A bismuth titanate tantalate nanosheet piezoelectric catalyst, a preparation method and application thereof

Abstract

The application discloses a Bi4Ti3O12 nanosheet piezoelectric catalyst and a preparation method and application thereof. Bi(NO3)3*5H2O, Ti(OC4H9)4 and Ta2O5 are used as raw materials to prepare a precursor through co-precipitation, NaCl and KCl are used as molten salts to mix the precursor, and then ball milling is carried out, the obtained powder after the ball milling is dried, and then a molten salt reaction is carried out, so that the product is obtained, and after washing and drying, the Bi4Ti3O12 nanosheet piezoelectric catalyst is obtained, and is successfully applied to piezoelectric catalytic degradation of rhodamine B. The prepared Bi4Ti3O12 nanosheet piezoelectric catalyst is a nanosheet with high purity and good crystallinity, and a high-activity exposed surface is beneficial to improving the transmission and separation of photo-generated charges, improving the piezoelectric catalytic performance of the Bi4Ti3O12 nanosheet piezoelectric catalyst, and the preparation process is simple.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of catalytic materials, and particularly relates to a titanium-tantalum-bismuth nanosheet piezoelectric catalyst and a preparation method and application thereof. BACKGROUND

[0002] In recent years, with the accelerated development of industry, the amount of industrial wastewater discharged has increased year by year, and water pollution sources are widespread. These wastewaters also have a serious impact on human health, and the environmental pollution problem caused by dyeing industrial wastewater is particularly serious. For example, rhodamine B dye has stable molecular structure, is difficult to decompose, has complex composition and high heavy metal content. These characteristics make it difficult to treat dye wastewater. The current mainstream treatment methods such as adsorption and precipitation cannot completely solve this problem. Therefore, there is an urgent need for a low-cost, low-energy and efficient method to treat wastewater. In this context, catalytic technology is considered an effective wastewater treatment technology. At present, catalysis has made great progress in degrading pollutants. Common catalytic methods include photocatalysis, electrocatalysis and biodegradation. However, photocatalysis has the disadvantages of low conversion efficiency and small light response range, electrocatalysis has the problem of high energy consumption, and biodegradation has the defects of incomplete degradation and high cost. Therefore, piezoelectric catalysis as a new type of catalytic method is proposed. This technology uses small mechanical vibrations to generate electric charges on the surface of piezoelectric materials, and then generates ·OH and ·O2 - active free radicals to degrade pollutants. It effectively utilizes the ubiquitous mechanical energy in the environment such as noise and vibration, reduces energy consumption, and is suitable for all-weather use. It is considered a promising technology to solve environmental pollution problems.

[0003] So far, scientists have found many piezoelectric catalytic materials, such as perovskite oxides, wurtzite structure ZnO, 2D ultrathin piezoelectric catalytic materials such as easily exfoliated transition metal sulfides / selenides, and bismuth layer compounds. Among them, bismuth layer compounds have attracted widespread attention due to their structural characteristics and high Curie temperature. This type of compound is composed of perovskite-like layers (A n-1 BnO 3n+1 ) 2- and bismuth oxide layers (Bi2O2) 2+ arranged in a certain pattern. Bismuth layer piezoelectric ceramics have low dielectric constant, high Curie temperature, obvious anisotropy of electromechanical coupling coefficient, low aging rate, high resistivity, large dielectric breakdown strength, low sintering temperature and other characteristics. Based on the good piezoelectric properties of bismuth layer compounds, their application in piezoelectric catalysis has been reported in recent years, such as Bi4Ti3O 12It has excellent piezoelectric catalytic hydrogen peroxide generation performance. Bi3TiTaO9 is a bismuth layer compound, which is widely studied in the field of piezoelectric materials, but there is no relevant report in the field of catalysis. At present, the preparation method of Bi3TiTaO9 is mostly solid phase sintering method, and the prepared sample is often not suitable for use in the field of catalysis; hydrothermal and sol-gel methods are widely used in the preparation of catalysts, but the yield of these two methods is extremely low, which is not suitable for large-scale industrial application.

[0004] In view of the technical problem that the sample prepared by the preparation process of Bi3TiTaO9 in the prior art has too many impurities and is often not suitable for use in the field of catalysis, a new preparation process of Bi3TiTaO9 needs to be explored to improve the purity of Bi3TiTaO9, so that Bi3TiTaO9 has higher piezoelectric response and can meet the requirements of large-scale industrial production. SUMMARY

[0005] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a titanium tantalum bismuth nanosheet piezoelectric catalyst and a preparation method and application thereof, so as to solve the technical problem of too many impurities in the sample prepared by one-step molten salt method.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] The application discloses a preparation method of a titanium tantalum bismuth nanosheet piezoelectric catalyst, comprising:

[0008] First, Bi(NO3)3.5H2O, Ti(OC4H9)4 and Ta2O5 are prepared into a precursor by a coprecipitation method, then NaCl and KCl are mixed with the precursor and ball milled, dried, and after molten salt reaction, washed, dried, and finally a titanium tantalum bismuth nanosheet piezoelectric catalyst is obtained.

[0009] Preferably, the molar ratio of NaCl:KCl:precursor is (48-52):(48-52):1.

[0010] Preferably, the ball milling time is 4-6h; the drying temperature is 60-80℃; and the drying time is 10-12h.

[0011] Preferably, in the heating process of the molten salt reaction, the temperature is raised to 750-850℃ at a heating rate of 3-5℃ / min, and the reaction is carried out for 1-4h.

[0012] Preferably, in the cooling process of the molten salt reaction, the temperature is lowered to 400-500℃ at a cooling rate of 3-5℃ / min, and then the furnace is cooled to room temperature.

[0013] Preferably, the preparation method of the precursor comprises: adding Ti(OC4H9)4 ethanol solution and Ta2O5 aqueous solution into Bi(NO3)3 nitric acid solution in sequence, stirring for 0.5-1 h, adjusting the pH value to 9-10, continuing to stir for 1.5-2 h until the powder is completely precipitated, washing with deionized water until neutral, drying at 60-80 DEG C for 10-12 h, to obtain the precursor; the Ti(OC4H9)4 ethanol solution is prepared by dissolving Ti(OC4H9)4 in anhydrous ethanol; the Ta2O5 aqueous solution is prepared by dissolving Ta2O5 in deionized water; and the Bi(NO3)3 nitric acid solution is prepared by dissolving Bi(NO3)3.5H2O in 3.9-4.1 mol / L HNO3.

[0014] Preferably, the molar ratio of Bi(NO3)3.5H2O:Ti(OC4H9)4:Ta2O5 is 6:2:1.

[0015] Preferably, the volume ratio of HNO3:anhydrous ethanol:deionized water is (3.9-4.1):(1.9-2.1):(4.9-5.1).

[0016] The application further discloses the bismuth titanate tantalate nanosheet piezoelectric catalyst prepared by the preparation method.

[0017] The application further discloses application of the bismuth titanate tantalate nanosheet piezoelectric catalyst in degradation of organic dyes.

[0018] Compared with the prior art, the application has the following beneficial effects:

[0019] The application discloses a preparation method of a bismuth titanate tantalate nanosheet piezoelectric catalyst.

[0020] The application further discloses the bismuth titanate tantalate nanosheet piezoelectric catalyst prepared by the preparation method, which has high purity and good crystallinity, has a nanosheet morphology, a width of 0.5-2 microns and a thickness of about 0.1 micron, has a high-activity exposed surface, is beneficial to improving the transport and separation of carriers, thereby improving the piezoelectric catalytic activity of the bismuth titanate tantalate nanosheet, and can improve the ability of the catalyst to respond to mechanical energy.

[0021] The application further discloses application of the bismuth titanate tantalate nanosheet piezoelectric catalyst in degradation of organic dyes. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The XRD pattern of the bismuth titanate tantalate nanosheet piezoelectric catalyst powder prepared for the embodiment 1 of the application;

[0023] Figure 2 SEM picture of the Bi2Ti2Ta2O11 nanosheet piezoelectric catalyst powder prepared for the embodiment 1 of the present application;

[0024] Figure 3 Curve of the degradation of rhodamine B by the Bi2Ti2Ta2O11 nanosheet piezoelectric catalyst powder prepared for the embodiment 1 of the present application under the action of ultrasonic. DETAILED DESCRIPTION

[0025] In order to make the personnel in the technical field better understand the present application scheme, the technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the present application.

[0026] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0027] The present application will be further described in detail below in combination with the drawings:

[0028] The present application discloses a preparation method of a Bi2Ti2Ta2O11 nanosheet piezoelectric catalyst, which uses Bi(NO3)3·5H2O, Ti(OC4H9)4 and Ta2O5 as raw materials to prepare a precursor by a co-precipitation method, mixes NaCl and KCl as a molten salt with the precursor and then performs ball milling, dries the obtained powder after ball milling, and obtains the Bi2Ti2Ta2O11 nanosheet piezoelectric catalyst through a molten salt reaction after washing and drying the obtained product.

[0029] A preparation method of a Bi2Ti2Ta2O11 nanosheet piezoelectric catalyst, specifically comprising:

[0030] Powders of Bi(NO3)3·5H2O, Ti(OC4H9)4, and Ta2O5 were added to HNO3, anhydrous ethanol, and deionized water, respectively, and stirred. The Ti(OC4H9)4 ethanol solution and Ta2O5 aqueous solution were then added dropwise to the Bi(NO3)3 nitric acid solution, and the mixture was stirred. Concentrated ammonia was added dropwise to adjust the pH to 9–10, and the mixture was stirred until the precursors were completely precipitated. The precursors were then rewashed with deionized water until neutral and dried. NaCl, KCl, and the precursors were mixed and prepared. The mixture was then placed in a ball mill jar, and appropriate amounts of grinding stones and anhydrous ethanol were added. After ball milling, the powder was dried in an oven. The powder particles were then ground into small particles using a mortar and pestle and placed in a muffle furnace. During the reaction, the muffle furnace was heated to the highest temperature and kept at that temperature. After cooling, the powder was washed with deionized water under magnetic stirring, repeating this process three to four times. After washing, deionized water was added, and the powder was centrifuged several times. The supernatant in the centrifuge tube was then added dropwise to AgNO3 solution. If no white precipitate was found, it indicated that the molten salt in the powder had been cleaned. If a white precipitate was found, the water was changed and the powder was centrifuged again until no white precipitate was found. After drying, bismuth titanate nanosheet piezoelectric catalyst was obtained.

[0031] The molten salt reaction is carried out at a temperature of 750–850°C for 1–4 hours; preferably, the molten salt reaction is carried out at a temperature of 800°C for 2 hours.

[0032] During the heating process of the molten salt reaction, the heating rate is controlled at 3-5℃ / min. During the cooling process, the temperature is reduced to 400-500℃ at a rate of 3-5℃ / min and then cooled to room temperature along with the furnace. Preferably, the heating rate is controlled at 5℃ / min, and during the cooling process, the temperature is reduced to 500℃ at a rate of 5℃ / min and then cooled to room temperature along with the furnace.

[0033] The coprecipitation process involves sequentially adding Ti(OC4H9)4 ethanol solution and Ta2O5 aqueous solution to Bi(NO3)3 nitric acid solution, stirring for 0.5–1 h (preferably 0.5 h), adjusting the pH to 9–10, washing, and drying to obtain the precursor.

[0034] The specific preparation schemes for Ti(OC4H9)4 ethanol solution, Ta2O5 aqueous solution, and Bi(NO3)3 nitric acid solution are as follows: Bi(NO3)3·5H2O is added to HNO3 to obtain Bi(NO3)3 nitric acid solution; Ti(OC4H9)4 is added to anhydrous ethanol to obtain Ti(OC4H9)4 ethanol solution; and Ta2O5 is added to deionized water to obtain Ta2O5 aqueous solution. Each solution is stirred for 0.5 to 1 hour, preferably for 0.5 hours.

[0035] The molar ratio of Bi(NO3)3·5H2O:Ti(OC4H9)4:Ta2O5 is 6:2:1.

[0036] The concentration of HNO3 is 3.9-4.1 mol / L; preferably, the concentration of HNO3 is 4 mol / L.

[0037] The volume ratio of HNO3: anhydrous ethanol: deionized water is (3.9-4.1):(1.9-2.1):(4.9-5.1); preferably, the volume ratio of HNO3: anhydrous ethanol: deionized water is 4:2:5.

[0038] The pH value is adjusted to 9-10 by dropwise adding concentrated ammonia water, and stirring for 1.5-2 h until the raw materials are completely precipitated; preferably, the stirring time is 1.5 h.

[0039] The washing specifically refers to continuously replacing the deionized water and centrifuging until the supernatant is neutral.

[0040] The precursor is dried at 60-80℃ for 10-12 h after washing; preferably, the drying temperature is 60℃, and the time is 12 h.

[0041] The molar ratio of NaCl: KCl: precursor (the relative atomic mass is calculated according to Bi3TiTaO9) is (48-52):(48-52):1; preferably, the molar ratio of NaCl: KCl: precursor is 50:50:1.

[0042] The ball milling specifically refers to placing the precursor, NaCl and KCl into a ball mill tank, adding ball stones and anhydrous ethanol into the ball mill tank, and ball milling for 4-6 h; preferably, the ball milling time is 4 h.

[0043] The washing specifically refers to washing several times under the condition of magnetic stirring at 450-500 rpm using deionized water.

[0044] The product is dried at 60-80℃ for 10-12 h after washing; preferably, the drying temperature is 60℃, and the time is 12 h.

[0045] When the titanium tantalum bismuth nanosheet piezoelectric catalyst prepared by the above method is used to degrade organic dye rhodamine B, 50 mg of the titanium tantalum bismuth nanosheet piezoelectric catalyst is added to 50 mL of a rhodamine B solution (the concentration is 10 ppm), so that the concentration of the titanium tantalum bismuth nanosheet piezoelectric catalyst is 1 mg / mL, and stirring is performed in the dark for 1 h to achieve adsorption-desorption equilibrium. Then, the reactor is placed in an ultrasonic cleaner and covered with aluminum foil paper to ensure that the powder and the solution are placed in completely dark conditions. The piezoelectric catalytic reaction is carried out under ultrasonic frequency of 40 KHz, and the power of the ultrasonic wave is 50 W. The water temperature is controlled at 25℃ by using a cooling circulating water method during the reaction. Every 20 min, 3 mL of liquid is taken, filtered after centrifugation, and the concentration change of rhodamine B is characterized by using a ultraviolet-visible spectrophotometer.

[0046] Example 1

[0047] A preparation method of a bismuth titanate tantalate nanosheet piezoelectric catalyst, comprising:

[0048] powders with a molar ratio of Bi(NO3)3·5H2O:Ti(OC4H9)4:Ta2O5=6:2:1 are added into a solution with a volume ratio of HNO3:anhydrous ethanol:deionized water=4:2:5 and stirred for 0.5 h; the concentration of HNO3 is 4 mol / L; the Ti(OC4H9)4 ethanol solution and the Ta2O5 aqueous solution are sequentially added into the Bi(NO3)3 nitric acid solution, and then stirred for 0.5 h; concentrated ammonia water is added dropwise to adjust the pH value to 9, and stirred for 1.5 h until the precursor is completely precipitated; the precursor is washed to neutral with deionized water and dried at 60℃ for 12 h; ingredients are prepared according to a molar ratio of NaCl:KCl:precursor (the relative atomic mass is calculated according to Bi3TiTaO9)=50:50:1; the raw materials corresponding to the stoichiometric ratio are put into a ball mill tank, an appropriate amount of ball stones and 50 mL of anhydrous ethanol are added, and ball milling is performed for 4 h; after being taken out, the powder particles are ground into small particles with a mortar and then put into a muffle furnace; during the reaction, the muffle furnace is heated to a maximum temperature of 800℃ at a speed of 5℃ / min, and kept at 800℃ for 2 h; during the cooling process, the temperature is decreased at a speed of 5℃ / min, and when the temperature is decreased to 500℃, the furnace is cooled to room temperature; after the cooling process is completed, the powder is washed under the condition of magnetic stirring at 500 rpm with deionized water, and the washing process is repeated four times; after the washing process is completed, deionized water is added and centrifuged at a speed of 10,000 revolutions per minute for 5 min; after centrifuging several times, the supernatant in the centrifuge tube is added dropwise into an AgNO3 solution; if there is no white precipitate, it indicates that the fused salt in the powder has been completely washed; if there is white precipitate, the water is replaced and the centrifugation is continued until no white precipitate is generated; the powder is dried in a 60℃ oven for 12 h to obtain the bismuth titanate tantalate nanosheet piezoelectric catalyst.

[0049] It can be seen from the comparison with the control group without adding catalyst that, under the action of ultrasound, the bismuth titanate tantalate nanosheet piezoelectric catalyst has good piezoelectric degradation performance for rhodamine B, and the degradation rate reaches 62% within 80 min; this is because the bismuth titanate tantalate nanosheet piezoelectric catalyst is a piezoelectric material, which can generate a piezoelectric potential under the action of mechanical external force (ultrasound), thereby inducing the generation of electrons and holes on the surface of the catalyst; the electrons and holes can react with oxygen and water to generate active substances such as superoxide anion free radicals and hydroxyl free radicals. Through the action of the generated active substances, electrons and holes, rhodamine B can be degraded into small molecules, carbon dioxide and water.

[0050] Referring to Figure 1 The XRD pattern of the bismuth titanate tantalate nanosheet piezoelectric catalyst powder prepared in Example 1 of the present application; it can be seen from the figure that the XRD pattern of the prepared bismuth titanate tantalate nanosheet piezoelectric catalyst is consistent with the characteristic peaks of bismuth titanate tantalate, indicating that the prepared bismuth titanate tantalate is a pure phase.

[0051] Referring to Figure 2 The SEM picture of the Bi2Ti2Ta2O11 nanosheet piezoelectric catalyst powder prepared in Example 1 of the present application; it can be seen from the picture that the prepared Bi2Ti2Ta2O11 nanosheet piezoelectric catalyst has a nanosheet morphology, the width is 0.5-2 μm, and the thickness is about 0.1 μm; this morphology is not only beneficial to reducing the carrier transmission path, but also can improve the ability of the catalyst to respond to mechanical energy, thereby improving the catalytic efficiency.

[0052] Referring to Figure 3 The curve of the Bi2Ti2Ta2O11 nanosheet piezoelectric catalyst powder prepared in Example 1 of the present application degrading rhodamine B under the action of ultrasound; it can be seen from the picture that when the piezoelectric catalysis degrades rhodamine B with a concentration of 10 ppm, the degradation efficiency of rhodamine B with the addition of the Bi2Ti2Ta2O11 nanosheet piezoelectric catalyst is significantly higher than that of the control group without the addition of the Bi2Ti2Ta2O11 nanosheet piezoelectric catalyst; the group with the addition of the Bi2Ti2Ta2O11 nanosheet piezoelectric catalyst can degrade 62% in 80 min, while the group without the addition of the Bi2Ti2Ta2O11 nanosheet piezoelectric catalyst can only degrade 15%.

[0053] Example 2

[0054] A preparation method of a Bi2Ti2Ta2O11 nanosheet piezoelectric catalyst, comprising:

[0055] The powder with a molar ratio of Bi(NO3)3·5H2O:Ti(OC4H9)4:Ta2O5=6:2:1 is added into a solution with a volume ratio of HNO3:anhydrous ethanol:deionized water=3.9:1.9:4.9 and stirred for 1 h; the concentration of HNO3 is 3.9 mol / L; the Ti(OC4H9)4 ethanol solution and the Ta2O5 aqueous solution are added into the Bi(NO3)3 nitric acid solution in sequence, and stirred for 1 h; ammonia water is added dropwise to adjust the pH value to 10, and stirred for 2 h until the precursor is completely precipitated; the precursor is washed to neutral with deionized water and dried at 80℃ for 10 h; the ingredients are prepared according to the molar ratio of NaCl:KCl:precursor (the relative atomic mass is calculated according to Bi3TiTaO9)=48:48:1; the raw materials corresponding to the stoichiometric ratio are put into a ball mill tank, an appropriate amount of ball stones and 50 mL of anhydrous ethanol are added, and ball milling is performed for 6 h; after taking out, drying in an oven, and grinding the powder particles into small particles with a mortar, the particles are put into a muffle furnace; during the reaction, the muffle furnace is heated to a maximum temperature of 750℃ at a rate of 3℃ / min, and kept at 750℃ for 4 h; during cooling, the temperature is lowered at a rate of 3℃ / min, and when the temperature is lowered to 500℃, the furnace is cooled to room temperature; after the cooling is completed, the powder is washed with deionized water under the condition of magnetic stirring at 450 rpm, and the washing is repeated four times; after the washing is completed, deionized water is added and centrifuged at a speed of 10,000 revolutions per minute for 5 min; after centrifuging several times, the supernatant in the centrifuge tube is added dropwise into an AgNO3 solution; if there is no white precipitate, it indicates that the molten salt in the powder has been completely washed; if there is a white precipitate, the water is replaced and centrifuged until no white precipitate is produced; the powder is dried in an oven at 80℃ for 10 h to obtain a bismuth titanate tantalate nanosheet piezoelectric catalyst.

[0056] Example 3

[0057] A method for preparing a bismuth titanate tantalate nanosheet piezoelectric catalyst, comprising:

[0058] The powder with a molar ratio of Bi(NO3)3·5H2O:Ti(OC4H9)4:Ta2O5=6:2:1 is added into a solution with a volume ratio of HNO3:anhydrous ethanol:deionized water=4.1:2.1:5.1 and stirred for 0.5 h; the concentration of HNO3 is 4.1 mol / L; the Ti(OC4H9)4 ethanol solution and the Ta2O5 aqueous solution are added into the Bi(NO3)3 nitric acid solution in sequence, and stirred for 0.5 h; ammonia water is added dropwise to adjust the pH value to 9, and stirred for 1.5 h until the precursor is completely precipitated; the precursor is washed to neutral with deionized water and dried at 60℃ for 12 h; the ingredients are prepared according to the molar ratio of NaCl:KCl:precursor (the relative atomic mass is calculated according to Bi3TiTaO9)=50:50:1; the raw materials corresponding to the stoichiometric ratio are put into a ball mill tank, an appropriate amount of ball stones and 50 mL of anhydrous ethanol are added, and ball milling is performed for 4 h; after taking out, drying in an oven, and grinding the powder particles into small particles with a mortar, the particles are put into a muffle furnace; during the reaction, the muffle furnace is heated to a maximum temperature of 800℃ at a rate of 4℃ / min, and kept at 800℃ for 2 h; during cooling, the temperature is decreased at a rate of 4℃ / min, and when the temperature decreases to 500℃, the furnace is cooled to room temperature; after the cooling is completed, the powder is washed with deionized water under the condition of magnetic stirring at 500 rpm, and the washing is repeated four times; after the washing is completed, deionized water is added and centrifuged at a speed of 10,000 revolutions per minute for 5 min; after centrifuging several times, the supernatant in the centrifuge tube is added dropwise into an AgNO3 solution; if there is no white precipitate, it indicates that the molten salt in the powder has been completely washed; if there is a white precipitate, the water is replaced and centrifuged until no white precipitate is produced; the powder is dried in an oven at 60℃ for 12 h to obtain a bismuth titanate tantalate nanosheet piezoelectric catalyst.

[0059] Example 4

[0060] A method for preparing a bismuth titanate tantalate nanosheet piezoelectric catalyst, comprising:

[0061] The powder with a molar ratio of Bi(NO3)3·5H2O:Ti(OC4H9)4:Ta2O5=6:2:1 is added into a solution with a volume ratio of HNO3:anhydrous ethanol:deionized water=4:2:5 and stirred for 0.5 h; the concentration of HNO3 is 4 mol / L; the Ti(OC4H9)4 ethanol solution and the Ta2O5 aqueous solution are added into the Bi(NO3)3 nitric acid solution in sequence, and stirred for 0.5 h; the pH value is adjusted to 9.5 by adding concentrated ammonia water, and stirred for 1.5 h until the precursor is completely precipitated; the precursor is washed to neutral with deionized water and dried at 80℃ for 12 h; the ingredients are prepared according to a molar ratio of NaCl:KCl:precursor (the relative atomic mass is calculated according to Bi3TiTaO9)=52:52:1; the raw materials corresponding to the stoichiometric ratio are put into a ball mill tank, an appropriate amount of ball stones and 50 mL of anhydrous ethanol are added, and ball milling is performed for 4 h; after being taken out, the powder is dried in an oven, and the powder particles are ground into small particles with a mortar and then put into a muffle furnace; during the reaction, the muffle furnace is heated to a maximum temperature of 750℃ at a rate of 4℃ / min, and kept at 750℃ for 2 h; during the cooling process, the temperature is decreased at a rate of 4℃ / min, and when the temperature decreases to 450℃, the furnace is cooled to room temperature; after the cooling process is completed, the powder is washed with deionized water under the condition of magnetic stirring at 450 rpm, and the process is repeated four times; after the washing process is completed, deionized water is added and centrifuged at a speed of 10,000 revolutions per minute for 5 min; after centrifuging several times, the supernatant in the centrifuge tube is added into an AgNO3 solution; if there is no white precipitate, it indicates that the molten salt in the powder has been completely washed; if there is a white precipitate, the water is replaced and centrifuged until no white precipitate is generated; the powder is dried in an oven at 80℃ for 12 h, and a Bi3TiTaO9 nanosheet piezoelectric catalyst is obtained.

[0062] Example 5

[0063] A method for preparing a Bi3TiTaO9 nanosheet piezoelectric catalyst, comprising:

[0064] The powder with a molar ratio of Bi(NO3)3·5H2O:Ti(OC4H9)4:Ta2O5=6:2:1 is added into a solution with a volume ratio of HNO3:anhydrous ethanol:deionized water=4:2:5 and stirred for 1h; the concentration of HNO3 is 4mol / L; the Ti(OC4H9)4 ethanol solution and the Ta2O5 aqueous solution are added into the Bi(NO3)3 nitric acid solution in sequence, and stirred for 1h; the pH value is adjusted to 9 by adding concentrated ammonia water, and stirred for 2h until the precursor is completely precipitated; the precursor is washed to neutral with deionized water and dried at 70℃ for 11h; the ingredients are prepared according to a molar ratio of NaCl:KCl:precursor (the relative atomic mass is calculated according to Bi3TiTaO9)=50:50:1; the raw materials corresponding to the stoichiometric ratio are put into a ball mill tank, an appropriate amount of ball stone and 50mL of anhydrous ethanol are added, and ball milling is performed for 5h; after being taken out, the powder is dried in an oven, and the powder particles are ground into small particles with a mortar and then put into a muffle furnace; during the reaction, the muffle furnace is heated to a maximum temperature of 850℃ at a speed of 5℃ / min, and kept at 850℃ for 1h; during the cooling process, the temperature is decreased at a speed of 5℃ / min, and when the temperature is decreased to 400℃, the furnace is cooled to room temperature; after the cooling process is completed, the powder is washed with deionized water under the condition of magnetic stirring at a speed of 500rpm, and the washing process is repeated for three times; after the washing process is completed, deionized water is added and centrifuged at a speed of 10,000r / min for 5min; after centrifuging for several times, the supernatant in the centrifuge tube is added into an AgNO3 solution; if there is no white precipitate, it indicates that the molten salt in the powder has been completely washed; if there is white precipitate, the water is replaced and centrifuged until no white precipitate is generated; the powder is dried in an oven at 70℃ for 11h, and a bismuth titanate tantalate nanosheet piezoelectric catalyst is obtained.

[0065] The above is only used to illustrate the technical idea of the present application, and cannot be used to limit the protection scope of the present application; any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the present application.

Claims

1. A method for preparing a Bi2Ti2Ta2O11 nanoplatelet piezoelectric catalyst, characterized in that, The application relates to a preparation method of a bismuth titanatantalate nanosheet piezoelectric catalyst. The molar ratio of NaCl:KCl:the precursor is (48-52):(48-52):1; in the heating process of the molten salt reaction, the temperature is raised to 750-850 DEG C at a temperature raising speed of 3-5 DEG C / min, and the reaction is carried out for 1-4 h; in the cooling process of the molten salt reaction, the temperature is reduced to 400-500 DEG C at a temperature reducing speed of 3-5 DEG C / min, and then the furnace is cooled to room temperature; The preparation method of the precursor comprises the following steps: Ti(OC4H9)4 ethanol solution and Ta2O5 aqueous solution are sequentially added into Bi(NO3)3 nitric acid solution, stirring is carried out for 0.5-1 h, the pH value is adjusted to 9-10, and then stirring is continuously carried out for 1.5-2 h until the powder is completely precipitated, the powder is washed with deionized water until neutral, and then the powder is dried at 60-80 DEG C for 10-12 h to obtain the precursor; the Ti(OC4H9)4 ethanol solution is prepared by dissolving Ti(OC4H9)4 in anhydrous ethanol; the Ta2O5 aqueous solution is prepared by dissolving Ta2O5 in deionized water; and the Bi(NO3)3 nitric acid solution is prepared by dissolving Bi(NO3)3.5H2O in 3.9-4.1 mol / L HNO3. The molar ratio of Bi(NO3)3.5H2O:Ti(OC4H9)4:Ta2O5 is 6:2:

1. The ball milling time is 4-6 h; the drying temperature is 60-80 DEG C; and the drying time is 10-12 h.

2. The method for preparing the bismuth titanate nanosheet piezoelectric catalyst according to claim 1, characterized in that, The volume ratio of HNO3:anhydrous ethanol:deionized water is (3.9-4.1):(1.9-2.1):(4.9-5.1).

3. The method for preparing the bismuth titanate nanosheet piezoelectric catalyst according to claim 1, characterized in that, 4. The bismuth titanatantalate nanosheet piezoelectric catalyst prepared by the preparation method in any one of claims 1-3.

5. The application of the bismuth titanatantalate nanosheet piezoelectric catalyst in claim 4 in degradation of organic dyes. ​

Images