two-dimensional piezoelectric nanosheets, the structural formula of which is Cu-Bi4Ti3O 12 Cu-BTO, also known as Cu-BTO, is prepared by the following steps:

[0086] (1) Weigh Bi(NO3)3·5H2O and tetrabutyl titanate according to a stoichiometric ratio of 6:5, then add 60 mL of 5 mol / L sodium hydroxide aqueous solution, add sodium oleate, sonicate for 15 min, stir for 1 h, and then carry out hydrothermal reaction at 180℃ for 20 h to obtain hydrothermal product; the molar ratio of sodium oleate, Bi(NO3)3·5H2O, tetrabutyl titanate and sodium hydroxide aqueous solution is 1:6:5:300;

[0087] (2) All hydrothermal products from step (1) were subjected to acid etching in a 3.325 mol / L nitric acid aqueous solution for 12.5 h, and the acid-etched products were obtained by filtration.

[0088] (3) Mix all the acid etching products from step (2) with 50 mg of copper acetylacetonate, calcine them for 1 h under a nitrogen atmosphere and a temperature of 300 °C, and filter to obtain the calcined product.

[0089] (4) 50 mg of the calcined product from step (3) was subjected to ultrasonic exfoliation at a frequency of 400 W for 1.5 h. The product was then washed and freeze-dried to obtain copper atom-modified two-dimensional piezoelectric nanosheets.

[0090] Comparative Example 4

[0091] A method for preparing single-atom modified two-dimensional piezoelectric nanosheets, the structural formula of which is Cu-Bi4Ti3O 12 Cu-BTO, also known as Cu-BTO, is prepared by the following steps:

[0092] (1) Weigh Bi(NO3)3·5H2O and tetrabutyl titanate according to a stoichiometric ratio of 6:5, then add 60 mL of 5 mol / L sodium hydroxide aqueous solution, add sodium oleate, sonicate for 15 min, stir for 1 h, and then carry out hydrothermal reaction at 180℃ for 20 h to obtain hydrothermal product; the molar ratio of sodium oleate, Bi(NO3)3·5H2O, tetrabutyl titanate and sodium hydroxide aqueous solution is 1:6:5:300;

[0093] (2) All hydrothermal products from step (1) were subjected to acid etching in a 3.325 mol / L nitric acid aqueous solution for 12.5 h, and the acid-etched products were obtained by filtration.

[0094] (3) Mix all the acid etching products from step (2) with 50 mg of copper acetylacetonate, calcine them for 1 h under a nitrogen atmosphere and a temperature of 300 °C, and filter to obtain the calcined product.

[0095] (4) Add 50mg of the calcined product from step (3) to 50mg of sodium deoxycholate and 20mL of water for modification, filter, wash and freeze dry to obtain copper atom modified two-dimensional piezoelectric nanosheets.

[0096] Performance testing

[0097] 1. The copper atom-modified two-dimensional piezoelectric nanosheets prepared in Example 1 were tested using an X-ray diffractometer. The XRD pattern obtained is as follows. Figure 1 As shown, the piezoelectric nanosheets prepared in Example 1 are pure phase.

[0098] 2. The hydrated particle size of the hydrothermal product from step (1), the acid etching product from step (2), and the copper atom-modified two-dimensional piezoelectric nanosheets prepared in step (4) of Example 1 was measured using dynamic light scattering technology. The hydrated particle size diagrams of the hydrothermal product from step (1) and the acid etching product from step (2) of Example 1 are shown below. Figure 2 As shown, the hydrated particle size distribution of the copper atom-modified two-dimensional piezoelectric nanosheets prepared in step (4) of Example 1 is as follows. Figure 3 As shown. Simultaneously, the hydration particle size of the final products prepared in Example 1 and Comparative Examples 2-4 was measured using dynamic light scattering technology. The resulting hydration particle size diagrams are shown below. Figure 7 As shown.

[0099] like Figure 2 As shown, the particle size of the acid-etched products is smaller than that of the hydrothermal products, indicating that the acid etching process reduces the material size. Figure 2-3 As shown, the particle size of the copper atom-modified two-dimensional piezoelectric nanosheets is smaller than that of the acid etching product, indicating that the ultrasonic exfoliation in step (4) further reduces the material size, thus obtaining two-dimensional piezoelectric nanosheets with hydrated particle sizes at the nanometer level. Figure 7 As shown, Example 1 improved the dispersibility of nanomaterials by adding sodium deoxycholate, while Comparative Example 4 did not add sodium deoxycholate for surface modification, resulting in the final nanomaterial having too small a particle size, which affected the dispersibility of the nanomaterials.

[0100] 3. The copper atom-modified two-dimensional piezoelectric nanosheets prepared in Examples 1-4 and Comparative Examples 2-4 were subjected to acoustic current testing, i.e., the current response under ultrasonic stimulation was measured using an electrochemical workstation. The specific steps are as follows:

[0101] 3 mg of the solid materials from Examples 1-4 and Comparative Examples 2-4 were dissolved in 500 μL of solvent, respectively. The mixed solvent consisted of ethanol and naphthol in a volume ratio of 48:2. 50 μL of the mixed solution was taken and coated onto the conductive surface of conductive glass for 1 cm. -2 After the solvent evaporates, it serves as the working electrode. A reference electrode (saturated calomel electrode) and an auxiliary electrode (platinum sheet) are also set up. All three electrodes are inserted into a 0.5 mol / L Na₂SO₄ electrolyte solution. Continuous ultrasonic irradiation is used as the excitation source for the current signal. One test cycle consists of a 30-second US process and a 60-second resting process. Multiple cycles of acoustic-current signals are detected. Ultrasonic parameters: 2 W / cm². -2 1.0MHz, 50% duty cycle, 3min. Test results are as follows. Figure 4 and Figure 8As shown, compared to Examples 2-4, the piezoelectric nanosheets in Example 1 exhibit the largest acoustic-current response when the copper loading is 50 mg. Furthermore, compared to Comparative Examples 2-4, Example 1 shows the largest acoustic-current response when subjected to acid etching, ultrasonic exfoliation, and sodium deoxycholate modification, demonstrating that the charge separation efficiency of the material in Example 1 is higher than that of Examples 2-4 and Comparative Examples 2-4.

[0102] 4. Test the catalytic performance of the two-dimensional piezoelectric nanomaterials of Example 1 and Comparative Example 1 that resemble glutathione peroxidase, including the following steps:

[0103] (1) The two-dimensional piezoelectric nanosheets prepared in Example 1 and Comparative Example 1 were dissolved in PBS solution with pH 6.5 to obtain a material solution with a concentration of 25 μg / mL. A glutathione (GSH) solution with a concentration of 4 mmol / L was prepared with PBS solution with pH 6.5, and a DTNB solution with a concentration of 6.5 mmol / L was prepared with DMSO.

[0104] (2) Take 3 mL of material solution, add 150 μL of GSH solution, react for different times (0 min, 15 min, 30 min, 45 min, 60 min, 90 min), add 75 μL of DTNB solution, react for 15 min and then measure the UV absorption value at 412 nm.

[0105] Since glutathione peroxidase can consume GSH, Cu-Bi4Ti3O from Example 1 was used. 12 And Bi4Ti3O in Comparative Example 4 12 GSH is consumed, and the remaining GSH is reacted with DTNB to produce yellow oxidized glutathione (GSSG) and trinitrobenzene (TNB). The deeper the yellow color of the resulting solution, the less GSH is consumed, indicating lower catalytic activity. The absorbance at 412 nm is measured using a UV-Vis spectrometer to reflect the activity of the material-like glutathione peroxidase. The test results are as follows: Figure 5-6 As shown.

[0106] like Figure 5 As shown, Cu-Bi4Ti3O in Example 1 12 The absorbance of the sample at 412 nm gradually decreased over time, indicating that Cu-Bi4Ti3O 12 It can effectively consume GSH, while Figure 6 Bi4Ti3O in Comparative Example 1 12 The fact that almost no GSH is consumed within 90 minutes indicates that Cu-Bi4Ti3O 12 The catalytic activity is significantly higher than that of Bi4Ti3O 12 This is because the presence of copper single atoms enhances the catalytic activity of piezoelectric nanomaterials.

[0107] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for preparing single-atom modified two-dimensional piezoelectric nanosheets, characterized in that, Includes the following steps: (1) Acid etching treatment was performed on the bismuth-based piezoelectric material to obtain the acid etching product; (2) The acid etching product is mixed with a salt containing metal atoms and calcined in an inert atmosphere to obtain a calcined product; (3) The calcined product is subjected to ultrasonic exfoliation and polymer modification to obtain single-atom modified two-dimensional piezoelectric nanosheets.

2. The method for preparing a single-atom modified two-dimensional piezoelectric nanosheet as described in claim 1, characterized in that, In step (2), the metal atoms in the salt containing metal atoms are at least one of aluminum, cobalt, nickel, copper, zinc, iron, chromium, titanium, manganese, potassium, and zirconium; And / or, in step (2), the salt containing metal atoms is an acetylacetonate; And / or, in step (2), the molar ratio of the acid etching product to the salt containing metal atoms is (1.7-3.4):(0.09-0.4).

3. The method for preparing a single-atom modified two-dimensional piezoelectric nanosheet as described in claim 1, characterized in that, In step (1), the preparation method of the bismuth-based piezoelectric material includes the following steps: adding Bi source, Ti source and sodium oleate to an alkaline solution, mixing them evenly and then carrying out a hydrothermal reaction to obtain the bismuth-based piezoelectric material.

4. The method for preparing a single-atom modified two-dimensional piezoelectric nanosheet as described in claim 3, characterized in that, The bismuth-based piezoelectric material is Bi4Ti3O 12 The bismuth-based piezoelectric material is micron-sized; And / or, in the method for preparing the bismuth-based piezoelectric material, the Bi source is Bi(NO3)3·5H2O; And / or, in the method for preparing the bismuth-based piezoelectric material, the Ti source is tetrabutyl titanate.

5. The method for preparing a single-atom modified two-dimensional piezoelectric nanosheet as described in claim 3, characterized in that, In the preparation method of the bismuth-based piezoelectric material, the molar ratio of the Bi source to the Ti source is (4-8):(3-7); And / or, in the method for preparing the bismuth-based piezoelectric material, the molar ratio of sodium oleate, Bi source and Ti source is (1-2):(4-8):(3-7); And / or, in the preparation method of the bismuth-based piezoelectric material, the molar ratio of the alkaline solution, sodium oleate, Bi source and Ti source is (200-400):(1-2):(4-8):(3-7). And / or, in the method for preparing the bismuth-based piezoelectric material, the concentration of alkali in the alkaline solution is 3-8 mol / L; And / or, in the method for preparing the bismuth-based piezoelectric material, the alkali in the alkaline solution is sodium hydroxide; And / or, in the preparation method of the bismuth-based piezoelectric material, the hydrothermal reaction temperature is 160-220℃ and the time is 15-30h.

6. The method for preparing a single-atom modified two-dimensional piezoelectric nanosheet as described in claim 1, characterized in that, In step (1), the acid used for acid etching is nitric acid; And / or, in step (1), the acid concentration for the acid etching treatment is 2-5 mol / L; And / or, in step (1), the acid etching process takes 10-15 hours.

7. The method for preparing a single-atom modified two-dimensional piezoelectric nanosheet as described in claim 1, characterized in that, In step (2), the inert atmosphere is at least one of nitrogen, helium, neon, and argon; And / or, in step (2), the calcination temperature is 280-320℃ and the calcination time is 1-5h.

8. The method for preparing a single-atom modified two-dimensional piezoelectric nanosheet as described in claim 1, characterized in that, In step (3), the frequency of ultrasonic ablation is 300-500W, and the time is 1-3h; And / or, in step (3), the polymer modification is to add sodium deoxycholate and water to the calcined product, wherein the mass ratio of the calcined product to sodium deoxycholate is 1:(0.5-2):(0.3-0.5).

9. A single-atom modified two-dimensional piezoelectric nanosheet prepared by the method described in any one of claims 1-8.

10. The application of a single-atom modified two-dimensional piezoelectric nanosheet as described in claim 9 in the preparation of products for catalytic degradation, disinfection and antibacterial purposes, or drug delivery.

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