阅读说明：本技术 一种可涂敷于磁性微型机器人表面的复合压电光催化剂及其制备方法和应用 (Composite piezoelectric photocatalyst capable of being coated on surface of magnetic micro-robot and preparation method and application thereof ) 是由 付比 胡程志 于 2021-07-05 设计创作，主要内容包括：本发明涉及一种可涂敷于磁性微型机器人表面的复合压电光催化剂及其制备方法和应用,所述复合压电光催化剂包括单晶结构的铁电材料和光电半导体材料形成的纳米复合纤维；所述纳米复合纤维的直径为400-800nm。本发明所述复合压电光催化剂具有较强的催化降解有机污染物能力,性质稳定,利于处理工业废水处理和环境修复,所述复合压电光催化剂还能用于磁性微型机器人表面的涂覆。(The invention relates to a composite piezoelectric photocatalyst capable of being coated on the surface of a magnetic micro-robot, a preparation method and application thereof, wherein the composite piezoelectric photocatalyst comprises a nano composite fiber formed by a ferroelectric material with a single crystal structure and a photoelectric semiconductor material; the diameter of the nano composite fiber is 400-800 nm. The composite piezoelectric photocatalyst has strong capability of catalyzing and degrading organic pollutants, has stable property, is beneficial to treating industrial wastewater and repairing environment, and can also be used for coating the surface of a magnetic micro-robot.)

1. A composite piezoelectric photocatalyst which can be coated on the surface of a magnetic micro-robot, is characterized in that the composite piezoelectric photocatalyst comprises a nano composite fiber formed by a ferroelectric material with a single crystal structure and a photoelectric semiconductor material;

the diameter of the nano composite fiber is 400-800 nm.

2. The composite piezoelectric photocatalyst applicable to the surface of a magnetic micro-robot according to claim 1, wherein the ferroelectric material comprises lead zirconate titanate and/or barium titanate;

preferably, the optoelectronic semiconductor material comprises titanium dioxide and/or zinc oxide.

3. The composite piezoelectric photocatalyst capable of being coated on the surface of a magnetic micro-robot as claimed in claim 1 or 2, wherein the molar ratio of the ferroelectric material and the photoelectric semiconductor material in the single crystal structure is 1 (8-12).

4. A method for preparing a composite piezoelectric photocatalyst capable of being coated on the surface of a magnetic micro-robot according to any one of claims 1 to 3, comprising the steps of:

(1) preparing a ferroelectric material with a single crystal structure by a hydrothermal method;

(2) preparing a precursor solution from a ferroelectric material with a single crystal structure, a preparation raw material of a photoelectric semiconductor material, a solvent and a high polymer material by a sol-gel method;

(3) and (3) carrying out electrostatic spinning on the precursor solution and then calcining to obtain the composite piezoelectric photocatalyst.

5. The process of claim 4, wherein the hydrothermal process of step (1) comprises the steps of:

mixing the preparation raw materials of the ferroelectric material, heating, post-treating and drying to obtain the ferroelectric material;

preferably, the raw material for preparing the ferroelectric material comprises any one or a combination of at least two of tetrabutyl titanate, titanium tetrafluoride, ammonia water, lead nitrate, zirconium oxychloride or titanium tetrachloride;

preferably, the means for heating comprises a forced air drying oven;

preferably, the heating temperature is 180-220 ℃;

preferably, the heating time is 36-48 h;

preferably, the post-treatment comprises two operations of washing and centrifugation;

preferably, the post-treated solvent comprises a combination of water and ethanol;

preferably, the temperature of the drying is 75-85 ℃;

preferably, the drying time is 20-30 h.

6. The method according to claim 4 or 5, wherein the polymer material in step (2) comprises any one or a combination of at least two of polyvinylpyrrolidone, polymethyl methacrylate, and polyvinyl alcohol;

preferably, the number average molecular weight of the polymer material is 30000-40000 g/mol;

preferably, the raw material for preparing the photoelectric semiconductor material comprises any one or a combination of at least two of metal salt, metal base or metal organic compound of the photoelectric semiconductor material;

preferably, the metal base comprises barium hydroxide;

preferably, the metal salt comprises any one of barium titanate, barium chloride or zinc chloride or a combination of at least two thereof;

preferably, the molar ratio of the ferroelectric material with the single crystal structure to the raw materials for preparing the photoelectric semiconductor material is 1 (8-12);

preferably, the mass ratio of the preparation raw materials of the photoelectric semiconductor material to the high polymer material is (8-12): 1.

7. The method according to any one of claims 4 to 6, wherein the step (3) further comprises a drying operation before the calcination;

preferably, the temperature of the drying is 100-140 ℃;

preferably, the drying time is 1-3 h;

preferably, the temperature of the calcination is 450-550 ℃;

preferably, the calcination time is 1.5-2.5 h.

8. The method according to any one of claims 4 to 7, characterized by comprising the steps of:

(1) reacting raw materials for preparing the ferroelectric material in a hydrothermal reaction kettle at the temperature of 180-220 ℃ for 36-48h by an air-blast drying box, then carrying out two-step post-treatment on a reactant by cleaning and centrifuging, and drying the post-treated reactant at the temperature of 75-85 ℃ for 20-30 h;

(2) preparing a precursor solution from a ferroelectric material with a single crystal structure, a preparation raw material of a photoelectric semiconductor material, a solvent and a high polymer material by a sol-gel method;

(3) and (3) drying the precursor solution for 1-3h at the temperature of 100-140 ℃ after electrostatic spinning, and then calcining for 1.5-2.5h at the temperature of 450-550 ℃ to obtain the composite piezoelectric photocatalyst.

9. A magnetic micro-robot having a surface provided with the composite piezoelectric photocatalyst according to any one of claims 1 to 3.

10. Use of a composite piezoelectric photocatalyst according to any one of claims 1-3 in industrial wastewater treatment.

Technical Field

The invention relates to the technical field of composite materials, in particular to a composite piezoelectric photocatalyst capable of being coated on the surface of a magnetic micro-robot, and a preparation method and application thereof.

Background

In recent years, the rapidly-developed industrial production has caused a serious problem of environmental pollution. Industrial wastewater containing organic pollutants such as highly toxic chemicals, synthetic dyes, drugs, and the like presents many challenges for environmental management and ecological restoration.

The piezoelectric catalyst generates spontaneous polarization under natural conditions, and the internal positive and negative charges are separated, so that the piezoelectric catalyst is a neutral electric dipole. The piezoelectric catalyst is strained under the action of stress, and the displacement of the center of positive and negative charges causes the change of internal polarization state, so that displacement polarization is formed. The positive and negative charges in the piezoelectric catalyst are separated by a built-in electric field generated by displacement polarization to form polarized charges. The built-in electric field intensity of the piezoelectric catalyst is regulated and controlled based on micro mechanical energy (water waves, vibration, noise and the like) dispersed in the external environment, high-density polarization charges are generated, hydroxyl radicals are formed, and then a series of redox reactions are initiated. Therefore, the piezoelectric catalyst can degrade organic pollutants under the action of periodic mechanical vibration, and is an advanced oxidation technology with great potential.

Meanwhile, the built-in electric field of the piezoelectric catalyst can drive photo-generated electrons and vacancies to move in opposite directions, so that the photocatalytic activity is improved. Therefore, the piezoelectric/semiconductor composite catalyst can promote the oxidation-reduction reaction under the synergistic action of ultrasonic vibration and light radiation, and achieves the purpose of promoting the catalytic degradation of organic pollutants. The piezoelectric/semiconductor composite material with excellent catalytic degradation performance is designed, prepared and synthesized, so that a new way is provided for environmental management and ecological restoration.

CN112044426A discloses a barium titanate/potassium niobate composite piezoelectric photocatalyst, a preparation method and an application thereof, and the disclosed barium titanate/potassium niobate composite piezoelectric photocatalyst is BaTiO with a particle size of 30-50nm₃The nanospheres are uniformly distributed on the prism-shaped KNbO₃And the stability is better, and the piezoelectric photocatalytic activity is excellent. The barium titanate/potassium niobate composite piezoelectric photocatalyst disclosed by the preparation method has the advantages of easily available raw materials, simple method process and convenience in operation. The application of the barium titanate/potassium niobate composite piezoelectric photocatalyst disclosed by the invention can improve the degradation rate of organic dye based on the piezoelectric effect and the photocatalytic effect.

CN110292940A publicationThe CdS/ZnO composite piezoelectric photocatalyst is prepared through synthesizing ZnO nano rods by a solvothermal method, and synthesizing the CdS/ZnO composite piezoelectric photocatalyst by taking the ZnO nano rods as precursors and performing chemical bath through electrostatic adsorption. The disclosed catalyst is a piezoelectric photocatalyst formed by compounding two CdS and ZnO with piezoelectric properties, a piezoelectric electric field is utilized to promote the separation of photo-generated carriers so as to improve the photocatalytic activity, the separation of the interior and the space of the photo-generated carriers is realized at the same time, the compounding of the photo-generated carriers is reduced, the utilization rate of solar energy is improved, and the piezoelectric photocatalytic rate reaches 5.477min^-1And the photocatalytic efficiency is 4 times that of CdS alone. The piezoelectric photocatalyst disclosed by the method has the advantages of easily available raw materials, simple preparation method process, convenience in operation and good stability of the composite material, and provides a feasible strategy for improving the photocatalytic performance.

In the prior art, although research is conducted on improving the treatment efficiency of industrial wastewater by compounding a piezoelectric catalyst and a photocatalyst to form the piezoelectric photocatalyst, the piezoelectric photocatalyst has relatively low efficiency or stability due to the limitations of material selection or process.

In view of the above, it is important to develop a piezoelectric photocatalyst having high piezoelectric photocatalytic efficiency and excellent stability.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a composite piezoelectric photocatalyst capable of being coated on the surface of a magnetic micro-robot, and a preparation method and application thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a composite piezoelectric photocatalyst that can be applied to the surface of a magnetic micro-robot, the composite piezoelectric photocatalyst comprising a nanocomposite fiber formed of a ferroelectric material of a single crystal structure and a photoelectric semiconductor material;

the diameter of the nano composite fiber is 400-800nm, such as 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm and the like.

The preparation raw materials of the composite piezoelectric photocatalyst adopt the ferroelectric material with the single crystal structure, and the ferroelectric material with the single crystal structure forms the composite piezoelectric photocatalyst which has a uniform built-in electric field and can obviously improve the performance of the piezoelectric photocatalyst; in addition, the diameter of the piezoelectric photocatalyst is 400-800nm, and most of ferroelectric materials and photoelectric semiconductor materials in the piezoelectric photocatalyst in the diameter range can be connected microscopically through crystal lattices, so that the performance of the piezoelectric photocatalyst is improved.

Preferably, the ferroelectric material comprises lead zirconate titanate and/or barium titanate.

Preferably, the optoelectronic semiconductor material comprises titanium dioxide and/or zinc oxide.

Preferably, the molar ratio of the ferroelectric material and the photoelectric semiconductor material of the single crystal structure is 1 (8-12), such as 1:8.5, 1:9, 1:9.5, 1:10, 1:10.5, 1:11, 1:11.5, and the like.

According to the invention, by adjusting the molar ratio of the ferroelectric material with a single crystal structure to the photoelectric semiconductor material to be 1 (8-12), the piezoelectric catalytic efficiency, the photocatalytic efficiency and the piezoelectric photocatalytic efficiency of the composite piezoelectric photocatalyst are high, and the composite piezoelectric photocatalyst has good stability.

In a second aspect, the present invention provides a method for preparing the composite piezoelectric photocatalyst of the first aspect, which can be coated on the surface of a magnetic micro-robot, the method comprising the following steps:

(1) preparing a ferroelectric material with a single crystal structure by a hydrothermal method;

(2) preparing a precursor solution from a ferroelectric material with a single crystal structure, a preparation raw material of a photoelectric semiconductor material, a solvent and a high polymer material by a sol-gel method;

(3) and (3) carrying out electrostatic spinning on the precursor solution and then calcining to obtain the composite piezoelectric photocatalyst.

The invention prepares the ferroelectric material with a single crystal structure by a hydrothermal method, then prepares a precursor solution by a sol-gel method, and calcines the precursor solution after electrostatic spinning to obtain the fibrous piezoelectric photocatalyst.

Preferably, the hydrothermal method in step (1) comprises the steps of:

and mixing the preparation raw materials of the ferroelectric material, heating, post-treating and drying to obtain the ferroelectric material.

Preferably, the raw material for preparing the ferroelectric material comprises any one or a combination of at least two of tetrabutyl titanate, titanium tetrafluoride, ammonia water, lead nitrate, zirconium oxychloride or titanium tetrachloride.

Preferably, the means for heating comprises a forced air drying oven. And (3) putting the preparation raw materials of the ferroelectric material into a hydrothermal reaction kettle, and heating the raw materials by an air-blast drying box.

Preferably, the heating temperature is 180-220 ℃, such as 185 ℃, 190 ℃, 195 ℃, 200 ℃, 205 ℃, 210 ℃, 215 ℃ and the like.

Preferably, the heating time is 36-48h, such as 38h, 40h, 42h, 44h, 46h, etc.

Preferably, the post-treatment comprises two operations of washing and centrifugation.

Preferably, the post-treated solvent comprises a combination of water and ethanol.

Preferably, the drying temperature is 75-85 degrees C, such as 76 degrees C, 77 degrees C, 78 degrees C, 79 degrees C, 80 degrees C, 81 degrees C, 82 degrees C, 83 degrees C, 84 degrees C.

Preferably, the drying time is 20-30h, such as 21h, 22h, 23h, 24h, 25h, 26h, 27h, 28h, 29h, and the like.

Preferably, the polymer material in step (2) includes any one of polyvinylpyrrolidone, polymethyl methacrylate or polyvinyl alcohol, or a combination of at least two of them.

Preferably, the number average molecular weight of the polymer material is 30000-40000g/mol, such as 32000g/mol, 34000g/mol, 36000g/mol, 38000g/mol, and the like.

Preferably, the raw material for preparing the photoelectric semiconductor material comprises any one or a combination of at least two of metal salt, metal base or metal organic compound of the photoelectric semiconductor material.

Preferably, the metal base comprises barium hydroxide.

Preferably, the metal salt comprises any one of barium titanate, barium chloride or zinc chloride or a combination of at least two thereof.

Preferably, the molar ratio of the ferroelectric material with single crystal structure to the raw materials for preparing the photoelectric semiconductor material is 1 (8-12), such as 1:8.5, 1:9, 1:9.5, 1:10, 1:10.5, 1:11, 1:11.5, etc.

Preferably, the mass ratio of the raw materials for preparing the photoelectric semiconductor material to the high polymer material is (8-12) to 1, such as 8.5:1, 9:1, 9.5:1, 10:1, 10.5:1, 11:1, 11.5:1, and the like.

Preferably, the step (3) further comprises a drying operation before the calcination.

Preferably, the drying temperature is 100-.

Preferably, the drying time is 1-3h, such as 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, and the like.

Preferably, the temperature of the calcination is 450-.

Preferably, the calcination is for a time of 1.5 to 2.5h, e.g., 1.6h, 1.8h, 2.0h, 2.2h, 2.4h, etc.

As a preferred technical scheme, the preparation method comprises the following steps:

(1) reacting raw materials for preparing the ferroelectric material in a hydrothermal reaction kettle at the temperature of 180-220 ℃ for 36-48h by an air-blast drying box, then carrying out two-step post-treatment on a reactant by cleaning and centrifuging, and drying the post-treated reactant at the temperature of 75-85 ℃ for 20-30 h;

(2) preparing a precursor solution from a ferroelectric material with a single crystal structure, a preparation raw material of a photoelectric semiconductor material, a solvent and a high polymer material by a sol-gel method;

(3) and (3) drying the precursor solution for 1-3h at the temperature of 100-140 ℃ after electrostatic spinning, and then calcining for 1.5-2.5h at the temperature of 450-550 ℃ to obtain the composite piezoelectric photocatalyst.

In a third aspect, the present invention provides a magnetic micro-robot having the composite piezoelectric photocatalyst according to the first aspect disposed on a surface thereof.

In a fourth aspect, the invention provides a use of the composite piezoelectric photocatalyst of the first aspect in industrial wastewater treatment.

Compared with the prior art, the invention has the following beneficial effects:

on one hand, the composite piezoelectric photocatalyst has the capability of catalyzing and degrading organic pollutants under the radiation of ultrasonic waves and ultraviolet light and the combined action of the ultrasonic waves and the ultraviolet light, has higher piezoelectric catalysis efficiency, photocatalysis efficiency and piezoelectric photocatalysis efficiency, is practical and simple, and is beneficial to industrial wastewater treatment and environmental remediation; on the other hand, the photocatalytic film is attached to the surface of the magnetic micro-robot to form a layer of piezoelectric photocatalytic film, and can be applied to the magnetic control robot.

Drawings

FIG. 1a is an X-ray diffraction pattern of a ferroelectric material of single crystal structure as described in example 1;

FIG. 1b is a Raman spectrum of a ferroelectric material of single crystal structure described in example 1;

FIG. 1c is a microstructure diagram of a ferroelectric material of single crystal structure described in example 1;

FIG. 1d is an enlarged view of a portion of the microstructure of FIG. 1 c;

FIG. 1e is a selected area electron diffraction pattern of a ferroelectric material of single crystal structure as described in example 1;

FIG. 1f is a high resolution transmission electron microscope image of a ferroelectric material of single crystal structure as described in example 1;

FIG. 1g is an enlarged view of a portion of FIG. 1 f;

FIG. 1h is a full electron micrograph of a ferroelectric material of single crystal structure described in example 1;

FIG. 2a is a transmission electron micrograph of the piezoelectric photocatalyst described in example 1;

FIG. 2b is a selected area electron diffraction pattern of the piezoelectric photocatalyst described in example 1;

FIG. 2c is a partial enlarged view of the piezoelectric photocatalyst according to example 1 taken by a transmission electron microscope

FIG. 2d is a high resolution transmission electron micrograph of the piezoelectric photocatalyst described in example 1;

FIG. 2e is a full electron view of a transmission electron microscope of the piezoelectric photocatalyst described in example 1;

FIG. 3 is a graph of the UV-VIS absorption spectrum of the piezoelectric photocatalyst under ultrasonic vibration according to example 1;

FIG. 4 is a graph of the UV-visible absorption spectrum of the piezoelectric photocatalyst of example 1 under UV radiation;

FIG. 5 is a graph of the UV-VIS absorption spectrum of the piezoelectric photocatalyst according to example 1 under the combined action of ultrasonic vibration and light irradiation;

Detailed Description

For the purpose of facilitating an understanding of the present invention, the present invention will now be described by way of examples. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

Example 1

This example provides a composite piezoelectric photocatalyst that can be applied to the surface of a magnetic micro-robot, which is a nanocomposite fiber (600 nm in diameter) formed of a ferroelectric material and a photoelectric semiconductor material of a single crystal structure (molar ratio of the two is 1: 9.8).

The preparation method of the composite piezoelectric photocatalyst comprises the following steps:

(1)8.5g of tetrabutyltitanate (97% pure, from Sigma-Aldrich) are dissolved in 20mL of ethanol, and 3.5mL of 25 wt.% ammonia, 7.0g of Ba (OH)₂·H₂Dissolving O (purity 98% purchased from Sigma-Aldrich) in 25mL of deionized water to obtain a barium hydroxide aqueous solution, mixing the two solutions, pouring the mixture into a 100mL hydrothermal reaction kettle, reacting at 200 ℃ for 48h, cooling the temperature of the hydrothermal reaction kettle to room temperature, repeatedly washing with water and ethanol, centrifuging to collect a product, and finally drying at 80 ℃ for 24h to obtain barium titanate particles (BaTiO)₃)；

(2) Preparation of BaTiO by sol-gel method₃/TiO₂PVP precursor solution: dissolving 0.7g of tetrabutyl titanate in 10mL of ethanol, mixing, stirring, clarifying and transparentizing, adding 50mg of single crystal barium titanate nanoparticles prepared by a hydrothermal method, and adding 6mg of polyvinylpyrrolidone (with a number average molecular weight of 40000g/mol, obtained from Yibaishun science and technology Limited company, Shenzhen, and having a brand number of K₃₀) Adding the solution into the mixed solution to prepare a spinning precursor solution;

(3) putting the precursor solution into a 10mL injector connected with a 21G stainless steel needle, taking an aluminum foil as a spinning receiving electrode, keeping the distance from the needle point to the receiving electrode at 12cm, controlling the spinning voltage at about 15kV, drying the precursor nanofiber obtained by spinning at 120 ℃ for 2 hours, and calcining at 500 ℃ for 2 hours to obtain BaTiO₃/TiO₂The composite nanofiber is the composite piezoelectric photocatalyst.

Example 2

The present example provides a composite piezoelectric photocatalyst that can be coated on the surface of a magnetic micro-robot, which is a nanocomposite fiber (400 nm in diameter) formed of a ferroelectric material and a photoelectric semiconductor material (molar ratio of the two is 1:8) in a single crystal structure.

The preparation method of the piezoelectric photocatalyst comprises the following steps:

(1)3.2g of lead nitrate, 3.2g of zirconium oxychloride and 3.2g of titanium tetrachloride (dissolved in 20mL of ethanol, 3.5mL of ammonia water with the mass percentage of 25 wt.% is added, and 7.0g of potassium hydroxide is dissolved in 25mL of deionized water to obtain a potassium hydroxide aqueous solution, the two solutions are mixed and poured into a 100mL hydrothermal reaction kettle, the mixture is reacted for 48 hours at 180 ℃, the temperature of the hydrothermal reaction kettle is reduced to room temperature, then the product is repeatedly washed and centrifuged by water and ethanol, and finally the product is dried for 30 hours at 75 ℃ to obtain lead zirconate titanate Particles (PZT) with a single crystal structure;

(2) preparing a PZT/ZnO/PMMA precursor solution by adopting a sol-gel method: 0.13g of zinc chloride is dissolved in 10mL of ethanol, and after the zinc chloride is mixed, stirred, clarified and transparent, 50mg of single crystal lead zirconate titanate nano particles prepared by a hydrothermal method are added, and 6mg of polymethyl methacrylate (the number average molecular weight of 30000g/mol, purchased from Beijing Vocko Biotechnology Ltd., trade name of 100EA) is added into the mixed solution to prepare a spinning precursor solution;

(3) and (2) putting the precursor solution into a 10mL injector connected with a 21G stainless steel needle, taking an aluminum foil as a spinning receiving electrode, keeping the distance from the needle point to the receiving electrode at 12cm, controlling the spinning voltage at about 15kV, drying the precursor nanofiber obtained by spinning at 100 ℃ for 3 hours, and calcining at 550 ℃ for 1.5 hours to obtain the PZT/ZnO composite nanofiber, namely the composite piezoelectric photocatalyst.

Example 3

The present example provides a composite piezoelectric photocatalyst that can be coated on the surface of a magnetic micro-robot, which is a nanocomposite fiber (800 nm in diameter) formed of a ferroelectric material and a photoelectric semiconductor material of a single crystal structure (molar ratio of the two is 1: 12).

The preparation method of the piezoelectric photocatalyst comprises the following steps:

(1)8.5g of tetrabutyltitanate (97% pure, from Sigma-Aldrich) are dissolved in 20mL of ethanol, and 3.5mL of 25 wt.% ammonia, 7.0g of Ba (OH)₂·H₂Dissolving O (purity 98% purchased from Sigma-Aldrich) in 25mL of deionized water to obtain a barium hydroxide aqueous solution, mixing the two solutions, pouring the mixture into a 100mL hydrothermal reaction kettle, reacting at 200 ℃ for 48h, cooling the temperature of the hydrothermal reaction kettle to room temperature, repeatedly washing with water and ethanol, centrifuging to collect a product, and finally drying at 80 ℃ for 24h to obtain barium titanate particles (BaTiO)₃)；

(2) Preparation of BaTiO by sol-gel method₃/TiO₂PVA precursor solution: dissolving 0.87g of tetrabutyl titanate in 10mL of ethanol, mixing, stirring, clarifying and transparentizing, adding 50mg of single-crystal barium titanate nanoparticles prepared by a hydrothermal method, and adding 6mg of polyvinyl alcohol (number average molecular weight of 35000g/mol, purchased from Shenzhen Yibaishun science and technology Limited, and brand number of 9002-89-5) into the mixed solution to prepare a spinning precursor solution;

(3) the precursor solution is filled into a 10mL injector connected with a 21G stainless steel needle, aluminum foil is used as a spinning receiving electrode, the distance from the needle point to the receiving electrode is kept at 12cm, the spinning voltage is controlled at about 15kV, and the precursor nanofiber obtained by spinning is obtainedDrying at 100 ℃ for 3 hours, calcining at 450 ℃ for 2.5 hours to obtain BaTiO₃/TiO₂The composite nanofiber is the composite piezoelectric photocatalyst.

Examples 4 to 5

Examples 4 to 5 are different from example 1 in that the composite piezoelectric photocatalyst was formed to have diameters of 400nm and 800nm, respectively, and spinning voltages of 10V and 18V, respectively, and the rest was the same as example 1.

Comparative example 1

The comparative example differs from example 1 in that the ferroelectric material is polycrystalline barium titanate, the piezoelectric photocatalyst is a nanocomposite fiber (diameter 600nm) formed of polycrystalline ferroelectric material (nano barium titanate, available from Shanghai Aladdin Biotechnology Ltd., CAS number: 12047-27-7, size less than 100nm) and photoelectric semiconductor material (molar ratio of the two is 1: 9.8).

The preparation method of the piezoelectric photocatalyst comprises the following steps:

(1) preparation of BaTiO by sol-gel method₃/TiO₂PVP precursor solution: dissolving 0.7g of tetrabutyl titanate in 10mL of ethanol, mixing, stirring, clarifying and transparentizing, adding 50mg of nano barium titanate, and adding 6mg of polyvinylpyrrolidone (with the number average molecular weight of 40000g/mol, purchased from Shenzhen Yibaishun science and technology Limited and under the brand number of K30) into the mixed solution to prepare a spinning precursor solution;

(2) putting the precursor solution into a 10mL injector connected with a 21G stainless steel needle, taking an aluminum foil as a spinning receiving electrode, keeping the distance from the needle point to the receiving electrode at 12cm, controlling the spinning voltage at about 15kV, drying the precursor nanofiber obtained by spinning at 120 ℃ for 2 hours, and calcining at 500 ℃ for 2 hours to obtain BaTiO₃/TiO₂And compounding the nano fiber to obtain the piezoelectric photocatalyst.

Comparative examples 2 to 3

Comparative examples 2 to 3 are different from example 1 in that the composite piezoelectric photocatalyst was formed to have diameters of 300nm and 900nm, respectively, and spinning voltages of 8V and 20V, respectively, and the rest was the same as example 1.

Performance testing

Examples 1-5 and comparative examples 1-3 were tested as follows:

(1) structural performance characterization of ferroelectric material of single crystal structure: carrying out X-ray diffraction, Raman spectrum test and transmission electron microscope test on the ferroelectric material with the single crystal structure;

(2) microstructure of piezoelectric photocatalyst: performing transmission electron microscope and electron diffraction on the piezoelectric photocatalyst;

(3) ultraviolet-visible light absorption spectrum analysis of piezoelectric photocatalyst: including ultrasonic vibration, ultraviolet radiation, and spectroscopic analysis of the combined effects of ultrasonic vibration and light radiation.

The test results are summarized in FIGS. 1-5.

On one hand, the composite piezoelectric photocatalyst has the capability of catalyzing and degrading organic pollutants under the combined action of ultrasonic vibration, ultraviolet radiation and the combined action, has higher piezoelectric catalysis efficiency, photocatalytic efficiency and piezoelectric photocatalysis efficiency, is practical and simple, and is beneficial to industrial wastewater treatment and environmental remediation.

As can be seen from the analysis of fig. 1, fig. 1a to fig. 1h show the microstructure and morphology characterization results of the ferroelectric material with single crystal structure in example 1, and the analysis shows that the ferroelectric material with single crystal structure is formed by the hydrothermal method of the present invention.

As can be seen from fig. 2, fig. 2a to 2e show the microstructure and morphology characterization results of the piezoelectric photocatalyst of example 1, and it can be seen from the figure that the diameter of the piezoelectric photocatalyst is about 600nm, in which a plurality of hydrothermal synthesized single-crystal barium titanate nanoparticles are embedded, wherein fig. 2d shows the contact surface of the single-crystal barium titanate nanoparticles to the titanium dioxide nanocrystals, and it can be seen that the (111) crystal plane of the barium titanate is closely connected to the (004) and (200) crystal planes of the titanium dioxide through crystal lattices.

As can be seen from the analysis of fig. 3-5, fig. 3-5 are uv-vis absorption spectra analysis of the piezoelectric photocatalyst described in example 1, and the degradation rate of organic pollutants by the piezoelectric photocatalyst under the conditions of ultrasonic vibration, light radiation and their synergistic effect are studied respectively. The concentration of organic pollutants is measured by an ultraviolet-visible light absorption analyzer, and the periodic change of the organic pollutants is compared, so that the experimental result shows that the piezoelectric photocatalysis performance of the composite piezoelectric photocatalyst is superior to that of piezoelectric catalysis and photocatalysis.

As can be seen from the analysis of comparative example 1 and example 1, the performance of comparative example 1 is inferior to that of example 1, and the performance of the composite piezoelectric photocatalyst formed by the ferroelectric material with a single crystal structure is proved to be better.

As can be seen from the analysis of comparative examples 2-3 and examples 4-5, comparative examples 2-3 do not perform as well as examples 4-5, demonstrating that piezoelectric photocatalysts perform better in the diameter range of 400nm to 800 nm.

The applicant states that the present invention is illustrated in detail by the above examples, but the present invention is not limited to the above detailed methods, i.e. it is not meant that the present invention must rely on the above detailed methods for its implementation. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.