Piezoelectric catalytic material and preparation method thereof

Abstract

The invention discloses a piezoelectric catalytic material and a preparation method thereof, and particularly relates to the field of piezoelectric catalytic materials, the piezoelectric catalytic material comprises a flexible piezoelectric matrix component, a polarization enhancement component, a free radical activation and electron capture component and a film forming component; by constructing a composite system synergistically enhanced by a flexible polymer matrix and a high-polarization functional filler, the piezoelectric catalytic activity of the material is improved, and the response capability to low-frequency mechanical energy is enhanced, so that the problems that the existing inorganic piezoelectric ceramic is high in brittleness and insufficient in flexibility, and the existing PVDF material is low in natural polarization phase content, weak in carrier migration capability and poor in mechanical property are solved. The catalytic efficiency is not high; and the energy conversion is insufficient. The material shows excellent capability of converting mechanical energy into chemical energy under natural mechanical excitation conditions such as low-frequency water flow, realizes efficient catalytic degradation of organic pollutants, and has good environmental adaptability and stability; the practical application requirements of the fields of green energy recovery and environmental governance on flexible, durable and self-energized catalytic materials can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of piezoelectric catalytic materials, and more particularly to a piezoelectric catalytic material and a preparation method thereof. Background Art

[0002] In the field of piezoelectric catalysis, existing technologies mainly rely on inorganic piezoelectric ceramic materials. Although they have high piezoelectric performance and energy conversion efficiency, their inherent brittleness, low flexibility, and processing difficulties make the materials have obvious limitations in complex mechanical environments and flexible structural applications. They are difficult to meet the requirements for material stability and adaptability in low-frequency energy scenarios such as actual water treatment.

[0003] To overcome the rigidity defects of inorganic materials, flexible polymer materials, particularly polyvinylidene fluoride (PVDF), have been proposed as alternatives due to their light weight, good flexibility, and strong biocompatibility. However, existing PVDF materials are limited by insufficient content of the natural polarization phase β, low piezoelectric properties, and limited carrier mobility. As a result, their catalytic efficiency and energy conversion capacity under natural energy driving conditions such as low-frequency vibration or water flow are far from meeting the requirements of practical applications.

[0004] At the same time, current piezoelectric catalytic systems mostly rely on high-frequency mechanical energy driving methods such as ultrasonic vibration, which is significantly mismatched with the low-frequency, low-energy mechanical excitations commonly found in the environment. This limits the engineering application potential of piezoelectric catalytic technology in the fields of green energy recovery and environmental pollution control.

[0005] Based on the development status and limitations of the above existing technologies, it can be seen that how to further improve the piezoelectric catalytic activity and enhance the response capability to low-frequency mechanical energy on the basis of achieving material flexibility has become a key issue restricting the practical application of piezoelectric catalytic technology. Summary of the Invention

[0006] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a piezoelectric catalytic material and a preparation method thereof, which improves the piezoelectric catalytic activity and enhances the low-frequency mechanical energy response capability by constructing a composite system synergistically reinforced by a flexible polymer matrix and a high-polarization functional filler, so as to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a piezoelectric catalytic material, comprising a composite system of the following components in parts by weight:

[0008] A flexible piezoelectric matrix component, in an amount of 80-120 parts by weight, wherein the flexible piezoelectric matrix component is used to construct a flexible skeleton and provide a basic piezoelectric response;

[0009] A polarization enhancement component, in an amount of 20-40 parts by weight, which is used to enhance the interface polarization effect and improve the carrier migration efficiency;

[0010] A free radical activation and electron capture component, in an amount of 5 to 15 parts by weight, wherein the free radical activation and electron capture component is used to promote free radical generation and optimize electron capture channels;

[0011] The film-forming component has a weight ratio of 5 to 15 parts, and is used to optimize the film-forming performance and environmental stability of the composite material.

[0012] In a preferred embodiment, the flexible piezoelectric matrix component is configured in the following weight ratio:

[0013] Polyvinylidene fluoride (PVDF), 95 parts, with a β-phase crystallinity of not less than 70%, a molecular weight in the range of 400,000–600,000 g / mol, and a melting point of 160–170°C;

[0014] Polyvinylpyrrolidone (PVP), 3 parts, molecular weight 40,000–60,000 g / mol, used to promote polarized chain segment orientation;

[0015] Fluorinated polyacrylate (FPAA), 2 parts, average particle size less than 100 nm, for optimizing tensile strength.

[0016] In a preferred embodiment, the polarization enhancement component is configured in the following weight ratio:

[0017] Iron oxide (Fe3O4) nanoparticles, 50 parts, particle size controlled at 50–80 nm, magnetic saturation intensity not less than 60 emu / g;

[0018] Bismuth ferrite (BiFeO3) nanoparticles, 25 parts, monoclinic, 40–60 nm in size, with antiferroelectric properties and a dielectric constant (relative permittivity) greater than 300;

[0019] Molybdenum disulfide (MoS2) flakes, 15 parts, with a layer thickness less than 10 nm, a lateral dimension greater than 500 nm, and a conductivity greater than 500 S / cm;

[0020] Ti3C2MXene flake material, 10 parts, thickness 2–5 nm, interlayer spacing not less than 1 nm, specific surface area greater than 100 m 2 / g;

[0021] Aminosilane (KH-550) surface modifier, added in an amount of 3% of the total weight of the inorganic components, is used to improve the dispersion uniformity and interface bonding strength of the filler in the polymer matrix.

[0022] In a preferred embodiment, the free radical activation and electron capture components are configured in the following weight ratios:

[0023] Graphitic carbon nitride (g-C3N4), 50 parts, flake thickness 5–10 nm, surface area greater than 60 m 2 / g, and the C / N molar ratio was controlled at 0.65–0.7;

[0024] Nitrogen-doped graphene (N-Graphene), 30 parts, nitrogen doping amount is 5–8 at%, the sheet thickness is less than 5 nm, and the surface charge mobility is higher than 1000 cm 2 / V·s;

[0025] Molybdenum disulfide (MoS2), 20 parts, crystallinity greater than 90%, electron mobility greater than 200 cm 2 / V·s, and has the characteristics of van der Waals heterojunction structure.

[0026] In a preferred embodiment, the film-forming components are configured in the following weight ratios:

[0027] 70 parts of waterborne polyurethane (PU) dispersion, with a solid content of 30 ± 2 wt% and a particle size of less than 80 nm;

[0028] Irganox 1010 antioxidant, 20 parts, with a thermal decomposition temperature above 350°C and a free radical capture capacity greater than 90%;

[0029] Dioctyl phthalate (DOP), 10 parts, with a molecular weight in the range of 390–410 g / mol and a boiling point above 380°C, is used to regulate the interaction between chain segments within the material and adjust the Young's modulus to the range of 100–300 MPa.

[0030] A method for preparing a piezoelectric catalytic material:

[0031] S1: Preparation of flexible piezoelectric substrate precursor solution:

[0032] Polyvinylidene fluoride (PVDF), polyvinyl pyrrolidone (PVP), and fluorinated polyacrylate (FPAA) were added to N,N-dimethylformamide (DMF) in a weight ratio of 95:3:2 to control the solution mass fraction to 10–15%. The solution was magnetically stirred at room temperature for 360 minutes until no visible precipitate was present, thereby obtaining a precursor solution.

[0033] S2: Preparation of polarization-enhanced composite component dispersion:

[0034] Iron oxide (Fe3O4) nanoparticles, bismuth ferrite (BiFeO3) nanoparticles, molybdenum disulfide (MoS2) sheets, and Ti3C2MXene sheet materials were mixed in anhydrous ethanol at a weight ratio of 50:25:15:10, and an aminosilane (KH-550) surface modifier (3% by weight of the total weight of the inorganic components) was added. The mixture was ultrasonically treated for 1800 seconds to complete the dispersion.

[0035] S3: Preparation of dispersion of composite components of free radical activation and electron capture:

[0036] Graphite carbon nitride (g-C3N4), nitrogen-doped graphene (N-Graphene) and molybdenum disulfide (MoS2) were mixed in a weight ratio of 50:30:20, added to isopropanol, and ultrasonicated for 3600 seconds to complete dispersion.

[0037] S4: Preparation of film-forming aid dispersion:

[0038] A water-based polyurethane (PU) dispersion, Irganox 1010 antioxidant, and dioctyl phthalate (DOP) were mixed in a weight ratio of 70:20:10, and a water-alcohol mixed solvent was added. The mixture was mechanically stirred for 240 minutes to prepare a film-forming aid dispersion.

[0039] S5: Preparation of composite piezoelectric catalytic slurry:

[0040] The flexible piezoelectric matrix precursor solution, polarization enhancement composite component dispersion, free radical activation and electron capture composite dispersion and film-forming aid dispersion were added to a high-speed disperser according to a preset weight ratio and stirred at 500 rpm for 300 minutes. After completion, the mixture was placed under vacuum conditions with a pressure not higher than -0.1 MPa and degassed for 60 minutes to obtain a composite slurry.

[0041] In a preferred embodiment, S6: film forming and drying:

[0042] The composite piezoelectric catalytic slurry was coated on the surface of the pretreated substrate by spin coating, with the spin coating speed set to 1000–3000 rpm and the spin coating time set to 30–60 seconds. After the spin coating was completed, the sample was placed in a vacuum oven and dried at 80°C for 120 minutes, then heated to 120°C and continued to be dried for 480 minutes to prepare a dry piezoelectric catalytic film layer.

[0043] In a preferred embodiment, S7: polarization treatment:

[0044] The dried piezoelectric catalytic film layer was placed in a high-voltage polarization device, a DC electric field strength of 5–10 kV / cm was applied, the polarization temperature was controlled at 80–100°C, and the polarization time was set to 1800 seconds to complete the polarization treatment;

[0045] S8: Film stripping and collection:

[0046] The polarized piezoelectric catalytic film is peeled off from the substrate surface, cooled to room temperature, and cut into a desired size to obtain a finished piezoelectric catalytic film.

[0047] Technical effects and advantages of the present invention:

[0048] 1. The present invention constructs a flexible PVDF-based piezoelectric catalytic material and combines it with a multi-component composite system of Fe3O4, BiFeO3 and MXene to enhance the material's response to low-frequency mechanical energy, thereby solving the problems of existing inorganic piezoelectric materials such as high brittleness, insufficient flexibility and poor environmental adaptability.

[0049] 2. By introducing highly polarizable fillers and regulating the β-phase crystallinity, the carrier migration efficiency is improved, the internal charge separation is enhanced, and the free radical generation capacity in the piezoelectric catalytic reaction is significantly improved, thereby promoting the efficient degradation of water pollutants;

[0050] 3. A flexible polymer matrix and inorganic functional particles are used to collaboratively construct a composite structure, balancing mechanical flexibility and electrical stability, and achieving a stable catalytic degradation effect under environmental stimulation conditions such as low-frequency water flow;

[0051] 4. By optimizing the film-making process and polarization treatment steps, the surface density and adhesion of the film layer are improved, the risk of film peeling and mechanical fatigue in the working environment is reduced, and the long-term reliability of the material is enhanced;

[0052] 5. Design free radical activation and electron capture composite components to enhance the electron transfer process in the reaction path, effectively control the toxicity level of degradation intermediates, and promote the green and safe reaction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0055] Refer to the instruction manual Figure 1 The present invention provides a piezoelectric catalytic material and a preparation method thereof, comprising:

[0056] Example 1: In this example, a piezoelectric catalytic material was prepared according to the following steps:

[0057] S1: Preparation of flexible piezoelectric substrate precursor solution:

[0058] Take 95 parts of polyvinylidene fluoride (PVDF), wherein the PVDF has a β-phase crystallinity of not less than 70%, a molecular weight within the range of 400,000–600,000 g / mol, and a melting point of 160–170°C; take 3 parts of polyvinyl pyrrolidone (PVP), wherein the molecular weight of polyvinyl pyrrolidone (PVP) is 40,000–60,000 g / mol; and take 2 parts of fluorinated polyacrylate (FPAA), wherein the average particle size of the FPAA is less than 100 nm;

[0059] The above components were mixed in a weight ratio of 95:3:2 and added to N,N-dimethylformamide (DMF) to control the solution mass fraction to 10–15%.

[0060] At room temperature (25±2°C), a magnetic stirrer was used to stir at 500 rpm for 360 minutes until the solution became transparent and no precipitate was visible, thereby obtaining a flexible piezoelectric matrix precursor solution;

[0061] S2: Preparation of polarization-enhanced composite component dispersion:

[0062] Take 50 parts of iron oxide (Fe3O4) nanoparticles, with a particle size of 50-80nm and a magnetic saturation intensity of not less than 60emu / g; take 25 parts of bismuth ferrite (BiFeO3) nanoparticles, monoclinic, with a particle size of 40-60nm, with anti-ferroelectric properties and a relative dielectric constant greater than 300; take 15 parts of molybdenum disulfide (MoS2) sheets, with a layer thickness of less than 10nm, a lateral size greater than 500nm, and a conductivity greater than 500S / cm; take 10 parts of Ti3C2MXene sheet material, with a thickness of 2-5nm, an interlayer spacing of not less than 1nm, and a specific surface area greater than 100m 2 / g;

[0063] The above components were mixed in anhydrous ethanol in a weight ratio of 50:25:15:10, and then aminosilane (KH-550) surface modifier was added after mixing. The amount of KH-550 added was 3% of the total weight of the inorganic components.

[0064] Ultrasonic treatment was performed with a frequency of 40 kHz, a power of 500 W, and a treatment time of 1800 seconds to prepare a polarization-enhanced composite component dispersion.

[0065] S3: Preparation of dispersion of composite components of free radical activation and electron capture:

[0066] Take 50 parts of graphite carbon nitride (g-C3N4), the thickness of the sheet is 5-10nm, and the specific surface area is greater than 60m 2 / g, the C / N molar ratio is controlled at 0.65–0.7; 30 parts of nitrogen-doped graphene (N-Graphene) are taken, the nitrogen doping amount is 5–8at%, the sheet thickness is less than 5nm, and the surface charge mobility is higher than 1000cm 2 / V·s; Take 20 parts of molybdenum disulfide (MoS2), with a crystallinity greater than 90% and an electron migration rate greater than 200cm 2 / V·s, and has the characteristics of van der Waals heterojunction structure;

[0067] The above components were mixed in a weight ratio of 50:30:20, added to isopropyl alcohol, and treated with ultrasound at a frequency of 40 kHz, a power of 500 W, and a treatment time of 3600 seconds to prepare a free radical activation and electron capture composite dispersion.

[0068] S4: Preparation of film-forming aid dispersion:

[0069] 70 parts of a waterborne polyurethane (PU) dispersion having a solid content of 30 ± 2 mass percent and a particle size of less than 80 nm are prepared; 20 parts of an Irganox 1010 antioxidant having a thermal decomposition temperature greater than 350°C and a free radical capture capacity greater than 90% are prepared; and 10 parts of dioctyl phthalate (DOP) having a molecular weight within the range of 390–410 g / mol and a boiling point greater than 380°C are prepared.

[0070] The above components were mixed in a weight ratio of 70:20:10, added to a water-alcohol (mass ratio 1:1) mixed solvent, and stirred at 400 rpm using a mechanical stirrer for 240 minutes to prepare a film-forming aid dispersion;

[0071] S5: Preparation of composite piezoelectric catalytic slurry:

[0072] The flexible piezoelectric matrix precursor solution, the polarization enhancement composite component dispersion, the free radical activation and electron capture composite dispersion and the film-forming aid dispersion are mixed in a weight ratio of 100:30:10:10;

[0073] A high-speed disperser was used to stir the mixture at 500 rpm for 300 minutes. After the stirring was completed, the slurry was placed in a vacuum drying oven and subjected to a pressure of -0.1 MPa for degassing for 60 minutes to obtain a composite piezoelectric catalytic slurry.

[0074] S6: Film forming and drying:

[0075] The composite piezoelectric catalytic slurry was applied to the surface of the cleaned and dried polyester substrate by spin coating, with the spin coating speed set to 2000 rpm and the spin coating time set to 45 seconds;

[0076] After the spin coating is completed, the film layer is placed in a vacuum oven and first dried at 80°C for 120 minutes, then heated to 120°C and dried for another 480 minutes to obtain a dry piezoelectric catalytic film layer;

[0077] S7: Polarization treatment:

[0078] The dried piezoelectric catalytic film layer was placed in a high-voltage polarization device and a DC electric field was applied. The electric field strength was set to 7 kV / cm, the polarization temperature was set to 90°C, and the polarization time was set to 1800 seconds to complete the polarization treatment.

[0079] S8: Film stripping and collection:

[0080] The polarized piezoelectric catalytic film was peeled off from the substrate surface, cooled to room temperature, and cut into a size of 50 mm×50 mm to obtain a finished piezoelectric catalytic film material.

[0081] Example 2:

[0082] Based on Example 1, the weight proportions of the flexible piezoelectric matrix component, the polarization enhancement component, the free radical activation and electron capture component, and the film-forming component were adjusted to 80 parts, 20 parts, 5 parts, and 5 parts, respectively;

[0083] The selection of other components, component performance parameters, preparation process flow and process parameters are the same as those in Example 1.

[0084] Example 3:

[0085] Based on Example 1, the weight proportions of the flexible piezoelectric matrix component, the polarization enhancement component, the free radical activation and electron capture component, and the film-forming component were adjusted to 120 parts, 40 parts, 15 parts, and 15 parts, respectively;

[0086] The selection of other components, component performance parameters, preparation process flow and process parameters are the same as those in Example 1.

[0087] Example 4:

[0088] On the basis of Example 1, the weight fraction of bismuth ferrite (BiFeO3) nanoparticles in the polarization enhancement component was adjusted to 30 parts, the weight fraction of molybdenum disulfide (MoS2) flakes was adjusted to 10 parts, the weight fraction of iron oxide (Fe3O4) nanoparticles was adjusted to 45 parts, and the Ti3C2MXene flake material remained unchanged at 10 parts;

[0089] The selection of other components, performance parameters, preparation process flow and process parameters are the same as those in Example 1.

[0090] Example 5:

[0091] On the basis of Example 1, the weight proportions of nitrogen-doped graphene (N-Graphene) in the radical activation and electron capture component were adjusted to 40 parts, graphite phase carbon nitride (g-C3N4) was adjusted to 40 parts, and molybdenum disulfide (MoS2) remained unchanged at 20 parts;

[0092] The selection of other components, performance parameters, preparation process flow and process parameters are the same as those in Example 1.

[0093] Example 6:

[0094] On the basis of Example 1, dibutyl phthalate (DBP) was used to replace dioctyl phthalate (DOP) in the film-forming aid dispersion, and the other additive ratios and performance parameters remained unchanged;

[0095] The selection of other components, performance parameters, preparation process flow and process parameters are the same as those in Example 1.

[0096] Example 7:

[0097] On the basis of Example 1, the addition ratio of polyvinyl pyrrolidone (PVP) in the flexible piezoelectric matrix component was adjusted to 5 parts, the ratio of fluorinated polyacrylate (FPAA) was adjusted to 5 parts, and the corresponding ratio of polyvinylidene fluoride (PVDF) was adjusted to 90 parts;

[0098] The selection of other components, performance parameters, preparation process flow and process parameters are the same as those in Example 1.

[0099] Example 8:

[0100] On the basis of Example 1, the spin coating speed was adjusted to 3000 rpm, the spin coating time was adjusted to 30 seconds, and the other component selections, performance parameters and process parameters were the same as those in Example 1.

[0101] Comparative Example 1:

[0102] Compared with Example 1, no polarization enhancing component is added, that is, iron oxide (Fe3O4) nanoparticles, bismuth ferrite (BiFeO3) nanoparticles, molybdenum disulfide (MoS2) flakes and Ti3C2MXene flake materials are not added, and the selection of other components, performance parameters and process parameters are the same as those in Example 1.

[0103] Comparative Example 2:

[0104] Compared with Example 1, no free radical activation and electron capture components are added, that is, graphite phase carbon nitride (g-C3N4), nitrogen-doped graphene (N-Graphene) and molybdenum disulfide (MoS2) are not added, and the selection of other components, performance parameters and process parameters are the same as those in Example 1.

[0105] Comparative Example 3:

[0106] Compared with Example 1, no polarization treatment is performed, that is, the polarization step S7 is omitted, and the selection of other components, performance parameters and process parameters are the same as those in Example 1.

[0107] Table 1: Piezoelectric catalytic material performance test results

[0108] Sample number <![CDATA[压电系数D 33 (pC / N)]]> Tetracycline degradation rate (%) Free radical signal intensity (au) Example 1 42.5 92.3 285 Example 2 39.8 88.1 260 Example 3 45.2 94.7 300 Example 4 41.7 91.2 278 Example 5 43.3 93 290 Example 6 42 91.5 282 Example 7 40.5 89.7 270 Example 8 44 93.5 295 Comparative Example 1 25.2 65.8 190 Comparative Example 2 28.5 68.4 200 Comparative Example 3 30.1 71.2 210

[0109] Table 2: Effect of ratio changes on piezoelectric response

[0110] Sample number Flexible substrate quantity (parts) Polarization enhancement component number (parts) piezoelectric coefficient D 33 (pC / N) Example 2 80 20 39.8 Example 1 100 30 42.5 Example 3 120 40 45.2 Comparative Example 1 100 0 25.2 Comparative Example 3 100 30 30.1

[0111] Table 3: Correspondence between free radical enhancement and catalytic activity

[0112]

[0113]

[0114] Table 4: Relationship between polarization treatment and material properties

[0115] Sample number Whether polarization treatment <![CDATA[压电系数D 33 (pC / N)]]> Tetracycline degradation rate (%) Example 1 yes 42.5 92.3 Example 3 yes 45.2 94.7 Example 8 yes 44 93.5 Comparative Example 3 no 30.1 71.2

[0116] Table 5: Test results of catalytic reaction characteristics of piezoelectric catalytic materials

[0117] Sample number Degradation reaction rate constant k (min -1 )]]> Surface roughness Ra (nm) Film adhesion (N / m) Example 1 0.043 88 18.5 Example 2 0.039 92 17.8 Example 3 0.047 85 19.1 Example 4 0.042 89 18.2 Example 5 0.045 86 18.7 Example 6 0.043 87 18.4 Example 7 0.04 91 17.9 Example 8 0.046 86 18.8 Comparative Example 1 0.021 105 14.5 Comparative Example 2 0.024 102 14.9 Comparative Example 3 0.027 100 15.2

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A piezoelectric catalytic material, characterized in that: The composite system comprises the following components in proportion by weight: A flexible piezoelectric matrix component, in an amount of 80-120 parts by weight, wherein the flexible piezoelectric matrix component is used to construct a flexible skeleton and provide a basic piezoelectric response; A polarization enhancement component, in an amount of 20-40 parts by weight, which is used to enhance the interface polarization effect and improve the carrier migration efficiency; A free radical activation and electron capture component, in an amount of 5 to 15 parts by weight, wherein the free radical activation and electron capture component is used to promote free radical generation and optimize electron capture channels; The film-forming component has a weight ratio of 5 to 15 parts, and is used to optimize the film-forming performance and environmental stability of the composite material.

2. The piezoelectric catalytic material according to claim 1, characterized in that: The flexible piezoelectric matrix components are configured in the following weight ratios: Polyvinylidene fluoride (PVDF), 95 parts, with a β-phase crystallinity of not less than 70%, a molecular weight in the range of 400,000–600,000 g / mol, and a melting point of 160–170°C; Polyvinylpyrrolidone (PVP), 3 parts, molecular weight 40,000–60,000 g / mol, used to promote polarized chain segment orientation; Fluorinated polyacrylate (FPAA), 2 parts, average particle size less than 100 nm, for optimizing tensile strength.

3. The piezoelectric catalytic material according to claim 2, characterized in that: The polarization enhancement component is configured in the following weight ratio: Iron oxide (Fe3O4) nanoparticles, 50 parts, particle size controlled at 50–80 nm, magnetic saturation intensity not less than 60 emu / g; Bismuth ferrite (BiFeO3) nanoparticles, 25 parts, monoclinic, 40–60 nm in size, with antiferroelectric properties and a dielectric constant (relative permittivity) greater than 300; Molybdenum disulfide (MoS2) flakes, 15 parts, with a layer thickness less than 10 nm, a lateral dimension greater than 500 nm, and a conductivity greater than 500 S / cm; Ti3C2MXene sheet material, 10 parts, thickness of 2-5nm, interlayer spacing of not less than 1nm, specific surface area greater than 100m 2 / g; Aminosilane (KH-550) surface modifier, added in an amount of 3% of the total weight of the inorganic components, is used to improve the dispersion uniformity and interface bonding strength of the filler in the polymer matrix.

4. The piezoelectric catalytic material according to claim 3, characterized in that: The free radical activation and electron capture components are configured in the following weight ratios: Graphitic carbon nitride (g-C3N4), 50 parts, flake thickness 5–10 nm, surface area greater than 60 m 2 / g, and the C / N molar ratio was controlled at 0.65–0.7; Nitrogen-doped graphene (N-Graphene), 30 parts, nitrogen doping amount is 5–8 at%, the sheet thickness is less than 5 nm, and the surface charge mobility is higher than 1000 cm 2 / V·s; Molybdenum disulfide (MoS2), 20 parts, crystallinity greater than 90%, electron mobility greater than 200 cm 2 / V·s, and has the characteristics of van der Waals heterojunction structure.

5. The piezoelectric catalytic material according to claim 4, characterized in that: The film-forming components are configured in the following weight ratios: 70 parts of waterborne polyurethane (PU) dispersion, with a solid content of 30 ± 2 wt% and a particle size of less than 80 nm; Irganox 1010 antioxidant, 20 parts, with a thermal decomposition temperature above 350°C and a free radical capture capacity greater than 90%; Dioctyl phthalate (DOP), 10 parts, with a molecular weight in the range of 390–410 g / mol and a boiling point above 380°C, is used to regulate the interaction between chain segments within the material and adjust the Young's modulus to the range of 100–300 MPa.

6. A method for preparing a piezoelectric catalytic material, comprising applying the piezoelectric catalytic material according to claim 5, characterized in that: S1: Preparation of flexible piezoelectric substrate precursor solution: Polyvinylidene fluoride (PVDF), polyvinyl pyrrolidone (PVP), and fluorinated polyacrylate (FPAA) were added to N,N-dimethylformamide (DMF) in a weight ratio of 95:3:2 to control the solution mass fraction to 10–15%. The solution was magnetically stirred at room temperature for 360 minutes until no visible precipitate was present, thereby obtaining a precursor solution. S2: Preparation of polarization-enhanced composite component dispersion: Iron oxide (Fe3O4) nanoparticles, bismuth ferrite (BiFeO3) nanoparticles, molybdenum disulfide (MoS2) sheets, and Ti3C2MXene sheet materials were mixed in anhydrous ethanol at a weight ratio of 50:25:15:10, and an aminosilane (KH-550) surface modifier (3% by weight of the total weight of the inorganic components) was added. The mixture was ultrasonically treated for 1800 seconds to complete the dispersion. S3: Preparation of dispersion of composite components of free radical activation and electron capture: Graphite carbon nitride (g-C3N4), nitrogen-doped graphene (N-Graphene) and molybdenum disulfide (MoS2) were mixed in a weight ratio of 50:30:20, added to isopropanol, and ultrasonicated for 3600 seconds to complete dispersion. S4: Preparation of film-forming aid dispersion: A water-based polyurethane (PU) dispersion, Irganox 1010 antioxidant, and dioctyl phthalate (DOP) were mixed in a weight ratio of 70:20:10, and a water-alcohol mixed solvent was added. The mixture was mechanically stirred for 240 minutes to prepare a film-forming aid dispersion. S5: Preparation of composite piezoelectric catalytic slurry: The flexible piezoelectric matrix precursor solution, polarization enhancement composite component dispersion, free radical activation and electron capture composite dispersion and film-forming aid dispersion were added to a high-speed disperser according to a preset weight ratio and stirred at 500 rpm for 300 minutes. After completion, the mixture was placed under vacuum conditions with a pressure not higher than -0.1 MPa and degassed for 60 minutes to obtain a composite slurry.

7. The piezoelectric catalytic material and preparation method thereof according to claim 6, characterized in that: Also includes: S6: Film forming and drying: The composite piezoelectric catalytic slurry was coated on the surface of the pretreated substrate by spin coating, with the spin coating speed set to 1000–3000 rpm and the spin coating time set to 30–60 seconds. After the spin coating was completed, the sample was placed in a vacuum oven and dried at 80°C for 120 minutes, then heated to 120°C and continued to be dried for 480 minutes to prepare a dry piezoelectric catalytic film layer.

8. The piezoelectric catalytic material and preparation method thereof according to claim 7, characterized in that: Also includes: S7: Polarization treatment: The dried piezoelectric catalytic film layer was placed in a high-voltage polarization device, a DC electric field strength of 5–10 kV / cm was applied, the polarization temperature was controlled at 80–100°C, and the polarization time was set to 1800 seconds to complete the polarization treatment; S8: Film stripping and collection: The polarized piezoelectric catalytic film is peeled off from the substrate surface, cooled to room temperature, and cut into a desired size to obtain a finished piezoelectric catalytic film.

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