A bimetallic-doped barium titanate piezoelectric photocatalyst, its preparation method and application

Abstract

This invention relates to the field of catalytic materials technology, specifically to a bimetallic-doped barium titanate piezoelectric photocatalyst, its preparation method, and its application. The invention provides a bimetallic-doped barium titanate catalyst, prepared from raw materials including a bismuth source, a noble metal source, and barium titanate, wherein the noble metal element in the catalyst comprises 3% to 25% by mass. Bismuth and noble metal doping can continuously modulate the band structure of barium titanate, achieving an effective redshift in the absorption spectrum and significantly broadening the spectral response range. The introduction of bimetals also enhances lattice asymmetry, promotes photogenerated charge separation, and strengthens the coupling effect between the piezoelectric field and the photogenerated electric field at the molecular scale, thereby generating reactive oxygen species such as hydroxyl radicals and superoxide radicals, which react with organic pollutants in water to achieve efficient degradation. This catalyst possesses both full-spectrum response and excellent ability to degrade organic pollutants, showing broad application prospects in the field of environmental remediation.

Description

Technical Field

[0001] This application relates to the field of catalytic materials technology, and in particular to a bimetallic-doped barium titanate piezoelectric photocatalyst, its preparation method, and its application. Background Technology

[0002] Photocatalysis, as a green and efficient environmental remediation method, has shown broad application prospects in the fields of clean energy development and water pollutant purification. In actual aquatic environments, dyeing, pharmaceutical, and aquaculture wastewater are often discharged in a mixed manner, resulting in a typical coexistence of dyes and antibiotics as a complex pollution phenomenon. The coexistence of these two types of pollutants not only easily produces synergistic ecotoxicity but also induces the spread of antibiotic-resistant bacteria and resistance genes, seriously threatening aquatic ecological security and human health (Ratnawati, R., Dewi, EL, Soetaredjo, FE, Kurniawan, A., & Ismadji, S. (2022). Degradation of methylene blue-ciprofloxacin and hydrogen production simultaneously using combination of electrocoagulation and photocatalytic process with Fe-TiNTAs. International Journal of Hydrogen Energy, 47(39), 16845-16855.). Therefore, developing remediation technologies that can simultaneously achieve efficient degradation of dyes and antibiotics has become a key research focus that urgently needs to be addressed in the field of water pollution remediation.

[0003] However, traditional photocatalysts generally suffer from inherent defects such as low solar energy utilization and high recombination rates of photogenerated electron-hole pairs, resulting in limited catalytic performance. Even with the introduction of more advantageous piezoelectric photocatalysis technology—which relies on external mechanical force to induce the polarization of piezoelectric materials to construct a built-in electric field, effectively promoting the separation of photogenerated carriers to improve catalytic efficiency—existing piezoelectric photocatalytic materials are mostly limited to the removal of single pollutants and cannot simultaneously address the synergistic degradation of dyes and antibiotics. For example, Chinese patent application CN112044426A discloses a barium titanate / potassium niobate composite piezoelectric photocatalyst that relies on the synergistic effect of piezoelectricity and photocatalysis to degrade dyes. However, it can only achieve about 95% dye degradation in 180 minutes, and the degradation rate still needs to be improved. Furthermore, it does not involve the degradation of antibiotics. Antibiotic residues in water bodies can easily induce the growth of drug-resistant bacteria and disrupt the aquatic ecological balance, making this type of piezoelectric photocatalytic material unsuitable for complex real-world aquatic scenarios where dyes and antibiotics coexist.

[0004] Therefore, there is an urgent need to develop a highly efficient piezoelectric photocatalytic material that combines the properties of rapidly degrading dyes and antibiotics to meet the actual treatment needs of complex polluted water bodies. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of existing piezoelectric photocatalysts that cannot simultaneously achieve rapid degradation of antibiotics and dyes, and to provide a bimetallic doped barium titanate catalyst.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned bimetallic doped barium titanate catalyst.

[0007] Another object of the present invention is to provide the application of the above-mentioned bimetallic doped barium titanate catalyst in the catalytic degradation of organic pollutants.

[0008] Another object of the present invention is to provide a method for piezoelectric photocatalytic degradation of organic pollutants.

[0009] Another object of the present invention is to provide a piezoelectric photocatalyst composition.

[0010] The above-mentioned objective of this invention is achieved through the following technical solution: This invention protects a bimetallic doped barium titanate catalyst, which is prepared from raw materials including a bismuth source, a noble metal source and barium titanate. The mass percentage of the noble metal element in the bimetallic doped barium titanate catalyst is 3% to 25%.

[0011] This invention provides a bimetallic-doped barium titanate catalyst, prepared from raw materials including a bismuth source, a noble metal source, and barium titanate, wherein the noble metal element in the catalyst comprises 3% to 25% by mass. Bismuth and noble metal co-doping can continuously tune the band structure of barium titanate, achieving an effective redshift in the absorption spectrum and significantly broadening the spectral response range. Simultaneously, the introduction of bimetals enhances lattice asymmetry, promotes photogenerated charge separation, and strengthens the coupling effect between the piezoelectric field and the photogenerated electric field at the molecular scale, thereby generating reactive oxygen species such as hydroxyl radicals and superoxide radicals, which react with organic pollutants in water to achieve efficient degradation. This catalyst possesses both full-spectrum response and excellent ability to degrade organic pollutants, showing broad application prospects in the field of environmental remediation.

[0012] Preferably, the mass percentage of the noble metal element in the bimetallic doped barium titanate catalyst is 5% to 20%.

[0013] Furthermore, the bismuth source includes bismuth nitrate, bismuth chloride, bismuth sulfate, or a hydrate of any of the above bismuth salts.

[0014] Furthermore, the bismuth source is bismuth pentahydrate.

[0015] Preferably, the mass percentage of bismuth in the bismuth source of the bimetallic doped barium titanate catalyst is 15%-30%.

[0016] More preferably, the mass percentage of bismuth in the bismuth source of the bimetallic doped barium titanate catalyst is 19% to 24%.

[0017] Furthermore, the precious metal source includes any one of silver, platinum, gold, and palladium sources.

[0018] Furthermore, the precious metal source is a silver source.

[0019] Preferably, the silver source includes one or more of silver nitrate, silver chloride, silver bromide, and silver iodide.

[0020] More preferably, the precious metal source is silver nitrate.

[0021] Furthermore, the molar ratio of bismuth element in the bismuth source to noble metal element in the noble metal source is 1:(0.3~2.5).

[0022] Furthermore, the molar ratio of bismuth element in the bismuth source to noble metal element in the noble metal source is 1:(0.4~2).

[0023] Furthermore, the barium titanate is barium titanate nanowire. Due to its one-dimensional structure and high aspect ratio, barium titanate nanowire is more prone to deformation when bent, which can concentrate stress and generate a stronger local piezoelectric potential, thus exhibiting a superior piezoelectric effect.

[0024] This invention protects the preparation method of the aforementioned bimetallic doped barium titanate catalyst, comprising the following steps: Bismuth source and noble metal source were added to barium titanate dispersion. After the reaction was complete, a reducing agent was added to carry out a reduction reaction. After post-treatment, a bimetallic doped barium titanate catalyst was obtained.

[0025] Furthermore, as a preferred method, the bismuth source is added in solution form. Pre-preparing the bismuth source as a bismuth source solution facilitates its more uniform dispersion in the barium titanate dispersion, thereby obtaining a more uniformly composed bimetallic doped barium titanate catalyst.

[0026] Furthermore, the method for preparing the bismuth source solution includes the following steps: The bismuth source is dissolved in an organic solvent to obtain a bismuth source solution.

[0027] Furthermore, the organic solvent includes one or more of ethylene glycol, methanol, and tetrahydrofuran.

[0028] Preferably, the mass-to-volume ratio of the bismuth source to the organic solvent is 1 mg:(2~5) mL.

[0029] Furthermore, as a preferred method, the noble metal source is added in solution form. Pre-preparing the noble metal source as a solution facilitates its more uniform dispersion in the barium titanate dispersion, thereby obtaining a more uniformly composed bimetallic-doped barium titanate catalyst.

[0030] Furthermore, the method for preparing the noble metal source solution includes the following steps: Dissolving the precious metal source in water yields a precious metal source solution.

[0031] Preferably, the mass-to-volume ratio of the precious metal source to water is 1 mg:(0.5~2) mL.

[0032] More preferably, the mass-to-volume ratio of the precious metal source to water is 1 mg:(0.8~1.2) mL.

[0033] Furthermore, the preparation of the barium titanate dispersion includes the following steps: Barium titanate was dispersed in water and mixed well to obtain a barium titanate dispersion.

[0034] Furthermore, the mass-to-volume ratio of barium titanate to water is 1 mg: (0.1~1) mL.

[0035] Furthermore, the mixing method is ultrasonic mixing.

[0036] Furthermore, the mixing time is 10-50 min.

[0037] Furthermore, the temperature at which the reaction is fully completed is room temperature.

[0038] Furthermore, the time for the complete reaction is 1 to 3 hours.

[0039] Furthermore, the reducing agent includes one or more of sodium borohydride, lithium aluminum hydride, and sodium borohydride cyanide.

[0040] Furthermore, the reducing agent is sodium borohydride.

[0041] Preferably, the reducing agent is in solution form, i.e., a reducing agent solution.

[0042] More preferably, the reducing agent solution is obtained by dissolving the reducing agent in water.

[0043] Furthermore, the mass-to-volume ratio of the reducing agent to water is 1 mg:(1~3) mL.

[0044] Preferably, the molar ratio of bismuth element to reducing agent in the bismuth source is 1:(1.6~4.8).

[0045] Preferably, the molar ratio of the noble metal element to the reducing agent in the noble metal source is 1:(1.6~4.8).

[0046] Furthermore, the reduction reaction is carried out at room temperature.

[0047] Furthermore, the reduction reaction takes 0.5 to 5 minutes.

[0048] Furthermore, the post-processing includes centrifugation, washing, and drying.

[0049] Furthermore, the centrifugation conditions are 7000~9000 r / min for 5~10 min.

[0050] Furthermore, the solvents used for washing include ethanol and water.

[0051] Preferably, the washing operation involves washing the precipitate obtained from the centrifugation with ethanol and water 2 to 5 times in sequence.

[0052] Furthermore, the drying conditions are 50~70 °C for 10~24 h.

[0053] This invention protects the application of the aforementioned bimetallic doped barium titanate catalyst in the catalytic degradation of organic pollutants.

[0054] Furthermore, the catalysis includes piezoelectric photocatalysis or photocatalysis. Specifically, piezoelectric photocatalysis refers to the simultaneous application of ultrasonic excitation and light irradiation to catalyze the degradation of organic pollutants.

[0055] Furthermore, the catalysis is piezoelectric photocatalysis.

[0056] This invention protects a method for piezoelectric photocatalytic degradation of organic pollutants, which involves adding the aforementioned bimetallic doped barium titanate catalyst to a system containing organic pollutants, and then subjecting the organic pollutants to piezoelectric photocatalytic degradation under full-spectrum light irradiation.

[0057] Furthermore, the organic pollutants include antibiotics and / or dyes.

[0058] Furthermore, the antibiotics include one or more of tetracycline antibiotics, quinolone antibiotics, and β-lactam antibiotics.

[0059] Preferably, the tetracycline antibiotics include one or more of tetracycline, chlortetracycline, and oxytetracycline.

[0060] Preferably, the quinolone antibiotic includes one or more of ciprofloxacin, norfloxacin, and enrofloxacin.

[0061] Preferably, the β-lactam antibiotics include one or more of cefuroxime, amoxicillin, and ampicillin.

[0062] Furthermore, the dye includes one or more of Rhodamine B (RhB), Malachite Green (MG), and Methylene Blue (MB).

[0063] This invention protects a piezoelectric photocatalyst composition comprising the aforementioned bimetallic doped barium titanate catalyst.

[0064] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a bimetallic-doped barium titanate catalyst, prepared from raw materials including a bismuth source, a noble metal source, and barium titanate, wherein the noble metal element in the catalyst comprises 3% to 25% by mass. Bismuth and noble metal co-doping can continuously tune the band structure of barium titanate, achieving an effective redshift in the absorption spectrum and significantly broadening the spectral response range. Simultaneously, the introduction of bimetals enhances lattice asymmetry, promotes photogenerated charge separation, and strengthens the coupling effect between the piezoelectric field and the photogenerated electric field at the molecular scale, thereby generating reactive oxygen species such as hydroxyl radicals and superoxide radicals, which react with organic pollutants in water to achieve efficient degradation. This catalyst possesses both full-spectrum response and excellent ability to degrade organic pollutants, showing broad application prospects in the field of environmental remediation. Attached Figure Description

[0065] Figure 1 This is a transmission electron microscope image of the bimetallic doped barium titanate catalyst in Example 1.

[0066] Figure 2 This is a high-resolution transmission electron microscope image of the bimetallic doped barium titanate catalyst in Example 1.

[0067] Figure 3 The X-ray diffraction patterns are shown for the bimetallic doped barium titanate catalysts in Example 1 and Comparative Examples 1-2.

[0068] Figure 4 The images show the UV diffuse reflectance (a), band gap (b), valence band (c), and band structure (d) of the bimetallic doped barium titanate catalyst in Example 1.

[0069] Figure 5 The graph shows the degradation efficiency of the catalysts in Examples 1-3 and Comparative Examples 1-2 on tetracycline under ultrasonic conditions in the dark.

[0070] Figure 6 The graph shows the degradation efficiency of tetracycline by the catalysts in Examples 1-3 and Comparative Examples 1-2 under full-spectrum light irradiation without the application of ultrasound.

[0071] Figure 7The graph shows the degradation efficiency of tetracycline by the catalysts in Examples 1-3 and Comparative Examples 1-2 under full-spectrum light source irradiation and ultrasonic application.

[0072] Figure 8 The graph shows the efficiency of four cycles of tetracycline degradation by the bimetallic doped barium titanate catalyst in Example 1 under full-spectrum irradiation and ultrasonic application.

[0073] Figure 9 The graph shows the degradation efficiency of different antibiotics by the bimetallic doped barium titanate catalyst in Example 1 under full-spectrum irradiation and ultrasonic application.

[0074] Figure 10 The graph shows the degradation efficiency of different dyes by the bimetallic doped barium titanate catalyst in Example 1 under full-spectrum light source irradiation and ultrasonic conditions. Detailed Implementation

[0075] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0076] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0077] Figure 4 a represents Figure 4 Figure a in the middle, Figure 4 b represents Figure 4 The order of the other figures follows the same pattern, starting with figure b.

[0078] Example 1: Preparation of a bimetallic doped barium titanate catalyst 40 mg of barium titanate nanowires were dispersed in 12 mL of deionized water and ultrasonically dispersed for 30 min to obtain a barium titanate dispersion. 7 mL of a 4.3 mg / mL bismuth nitrate pentahydrate-ethylene glycol solution (0.062 mmol) and 10 mL of a 1 mg / mL silver nitrate aqueous solution (0.059 mmol) were added dropwise to this dispersion, and the mixture was stirred at room temperature for 2 h. Subsequently, 10 mL of a 20 mmol / L sodium borohydride aqueous solution was added, and the mixture was stirred at room temperature for 1 min. The mixture was then centrifuged at 8000 r / min for 8 min, and the precipitate was collected. The precipitate was washed three times each with anhydrous ethanol and deionized water, and dried at 60 ℃ for 12 h to obtain the bimetallic doped barium titanate catalyst, named BaTiO3 / Bi / Ag-10, in which Ag element accounted for 10.7% of the total catalyst mass.

[0079] Example 2: Preparation of a bimetallic doped barium titanate catalyst The difference from Example 1 is that the volume of the silver nitrate aqueous solution is replaced from 10 mL to 5 mL, thus obtaining the bimetallic doped barium titanate catalyst, named BaTiO3 / Bi / Ag-5, in which Ag element accounts for 5.5% of the total mass of the catalyst.

[0080] The other steps and conditions are the same as in Example 1.

[0081] Example 3: Preparation of a bimetallic doped barium titanate catalyst The difference from Example 1 is that the volume of the silver nitrate aqueous solution is replaced from 10 mL to 20 mL, thus obtaining the bimetallic doped barium titanate catalyst, named BaTiO3 / Bi / Ag-20, in which Ag element accounts for 19.4% of the total mass of the catalyst.

[0082] The other steps and conditions are the same as in Example 1.

[0083] Comparative Example 1: Preparation of a Bi monometallic doped barium titanate catalyst The difference from Example 1 is that only barium titanate is doped with Bi single metal without adding silver nitrate aqueous solution, i.e., the Ag doping step is omitted. The specific experimental steps are as follows: 40 mg of barium titanate nanowires were dispersed in 12 mL of deionized water and ultrasonically dispersed for 30 min to obtain a barium titanate dispersion. 7 mL of a 4.3 mg / mL bismuth nitrate pentahydrate-ethylene glycol solution (0.062 mmol) was added dropwise to this dispersion, and the mixture was stirred at room temperature for 2 h. Subsequently, 10 mL of a 20 mmol / L sodium borohydride aqueous solution was added, and the mixture was stirred at room temperature for 1 min before centrifugation. The precipitate was collected and washed three times each with anhydrous ethanol and deionized water, and then dried at 60 ℃ for 12 h to obtain the Bi monometallic doped barium titanate catalyst, named BaTiO3 / Bi.

[0084] Comparative Example 2: Preparation of an Ag monometallic doped barium titanate catalyst The difference from Example 1 is that only barium titanate is doped with Ag single metal, without adding bismuth nitrate pentahydrate-ethanol solution, i.e., the Bi doping step is omitted. The specific experimental steps are as follows: 40 mg of barium titanate nanowires were dispersed in 12 mL of deionized water and ultrasonically dispersed for 30 min to obtain a barium titanate dispersion. 5 mL of 1 mg / mL silver nitrate aqueous solution (0.059 mmol) was added dropwise to this dispersion, and the mixture was stirred at room temperature for 2 h. Subsequently, 10 mL of 20 mmol / L sodium borohydride aqueous solution was added, and the mixture was stirred at room temperature for 1 min before centrifugation. The precipitate was collected and washed three times each with anhydrous ethanol and deionized water, and then dried at 60 ℃ for 12 h to obtain the Ag monometallic doped barium titanate catalyst, named BaTiO3 / Ag.

[0085] Example 1: Structural Characterization of a Bimetallic Doped Barium Titanate Catalyst 1. Morphological characterization (TEM) The morphology of the BaTiO3 / Bi / Ag-10 catalyst prepared in Example 1 was characterized using transmission electron microscopy (TEM). The results are as follows: Figure 1 As shown, the surface of the rod-shaped BaTiO3 nanowires is loaded with Bi particles with a diameter of approximately 0.2 μm and smaller Ag particles; further characterization using high-resolution transmission electron microscopy (HRTEM) reveals visible (… Figure 2 Ag particles with a diameter of approximately 20 nm were uniformly loaded onto the surface of BaTiO3 nanowires. The characterization results above directly confirm that Bi and Ag have been successfully loaded onto the surface of BaTiO3 nanowires.

[0086] To further verify the construction of the bimetallic doped barium titanate catalyst at the elemental level, the catalyst obtained in Example 1 was analyzed by XRD and UV-Vis DRS. The specific results are as follows: 2. Phase analysis (XRD) The catalysts in Example 1 and Comparative Examples 1-2 were analyzed using X-ray diffraction (XRD). Figure 3 As shown, the XRD pattern of the catalyst obtained in Example 1 shows typical characteristic peaks of BaTiO3 and Ag and Bi, indicating that Bi and Ag were successfully doped into BaTiO3, further proving the successful construction of the bimetallic doped barium titanate catalyst in this application.

[0087] 3. Optical properties and band structure analysis (UV-Vis DRS) The BaTiO3 / Bi / Ag-10 catalyst in Example 1 was analyzed by UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), and the results are as follows: Figure 4 As shown. Figure 4 As shown in Figure a, both single doping with Ag and single doping with Bi can effectively reduce the band gap of BaTiO3 nanowires, while the effect of dual doping with Bi and Ag on the band structure regulation of BaTiO3 nanowires is more significant; combined with (ahv)2 -hv diagram ( Figure 4 b) Calculations show that the band gaps (Eg) of pure BaTiO3, BaTiO3 / Bi, BaTiO3 / Ag, and BaTiO3 / Bi / Ag are 3.34 eV, 3.19 eV, 3.17 eV, and 3.12 eV, respectively. The double-doped sample has the smallest band gap, and its optical response range extends more significantly into the visible light region. Combined with XPS valence band spectroscopy (…),… Figure 4 c), Determine the top position of the price band (E) vb The values ​​are 2.07 eV, 2.36 eV, 2.49 eV, and 2.71 eV, respectively, and according to the band structure E... vb =E cb +E g Calculate the bottom position of the conduction band (E) cb The final constructed band structure is as follows: Figure 4 As shown in d, the Bi and Ag co-doping forms a more rational band arrangement, which effectively promotes the spatial separation and directional transport of photogenerated carriers, providing an intrinsic mechanism to support the excellent photocatalytic activity.

[0088] Experimental Example 2: Degradation Performance Test of Catalyst for Tetracycline under Different Conditions This experimental example tests the tetracycline degradation performance of the catalysts in each embodiment and comparative example under piezoelectric catalysis only, photocatalysis only, and piezoelectric-photocatalysis synergistic conditions.

[0089] 1. Experimental Methods Prepare 50 mL of tetracycline (TC) solution with a concentration of 20 mg / L. Following the principle of "one solution corresponds to one sample", add 10 mg of the target sample (the catalyst of each example or comparative example) to each of the multiple TC solutions. Set the following three test conditions: (1) apply ultrasound only (frequency 40 kHz, power 80 W); (2) apply light only with a 300 W xenon lamp (equipped with a full-spectrum reflector); (3) apply ultrasound (frequency 40 kHz, power 80 W) and light (300 W xenon lamp) simultaneously. Perform experiments independently on each system: first, stir in the dark for 30 min to allow TC and the catalyst surface to reach adsorption-desorption equilibrium; then stop stirring and catalyze for 120 min under the above conditions, during which the system temperature is controlled at 25℃ with condensate. Take 3 mL of sample every 30 min, filter through a 0.22 μm aqueous filter membrane to remove the catalyst, and measure the TC absorbance of the filtrate at 357 nm using a UV spectrophotometer.

[0090] 2. Experimental Results The catalytic performance evaluation results of the prepared samples under piezoelectric catalysis, photocatalysis, and piezoelectric-photocatalysis conditions are as follows: Figures 5-7 As shown. Piezoelectric catalysis conditions ( Figure 5 In the piezoelectric catalysis process with only mechanical vibration applied, all samples showed low degradation efficiency. Among them, pure phase BaTiO3 had the weakest activity. Although the degradation performance of the doped modified samples (BaTiO3 / Bi, BaTiO3 / Ag and BaTiO3 / Bi / Ag) was improved to some extent, the overall performance was still at a low level. This indicates that the number of active species generated by the simple piezoelectric effect is limited and its contribution to pollutant degradation is limited.

[0091] Photocatalytic conditions ( Figure 6 In the photocatalytic process under light irradiation alone, the degradation kinetics of all samples were significantly improved compared to the piezoelectric catalytic conditions. Among them, the BaTiO3 / Ag and BaTiO3 / Bi / Ag samples showed better photocatalytic activity than pure phase BaTiO3, indicating that the modification strategy effectively promoted the separation and migration of photogenerated carriers, thereby improving the photocatalytic efficiency.

[0092] piezoelectric photocatalysis conditions ( Figure 7 Under piezoelectric photocatalytic conditions of simultaneous light irradiation and mechanical vibration, all samples achieved the highest degradation efficiency among the three catalytic conditions. The BaTiO3 / Bi / Ag-10 sample exhibited the best performance, achieving a tetracycline degradation rate of 87.5% within 120 min. This significant improvement can be attributed to the synergistic effect of the piezoelectric effect and the photocatalytic process: the built-in piezoelectric field induced by mechanical vibration effectively drives the separation of photogenerated electron-hole pairs, significantly suppressing carrier recombination, thereby greatly enhancing the overall catalytic activity.

[0093] Experimental Example 3: Cyclic Stability Test of Bimetallic Doped Barium Titanate Catalyst for Tetracycline Degradation via Piezoelectric Photocatalysis 1. Experimental Methods Prepare 50 mL of 20 mg / L tetracycline (TC) solution. Following the principle of "one solution per sample," add 10 mg of the BaTiO3 / Bi / Ag-10 catalyst prepared in Example 1 to each of the multiple TC solutions. Using a 300 W xenon lamp (equipped with a full-spectrum reflector) as the light source, and simultaneously applying ultrasound (frequency 40 kHz; power 80 W), conduct experiments independently on each system. First, place each system in the dark and stir for 30 minutes to allow TC to reach adsorption-desorption equilibrium with the catalyst surface. Then, stop stirring, turn on the light source, and apply ultrasound for 120 minutes of catalytic reaction. During this period, maintain the system temperature at 25 °C using condensate. During irradiation, take 3 mL samples every 30 minutes, remove the piezoelectric photocatalyst through a 0.22 μm aqueous filter membrane, and measure the TC absorbance of the filtrate at 357 nm using a UV spectrophotometer. After a single reaction, the residual TC solution was transferred to a centrifuge tube, centrifuged to remove the supernatant, and then the precipitate was washed alternately with anhydrous ethanol and water. After drying, a sample was obtained for one-time recycling. This process was repeated for four cycles.

[0094] 2. Experimental Results The results are as follows Figure 8 As shown in the figure, the degradation curves of TC in the four-cycle experiment showed a trend consistent with the reaction rate, with similar C / C0 values ​​at the same time points, and the final degradation rate stabilized at around 87.5%. This indicates that the catalyst exhibits no significant activity decay after multiple cycles, demonstrating excellent cycle stability and reusability, providing important support for its application in practical environmental remediation.

[0095] The cycling stability of the bimetallic doped barium titanate catalysts in Examples 2 and 3 is basically the same as that in Example 1, and will not be repeated here.

[0096] Experimental Example 4: Degradation Performance Test of Different Antibiotics by Bimetallic Doped Barium Titanate Catalyst under Piezoelectric Photocatalysis 1. Experimental Methods 50 mL solutions of four antibiotic contaminants—tetracycline (TC), chlortetracycline (CTC), oxytetracycline (OTC), and ciprofloxacin (CIP)—at a concentration of 20 mg / L were prepared. Following the principle of "one solution per sample," 10 mg of the BaTiO3 / Bi / Ag-10 catalyst prepared in Example 1 was added to each contaminant solution. A 300 W xenon lamp (equipped with a full-spectrum reflector) was used as the light source, and ultrasound (40 kHz, 80 W) was applied simultaneously. Each system was tested independently. Each system was first stirred in the dark for 30 minutes to allow the organic contaminants to reach adsorption-desorption equilibrium with the catalyst surface. Then, stirring was stopped, the light source was turned on, and ultrasound was applied for a catalytic reaction for 120 minutes, during which the system temperature was controlled at 25 °C using condensate. During irradiation, 3 mL of reaction solution was sampled every 30 minutes. After removing the piezoelectric photocatalyst through a 0.22 μm aqueous filter membrane, the absorbance was measured at their respective characteristic absorption wavelengths using an ultraviolet spectrophotometer. The absorbance was 357 nm for TC, 365 nm for CTC, 268 nm for OTC, and 271 nm for CIP.

[0097] 2. Experimental Results Figure 9 The degradation efficiency of BaTiO3 / Bi / Ag-10 for different antibiotic pollutants under full-spectrum light coupled with ultrasound is shown in the figure. As can be seen from the figure, this catalyst exhibits good piezoelectric photocatalytic degradation performance for a variety of typical antibiotics, with degradation efficiencies exceeding 80% for most. The best degradation effect was observed for tetracycline, reaching 87.5%; the degradation rates for chlortetracycline and oxytetracycline were 81% and 82%, respectively; although the degradation efficiency for ciprofloxacin was relatively low, it still showed a certain degradation effect, reaching 65.8%. These results indicate that the piezoelectric photocatalytic material prepared in this invention has good versatility in degrading various common antibiotic-based organic pollutants in water and possesses practical application potential.

[0098] The degradation performance of the bimetallic doped barium titanate catalysts in Examples 2 and 3 for different antibiotics is basically the same as that in Example 1, and will not be repeated here.

[0099] Experimental Example 5: Degradation Performance of Bimetallic Doped Barium Titanate Catalyst for Dyes under Piezoelectric Photocatalysis 1. Experimental Methods 50 mL solutions of Rhodamine B (RhB) and malachite green (MG) at a concentration of 20 mg / L were prepared separately. Following the principle of "one solution per sample," 10 mg of the BaTiO3 / Bi / Ag-10 catalyst from Example 1 was added to each organic pollutant solution. Experiments were conducted independently on each system using a 300 W xenon lamp equipped with a full-spectrum reflector as the light source, while simultaneously applying ultrasound (frequency 40 kHz, power 80 W). Each system was first stirred in the dark for 30 minutes to allow the organic pollutants and catalyst surface to reach adsorption-desorption equilibrium. Then, stirring was stopped, the light source was turned on, and ultrasound was applied for catalytic reaction for 120 minutes, during which the temperature was controlled at 25 °C using condensate. During irradiation, 3 mL samples were taken every 30 minutes, and the piezoelectric photocatalyst was removed through a 0.22 μm aqueous filter membrane. The absorbance of the filtrate was measured using a UV spectrophotometer at the characteristic absorption wavelengths (554 nm for RhB and 624 nm for MG).

[0100] 2. Experimental Results The results are as follows Figure 10 As shown, the BaTiO3 / Bi / Ag-10 catalyst of Example 1 exhibits excellent dye degradation performance: when the reaction proceeds for 120 min, the catalyst achieves a degradation rate of 99% for both dyes, with a faster degradation rate and better kinetic performance for MG. This demonstrates that the catalyst possesses a highly efficient and rapid degradation capability for dye pollutants.

[0101] The degradation performance of the bimetallic doped barium titanate catalysts in Examples 2 and 3 on the above-mentioned dyes is basically the same as that in Example 1, and will not be repeated here.

[0102] In summary, the bimetallic doped barium titanate catalyst proposed in this application overcomes the limitations of existing barium titanate-based materials, which can only degrade dyes individually and have insufficient degradation rates. It not only achieves efficient and rapid degradation of dye pollutants, but also exhibits excellent removal performance for typical antibiotics in water bodies. It can simultaneously achieve synergistic and efficient purification of combined dye and antibiotic pollution, providing a novel and high-performance solution for the treatment of complex water bodies.

[0103] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A bimetallic doped barium titanate catalyst, characterized in that, The bimetallic doped barium titanate catalyst is prepared from raw materials including bismuth source, noble metal source and barium titanate. The mass percentage of the noble metal element in the bimetallic doped barium titanate catalyst is 3% to 25%.

2. The double metal-doped barium titanate catalyst of claim 1, wherein, The molar ratio of bismuth element in the bismuth source to noble metal element in the noble metal source is 1:(0.3~2.5).

3. The bimetallic doped barium titanate catalyst of claim 1, wherein, The precious metal source includes any one of silver, platinum, gold, and palladium.

4. The method for preparing the double metal-doped barium titanate catalyst according to any one of claims 1 to 3, characterized in that, Includes the following steps: Bismuth source and noble metal source were added to barium titanate dispersion. After the reaction was complete, a reducing agent was added to carry out a reduction reaction. After post-treatment, a bimetallic doped barium titanate catalyst was obtained.

5. The preparation method according to claim 4, characterized in that, The reducing agent includes one or more of sodium borohydride, lithium aluminum hydride, and sodium borohydride cyanide.

6. The application of the bimetallic doped barium titanate catalyst according to any one of claims 1 to 3 in the catalytic degradation of organic pollutants.

7. Use according to claim 6, characterized in that, The catalysis includes piezoelectric photocatalysis or photocatalysis.

8. A method of piezoelectric photocatalytic degradation of organic pollutants, characterized in that, Add the bimetallic doped barium titanate catalyst according to any one of claims 1 to 3 to a system containing organic pollutants, and then perform piezoelectric photocatalytic degradation of organic pollutants under full-spectrum light irradiation.

9. The method of claim 8, wherein, The organic pollutants include antibiotics and / or dyes.

10. A piezophotocatalyst composition, characterized by, The piezoelectric photocatalyst composition includes the bimetallic doped barium titanate catalyst according to any one of claims 1 to 3.

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