Piezoelectric heterojunction catalyst for producing hydrogen peroxide as well as preparation method and application of piezoelectric heterojunction catalyst

Abstract

The invention discloses a piezoelectric heterojunction catalyst for producing hydrogen peroxide as well as a preparation method and application thereof, and belongs to the technical field of piezoelectric catalysis. The method comprises the following steps: mixing NH4VO3 and Na2MoO4. 2H2O, and dissolving the mixture in a NaOH solution to prepare a mixed solution A; bi (NO3) 3.5 H2O is dissolved in diluted HNO3, and a mixed solution B is prepared; mixing the mixed solution A with the mixed solution B to obtain a suspension; adding sodium dodecyl benzene sulfonate into the suspension liquid, adjusting the pH value of the suspension liquid to 6.5-7.5, then stirring, finally carrying out hydrothermal reaction, washing the obtained product, and drying to obtain the BiVO4 / Bi2MoO6 heterojunction piezoelectric catalyst. The heterojunction catalyst is in an ultrathin and dispersed nanosheet shape, and can generate stronger piezoelectric response; meanwhile, more active sites can be exposed through the nanosheet morphology, piezoelectric catalytic reaction is facilitated, and the technical problems that a heterojunction catalyst prepared through an existing preparation technology is weak in piezoelectric response and active sites, and high-yield hydrogen peroxide is difficult to produce are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of piezoelectric catalysis, and in particular relates to a piezoelectric heterojunction catalyst for producing hydrogen peroxide, a preparation method and an application thereof. Background Art

[0002] Hydrogen peroxide (H2O2) is widely used in disinfection, wastewater treatment, pharmaceutical synthesis, bleaching and other fields. It is an eco-friendly oxidant with broad application prospects. However, the current common industrial method for H2O2 production relies on the environmentally harmful and energy-intensive anthraquinone technology. As the mainstream process for industrial production of H2O2, the anthraquinone method has high energy consumption, high cost, high risk factor, and large emission of toxic byproducts. Therefore, it is urgent to explore environmentally friendly, efficient and convenient H2O2 synthesis technology. Piezocatalysis, as an emerging technology, can harvest mechanical energy widely present in nature (e.g., fluid kinetic energy, tidal energy, etc.) to drive reduction / oxidation reactions, providing a promising path for the green synthesis of H2O2.

[0003] The energy band arrangement and interface micro-contact of the semiconductor components in the heterojunction are crucial to achieve the superior piezoelectric catalytic activity. Among many possible energy band arrangements, heterojunctions with staggered conduction band (CB) and valence band (VB) positions are of significant importance due to effective charge carrier migration. Chinese Patent Publication No. CN115069236A discloses a bismuth molybdate heterojunction catalyst and its preparation method and application. Although the preparation method of the catalytic material is simple, the prepared photocatalytic material has high purity, low surface charge transfer resistance, high photocurrent density, stable intensity, high light absorption intensity, and excellent catalytic performance, the raw materials used in the preparation method cannot change the morphology of the heterojunction catalyst nanosheets, so the morphology of the prepared bismuth molybdate heterojunction catalyst nanosheets is stacked, and the agglomeration is relatively serious, resulting in weak piezoelectric response and active sites, which is not conducive to piezoelectric catalytic reaction and difficult to produce high yield of hydrogen peroxide. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a piezoelectric heterojunction catalyst for producing hydrogen peroxide and a preparation method and application thereof, so as to solve the technical problem that the heterojunction catalyst obtained by the existing preparation process has weak piezoelectric response and active sites, and is difficult to produce high-yield hydrogen peroxide.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for preparing a piezoelectric heterojunction catalyst, comprising the following steps: NH4VO3 and Na2MoO4·2H2O were mixed and dissolved in NaOH solution to prepare mixed solution A; Dissolve Bi(NO3)3·5H2O in dilute HNO3 solution to prepare mixed solution B; Mixing the mixed solution A with the mixed solution B by slowly adding dropwise under vigorous stirring to obtain a suspension; Adding surfactant sodium dodecylbenzene sulfonate to the suspension, adjusting the pH value of the suspension to 6.5-7.5, and then stirring at room temperature, finally subjecting the suspension to a hydrothermal reaction, washing the obtained product several times and then drying, to obtain a BiVO4 / Bi2MoO6 heterojunction piezoelectric catalyst.

[0006] Further, the dosage ratio of NH4VO3, Na2MoO4·2H2O, NaOH solution, Bi(NO3)3·5H2O, dilute HNO3 solution and sodium dodecylbenzenesulfonate is (0.117-0.234) g: (0.242 -0.484) g: 30 ml: (1.4552-2.4254) g: 30 ml: 0.5 g. Preferably, the pH value of the suspension is adjusted to 7.

[0007] Furthermore, the stirring speed is 450 r / min-460 r / min, and the stirring time is 30 min-40 min.

[0008] More preferably, the stirring speed is 450 r / min and the stirring time is 30 min.

[0009] Furthermore, the temperature of the hydrothermal reaction is 160°C -180°C, and the hydrothermal reaction time is 10 h -12 h.

[0010] Further preferably, the temperature of the hydrothermal reaction is 160 ºC and the hydrothermal reaction time is 12 h.

[0011] Furthermore, the drying temperature is 60°C-80°C, and the drying time is 10 h-12 h.

[0012] More preferably, the drying temperature is 60° C. and the drying time is 12 h.

[0013] Furthermore, the obtained product is washed with water and anhydrous ethanol.

[0014] Furthermore, the volume ratio of the mixed solution A to the mixed solution B is 1:1.

[0015] The present invention also provides a piezoelectric heterojunction catalyst prepared by the above-mentioned piezoelectric heterojunction catalyst preparation method, wherein the piezoelectric heterojunction catalyst is in the form of dispersed nanosheets.

[0016] The present invention also provides application of the piezoelectric heterojunction catalyst in producing hydrogen peroxide.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for preparing a piezoelectric heterojunction catalyst. A heterojunction piezoelectric catalyst of BiVO4 and Bi2MoO6 with different phase ratios is synthesized by a one-step hydrothermal method. During the preparation process, a surfactant, sodium dodecylbenzene sulfonate, is added to make the prepared catalyst have a dispersed nanosheet morphology. This morphology helps to increase the specific surface area of ​​the catalyst, expose more active sites, generate a stronger piezoelectric response, and improve its catalytic activity, thereby facilitating a piezoelectric catalytic reaction. In addition, the one-step hydrothermal synthesis allows BiVO4 and Bi2MoO6 to be closely combined to form a heterojunction, and the built-in electric field generated by the heterojunction is used to suppress electron-hole recombination, thereby improving the separation efficiency of carriers, so that the piezoelectric catalytic H2O2 production performance of the finally prepared BiVO4 / Bi2MoO6 heterojunction piezoelectric catalyst is much higher than that of pure phase BiVO4 and Bi2MoO6. Adjusting the pH value of the suspension to within the range of 6.5-7.5 is conducive to forming a stable suspension and preventing precipitation or agglomeration. It is also conducive to the subsequent hydrothermal reaction and the formation of the catalyst. Adjusting the pH value to 6.5-7.5 is also conducive to forming the phase structure of the catalyst and the dispersed nanosheet morphology.

[0018] Furthermore, by precisely controlling the dosage ratio of NH4VO3, Na2MoO4·2H2O, NaOH solution, Bi(NO3)3·5H2O, dilute HNO3 solution and sodium dodecylbenzene sulfonate, it is possible to ensure that the catalyst has uniform composition and stable structure, thereby improving its catalytic efficiency and service life. At the same time, the preparation method of the present invention only needs to simply regulate the ratio of V and Mo sources in the precursor to obtain piezoelectric heterojunction catalysts with different phase ratios, which is more suitable for industrial production. The reason why BiVO4 and Bi2MoO6, both of which are Bi-based compounds, are selected as reactants is that both have suitable energy band structures and can be synthesized using the hydrothermal method, which provides feasibility for the one-step hydrothermal synthesis of heterojunction piezoelectric catalysts.

[0019] Furthermore, by controlling the stirring speed within the range of 450 r / min-460 r / min and the stirring time within the range of 30 min-40 min, it is possible to ensure that the components in the suspension are fully mixed and uniform, which is conducive to forming a uniform catalyst structure.

[0020] Furthermore, the temperature of the hydrothermal reaction is controlled within the range of 160°C -180°C and the reaction time is 10 h -12 h, which can ensure the full crystallization and structural stability of the catalyst, and is also conducive to improving its piezoelectric properties and catalytic activity. At the same time, the preparation method has a low hydrothermal temperature, a short time, no secondary hydrothermal reaction is required, and the preparation process is simple.

[0021] Furthermore, by setting the drying temperature to 60 ℃-80 ℃ and the drying time to 10 h -12 h, it can be ensured that the moisture in the catalyst is fully volatilized, while preventing its structural damage due to excessive temperature, thereby maintaining its good catalytic performance.

[0022] Furthermore, by washing the obtained product with water and anhydrous ethanol, impurities and unreacted substances on the catalyst surface can be removed, thereby improving its purity and catalytic efficiency.

[0023] Furthermore, by controlling the volume ratio of the mixed solution A and B to 1:1, it can be ensured that the components in the two solutions are fully mixed, which is conducive to forming a uniform catalyst structure.

[0024] The present invention also provides a piezoelectric heterojunction catalyst prepared by the above preparation method, which has a dispersed nanosheet morphology, which is conducive to increasing the specific surface area of ​​the catalyst and improving its contact area with the reactants, thereby improving its catalytic efficiency.

[0025] The present invention also provides the use of the above-mentioned piezoelectric heterojunction catalyst in the production of hydrogen peroxide. Experimental measurements show that the yield of hydrogen peroxide produced by the piezoelectric heterojunction catalyst of the present invention is as high as 636 μmol.g -1 .h -1 . BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 1 are XRD patterns of heterojunction piezoelectric catalysts prepared in different comparative examples and examples, wherein (a) comparative example 1, (b) comparative example 2, (c) example 1, (d) example 2, and (e) example 3; Figure 2 is a SEM image of the heterojunction piezoelectric catalyst prepared in Example 2; Figure 3 are SEM images of Comparative Example 1 and Comparative Example 2, wherein (a) Comparative Example 1, (b) Comparative Example 2; Figure 4 are performance diagrams of piezoelectric catalytic H2O2 production of heterojunction piezoelectric catalysts prepared in different comparative examples and examples, wherein (a) comparative example 1, (b) comparative example 2, (c) example 1, (d) example 2, and (e) example 3; Figure 5 It is a mechanism diagram of the piezoelectric catalytic production of H2O2 by the BiVO4 / Bi2MoO6 heterojunction catalyst prepared in the present invention. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0028] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0029] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0030] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0031] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0032] A method for preparing a piezoelectric heterojunction catalyst for producing hydrogen peroxide comprises the following steps: Step 1: Mix NH4VO3 and Na2MoO4·2H2O and dissolve them in NaOH solution and stir for 10-20 minutes to completely dissolve them to obtain a mixed solution A; Step 2: Dissolve Bi(NO3)3·5H2O in dilute HNO3 solution to prepare mixed solution B; Step 3: Mix the mixed solution A in step (a) with the mixed solution B obtained in step (b) by slow dropwise addition under vigorous stirring to obtain a suspension, add a surfactant sodium dodecylbenzene sulfonate (SDBS) to the suspension, and adjust the pH of the suspension to 6.5-7.5 with a NaOH solution, then stir at room temperature at 450 r / min for 30 min, pour the obtained suspension into a 100 ml hydrothermal kettle, set the oven parameters to 160 ° C for 12 h, separate the suspension after the reaction is completed, and then wash it with water and anhydrous ethanol several times, and finally put the washed sample into a 60 ° C oven for 12 h to obtain a BiVO4 / Bi2MoO6 heterojunction piezoelectric catalyst.

[0033] The present invention adopts a one-step hydrothermal method to prepare BiVO4 / Bi2MoO6 heterojunction piezoelectric catalysts with different phase ratios by adjusting the dosage ratio of different NH4VO3 and Na2MoO4.2H2O. The built-in electric field generated by the heterojunction is used to suppress electron-hole recombination and improve the separation efficiency of carriers. The finally prepared BiVO4 / Bi2MoO6 heterojunction exhibits excellent piezoelectric catalytic performance in producing H2O2.

[0034] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0035] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0036] Comparative Example 1 Single-phase BiVO4 is prepared by hydrothermal method. The specific steps are as follows: Step 1: Add 0.117 g of NH4VO3 into 30 ml of 1 M NaOH solution and stir for 15 min to completely dissolve it to prepare mixed solution A; Step 2: Add 0.4851 g of Bi(NO3)3.5H2O to 30 ml of 2 M dilute HNO3 and stir for 15 min to completely dissolve it to prepare mixed solution B; Step 3: Mix the mixed solution A in step (1) with the mixed solution B in step (2) in a volume ratio of 1:1 by slowly dropping under vigorous stirring to obtain a suspension, add 0.5 g of a surfactant sodium dodecylbenzene sulfonate (SDBS) to the suspension, adjust the pH of the suspension to 7 with a 2 M NaOH solution, and then stir at room temperature and 450 r / min for 30 min; Step 4: Pour the suspension obtained in step 3 into a 100 ml hydrothermal autoclave, set the oven parameters to 160 °C for 12 h, and separate the suspension after the reaction is completed; then wash it with water and anhydrous ethanol several times, and finally put the washed sample into a 60 °C oven for 12 h to obtain BiVO4 powder.

[0037] Comparative Example 2 Single-phase Bi2MoO6 was prepared by hydrothermal method. The specific steps are as follows: Step 1: Add 0.242 g of Na2MoO4·2H2O into 30 ml of 1 M NaOH solution and stir for 15 min to completely dissolve it to prepare mixed solution A; Step 2: Add 0.4851 g of Bi(NO3)3·5H2O into 30 ml of 2 M dilute HNO3 and stir for 15 min to completely dissolve it to prepare mixed solution B; Step 3: Mix the mixed solution A in step (1) with the mixed solution B in step (2) in a volume ratio of 1:1 by slowly dropping under vigorous stirring to obtain a suspension, add 0.5 g of a surfactant sodium dodecylbenzene sulfonate (SDBS) to the suspension, adjust the pH of the suspension to 7 with a 2 M NaOH solution, and then stir at room temperature and 450 r / min for 30 min; Step 4: Pour the suspension obtained in step 3 into a 100 ml hydrothermal autoclave, set the oven parameters to 160 °C for 12 h, and separate the suspension after the reaction is completed; then wash it with water and anhydrous ethanol several times, and finally put the washed sample into a 60 °C oven and dry it for 12 h to obtain Bi2MoO6 powder.

[0038] Example 1 Step 1: Add 0.117 g of NH4VO3 and 0.484 g of Na2MoO4·2H2O into 30 ml of 1 M NaOH solution and stir for 10 min to completely dissolve them to prepare mixed solution A; Step 2: Add 2.4254 g of Bi(NO3)3·5H2O into 30 ml of 2 M dilute HNO3 and stir for 10 min to completely dissolve it to prepare mixed solution B; Step 3: Mix the mixed solution A in step (1) with the mixed solution B in step (2) in a volume ratio of 1:1 by slowly dropping under vigorous stirring to obtain a suspension, add 0.5 g of a surfactant sodium dodecylbenzene sulfonate (SDBS) to the suspension, adjust the pH of the suspension to 6.5 with a 2 M NaOH solution, and then stir at room temperature and 455 r / min for 35 min; Step 4: Pour the suspension obtained in step 3 into a 100 ml hydrothermal autoclave, set the oven parameters to 170 °C for 10 h, and separate the suspension after the reaction is completed; then wash it with water and anhydrous ethanol several times, and finally put the washed sample into a 70 °C oven for 10 h to obtain BiVO4 / Bi2MoO6 with a molar ratio of 0.5:1.

[0039] Example 2 Step 1: Add 0.117 g of NH4VO3 and 0.242 g of Na2MoO4·2H2O into 30 ml of 1 M NaOH solution and stir for 15 min to completely dissolve them to prepare mixed solution A; Step 2: Add 1.4552 g of Bi(NO3)3·5H2O into 30 ml of 2 M dilute HNO3 and stir for 15 min to completely dissolve it to prepare mixed solution B; Step 3: The mixed solution in step (a) is mixed with the mixed solution B in step (b) in a volume ratio of 1:1 by slowly dropping under vigorous stirring to obtain a suspension, 0.5 g of a surfactant sodium dodecylbenzene sulfonate (SDBS) is added to the suspension, and the pH of the suspension is adjusted to 7 with a 2 M NaOH solution, and then stirred at room temperature and 450 r / min for 30 min; Step 4: Pour the suspension obtained in step 3 into a 100 ml hydrothermal autoclave, set the oven parameters to 160 °C for 12 h, and separate the suspension after the reaction is completed; then wash it with water and anhydrous ethanol several times, and finally put the washed sample into a 60 °C oven for 12 h to obtain BiVO4 / Bi2MoO6 with a molar ratio of 1:1.

[0040] Example 3 Step 1: Add 0.234 g of NH4VO3 and 0.242 g of Na2MoO4·2H2O into 30 ml of 1 M NaOH solution and stir for 20 min to completely dissolve them to prepare mixed solution A; Step 2: Add 1.9403 g of Bi(NO3)3·5H2O into 30 ml of 2 M dilute HNO3 and stir for 20 min to completely dissolve it to prepare mixed solution B; Step 3: The mixed solution in step (a) is mixed with the mixed solution B in step (b) in a volume ratio of 1:1 by slowly dropping under vigorous stirring to obtain a suspension, 0.5 g of a surfactant sodium dodecylbenzene sulfonate (SDBS) is added to the suspension, and the pH of the suspension is adjusted to 7.5 with a 2 M NaOH solution, and then stirred at room temperature and 460 r / min for 40 min; Step 4: Pour the suspension obtained in step 3 into a 100 ml hydrothermal autoclave, set the oven parameters to 180 °C for 11 h, and separate the suspension after the reaction is completed; then wash it with water and anhydrous ethanol several times, and finally put the washed sample into an oven at 80 °C for 11 h to obtain BiVO4 / Bi2MoO6 with a molar ratio of 2:1.

[0041] from Figure 1 It can be seen that the diffraction peaks of the heterojunction piezoelectric catalysts prepared in all embodiments are consistent with the standard PDF card of BiVO4 (JCPDS 14-0133) and the standard PDF card of Bi2MoO6 (JCPDS 72-1524), no other impurities appear, and the characteristic diffraction peak intensity of BiVO4 increases with the increase of NH4VO3 content in the precursor.

[0042] from Figure 2 and Figure 3 It can be seen from the scanning image that the 1:1-BiVO4 / Bi2MoO6 catalyst sample prepared by the one-step hydrothermal method of the present invention has an ultra-thin, dispersed nanosheet morphology, while the nanosheet morphology of the single-phase BiVO4 and Bi2MoO6 prepared in Comparative Example 1 and Comparative Example 2 is not as thin as the nanosheet morphology of the catalyst prepared by the preparation method of the present invention, which means that the heterojunction sample prepared by the present invention can be more easily deformed when subjected to external mechanical force, thereby producing a stronger piezoelectric response; at the same time, the nanosheet morphology can expose more active sites, which is beneficial to the piezoelectric catalytic reaction.

[0043] from Figure 4 The performance diagram of piezoelectric catalytic production of H2O2 shows that under ultrasonic conditions, the yield of H2O2 produced by the piezoelectric catalytic single-phase BiVO4 prepared in Comparative Example 1 (a) is 56 μmol.g -1 .h -1 The yield of H2O2 produced by the piezoelectric catalysis of the single-phase Bi2MoO6 prepared in Comparative Example 2 (b) was 102 μmol.g -1 .h -1 ; The piezoelectric catalytic H2O2 yield of BiVO4 / Bi2MoO6 prepared in Example 1 (c) is 198 μmol.g -1 .h -1; The piezoelectric catalytic H2O2 yield of BiVO4 / Bi2MoO6 prepared in Example 2 (d) is 354 μmol.g -1 .h -1 ; The piezoelectric catalytic H2O2 yield of BiVO4 / Bi2MoO6 obtained in Example 3 (e) is 636 μmol.g -1 .h -1 It can be seen that the piezoelectric catalytic H2O2 production rate of the composite sample BiVO4 / Bi2MoO6 prepared in the present invention is as high as 636μmol.g -1 .h -1 , which is 11.3 times that of pure BiVO4 and 6.2 times that of pure Bi2MoO6.

[0044] like Figure 5 As shown in the figure, it is a reaction mechanism diagram of BiVO4 / Bi2MoO6 heterojunction piezoelectric catalysis to produce H2O2. When the material is deformed by external mechanical force, a polarized electric field is formed inside it, which stimulates the generation and separation of electrons and holes. Under the action of the built-in electric field, the electrons on the conduction band of Bi2MoO6 flow to the conduction band of BiVO4, and the electrons react with oxygen in the water to generate H2O2, while the holes on the valence band of BiVO4 flow to the valence band of Bi2MoO6, and then react with water to generate H2O2. The two form a heterojunction to promote the migration efficiency of carriers.

[0045] This fully demonstrates the successful preparation of the heterojunction and the formation of a tightly bound heterointerface between the BiVO4 and Bi2MoO6 phases. The built-in electric field generated by the heterojunction is used to suppress electron-hole recombination and promote the separation efficiency of carriers, providing an effective strategy for the development of piezoelectric catalysts with efficient piezoelectric catalytic H2O2 production performance.

[0046] The BiVO4 / Bi2MoO6 heterojunction piezoelectric catalyst prepared by the one-step hydrothermal method of the present invention has a low hydrothermal reaction temperature, a short time, a simple preparation process, and is suitable for industrial production. The prepared BiVO4 / Bi2MoO6 heterojunction piezoelectric catalyst has many active sites, a stronger piezoelectric response, a higher carrier separation efficiency, and a high-efficiency piezoelectric catalytic H2O2 production performance.

[0047] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a piezoelectric heterojunction catalyst, characterized in that: The following steps are involved: NH4VO3 and Na2MoO4·2H2O were mixed and dissolved in NaOH solution to prepare mixed solution A; Dissolve Bi(NO3)3·5H2O in dilute HNO3 solution to prepare mixed solution B; Mixing the mixed solution A and the mixed solution B to obtain a suspension; Sodium dodecylbenzene sulfonate is added to the suspension, and the pH value of the suspension is adjusted to 6.5-7.5, and then stirred, and finally a hydrothermal reaction is carried out, and the obtained product is washed and dried to obtain a BiVO4 / Bi2MoO6 heterojunction piezoelectric catalyst.

2. The method for preparing a piezoelectric heterojunction catalyst according to claim 1, characterized in that: The dosage ratio of NH4VO3, Na2MoO4·2H2O, NaOH solution, Bi(NO3)3·5H2O, dilute HNO3 solution and sodium dodecylbenzenesulfonate is (0.117-0.234) g: (0.242 -0.484) g: 30 ml: (1.4552 -2.4254) g: 30 ml: 0.5 g.

3. The method for preparing a piezoelectric heterojunction catalyst according to claim 1, characterized in that: The pH of the suspension was adjusted to 7.

4. The method for preparing a piezoelectric heterojunction catalyst according to claim 1, characterized in that: The stirring speed is 450 r / min-460 r / min, and the stirring time is 30 min-40 min.

5. The method for preparing a piezoelectric heterojunction catalyst according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 160°C -180°C, and the hydrothermal reaction time is 10 h -12 h.

6. The method for preparing a piezoelectric heterojunction catalyst according to claim 1, characterized in that: The drying temperature is 60 ℃-80 ℃, and the drying time is 10 h -12 h.

7. The method for preparing a piezoelectric heterojunction catalyst according to claim 1, characterized in that: The obtained product was washed with water and anhydrous ethanol.

8. The method for preparing a piezoelectric heterojunction catalyst according to claim 1, characterized in that: The volume ratio of the mixed solution A to the mixed solution B is 1:

1.

9. The piezoelectric heterojunction catalyst prepared by the method for preparing a piezoelectric heterojunction catalyst according to any one of claims 1 to 8, characterized in that: The piezoelectric heterojunction catalyst is in the form of dispersed nanosheets.

10. Use of the piezoelectric heterojunction catalyst according to claim 9 in producing hydrogen peroxide.

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