Preparation method and application of BaTiO3 / GDY / Au piezoelectric enhanced photocatalyst

Abstract

The application belongs to the field of nano new energy materials, and discloses a preparation method of BaTiO3 / GDY / Au piezoelectric enhanced photocatalyst and application thereof. The catalyst is prepared by first synthesizing barium titanate nanofibers with piezoelectric effect through an electrospinning method, then growing thin graphdiyne nanosheets on the surface of the barium titanate, and finally growing gold nanoparticles with a local surface plasmon resonance effect on the surface of the graphdiyne to obtain barium titanate / graphdiyne / gold nanofibers. Under the combined stimulation of light and ultrasound, the barium titanate / graphdiyne / gold nanofiber catalyst can promote the generation of a large number of active oxygen free radicals, thereby removing organic pollutants and pathogens in wastewater. The application can solve the problems of low catalytic activity and poor stability of the catalyst, and can quickly remove organic pollutants and pathogens in wastewater.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a BaTiO3 / GDY / Au piezoelectric enhanced photocatalyst and application thereof, and belongs to the technical field of nanomaterial catalysts. BACKGROUND

[0002] Water pollution is usually associated with organic dyes, antibiotics and microbial contamination, so efficient degradation and disinfection technologies are crucial for water treatment. Traditional water disinfection methods (such as chlorination and ultraviolet irradiation) have been widely used in water purification facilities, but the carcinogenic byproducts produced by chlorination are harmful to the environment, and some microorganisms are resistant to ultraviolet irradiation. Advanced oxidation processes (AOPs) are effective water treatment technologies for degrading organic pollutants and inactivating pathogens, which utilize highly toxic active oxygen to achieve the degradation of organic matter and the killing of pathogens in wastewater by generating a large number of free radicals.

[0003] Piezophotocatalysis is an advanced green technology that combines mechanical and optical energy into chemical energy through the synergistic effect of photocatalysis and the piezoelectricity of non-centrosymmetric semiconductors. Metal nanostructures with local surface plasmon resonance (LSPR) properties exhibit tunable absorption characteristics and generate energy-favorable hot carriers in the visible light range. By combining piezoelectricity with LSPR, the built-in electric field generated by polarization caused by mechanical stimulation can promote the separation of hot electrons and holes generated by photoexcitation. This effective modulation of charge transfer behavior at the interface, as well as the synergistic effect of LSPR and piezoelectricity, can further improve photocatalytic activity. However, the slow interface charge transfer rate and high energy hot electron recombination rate greatly affect the generation of active oxygen, thereby affecting the degradation efficiency of wastewater.

[0004] Patent application CN117046503A discloses a preparation method of P / S-g-C3N4 nanomaterial and its application. The prepared phosphorus-sulfur co-doped graphite phase carbon nitride photocatalytic material has significantly improved photocatalytic performance compared to graphite phase carbon nitride, and also solves the problem of degrading pollutants in complex environments with organic dyes and heavy metal ions. The process has the following defects: high preparation conditions, low catalytic activity, and poor catalyst stability.

[0005] Patent application CN117049692A discloses a device and method for treating wastewater by coupling electrocatalytic reduction and biodegradation. The device comprises a stable voltage DC power supply, a cathode, an anode, an RO filter separation membrane group, a coupling reaction box, a biological filler box and a photocatalytic reactor. The stable voltage DC power supply is started to remove COD in wastewater. The process has the following defects: low catalytic activity and poor catalyst stability. SUMMARY

[0006] To solve the above technical problems, the application provides a preparation method of a BaTiO3 / GDY / Au piezoelectric enhanced photocatalyst and application thereof, which can solve the problems of low catalytic activity and poor stability of the catalyst, and quickly remove organic pollutants and pathogens in wastewater.

[0007] The technical scheme of the application is: a preparation method of a BaTiO3 / GDY / Au piezoelectric enhanced photocatalyst and application thereof, which uses a barium titanate / graphite alkyne supported gold catalyst (BTO / GDY / Au), and under the combined action of light and ultrasound, a large amount of active oxygen free radicals are quickly generated, so as to remove organic pollutants and pathogens in wastewater.

[0008] The preparation method of the barium titanate / graphite alkyne supported gold catalyst is:

[0009] 1. Preparation of barium titanate:

[0010] First, 5wt% of polyvinylpyrrolidone (PVP) with different molecular weights is dissolved in a mixed solution of ethanol, deionized water and acetic acid (weight ratio of 5:1:4). Then, under continuous stirring, barium acetate is added to the solution. When the solution becomes transparent (about 1 hour), under continuous stirring at room temperature, tetrabutyl titanate is added dropwise. The stoichiometric molar ratio of Ba to Ti is 1:1. Then the mixed solution is stirred for 2 hours to form a transparent sol. The feeding rate of the electrospinning process is 1.5mLh -1 , the voltage is 15kV, the distance between the nozzle and the collector is 15cm, the rotation speed is 60r m -1 , the humidity and temperature of the electrospinning chamber are 40%±5% and 25±2℃ respectively. After electrospinning, the polymer precursor is dried at 90℃ for 2 hours, and then calcined at 850℃ for 4 hours at a heating rate of 2℃ per minute to obtain barium titanate.

[0011] As a preferred, the concentration of ethanol is 95%, the concentration of acetic acid is 99.5%, the concentration of barium acetate is 99%, and the concentration of tetrabutyl titanate is 98%.

[0012] 2. Preparation of barium titanate / graphite alkyne:

[0013] GDY was mainly synthesized by coupling reaction using hexaethynylbenzene (HEB) as a monomer. First, a solution of HEB-TMS and tetra-n-butylammonium fluoride (TBAF, 1 M in tetrahydrofuran (THF)) was prepared under argon and stirred at 0 °C for 15 min. Subsequently, the mixture was diluted with ethyl acetate, washed twice with saturated sodium chloride (NaCl) solution, dried over anhydrous magnesium sulfate (MgSO4), and filtered. The solvent was then evaporated under vacuum while keeping the temperature below 20 °C. The resulting residue was diluted with 50 mL of acetone and added dropwise to a three-necked flask containing acetone (100 mL), pyridine (5 mL), and barium titanate (20 mg) over 10 h. The reaction mixture was kept at 60 °C under argon for 15 h. It is worth noting that all processes from deprotection to addition should be carried out in dark and low temperature conditions to prevent HEB decomposition. After the reaction was completed, it was washed with N,N-dimethylformamide (DMF), acetone, and ethanol, respectively. Finally, the barium titanate / graphyne composite was freeze-dried.

[0014] As a preferred, the concentration of ethyl acetate is 99.5%, the concentration of acetone is 99.5%, the concentration of pyridine is 99.5%, and the concentration of DMF is 99.5%.

[0015] 3. Preparation of barium titanate / graphyne supported gold catalyst:

[0016] 10 mg of barium titanate / graphyne, 26-130 μL of HAuCl4·3H2O (48.56 mM), and 1 mg of sodium citrate were mixed and stirred. Subsequently, 1 mg of sodium borohydride was added to the mixture. After 10 min, the resulting material was washed with deionized water three times and then freeze-dried.

[0017] As a preferred, the purity of sodium citrate is 99%, and the purity of sodium borohydride is 96%. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic diagram of the synthesis route of BTO / GDY / Au;

[0019] Figure 2 is a TEM photograph of BTO / GDY / Au;

[0020] Figure 3 is a degradation performance graph of BTO / GDY / Au;

[0021] Figure 4 is an in vitro antibacterial result of BTO / GDY / Au;

[0022] Figure 5 is a rapid degradation wastewater device of BTO / GDY / Au. DETAILED DESCRIPTION

[0023] The present application is described in detail below with reference to the accompanying drawings and examples.

[0024] Example 1:

[0025] BTO / GDY / Au was characterized and dye and antibiotic degradation experiments were performed. Transmission electron microscopy was used for characterization. Dye and antibiotic degradation experiments were performed on BTO / GDY / Au synthesized using different molecular weights of PVP.

[0026] The catalytic performance of BTO / GDY / Au was evaluated using a methylene blue (MB) bleaching model. In this study, BTO / GDY / Au (100 pg mL -1 ) was dispersed in a MB solution (10 mg L -1 , pH = 4) in a glass beaker. The mixture was stirred in the dark at ambient temperature for 30 min. Subsequently, H2O2 (100 mM) was introduced, and the mixture solution was then subjected to light irradiation and sonication for 30 min. The MB discoloration was monitored using a UV-Vis spectrophotometer. Degradation cycling experiments were performed by repeated addition of MB (10 mg L -1 ) to the mother solution. In addition, 10 mg L -1 of dyes (rhodamine B (Rh B), methyl orange (MO), congo red) and 20 mg L -1 of antibiotics (tetracycline, penicillin, ciprofloxacin, and rifampicin) were prepared, respectively. These compounds were used for broad-spectrum degradation experiments according to the above-mentioned method.

[0027] The resulting BTO / GDY / Au was subjected to in vitro antibacterial experiments. BTO / GDY / Au (100 pg mL -1 ) was mixed with a fresh bacterial or fungal suspension (1 x 10 7 CFU mL -1 ) in phosphate buffered saline (PBS) (1 mL, pH = 7.3), followed by light irradiation and sonication for 5 min. The above solution was then uniformly spread on Luria-Bertani agar medium or Sabouraud dextrose agar (SDA) medium, which was incubated at 37 °C for 12 or 24 h to count the colonies.

[0028] A rapid wastewater degradation device was constructed based on the wastewater degradation capabilities of BTO / GDY / Au under light and ultrasound. The device comprises a circulating reactor, an ultrasonic generator, a light source, a mechanical stirrer, a peristaltic pump, and a filter membrane. First, the injection hose of the peristaltic pump is opened, and wastewater containing MB enters the reactor from the wastewater bottle under the action of the peristaltic pump. Then, the injection hose of the peristaltic pump is closed, and the valves at the bottom of the peristaltic pump and the bottom of the glass tube are opened, allowing the wastewater to circulate between the reactor and the glass tube. The mechanical stirrer is turned on to ensure thorough mixing of the catalyst and wastewater. The opening at the top of the reactor is used to replenish the catalyst and H2O2 while balancing the air pressure. Ultrasound is provided by the ultrasonic generator, and light is provided by the xenon lamp. After the reaction, the valve at the bottom of the glass tube is closed, and the valve at the top of the glass tube is opened. The treated wastewater flows from the top of the glass tube into a purified water bottle under the action of the peristaltic pump, while the catalyst is retained in the reaction system by the filter membrane. After completion, the injection hose of the peristaltic pump is reopened to begin the next cycle. (The initial concentration of MB is 10 ppm)

[0029]

[0030] Example 2:

[0031] Based on the above method, the amount of HEB was adjusted to synthesize BTO / GDY / Au with different GDY contents.

[0032] The catalytic performance of BTO / GDY / Au was evaluated using the MB fading model according to the method in Example 1.

[0033]

[0034] Example 3:

[0035] BTO / GDY / Au compounds with varying gold nanoparticle contents were synthesized by adjusting the amount of HAuCl4·3H2O according to the method described above. The catalytic performance of BTO / GDY / Au was evaluated using the MB fading model according to the method in Example 1.

[0036]

[0037] Example 4:

[0038] Use M W Barium titanate (BTO / GDY / Au) was synthesized using PVP with a concentration of 1,300,000, a GDY content of 8 wt%, and a gold nanoparticle content of 5 wt%. The degradation effect of different catalyst contents on methanogen (MB) was investigated. The catalytic performance of BTO / GDY / Au was evaluated according to the method described in Example 1.

[0039]

Claims

1. A method for preparing a BaTiO3 / GDY / Au piezoelectrically enhanced photocatalyst, characterized in that, The method includes the following steps: (1) First, 5 wt% of PVP of different molecular weights was dissolved in a mixed solution of ethanol, deionized water and acetic acid in a weight ratio of 5:1:

4. Then, barium acetate was added to the solution under continuous stirring. When the solution became transparent, tetrabutyl titanate was added dropwise under continuous stirring at room temperature. The stoichiometric molar ratio of Ba to Ti was 1:

1. The mixed solution was then stirred for 2 hours to form a transparent sol. The feed rate for the electrospinning process was 1.5 mL / h. -1 The voltage was 15kV, the distance between the nozzle and the collector was 15cm, the rotation speed was 60r / min, the humidity and temperature of the electrospinning chamber were 40%±5% and 25±2℃, respectively. After electrospinning, the polymer precursor was dried at 90℃ for 2 hours and then calcined at 850℃ at a heating rate of 2℃ per minute for 4 hours to obtain barium titanate. (2) GDY is mainly synthesized by coupling reaction using hexaethynylbenzene as monomer. First, a tetrahydrofuran solution of HEB-TMS and 1M tetrabutylammonium fluoride was prepared under argon atmosphere and stirred at 0°C for 15 minutes. Then, the mixture was diluted with ethyl acetate, washed twice with saturated sodium chloride solution, dried with anhydrous magnesium sulfate and filtered. Then, the solvent was evaporated under vacuum while keeping the temperature below 20°C. The resulting residue was diluted with 50 mL of acetone and added dropwise to a three-necked flask containing 100 mL of acetone, 5 mL of pyridine and 20 mg of barium titanate over 10 hours. The reaction mixture was kept under argon atmosphere at 60°C for 15 hours. All processes from deprotection to addition were carried out under dark and low temperature conditions to prevent the decomposition of HEB. After the reaction was completed, it was washed with N,N-dimethylformamide, acetone and ethanol in sequence. Finally, the barium titanate / graphyne composite material was freeze-dried. (3) Mix 10 mg barium titanate / graphyne, 26-130 μL 48.56 mM HAuCl4·3H2O and 0.5-2.5 mg sodium citrate and stir. Then, add 0.5-2.5 mg sodium borohydride to the mixture. After 10 minutes, wash the resulting material three times with deionized water and then freeze-dry it to obtain BaTiO3 / GDY / Au piezoelectric enhanced photocatalyst.

2. The application of the BaTiO3 / GDY / Au piezoelectric enhanced photocatalyst obtained by the preparation method according to claim 1 in the degradation of dyes and antibiotics, characterized in that, The BaTiO3 / GDY / Au piezoelectric enhanced photocatalyst exhibits excellent removal effects on various dyes and antibiotics in wastewater under the combined stimulation of light and ultrasound, while also possessing antibacterial activity and the ability to kill pathogens in wastewater.

3. The application of the BaTiO3 / GDY / Au piezoelectric enhanced photocatalyst obtained by the preparation method described in claim 1 in a rapid wastewater degradation device.

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