Preparation method and application of a nanoparticle heterojunction visible light catalyst

Abstract

The application discloses a kind of nanoparticle heterojunction photocatalyst Bi4V2O 11 Preparation method of Ag / AgCl: Bi (NO3) 3·5H2O, NH4VO3 and urea are dissolved in glycol aqueous solution, the pH value of the obtained mixed solution is adjusted to 8.0-10.0 with dilute ammonia water, and then transferred to a reaction kettle for hydrothermal synthesis, washed alternately with deionized water and ethanol after natural cooling, dried to obtain Bi4V2O 11 Powder; Bi4V2O 11 Powder, NaCl and AgNO3 are added into ultrapure water in sequence to stir to obtain a mixed solution, then the mixed solution is irradiated with a 300W xenon lamp for 45-60min, and the precipitate is obtained after centrifugation, and dried after washing, the obtained nanoparticle heterojunction photocatalyst can reduce the rate of photo-generated electron-hole recombination, and the preparation method is simple and the prepared catalyst has high catalytic efficiency.

Description

Technical Field

[0001] This invention belongs to the field of environmental remediation and pollution control technology, and more specifically relates to a Bi4V2O 11 Preparation method and application of / Ag / AgCl nanoparticle heterojunction photocatalyst, which is used to remove residual antibiotics in water under visible light. Background Technology

[0002] In recent years, toxic organic chemicals such as antibiotics and personal care products have been frequently detected in the aquatic environment. However, many studies have reported the frequent detection of antibiotics, especially tetracycline, in wastewater treatment plants. Due to their long-term stability and low biodegradability, these newly emerging pollutants are difficult to remove effectively using conventional wastewater treatment processes. Therefore, it is essential to find suitable water remediation technologies to effectively treat residual antibiotics in the aquatic environment.

[0003] On the one hand, photocatalysis plays a crucial role in water pollution treatment due to its advantages such as mild reaction conditions, low energy consumption, and minimal secondary pollution. However, its development is severely hampered by problems such as excessively rapid photo-generated electron-hole recombination rates and insufficient oxidation capacity. On the other hand, metal nanoparticles, acting as co-catalysts, can induce metal plasma-induced effects, thereby improving charge separation efficiency and enhancing the light absorption capacity of materials. Introducing them into photocatalysis can effectively remove recalcitrant organic pollutants. However, issues such as the instability of metal nanoparticles and metal ion dissolution exist. Therefore, coupling photocatalysis technology with metal nanoparticles can not only increase the visible light absorption range but also reduce the photo-generated electron-hole recombination rate, significantly improving the degradation performance of pollutants.

[0004] Bi4V2O is a typical Bi-based photocatalyst. 11 Bi4V2O exhibits good photocatalytic performance; however, its limited light absorption capacity and rapid recombination rate of photogenerated charges restrict its potential. 11 The widespread application of Bi4V2O, and if Bi4V2O 11 Forming a heterojunction with a semiconductor having a suitable band structure can significantly reduce the recombination efficiency of photogenerated electrons and holes, thereby improving the efficiency of Bi4V2O. 11 Its catalytic performance.

[0005] Invention application No. 202011474708.2 discloses a Bi4V2O process that is simple, efficient, and conducive to industrial production. 11 This invention utilizes a Bi4V2O heterojunction photocatalyst and applies it to the degradation of Rhodamine B, an organic pollutant. Bi4V2O is obtained via a hydrothermal method. 11BiVO4 heterojunction photocatalysts utilize visible light as a light source to degrade Rhodamine B. However, the formation of catalyst particle size is difficult to control during synthesis, leading to easy particle aggregation. This results in the recombination of photogenerated electron-hole pairs, reducing the number of active sites and decreasing catalytic efficiency.

[0006] Invention application with application number 201710290817.0 discloses a low-energy-consumption preparation method for CdS / Bi4V2O. 11 This invention describes a method for preparing heterojunction photocatalysts using a two-step solvothermal method to prepare CdS / Bi4V2O. 11 A heterojunction photocatalyst was prepared by adjusting the molar ratio of two different components to investigate its catalytic activity, demonstrating its ability to photocatalytically degrade Rhodamine B. However, the surface charge transfer efficiency of the material is not high.

[0007] Invention application with application number 202010721850.6 discloses Bi4V2O 11 / g-C3N4 heterojunction photocatalyst, its preparation method and application: This invention prepares Bi4V2O via an in-situ hydrothermal method. 11 / g-C3N4 heterojunction photocatalysts can be used for the catalytic reduction of CO2. However, the preparation method is complex and the required catalytic reduction time is relatively long. In addition, different environments have a significant impact on the activity of the catalyst; the catalyst is more prone to aggregation in aqueous environments, making its application more difficult.

[0008] Therefore, developing a metal nanoparticle heterojunction photocatalyst that is simple to prepare, can be applied to aquatic environments, can controllably prepare suitable particle sizes, can improve the photogenerated electron transfer efficiency to suppress electron-hole recombination, and thus rapidly and efficiently degrade organic pollutants is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0009] In view of this, the present invention provides a simple method that can improve Bi4V2O 11 It possesses catalytic performance while simultaneously maintaining the efficient and rapid degradation of pollutants by Bi4V2O. 11 Preparation method and application of / Ag / AgCl nanoparticle heterojunction photocatalyst.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A Bi4V2O 11 The preparation method of / Ag / AgCl nanoparticle heterojunction photocatalyst includes the following steps:

[0012] (1) Bi(NO3)3·5H2O, NH4VO3 and urea were dissolved in an aqueous solution to obtain mixed solution 1. The pH value of the obtained mixed solution 1 was adjusted to 8.0-10.0 with dilute ammonia water. Then, mixed solution 1 was transferred to a reaction vessel for hydrothermal synthesis. After natural cooling, it was washed alternately with deionized water and ethanol and dried to obtain Bi4V2O. 11 powder;

[0013] (2) The obtained Bi4V2O 11 Powder, NaCl, and AgNO3 were sequentially added to ultrapure water and stirred to obtain mixed solution 2. Mixed solution 2 was then irradiated with a 300W xenon lamp, and the precipitate was obtained by centrifugation. The precipitate was washed alternately with deionized water and ethanol, dried, and naturally cooled to obtain Bi4V2O. 11 / Ag / AgCl nanoparticle heterojunction photocatalyst.

[0014] The beneficial effects of this invention are:

[0015] 1. This invention prepares Bi4V2O by hydrothermal and photoreduction methods. 11 / Ag / AgCl nanoparticle heterojunction photocatalysts have a simple synthesis method, high internal electron transfer efficiency, and expand the visible light absorption range.

[0016] 2. The Bi4V2O of the present invention 11 The / Ag / AgCl nanoparticle heterojunction photocatalyst exhibited excellent catalytic activity during the degradation of high-concentration tetracycline solution (40 mg / L), achieving a removal efficiency of over 83% within 80 minutes.

[0017] Further, in step (1), 3.75-3.90g of Bi(NO3)3·5H2O, 0.45-0.60g of NH4VO3, and 0.75-1.00g of urea are added to every 90-100mL of the ethylene glycol aqueous solution, and the concentration of the ethylene glycol aqueous solution is 0.1-0.20mol / L.

[0018] The beneficial effects of adopting the above-mentioned further technical solutions are: increasing the adhesive force of the solution, making it easier for defects to form in the material.

[0019] Furthermore, in step (1), the concentration of the above-mentioned dilute ammonia aqueous solution is 1-3 mol / L, and the pH is adjusted to 8.0-10.0.

[0020] The beneficial effects of adopting the above-mentioned further technical solutions are: adjusting the solution pH and changing the crystal structure.

[0021] Furthermore, in step (1), the temperature of the above hydrothermal synthesis is 160-180℃, and the time of hydrothermal synthesis is 10-12h.

[0022] Furthermore, in step (1), after the above-mentioned natural cooling to below 60°C, it is washed 3-4 times alternately with deionized water and ethanol, the drying temperature is 60-80°C, and the drying time is 8-12 hours.

[0023] Furthermore, in step (2), Bi4V2O is added to every 50-60 mL of water. 11 0.30-0.45g, NaCl0.025-0.04g, AgNO30.075-0.09g.

[0024] Furthermore, in step (2), the above-mentioned Bi4V2O 11 The concentration of the solution is 0.5-0.8 g / L.

[0025] The beneficial effects of adopting the above-mentioned further technical solution are: appropriate amount of Bi4V2O 11 Doping is beneficial to Bi4V2O 11 Close contact with the AgCl interface accelerates Bi4V2O 11 Electron transport within the / Ag / AgCl nanoparticle heterostructure is improved, reducing the recombination rate of photogenerated electron-hole pairs.

[0026] Furthermore, in step (2), the irradiation time of the 300W xenon lamp is 45-60 minutes.

[0027] Furthermore, in step (2), the precipitate obtained by centrifugation is washed 3-4 times alternately with deionized water and ethanol, and dried at a temperature of 60-80℃ for 8-12 hours.

[0028] The present invention also provides the above-mentioned Bi4V2O 11 The application of / Ag / AgCl nanoparticle heterojunction photocatalysts in the degradation of antibiotics in visible light systems, including tetracycline and ciprofloxacin. Attached Figure Description

[0029] Figure 1 Bi4V2O in Example 1 11 TEM image of (a), TEM image of AgCl (b), Bi4V2O 11 TEM image (c) and HRTEM image (d) of / Ag / AgCl;

[0030] Figure 2 Using Bi4V2O in Example 2 11 and Bi4V2O 11 The removal efficiency of TC by / Ag / AgCl nanoparticle heterojunction photocatalyst;

[0031] Figure 3 Bi4V2O in Example 311 AgCl and Bi4V2O 11 XRD pattern of / Ag / AgCl;

[0032] Figure 4 Bi4V2O in Example 4 11 and Bi4V2O 11 UV-Vis diffuse reflectance absorption spectrum of / Ag / AgCl. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] Bi4V2O 11 The preparation method of / Ag / AgCl nanoparticle heterojunction photocatalyst includes the following steps:

[0036] (1) Dissolve 3.75g Bi(NO3)3·5H2O, 0.45g NH4VO3 and 0.85g urea in a 0.1mol / L ethylene glycol aqueous solution to obtain mixed solution 1. Adjust the pH of mixed solution 1 to 8.0 with 1mol / L dilute ammonia water. Then transfer mixed solution 1 to a reactor and perform hydrothermal synthesis at 160℃ for 12h. After natural cooling, wash three times alternately with deionized water and ethanol, and dry at 60℃ for 12h to obtain Bi4V2O. 11 powder;

[0037] (2) Add 0.30g Bi4V2O 11 Powder, 0.025 g NaCl, and 0.075 g AgNO3 were sequentially added to ultrapure water and stirred to obtain mixed solution 2. Mixed solution 2 was then irradiated with a 300 W xenon lamp for 45 min. After centrifugation, the precipitate was washed three times alternately with deionized water and ethanol, and dried at 60 °C for 12 h to obtain Bi4V2O. 11 / Ag / AgCl nanoparticle heterojunction photocatalyst.

[0038] Bi4V2O prepared in step (1) 11 Powder and Bi4V2O prepared in step (2) 11 The / Ag / AgCl nanoparticle heterojunction photocatalyst was characterized by TEM, and by Figure 1 It can be seen that the prepared Bi4V2O 11The powder has a spherical structure composed of nanosheets; AgCl has a nanosheet structure; Bi4V2O 11 Bi₄V₂O can be clearly observed in the / Ag / AgCl composite material. 11 The lattice spacing is 0.312 nm. The ultrathin two-dimensional heterostructure is beneficial for accelerating the formation of Bi4V2O. 11 Electron transport within the / Ag / AgCl heterojunction reduces the photogenerated electron-hole recombination rate.

[0039] Example 2

[0040] Bi4V2O 11 The preparation method of / Ag / AgCl nanoparticle heterojunction photocatalyst includes the following steps:

[0041] (1) 3.80 g Bi(NO3)3·5H2O, 0.50 g NH4VO3 and 0.90 g urea were dissolved in a 0.13 mol / L ethylene glycol aqueous solution to obtain mixed solution 1. The pH value of the obtained mixed solution 1 was adjusted to 9.0 with a 2 mol / L dilute ammonia solution. Mixed solution 1 was then transferred to a reaction vessel and hydrothermally synthesized at 170℃ for 11 h. After natural cooling, it was washed three times alternately with deionized water and ethanol, and dried at 70℃ for 10 h to obtain Bi4V2O. 11 powder;

[0042] (2) Add 0.35g Bi4V2O 11 Powder, 0.030 g NaCl, and 0.080 g AgNO3 were sequentially added to ultrapure water and stirred to obtain mixed solution 2. Mixed solution 2 was then irradiated with a 300 W xenon lamp for 50 min. After centrifugation, the precipitate was washed three times alternately with deionized water and ethanol, and dried at 70 °C for 10 h to obtain Bi4V2O. 11 / Ag / AgCl nanoparticle heterojunction photocatalyst.

[0043] The Bi4V2O prepared in step (2) 11 / Ag / AgCl nanoparticle heterojunction photocatalyst was used to degrade tetracycline (TC). 50 mL of a 40 mg / L TC solution was prepared and placed in the photoreactor, along with 20 mg of Bi₄V₂O. 11 Ag / AgCl nanoparticles were reacted in the dark for 30 minutes to reach adsorption equilibrium. A 300W xenon lamp was used to simulate visible light, and the remaining TC concentration was measured every 5 minutes after the lamp was turned on. The TC degradation effect under visible light conditions within 80 minutes was as follows: Figure 2 As shown. Compared to Bi4V2O 11 ,Bi4V2O 11 / Ag / AgCl photocatalytic materials show significantly improved degradation performance, achieving a degradation rate of 83% for TC, while Bi4V2O11 The degradation rate was only 21%. These results indicate that Bi4V2O 11 / Ag / AgCl nanoparticle heterojunction photocatalysts have excellent degradation capabilities and can rapidly and efficiently degrade pollutants.

[0044] Example 3

[0045] Bi4V2O 11 The preparation method of / Ag / AgCl nanoparticle heterojunction photocatalyst includes the following steps:

[0046] (1) Dissolve 3.85g Bi(NO3)3·5H2O, 0.55g NH4VO3 and 0.95g urea in a 0.15mol / L ethylene glycol aqueous solution to obtain mixed solution 1. Adjust the pH of the obtained mixed solution 1 to 9.5 with a 2mol / L dilute ammonia solution. Then transfer mixed solution 1 to a reactor and perform hydrothermal synthesis at 170℃ for 11h. After natural cooling, wash three times alternately with deionized water and ethanol, and dry at 70℃ for 10h to obtain Bi4V2O. 11 powder;

[0047] (2) Add 0.40g Bi4V2O 11 Powder, 0.035 g NaCl, and 0.085 g AgNO3 were sequentially added to ultrapure water and stirred to obtain mixed solution 2. Mixed solution 2 was then irradiated with a 300 W xenon lamp for 55 min. After centrifugation, the precipitate was washed three times alternately with deionized water and ethanol, and dried at 70 °C for 10 h to obtain Bi4V2O. 11 / Ag / AgCl nanoparticle heterojunction photocatalyst.

[0048] Bi4V2O prepared in step (1) 11 Powder and Bi4V2O prepared in step (2) 11 The / Ag / AgCl nanoparticle heterojunction photocatalyst was characterized by XRD. Figure 3 It can be seen that Bi4V2O 11 All peak values ​​were consistent with the standard card (JCPDS No. 42-0135), indicating that Bi4V2O 11 Nanomaterials have been successfully prepared, specifically for Bi4V2O. 11 The presence of distinct AgCl characteristic diffraction peaks at 2θ = 27.8°, 57.5°, and 67.6° indicates the successful introduction of AgCl into Bi₄V₂O. 11 middle.

[0049] Example 4

[0050] Bi4V2O 11The preparation method of / Ag / AgCl nanoparticle heterojunction photocatalyst includes the following steps:

[0051] (1) 3.90 g Bi(NO3)3·5H2O, 0.60 g NH4VO3 and 1.0 g urea were dissolved in a 0.20 mol / L ethylene glycol aqueous solution to obtain mixed solution 1. The pH value of the obtained mixed solution 1 was adjusted to 10.0 with a 3 mol / L dilute ammonia solution. Mixed solution 1 was then transferred to a reaction vessel and hydrothermally synthesized at 180℃ for 10 h. After natural cooling, it was washed three times alternately with deionized water and ethanol, and dried at 80℃ for 8 h to obtain Bi4V2O. 11 powder;

[0052] (2) Add 0.45g Bi4V2O 11 Powder, 0.040 g NaCl, and 0.090 g AgNO3 were sequentially added to ultrapure water and stirred to obtain mixed solution 2. Mixed solution 2 was then irradiated with a 300 W xenon lamp for 60 min. After centrifugation, the precipitate was washed three times alternately with deionized water and ethanol, and dried at 80 °C for 8 h to obtain Bi4V2O. 11 / Ag / AgCl nanoparticle heterojunction photocatalyst.

[0053] Bi4V2O prepared in step (1) 11 Powder and Bi4V2O prepared in step (2) 11 The UV-Vis diffuse reflectance absorption spectrum of the / Ag / AgCl nanoparticle heterojunction photocatalyst is shown below. Figure 4 As shown. With Bi4V2O 11 Compared to Bi4V2O 11 / Ag / AgCl nanoparticle heterojunction photocatalysts have better light absorption capabilities.

Claims

1. A Bi4V2O 11 The method for preparing Ag / AgCl nanoparticle heterojunction photocatalysts is characterized by, Includes the following steps: (1) Bi(NO3)3·5H2O, NH4VO3 and urea were dissolved in an aqueous ethylene glycol solution to obtain mixed solution 1. The pH value of the obtained mixed solution 1 was adjusted to 8.0-10.0 with dilute ammonia water. Then, mixed solution 1 was transferred to a reactor for hydrothermal synthesis. After natural cooling, it was washed alternately with deionized water and ethanol and dried to obtain Bi4V2O. 11 powder; (2) The obtained Bi4V2O 11 Powder, NaCl, and AgNO3 were sequentially added to ultrapure water and stirred to obtain mixed solution 2. Mixed solution 2 was then irradiated with a 300W xenon lamp. After centrifugation, the precipitate was washed alternately with deionized water and ethanol, dried, and naturally cooled to obtain Bi4V2O. 11 / Ag / AgCl nanoparticle heterojunction photocatalyst; Bi4V2O 11 The Ag / AgCl nanoparticle heterojunction photocatalyst has a particle size of 3-10 nm, in which Ag / AgCl accounts for 15-35% of the total catalyst weight, and the remainder is Bi4V2O. 11 .

2. The Bi4V2O according to claim 1 11 The method for preparing Ag / AgCl nanoparticle heterojunction photocatalysts is characterized by, In step (1), the concentration of the dilute ammonia solution is 1-3 mol / L, and the pH is adjusted to 8.0-10.

0.

3. The Bi4V2O according to claim 1 11 The method for preparing Ag / AgCl nanoparticle heterojunction photocatalysts is characterized by, In step (2), the 300 W xenon lamp irradiation time is 45-60 min.

4. A Bi4V2O as described in any one of claims 1-3 11 Bi4V2O prepared by the method of preparing / Ag / AgCl nanoparticle heterojunction photocatalyst 11 The application of / Ag / AgCl nanoparticle heterojunction photocatalysts in the degradation of organic pollutants is characterized by... The organic pollutant is tetracycline or ciprofloxacin.

Images