BiO2-x energy storage catalyst as well as preparation method and application thereof

Abstract

The invention provides a BiO2-x energy storage catalyst and a preparation method and application thereof, the preparation method comprises the following steps: step 1, adding NaBiO3. 2H2O powder into a NaOH solution, and stirring to obtain a sodium bismuthate alkali solution; wherein the molar ratio of the NaBiO3. 2H2O to the NaOH is (0.045 to 0.18) to (2 to 4); step 2, dropwise adding the sodium bismuthate alkali solution into water, and stirring to obtain a reaction precursor solution; and 3, carrying out a hydrothermal reaction on the reaction precursor solution at 160-180 DEG C, and washing and drying the obtained reaction product to obtain the BiO2-x energy storage catalyst. The BiO2-x catalyst obtained by the preparation method has a piezoelectric property, and has a good broad-spectrum cyclic degradation effect on antibiotics, organic matters and dyes under a dark condition.

Description

Technical Field

[0001] The present invention belongs to the technical field of piezoelectric energy storage catalytic material preparation, specifically a BiO 2-x Energy storage catalyst and preparation method and application thereof. Background Art

[0002] At present, the discharge of industrial wastewater of antibiotics and synthetic dyes poses a serious threat to the environment. The continued presence of tetracycline in the environment not only contributes to the development of antibiotic-resistant bacteria, but also leads to the accumulation of biological toxicity, which has a subtle impact on the ecosystem and humans. Photocatalysis has great potential in solving the energy crisis and alleviating environmental pollution. Photocatalytic technology has attracted the attention and research of many researchers due to its advantages of environmental protection, high degradation efficiency and stable performance. However, the diffuse and regional characteristics of sunlight have limited the application of photocatalytic technology. Traditional photocatalytic technology cannot purify industrial wastewater of antibiotics and synthetic dyes under dark conditions. Therefore, piezoelectric energy storage catalytic materials with catalytic activity under dark conditions are a potential method to achieve effective degradation of industrial wastewater with low light transmittance.

[0003] BiO 2-x It is a non-toxic, structurally stable, and easy-to-synthesize bismuth-based semiconductor in which the uniformly dispersed Bi-6s orbital facilitates carrier migration and narrows the band gap. As a layered material with a narrow band gap (<2eV), it has excellent light absorption in the UV-visible-near infrared range and even in the infrared, making it one of the most attractive photocatalysts for the degradation of organic environmental pollutants in the full spectrum. However, there is currently no BiO 2-x Application report of catalyst in degradation of organic environmental pollutants under dark conditions. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a BiO 2-x Energy storage catalyst and preparation method and application thereof, BiO obtained by the preparation method 2-x The catalyst has piezoelectric properties and has good broad-spectrum cyclic degradation effects on antibiotics, organic matter and dyes under dark conditions.

[0005] The present invention is achieved through the following technical solutions: A BiO 2-x The preparation method of the energy storage catalyst comprises the following steps: Step 1: NaBiO 3 ·2H 2 O powder is added to the NaOH solution and stirred to obtain a sodium bismuthate alkaline solution; wherein NaBiO 3 ·2H 2The molar ratio of O to NaOH is: (0.045-0.18): (2-4); Step 2, adding the sodium bismuthate alkaline solution dropwise into water and stirring to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to a hydrothermal reaction at 160°C to 180°C, and the obtained reaction product is washed and dried to obtain BiO 2-x Energy storage catalyst.

[0006] Preferably, in step 1, the concentration of the NaOH solution is 2 mol / L to 4 mol / L.

[0007] Preferably, in step 2, the stirring time is 20 min to 120 min.

[0008] Preferably, in step 3, the hydrothermal reaction time is 30 min to 120 min.

[0009] Preferably, in step 3, washing is specifically: first centrifugally washing with deionized water until the pH of the obtained supernatant is 6.5-7, and then washing with anhydrous ethanol for multiple times.

[0010] Preferably, in step 3, drying is specifically: vacuum drying at 65°C to 75°C.

[0011] The present invention also provides a BiO obtained by the preparation method as described above. 2-x Energy storage catalyst, the BiO 2-x The energy storage catalyst is a cubic phase with a space point group of Fm-3m, BiO 2-x Energy storage catalysts store electrons and holes.

[0012] The present invention provides the BiO 2-x Application of energy storage catalysts in catalytic degradation of organic pollutants under dark conditions.

[0013] Preferably, the organic pollutant is an antibiotic or a dye.

[0014] The present invention also provides the BiO 2-x Application of energy storage catalysts in catalytic degradation of organic pollutants.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention BiO 2-x Preparation method of energy storage catalyst, NaBiO 3 ·2H 2 O powder is added to the NaOH solution, and only BiO 3 - and Na +, sodium bismuthate cannot be further hydrolyzed, and the sodium bismuthate alkaline solution is added drop by drop into the water. 3 - With H + Rapid binding, uniform generation of HBiO of the same size in solution 3 ·BiO 3 - The uniform particles are partially Bi during the hydrothermal reaction. 5+ Restore Bi 3+ , bind a hole in Bi 3+ Around, while escaping to form O 2 , causing oxygen deficiency inside the crystal (HBiO 3 ·BiO 3 +H 2 O→2BiO 2-x +O 2 ↑+H + ), the excess electrons formed by oxygen vacancies form BiO 2-x Nanocrystals, nanocrystals dissolve and crystallize in a hydrothermal high temperature environment to grow into tetragonal nanosheets and nanorod crystals. The short hydrothermal dissolution crystallization process of 30min~120min makes it impossible to eliminate the oxygen vacancies in the crystals, and the tetragonal nanosheets and nanorod crystals still have oxygen vacancies and Bi 3+ / Bi 5+ In order to balance the total charge of the crystal, tetragonal nanosheets and nanorods BiO 2-x Crystal lattice displacement generates piezoelectric polarization electric field. The crystal morphology of tetragonal nanosheets and nanorods is conducive to the release of piezoelectric charge. 3+ / Bi 5+ The existence of polarization electric field inside the crystal leads to BiO 2-x The energy storage catalyst stores a large number of electrons and holes at the same time. 2-x The strain caused by mechanical stress perturbation leads to the enhancement of its crystal piezoelectric polarization electric field, and the stored holes and vacancies are quickly released under dark conditions for catalytic reaction. At the same time, the mechanical stress perturbation strain makes BiO 2-x The energy storage catalyst generates piezoelectric charge, which is further released to continuously degrade organic pollutants.

[0016] The BiO 2-x Energy storage catalysts, due to the presence of oxygen vacancies and Bi in the crystal 3+ / Bi 5+ , making tetragonal nanosheets and nanorods BiO 2-x Crystal lattice displacement generates piezoelectric polarization electric field, tetragonal nanosheets and nanorods BiO under dark conditions 2-xThe release of stored charges and the formed piezoelectric charges have high degradation efficiency for antibiotics such as tetracycline and ciprofloxacin, organic substances such as bisphenol A, and dyes such as methylene blue and methylene orange, and have good cycle stability under dark conditions. 2-x Energy storage catalysts have good application prospects in the method of purifying water pollution under dark conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the examples of the present invention or the prior art, the drawings required for use in the examples or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are some examples of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 1 is the XRD diagram of the catalysts prepared in Example 1, Example 2 and Example 5 of the present invention.

[0019] Figure 2 3 is the Raman graph of the catalysts prepared in Examples 1, 2 and 5 of the present invention.

[0020] Figure 3 is a SEM image of the catalyst prepared in Example 1 of the present invention.

[0021] Figure 4 is the HRTEM image of the catalyst prepared in Example 1 of the present invention.

[0022] Figure 5 This is the absorbance curve of the catalyst prepared in Example 1 of the present invention to 20 mg / L methylene blue under dark conditions.

[0023] Figure 6 The catalyst prepared in Example 1 of the present invention is + Electron paramagnetic resonance spectrum.

[0024] Figure 7 It is the PFM phase change diagram of the catalyst prepared in Example 1 of the present invention.

[0025] Figure 8 It is a graph showing the PFM amplitude variation of the catalyst prepared in Example 1 of the present invention.

[0026] Fig. 9 It is the current diagram of the catalyst prepared in Example 1 of the present invention under dark conditions.

[0027] Fig.10 The degradation performance of the catalysts prepared in Examples 1, 2 and 5 of the present invention on 20 mg / L tetracycline under dark conditions is shown.

[0028] Fig.11 It is the removal rate of 40 mg / L tetracycline TOC by the catalysts prepared in Examples 1, 2 and 5 of the present invention under dark conditions.

[0029] Fig.12 It is the mass spectrum and mass-to-charge ratios of different peak positions of the catalyst prepared in Example 1 of the present invention degrading 20 mg / L tetracycline for 10 min under dark conditions.

[0030] Fig.13 It is the mass spectrum and mass-to-charge ratios of different peak positions of the catalyst prepared in Example 1 of the present invention degrading 20 mg / L tetracycline for 50 min under dark conditions.

[0031] Fig.14 The degradation performance of the catalysts prepared in Examples 1, 2 and 5 of the present invention on bisphenol A and ciprofloxacin under dark conditions.

[0032] Fig.15 This is an absorbance graph of the catalyst prepared in Example 1 of the present invention for a mixed solution of 20 mg / L tetracycline, 20 mg / L bisphenol A, 10 mg / L methylene blue, 10 mg / L methylene orange, and 10 mg / L ciprofloxacin under dark conditions.

[0033] Fig.16 1 is a graph showing the TOC removal rate of the catalyst prepared in Example 1 of the present invention for a mixed solution of 20 mg / L tetracycline, 20 mg / L bisphenol A, 10 mg / L methylene blue, 10 mg / L methylene orange, and 10 mg / L ciprofloxacin under dark conditions.

[0034] Fig.17 It is the degradation graph and TOC removal rate graph of the catalyst prepared in Example 1 of the present invention for cyclic degradation of 20 mg / L tetracycline under dark conditions and 10 cycles. DETAILED DESCRIPTION

[0035] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0036] It should be noted that the process equipment or devices not specifically specified in the following examples are all conventional equipment or devices in the art.

[0037] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantially changing the technical content.

[0038] The present invention BiO 2-x The preparation method of the energy storage catalyst comprises the following steps: Step 1: NaBiO 3 ·2H 2 O powder is added to the NaOH solution and stirred to obtain a sodium bismuthate alkaline solution; wherein NaBiO 3 ·2H 2 The molar ratio of O to NaOH is: (0.045-0.18): (2-4); Step 2, adding the sodium bismuthate alkaline solution dropwise into water and stirring for 20 min to 120 min to obtain a reaction precursor solution; wherein the volume ratio of the water to the NaOH solution is 1:1; Step 3: The precursor solution is subjected to a hydrothermal reaction at 160°C to 180°C for 30 min to 120 min, and the obtained reaction product is washed and dried to obtain BiO 2-x Energy storage catalyst.

[0039] In step 1 of the present invention, the concentration of the NaOH solution is 2 mol / L to 4 mol / L. In the sodium bismuthate alkaline solution, NaBiO 3 ·2H 2 The concentration of O is 0.045 mmol / mL~0.18 mmol / mL.

[0040] In step 3 of the present invention, washing is specifically: first centrifugally washing with deionized water until the pH of the obtained supernatant is 6.5-7, and then washing three times with anhydrous ethanol. Drying is specifically: vacuum drying at 65°C-75°C.

[0041] The BiO prepared by the present invention 2-x It is a cubic phase structure with a space group of Fm3m(225). 2-x The catalyst is an energy storage catalyst with piezoelectric response characteristics. 33 The value is 9.1767 nm·V -1 , under dark conditions BiO2-x The strain caused by mechanical stress perturbation leads to the orientation and enhancement of the internal piezoelectric polarization field, and the stored holes and vacancies are quickly released under dark conditions for catalytic reaction. 2-x The energy storage catalyst generates piezoelectric charge, which is further released to continuously degrade organic pollutants.

[0042] Therefore, BiO 2-x The energy storage catalyst has the function of catalytically degrading antibiotics, organic matter, dyes and mixed pollutants under dark conditions, and has good broad-spectrum cyclic stability under dark conditions.

[0043] The antibiotic of the present invention is tetracycline or ciprofloxacin. The organic matter is bisphenol A. The dye is methylene blue and methylene orange. The mixed pollutant is a mixed solution of tetracycline, ciprofloxacin, methylene blue and methylene orange B.

[0044] Comparative Example 1 Step 1: 1.8 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 2.5 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, directly adding 20 mL of deionized water to the sodium bismuthate alkaline solution, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to hydrothermal reaction at 180°C for 40 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0045] Example 1 Step 1: 1.8 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 3 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to hydrothermal reaction at 180°C for 40 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-xThe washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0046] Example 2 Step 1: 1.8 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 2 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to hydrothermal reaction at 180°C for 40 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0047] Example 3 Step 1: 1.8 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 2.5 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to hydrothermal reaction at 180°C for 40 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0048] Example 4 Step 1: 1.8 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of 3.5 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to hydrothermal reaction at 180°C for 40 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0049] Example 5 Step 1: 1.8 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 4 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to hydrothermal reaction at 180°C for 40 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0050] Example 6 Step 1: 0.9 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 3 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to hydrothermal reaction at 180°C for 40 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0051] Example 7 Step 1: 1.2 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of 3 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to hydrothermal reaction at 180°C for 40 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0052] Example 8 Step 1: 2.4 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 3 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to hydrothermal reaction at 180°C for 40 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0053] Example 9 Step 1: 3.0 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 3 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to hydrothermal reaction at 180°C for 40 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0054] Example 10 Step 1: 3.6 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 3 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to a hydrothermal reaction at 180°C for 40 minutes. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0055] Example 11 Step 1: 1.8 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 3 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to a hydrothermal reaction at 160° C. for 40 min. After the reaction is completed, the product in the reaction solution is washed, separated, and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0056] Example 12 Step 1: 1.8 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 3 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to a hydrothermal reaction at 170°C for 40 minutes. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0057] Example 13 Step 1: 1.8 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 3 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to a hydrothermal reaction at 180°C for 50 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0058] Example 14 Step 1: 1.8 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 3 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to a hydrothermal reaction at 180°C for 80 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0059] Example 15 Step 1: 1.8 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2 O) the powder is dispersed in 20 mL of a 3 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to a hydrothermal reaction at 180°C for 100 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0060] Example 16 Step 1: 1.8 mmol sodium bismuthate dihydrate (NaBiO 3 ·2H 2O) the powder is dispersed in 20 mL of a 3 mol / L NaOH solution to obtain a sodium bismuthate mixed solution; Step 2, stirring the mixed solution for 60 minutes to obtain a sodium bismuthate alkaline solution, slowly adding the sodium bismuthate alkaline solution dropwise to 20 mL of deionized water, and stirring evenly for 30 minutes to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to a hydrothermal reaction at 180°C for 120 min. After the reaction is completed, the product in the reaction solution is washed, separated and dried to obtain BiO 2-x The washing process is performed multiple times with deionized water and anhydrous ethanol, respectively, and the filter cake after the precipitate washing is dried at 70° C. for 12 hours.

[0061] The above conclusions and mechanisms are explained in detail below.

[0062] Figure 1 : is the XRD diagram of the catalysts prepared in Examples 1, 2 and 5 of the present invention. 2-x The diffraction peaks corresponding to the (111) crystal plane, (200) crystal plane, (220) crystal plane, (311) crystal plane and (222) crystal plane appear at 2θ of 28.2°, 32.7°, 46.9°, 55.6° and 58.3°, respectively, which are consistent with the cubic BiO 2-x (space group: Fm3m(225)) (JCPDS: 47-1057) standard card. This indicates that the cubic BiO 2-x .

[0063] Figure 2 : is the Raman graph of the catalysts prepared in Examples 1, 2 and 5 of the present invention. 2-x Catalyst at 119 cm -1 The characteristic peak at 138 cm -1 、310 cm -1 、439 cm -1 The characteristic peak at 182 cm -1 、207 cm -1 The characteristic peak at is attributed to the vibration of O atoms. This further proves that the present invention successfully prepared cubic BiO 2-x .

[0064] Figure 3 is a SEM image of the catalyst prepared in Example 1 of the present invention. 2-x The morphology shows tetragonal nanosheets with side lengths of 0.2μm~0.5μm and nanorods with a length of about 0.3μm and a diameter of about 50~80nm.

[0065] Figure 4HRTEM image of Example 1 of the present invention. The image shows that the lattice spacing is 0.317 nm, 0.271 nm, 0.1937 nm, and 0.1658 nm, corresponding to BiO 2-x The (111), (200), (220) and (311) crystal planes of BiO 2-x .

[0066] Figure 5 is the absorbance curve of the catalyst prepared in Example 1 of the present invention to 20 mg / L methylene blue under dark conditions. BO can be calculated from the absorbance curve of methylene blue 2-x The stored electron concentration is 9.89 μmol·g -1 Therefore, the BiO prepared by the present invention 2-x It is an energy storage catalyst.

[0067] Figure 6 The catalyst prepared in Example 1 of the present invention is + The electron paramagnetic resonance spectrum of BO 2-x The stored hole concentration is 233.18 μmol·g -1 , further proves that the BiO prepared by the present invention 2-x It is an energy storage catalyst.

[0068] Figure 7 is a phase change diagram of the catalyst prepared in Example 1 of the present invention. 2-x After applying a deflection voltage of 10 V, the phase angle flipped by about 180°, proving that the dipole is easily transformed by an external electric field.

[0069] Figure 8 is the amplitude variation diagram of Example 1 of the present invention. Under the action of the electric field, BiO 2-x The amplitude change diagrams of BiO show a typical "butterfly-shaped curve", which produces a strain-electric field hysteresis phenomenon. 2-x The piezoelectric response is obvious at the nanoscale, and the piezoelectric "butterfly curve" is used to calculate the BiO 2-x D 33 The value is 9.1767 nm·V -1 , showing good piezoelectric performance. The larger piezoelectric polarization characteristics can induce the energy storage catalyst to store charge and generate piezoelectric charge under mechanical stress, thereby improving the dark catalytic activity.

[0070] Fig. 9This is the current graph of Example 1 of the present invention under dark conditions. Under dark conditions, no mechanical stress perturbation is applied, and the current curve changes with time basically as a straight line. When mechanical stress perturbation is applied, it can be seen that the current amplitude changes with time. The current increases with mechanical stress perturbation, and the current fluctuates in a sawtooth shape as time goes by. When the mechanical stress perturbation is stopped, the current decreases rapidly, and the mechanical stress perturbation shows periodic fluctuations. This also proves that BiO 2-x Under dark conditions, mechanical stress perturbation forms a positive piezoelectric effect and generates piezoelectric charge, indicating that BiO 2-x It has obvious piezoelectric response characteristics under stress.

[0071] Fig.10 The degradation performance of the catalysts prepared in Example 1, Example 2, Example 5 and Comparative Example 1 of the present invention on 20 mg / L tetracycline. Under dark conditions, the degradation rates of the catalysts in Example 1, Example 2 and Example 5 on 20 mg / L TC were 80.24%, 77.11% and 79.24% respectively in 60 min; the degradation rate of the catalyst in Comparative Example 1 on 20 mg / L TC was only 66.4% under dark conditions. This shows that the sodium bismuthate alkaline solution was added drop by drop into the water, and the added BiO 3 - Can be used with H + Rapid binding, resulting in uniform generation of HBiO of the same size in solution 3 ·BiO 3 - colloid particles, thereby forming oxygen vacancies and Bi 3+ / Bi 5+ , while directly adding water to the sodium bismuthate alkaline solution, a large amount of water dissociates to form H + With BiO in solution 3 - Rapidly combine to form a large amount of HBiO 3 Small nuclei, lots of small HBiO 3 The crystal nuclei fully aggregate and grow in the hydrothermal high temperature environment to form BiO 2-x Crystal, HBiO 3 Bi in small crystal nuclei 5+ Easy to restore all 3+ , but HBiO in solution 3 The oxygen concentration in the crystal nucleus is higher than that in the hydrothermal environment. 3 The nucleus oxygen escapes to form O 2 , causing oxygen deficiency inside the crystal (2HBiO 3 →2BiO 2-x +O 2 ↑+H 2O), resulting in the catalyst crystals prepared by directly adding water to the sodium bismuthate alkaline solution storing only electrons, which greatly reduces its degradation rate under dark conditions.

[0072] Fig.11 The removal rates of 40 mg / L tetracycline TOC by the catalysts prepared in Examples 1, 2 and 5 of the present invention are 28%, 25% and 23% respectively for the organic carbon removal in the degradation product of 20 mg / L TC in Examples 1, 2 and 5, indicating that the catalysts of the present invention have high catalytic activity in the dark.

[0073] Fig.12 and Fig.13 The following are the mass spectra of the catalyst prepared in Example 1 of the present invention degrading 20 mg / L tetracycline for 10 min and 50 min under dark conditions. The LC-MS detection of tetracycline was transformed from a high mass-to-charge ratio (m / z=445) into a small molecule, further proving that BiO 2-x The catalyst can degrade tetracycline to CO in the dark 2 and H 2 O and small organic molecules, BiO 2-x The catalyst is an energy storage piezoelectric catalytic material.

[0074] Fig.14 The degradation performance of the catalysts prepared in Examples 1, 2 and 5 of the present invention on bisphenol A and ciprofloxacin is shown. The degradation rates of bisphenol A in Examples 1, 2 and 5 under dark conditions for 60 minutes are 93.89%, 94.97% and 91.73% respectively; the degradation rates of ciprofloxacin can reach 24.1%, 29% and 25.92%.

[0075] Fig.15 and Fig.16 The absorbance graph and TOC removal rate graph of the catalyst prepared in Example 1 of the present invention for a mixed solution of 20 mg / L tetracycline, 20 mg / L bisphenol A, 10 mg / L methylene blue, 10 mg / L methylene orange, and 10 mg / L ciprofloxacin under dark conditions are shown respectively. As the degradation time increases, the absorption band gradually weakens, and the TOC removal rate is 28.15%, indicating that BiO 2-x The catalyst has good degradation performance for mixed pollutant solution. 2-x The energy storage catalyst is universal and can degrade a variety of antibiotics, organic matter and dyes under dark conditions.

[0076] Fig.17The figure is the degradation graph of 20 mg / L tetracycline cycle degradation and TOC removal rate graph of the catalyst prepared in Example 1 of the present invention under dark conditions and 10 cycles under dark conditions. The catalytic degradation activity of the catalyst for TC under dark conditions increases with the extension of reaction time, and the degradation efficiency of TC gradually decreases. After 10 cycles of reaction, BiO 2-x The degradation rate of TC by the energy storage catalyst was 22%. During the 1st, 4th, 7th and 10th reaction cycles, BiO 2-x The TOC removal rates of the energy storage catalysts for TC were 26.92%, 6.02%, 9.82% and 6.71%, respectively, indicating that BiO 2-x The energy storage catalyst has good cycle stability and strong dark catalytic ability under dark conditions.

[0077] The present invention prepares non-stoichiometric BiO by a one-step hydrothermal method. 2-x Energy storage catalyst, BiO in dark conditions 2-x The strain caused by mechanical stress perturbation leads to the enhancement of its internal piezoelectric polarization electric field, and the stored electrons and holes are quickly released under dark conditions for catalytic reaction. 2-x The energy storage catalyst generates piezoelectric charge, which is further released to continuously degrade the antibiotic tetracycline, ciprofloxacin, the organic compound bisphenol A, and the dyes methylene blue and methylene orange.

[0078] The above is only one embodiment of the present invention, not all or the only embodiment. Any equivalent changes made to the technical solution of the present invention by ordinary technicians in this field after reading the specification of the present invention are covered by the claims of the present invention.

Claims

1. A BiO 2-x Preparation method of energy storage catalyst, It is characterized in that The following steps are involved: Step 1: NaBiO 3 ·2H 2 O powder is added to the NaOH solution and stirred to obtain a sodium bismuthate alkaline solution; wherein NaBiO 3 ·2H 2 The molar ratio of O to NaOH is: (0.045-0.18): (2-4); Step 2, adding the sodium bismuthate alkaline solution dropwise into water and stirring to obtain a reaction precursor solution; Step 3: The precursor solution is subjected to a hydrothermal reaction at 160°C to 180°C, and the obtained reaction product is washed and dried to obtain BiO 2-x Energy storage catalyst.

2. A BiO according to claim 1 2-x Preparation method of energy storage catalyst, It is characterized in that In step 1, the concentration of the NaOH solution is 2 mol / L to 4 mol / L.

3. A BiO according to claim 1 2-x Preparation method of energy storage catalyst, It is characterized in that In step 2, the stirring time is 20 min to 120 min.

4. A BiO according to claim 1 2-x Preparation method of energy storage catalyst, It is characterized in that In step 3, the hydrothermal reaction time is 30 min to 120 min.

5. A BiO according to claim 1 2-x Preparation method of energy storage catalyst, It is characterized in that In step 3, washing is specifically as follows: firstly centrifugally washing with deionized water until the pH of the obtained supernatant is 6.5-7, and then washing with anhydrous ethanol for multiple times.

6. A BiO according to claim 1 2-x Preparation method of energy storage catalyst, It is characterized in that In step 3, drying is specifically: vacuum drying at 65°C to 75°C.

7. A BiO obtained by the preparation method according to any one of claims 1 to 6 2-x Energy storage catalyst, It is characterized in that The BiO 2-x The energy storage catalyst is a cubic phase with a space point group of Fm-3m, BiO 2-x Energy storage catalysts store electrons and holes.

8. BiO according to claim 7 2-x Application of energy storage catalysts in catalytic degradation of organic pollutants under dark conditions.

9. The use according to claim 8, It is characterized in that The organic pollutant is an antibiotic or a dye.

10. The BiO according to claim 7 2-x Application of energy storage catalysts in catalytic degradation of organic pollutants.

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