A modified barium titanate nanoparticle with strong piezoelectric effect, its preparation method and application

Abstract

This application relates to the field of piezoelectric materials technology, and discloses a modified barium titanate nanoparticle with a strong piezoelectric effect, its preparation method, and its applications. The modified barium titanate nanoparticle with a strong piezoelectric effect is formed by etching barium titanate into its crystal lattice to form Ba. 2+ Vacancies are then filled with Ba using a hydrothermal method to introduce doped metal ions. 2+ The barium titanate is prepared by creating vacancies; the doped metal is a metal that forms thermally stable ions or complex ions under alkaline conditions. This application involves etching and secondary hydrothermal treatment of barium titanate to induce A-site ion exchange in its surface lattice, constructing radial chemical composition and strain gradients, thus forming a flexural effect. This application couples the flexural effect with the piezoelectric effect to enhance the piezoelectric properties of barium titanate. After this treatment, the piezoelectric coefficient of barium titanate is significantly enhanced from 29.2 pm / V to 129.9 pm / V, an increase of 345%, achieving a significant enhancement in piezoelectric performance. It exhibits excellent performance in applications such as pollutant degradation and tumor treatment.

Description

Technical Field

[0001] This application relates to the field of piezoelectric materials technology, specifically to a modified nano-barium titanate with a strong piezoelectric effect, its preparation method, and its application. Background Technology

[0002] The piezoelectric effect is a mechanical-electromagnetic coupling phenomenon in which the internal structure of a non-centrosymmetric crystal shifts under mechanical force, causing the centers of positive and negative charges to separate and generate an internal electric field, ultimately resulting in the accumulation of positive and negative charges on opposite surfaces.

[0003] Materials exhibiting piezoelectric effect are called piezoelectric materials, and they are currently widely used in various fields such as wastewater treatment, water splitting, organic synthesis, and CO2 reduction. Among many piezoelectric materials, BaTiO3 stands out due to its high piezoelectric coefficient (d). 33 BaTiO3 has attracted much attention due to its good biocompatibility. It belongs to the typical perovskite structure (ABO3), O 2- Forming a regular octahedron, Ti 4+ Located at the center of the octahedron, Ba 2+ It is located in the interstices of the octahedron, and its piezoelectricity originates from the Ti in the Ti-O6 octahedron. 4+ The eccentric displacement induces electronic / ionic polarization, accompanied by a decrease in cell symmetry from cubic to tetragonal.

[0004] Piezoelectric materials can also be used as acoustic sensors. Thanks to their unique piezoelectric effect, under the influence of external ultrasound, piezoelectric acoustic sensors can establish an internal electric field, causing band structure bending and suppressing carrier recombination, thus greatly enhancing the generation efficiency of ROS. In recent years, numerous studies have reported on different strategies to improve BaTiO3-based materials to develop piezoelectric acoustic sensors with superior performance, such as ion doping, oxygen vacancies engineering, phase engineering, and heterojunction engineering, to improve BaTiO3 carrier lifetime or substrate selectivity.

[0005] However, there are few reports on improving the piezoelectric properties of BaTiO3, and its piezoelectric performance still needs to be enhanced. Modulating the mechanical-electromagnetic coupling of BaTiO3 to improve its piezoelectric properties is a feasible approach. The coupling effect between flexoelectricity and piezoelectricity is one of the recently debated methods for manipulating the piezoelectric response, proposing a direct strategy to enhance mechanical-electromagnetic coupling performance. However, controlling the coupling between flexoelectricity and piezoelectricity is very challenging because the internal strain gradient of nanoparticles is difficult to control and observe. Summary of the Invention

[0006] This application provides a modified barium titanate nanoparticle with strong piezoelectric effect, its preparation method and application, aiming to solve the problem of low piezoelectric performance of existing piezoelectric materials.

[0007] To achieve the above objectives, the present application adopts the following technical solution.

[0008] A first aspect of this application provides a modified barium titanate nanoparticle with a strong piezoelectric effect, which is formed by etching barium titanate into its lattice to form Ba. 2+ Vacancies are then filled with Ba using a hydrothermal method to introduce doped metal ions. 2+ Prepared using vacancy;

[0009] The doped metal is a metal that forms thermally stable ions or complex ions under alkaline conditions.

[0010] Preferably, the doped metal is at least one of copper, silver, gold, or palladium.

[0011] A second aspect of this application provides a method for preparing the aforementioned modified barium titanate nanoparticles with a strong piezoelectric effect, comprising:

[0012] S1, Barium titanate is dispersed in an acidic solution and stirred to react; the solid phase is collected, washed, and dried to obtain a product containing Ba... 2+ Vacant barium titanate;

[0013] S2, the one with Ba 2+ Barium titanate with vacancy is dispersed in a solution of doped metal salt, ammonia is added, and the mixture is stirred evenly to obtain a dispersion.

[0014] The dispersion was transferred to a high-pressure reactor for hydrothermal reaction. The solid phase was collected, washed, and dried to obtain modified barium titanate nanoparticles with strong piezoelectric effect.

[0015] Preferably, the acid solution is hydrochloric acid with a pH of 3 to 5; and the concentration of barium titanate in the acid solution is 0.005 to 0.5 mol / L.

[0016] Preferably, the doped metal salt is a water-soluble salt of copper, silver, gold, or palladium.

[0017] More preferably, the doped metal salt is copper chloride or copper nitrate.

[0018] More preferably, the concentration of the doped metal salt solution is 0.001–0.1 mol / L;

[0019] The dispersion contains Ba 2+ The concentration of vacant barium titanate is 0.01–1 mol / L; the concentration of the ammonia solution is 1–10 mol / L.

[0020] Preferably, the hydrothermal reaction temperature is 120–220°C, and the reaction time is 6–24 hours.

[0021] A third aspect of this application provides the application of the aforementioned modified nano-barium titanate with strong piezoelectric effect in the piezoelectric catalytic degradation of organic matter.

[0022] A fourth aspect of this application provides the application of the aforementioned modified nano-barium titanate with strong piezoelectric effect in tumor therapeutic drugs.

[0023] Compared with the prior art, the beneficial effects of this application are as follows:

[0024] This application significantly enhances the piezoelectric properties of barium titanate by modifying its surface lattice, while preserving its inherent semiconductor properties to the maximum extent. Specifically, this application involves etching and performing secondary hydrothermal treatment on barium titanate to induce A-site ion exchange in its surface lattice, constructing radial chemical composition and strain gradients. The strain gradient breaks its local inversion symmetry, generating polarization with a specific direction and achieving a piezoelectric-like response, namely the flexoelectric effect. This application couples the flexoelectric effect with the piezoelectric effect to enhance the piezoelectric properties of barium titanate. After this treatment, the piezoelectric coefficient of barium titanate is significantly increased from 29.2 pm / V to 129.9 pm / V, an improvement of 345%.

[0025] The modified barium titanate nanoparticles prepared in this application exhibit a significantly enhanced piezoelectric effect, far exceeding the improvement of existing technologies. They demonstrate excellent performance in areas such as pollutant degradation and tumor therapy. When used for piezoelectric catalysis of organic matter degradation, after 10 minutes of ultrasonic irradiation, their degradation efficiency for methylene blue (MB) is 1.93 times that of barium titanate. When used as a tumor therapy drug in tumor-bearing mice, they achieve a tumor inhibition rate of 83.7%, while barium titanate's tumor inhibition rate is only 24.5%. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 SEM, TEM and EDS spectra of BTO prepared for this application;

[0028] Figure 2 SEM, TEM and EDS spectra of Cu-BTO prepared in this application;

[0029] Figure 3 SEM and EDS spectra of Cu-BTO prepared as a comparative example;

[0030] Figure 4 The graph shows the piezoelectric coefficient test results of Cu-BTO prepared in the embodiments and comparative examples of this application;

[0031] Figure 5 The image shows the piezoelectric catalytic degradation results of methylene blue by Cu-BTO prepared in this application.

[0032] Figure 6 The image shows the therapeutic effect of Cu-BTO prepared in this application on tumors. Detailed Implementation

[0033] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0034] In the following description of this embodiment, the terms "including", "comprising", "having", and "containing" are all open-ended terms, meaning that they include but are not limited to.

[0035] In the following description of this embodiment, the term "and / or" is used to describe the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, B existing alone, and A and B existing simultaneously. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0036] In the following description of this embodiment, the term "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0037] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0038] Those skilled in the art should understand that, in the following description of the embodiments of this application, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0039] Those skilled in the art will understand that the numerical ranges in the embodiments of this application should be understood as each intermediate value between the upper and lower limits of the specifically disclosed range. Each smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this application. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0040] Unless otherwise stated, the technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. While this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this application. 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.

[0041] In a first aspect, this application provides a modified barium titanate nanoparticle with a strong piezoelectric effect, which forms Ba in its lattice by etching barium titanate. 2+ Vacancies are then filled with Ba using a hydrothermal method to introduce doped metal ions. 2+ Prepared using vacancy;

[0042] The doped metal is a metal that forms thermally stable ions or complex ions under alkaline conditions; in this application, the doped metal may be at least one of copper, silver, gold or palladium.

[0043] This application significantly enhances the piezoelectric properties of barium titanate by modifying its surface lattice, while preserving its semiconductor properties to the maximum extent. Specifically, this application involves etching and performing secondary hydrothermal treatment on barium titanate to induce A-site ion exchange in its surface lattice, constructing radial chemical composition and strain gradients. The strain gradient breaks its local inversion symmetry, generating polarization with a specific direction and achieving a piezoelectric-like response, i.e., the flexoelectric effect. This application couples the flexoelectric effect with the piezoelectric effect to enhance the piezoelectric properties of barium titanate.

[0044] After this treatment, the piezoelectric coefficient of barium titanate was significantly enhanced from 29.2 pm / V to 129.9 pm / V, an increase of 345%.

[0045] Secondly, this application provides a method for preparing the aforementioned modified barium titanate nanoparticles with a strong piezoelectric effect, comprising:

[0046] S1, Barium titanate (BTO) is dispersed in an acid solution and stirred to react; the solid phase is collected, washed, and dried to obtain a product containing Ba... 2+ Barium titanate with a vacancy is denoted as B. 1-x TO;

[0047] In this application, the acid solution can be hydrochloric acid or nitric acid with a pH of 3 to 5, preferably hydrochloric acid with a pH of 3 to 5; the concentration of barium titanate in the acid solution is 0.005 to 0.5 mol / L, preferably 0.05 to 0.06 mol / L.

[0048] S2, the one with Ba 2+ Barium titanate with vacancy is dispersed in a solution of doped metal salt, ammonia is added, and the mixture is stirred evenly to obtain a dispersion.

[0049] The dispersion was transferred to a high-pressure reactor for hydrothermal reaction. The solid phase was collected, washed, and dried to obtain modified barium titanate nanoparticles with a strong piezoelectric effect, denoted as Cu-BTO. The hydrothermal reaction temperature was 120–220 °C, and the reaction time was 6–24 h, preferably 18 h.

[0050] In this application, the doped metal salt is a water-soluble salt of copper, silver, gold, or palladium, preferably a water-soluble salt of copper, such as copper chloride or copper nitrate and their hydrates. Preferably, the concentration of the doped metal salt solution is 0.001–0.1 mol / L, more preferably 0.008–0.024 mol / L.

[0051] In this application, ammonia is used to stabilize the doped metal ions, thereby preventing the formation of oxides of the doped metals and impairing the piezoelectric properties of the final barium titanate.

[0052] Specifically, this application stabilizes copper ions by adding ammonia, preventing the formation of copper oxide impurities, thereby significantly improving the piezoelectric properties of the final modified nano-barium titanate. Without ammonia or other alkaline substances, B 1-x TO does not react with copper salts, making it impossible to fill Ba with copper ions. 2+ An empty slot will ultimately result in B. 1-x TO. However, if other alkaline solutions are used instead of ammonia, such as sodium hydroxide solution, copper ions cannot exist stably under the alkaline conditions of high temperature and high pressure. Under an electron microscope, a large number of plate-like copper oxide impurities can be observed, which fails to achieve the purpose of enhancing piezoelectric properties.

[0053] In this application, the dispersion contains Ba 2+ The concentration of vacant barium titanate is 0.01–1 mol / L, preferably 0.3–0.4 mol / L; the concentration of ammonia water is 1–10 mol / L, preferably 3–5 mol / L. Under these conditions, the piezoelectric properties are enhanced most effectively.

[0054] The modified barium titanate nanoparticles prepared in this application exhibit a significant enhancement in piezoelectric properties, far exceeding the improvement of existing technologies. They demonstrate excellent performance in applications such as pollutant degradation and tumor treatment.

[0055] The modified barium titanate nanoparticles prepared in this application, which have a strong piezoelectric effect, can improve the generation efficiency of reactive oxygen species and can be used for piezoelectric catalysis of organic matter degradation. After a 10-minute ultrasonic irradiation process, its degradation efficiency of methylene blue (MB) is 1.93 times that of barium titanate.

[0056] The modified barium titanate nanoparticles with strong piezoelectric effect prepared in this application contain multiple reactive sites, which can broaden substrate selectivity, effectively regulate the tumor suppressor microenvironment, and improve the efficacy of tumor therapy. It can be used in tumor therapeutic drugs or in the preparation of tumor therapeutic drugs. When used in tumor therapeutic drugs in tumor-bearing mice, it achieved a tumor inhibition rate of 83.7%, while barium titanate only achieved a tumor inhibition rate of 24.5%.

[0057] The present application will be further illustrated by the following examples.

[0058] Example 1

[0059] This embodiment provides a method for preparing modified barium titanate nanoparticles with a strong piezoelectric effect, comprising:

[0060] Step 1. Preparation of tetragonal barium titanate by hydrothermal method:

[0061] 17.02 g of tetrabutyl titanate was dissolved in 20 mL of ethanol, stirred at 500 rpm, and 7 mL of ammonia was added dropwise to form a homogeneous white emulsion. 14.2 g of barium hydroxide was dissolved in water and added to the white emulsion at 80 °C. After stirring at 500 rpm for 30 min, the solution was transferred to a 100 mL high-pressure reactor with a polytetrafluoroethylene liner. The reactor was placed at 200 °C and reacted for 48 h. The resulting white particles were washed three times with 5% acetic acid solution and ethanol, and dried overnight at 80 °C to obtain tetragonal titanate, denoted as BTO.

[0062] Step 2. Acid etching of barium titanate to produce Ba 2+ Empty space:

[0063] BTO was uniformly dispersed in hydrochloric acid at pH 3 to prepare a BTO concentration of 0.05 mol / L. The solution was stirred at 500 rpm for 12 h, and the solid phase was collected. The white particles obtained after etching were washed three times alternately with water and ethanol, and then dried overnight at 80 °C to obtain a solution with Ba... 2+ Barium titanate with a vacancy is denoted as B. 1-x TO.

[0064] Step 3. Using Cu 2+ Fill Ba 2+ Empty space:

[0065] Prepare a 0.008 mol / L copper salt aqueous solution using copper nitrate trihydrate, and add B... 1-x TO is dispersed in an aqueous solution of copper salt, wherein B 1-x The TO concentration was 0.3 mol / L. Ammonia was then added to the copper salt aqueous solution to bring the ammonia concentration to 3 mol / L, forming a purple dispersion. After stirring the dispersion for 30 min, it was transferred to a 50 mL high-pressure reactor with a polytetrafluoroethylene liner. The reactor was placed at 200 °C for 18 h. The solid phase was separated and collected. The resulting pale blue particles were washed three times with ethanol and dried overnight at 80 °C to obtain modified barium titanate nanoparticles with a strong piezoelectric effect.

[0066] Example 2

[0067] This embodiment provides a method for preparing modified barium titanate nanoparticles with a strong piezoelectric effect, comprising:

[0068] Step 1. Preparation of tetragonal barium titanate by hydrothermal method:

[0069] 17.02 g of tetrabutyl titanate was dissolved in 20 mL of ethanol, stirred at 500 rpm, and 7 mL of ammonia was added dropwise to form a homogeneous white emulsion. 14.2 g of barium hydroxide was dissolved in water and added to the white emulsion at 80 °C. After stirring at 500 rpm for 30 min, the solution was transferred to a 100 mL high-pressure reactor with a polytetrafluoroethylene liner. The reactor was placed at 200 °C and reacted for 48 h. The resulting white particles were washed three times with 5% acetic acid solution and ethanol, and dried overnight at 80 °C to obtain tetragonal titanate, denoted as BTO.

[0070] Step 2. Acid etching of barium titanate to produce Ba 2+ Empty space:

[0071] BTO was uniformly dispersed in hydrochloric acid at pH 3 to prepare a BTO concentration of 0.05 mol / L. The solution was stirred at 500 rpm for 12 h, and the solid phase was collected. The white particles obtained after etching were washed three times alternately with water and ethanol, and then dried overnight at 80 °C to obtain a solution with Ba... 2+ Barium titanate with a vacancy is denoted as B. 1-x TO.

[0072] Step 3. Using Cu 2+ Fill Ba 2+ Empty space:

[0073] Prepare a 0.0016 mol / L copper salt aqueous solution using copper nitrate trihydrate, and add B... 1-x TO is dispersed in an aqueous solution of copper salt, wherein B 1-x The TO concentration was 0.34 mol / L. Ammonia was then added to the copper salt aqueous solution to bring the ammonia concentration to 3 mol / L, forming a purple dispersion. After stirring the dispersion for 30 min, it was transferred to a 50 mL high-pressure reactor with a polytetrafluoroethylene liner. The reactor was placed at 200 °C for 18 h. The solid phase was separated and collected. The resulting pale blue particles were washed three times with ethanol and dried overnight at 80 °C to obtain modified barium titanate nanoparticles with a strong piezoelectric effect.

[0074] Example 3

[0075] This embodiment provides a method for preparing modified barium titanate nanoparticles with a strong piezoelectric effect, comprising:

[0076] Step 1. Preparation of tetragonal barium titanate by hydrothermal method:

[0077] 17.02 g of tetrabutyl titanate was dissolved in 20 mL of ethanol, stirred at 500 rpm, and 7 mL of ammonia was added dropwise to form a homogeneous white emulsion. 14.2 g of barium hydroxide was dissolved in water and added to the white emulsion at 80 °C. After stirring at 500 rpm for 30 min, the solution was transferred to a 100 mL high-pressure reactor with a polytetrafluoroethylene liner. The reactor was placed at 200 °C and reacted for 48 h. The resulting white particles were washed three times with 5% acetic acid solution and ethanol, and dried overnight at 80 °C to obtain tetragonal titanate, denoted as BTO.

[0078] Step 2. Acid etching of barium titanate to produce Ba 2+ Empty space:

[0079] BTO was uniformly dispersed in hydrochloric acid at pH 3 to prepare a BTO concentration of 0.06 mol / L. The solution was stirred at 500 rpm for 12 h, and the solid phase was collected. The white particles obtained after etching were washed three times alternately with water and ethanol, and then dried overnight at 80 °C to obtain a solution with Ba... 2+ Barium titanate with a vacancy is denoted as B. 1-x TO.

[0080] Step 3. Using Cu 2+ Fill Ba 2+ Empty space:

[0081] Prepare a 0.0024 mol / L copper salt aqueous solution using copper nitrate trihydrate, and add B... 1-x TO is dispersed in an aqueous solution of copper salt, wherein B 1-x The TO concentration was 0.4 mol / L. Ammonia was then added to the copper salt aqueous solution to bring the ammonia concentration to 5 mol / L, forming a purple dispersion. After stirring the dispersion for 30 min, it was transferred to a 50 mL high-pressure reactor with a polytetrafluoroethylene liner. The reactor was placed at 200 °C for 18 h. The solid phase was separated and collected. The resulting pale blue particles were washed three times with ethanol and dried overnight at 80 °C to obtain modified barium titanate nanoparticles with a strong piezoelectric effect.

[0082] Example 4

[0083] The difference between Example 4 and Example 1 is that in step 3, the reactor is placed at 200°C for 12 hours, while the rest is the same as in Example 1.

[0084] Example 5

[0085] The difference between Example 5 and Example 1 is that in step 3, the reactor is placed at 200°C for 24 hours, while the rest is the same as in Example 1.

[0086] Comparative Example

[0087] The difference between the comparative example and Example 1 is that in step 3, sodium hydroxide solution is used instead of ammonia water, while the rest are the same as in Example 1.

[0088] The BTO, Cu-BTO prepared in Example 1 and the modified barium titanate nanoparticles prepared in the comparative example were subjected to SEM, TEM and EDS tests. The morphology of the nanoparticles was directly observed by SEM and TEM, and the elemental composition of the nanoparticles was determined by TEM and EDS.

[0089] Test results are as follows Figure 1 , Figure 2 and Figure 3 As shown. Among them, Figure 1 From left to right: SEM, TEM, and EDS spectra of BTO. Figure 2 From left to right: SEM, TEM, and EDS spectra of Cu-BTO. Figure 3 From left to right, the images show the SEM and EDS spectra of the comparatively prepared barium titanate nanoparticles.

[0090] from Figures 1-3 It can be seen that the morphology of BTO and Cu-BTO did not change significantly. Since ammonia stabilized the copper ions, no copper oxide impurities were formed. EDS elemental distribution shows that Cu is enriched on Cu-BTO, confirming Cu... 2+ Successfully entered the Ba produced by etching 2+ Vacancies. Conversely, in the comparative example, when sodium hydroxide was used instead of ammonia, a large number of plate-like copper oxide impurities appeared in the nano-barium titanate, which not only failed to enhance the piezoelectric properties but may also damage them.

[0091] The piezoelectric coefficients d of BTO and Cu-BTO prepared in Example 1, as well as Cu-BTO prepared in Examples 4 and 5, were measured using piezoelectric force microscopy (PFM). 33 The numerical value, the result is as follows Figure 4 As shown. From Figure 4 It can be seen that the piezoelectric coefficient of Cu-BTO is higher than that of BTO, and the degree of increase is related to the hydrothermal reaction time. After a hydrothermal reaction time of 12 hours, the piezoelectric coefficient d of Cu-BTO... 33 It rises to 31.98 pm / V; and after 18 hours of hydrothermal reaction, the piezoelectric coefficient d of Cu-BTO... 33 The value increased to 129.91 pm / V, a 345% improvement over BTO's 29.22 pm / V, demonstrating a very significant enhancement effect. With the extension of the hydrothermal reaction time, when the reaction time reached 24 hours, the Cu-BTO piezoelectric coefficient d... 33 The enhancement effect decreased to 92.98 pm / V. The mechanism is that as the hydrothermal reaction proceeds, Cu... 2+Gradually entering the Ba produced by etching 2+ Vacancies. After the hydrothermal reaction reaches 12 hours, Cu 2+ Ba enters the etched Ba 2+ The number of vacancies begins to increase, and after 18 hours of reaction, Cu 2+ Fill Ba 2+ The number of vacancies reaches its maximum; as time progresses, Cu... 2+ Fill Ba 2+ The number of vacant positions has decreased.

[0092] The piezoelectric catalytic degradation effects of BTO and Cu-BTO prepared in Example 1 on methylene blue (MB) were tested. The specific test method was as follows: BTO and Cu-BTO were dispersed at a concentration of 1 mg / mL in a 10 mg / L MB solution, and the reaction was initiated by ultrasonic irradiation of the dispersion system. Every 2 minutes, 1 mL of each reaction system was taken, centrifuged, and the supernatant was measured to detect the absorbance at 664 nm. The test results are shown below. Figure 5 As shown.

[0093] from Figure 5 It can be seen that both BTO and Cu-BTO can induce MB degradation under ultrasound, and the degree of degradation increases with the extension of ultrasound irradiation time. When irradiated for the same time, the degradation intensity of Cu-BTO as a piezoelectric catalyst is significantly stronger than that of BTO, indicating that Cu-BTO benefits from its enhanced piezoelectric properties and has a stronger piezoelectric catalytic effect under ultrasound.

[0094] The therapeutic effects of BTO and Cu-BTO prepared in Example 1 on tumors were tested. The specific testing method was as follows:

[0095] First, a subcutaneous 4T1 tumor model was constructed in the right groin of 6-week-old female BALB / c mice. The tumor volume reached 150 mm². 3 Treatment then began. On days 0, 2, and 4 of treatment, PBS, BTO, and Cu-BTO were injected via tail vein, respectively. Four hours after injection, the tumor site was irradiated with ultrasound. Tumor growth in each treatment group was recorded every other day. Test results are as follows: Figure 6 As shown in the figure. Among them, the PBS+US group received PBS via tail vein injection and ultrasound therapy; the BTO+US group received BTO via tail vein injection and ultrasound therapy; and the Cu-BTO+US group received Cu-BTO via tail vein injection and ultrasound therapy.

[0096] from Figure 6It was found that the tumor treatment effect of the BTO+US group was only slightly better than that of the PBS+US group, while the treatment effect of the Cu-BTO+US group was significantly better than that of both the PBS+US and BTO+US groups. The tumor inhibition rate of the Cu-BTO+US group reached 83.7%, while that of the BTO+US group was only 24.5%. The test results indicate that the Cu-BTO prepared in this application can broaden substrate selectivity, effectively regulate the tumor inhibitory microenvironment, and improve the efficacy of tumor treatment.

[0097] Although this application has been described in detail in this specification with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, such modifications or improvements made without departing from the spirit of this application are all within the scope of protection claimed in this application.

Claims

1. A method for preparing modified barium titanate nanoparticles with strong piezoelectric effect, characterized in that, include: S1, Barium titanate is dispersed in an acid solution and stirred to react; Collect the solid phase, wash and dry it to obtain Ba. 2+ Vacant barium titanate; S2, the one with Ba 2+ Barium titanate with vacancy is dispersed in a solution of a doped metal salt, ammonia is added, and the mixture is stirred until homogeneous to obtain a dispersion; the doped metal salt is a water-soluble salt of copper. The dispersion was transferred to a high-pressure reactor for hydrothermal reaction. The solid phase was collected, washed, and dried to obtain modified barium titanate nanoparticles with strong piezoelectric effect.

2. The preparation method according to claim 1, characterized in that, The acid solution is hydrochloric acid with a pH of 3-5; The concentration of barium titanate in the acid solution is 0.005~0.5 mol / L.

3. The preparation method according to claim 1, characterized in that, The doped metal salt is copper chloride or copper nitrate.

4. The preparation method according to claim 3, characterized in that, The concentration of the doped metal salt solution is 0.001~0.1 mol / L; The dispersion contains Ba 2+ The concentration of vacant barium titanate is 0.01~1 mol / L; the concentration of the ammonia water is 1~10 mol / L.

5. The preparation method according to claim 1, characterized in that, The hydrothermal reaction is carried out at a temperature of 120~220 ℃ for a time of 6~24 h.

6. Modified barium titanate nanoparticles with strong piezoelectric effect prepared by the preparation method according to any one of claims 1-5.

7. The application of the modified nano-barium titanate with strong piezoelectric effect as described in claim 6 in the piezoelectric catalytic degradation of organic matter.

8. The application of the modified nano-barium titanate with strong piezoelectric effect as described in claim 6 in tumor therapeutic drugs.

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