Atomic sharing Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst as well as preparation method and application thereof

Abstract

The invention provides an atom sharing Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric electro-catalyst as well as a preparation method and application thereof, and belongs to the technical field of piezoelectric electro-catalytic materials and environmental remediation. The preparation method comprises the following steps: uniformly dispersing Co3O4, a bismuth source and a reducing agent in a solvent I to obtain a solution A; uniformly dispersing Na2WO4. 2H2O and a template agent in a solvent II to obtain a solution B; and adding the solution B into the solution A, uniformly mixing, and carrying out a heating reaction to obtain the atom sharing Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst. The preparation method provided by the invention is simple, the raw materials are non-toxic and harmless, the preparation process is pollution-free, green and environment-friendly, and the catalyst has the advantages of high efficiency, convenience and controllability, and the prepared catalyst has excellent piezoelectric electro-catalytic degradation performance and good stability and can effectively remove antibiotic pollutants in a water environment.

Description

Technical Field

[0001] The present invention relates to the technical field of piezoelectric photocatalytic materials and environmental restoration, and in particular to an atom-sharing Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst and a preparation method and application thereof. Background Art

[0002] With the rapid development of industrialization, the production and discharge of emerging organic pollutants such as dyes, heavy metals, and antibiotics have posed a serious threat to aquatic ecosystems, especially tetracycline (TC), an antibiotic with anti-metabolism ability, which is widely present on the soil surface and even in drinking water, posing a serious threat to human health and the living environment. At present, conventional technologies for pharmaceutical wastewater treatment mainly include biodegradation, Fenton oxidation, and adsorption. Although these technologies have made some progress in the control of pharmaceutical pollution, their respective limitations are also obvious. For example, chemical oxidation methods (such as Fenton oxidation) are costly and have strict operating requirements. The stability of biological methods needs to be improved, and there is a problem of secondary pollution. Physical adsorption methods only transfer pollutants to other media and cannot fundamentally eliminate pollution.

[0003] In this context, Bi2WO6, as a semiconductor material with moderate band gap, good photoactivity and environmental friendliness, is increasingly used in the field of photocatalysis. However, problems such as high recombination rate of photogenerated electrons and holes and weak visible light absorption limit its application as a low-cost semiconductor photocatalyst. Summary of the invention

[0004] Based on the above content, the purpose of the present invention is to provide an atomically shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst and its preparation method and application. The present invention constructs a heterojunction structure and combines the surface plasmon resonance (LSPR) effect to effectively improve the separation efficiency of photogenerated holes and electrons and the visible light absorption capacity of the composite material, thereby enhancing the piezoelectric photocatalytic performance of the composite material.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention is a method for preparing an atomically shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst, comprising the following steps:

[0007] Co3O4, bismuth source and reducing agent are uniformly dispersed in solvent I to obtain liquid A; Na2WO4·2H2O and template agent are uniformly dispersed in solvent II to obtain liquid B; liquid B is added to liquid A and mixed evenly and then heated to react to obtain the atomic shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst.

[0008] The second technical solution of the present invention is an atomically shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst prepared by the above-mentioned preparation method.

[0009] The third technical solution of the present invention is the application of the above-mentioned atomic-sharing Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst in the piezoelectric photocatalytic degradation of antibiotics.

[0010] The present invention discloses the following technical effects:

[0011] 1. The preparation method of the Bi-Bi2WO6 / Co3O4 heterojunction of the present invention is simple, the raw materials are non-toxic and harmless, the preparation process is pollution-free, green and environmentally friendly, and has the advantages of high efficiency, convenience and controllability.

[0012] 2. The Bi-Bi2WO6 / Co3O4 heterojunction prepared by the present invention synergistically enhances the charge separation efficiency and visible light absorption capacity through the built-in electric field / piezoelectric effect and surface plasmon resonance effect, reduces the recombination rate of photogenerated carriers, and thus makes the Bi-Bi2WO6 / Co3O4 heterojunction have efficient piezoelectric photocatalytic degradation performance.

[0013] 3. The Bi-Bi2WO6 / Co3O4 heterojunction of the present invention has excellent piezoelectric photocatalytic degradation performance and good stability, can effectively remove antibiotic pollutants in water environments, and has broad practical application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 (A) and (B) are XRD patterns of different catalyst samples in the present invention;

[0016] Figure 2 (A) and (B) are FT-IR spectra of different catalyst samples in the present invention;

[0017] Figure 3 The XPS full spectra (A) and high-resolution spectra (B) Bi 4f, (C) W 4f, (D) Co 2p of BWO, Co3O4, Bi-BWO, BWO / CO-2 and Bi-BWO / CO-2 in the present invention;

[0018] Figure 4are electron microscope images of different catalyst samples prepared in the present invention, wherein A is the SEM image of BWO, B is the SEM image of Co3O4, C is the SEM image of Bi-BWO / CO-2, D and E are TEM images of Bi-BWO / CO-2, F is the SAED image of Bi-BWO / CO-2, and G is the element mapping image of Bi-BWO / CO-2;

[0019] Figure 5 The UV-Vis diffuse reflectance spectra of different catalyst samples in the present invention;

[0020] Figure 6 is the photoluminescence spectra of different catalyst samples in the present invention;

[0021] Figure 7 The piezoelectric photocatalytic degradation performance and reaction condition optimization diagram of different catalyst samples; A and B are the piezoelectric photocatalytic degradation performance of different catalyst samples for tetracycline and the corresponding K value; the influence of different operating parameters on the Bi-BWO / CO-2 piezoelectric photocatalytic degradation system: catalyst dosage C; initial TC concentration D; pH value E; different antibiotic pollutants F;

[0022] Figure 8 This is an experiment on the recycling of tetracycline by piezoelectric photocatalytic degradation of Bi-BWO / CO-2 heterojunction. DETAILED DESCRIPTION

[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0024] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0025] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0026] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0027] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0028] Room temperature in the present invention means 15-35°C.

[0029] Constructing a heterojunction structure is an effective strategy to improve the visible light response capability of semiconductors and reduce the bandgap width. Among them, Bi2WO6 is a typical layered bismuth-based piezoelectric material. Its built-in electric field generated by polarization can effectively suppress carrier recombination and show good piezoelectric photocatalytic performance. Therefore, the development of new Bi2WO6-based piezoelectric photocatalytic materials will not only help solve existing technical problems, but also bring new breakthroughs and progress to the field of pharmaceutical wastewater treatment.

[0030] Specifically, the present invention provides a method for preparing an atomically shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst, comprising the following steps:

[0031] Co3O4, bismuth source and reducing agent are uniformly dispersed in solvent I to obtain liquid A; Na2WO4·2H2O and template agent are uniformly dispersed in solvent II to obtain liquid B; liquid B is added to liquid A and mixed evenly and then heated to react to obtain the atomic shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst.

[0032] In some embodiments of the present invention, the method for preparing Co3O4 comprises the following steps:

[0033] The mixed solution of uniformly dispersed Co(NO3)2·6H2O and CTAB was poured into the 2-methylimidazole solution and stirred to react to obtain ZIF-67;

[0034] The ZIF-67 is calcined to obtain the Co3O4.

[0035] Different from the dodecahedral ZIF-67 prepared by the classical preparation method, the ZIF-67 prepared by the preparation method provided by the present invention has a cubic structure. The Co3O4 prepared by the ZIF-67 in the present invention has more catalytic active sites and better catalytic activity as a carrier loaded with Bi2WO6.

[0036] In some embodiments of the present invention, the solvent used to uniformly disperse the mixed solution of Co(NO3)2·6H2O and CTAB is water; in the mixed solution, the concentration of Co(NO3)2·6H2O is 27-33 g / L, the concentration of CTAB is 0.5 g / L; the concentration of the 2-methylimidazole solution is 60-70 g / L; the volume ratio of the mixed solution to the 2-methylimidazole solution is 1:7. The present invention uses CTAB as a template to form a cubic ZIF-67 with a specific morphology.

[0037] In some embodiments of the present invention, the stirring reaction is carried out at room temperature for 30 minutes.

[0038] In some embodiments of the present invention, after the stirring reaction is completed, the steps of centrifugation, washing and drying are further included; the drying temperature is 80° C. and the drying time is 12 hours.

[0039] In some embodiments of the present invention, the calcination temperature is 300-400°C, the time is 2-3h, and the heating rate during calcination is 5°C / min.

[0040] In some embodiments of the present invention, the specific steps of uniformly dispersing the Co3O4, Bi(NO3)3·5H2O and the reducing agent in solvent I are as follows: uniformly dispersing Co3O4 in solvent I to obtain solution A, uniformly dispersing Bi(NO3)3·5H2O and the reducing agent in solvent II to obtain solution B, and then uniformly mixing solution A and solution B. Both solvent I and solvent II are ethylene glycol.

[0041] In some embodiments of the present invention, when adding the liquid B to the liquid A, the adding method is to add slowly and stir vigorously until the liquid is evenly dispersed.

[0042] In some embodiments of the present invention, the bismuth source is Bi(NO3)3·5H2O; the reducing agent is glucose; the concentration of Co3O4 in the liquid A is 0.6-2.5 g / L, the concentration of Bi(NO3)3·5H2O is 24-26 g / L, and the concentration of glucose is 8.5-9.5 g / L; the template is CTAB; the concentration of Na2WO4·2H2O in the liquid B is 8-10 g / L, and the concentration of CTAB is 1-2 g / L; the volume ratio of the liquid A to the liquid B is 1:1. The present invention uses CTAB as a template to make the prepared Bi2WO6 present a layered structure and increase the active sites.

[0043] In the present invention, if the concentrations of Co3O4, Bi(NO3)3·5H2O in solution A and the concentrations of Na2WO4·2H2O and CTAB in solution B are not within the above parameter ranges, the subsequent solvothermal reaction will be incomplete, the catalytic activity of the sample will be reduced, or even inactivated.

[0044] In some embodiments of the present invention, the heating reaction is carried out at a temperature of 110 to 140° C. and for a time of 22 to 26 hours.

[0045] In the present invention, if the heating reaction temperature is too low, the preparation of Bi2WO6 will fail, and if it is too high, the morphology will be destroyed, resulting in decreased activity; if the heating reaction time is too short, Bi2WO6 may fail to be prepared. In order to obtain a highly active catalyst, the reaction parameters of the present invention are preferably within the above parameter range.

[0046] In some embodiments of the present invention, after the heating reaction is completed, the steps of cooling, filtering, washing and drying the obtained product are also included; the drying temperature is 60 to 80° C. and the drying time is 10 to 14 h.

[0047] The present invention also provides an atomic-shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst prepared by the above preparation method.

[0048] The present invention also provides the use of the above-mentioned atom-sharing Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst in piezoelectric photocatalytic degradation of antibiotics.

[0049] In some embodiments of the present invention, the antibiotic is at least one of tetracycline, oxytetracycline, ciprofloxacin and levofloxacin.

[0050] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0051] Unless otherwise specified, the raw materials and reagents used in the examples can be obtained through commercial channels.

[0052] The method for testing the piezoelectric photocatalytic activity of the catalyst in the embodiment of the present invention is:

[0053] A 300W xenon lamp with a 420nm cutoff filter was used as the light source, and an ultrasonic cleaner provided mechanical vibration. Piezoelectric photocatalytic activity was tested at room temperature. 30mg of catalyst and 50mL of tetracycline solution (20mg / L) were added to a 100mL quartz glass reactor in sequence. After dark stirring for 30min to reach adsorption-desorption equilibrium, the suspension was continuously reacted for 30min under ultrasonic vibration and xenon lamp irradiation. During this period, 3mL of the suspension was filtered with a 0.22μm filter membrane every 5min, and the absorbance at the maximum absorption wavelength of 357nm was recorded with a UV-visible spectrophotometer. The degradation rate was then further calculated.

[0054] Example 1

[0055] Preparation of Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst, the steps are as follows:

[0056] (1) Preparation of ZIF-67: First, accurately weigh 0.582 g (about 2 mmol) of Co(NO3)2·6H2O and dissolve it in 20 mL of distilled water containing 0.01 g of CTAB to obtain solution A; dissolve 9.08 g of 2-methylimidazole in 140 mL of distilled water to obtain solution B. Then, solution A was quickly poured into solution B and stirred at room temperature for 30 min. The product was collected by centrifugation, washed with ethanol three times, and then dried at 80°C for 12 h to obtain ZIF-67 powder.

[0057] (2) Preparation of Co3O4: ZIF-67 powder was placed in an air furnace at 5°C min -1 The temperature is increased at a heating rate until a predetermined temperature of 350°C is reached, and annealing is performed at this temperature for 2 hours to obtain Co3O4.

[0058] (3) Preparation of Bi-Bi2WO6 / Co3O4 heterojunction: 0.025g Co3O4 was uniformly dispersed in 20mL ethylene glycol solution and ultrasonically treated for 30min to obtain solution A. 0.97g Bi(NO3)3·5H2O+0.36g glucose was uniformly dispersed in 20mL ethylene glycol solution and ultrasonically treated for 30min to obtain solution B. Subsequently, solution A and solution B were mixed and stirred for 30min to obtain solution A. 1mmol (0.33g) Na2WO4·2H2O and 0.05g CTAB were uniformly dispersed in 40mL water to obtain solution B. Solution B was slowly added to solution A and stirred vigorously at room temperature for 1h. Subsequently, the obtained mixed solution was placed in a 100mL autoclave and reacted at 120℃ for 24h. After the reaction was completed, it was naturally cooled to room temperature, filtered to obtain the precipitate, and washed with deionized water and ethanol three times respectively, and finally dried at 80℃ for 12h. The obtained product was designated as Bi-BWO / CO-1.

[0059] When the catalyst was Bi-BWO / CO-1 and the reaction was carried out for 30 min, the degradation rate of tetracycline was 92.4%.

[0060] When the catalyst is Co3O4 obtained in step 2, the degradation rate of tetracycline is 32.57% after the reaction is carried out for 30 minutes.

[0061] Comparative Example 1

[0062] 1. Preparation of Bi2WO6, the steps are as follows:

[0063] First, accurately weigh 2mmol (0.97g) Bi(NO3)3·5H2O, 1mmol (0.33g) Na2WO4·2H2O and 0.05g CTAB. Add them to a mixed solution containing 40mL distilled water and 40mL ethylene glycol in sequence, followed by 20min of ultrasonic treatment. Then, stir vigorously at room temperature for 1h. Then transfer the mixed solution to a 100mL autoclave and react at 120℃ for 24h. After the reaction is completed, cool naturally to room temperature, filter to obtain a white precipitate, wash it with deionized water and ethanol three times respectively, and finally dry it at 80℃ for 12h. The obtained product is recorded as BWO.

[0064] When the catalyst is BWO and the reaction is carried out for 30 min, the degradation rate of tetracycline is 70.99%.

[0065] Comparative Example 2

[0066] The preparation method of the Bi2WO6 / Co3O4 catalyst provided in this comparative example is the same as that in Example 1, the only difference is that 0.025g Co3O4 is replaced by 0.05g Co3O4, and glucose is not added as a reducing agent. The obtained product is recorded as BWO / CO-2.

[0067] When the catalyst is BWO / CO-2 and the reaction is carried out for 30 min, the degradation rate is 85.34%.

[0068] Comparative Example 3

[0069] The preparation method of the Bi-Bi2WO6 catalyst provided in this comparative example is the same as that of comparative example 1, except that 0.36 g of glucose is added as a reducing agent, and the obtained product is recorded as Bi-BWO.

[0070] When the catalyst is Bi-BWO, the degradation rate of tetracycline is 88.28% after the reaction is carried out for 30 min.

[0071] Example 2

[0072] The preparation method of the Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst provided in this embodiment is the same as that in Example 1, except that 0.025 g of Co3O4 is replaced by 0.05 g of Co3O4, and the obtained product is recorded as Bi-BWO / CO-2.

[0073] When the catalyst is Bi-BWO / CO-2 and the reaction is carried out for 30 min, the degradation rate of tetracycline is 97.14%.

[0074] The present invention also tests the degradation rate of Bi-BWO / CO-2 on antibiotics when the antibiotics are oxytetracycline, ciprofloxacin and levofloxacin solutions. The results show that when the reaction is carried out for 30 minutes, the degradation rates of Bi-BWO / CO-2 on oxytetracycline, ciprofloxacin and levofloxacin are 97.63%, 86.67% and 71.51% respectively.

[0075] Example 3

[0076] The preparation method of the Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst provided in this embodiment is the same as that in Example 1, except that 0.025 g of Co3O4 is replaced by 0.075 g of Co3O4, and the obtained product is recorded as Bi-BWO / CO-3.

[0077] When the catalyst is Bi-BWO / CO-3 and the reaction is carried out for 30 min, the degradation rate of tetracycline is 93.21%.

[0078] Example 4

[0079] The preparation method of the Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst provided in this embodiment is the same as that in Example 1, except that 0.025 g of Co3O4 is replaced by 0.1 g of Co3O4, and the obtained product is recorded as Bi-BWO / CO-4.

[0080] When the catalyst was Bi-BWO / CO-4 and the reaction was carried out for 30 min, the degradation rate of tetracycline was 89.82%.

[0081] Characterization results of the catalysts of Examples 1 to 4 and Comparative Examples 1 to 3:

[0082] The XRD patterns of different samples in the present invention are as follows: Figure 1As shown, the diffraction peaks of BWO are located at 28.4, 33.1, 47.5, 56.1, 58.9, 69.2, 76.5 and 79.1°, corresponding to (131), (200), (260), (331), (262), (400), (333) and (460) surfaces, and the data are consistent with the standard card (PDF#39-0256). In addition, the diffraction peaks of pure Co3O4 point to the (220), (311), (400), (422) and (440) planes of cubic phase Co3O4 (PDF#42-1467). The XRD pattern of Bi-BWO / CO is almost the same as that of BWO, and only the (311) and (400) planes of Co3O4 are observed, which proves that Bi-BWO / CO is successfully prepared, but the Co3O4 content is low.

[0083] The FT-IR spectra of different samples in the present invention are as follows: Figure 2 As shown, for Co3O4, there are two -1 The characteristic peaks of BWO at 568 and 761 cm -1 The strong characteristic peak at 1392cm -1 The weak peak at corresponds to WOW.

[0084] Figure 3 The full XPS spectra (A) and high-resolution spectra (B) Bi 4f, (C) W 4f and (D) Co 2p of BWO, Co3O4, Bi-BWO, BWO / CO-2 and Bi-BWO / CO-2 in the present invention. The full XPS spectrum shows that the composition of Bi-BWO / CO-2 is Bi, W, Co and O. In addition, in the high-resolution XPS spectrum of Bi 4f, two characteristic peaks appear at 164.13 and 158.80 eV, belonging to Bi 4f and Co 2p, respectively. 5 / 2 and Bi 4f 7 / 2 The W 4f peaks at 35.08 and 37.21 eV are similar to the W 4f 7 / 2 and W 4f 5 / 2 The peaks of Bi 4f and W 4f in Bi-BWO / CO-2 and BWO / CO-2 shift toward the low binding energy direction, indicating that the electron density has increased. Bi-BWO also shows the same trend, indicating that Bi metal can provide electrons for BWO. In Bi-BWO / CO-2 and BWO / CO-2, the high binding energy shift of Co 2p peak indicates a decrease in electron density, reflecting the strong interaction between BWO and Co3O4.

[0085] Figure 4It is an electron microscope image of different catalysts prepared in the present invention. The SEM image of BWO shows many uniformly distributed layered structures, while Co3O4 presents a regular hollow cubic morphology, giving it a larger specific surface area. In the composite of BWO and Co3O4 to form a Bi-BWO / CO-2 heterojunction, the originally regular hollow cubic structure suffered a certain degree of damage, which is also clearly visible in the TEM image. In addition, obvious lattice fringes were observed by HRTEM. In addition, the element mapping shows that Bi, W, Co and O elements are uniformly distributed, indicating that the active centers of the Bi-BWO / CO-2 heterojunction are uniformly distributed.

[0086] Figure 5 The UV-visible diffuse reflectance spectra of different samples in the present invention show that the formation of heterojunction structure can effectively adjust the band gap of photocatalytic materials.

[0087] Figure 6 The photoluminescence spectra of different catalyst samples in the present invention are shown in Figure 2. BWO and Co3O4 materials themselves exhibit strong PL emission characteristics, but when they are combined into the composite material Bi-BWO / CO-2, its PL intensity decreases, indicating that the recombination rate of photogenerated carriers is reduced.

[0088] Figure 7 The piezoelectric photocatalytic degradation performance and reaction condition optimization diagram of different catalyst samples; A and B are the piezoelectric photocatalytic degradation performance of different catalyst samples for tetracycline and the corresponding K value; the influence of different operating parameters on the Bi-BWO / CO-2 piezoelectric photocatalytic degradation system: catalyst dosage (C); initial TC concentration (D); pH value (E); different antibiotic pollutants (F). It can be seen from the figure that the Bi-Bi2WO6 / Co3O4 heterojunction prepared by the present invention exhibits excellent piezoelectric photocatalytic performance, and the removal efficiency of tetracycline can reach 97.14%; it also exhibits good piezoelectric photocatalytic degradation performance for other antibiotics.

[0089] Figure 8 This is a recycling experiment of Bi-BWO / CO-2 heterojunction piezoelectric photocatalytic degradation of tetracycline. The recovered catalyst sample was filtered, dried in an oven at 80°C for 12 hours, and then ground and stored for reuse. After five cycles of reuse experiments, the piezoelectric photocatalytic degradation efficiency of Bi-BWO / CO-2 was still greater than 90%.

[0090] In summary, the catalytic material obtained by the preparation method of the present invention has a hollow cubic structure and an adjustable band structure, which can effectively promote the rapid separation of photogenerated carriers at the junction interface, thereby improving its photocatalytic activity. The catalyst is applied to the piezoelectric photocatalytic degradation of tetracycline, and the degradation rate of tetracycline can reach 97.14% within 30 minutes. After five cycles of use, the piezoelectric photocatalytic degradation efficiency is still above 90%. In addition, the catalyst shows good versatility when other antibiotics are used as pollutant substrates. Therefore, the present invention has broad application prospects.

[0091] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing an atomically shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst, characterized in that: The following steps are involved: Co3O4, bismuth source and reducing agent are uniformly dispersed in solvent I to obtain liquid A; Na2WO4·2H2O and template agent are uniformly dispersed in solvent II to obtain liquid B; liquid B is added to liquid A and mixed evenly and then heated to react to obtain the atomic shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst.

2. The method for preparing the atomically shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst according to claim 1, characterized in that: The preparation method of Co3O4, The following steps are involved: The mixed solution of uniformly dispersed Co(NO3)2·6H2O and CTAB was poured into the 2-methylimidazole solution and stirred to react to obtain ZIF-67; The ZIF-67 is calcined to obtain the Co3O4.

3. The method for preparing the atomically shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst according to claim 2, characterized in that: In the mixed solution, the concentration of Co(NO3)2·6H2O is 27-33 g / L, and the concentration of CTAB is 0.5 g / L; the concentration of the 2-methylimidazole solution is 60-70 g / L; and the volume ratio of the mixed solution to the 2-methylimidazole solution is 1:

7.

4. The method for preparing the atomically shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst according to claim 2, characterized in that: The stirring reaction was carried out at room temperature for 30 minutes.

5. The method for preparing the atomically shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst according to claim 2, characterized in that: The calcination temperature is 300-400°C and the calcination time is 2-3h.

6. The method for preparing the atomically shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst according to claim 1, characterized in that: The bismuth source is Bi(NO3)3·5H2O; the reducing agent is glucose; the concentration of Co3O4 in the solution A is 0.6-2.5 g / L, the concentration of Bi(NO3)3·5H2O is 24-26 g / L, and the concentration of glucose is 8.5-9.5 g / L; the template agent is CTAB; the concentration of Na2WO4·2H2O in the solution B is 8-10 g / L, and the concentration of CTAB is 1-2 g / L; the volume ratio of the solution A to the solution B is 1:

1.

7. The method for preparing the atomically shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst according to claim 1, characterized in that: The temperature of the heating reaction is 110-140° C., and the time is 22-26 hours.

8. An atomically shared Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the atomic-sharing Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst according to claim 8 in piezoelectric photocatalytic degradation of antibiotics.

10. The use of the atomic-sharing Bi-Bi2WO6 / Co3O4 heterojunction piezoelectric photocatalyst according to claim 9 in piezoelectric photocatalytic degradation of antibiotics, characterized in that: The antibiotic is at least one of tetracycline, oxytetracycline, ciprofloxacin and levofloxacin.

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