A phosphorus-vanadium co-doped bismuth oxychloride with enhanced built-in electric field, and a preparation method and application thereof

Abstract

The application relates to a built-in electric field enhanced phosphorus-vanadium co-doped bismuth oxychloride as well as a preparation method and application thereof. Bismuth nitrate pentahydrate and sodium hypophosphite monohydrate are dissolved in ethylene glycol to obtain solution A; potassium chloride and ammonium metavanadate are dissolved in water to obtain solution B; solution B is added drop by drop into the stirring solution A, and after fully stirring and reacting at room temperature, a hydrothermal reaction is carried out, so as to uniformly and effectively improve the IEF of the BiOCl material and improve the specific effect of the photocatalytic performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photocatalysis, and particularly relates to a phosphorus-vanadium co-doped bismuth oxychloride with enhanced built-in electric field and a preparation method and application thereof. BACKGROUND

[0002] The built-in electric field (IEF) plays a crucial role in the photocatalytic process. IEF can effectively promote the separation of photo-generated carriers (electrons and holes), significantly improving the efficiency of photocatalytic reactions. Correctly understanding and enhancing IEF can greatly improve the photocatalytic performance of semiconductor materials because IEF not only reduces the recombination of electron-hole pairs, but also guides the migration of carriers to the surface active sites, thereby accelerating the photocatalytic reaction. Although the importance of IEF has been widely recognized, how to effectively control and enhance IEF through material design, especially in semiconductor materials with complex structure and electronic properties, remains a challenge. The strength of IEF directly affects the separation efficiency of carriers, and thus the activity of photocatalysts. Adjusting the electronic structure of semiconductor materials to enhance IEF has been proven to be an effective way to improve photocatalytic performance. In this context, doping strategies have been widely studied and applied, aiming to adjust the electronic structure and surface properties of semiconductors by introducing foreign atoms or ions. Although the doping strategy has great potential in theory, it also faces the problem that the IEF strength is limited only from certain crystal faces or atomic layers.

[0003] Therefore, focusing on exploring a new non-metal-metal co-doping strategy that can uniformly and effectively enhance IEF is crucial for improving the performance of photocatalysts. SUMMARY

[0004] The purpose of the present application is to provide a preparation method of phosphorus-vanadium co-doped bismuth oxychloride with enhanced built-in electric field, aiming to uniformly and effectively enhance the IEF of BiOCl material by precisely controlling the types and proportions of doping elements, and to reveal the influence mechanism of co-doping on the electronic structure of BiOCl and its specific improvement effect on photocatalytic performance through theoretical calculation and experimental verification.

[0005] The purpose of the present application is achieved by the following technical solutions:

[0006] A preparation method of phosphorus-vanadium co-doped bismuth oxychloride with enhanced built-in electric field, specifically comprising the following steps:

[0007] Dissolve bismuth nitrate pentahydrate and sodium hypophosphite monohydrate in ethylene glycol to obtain solution A;

[0008] Dissolve potassium chloride and ammonium metavanadate in water to obtain solution B;

[0009] Solution B is added dropwise to the stirring solution A, and after the reaction is fully stirred at room temperature, a hydrothermal reaction is performed.

[0010] Further, the mass ratio of the bismuth nitrate pentahydrate, sodium hypophosphite monohydrate and ammonium metavanadate is 281.44: (2.47-4.3): 1.

[0011] Further, the mass ratio of the potassium chloride and ammonium metavanadate is 41.63: 1.

[0012] Further, the volume ratio of the ethylene glycol and water is (5-2):(1-3). Still further, the ratio of the ethylene glycol and water is 4:1.

[0013] Further, the hydrothermal reaction time is 3-24h.

[0014] Further, the hydrothermal reaction pressure is 1-2MPa.

[0015] Further, the pH is adjusted to 1.5-3.5 after solution B is added dropwise to the stirring solution A. Still further, the pH is adjusted to 2.5.

[0016] The application also aims to provide the application of the enhanced built-in electric field phosphorus-vanadium co-doped bismuth oxychloride as a photocatalyst in removing organic pollutants in water.

[0017] As a more preferred technical solution of the application, the organic pollutants include one or more of ciprofloxacin, ofloxacin, levofloxacin, norfloxacin, moxifloxacin, gatifloxacin, marbofloxacin and tetracycline hydrochloride. More preferably, ciprofloxacin is removed, and the dosage is 0.05-0.4g / L.

[0018] Compared with the prior art, the photocatalyst can achieve the following beneficial effects:

[0019] The photocatalyst preparation method provided by the application has the advantages of simple operation, environmental friendliness and good repeatability, and provides method support for subsequent long-term large-scale preparation of photocatalytic materials for efficient treatment of complex pharmaceutical wastewater.

[0020] The application uses phosphorus-vanadium co-doping to enhance the built-in electric field of bismuth oxychloride, and evaluates the performance of phosphorus-vanadium co-doped BiOCl in treating refractory organic pollutants in water. It can selectively remove strong hydrophilic pollutants from complex wastewater, and has good anti-interference performance on anions (HCO3 − , NO3 − and Cl − ) and water matrix (tap water and secondary effluent, etc.), providing a new strategy for developing efficient and stable photocatalysts. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application, illustrate preferred embodiments of the application, and assist in explaining the application. In the drawings:

[0022] Figure 1 SEM morphology characterization images of Comparative Example 1 and Example 2, where a is SEM morphology characterization of Comparative Example 1, b is SEM morphology characterization of Example 2, and c is high resolution transmission electron microscopy (HRTEM) image of Example 2;

[0023] Figure 2 X-ray diffraction (XRD) patterns of Comparative Examples 1-3 and Example 2;

[0024] Figure 3 Fourier transform infrared (FT-IR) spectra of Comparative Examples 1-3 and Example 2;

[0025] Figure 4 X-ray photoelectron spectroscopy (XPS) of Comparative Examples 1-3 and Example 2;

[0026] Figure 5 Nitrogen adsorption desorption curves (BET) of Comparative Examples 1-3 and Example 2 for calculation of specific surface area;

[0027] Figure 6 Ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) of Comparative Examples 1-3 and Example 2;

[0028] Figure 7 IEF test of Comparative Examples 1-3 and Example 2;

[0029] Figure 8 Efficiency of removal of ciprofloxacin of Comparative Examples 1-3 and Example 2;

[0030] Figure 9 Efficiency of removal of ciprofloxacin of Examples 1-4;

[0031] Figure 10 Efficiency of removal of ciprofloxacin of Examples 5-8;

[0032] Figure 11 Efficiency of removal of CIP of Examples 9-11;

[0033] Figure 12 Efficiency of removal of CIP of Examples 12-14;

[0034] Figure 13 Efficiency of removal of CIP of Examples 15-17;

[0035] Figure 14 Efficiency of BOC-PV of Example 2 in removing various other organic pollutants;

[0036] Figure 15 Efficiency of BOC-PV of Example 2 in removing ciprofloxacin in the presence of different anions;

[0037] Figure 16 Efficiency of BOC-PV of Example 2 in removing ciprofloxacin in different actual water matrix conditions;

[0038] Figure 17 Identification of the main active species of BOC-PV of Example 2 in removing ciprofloxacin;

[0039] Figure 18 Efficiency of BOC-PV of Example 2 in removing ciprofloxacin in a cycle;

[0040] Figure 19 XRD patterns of BOC-PV of Example 2 before and after removal. DETAILED DESCRIPTION

[0041] The application will be further described in conjunction with the specific embodiments, and the examples given are only to illustrate the application, and are not intended to limit the scope of the application. The examples provided below can serve as a guide for further improvement by those of ordinary skill in the art, and do not in any way constitute a limitation on the application. It should be noted that the examples in the present application and the features in the examples can be combined with each other without conflict.

[0042] The experimental methods in the following examples are all conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples are all conventional biochemical reagents unless otherwise specified, which can be obtained commercially. The room temperature in the following examples is 30°C. The hydrothermal reaction is carried out in a 100 mL sealed reaction kettle, the pressure is 1.5 Mpa, and the dropping speed is 2 s per drop. Slow dropping will make the material fully react. The molar concentration of bismuth nitrate pentahydrate in solution A is 0.09 mol / L-0.1 mol / L. The molar concentration of potassium chloride in solution B is 0.4 mol / L-0.5 mol / L. Sodium hydroxide is used for pH adjustment. The total amount of ethylene glycol and water used in solution A and solution B is 50 mL.

[0043] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the examples.

[0044] Comparative Example 1

[0045] Bismuth nitrate pentahydrate 1.9701 g was dissolved in 40 mL of ethylene glycol to obtain solution A, and potassium chloride 0.2914 g was dissolved in 10 mL of water to obtain solution B. Solution B was added dropwise into the stirring solution A, and the pH was adjusted to 2.5. After the reaction was fully stirred at room temperature, a hydrothermal reaction was performed at 180°C for 12 h, and the product was recorded as BOC.

[0046] Comparative Example 2

[0047] Bismuth nitrate pentahydrate 1.9701 g and sodium hypophosphite monohydrate 0.0214 g were dissolved in 40 mL of ethylene glycol to obtain solution A, and potassium chloride 0.2914 g was dissolved in 10 mL of water to obtain solution B. Solution B was added dropwise into the stirring solution A, and the pH was adjusted to 2.5. After the reaction was fully stirred at room temperature, a hydrothermal reaction was performed at 180°C for 6 h, and the product was recorded as BOC-P.

[0048] Comparative Example 3

[0049] Bismuth nitrate pentahydrate 1.9701 g was dissolved in 40 mL of ethylene glycol to obtain solution A, and potassium chloride 0.2914 g and ammonium metavanadate 0.0070 g were dissolved in 10 mL of water to obtain solution B. Solution B was added dropwise into the stirring solution A, and the pH was adjusted to 2.5. After the reaction was fully stirred at room temperature, a hydrothermal reaction was performed at 180°C for 6 h, and the product was recorded as BOC-V.

[0050] Example 1

[0051] Bismuth nitrate pentahydrate 1.9701 g and sodium hypophosphite monohydrate 0.0214 g were dissolved in 40 mL of ethylene glycol to obtain solution A, and potassium chloride 0.2914 g and ammonium metavanadate 0.0070 g were dissolved in 10 mL of water to obtain solution B. Solution B was added dropwise into the stirring solution A, and the pH was adjusted to 2.5. After the reaction was fully stirred at room temperature, a hydrothermal reaction was performed at 180°C for 3 h, and the product was recorded as BOC-PV-3h.

[0052] Example 2

[0053] Bismuth nitrate pentahydrate 1.9701 g and sodium hypophosphite monohydrate 0.0214 g were dissolved in 40 mL of ethylene glycol to obtain solution A, and potassium chloride 0.2914 g and ammonium metavanadate 0.0070 g were dissolved in 10 mL of water to obtain solution B. Solution B was added dropwise into the stirring solution A, and the pH was adjusted to 2.5. After the reaction was fully stirred at room temperature, a hydrothermal reaction was performed at 180°C for 6 h, and the product was recorded as BOC-PV.

[0054] Example 3

[0055] Bismuth nitrate pentahydrate 1.9701 g and sodium hypophosphite monohydrate 0.0214 g were dissolved in 40 mL of ethylene glycol to obtain solution A, potassium chloride 0.2914 g and ammonium metavanadate 0.0070 g were dissolved in 10 mL of water to obtain solution B, solution B was added dropwise into the stirring solution A, and the pH was adjusted to 2.5. After the reaction was fully stirred at room temperature, a hydrothermal reaction was carried out at 180°C for 12 h, and was recorded as BOC-PV-12h.

[0056] Example 4

[0057] Bismuth nitrate pentahydrate 1.9701 g and sodium hypophosphite monohydrate 0.0214 g were dissolved in 40 mL of ethylene glycol to obtain solution A, potassium chloride 0.2914 g and ammonium metavanadate 0.0070 g were dissolved in 10 mL of water to obtain solution B, solution B was added dropwise into the stirring solution A, and the pH was adjusted to 2.5. After the reaction was fully stirred at room temperature, a hydrothermal reaction was carried out at 180°C for 24 h, and was recorded as BOC-PV-24h.

[0058] Example 5

[0059] Bismuth nitrate pentahydrate 1.9701 g and sodium hypophosphite monohydrate 0.0214 g were dissolved in 41.67 mL of ethylene glycol to obtain solution A, potassium chloride 0.2914 g and ammonium metavanadate 0.0070 g were dissolved in 8.33 mL of water to obtain solution B, solution B was added dropwise into the stirring solution A, and the pH was adjusted to 2.5. After the reaction was fully stirred at room temperature, a hydrothermal reaction was carried out at 180°C for 6 h, and was recorded as BOC-PV-5:1.

[0060] Example 6

[0061] Bismuth nitrate pentahydrate 1.9701 g and sodium hypophosphite monohydrate 0.0214 g were dissolved in 40 mL of ethylene glycol to obtain solution A, potassium chloride 0.2914 g and ammonium metavanadate 0.0070 g were dissolved in 10 mL of water to obtain solution B, solution B was added dropwise into the stirring solution A, and the pH was adjusted to 2.5. After the reaction was fully stirred at room temperature, a hydrothermal reaction was carried out at 180°C for 6 h, and was recorded as BOC-PV-4:1.

[0062] Example 7

[0063] Bismuth nitrate pentahydrate 1.9701 g and sodium hypophosphite monohydrate 0.0214 g were dissolved in 30 mL of ethylene glycol to obtain solution A, potassium chloride 0.2914 g and ammonium metavanadate 0.0070 g were dissolved in 20 mL of water to obtain solution B, solution B was added dropwise into the stirring solution A, and the pH was adjusted to 2.5. After the reaction was fully stirred at room temperature, a hydrothermal reaction was carried out at 180°C for 6 h, and was recorded as BOC-PV-3:2.

[0064] Example 8

[0065] BOC-PV-2:3

[0066] Example 9

[0067] BOC-PV-P-4.1

[0068] Example 10

[0069] BOC-PV-P-6.1

[0070] Example 11

[0071] BOC-PV-P-7.1

[0072] Example 12

[0073] BOC-PV-V-10

[0074] Example 13

[0075] Solution A was prepared by dissolving 1.9701 g of bismuth nitrate pentahydrate and 0.0214 g of sodium hypophosphite monohydrate in 40 mL of ethylene glycol. Solution B was prepared by dissolving 0.2914 g of potassium chloride and 0.0080 g of ammonium metavanadate in 10 mL of water. Solution B was added dropwise to solution A while it was being stirred, and the pH was adjusted to 2.5. After stirring thoroughly at room temperature, the reaction was carried out hydrothermally at 180 °C for 6 hours, and this reaction was denoted as BOC-PV-V-17.

[0076] Example 14

[0077] Solution A was prepared by dissolving 1.9701 g of bismuth nitrate pentahydrate and 0.0214 g of sodium hypophosphite monohydrate in 40 mL of ethylene glycol. Solution B was prepared by dissolving 0.2914 g of potassium chloride and 0.0094 g of ammonium metavanadate in 10 mL of water. Solution B was added dropwise to solution A while it was being stirred, and the pH was adjusted to 2.5. After stirring thoroughly at room temperature, the reaction was carried out hydrothermally at 180 °C for 6 hours, and this solution was denoted as BOC-PV-V-20.

[0078] Example 15

[0079] Solution A was prepared by dissolving 1.9701 g of bismuth nitrate pentahydrate and 0.0214 g of sodium hypophosphite monohydrate in 40 mL of ethylene glycol. Solution B was prepared by dissolving 0.2914 g of potassium chloride and 0.0070 g of ammonium metavanadate in 10 mL of water. Solution B was added dropwise to solution A while it was being stirred, without adjusting the pH. After stirring thoroughly at room temperature, a hydrothermal reaction was carried out at 180 °C for 6 hours, denoted as BOC-PV-no pH adjustment.

[0080] Example 16

[0081] Solution A was prepared by dissolving 1.9701 g of bismuth nitrate pentahydrate and 0.0214 g of sodium hypophosphite monohydrate in 40 mL of ethylene glycol. Solution B was prepared by dissolving 0.2914 g of potassium chloride and 0.0070 g of ammonium metavanadate in 10 mL of water. Solution B was added dropwise to solution A while it was being stirred, and the pH was adjusted to 1.5. After stirring thoroughly at room temperature, the reaction was carried out hydrothermally at 180 °C for 6 hours, and the result was recorded as BOC-PV-pH=1.5.

[0082] Example 17

[0083] Solution A was prepared by dissolving 1.9701 g of bismuth nitrate pentahydrate and 0.0214 g of sodium hypophosphite monohydrate in 40 mL of ethylene glycol. Solution B was prepared by dissolving 0.2914 g of potassium chloride and 0.0070 g of ammonium metavanadate in 10 mL of water. Solution B was added dropwise to solution A while it was being stirred, and the pH was adjusted to 3.5. After stirring thoroughly at room temperature, the reaction was carried out hydrothermally at 180 °C for 6 hours, and the result was recorded as BOC-PV-pH=3.5.

[0084] Example 18

[0085] Solution A was prepared by dissolving 1.9701 g of bismuth nitrate pentahydrate and 0.0214 g of sodium hypophosphite monohydrate in 40 mL of ethylene glycol, and solution B was prepared by dissolving 0.2914 g of potassium chloride and 0.0070 g of ammonium metavanadate in 10 mL of water. Solution B was added dropwise to solution A under stirring, and the pH was adjusted to 2.5. After the reaction was fully stirred at room temperature, a hydrothermal reaction was performed at 180 °C and a pressure of 2 Mpa for 6 h, and the product was denoted as BOC-PV-2M.

[0086] Example 19

[0087] Solution A was prepared by dissolving 1.9701 g of bismuth nitrate pentahydrate and 0.0214 g of sodium hypophosphite monohydrate in 40 mL of ethylene glycol, and solution B was prepared by dissolving 0.2914 g of potassium chloride and 0.0070 g of ammonium metavanadate in 10 mL of water. Solution B was added dropwise to solution A under stirring, and the pH was adjusted to 2.5. After the reaction was fully stirred at room temperature, a hydrothermal reaction was performed at 180 °C and a pressure of 2 Mpa for 6 h, and the product was denoted as BOC-PV-2M.

[0088] By Figure 1 SEM morphology characterization of Comparative Example 1 of a and Example 2 of b, it can be seen that the BOC of Comparative Example 1 and the BOC-PV of Example 2 are both ultra-thin nanosheet structures. Figure 1 HRTEM image of Example 2 of c, the insert shows that the BOC-PV of Example 2 exhibits crystal lattice diffraction fringes corresponding to (101) and (110) planes, respectively, and the fringe spacings are 0.345 nm and 0.275 nm, respectively. Ethylene glycol provides viscosity for the reaction of substances in the solvent.

[0089] XRD comparison of Comparative Examples 1 to 3 and Example 2 is shown in Figure 2 , it can be seen that the diffraction peaks at 25.8 and 32.5° correspond to the (101) and (110) crystal planes of PVP / CN of Comparative Example 1, respectively. With the doping of P and V, the peak positions of the diffraction peaks are slightly shifted, as shown in Figure 1 . Taking the (110) plane as an example, compared with the BOC of Comparative Example 1, the peak position of the BOC-P of Comparative Example 2 moves to the left after P doping, and the peak position of the BOC-V of Comparative Example 3 moves to the right after V doping, which indicates the successful doping of P and V.

[0090] FT-IR comparison of Comparative Examples 1 to 3 and Example 2 is shown in Figure 3 . Comparative Examples 1 to 3 and Example 2 all exhibit three infrared absorption peaks. The infrared absorption peak at 530 cm -1The peak values ​​are caused by Bi-O bond vibrations. At 1620 and 3440 cm⁻¹... -1 The nearby vibrational bands were identified as bending and stretching vibrations of adsorbed water and hydroxyl groups. A new characteristic peak appeared at 960 cm⁻¹ for both BOC-P and BOC-PV. -1 At this location, it is related to the tensile vibration of the PO bond.

[0091] XPS comparison between Examples 1 to 3 and Example 2 Figure 4 As shown in the figure. Figures a and b represent Bi4f XPS and Cl2p XPS from Example 1, respectively. The binding energies at 164.68 and 159.38 eV correspond to Bi4f7 / 2 and Bi4f5 / 2, respectively, confirming that Bi... 3+ The presence of . The two strong peaks at approximately 197.6 and 199.2 eV are attributed to Cl 2p 3 / 2 and Cl 2p 1 / 2, indicating the successful synthesis of BiOCl.

[0092] Comparing Test N of Examples 1 to 3 and Example 2 2 Adsorption-desorption curves are as follows Figure 5 As shown, the specific surface areas (SSA) of the BOC, BOC-P, BOC-V, and BOC-PV samples were obtained. According to the IUPAC standard, all exhibited typical Type IV isotherms. The specific surface areas of BOC, BOC-P, BOC-V, and BOV-PV were 12.10, 31.82, 24.06, and 55.96 m², respectively. 2 / g. The above results show that P and V doping increases the specific surface area.

[0093] Comparing the UV-Vis diffuse reflectance spectra (UV-visDRS) of Examples 1 to 3 and Example 2, for example... Figure 6 As shown, the position of the absorption band edge did not change significantly. The results indicate that P and V doping has limited effect on improving light absorption.

[0094] Comparison of IEF intensity between Examples 1 to 3 and Example 2 Figure 7 As shown. The built-in electric field strengths of Comparative Examples 2-3 and Example 2 are 3.9, 6.2, and 17.7, respectively (the strength of BOC in Comparative Example 1 is set to 1). The results show that P and V doping effectively improves the built-in electric field strength, and PV co-doping can synergistically improve the built-in electric field strength.

[0095] Application Example 1

[0096] Comparative Examples 1 to 3 and Examples 1 to 9: Application of Ciprofloxacin Removal

[0097] Firstly, 0.001 g of Comparative Example 1 to 3 and Example 2 catalysts were put into 70 mL of ciprofloxacin aqueous solution (CIP, 10 mg / L). Then, the stirring was started and the reaction was activated by visible light. The visible light was provided by a 300.0 W xenon lamp (CEL-HXF300, Beijing Zhongjiao Jin Yuan Technology Co., Ltd.) with a wavelength less than 420 nm filter. The light intensity was 122.9 mW / cm 2 (Illumination area = 3.34 cm 2 ). During the reaction, 1.0 mL of sample was collected every 15 minutes and filtered by a 0.22 μm filter membrane. The concentration of ciprofloxacin was detected by the Thermo high performance liquid chromatography. As shown in Figure 8 , the degradation rate of BOC in Example 2 was increased to 90%, indicating that the built-in electric field improved by the phosphorus-vanadium co-doping strategy can effectively improve the photocatalytic ability.

[0098] The efficiency of Examples 1 to 4 in removing CIP is shown in Figure 9 . Compared with BOC-PV-24h of Example 1 (77.32%), BOC-PV-12h of Example 2 (79.77%), BOC-PV-3h of Example 4 (84.53%), and BOC-PV-12h of Example 3, the efficiency of removing CIP reached 90%.

[0099] The efficiency of Examples 5 to 8 in removing CIP is shown in Figure 10 . Compared with BOC-PV-5:1 of Example 5 (85.62%), BOC-PV-3:2 of Example 7 (80.81%), BOC-PV-2:3 of Example 8 (75.82%), and BOC-PV-4:1 of Example 6, the efficiency of removing CIP reached 90%.

[0100] The efficiency of Examples 9 to 11 in removing CIP is shown in Figure 11 . Compared with BOC-PV-P-4.1 of Example 9 (66.74%), BOC-PV-P-6.1 of Example 10 (75.62%), BOC-PV-P-7.1 of Example 11 (71.88%), and BOC-PV of Example 2, the efficiency of removing CIP reached 90%.

[0101] The efficiency of Examples 12 to 14 in removing CIP is shown in Figure 12 . Compared with BOC-PV-V-10 of Example 12 (70.02%), BOC-PV-V-17 of Example 13 (72.32%), BOC-PV-V-20 of Example 14 (68.15%), and BOC-PV of Example 2, the efficiency of removing CIP reached 90%.

[0102] The removal efficiency of CIP of Example 15 to 17 is shown in Figure 13 Compared with BOC-PV-no pH adjustment of Example 15 (62.34%), BOC-PV-pH=1.5 of Example 16 (72.08%), BOC-PV-pH=3.5 of Example 17 (73.36%), the removal efficiency of CIP of BOC-PV of Example 2 reached 90%.

[0103] Application of Example 2

[0104] Application of BOC-PV of Example 2 in removing different organic pollutants

[0105] Firstly, 0.001 g catalyst of Example 1 to 4 was respectively put into 70 mL aqueous solution containing ofloxacin (OFL, 10 mg / L), levofloxacin (LVFX, 10 mg / L), norfloxacin (NOR, 10 mg / L), moxifloxacin (MOX, 10 mg / L), gatifloxacin (GAT, 10 mg / L), marbofloxacin (MAR, 10 mg / L). Then, stirring was started and the reaction was activated by visible light. The visible light was provided by a 300.0 W xenon lamp (CEL-HXF300, Beijing Zhongjiao Jin Yuan Technology Co., Ltd.) with a wavelength less than 420 nm filter. The light intensity was 122.9 mW / cm 2 (Illumination area = 3.34 cm 2 ). During the reaction, 1.0 mL sample was collected every 15 minutes and filtered by 0.22 μm filter membrane. The concentration of different organic pollutants was detected by the high performance liquid chromatography of Thermo. As shown in Figure 14 The results showed that BOC-PV could complete efficient degradation of various organic pollutants.

[0106] Application of Example 3

[0107] Environmental factor interference experiment of BOC-PV of Example 2

[0108] The removal efficiency of CIP of BOC-PV of Example 2 under different anion conditions is shown in Figure 15 The removal efficiency of CIP of BOC-PV of Example 2 in the presence of C − , NO3 − and HCO3 − reached 89.0, 85.3, 89.3%, respectively. The results showed that the removal efficiency of CIP under anion conditions did not change significantly.

[0109] The removal efficiency of CIP of BOC-PV of Example 2 under different actual water matrix conditions is shown in Figure 16The removal efficiency of BOC-PV of Example 2 in tap water CIP is basically unchanged compared with the removal efficiency (89%) in deionized water CIP, while the removal rate of CIP in secondary effluent is reduced to 65.2%, and the slight decrease in removal rate in secondary effluent indicates that the organic pollutants contained in the water matrix may become the attack site of active species. The above shows that the BOC-PV based on Example 2 has certain anti-interference performance.

[0110] Application Example 4

[0111] Main active species of BOC-PV of Example 2 in the process of removing CIP

[0112] The identification results of the main active species of BOC-PV of Example 2 in removing CIP are as shown in Figure 17 All detected active species contribute to the degradation of pollutants except e-, and the contribution size order is:•O 2− > 1 O2>h + >•OH. It is shown that the enhancement of IEF effectively promotes the separation of photo-generated carriers, thereby promoting the generation of multiple active species and improving the photocatalytic degradation.

[0113] Application Example 5

[0114] Application of BOC-PV of Example 2 in the cycle removal of CIP

[0115] First, 0.001 g of catalysts of Examples 1 to 4 was placed in 70 mL of ciprofloxacin aqueous solution (CIP, 10 mg / L). Then, stirring was started and the reaction was activated with visible light. The visible light was provided by a 300.0 W xenon lamp (CEL-HXF300, Beijing Zhongjiao Jin Yuan Technology Co., Ltd.) with a wavelength less than 420 nm filter. The light intensity was 122.9 mW / cm 2 (Illumination area = 3.34 cm 2 ). During the reaction, 1.0 mL of sample was collected every 15 minutes and filtered through a 0.22 μm filter membrane. After 1 h of reaction, the sample was centrifuged and dried for the next removal. In this way, the cycle was repeated 4 times, and the concentration of ciprofloxacin was detected by the Thermo high performance liquid chromatography. The cycle removal efficiency of CIP of BOC-PV of Example 2 is as shown in Figure 18 After four cycles, the degradation efficiency of CIP of BOC-PV of Example 2 only decreased by 5.4%. The results show that BOC-PV of Example 2 has good cycle performance.

[0116] The XRD patterns of BOC-PV of Example 2 before and after reaction are as shown in Figure 19The XRD patterns of the BOC-PV of Example 2 before and after the reaction did not change substantially, indicating that the BOC-PV of Example 2 has a stable phase structure.

[0117] The above detailed description does not constitute a limitation on the protection scope of the present application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a built-in electric field enhanced phosphorus-vanadium co-doped bismuth oxychloride, characterized in that, The preparation method comprises the following steps: dissolving bismuth nitrate pentahydrate and sodium hypophosphite monohydrate in ethylene glycol to obtain solution A; dissolving potassium chloride and ammonium metavanadate in water to obtain solution B; adding solution B into solution A drop by drop under stirring, fully stirring and reacting at room temperature, and then performing hydrothermal reaction; the mass ratio of bismuth nitrate pentahydrate, sodium hypophosphite monohydrate and ammonium metavanadate is 281.44: (2.47-4.3): 1; the volume ratio of ethylene glycol and water is (5-2):(1-3); and the pH is adjusted to 1.5-3.5 after solution B is added into solution A drop by drop under stirring.

2. The method for preparing phosphorus-vanadium co-doped bismuth oxychloride with enhanced built-in electric field as described in claim 1, characterized in that, The mass ratio of potassium chloride and ammonium metavanadate is 41.63:

1.

3. The method for preparing phosphorus-vanadium co-doped bismuth oxychloride with enhanced built-in electric field as described in claim 1, characterized in that, The volume ratio of ethylene glycol and water is 4:

1.

4. The method for preparing phosphorus-vanadium co-doped bismuth oxychloride with enhanced built-in electric field as described in claim 1, characterized in that, The hydrothermal reaction time is 3-24h.

5. The method of producing a built-in electric field enhanced phosphorous-vanadium co-doped bismuth oxychloride according to claim 1, wherein The pH is adjusted to 2.

5.

6. A photocatalyst characterized by comprising: The preparation method is prepared by the preparation method of the phosphorus-vanadium co-doped bismuth oxychloride with enhanced built-in electric field as claimed in any one of claims 1 to 5.

7. The application of the photocatalyst as claimed in claim 6 in removing organic pollutants in water.

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