Piezoelectric electro-catalysis composite material slurry and piezoelectric electro-catalysis device

Abstract

The invention relates to the technical field of photocatalytic materials, in particular to piezoelectric electro-catalysis composite material slurry and a piezoelectric electro-catalysis device. The piezoelectric electro-catalysis composite material slurry is prepared from the following components in percentage by weight: 10-20% of bismuth ferrite, 10-20% of titanium dioxide, 10-20% of titanium dioxide, 10-20% of titanium dioxide and the balance of water, 30 to 50% of a bismuth ferrite-based piezoelectric composite material; 1-5% of a dispersant; 0.5-3% of a binder; and the balance of solvent. The piezoelectric electro-catalysis composite material slurry formed by mixing the bismuth ferrite-based piezoelectric composite material, the bismuth ferrite, the dispersing agent and the binding agent according to a certain weight percentage can construct a specific heterojunction, and the piezoelectric electro-catalysis efficiency is effectively improved under the synergistic effect.

Description

Technical Field

[0001] The present application belongs to the technical field of photocatalytic materials, and in particular relates to a piezoelectric photocatalytic composite material slurry and a piezoelectric photocatalytic device. Background Art

[0002] Photocatalysis, as a technology that uses light energy to drive catalytic reactions, plays an important role and has great potential in alleviating energy crises and controlling environmental pollution. Its principle is to use light energy to stimulate the generation of electron-hole pairs on the catalyst surface, thereby promoting chemical reactions. In order to further improve the photocatalytic effect, piezoelectric photocatalysis technology came into being.

[0003] Piezoelectric photocatalysis technology combines the piezoelectric effect and the principle of photocatalysis, and has important scientific significance and application prospects. The piezoelectric effect causes charge separation in the catalytic material by applying mechanical pressure, thereby regulating the transmission path of photogenerated carriers and improving the photocatalytic efficiency. Combining the piezoelectric effect with photocatalysis can further improve the catalytic performance of photocatalytic materials and expand their application range.

[0004] As an emerging piezoelectric photocatalyst, bismuth ferrite (BiFeO3, BFO) plays an important role in the field of piezoelectric photocatalysis due to its special structure and excellent physical and chemical properties. However, the photogenerated carriers of pure BiFeO3 are easy to recombine, and the active sites are relatively few, which restricts its development. At present, its piezoelectric photocatalytic performance can be enhanced by various modification methods. The piezoelectric effect is induced under the action of an external electric field, and various excellent catalyst materials are compounded to inhibit the recombination of internal electrons and holes, thereby enhancing the piezoelectric photocatalytic activity of the catalyst. However, the current improvement effect needs to be improved. Summary of the invention

[0005] The purpose of the present application is to provide a piezoelectric photocatalytic composite material slurry and a piezoelectric photocatalytic device, aiming to solve the technical problem of how to provide a piezoelectric photocatalytic device with better catalytic effect.

[0006] In order to achieve the above application purpose, the technical solution adopted in this application is as follows:

[0007] In a first aspect, the present application provides a piezoelectric photocatalytic composite material slurry, which, based on the total weight of the piezoelectric photocatalytic composite material slurry being 100%, is composed of the following components in percentage by weight:

[0008] Bismuth ferrite 10-20%;

[0009] Bismuth ferrite-based piezoelectric composite material 30-50%;

[0010] Dispersant 1-5%;

[0011] Binder 0.5-3%;

[0012] The remainder is solvent.

[0013] In a second aspect, the present application provides a piezoelectric photocatalytic device, which is prepared from the piezoelectric photocatalytic composite material slurry provided in the first aspect of the present application.

[0014] In the piezoelectric photocatalytic composite material slurry provided in the present application, bismuth ferrite and bismuth ferrite-based piezoelectric composite materials as base material components play an important role in the piezoelectric photocatalytic performance of the piezoelectric photocatalytic composite material slurry, and dispersants and binders as additives assist the slurry to be evenly dispersed, making the piezoelectric photocatalytic performance more stable. Among them, bismuth ferrite has good chemical stability and narrow bandgap photocatalytic properties. At the same time, bismuth ferrite is a ferroelectric material with a large spontaneous polarization and piezoelectric coefficient, which can convert mechanical energy into electrical energy through the piezoelectric effect; and bismuth ferrite-based piezoelectric composite materials as a piezoelectric photocatalytic composite material can better facilitate the separation of space photogenerated electrons and holes. After mixing with bismuth ferrite, the piezoelectric photocatalytic composite material slurry composed of the above-mentioned percentage dispersant and binder can construct a specific heterojunction, which can effectively improve the piezoelectric photocatalytic efficiency.

[0015] The piezoelectric photocatalytic device provided in the present application is prepared from a piezoelectric photocatalytic composite material slurry unique to the present application. Based on the specificity of the piezoelectric photocatalytic composite material slurry, the piezoelectric photocatalytic device of the present application has better piezoelectric photocatalytic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 1 is a SEM image of bismuth ferrite and bismuth ferrite-based piezoelectric composite material in the raw materials provided in Example 1 of the present application; wherein a is bismuth ferrite, and b is bismuth sulfide-bismuth ferrite composite material;

[0018] Figure 2 1 is a SEM image of bismuth ferrite and bismuth ferrite-based piezoelectric composite material in the raw materials provided in Example 2 of the present application; wherein a is bismuth ferrite, and c is molybdenum disulfide-bismuth ferrite composite material;

[0019] Figure 3 These are the SEM images of bismuth ferrite and bismuth ferrite-based piezoelectric composite materials in the raw materials provided in Example 3 of the present application; wherein a is bismuth ferrite, and d is molybdenum disulfide-bismuth sulfide-bismuth ferrite composite material. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0021] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0022] In the present application, "at least one" means one or more, "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items.

[0023] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and 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 the present application.

[0024] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0025] The weight of the relevant components mentioned in the embodiment description of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the embodiment description of the present application, it is within the scope disclosed in the embodiment description of the present application. Specifically, the mass described in the embodiment description of the present application can be a mass unit known in the chemical industry such as μg, mg, g, kg, etc.

[0026] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0027] As an emerging piezoelectric photocatalyst, bismuth ferrite plays an important role in the field of piezoelectric photocatalysis due to its special structure and excellent physical and chemical properties. However, the photogenerated carriers of pure phase BiFeO3 are easy to recombine and have relatively few active sites.

[0028] In the existing reports, the research on bismuth ferrite catalysts is focused on the preparation of powders, powder modification to increase activity and surface area, or the preparation of thin films. There are few research reports on bismuth ferrite materials in the field of piezoelectric photocatalysis and the preparation and structural design of three-dimensional catalyst devices. Bulk structure catalysts can increase the specific surface area and increase the effective interaction area with reactants through internal structure design. Compared with powder catalysts, they are easier to be recycled and reused, which is green and environmentally friendly. At the same time, their piezoelectric properties can be improved through structural design. However, the composition of its raw materials is crucial to the preparation of such bulk structure catalyst devices.

[0029] Therefore, the present application develops a piezoelectric photocatalytic composite material slurry, which can be used to prepare semiconductor piezoelectric photocatalytic devices with better catalytic effects, especially by 3D printing technology. The specific technical solution is as follows.

[0030] In a first aspect, the present invention provides a piezoelectric photocatalytic composite material slurry. Taking the total weight of the piezoelectric photocatalytic composite material slurry as 100%, the slurry is composed of the following components in percentage by weight:

[0031] Bismuth ferrite 10-20%;

[0032] Bismuth ferrite-based piezoelectric composite material 30-50%;

[0033] Dispersant 1-5%;

[0034] Binder 0.5-3%;

[0035] The remainder is solvent.

[0036] In the piezoelectric photocatalytic composite material slurry provided in the present application, bismuth ferrite and bismuth ferrite-based piezoelectric composite materials are used as base material components, while dispersants and binders are used as additives to assist the slurry in being evenly dispersed. A piezoelectric photocatalytic composite material slurry composed of a mixture of the above-mentioned percentages of bismuth ferrite, bismuth ferrite-based piezoelectric composite materials, dispersants and binders can construct a specific heterojunction, which effectively improves the piezoelectric photocatalytic efficiency under coordinated action.

[0037] In some embodiments, the bismuth ferrite content in the piezoelectric photocatalytic composite material slurry can be 10%, 12%, 14%, 18%, 20%, etc.; the bismuth ferrite-based piezoelectric composite material content can be 30%, 35%, 38%, 40%, 45%, 48%, 50%, etc. Bismuth ferrite is a photocatalyst with excellent chemical stability and narrow band gap. At the same time, it is also a ferroelectric material with a large spontaneous polarization and piezoelectric coefficient. It can convert mechanical energy into electrical energy through the piezoelectric effect. These characteristics make bismuth ferrite a possible piezoelectric photocatalytic material. The piezoelectric effect of self-polarization is conducive to the separation of spatial photogenerated electrons and holes. The photocatalytic performance of bismuth ferrite is enhanced under light excitation and ultrasonic conditions. Therefore, a bismuth ferrite-based piezoelectric composite material with a better light response range and more active sites is constructed with bismuth ferrite to form a specific heterojunction. Under the coordinated ultrasonic stimulation of light, the light absorption range of bismuth ferrite can be effectively widened, the internal carrier migration path can be regulated, the carrier recombination can be suppressed, the reaction active sites can be increased, and more active free radicals for catalytic reactions can be generated, thereby enhancing the piezoelectric photocatalytic activity of the material. Bismuth ferrite powder and bismuth ferrite-based piezoelectric composite material powder are used as base material components, which have a decisive role in the piezoelectric photocatalytic performance of the piezoelectric photocatalytic composite material slurry of the embodiment of the present invention. The bismuth ferrite-based piezoelectric composite material in this embodiment can be obtained by compounding different types of materials to construct a heterojunction, including a non-piezoelectric material-bismuth ferrite composite material, a piezoelectric material-bismuth ferrite dual piezoelectric composite material, and a piezoelectric material-non-piezoelectric material bismuth ferrite ternary composite material system.

[0038] In some embodiments, the morphology of the bismuth ferrite powder may include block, sheet, fiber, sphere, etc. The morphology of the bismuth ferrite-based composite piezoelectric material powder may include block, sheet, fiber, sphere, etc. For example, the bismuth ferrite powder and the bismuth ferrite-based composite piezoelectric material powder may be synthesized by hydrothermal method or electrostatic spinning method, respectively.

[0039] In some embodiments, the bismuth ferrite-based piezoelectric composite material includes at least one of a non-piezoelectric material-bismuth ferrite composite material, a piezoelectric material-bismuth ferrite bi-piezoelectric composite material, and a piezoelectric material-non-piezoelectric material-bismuth ferrite ternary composite material.

[0040] In some embodiments, the non-piezoelectric material-bismuth ferrite composite material includes a bismuth sulfide-bismuth ferrite composite material. In some embodiments, the piezoelectric material-bismuth ferrite bi-piezoelectric composite material includes a molybdenum disulfide-bismuth ferrite composite material. In some embodiments, the piezoelectric material-non-piezoelectric material-bismuth ferrite ternary composite material includes a molybdenum disulfide-bismuth sulfide-bismuth ferrite composite material.

[0041] In some embodiments, the molybdenum disulfide-bismuth ferrite composite material includes bismuth ferrite nanofibers and bismuth sulfide nanoparticles bound to the surface of the bismuth ferrite nanofibers. Specifically, bismuth ferrite (BFO) nanofibers can be prepared by an electrostatic spinning method, and then the non-piezoelectric material bismuth sulfide (Bi2S3) is compounded by a hydrothermal method to construct a bismuth sulfide-bismuth ferrite composite material: that is, Bi2S3 / BFO composite material. The molybdenum disulfide-bismuth ferrite composite material includes bismuth ferrite nanofibers and molybdenum disulfide nanosheets bound to the surface of the bismuth ferrite nanofibers. Specifically, bismuth ferrite nanofibers can be prepared by an electrostatic spinning method, and then the piezoelectric material molybdenum disulfide (MoS2) is compounded by a hydrothermal method to construct a molybdenum disulfide-bismuth ferrite composite material: that is, MoS2 / BFO composite material.

[0042] In some embodiments, the bismuth ferrite-based piezoelectric composite material includes a molybdenum disulfide-bismuth sulfide-bismuth ferrite composite material, and the molybdenum disulfide-bismuth sulfide-bismuth ferrite composite material includes bismuth ferrite nanofibers and bismuth sulfide nanoparticles and molybdenum disulfide nanosheets bound to the surface of the bismuth ferrite nanofibers. Specifically, the bismuth ferrite nanofibers can be prepared by electrospinning, and then the molybdenum disulfide (MoS2) nanosheet solid powder material can be synthesized by a hydrothermal method, and finally, molybdenum disulfide and bismuth sulfide are compounded on the bismuth ferrite nanofibers by a one-step solvothermal method to construct a molybdenum disulfide-bismuth sulfide-bismuth ferrite composite material: that is, MoS2 / Bi2S3 / BFO ternary heterogeneous composite material. The catalytic activity of the ternary heterojunction piezoelectric composite material MoS2 / Bi2S3 / BFO prepared by loading MoS2 nanosheets onto BFO nanofibers by means of Bi-S bonds can be enhanced, and the photocatalytic performance of the ternary heterojunction can be enhanced under ultrasonic conditions. Therefore, the photocatalytic activity of the MoS2 / Bi2S3 / BFO ternary piezoelectric photocatalytic composite material is significantly improved.

[0043] The above-mentioned steps of preparing bismuth ferrite nanofibers by electrospinning include: dissolving Bi(NO3)3·H2O and Fe(NO3)3·9H2O in N,N-dimethylformamide (DMF) solution, and then adding ethanol and glacial acetic acid in sequence. Then, polyvinyl pyrrolidone (PVP) is added, and the mixture is stirred evenly until it becomes brown-yellow and translucent. Then, the solution is completely absorbed with a syringe, an antistatic plastic tube is installed and installed on the electrospinning device, and the corresponding bismuth ferrite nanofibers are prepared by setting the fiber parameters of electrospinning.

[0044] Specifically, in the molybdenum disulfide-bismuth sulfide-bismuth ferrite composite material: the mass ratio of bismuth ferrite nanofibers, bismuth sulfide nanoparticles and molybdenum disulfide nanosheets is (4-5): (2-3): (2-3); specifically, it can be 5:3:2. Further, the diameter of the bismuth ferrite nanofibers is 50-200nm, the diameter of the bismuth sulfide nanoparticles is 10-20nm, and the thickness of the molybdenum disulfide nanosheets is 10-20nm. Controlling the morphology and shape of the molybdenum disulfide-bismuth sulfide-bismuth ferrite composite material powder within the above range can make the particles easily dispersed in the solvent system to form a uniform piezoelectric photocatalytic composite material slurry with good rheological properties.

[0045] In some embodiments, the dispersant content in the piezoelectric photocatalytic composite material slurry can be 1%, 3%, 5%, etc. The dispersant can specifically include at least one of carboxymethyl cellulose, polyacrylic acid, sodium ethylenediaminetetraacetate, sodium silicate, sodium phosphate, and sodium carbonate. The binder content in the piezoelectric photocatalytic composite material slurry can be 0.5%, 1%, 1.5%, 2%, 3%, etc. The dispersant can specifically include at least one of ethyl silicate, epoxy resin, and polyvinyl butyral. The above-mentioned dispersant can improve the dispersibility of each component contained in the piezoelectric photocatalytic composite material slurry, thereby improving the stability of the piezoelectric photocatalytic composite material slurry system, and at the same time act with the binder component to improve and improve the comprehensive rheological properties and uniform stability of the slurry.

[0046] In some embodiments, the solvent includes at least one of water, ethanol, and acetone. For example, the solvent may be deionized water. The cost of using deionized water is lower than that of other solvent systems. At the same time, the bismuth ferrite, bismuth ferrite-based piezoelectric composite material, dispersant, and binder are dissolved in a water solvent to obtain a stable water-based piezoelectric photocatalytic composite material slurry.

[0047] In a second aspect, the present invention provides a piezoelectric photocatalytic device. The piezoelectric photocatalytic device of the present invention is prepared from the piezoelectric photocatalytic composite material slurry provided in the first aspect of the present invention.

[0048] For example, the piezoelectric photocatalytic device is a three-dimensional piezoelectric photocatalytic device prepared by a 3D printing process from a piezoelectric photocatalytic composite material slurry. The shape of the printed piezoelectric photocatalytic device includes at least one of a wood pile structure, a cylinder, a horseshoe, and a cube.

[0049] 3D printing technology is based on direct writing of fluid slurry. The basic process is to squeeze the slurry from the needle of the container, and drive the needle along the designed path through a computer-controlled three-dimensional platform to finally obtain a device with a three-dimensional periodic complex spatial structure. Excellent device performance can be obtained by precisely controlling the shape and size of the product, the connection between layers, and the composition of the micro-region.

[0050] In some embodiments, the slurry used to prepare a three-dimensional piezoelectric photocatalytic device by a 3D printing process includes: bismuth ferrite, bismuth ferrite-based piezoelectric composite material, a dispersant, a solvent and a binder; based on the slurry weight as 100%, bismuth ferrite is 10-20wt%, and bismuth ferrite-based piezoelectric composite material is 30-50wt%; that is, the solid phase content is 40-70%wt, the dispersant content is 1-5%wt, and the binder content is 0.5-3%wt.

[0051] In some embodiments, the method for preparing a piezoelectric photocatalytic device in an embodiment of the present application includes steps such as 3D printing blank forming, drying, and subsequent heat treatment. The bismuth ferrite and bismuth ferrite-based composite piezoelectric material powders used in the slurry can be prepared by hydrothermal method, electrospinning and other methods, and the morphology includes block, sheet, fiber, sphere, etc. Among them, the bismuth ferrite-based piezoelectric composite material powder includes various systems such as non-piezoelectric material-bismuth ferrite composite material, piezoelectric material-bismuth ferrite dual piezoelectric composite material and piezoelectric material-non-piezoelectric material-bismuth ferrite ternary composite material.

[0052] In some embodiments, a method for preparing a three-dimensional piezoelectric photocatalytic device comprises the following steps:

[0053] Different three-dimensional piezoelectric photocatalytic device structures are designed, such as wood pile structure, cylinder, horseshoe, cube, etc., and converted into code language such as gcode. The three-dimensional motion platform is formed along the path formed by the above code language, and the above piezoelectric photocatalytic composite material slurry is prepared layer by layer by direct writing 3D printing technology, and finally a photocatalytic device blank with different three-dimensional structures is obtained, and subsequent drying and heat treatment processes are carried out.

[0054] The embodiment of the present application uses a three-dimensional photocatalytic device for direct writing 3D printing. The bismuth ferrite-based piezoelectric photocatalytic composite material with different morphologies and bismuth ferrite are used as the base material, and a dispersant and a binder are used as auxiliary agents. The content of each component is precisely controlled, so that the piezoelectric photocatalytic composite material slurry used for direct writing 3D printing in this embodiment has adjustable viscoelastic response and shear thinning rheological characteristics, and can be smoothly extruded to obtain a piezoelectric photocatalytic device with a three-dimensional structure.

[0055] Specifically, the printing rate of the piezoelectric composite material slurry is 100-500 mm / min, and the pressure of the piezoelectric composite material slurry extruded in the needle is 0.1-0.5 MPa. The shape of the printed three-dimensional piezoelectric photocatalytic device structure can be any one of a wood pile structure, a cylinder, a horseshoe, and a cube, and the length, width, and height can be set as needed, for example, 5-20 mm in length, 5-20 mm in height, and 5-20 mm in width.

[0056] Specifically, the drying process includes drying the three-dimensional green body under vacuum conditions at 60°C for 8-12 hours. The heat treatment process includes pre-sintering the dried green body at 100-400°C for 1-4 hours, and then sintering it at a high temperature of 800-1200°C at a heating rate of 2-5°C / min for 2h-4h. The degradation ability of the three-dimensional piezoelectric photocatalytic device on ciprofloxacin under the action of piezoelectricity and light is further studied in the future.

[0057] The piezoelectric photocatalytic device provided in the embodiment of the present application is formed by printing the piezoelectric photocatalytic composite material slurry of the embodiment of the present application using direct writing 3D printing technology. The piezoelectric photocatalytic device is prepared based on 3D printing technology, and the structure can be designed in a diversified manner. At the same time, the shape and size of the catalytic device can be designed according to the application requirements of pollutant degradation. Under the synergistic effect of light and piezoelectricity, it reflects the efficient degradation performance of pollutants such as ciprofloxacin, providing an efficient and feasible solution for wastewater treatment and organic pollutant degradation.

[0058] The following describes the invention in conjunction with specific embodiments.

[0059] Example 1

[0060] A piezoelectric photocatalytic composite material slurry for direct molding 3D printing. Taking the weight of the piezoelectric photocatalytic composite material slurry as 100%, it comprises:

[0061] (1) Bismuth ferrite powder, such as Figure 1 As shown in a, the SEM morphology is blocky, the particle size is about 200nm, and the content is 20wt%;

[0062] (2) Non-piezoelectric material-bismuth ferrite composite material: bismuth sulfide-bismuth ferrite composite material (Bi2S3 / BFO), SEM morphology as shown Figure 1 As shown in b, the content is 50wt%;

[0063] Preparation method: Dissolve 1 mmol of thiourea in 20 mL of deionized water to prepare a thiourea solution. Add 0.1 g of BiFeO3 nanofibers to 30 mL of deionized water and disperse them ultrasonically for 30 minutes. Add 2 mL of the above thiourea solution dropwise during stirring and continue to disperse in ultrasound for 30 minutes. Then, transfer the resulting mixture to a hydrothermal reactor and continue heating at 180°C for 12 hours. After the hydrothermal reaction is completed, repeatedly centrifuge and wash the product with a mixture of ethanol and water, and finally dry the product in a drying oven at 60°C for 12 hours to obtain Bi2S3 / BFO.

[0064] (3) Dispersant: carboxymethyl cellulose, content: 3 wt%;

[0065] (4) Binder: ethyl silicate, content: 1 wt%;

[0066] (5) Solvent: deionized water, content: 26 wt %.

[0067] Example 2

[0068] A piezoelectric photocatalytic composite material slurry for direct molding 3D printing. Taking the weight of the piezoelectric photocatalytic composite material slurry as 100%, it comprises:

[0069] (1) Bismuth ferrite powder, such as Figure 2 As shown in a, the SEM morphology is blocky, the particle size is about 200nm, and the content is 20wt%;

[0070] (2) Piezoelectric material-bismuth ferrite composite material: Molybdenum disulfide-bismuth ferrite composite material (MoS2 / BFO), SEM morphology as shown Figure 2 As shown in c, the content is 50wt%;

[0071] Preparation method: Add 0.35g Na2MoO4 and 0.76g thiourea to a beaker containing 40mL deionized water and stir ultrasonically for 30min at room temperature to obtain a molybdenum disulfide precursor solution. Add 0.1g BiFeO3 nanofibers to 30mL deionized water and disperse ultrasonically for 30min. During the stirring process, add 2mL of the above molybdenum disulfide precursor solution dropwise and continue to disperse in ultrasound for 30min. Then, transfer the obtained mixture to a hydrothermal reactor and continue heating at 180°C for 12h. After the hydrothermal reaction is completed, the product is repeatedly centrifuged and washed with a mixture of ethanol and water, and finally the product is dried in a drying oven at 60°C for 12h to obtain MoS2 / BFO.

[0072] (3) Dispersant: carboxymethyl cellulose, content: 3 wt%;

[0073] (4) Binder: ethyl silicate, content: 1 wt%;

[0074] (5) Solvent: deionized water, content: 26 wt %.

[0075] Example 3

[0076] A piezoelectric photocatalytic composite material slurry for direct molding 3D printing. Taking the weight of the piezoelectric photocatalytic composite material slurry as 100%, it comprises:

[0077] (1) Bismuth ferrite powder, such as Figure 3 As shown in a, the SEM morphology is blocky, the particle size is about 200nm, and the content is 20wt%;

[0078] (2) Piezoelectric material-non-piezoelectric material-bismuth ferrite composite material: Molybdenum disulfide-bismuth sulfide-bismuth ferrite composite material (MoS2 / Bi2S3 / BFO), SEM morphology as shown Figure 3 As shown in d, the content is 50wt%;

[0079] 0.35g Na2MoO4 and 0.76g thiourea were added to a beaker containing 40mL deionized water and ultrasonically stirred at room temperature for 30min. Subsequently, the black suspension was transferred to a 100mL autoclave, the reaction temperature was set to 180°C, and the insulation time was 18h. After the reaction was completed, a high-speed centrifuge was used to centrifuge the solid and liquid, and the sample was washed alternately with anhydrous ethanol and deionized water several times. The sample was dried in an oven at 60°C for 10h to obtain a MoS2 solid powder material.

[0080] Dissolve 0.55g of ammonium tetrathiomolybdate in 30mL of DMF and stir for 30min to obtain an ammonium tetrathiomolybdate solution. Then weigh 0.2g of BiFeO3 nanofibers and add them to the above ammonium tetrathiomolybdate solution, and ultrasonicate for 40min to make ammonium tetrathiomolybdate fully contact with BFO nanofibers. Then transfer the mixed solution to a high-pressure reactor containing the above 1g MoS2 solid powder material, stir, and react at 180°C for 18h. Finally, use DMF and ethanol to wash the sample obtained after centrifugation several times. Finally, dry the sample in an oven at 60°C for 24h to obtain MoS2 / Bi2S3 / BiFeO3.

[0081] (3) Dispersant: carboxymethyl cellulose, content: 3 wt%;

[0082] (4) Binder: ethyl silicate, content: 1 wt%;

[0083] (5) Solvent: deionized water, content: 26 wt %.

[0084] Performance Testing

[0085] The piezoelectric photocatalytic composite material slurry of the above-mentioned Examples 1-3 is printed using direct writing 3D printing technology to form a three-dimensional piezoelectric photocatalytic device, and the method is as follows:

[0086] S1: Design a three-dimensional piezoelectric photocatalytic device structure of a wood pile structure, convert it into a code language such as gcode, and form a three-dimensional motion platform along the path formed by the above code language. Inject the piezoelectric photocatalytic composite material slurry provided in the above embodiments 1-3 into a syringe with a needle diameter of 0.2 mm.

[0087] S2: Setting the printing equipment parameters: the printing rate is 400 mm / min, and the pressure at which the piezoelectric photocatalytic composite material slurry is extruded in the needle is 0.3 MPa.

[0088] S3: Print the piezoelectric photocatalytic composite material slurry into a three-dimensional embryo (wood pile structure, length 10 mm, height 10 mm, width 10 mm).

[0089] S4: The three-dimensional green body is placed under vacuum at 60°C and dried for 12 hours. The dried green body is pre-sintered at 200°C for 4 hours, and then sintered at 950°C for 2 hours at a heating rate of 3°C / min to obtain a final three-dimensional piezoelectric photocatalytic device.

[0090] Under the synergistic effect of illumination and piezoelectricity, the piezoelectric photocatalytic degradation efficiency of the three-dimensional piezoelectric photocatalytic device prepared by the piezoelectric photocatalytic composite material slurry of Example 1 for ciprofloxacin within 100 minutes was 79%, the piezoelectric photocatalytic degradation efficiency of the three-dimensional piezoelectric photocatalytic device prepared by the piezoelectric photocatalytic composite material slurry of Example 2 for ciprofloxacin within 100 minutes was 87%, and the piezoelectric photocatalytic degradation efficiency of the three-dimensional piezoelectric photocatalytic device prepared by the piezoelectric photocatalytic composite material slurry of Example 3 for ciprofloxacin within 100 minutes reached 91%.

[0091] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A piezoelectric photocatalytic composite material slurry, characterized in that: Taking the total weight of the piezoelectric photocatalytic composite material slurry as 100%, the following components are included in weight percentage: composition: Bismuth ferrite 10-20%; Bismuth ferrite-based piezoelectric composite material 30-50%; Dispersant 1-5%; Binder 0.5-3%; The remainder is solvent.

2. The piezoelectric photocatalytic composite material slurry according to claim 1, characterized in that: The bismuth ferrite-based piezoelectric composite material comprises at least one of a non-piezoelectric material-bismuth ferrite composite material, a piezoelectric material-bismuth ferrite bi-piezoelectric composite material, and a piezoelectric material-non-piezoelectric material-bismuth ferrite ternary composite material.

3. The piezoelectric photocatalytic composite material slurry according to claim 2, characterized in that: The non-piezoelectric material-bismuth ferrite composite material includes a bismuth sulfide-bismuth ferrite composite material; And / or, the piezoelectric material-bismuth ferrite bi-piezoelectric composite material includes a molybdenum disulfide-bismuth ferrite composite material; And / or, the piezoelectric material-non-piezoelectric material-bismuth ferrite ternary composite material includes a molybdenum disulfide-bismuth sulfide-bismuth ferrite composite material.

4. The piezoelectric photocatalytic composite material slurry according to claim 3, characterized in that: The bismuth ferrite-based piezoelectric composite material includes a molybdenum disulfide-bismuth sulfide-bismuth ferrite composite material, and the molybdenum disulfide-bismuth sulfide-bismuth ferrite composite material includes bismuth ferrite nanofibers and bismuth sulfide nanoparticles and molybdenum disulfide nanosheets combined on the surface of the bismuth ferrite nanofibers.

5. The piezoelectric photocatalytic composite material slurry according to claim 4, characterized in that: The mass ratio of the bismuth ferrite nanofibers, the bismuth sulfide nanoparticles and the molybdenum disulfide nanosheets is (4-5):(2-3):(2-3).

6. The piezoelectric photocatalytic composite material slurry according to claim 4, characterized in that: The diameter of the bismuth ferrite nanofiber is 50-200 nm, the diameter of the bismuth sulfide nanoparticle is 10-20 nm, and the thickness of the molybdenum disulfide nanosheet is 10-20 nm.

7. The piezoelectric photocatalytic composite material slurry according to any one of claims 1 to 6, characterized in that: The dispersant includes at least one of carboxymethyl cellulose, polyacrylic acid, sodium ethylenediaminetetraacetate, sodium silicate, sodium phosphate, and sodium carbonate; And / or, the binder includes at least one of ethyl silicate, epoxy resin, and polyvinyl butyral.

8. The piezoelectric photocatalytic composite material slurry according to any one of claims 1 to 6, characterized in that: The solvent includes at least one of water, ethanol and acetone.

9. A piezoelectric photocatalytic device, characterized in that: The piezoelectric photocatalytic device is prepared from the piezoelectric photocatalytic composite material slurry described in any one of claims 1-8.

10. The piezoelectric photocatalytic device according to claim 9, characterized in that: The piezoelectric photocatalytic device is a three-dimensional piezoelectric photocatalytic device prepared by a 3D printing process using the bismuth ferrite-based composite piezoelectric material slurry; and / or, The shape of the piezoelectric photocatalytic device includes at least one of a wood pile structure, a cylinder, a horseshoe, and a cube.

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