S-type bismuth oxybromide / cesium tungsten bronze energy storage heterojunction and preparation method and application thereof

Abstract

The invention provides an S-type bismuth oxybromide / cesium tungsten bronze energy storage heterojunction as well as a preparation method and application thereof. The BiOBr / KxCs0.32-xWO3 S-type energy storage heterojunction is prepared by an electrostatic adsorption method of positive and negative charges generated by synergism of optical excitation and piezoelectric effect. The two piezoelectric crystals are compounded to enhance the piezoelectric response capability, the piezoelectric coefficient d33 of the piezoelectric crystals is increased to 56.27-79.92 nm * V <-1 >, and excitons can be formed on the interface of the piezoelectric crystals; the piezoelectric catalytic activity of the energy storage heterojunction is enhanced by enhanced redox piezoelectric potential and excitons formed on the interface. Under the synergistic effect of energy storage heterojunction enhanced redox piezoelectric potential, excitons formed on an interface, an energy storage heterojunction series polarization electric field and an interface S-type electric field, h < + >, e <->,. O < 2->, OH and < 1 > O < 2 > are formed to effectively degrade organic pollutants.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of piezoelectric catalytic functional material preparation, and particularly relates to an S-type bismuth oxybromide / cesium tungsten bronze energy storage heterojunction and a preparation method and application thereof. BACKGROUND

[0002] Bisphenol A (BPA) is a common chemical substance with biological toxicity and environmental persistent pollution, mainly from plastic products, food packaging, tobacco, etc. BPA will enter the environment with the discharge of garbage, polluting water bodies and soil, and can be detected in domestic sewage and effluent from sewage treatment plants. Its potential toxic hazards have caused serious negative impacts on the ecological environment and life health. Effective pollution control technology is urgently needed to completely remove BPA to avoid environmental pollution and health hazards. Photocatalytic technology has the advantages of economy, high efficiency and mild reaction conditions, and is considered as one of the effective treatment technologies for removing BPA in water.

[0003] Photocatalytic technology is driven by green solar energy to produce active oxygen species to achieve the degradation of BPA. However, it is severely dependent on light conditions, and the utilization rate of near-infrared light is low, so that photocatalytic technology cannot fully play its due role in some specific environments. Piezoelectric catalytic technology realizes photocatalysis without light by inducing polarization of piezoelectric materials through mechanical energy, but is limited by low piezoelectric coefficient of single piezoelectric crystal and high carrier recombination rate, so the piezoelectric catalytic activity is still low. To overcome these problems, constructing heterojunction is one of the effective ways to increase the piezoelectric catalytic and piezoelectric photocatalytic redox potential of piezoelectric crystals. The stable coupling between stress-induced piezoelectric field and interface polarization leads to a large intrinsic dipole moment, which enhances the surface piezoelectric potential. The polar field of the heterojunction structure is conducive to the reduction of Gibbs free energy, the increase of surface piezoelectric potential and the reduction of charge transfer resistance, which are helpful to high-activity piezoelectric catalysis and piezoelectric photocatalysis reactions.

[0004] Cesium tungsten bronze (Cs x WO3) is a non-stoichiometric compound, and its chemical formula can be expressed as Cs x WO3(0<X<0.33). In the structure of tungsten bronze (M x WO3), the introduction of cation Cs will introduce free electrons in the conduction band, and the electrons in the conduction band will displace the lattice ions and cause polarization, thereby generating W 5+ and W 6+ small polaron transition between them, while absorbing near-infrared light. Small polaron transition and near-infrared light absorption make it have potential applications in the field of catalysis, etc. However, Cs 0.32 WO3 has problems such as limited piezoelectric active sites and high carrier recombination rate (lifetime <5 ns), which restrict its practical application. Alkali metal-doped K x Cs0.32- x WO3 piezoelectric crystal, causing crystal distortion, reduced band gap and enhanced conduction band potential, K x Cs 0.32-x WO3 piezoelectric crystal piezophotocatalytic performance is enhanced. However, due to K x Cs 0.32-x WO3 crystal reduction potential, its K x Cs 0.32-x WO3 piezoelectric crystal energy storage piezocatalysis, piezophotocatalysis and piezophotocatalysis cycle stability is still not ideal. SUMMARY

[0005] In order to solve the above problems of the prior art, the present application provides an S-type bromine bismuth oxide / cesium tungsten bronze energy storage heterojunction and a preparation method and application thereof, to solve the problems of K x Cs 0.32-x WO3 piezoelectric crystal piezophotocatalytic activity and poor cycle stability.

[0006] The present application is realized by the following technical scheme: In a first aspect, the present application provides a preparation method of an S-type bromine bismuth oxide / cesium tungsten bronze energy storage heterojunction, comprising the following steps: Step 1, K x Cs 0.32-x WO3 and BiOBr are dispersed into ethanol to obtain K x Cs 0.32-x WO3 suspension and BiOBr suspension; Step 2, K x Cs 0.32-x WO3 suspension and BiOBr suspension are respectively subjected to ultraviolet irradiation under stirring conditions; Step 3, the BiOBr suspension after ultraviolet irradiation is poured into the K x Cs 0.32-x WO3 suspension after ultraviolet irradiation, and the obtained mixed suspension is subjected to ultraviolet irradiation under stirring conditions to obtain a precipitated powder; Step 4, the obtained precipitated powder is washed and dried to obtain an S-type bromine bismuth oxide / cesium tungsten bronze energy storage heterojunction.

[0007] Preferably, the molar ratio of BiOBr to K x Cs 0.32-x WO3 is 7:3~1:9.

[0008] Preferably, in step 2, the ultraviolet irradiation time is 30~60 min, and in step 3, the ultraviolet irradiation time is 3~6h.

[0009] Preferably, the K xCs 0.32-x The preparation method of WO3 is as follows: WCl6 powder, CsNO3 powder and KNO3 are dispersed into anhydrous ethanol, heated, mixed with a citric acid solution to obtain a purple turbid precursor solution; the purple turbid precursor solution is subjected to a solvothermal reaction, and the obtained product is washed and dried to obtain K x Cs 0.32-x WO3 powder.

[0010] Preferably, the preparation method of BiOBr is as follows: Bi(NO3)3·5H2O is added into water, and NaBr is added while stirring to obtain a mixed solution; the mixed solution is stirred at room temperature to form a uniform precursor solution; the precursor solution is subjected to a hydrothermal reaction to obtain a precipitate; the precipitate is washed and dried to obtain BiOBr powder.

[0011] In a second aspect, the application provides an S-type bismuth oxybromide / cesium tungsten bronze energy storage heterojunction obtained by the preparation method.

[0012] Preferably, in the S-type bismuth oxybromide / cesium tungsten bronze energy storage heterojunction, the cesium tungsten bronze crystal is a hexagonal phase K x Cs 0.32-x WO3 crystal, and the bismuth oxybromide is a tetragonal phase BiOBr with a space group P4(nmm).

[0013] Preferably, the piezoelectric coefficient d 33 of the S-type bismuth oxybromide / cesium tungsten bronze energy storage heterojunction is 56.27-79.92 nm·V -1 .

[0014] In a third aspect, the application provides an application of the S-type bismuth oxybromide / cesium tungsten bronze energy storage heterojunction in dark conditions for energy storage, piezoelectric catalysis and cyclic stable and efficient degradation of organic pollutants.

[0015] In a fourth aspect, the application provides an application of the S-type bismuth oxybromide / cesium tungsten bronze energy storage heterojunction in solar light or near-infrared light for energy storage, piezoelectric catalysis, piezophotocatalysis and cyclic stable degradation of organic pollutants.

[0016] Compared with the prior art, the application has the following beneficial effects: The application prepares BiOBr / K x Cs 0.32-x WO3 S-type energy storage heterojunction by electrostatic adsorption of positive and negative charges generated by synergistic effect of photoexcitation and piezoelectric effect. The combination of two piezoelectric crystals enhances the piezoelectric response capability, and the piezoelectric coefficient d 33 of the S-type energy storage heterojunction is increased to 56.27-79.92 nm·V -1, and excitons can be formed at the interface thereof; the enhanced redox piezoelectric potential and the excitons formed at the interface enhance the piezocatalytic activity of the energy storage heterojunction. Under the synergistic effect of the enhanced redox piezoelectric potential of the energy storage heterojunction, the excitons formed at the interface, the series polarization electric field of the energy storage heterojunction and the interface S-type electric field, the h + , e - , ·O2 - , OH and 1 O2 can effectively degrade organic pollutants.

[0017] The S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction can stably and efficiently degrade organic pollutants under dark conditions and full-spectrum light through energy storage piezocatalysis, piezophotocatalysis and piezocatalysis recycling, and has excellent recycling degradation stability. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 is the XRD graph of the energy storage heterojunction prepared in embodiments 1-5 of the present application; Figure 2 is the XRD data refinement graph of the energy storage heterojunction prepared in embodiments 1-5 of the present application; Figure 3 is the Raman graph of the energy storage heterojunction prepared in embodiments 1-5 of the present application; Figure 4 is the HRTEM graph of the energy storage heterojunction prepared in embodiment 3 of the present application; Figure 5 is the XPS graph of the energy storage heterojunction prepared in embodiment 4, embodiment 3, embodiment 2, comparative example 1 and comparative example 2 of the present application; Figure 6 is the XPS spectrum of O1s of the energy storage heterojunction prepared in embodiment 4, embodiment 3, embodiment 2, comparative example 1 and comparative example 2 of the present application; Figure 7XPS spectra of the energy storage heterojunction W 4f prepared in Example 4, Example 3, Example 2 and Comparative Example 1; Figure 8 XPS spectra of the energy storage heterojunction Cs 3d prepared in Example 4, Example 3, Example 2 and Comparative Example 1; Figure 9 XPS spectra of the energy storage heterojunction Bi 4f prepared in Example 4, Example 3, Example 2 and Comparative Example 2; Figure 10 XPS spectra of the energy storage heterojunction Br 3d prepared in Example 4, Example 3, Example 2 and Comparative Example 2; Figure 11 UV-vis diffuse reflectance spectra of the energy storage heterojunction prepared in Example 4, Example 3, Example 2, Comparative Example 1 and Comparative Example 2; Figure 12 BiOBr and K x Cs 0.32-x Valence band spectra of WO3; Figure 13 BiOBr and K x Cs 0.32-x Band gap width diagram of WO3; Figure 14 Piezoelectric force microscope (PFM) diagram and dark light transient piezoelectric current diagram of Example 3, Example 4 and Comparative Example 1; Figure 15 MB decolorization experiment diagram of the energy storage heterojunction of Example 1 of the present application; Figure 16 MB decolorization experiment diagram of the energy storage heterojunction of Example 2 of the present application; Figure 17 MB decolorization experiment diagram of the energy storage heterojunction of Example 3 of the present application; Figure 18 MB decolorization experiment diagram of the energy storage heterojunction of Example 4 of the present application; Figure 19 MB decolorization experiment diagram of the energy storage heterojunction of Example 5 of the present application; Figure 20 MB decolorization experiment diagram of Comparative Example 1; Figure 21 EPR-TEMPO-h + diagram prepared in Example 3 of the present application; Figure 22 The energy storage heterojunction prepared in Example 3, Example 4, Example 5 and the material of Comparative Example 1 and Comparative Example 2 is 20 mg·L -1 BPA piezoelectric catalytic degradation rate; Figure 23 The energy storage heterojunctions prepared in Examples 3, 4, and 5 of this invention, as well as the materials in Comparative Examples 1 and 2, were tested under dark conditions at 20 mg·L⁻¹. -1 BPA piezoelectric catalytic reaction degradation rate graph (0-1 min); Figure 24 The energy storage heterojunctions prepared in Examples 3, 4, and 5 of this invention, as well as the materials in Comparative Examples 1 and 2, were tested under dark conditions at 20 mg·L⁻¹. -1 BPA piezoelectric catalytic reaction degradation rate diagram from 1 to 7 min; Figure 25 Example 3: Energy storage heterojunction under dark conditions with 20 mg·L⁻¹ -1 BPA degradation and cycling performance; Figure 26 K is for Comparative Example 1 x Cs 0.32-x WO3 powder under dark conditions at 20 mg·L -1 BPA degradation and cycling performance; Figure 27 To simulate sunlight, the energy storage heterojunctions prepared in Examples 5, 3, and 1 of this invention, and the K-type heterojunction of Comparative Example 1, were used. x Cs 0.32-x WO3 powder at 20 mg·L -1 Degradation rate of BPA at concentration; Figure 28 To simulate sunlight, the energy storage heterojunctions prepared in Examples 5, 3, and 1 of this invention, and the K-type heterojunction of Comparative Example 1, were used. x Cs 0.32-x WO3 powder at 20 mg·L -1 Degradation rate of BPA concentration in piezoelectric photocatalytic reaction from 0 to 1 min; Figure 29 To simulate sunlight, the energy storage heterojunctions prepared in Examples 5, 3, and 1 of this invention, and the K-type heterojunction of Comparative Example 1, were used. x Cs 0.32-x WO3 powder at 20 mg·L -1 Degradation rate of BPA concentration in piezoelectric photocatalytic reaction from 1 to 9 min; Figure 30 The energy storage heterojunction pair prepared in Example 3 under simulated sunlight (20 mg·L⁻¹) -1 BPA cyclic degradation diagram; Figure 31 To compare K in Example 1 under simulated sunlight x Cs 0.32-x WO3 powder at 20 mg·L -1 BPA cyclic degradation diagram; Figure 32 K of the energy storage heterojunction prepared in Example 1, Example 2, Example 3, Example 4 of the present application and Comparative Example 1 under near-infrared light x Cs 0.32-x WO3powder to 20 mg·L -1 Degradation rate of BPA at different concentrations; Figure 33 K of the energy storage heterojunction prepared in Example 1, Example 2, Example 3, Example 4 of the present application and Comparative Example 1 under near-infrared light x Cs 0.32-x WO3powder to 20 mg·L -1 Piezophotocatalytic reaction 0~1 min degradation rate graph of BPA at different concentrations; Figure 34 K of the energy storage heterojunction prepared in Example 1, Example 2, Example 3, Example 4 of the present application and Comparative Example 1 under near-infrared light x Cs 0.32-x WO3powder to 20 mg·L -1 Piezophotocatalytic reaction 1~9 min degradation rate graph of BPA at different concentrations; Figure 35 Cycle degradation graph of BPA at 20 mg·L -1 BPA by the energy storage heterojunction prepared in Example 3 under near-infrared light.

[0020] Figure 36 K of Comparative Example 1 under near-infrared light x Cs 0.32-x WO3powder to 20 mg·L -1 Cycle degradation graph of BPA. DETAILED DESCRIPTION

[0021] Other advantages and benefits of the present application will become apparent to those skilled in the art upon consideration of the disclosure or can be learned by practice of the application. The present application can be realized and achieved by means other than as specifically described herein and various modifications and changes in detail can be made therein by those skilled in the art without departing from the spirit and scope of the application.

[0022] It should be noted that the process equipment or devices not specifically mentioned in the following examples are all conventional equipment or devices in the art.

[0023] It is to be understood that the terms "including", "comprising", "having" and their conjugates mean "including but not limited to", e.g. a process, method, object, or apparatus that comprises a list of steps or elements is not necessarily limited to those specifically listed and can include other steps or elements not expressly listed or inherent to such process, method, object, or apparatus. Further, unless otherwise specified, the steps of the methods described herein are not necessarily performed in the order indicated and non-dependent steps can be performed in any order or simultaneously, unless otherwise indicated or required by the context. Modifications of the described methods and other steps and elements can occur to one skilled in the art without departing from the scope of the application, which is defined by the appended claims.

[0024] Comparative Example 1 Step 1, 1.1222 mmol WCl6 powder, 0.3950 mmol CsNO3 powder and 0.1772 mmol KNO3 were dispersed into 54 mL anhydrous ethanol to obtain a yellow turbid solution; Step 2, the yellow turbid solution was heated and stirred at 50°C for 240 min, and mixed with 20 mL of a citric acid solution with a concentration of 0.36 mol / L to obtain a purple turbid precursor solution; Step 3, the purple turbid precursor solution was subjected to a solvothermal reaction at 200°C for 16 h, and after the reaction was completed, the product in the reaction solution was washed, separated and dried to obtain a precipitate.

[0025] Step 4, the precipitate was washed with deionized water and anhydrous ethanol for 3 times respectively, and the filter cake after washing was dried at 70°C for 12 h to obtain K x Cs 0.32-x WO3 powder.

[0026] Comparative Example 2 Step 1, 0.1 mol Bi(NO3)3·5H2O was added to 50 mL water, and 0.1 mmol NaBr was added while stirring to obtain a mixed solution.

[0027] Step 2, the mixed solution was stirred at room temperature for 60 min to form a uniform precursor solution.

[0028] Step 3, the precursor solution was subjected to a hydrothermal reaction at 160°C for 12 hours to obtain a precipitate.

[0029] Step 4, the precipitate was washed with deionized water and anhydrous ethanol for 3 times respectively, and the filter cake after washing was dried at 70°C for 12 h to obtain BiOBr powder.

[0030] Example 1 Step 1, 1.0 mmol K x Cs 0.32-xWO3powder and 2.3 mmol BiOBr were dispersed into 100 mL of quartz beaker containing 20 mL of ethanol, respectively, and ultrasonic treatment for 30 min to obtain a uniform suspension; Step 2, the obtained suspension was placed in XPA-3 photochemical reaction instrument, and 300 W mercury lamp ultraviolet light irradiation for 30 min under continuous magnetic stirring; Step 3, the BiOBr suspension was slowly poured into K x Cs 0.32-x WO3(KCWO) suspension, and the obtained mixed suspension was irradiated with ultraviolet light for 3 h under continuous magnetic stirring to obtain precipitated powder.

[0031] Step 4, the obtained precipitated powder was washed with deionized water and anhydrous ethanol for 3 times, respectively, and dried at 70℃ for 12 h to obtain S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction.

[0032] Example 2 Step 1, 1.0 mmol K x Cs 0.32-x WO3powder and 1.5 mmol BiOBr were dispersed into 100 mL of quartz beaker containing 20 mL of ethanol, respectively, and ultrasonic treatment for 30 min to obtain a uniform suspension; Step 2, the obtained suspension was placed in XPA-3 photochemical reaction instrument, and 300 W mercury lamp ultraviolet light irradiation for 30 min under continuous magnetic stirring; Step 3, the BiOBr suspension was slowly poured into K x Cs 0.32-x WO3(KCWO) suspension, and the obtained mixed suspension was irradiated with ultraviolet light for 3 h under continuous magnetic stirring to obtain precipitated powder.

[0033] Step 4, the obtained precipitated powder was washed with deionized water and anhydrous ethanol for 3 times, respectively, and dried at 70℃ for 12 h to obtain S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction.

[0034] Example 3 Step 1, 1.0 mmol K x Cs 0.32-x WO3powder and 1.0 mmol BiOBr were dispersed into 100 mL of quartz beaker containing 20 mL of ethanol, respectively, and ultrasonic treatment for 30 min to obtain a uniform suspension; Step 2, the obtained suspension was placed in XPA-3 photochemical reactor, and after 300 W mercury lamp ultraviolet irradiation for 30 min under continuous magnetic stirring; Step 3, the BiOBr suspension was slowly poured into the K x Cs 0.32-x WO3(KCWO) suspension, and the obtained mixed suspension was further ultraviolet irradiated under magnetic stirring for 3 h to obtain precipitated powder.

[0035] Step 4, the precipitated powder was washed with deionized water and anhydrous ethanol for 3 times respectively, and dried at 70℃ for 12 h to obtain S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction.

[0036] Example 4 Step 1, 1.0 mmol K x Cs 0.32-x WO3 powder and 0.66 mmol BiOBr were respectively dispersed into 100 mL quartz beaker containing 20 mL ethanol, and ultrasonic treatment was carried out for 30 min to obtain uniform suspension; Step 2, the obtained suspension was placed in XPA-3 photochemical reactor, and after 300 W mercury lamp ultraviolet irradiation for 30 min under continuous magnetic stirring; Step 3, the BiOBr suspension was slowly poured into the K x Cs 0.32-x WO3(KCWO) suspension, and the obtained mixed suspension was further ultraviolet irradiated under magnetic stirring for 3 h to obtain precipitated powder.

[0037] Step 4, the precipitated powder was washed with deionized water and anhydrous ethanol for 3 times respectively, and dried at 70℃ for 12 h to obtain S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction.

[0038] Example 5 Step 1, 1.0 mmol K x Cs 0.32-x WO3 powder and 0.11 mmol BiOBr were respectively dispersed into 100 mL quartz beaker containing 20 mL ethanol, and ultrasonic treatment was carried out for 30 min to obtain uniform suspension; Step 2, the obtained suspension was placed in XPA-3 photochemical reactor, and after 300 W mercury lamp ultraviolet irradiation for 30 min under continuous magnetic stirring; Step 3, the BiOBr suspension was slowly poured into the K x Cs 0.32-xThe obtained mixed suspension is irradiated with ultraviolet light for 3 h under continuous magnetic stirring to obtain precipitated powder.

[0039] Step 4, the obtained precipitated powder is washed with deionized water and anhydrous ethanol for 3 times respectively, and dried at 70°C for 12 h to obtain S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction.

[0040] Example 6 Step 1, 1.0 mmol K x Cs 0.32-x WO3 powder and 1.0 mmol BiOBr are respectively dispersed into 100 mL of quartz beaker containing 20 mL of ethanol, and ultrasonic treatment is performed for 30 min to obtain uniform suspension; Step 2, the obtained suspension is placed in XPA-3 photochemical reaction instrument, and 300 W mercury lamp ultraviolet light is irradiated for 30 min under continuous magnetic stirring; Step 3, the BiOBr suspension is slowly poured into the K x Cs 0.32-x WO3(KCWO) suspension, and the obtained mixed suspension is irradiated with ultraviolet light for 4 h under continuous magnetic stirring to obtain precipitated powder.

[0041] Step 4, the obtained precipitated powder is washed with deionized water and anhydrous ethanol for 3 times respectively, and dried at 70°C for 12 h to obtain S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction.

[0042] Example 7 Step 1, 1.0 mmol K x Cs 0.32-x WO3 powder and 1.0 mmol BiOBr are respectively dispersed into 100 mL of quartz beaker containing 20 mL of ethanol, and ultrasonic treatment is performed for 30 min to obtain uniform suspension; Step 2, the obtained suspension is placed in XPA-3 photochemical reaction instrument, and 300 W mercury lamp ultraviolet light is irradiated for 30 min under continuous magnetic stirring; Step 3, the BiOBr suspension is slowly poured into the K x Cs 0.32-x WO3(KCWO) suspension, and the obtained mixed suspension is irradiated with ultraviolet light for 5 h under continuous magnetic stirring to obtain precipitated powder.

[0043] Step 4, the obtained precipitated powder is washed with deionized water and anhydrous ethanol for 3 times respectively, and dried at 70°C for 12 h to obtain S-type BiOBr / Kx Cs 0.32-x WO3 energy storage heterojunction.

[0044] Example 8 Step 1, 1.0 mmol K x Cs 0.32-x WO3 powder and 1.0 mmol BiOBr were respectively dispersed into 100 mL of quartz beaker containing 20 mL of ethanol, and were ultrasonically treated for 30 min to obtain uniform suspensions; Step 2, the obtained suspensions were placed in an XPA-3 photochemical reaction instrument, and were irradiated with 300 W mercury lamp ultraviolet light for 30 min under continuous magnetic stirring; Step 3, the BiOBr suspension was slowly poured into the K x Cs 0.32-x WO3(KCWO) suspension, and the obtained mixed suspension was further irradiated with ultraviolet light for 6 h under magnetic stirring to obtain precipitated powder.

[0045] Step 4, the obtained precipitated powder was washed with deionized water and anhydrous ethanol for 3 times respectively, and was dried at 70°C for 12 h to obtain S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction.

[0046] Example 9 Step 1, 1.0 mmol K x Cs 0.32-x WO3 powder and 1.0 mmol BiOBr were respectively dispersed into 100 mL of quartz beaker containing 20 mL of ethanol, and were ultrasonically treated for 30 min to obtain uniform suspensions; Step 2, the obtained suspensions were placed in an XPA-3 photochemical reaction instrument, and were irradiated with 300 W mercury lamp ultraviolet light for 40 min under continuous magnetic stirring; Step 3, the BiOBr suspension was slowly poured into the K x Cs 0.32-x WO3(KCWO) suspension, and the obtained mixed suspension was further irradiated with ultraviolet light for 3 h under magnetic stirring to obtain precipitated powder.

[0047] Step 4, the obtained precipitated powder was washed with deionized water and anhydrous ethanol for 3 times respectively, and was dried at 70°C for 12 h to obtain S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction.

[0048] Example 10 Step 1, 1.0 mmol K x Cs 0.32-xWO3powder and 1.0 mmol BiOBr were dispersed into 100 mL of quartz beaker containing 20 mL of ethanol, respectively, and ultrasonic treatment for 30 min to obtain a uniform suspension; Step 2, the obtained suspension was placed in XPA-3 photochemical reaction instrument, and 300 W mercury lamp ultraviolet light irradiation for 50 min under continuous magnetic stirring; Step 3, the BiOBr suspension was slowly poured into K x Cs 0.32-x WO3(KCWO) suspension, and the obtained mixed suspension was ultraviolet irradiated for 3 h under continuous magnetic stirring to obtain precipitated powder.

[0049] Step 4, the obtained precipitated powder was washed with deionized water and anhydrous ethanol for 3 times, respectively, and dried at 70℃ for 12 h to obtain S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction.

[0050] Example 11 Step 1, 1.0 mmol K x Cs 0.32-x WO3powder and 1.0 mmol BiOBr were dispersed into 100 mL of quartz beaker containing 20 mL of ethanol, respectively, and ultrasonic treatment for 30 min to obtain a uniform suspension; Step 2, the obtained suspension was placed in XPA-3 photochemical reaction instrument, and 300 W mercury lamp ultraviolet light irradiation for 60 min under continuous magnetic stirring; Step 3, the BiOBr suspension was slowly poured into K x Cs 0.32-x WO3(KCWO) suspension, and the obtained mixed suspension was ultraviolet irradiated for 3 h under continuous magnetic stirring to obtain precipitated powder.

[0051] Step 4, the obtained precipitated powder was washed with deionized water and anhydrous ethanol for 3 times, respectively, and dried at 70℃ for 12 h to obtain S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction.

[0052] Example 12 Step 1, 1.0 mmol K x Cs 0.32-x WO3powder and 1.0 mmol BiOBr were dispersed into 100 mL of quartz beaker containing 20 mL of ethanol, respectively, and ultrasonic treatment for 30 min to obtain a uniform suspension; Step 2, the obtained suspension was placed in an XPA-3 photochemical reactor, and irradiated with 300 W mercury lamp ultraviolet light for 80 min under continuous magnetic stirring, respectively; Step 3, the BiOBr suspension was slowly poured into the K x Cs 0.32-x WO3(KCWO) suspension, and the obtained mixed suspension was further irradiated with ultraviolet light under magnetic stirring for 3 h to obtain a precipitated powder.

[0053] Step 4, the obtained precipitated powder was washed with deionized water and anhydrous ethanol for 3 times, respectively, and dried at 70℃ for 12 h to obtain S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction.

[0054] Piezoelectric photocatalytic experiment: the photocatalytic degradation performance of the sample was evaluated by the BPA photodegradation experiment with an initial concentration of 20 mg / L. The light degradation experiment was carried out on an XPA-7 photochemical reactor (Nanjing Xujing Machinery Factory) by using a 500W xenon lamp to simulate sunlight source (190 nm~2500 nm) and a 500W xenon lamp with filter to simulate near-infrared light (QFS2500+800 long wave pass filter, 800 nm~2500 nm). 50 mg of catalyst was dispersed in 50 mL of 20 mg / L BPA solution. During the light irradiation process, 5 mL of the suspension was taken out periodically and centrifuged, and then filtered through a 0.22 μm membrane. The absorbance value of the filtrate was tested, and the residual concentration A of the pollutant was determined by a UV spectrophotometer (SP-756P). The initial concentration was denoted as A0, and the degradation rate was calculated according to the formula The characteristic absorption wavelength of BPA is 270 nm; the characteristic absorption wavelength of TC is 358 nm; and the characteristic absorption wavelength of methylene blue (MB) is 666 nm.

[0055] Piezoelectric catalytic experiment: the degradation experiment was carried out on an XPA-7 photochemical reactor (Nanjing Xujing Machinery Factory). The specific operation was as follows: 50 mg of catalyst was dispersed in 20 mg / L of BPA. Under dark conditions, about 5 mL of solution was taken out every 1 min, and then filtered through a 0.22 μm membrane. The absorbance value of the filtrate was tested, and the absorbance at the maximum absorption wavelength was selected to represent the degradation efficiency of the sample on the target degradation substance.

[0056] The above conclusion and mechanism are described in detail as follows.

[0057] Figure 1 is the XRD pattern of the energy storage heterojunction prepared in Examples 1~5 of the present application. The diffraction peaks of the energy storage heterojunctions in each example at 13.8°, 23.4°, 27.2°, 27.7°, 33.8° and 36.6° are consistent with the K xCs 0.32-x The (100), (002), (102), (200), (112) and (202) characteristic diffraction peaks of WO3(JCPDS: 83-1334) coincide, and the diffraction peaks at 10.9°, 25.2°, 31.7°, 32.2° and 57.2° coincide with the (001), (101), (102), (110) and (212) characteristic diffraction peaks of tetragonal phase BiOBr(JCPDS: 78-0348), and the diffraction peak intensity of BiOBr is enhanced with the increase of the molar ratio of BiOBr.

[0058] Figure 2 The XRD data of the energy storage heterojunction prepared in Examples 1-5 of the present application are refined and simulated, and the Maud software is used to refine and simulate the XRD data by the Rietveld principle. It can be seen that the error factor R w is controlled below 15%, which proves that the energy storage heterojunction prepared exists tetragonal phase BiOBr crystal with space group P4(nmm) and hexagonal phase K x Cs 0.32-x WO3crystal, and the molar percentage of the two phases after compounding basically coincides with the molar ratio of the ingredients.

[0059] Figure 3 The Raman spectrum of the energy storage heterojunction prepared in Examples 1-5 of the present application is shown in the figure, and the peak values at 150-360 cm -1 and 500-850 cm -1 are respectively attributed to the bending mode and stretching mode of O-W-O, and the peak value at 850-980 cm -1 corresponds to the W=O stretching mode. The strong spectrum band at 105-125 cm -1 can be attributed to the internal Bi-Br stretching vibration mode of A 1g . The spectrum band at 150-170 cm -1 can be attributed to the internal Bi-Br stretching vibration mode of Eg, which proves that BiOBr and K x Cs 0.32- x WO3two phases.

[0060] Figure 4 The HRTEM image of the energy storage heterojunction prepared in Example 3 of the present application is shown in the figure, and the lattice spacing of 0.317 nm and 0.384 nm is attributed to the (200) and (002) crystal faces of K x Cs 0.32-x WO3, and the lattice spacing of 0.283 nm is attributed to the (102) crystal face of BiOBr, which also proves that BiOBr / K x Cs0.32-x WO3 energy storage heterojunction.

[0061] Figure 5 are XPS spectra of energy storage heterojunctions prepared in Example 4, Example 3, Example 2, Comparative Example 1 and Comparative Example 2, respectively, each of which is calibrated by C 1s orbital binding energy (284.8 eV). The full spectra clearly show the presence of Cs, O, W, Bi and Br elements in the energy storage heterojunctions.

[0062] Figure 6 are XPS spectra of O 1s of energy storage heterojunctions prepared in Example 4, Example 3, Example 2, Comparative Example 1 and Comparative Example 2, respectively. The binding energies at 531.34 eV, 531.14 eV and 530.40 eV in Example 4, Example 3 and Example 2 are attributed to Bi-O lattice oxygen; the binding energies at 534.66 eV, 533.34 eV, 533.56 eV and 533.20 eV in Example 4, Example 3, Example 2 and Comparative Example 1 are attributed to surface oxygen vacancies, and the binding energies at 533.10 eV, 532.22 eV, 532.24 eV and 531.40 eV are attributed to W-O bonded lattice oxygen. The oxygen vacancy contents in Example 4, Example 3, Example 2 and Comparative Example 1 are 10.59%, 19.13%, 8.20% and 34.70%, respectively.

[0063] Figure 7 are XPS spectra of W 4f of energy storage heterojunctions prepared in Example 4, Example 3, Example 2 and Comparative Example 1, respectively. BiOBr / K x Cs 0.32-x The W 4f orbit of the WO3 energy storage heterojunction can be fitted into two pairs of double peaks, which are attributed to W 5+ with lower binding energy and W 6+ with higher binding energy, respectively. In Example 4, the binding energies of W 6+ are located at 35.32 eV and 37.58 eV, and the binding energies of W 5+ are located at 34.28 eV and 36.86 eV; in Example 3, the binding energies of W 6+ are located at 35.48 eV and 37.78 eV, and the binding energies of W 5+ are located at 34.20 eV and 36.58 eV; in Example 2, the binding energies of W 6+ are located at 35.68 eV and 37.90 eV, and the binding energies of W 5+ are located at 34.48 eV and 37.08 eV; in Comparative Example 1, the binding energies of W 6+ are located at 35.67 eV and 38.58 eV, and the binding energies of W 5+The binding energies are located at 33.88 eV and 37.82 eV. It is thus confirmed that there are still mixed valence W ions in the energy storage heterojunctions of Example 4, Example 3, Example 2 and Comparative Example 1. 5+ / W 6+ The percentage contents are 69.12% / 30.88%, 58.76% / 41.14%, 88.64% / 14.36% and 42.05% / 57.95%.

[0064] Figure 8 The binding energies of 725.54 eV and 739.48 eV in Example 4; the binding energies of 725.30 eV and 739.26 eV in Example 3; the binding energies of 724.02 eV and 737.86 eV in Example 2 and the binding energies of 724.68 eV and 738.56 eV in Comparative Example 1 in the XPS spectra of Cs 3d of the energy storage heterojunctions prepared in Example 4, Example 3, Example 2 and Comparative Example 1 correspond to the 3d signals of Cs + .

[0065] Figure 9 The XPS spectra of Bi 4f of the energy storage heterojunctions prepared in Example 4, Example 3, Example 2 and Comparative Example 2 show two strong peaks, which are respectively attributed to Bi 3+ 4f 7 / 2 and Bi 3+ 4f 5 / 2 After fitting, they are divided into four peaks. In Example 4, the binding energies of 166.46 eV and 161.16 eV belong to Bi 3+ , and the low binding energies of 166.16 eV and 160.46 eV belong to the low-charge Bi ions (Bi +(3-x) ) in the energy storage heterojunction; in Example 3, the binding energies of 166.46 eV and 160.96 eV belong to Bi 3+ , and the low binding energies of 165.56 eV and 159.76 eV belong to Bi +(3-x) ; in Example 2, the binding energies of 166.46 eV and 161.16 eV belong to Bi 3+ , and the low binding energies of 166.06 eV and 160.76 eV belong to Bi +(3-x) ; in Comparative Example 2, the binding energies of 167.16 eV and 161.76 eV belong to Bi 3+ , and the binding energies of 166.56 eV and 161.06 eV belong to Bi +(3-x) . In Example 4, Example 3, Example 2 and Comparative Example 2, the binding energies of Bi 3+ / Bi +(3-x)The percentage content is 67.73% / 32.27%, 64.92% / 35.08%, 59.53% / 40.47% and 57.83% / 42.17%. Because Bi +(3-x) Substituted Bi in the BiOBr crystal lattice 3+ , a hole is bound around Bi +(3-x) , indicating the existence of electrons and holes in the BiOBr crystal.

[0066] Figure 10 The XPS spectrum of the energy storage heterojunction prepared by Example 4, Example 3, Example 2 and Comparative Example 2 is Br 3d. In Example 4, Example 3, Example 2 and Comparative Example 2, there are two strong peaks, the binding energy at 69.22 eV, 69.02 eV, 69.44 eV and 69.46 eV belongs to Br 3d 7 / 2 , the binding energy at 68.18 eV, 68.08 eV, 68.36 eV and 66.52 eV belongs to Br 3d 5 / 2 .

[0067] The above results show that after the formation of the S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction, the binding energy of Br 3d and Bi 4f decreases, while the binding energy of W 4f and Cs 3d increases, indicating that electrons are transferred from K x Cs 0.32-x WO3 to BiOBr, which indicates that the interface of the BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction forms an interfacial polarization electric field.

[0068] When the BiOBr suspension and the KCWO suspension are respectively irradiated with ultraviolet light under magnetic stirring, the polar BiOBr crystal and the K x Cs 0.32-x WO3 piezoelectric crystal deforms to induce a piezoelectric polarization electric field, and at the same time, ultraviolet light excitation forms photo-generated electrons and holes. Under the action of the deformation piezoelectric polarization electric field, the stored electrons, holes and photo-generated electrons, holes migrate to the BiOBr crystal and the K x Cs 0.32-x WO3 crystal surface to recombine, and the remaining charges make the BiOBr crystal and the K x Cs 0.32-x WO3 crystal surface carry charges. The BiOBr suspension is slowly poured into the K x Cs 0.32-x WO3 suspension, and the BiOBr and K x Cs 0.32-x WO3 are attracted by the surface charges to form a BiOBr / K xCs 0.32-x WO3 heterojunction, BiOBr interface side band negative, K x Cs 0.32-x WO3 interface side band positive, BiOBr and Cs 0.32 The work function of WO3 is 5.90 eV and 3.59 eV respectively. Due to BiOBr and K x Cs 0.32-x The work function of WO3 exists difference, under the action of work function difference, electron will tend to flow from K x Cs 0.32-x The E of WO3 f KCWO The E of BiOBr f BOB Make electron accumulate in BiOBr interface, reduce the E of BiOBr fBOB , relatively, such electron flow trend will make K x Cs 0.32-x The E of WO3 f KCWO Lift, until the Fermi level of both reaches balance, so that BiOBr and K x Cs 0.32-x The band of BiOBr at the contact interface of WO3 occurs downward bending, K x Cs 0.32-x The band of WO3 occurs upward bending, BiOBr side of interface band negative, K x Cs 0.32-x WO3 side band positive, so that BiOBr and K x Cs 0.32-x Interface electric field E is formed at the interface of WO3, direction from K x Cs 0.32-x The interface of WO3 points to BiOBr interface, formed S type BiOBr / K x Cs 0.32-x The heterojunction of WO3, interface forms space charge region, with Figures 5-10 The binding energy of Br 3d and Bi 4f of is reduced, while the binding energy of W 4f and Cs 3d is increased, electron flows from K x Cs 0.32-x The result of WO3 flows to BiOBr is consistent.

[0069] BiOBr / K x Cs 0.32-x After the S type heterojunction of WO3 is formed, continue to irradiate under stirring shear stress for 3 h, photoexcitation and piezoelectric effect make BiOBr and K x Cs 0.32-xThe photo-generated carriers and induced piezoelectric charges of the WO3 crystal are stored in the valence band of the BiOBr crystal under the action of the deformation piezoelectric polarization electric field of the crystal. Under the action of the interface S-type electric field, the photo-generated electrons and induced piezoelectric negative charges of the BiOBr crystal drift to the K x Cs 0.32- x The photo-generated carriers and induced piezoelectric charges of the WO3 crystal are stored in the valence band of the BiOBr crystal under the action of the deformation piezoelectric polarization electric field of the crystal. Under the action of the interface S-type electric field, the photo-generated electrons and induced piezoelectric negative charges of the BiOBr crystal drift to the K x Cs 0.32-x The photo-generated carriers and induced piezoelectric charges of the WO3 crystal are stored in the valence band of the BiOBr crystal under the action of the deformation piezoelectric polarization electric field of the crystal. Under the action of the interface S-type electric field, the photo-generated electrons and induced piezoelectric negative charges of the BiOBr crystal drift to the K x Cs 0.32-x The photo-generated carriers and induced piezoelectric charges of the WO3 crystal are stored in the valence band of the BiOBr crystal under the action of the deformation piezoelectric polarization electric field of the crystal. Under the action of the interface S-type electric field, the photo-generated electrons and induced piezoelectric negative charges of the BiOBr crystal drift to the K x Cs 0.32-x The photo-generated carriers and induced piezoelectric charges of the WO3 crystal are stored in the valence band of the BiOBr crystal under the action of the deformation piezoelectric polarization electric field of the crystal. Under the action of the interface S-type electric field, the photo-generated electrons and induced piezoelectric negative charges of the BiOBr crystal drift to the K x Cs 0.32-x The photo-generated carriers and induced piezoelectric charges of the WO3 crystal are stored in the valence band of the BiOBr crystal under the action of the deformation piezoelectric polarization electric field of the crystal. Under the action of the interface S-type electric field, the photo-generated electrons and induced piezoelectric negative charges of the BiOBr crystal drift to the K x Cs 0.32-x The photo-generated carriers and induced piezoelectric charges of the WO3 crystal are stored in the valence band of the BiOBr crystal under the action of the deformation piezoelectric polarization electric field of the crystal. Under the action of the interface S-type electric field, the photo-generated electrons and induced piezoelectric negative charges of the BiOBr crystal drift to the K x Cs 0.32-x The photo-generated carriers and induced piezoelectric charges of the WO3 crystal are stored in the valence band of the BiOBr crystal under the action of the deformation piezoelectric polarization electric field of the crystal. Under the action of the interface S-type electric field, the photo-generated electrons and induced piezoelectric negative charges of the BiOBr crystal drift to the K x Cs 0.32-x The photo-generated carriers and induced piezoelectric charges of the WO3 crystal are stored in the valence band of the BiOBr crystal under the action of the deformation piezoelectric polarization electric field of the crystal. Under the action of the interface S-type electric field, the photo-generated electrons and induced piezoelectric negative charges of the BiOBr crystal drift to the K x Cs 0.32-x The photo-generated carriers and induced piezoelectric charges of the WO3 crystal are stored in the valence band of the BiOBr crystal under the action of the deformation piezoelectric polarization electric field of the crystal. Under the action of the interface S-type electric field, the photo-generated electrons and induced piezoelectric negative charges of the BiOBr crystal drift to the K x Cs 0.32-x The photo-generated carriers and induced piezoelectric charges of the WO3 crystal are stored in the valence band of the BiOBr crystal under the action of the deformation piezoelectric polarization electric field of the crystal. Under the action of the interface S-type electric field, the photo-generated electrons and induced piezoelectric negative charges of the BiOBr crystal drift to the K x Cs 0.32-x The photo-generated carriers and induced piezoelectric charges of the WO3 crystal are stored in the valence band of the BiOBr crystal under the action of the deformation piezoelectric polarization electric field of the crystal. Under the action of the interface S-type electric field, the photo-generated electrons and induced piezoelectric negative charges of the BiOBr crystal drift to the K x Cs 0.32-x The photo-generated carriers and induced piezoelectric charges of the WO3 crystal are stored in the valence band of the BiOBr crystal under the action of the deformation piezoelectric polarization electric field of the crystal. Under the action of the interface S-type electric field, the photo-generated electrons and induced piezoelectric negative charges of the BiOBr crystal drift to the K Figures 5-10 The XPS proves that the BiOBr / K x Cs 0.32-x The oxygen vacancies, Bi 3+ / Bi +(3-x) and W 5+ / W6+ The study verified that an S-type BiOBr / K-type electron- and hole-storing material can be formed by electrostatic adsorption using a synergistic method of photoexcitation and piezoelectric effect. x Cs 0.32-x WO3 energy storage heterojunction.

[0070] Figure 11 The UV-vis diffuse reflectance spectra prepared in Examples 4, 3, 2, Comparative Example 1, and Comparative Example 2 of this invention show that the energy storage heterojunction exhibits obvious light absorption peaks in the ultraviolet regions of 290 nm and 340 nm and in the visible and near-infrared regions of 500–2000 nm. It also possesses light absorption capability across the entire spectral range of 200–2000 nm. The light absorption capability of the energy storage heterojunction is between that of BiOBr and K. x Cs 0.32-x Between WO3.

[0071] Figure 12 , Figure 13 The valence band spectrum and band gap width plots of Comparative Examples 1 and 2 are shown below, along with BiOBr and K. x Cs 0.32-x The VB values ​​for WO3 are 2.25 eV and 2.09 eV, respectively. Based on the Kubelka-Munk conversion calculation diagram, BOB and K... x Cs 0.32-x The band gap energies of WO3 are approximately 2.90 eV and 2.84 eV, respectively, according to the formula: BiOBr and K x Cs 0.32-x The CB values ​​for WO3 are -0.65 eV and -0.75 eV, respectively.

[0072] Figure 14 The images shown are piezoelectric microscopy (PFM) images and dark-light transient pressure-current diagrams for Examples 3, 4, and Comparative Example 1, respectively. (a), (b), and (c) correspond to Examples 3, 4, and Comparative Example 1, respectively, and S-type BiOBr / K can be observed. x Cs 0.32-x Phase and amplitude morphology of WO3 energy storage heterojunction ( Figure 14 In (a1)~(c1) and (a2)~(c2), when a DC voltage from -10V to +10V is applied to the energy storage heterojunction, a phase angle shift of nearly 180° occurs. This phenomenon indicates that the S-type BiOBr / K x Cs 0.32- x The WO3 energy storage heterojunction exhibits strain electric field hysteresis. Its amplitude-voltage curve displays a typical "butterfly ring" pattern. Figure 14In (a3)~(c3), the appearance of the "butterfly ring" is considered to be caused by the combined effect of the piezoelectric field and the motion of the dipole. This not only confirms that the energy storage heterojunction has piezoelectric properties, but also indicates that there is a polarized electric field inside the energy storage heterojunction. The piezoelectric coefficients (d) of Examples 3, 4 and Comparative Example 1 were calculated by fitting. 33 The values ​​are 79.92 nm·V. -1 56.27 nm·V -1 and 2.11 nm·V -1 Prove that S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunctions have better piezoelectric properties, and S-type BiOBr / K x Cs 0.32-x The large polarization electric field of the WO3 energy storage heterojunction is a fundamental guarantee for the simultaneous storage of free electrons and holes.

[0073] Under intermittent stress in a magnetic stirrer under dark conditions, turning off the stirrer results in an increased positive current value, while turning it on results in a reverse current value with fluctuating amplitude. Figure 14 The changes in transient piezoelectric current values ​​under magnetic stirring and mechanical stress in dark conditions (a4~c4) further illustrate the S-type BiOBr / K x Cs 0.32-x The WO3 energy storage heterojunction has a polarized electric field, and changes in mechanical stress can drive the release of stored electrons and holes.

[0074] Figures 15-20 The energy storage heterojunctions prepared in Examples 1-5 of this invention and Comparative Example 1K x Cs 0.32-x The MB decolorization experiment diagram of WO3 was used to calculate the energy storage heterojunctions prepared in Examples 1-5 and Comparative Example 1 K. x Cs 0.32-x The electron concentration of WO3 is 52.51 µmol·g. -1 57.03 µmol·g -1 61.01 µmol·g -1 133.12 µmol·g -1 152.63 µmol·g -1 and 328.60 µmol·g -1 .

[0075] Figure 21 The concentration map of the heterogeneous hole for energy storage prepared in Example 3 of this invention. (The data was obtained using TEMPO-h...) + The h stored in Example 3 was obtained through testing and quantum spin number calculation. +The concentration was 29.81 µmol·g. -1 Explanation of S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunctions store electrons and holes.

[0076] Figure 22 This is a piezoelectric catalytic performance graph of the energy storage heterojunction prepared in the embodiments of the present invention under dark conditions. During the reaction time of 0-1 min under dark conditions, the energy storage heterojunctions prepared in Examples 3, 4, and 5, as well as the materials in Comparative Examples 1 and 2, showed piezoelectric catalytic performance at 20 mg·L⁻¹. -1 The piezoelectric degradation rates of BPA were 71.70%, 60.32%, 61.65%, 70.36%, and 61.40%, respectively. Figure 23 The corresponding degradation rates were 1.27121 min. -1 0.97128 min -1 0.94019min -1 and 1.22010 min -1 and 0.95191 min -1 During the 0-1 min period, the S-type BiOBr / K prepared in Example 3... x Cs 0.32-x The piezoelectric catalytic rate of WO3 energy storage heterojunction is K. x Cs 0.32-x The WO3 and BiOBr were 1.04 and 1.33 times higher, respectively. After reacting in the dark for 1–7 min, the energy storage heterojunctions prepared in Examples 3, 4, and 5, as well as the materials in Comparative Examples 1 and 2, were compared with 20 mg·L⁻¹. -1 The degradation rates of BPA were 12.7%, 18.09%, 15.92%, and 5.47% and 1.62%, respectively. Figure 24 The corresponding degradation rates were 0.07669 min. -1 0.06758 min -1 0.06871 min -1 and 0.00916 min -1 and 0.00644 min -1 During the 1-7 min period, the S-type BiOBr / K prepared in Example 3 x Cs 0.32-x The piezoelectric catalytic rate of WO3 energy storage heterojunction is K x Cs 0.32-xThe degradation rate was 8.37 times that of WO3 and 11.09 times that of BiOBr. The 7-minute degradation reaction was divided into two stages: 0-1 min was the energy storage piezoelectric catalytic stage, and 1-7 min was the piezoelectric catalytic stage. The degradation rate and degradation speed of the energy storage heterojunctions in each embodiment during the 1-7 min piezoelectric catalytic stage were higher than those of the materials in Comparative Example 1 and Comparative Example 2.

[0077] After reacting in the dark for 7 min, the energy storage heterojunctions prepared in Examples 3, 4, and 5, as well as the materials in Comparative Examples 1 and 2, were compared with 20 mg·L⁻¹. -1 The total degradation rates of BPA were 81.53%, 78.41%, 77.57%, 75.83%, and 63.02%, respectively. Figure 25 The energy storage heterojunction prepared in Example 3 was tested under dark conditions at 20 mg·L⁻¹ -1 In the degradation cycle experiment of BPA, the degradation efficiency remained at 66.66% after ten cycles. Figure 26 K is for Comparative Example 1 x Cs 0.32-x WO3 powder under dark conditions at 20 mg·L -1 In the degradation cycle experiment of BPA, the degradation efficiency remained at only 53.21% after ten cycles. In Example 3, the degradation ability was significantly improved after cycling under dark conditions.

[0078] Figure 27 Simulated sunlight exposure for 0–1 min, Examples 1, 3, 5 and Comparative Example 1 compared to 20 mg·L⁻¹. -1 The degradation rates of BPA at different concentrations were 66.78%, 72.78%, 70.06%, and 68.76%, respectively. Figure 28 The corresponding degradation rate was 1.20807 min. -1 1.30126 min -1 1.10215min -1 and 1.16351min -1 Simulating the rapid release of high-concentration electron-hole cavities attributed to storage through rapid degradation under sunlight (0-1 min), the S-type BiOBr / K prepared in Example 3... x Cs 0.32-x The piezoelectric catalytic rate of WO3 energy storage heterojunction is K. x Cs 0.32-x 1.12 times that of WO3. Figure 27 After simulating sunlight exposure for 1–9 min, Examples 1, 3, 5, and Comparative Example 1 were compared with 20 mg·L⁻¹. -1 The degradation rates of BPA at different concentrations were 12.37%, 15.66%, 7.38%, and 7.63%, respectively. Figure 29The corresponding degradation rate is 0.02651 min -1 , 0.11497 min -1 , 0.04820 min -1 and 0.03498 min -1 . The slow degradation of reactions 1-9 min under simulated sunlight is attributed to S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction strain formed piezoelectric charge and photo-generated electron-hole pairs BPA degradation, prepared in Example 3 S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction piezoelectric photocatalytic rate is K x Cs 0.32-x WO3 3.30 times.

[0079] After 9 min of simulated sunlight irradiation, the total degradation rate of 20 mg·L -1 concentration of BPA by Example 1, Example 3, Example 5 and Comparative Example 1 was 79.15%, 88.44%, 77.44% and 76.39%, respectively. Figure 30 The degradation cycle experiment of 20 mg·L -1 BPA by Example 3 under simulated sunlight, the degradation efficiency still maintained at 61.56%, Figure 31 The degradation cycle experiment of 20 mg·L x BPA by K 0.32-x Cs -1 WO3 powder under simulated sunlight, the degradation efficiency after three cycles was only 38.99%. Compared with pure K x Cs 0.32-x WO3, S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction has been significantly improved in the stability of the cyclic degradation of BPA under simulated sunlight.

[0080] Figure 32 Under near-infrared light irradiation for 0-1 min, the degradation rate of 20 mg·L x concentration of BPA by the energy storage heterojunction prepared in Example 1, Example 2, Example 3, Example 4 and K 0.32-x Cs -1 WO3 powder was 52.38%, 64.58%, 71.15%, 69.32% and 60.80%, respectively. Figure 33 The corresponding degradation rate is 0.80651 min -1 , 1.18122 min -1 , 1.24295 min-1 , 1.03881 min -1 and 0.93902 min -1 , the rapid degradation under near-infrared light within 0~1 min is attributed to the rapid release of stored high-concentration electron holes, and the S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction energy storage piezoelectric catalytic rate is K x Cs 0.32-x 1.32 times that of Cs Figure 32 After 1~9 min of near-infrared light irradiation, the K x Cs 0.32-x WO3 powder to 20 mg·L -1 The degradation rates of BPA with a concentration of 20 mg·L Figure 34 The corresponding degradation rates are 0.08923 min -1 , 0.04711 min -1 , 0.03316 min -1 , 0.06005 min -1 and 0.02902 min -1 . The slow degradation under near-infrared light within 1~9 min is attributed to the degradation of BPA by the piezoelectric charge and photoelectron hole pairs of the S-type BiOBr / K x Cs 0.32-x WO3 energy storage heterojunction. x Cs 0.32-x The piezoelectric photocatalytic rate of the energy storage heterojunction of Example 3 is K x Cs 0.32- x 1.14 times that of Cs

[0081] After 9 min of near-infrared light irradiation, the K x Cs 0.32-x WO3 powder to 20 mg·L -1 The total degradation rates of BPA with a concentration of 20 mg·L Figure 35 The degradation cycle experiment of BPA with a concentration of 20 mg·L -1 The degradation efficiency still maintains at 61.93%, Figure 36 The K xCs 0.32-x WO3 powder under near-infrared light to 20 mg·L -1 The degradation efficiency of BPA after three cycles was only 44.47%. Compared with pure K x Cs 0.32-x WO3, S-type BiOBr / K x Cs 0.32-x The cycle degradation stability of WO3 energy storage heterojunction to BPA under near-infrared light irradiation was obviously improved.

[0082] The above is only one embodiment of the present application, not all or only one embodiment, any equivalent transformation of the technical solution of the present application by a person skilled in the art by reading the specification of the present application is covered by the claims of the present application.

Claims

1. A method for preparing S-shaped bismuth oxybromide / cesium tungsten bronze energy storage heterojunction, characterized in that, The method comprises the following steps: Step 1, K x Cs 0.32-x WO3and BiOBr were dispersed into ethanol to obtain K x Cs 0.32-x WO3and BiOBr suspensions; Step 2, K x Cs 0.32-x The WO3 suspension and the BiOBr suspension were irradiated with ultraviolet light under stirring, respectively; Step 3, pour the BiOBr suspension irradiated by ultraviolet light into the K x Cs 0.32-x WO3 suspension, and the obtained mixed suspension is irradiated by ultraviolet light under stirring to obtain precipitated powders; Step 4, the obtained precipitated powder is washed and dried to obtain S-type BiOBr / cesium tungsten bronze energy storage heterojunction.

2. The method of claim 1, wherein Bi OBr and K x Cs 0.32-x WO3 in a molar ratio of 7:3 to 1 :

9.

3. The preparation method of the S-type bismuth oxybromide / cesium tungsten bronze energy storage heterojunction according to claim 1, characterized in that, In step 2, the ultraviolet light irradiation time is 30-60 min, and in step 3, the ultraviolet light irradiation time is 3-6 h.

4. The preparation method of the S-type bismuth oxybromide / cesium tungsten bronze energy storage heterojunction according to claim 1, characterized in that, The K x Cs 0.32-x The WO3 is prepared by dispersing WCl6 powder, CsNO3 powder and KNO3 into anhydrous ethanol, heating, adding a citric acid solution to mix, obtaining a purple turbid precursor solution; the purple turbid precursor solution is subjected to a solvothermal reaction, and the obtained product is washed and dried to obtain K x Cs 0.32-x WO3 powder.

5. The method for preparing the S-type bismuth oxybromide / cesium tungsten bronze energy storage heterojunction according to claim 1, characterized in that, The preparation method of the BiOBr is as follows: Bi(NO3)3.5H2O is added to water, and NaBr is added while stirring to obtain a mixed solution; the mixed solution is stirred at room temperature to form a uniform precursor solution; the precursor solution is subjected to hydrothermal reaction to obtain a precipitate; and the precipitate is washed and dried to obtain BiOBr powder.

6. The S-type BiOBr / cesium tungsten bronze energy storage heterojunction obtained by the preparation method of any one of claims 1-5.

7. The S-shaped bismuth oxybromide / cesium tungsten bronzes energy storage heterojunction of claim 6, wherein, The S-type bismuth oxybromide / cesium tungsten bronze energy storage heterojunction, the cesium tungsten bronze crystal is a hexagonal phase K of space group P63 / mcm (193) x Cs 0.32-x WO3 crystal, bismuth oxybromide is a tetragonal phase BiOBr of space group P4 (nmm).

8. The S-shaped bismuth oxybromide / cesium tungsten bronze energy storage heterojunction of claim 6, wherein, The S-type bismuth oxybromide / cesium tungsten bronze energy storage heterojunction piezoelectric coefficient d 33 is 56.27~79.92 nm·V -1 .

9. The application of the S-type BiOBr / cesium tungsten bronze energy storage heterojunction of claim 6 in degrading organic pollutants under dark conditions.

10. The application of the S-type BiOBr / cesium tungsten bronze energy storage heterojunction of claim 6 in degrading organic pollutants under sunlight or near-infrared light.

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