Preparation method and application of molybdenum selenide / oxygen defect bismuth oxybromide@gold three-phase Z-type heterojunction photocatalyst

Abstract

This invention relates to the field of nanoscale full-spectrum photocatalytic materials, and particularly to a method for preparing a molybdenum selenide / oxygen-deficient bismuth oxybromine@gold three-phase Z-type heterojunction photocatalyst. This method solves the problems of low photogenerated electron-hole separation efficiency, narrow full-spectrum response range, and poor stability in existing bismuth-based photocatalysts. The preparation method involves first preparing oxygen-deficient BiOBr nanospheres via a solvothermal method, then directly reacting tetrachloroauric acid with oleylamine in toluene to prepare small-particle-size monodisperse Au nanoparticles, which are then combined with oxygen-deficient BiOBr to prepare a BiOBr@Au nanosphere core-shell structure. Finally, a MoSe2 / oxygen-deficient BiOBr@Au three-phase composite material is prepared via a hydrothermal reaction. The catalyst of this invention exhibits absorption capacity under the full spectrum of light, and simultaneously achieves a synergistic enhancement of carrier separation efficiency and strong redox capability, demonstrating excellent photocatalytic activity and the ability to efficiently degrade pollutants and produce hydrogen.

Description

Technical Field

[0001] This invention relates to the field of nano-full-spectrum photocatalytic materials technology, and in particular to a method for preparing and applying a molybdenum selenide / oxygen-deficient bismuth oxybromine@gold triphase Z-type heterojunction photocatalyst. Background Technology

[0002] The environmental problems caused by organic wastewater have attracted much attention. Advanced oxidation processes (AOPs) are commonly used for the removal of organic wastewater due to their advantages such as low cost, easy control of operating conditions, and high wastewater treatment efficiency. Among the many AOP technologies, photocatalytic oxidation technology has gained widespread attention because it can achieve deep mineralization of highly toxic and recalcitrant organic pollutants. However, designing efficient, inexpensive, stable, and full-spectrum photocatalysts that are easy to industrially produce and applying them to the treatment of organic wastewater has become a pressing issue.

[0003] In recent years, due to the continuous consumption of fossil fuels and the increased environmental pollution caused by their combustion, the search for alternative and sustainable energy sources has been a major concern. From this perspective, hydrogen is the most attractive clean energy source because of its high energy density and pollution-free combustion products. In this context, semiconductor photocatalytic hydrogen production is a promising clean method, and the development of highly efficient photocatalysts has attracted much attention.

[0004] BiOBr, a typical narrow-bandgap layered compound semiconductor, has a PbFCl-type crystal structure with a space group of P4 / nmm, belonging to the typical tetragonal crystal system. Compared with the commonly used TiO2 photocatalyst, BiOBr has advantages such as a narrower bandgap and easier excitation by visible light. However, BiOBr still suffers from drawbacks such as low photogenerated electron-hole separation rate, narrow full-spectrum response range, difficulty in large-scale production, and poor stability. To overcome these bottlenecks, this invention introduces oxygen defects on the BiOBr surface to reduce the interfacial charge transfer barrier and constructs a heterojunction structure with other semiconductor materials. This improves the carrier transfer rate, compresses the bandgap of BiOBr, and significantly enhances its photocatalytic activity. Summary of the Invention

[0005] This invention proposes a method for preparing a molybdenum selenide / oxygen-deficient bismuth oxybromine@gold triphase Z-type heterojunction photocatalyst to address the problems of low photogenerated electron-hole separation efficiency, narrow full-spectrum response range, difficulty in large-scale production, and poor stability in existing bismuth-based photocatalysts. The purpose of this invention is to provide a method for preparing a molybdenum selenide / oxygen-deficient bismuth oxybromine@gold triphase Z-type heterojunction photocatalyst. A hydrothermal-oil amine reduction method is used to prepare the molybdenum selenide / oxygen-deficient bismuth oxybromine@gold composite material. In-situ reduction and high-temperature, high-pressure control of surface structure and morphology, as well as the introduction of surface defects, improve the photocatalytic performance of bismuth oxybromine, enhance the catalytic activity of the catalyst, and achieve effective separation of photogenerated carriers while maintaining their strong redox capabilities. This invention also provides an application of the molybdenum selenide / oxygen-deficient bismuth oxybromine@gold triphase Z-type heterojunction photocatalyst.

[0006] The first objective of this invention is to provide a method for preparing a molybdenum selenide / oxygen-deficient bismuth oxybromine@gold triphase Z-type heterojunction photocatalyst, comprising the following steps:

[0007] (1) Preparation of nanoflower BiOBr-OVs:

[0008] Bismuth nitrate pentahydrate and polyvinylpyrrolidone-K30 were dissolved in a mixed solution of ethylene glycol and deionized water by ultrasound and stirring. Potassium bromide was then added to the solution, and the solution was stirred at room temperature. The resulting transparent solution was transferred to a 50 mL high-pressure reactor for reaction. After the reaction was completed, the product was obtained by centrifugation, washed with water and ethanol, and vacuum dried at 60-80 °C for 5-7 h to obtain flower-shaped BiOBr-OVs samples with surface oxygen defect modification.

[0009] (2) Preparation of BiOBr-OVs@Au:

[0010] Oleylamine containing tetrachloroauric acid was mixed with toluene and added to a flask. The mixture was then heated in an oil bath to 60-80°C for 5-6 hours under nitrogen protection and magnetic stirring. After cooling the product to room temperature, ethanol was added, and Au nanoparticles were obtained by centrifugation. The nanoparticles were then dispersed in 20 mL of heptane by sonication and stirring to form a red dispersion. The red dispersion was mixed with 3-mercaptopropionic acid in a flask, and the resulting solution was stirred at room temperature. After centrifugation, the precipitate was washed with hexane and ethanol, and then dispersed in hexane by sonication and stirring to obtain an Au nanoparticle suspension. BiOBr-OVs were mixed with the Au nanoparticle suspension and hexane, and stirred by sonication at room temperature. The final product was vacuum dried at 50-70°C for 2-3 hours to obtain the BiOBr-OVs@Au sample.

[0011] (3) Preparation of MoSe2 / BiOBr-OVs@Au three-phase photocatalyst:

[0012] BiOBr-OVs@Au was dispersed in a solution containing Na2MoO4·2H2O by ultrasonication and stirring. 30mL A suspended solid solution was formed in deionized water. A solution of N2H4·2H2O containing dissolved Se powder was gradually added dropwise to the suspended solid solution under magnetic stirring. The mixture was then transferred to a 50 mL high-pressure reactor, washed with water and ethanol, and freeze-dried to obtain the three-phase photocatalyst MoSe2 / BiOBr@Au.

[0013] Preferably, in step (1), the mass ratio of bismuth nitrate pentahydrate, polyvinylpyrrolidone-K30 and potassium bromide is 0.73:0.7:0.18.

[0014] Preferably, the volume ratio of deionized water to ethylene glycol in step (1) is 1:1 to 1:6.

[0015] Preferably, the Au mass fraction of BiOBr-OVs@Au in step (2) is 3%-9%.

[0016] Preferably, in step (2), the volume ratio of oleylamine to toluene is 1:9; and the volume ratio of n-hexane to ethanol is 2:1.

[0017] Preferably, the MoSe2 mass fraction of the MoSe2 / BiOBr@Au in step (3) is 4%-12%.

[0018] Preferably, the reaction temperature in the high-pressure reactor in step (1) is 120-200℃ and the reaction time is 10-24h; the reaction temperature in the high-pressure reactor in step (3) is 150-200℃ and the reaction time is 12-48h.

[0019] A second objective of this invention is to provide an application of a molybdenum selenide / oxygen-deficient bismuth oxybromine@gold triphase Z-type heterojunction photocatalyst, wherein the triphase photocatalyst MoSe2 / BiOBr@Au can be used to degrade pollutants and for photocatalytic hydrogen evolution.

[0020] MoSe2 is a typical two-dimensional layered crystal with a narrow band gap and a strong reduction potential, and its light absorption extends into the near-infrared range. This invention focuses on preparing a MoSe2 / BiOBr-OVs@Au Z-type heterojunction photocatalyst based on Au as an electron mediator. The research and design revolve around enhancing the efficiency of full-spectrum photocatalytic removal of organic pollutants from wastewater and hydrogen production through defect / heterojunction coupling. The addition of MoSe2 and Au lowers the required excitation energy and creates an internal electric field, which, from a mechanical perspective, increases the driving force for electron transfer. This achieves effective separation of photogenerated carriers in the catalyst, suppresses electron-hole recombination, and maintains their strong redox capabilities. Furthermore, it exhibits excellent light absorption performance under full-spectrum light irradiation in hydrogen evolution applications.

[0021] This invention uses oxygen-deficient BiOBr nanospheres as the core and Au nanoparticles as the shell, loading MoSe2 nanosheets onto the surface of BiOBr@Au via a hydrothermal reaction. First, oxygen-deficient BiOBr nanospheres are prepared via a solvothermal method. Then, tetrachloroauric acid is directly reacted with oleylamine in toluene to prepare monodisperse Au nanoparticles with a small particle size distribution. These are then combined with oxygen-deficient BiOBr to prepare BiOBr@Au nanospheres. Finally, a MoSe2 / oxygen-deficient BiOBr@Au three-phase composite material is prepared via a hydrothermal reaction. The catalyst in this invention exhibits absorption capacity across the entire spectrum (UV, visible, and infrared light), simultaneously achieving a synergistic enhancement of carrier separation efficiency and strong redox capability, and demonstrating excellent photocatalytic activity, enabling efficient degradation of pollutants and hydrogen production.

[0022] The present invention has at least the following beneficial effects:

[0023] Compared with existing photocatalytic wastewater degradation and hydrogen production materials, this invention has the following advantages:

[0024] This invention uses BiOBr-OVs materials, where oxygen vacancies have a significant advantage in photocatalytic redox reactions. These materials have the ability to capture electrons, reduce band gaps, and promote adsorption on substrate molecule surfaces, thereby enabling the catalyst synthesized in this patent to have higher catalytic activity.

[0025] The MoSe2 / BiOBr-OVs@Au three-phase composite photocatalytic material prepared in this invention belongs to the Z-type heterojunction category. By using Au as an electron mediator to construct an internal electric field, it can accelerate the carrier migration rate and suppress the recombination of electrons and holes in MoSe2 and BiOBr-OVs more effectively than traditional type II heterojunctions and two-phase Z-type heterojunctions, thereby effectively improving the efficiency of photocatalytic degradation and photocatalytic hydrogen production.

[0026] The MoSe2 / BiOBr-OVs@Au three-phase composite photocatalyst material prepared in this invention can expand the light absorption wavelength range due to the addition of MoSe2 and the surface plasmon resonance of Au. Thus, the catalyst exhibits good light absorption performance in the entire light region under ultraviolet, visible and infrared light irradiation.

[0027] The MoSe2 / BiOBr-OVs@Au three-phase composite photocatalyst material prepared in this invention has a core-shell structure. The core-shell structure has a high specific surface area and a large contact area, providing more reaction sites. Furthermore, this unique structure can improve the efficiency of charge separation and interfacial charge transfer, as well as enhance the light collection efficiency, thereby improving the catalyst activity.

[0028] This invention prepares MoSe2 / BiOBr-OVs@Au three-phase composite photocatalyst material using a hydrothermal-oil amine reduction method. The surface structure and morphology are controlled by in-situ reduction and high temperature and high pressure, and surface oxygen defects are introduced. The overall experimental method is clear, the selected instruments and equipment are easy to operate, the process conditions are controllable, and it exhibits good degradation and hydrogen production performance. It has good development prospects in addressing environmental pollution and energy shortage issues. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present invention and, together with the specification, serve to explain the technical solutions of the present invention.

[0030] Figure 1 The XRD patterns of different catalysts prepared in the embodiments of the present invention are shown below.

[0031] Figure 2 These are SEM images of the monomer, two-phase, and three-phase catalysts in the embodiments of the present invention, as well as their overall and microscopic images; (wherein: Figure 2 a is a microscopic SEM image of the nanoflower BiOBr-OVs from Example 1; Figure 2 b is a microscopic SEM image of the MoSe2 monomer; Figure 2 c is a microscopic SEM image of BiOBr-OVs@Au from Example 4; Figure 2 d is a microscopic SEM image of the MoSe2 / BiOBr-OVs@Au three-phase photocatalyst from Example 8;

[0032] Figure 3 This is a TEM image of the heterojunction interface of the three-phase catalyst material synthesized in Example 8 of the present invention;

[0033] Figure 4 This is a graph showing the degradation rates of different catalysts in the embodiments of the present invention;

[0034] Figure 5This is a graph showing the hydrogen production rates of different catalysts in the embodiments of the present invention. Detailed Implementation

[0035] To better explain the present invention, the following description, in conjunction with the accompanying drawings and embodiments, further elaborates on the content of the present invention.

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; the materials and reagents used in the following examples are commercially available unless otherwise specified.

[0037] Example 1

[0038] 0.73 g of bismuth nitrate pentahydrate and 0.7 g of polyvinylpyrrolidone-K30 were dissolved in a 6:1 mixture of ethylene glycol and deionized water using ultrasound and stirring. Then, 0.18 g of potassium bromide was added to the solution, and the mixture was stirred at room temperature for 0.5 h. The resulting transparent solution was transferred to a 50 mL high-pressure reactor and kept at 160 °C for 12 h. The solution was then washed with water and ethanol and vacuum dried at 60 °C for 6 h to obtain a flower-shaped BiOBr-OVs sample with surface oxygen defect modification.

[0039] Test Example 1

[0040] 25 mg of the BiOBr-OVs sample prepared in Example 1 was weighed and dispersed into 50 mL of a 10 mg / L 17α-ethinyl estradiol solution. The reaction was carried out in the dark for 30 min, and then a 300 W xenon lamp was used as the light source for photocatalytic degradation. 3 mL of the reaction solution was sampled every 15 min, and the suspended solid particles were filtered through a microporous membrane. The concentration of 17α-ethinyl estradiol was determined by high performance liquid chromatography (HPLC), and the degradation rate was calculated to be 37%.

[0041] Example 2

[0042] 5 mL of oleylamine containing 0.25 mmol tetrachloroauric acid was mixed with 45 mL of toluene and added to a 100 mL flask. The mixture was then heated to 80 °C in an oil bath under nitrogen protection and magnetic stirring for 5 h. After the product was cooled to room temperature, ethanol was added to it, and Au nanoparticles were obtained by centrifugation. The mixture was dispersed in 20 mL of heptane by sonication and stirring to form a red dispersion. This dispersion was then mixed with 8 mL of 3-mercaptopropionic acid in a 50 mL flask. The resulting mixture was stirred for 12 h at room temperature. After centrifugation, the precipitate was washed with hexane and ethanol in a volume ratio of 2:1. The precipitate was then dispersed in 50 mL of hexane by sonication and stirring to obtain a 1 g / L Au nanoparticle suspension. 0.3 g of BiOBr-OVs prepared in Example 1 was mixed with 9 mL of the Au nanoparticle suspension and 41 mL of hexane. The mixture was sonicated for 0.5 h and stirred at room temperature for 2 h. The final product was vacuum dried at 50 °C for 2 h to obtain a BiOBr-OVs@Au sample with an Au mass fraction of 3%.

[0043] Test Example 2

[0044] 25 mg of the BiOBr-OVs@Au sample prepared in Example 2 was weighed and dispersed into 50 mL of a 10 mg / L 17α-ethinyl estradiol solution. The reaction was carried out in the dark for 30 min, and then a 300 W xenon lamp was used as the light source for photocatalytic degradation. 3 mL of the reaction solution was sampled every 15 min, and the suspended solid particles were filtered through a microporous membrane. The concentration of 17α-ethinyl estradiol was determined by high performance liquid chromatography (HPLC), and the degradation rate was calculated to be 49%.

[0045] Example 3

[0046] The difference between this example and Example 2 is that it is mixed with 15 mL of Au nanoparticle suspension and 35 mL of n-hexane. All other preparation conditions are the same as in Example 2, and a BiO Br-OVs@Au sample with an Au mass fraction of 5% is obtained.

[0047] Test Example 3

[0048] 25 mg of the BiOBr-OVs@Au sample prepared in Example 3 was weighed and dispersed into 50 mL of a 10 mg / L 17α-ethinyl estradiol solution. The reaction was carried out in the dark for 30 min, and then a 300 W xenon lamp was used as the light source for photocatalytic degradation. 3 mL of the reaction solution was sampled every 15 min, and the suspended solid particles were filtered through a microporous membrane. The concentration of 17α-ethinyl estradiol was determined by high performance liquid chromatography (HPLC), and the degradation rate was calculated to be 61%.

[0049] Example 4

[0050] The difference between this embodiment and Example 2 is that it is mixed with 21 mL of Au nanoparticle suspension and 29 mL of n-hexane. All other preparation conditions are the same as in Example 2, and a BiO Br-OVs@Au sample with an Au mass fraction of 7% is obtained.

[0051] Test Example 4

[0052] 25 mg of the BiOBr-OVs@Au sample prepared in Example 4 was weighed and dispersed into 50 mL of a 10 mg / L 17α-ethinyl estradiol solution. The reaction was carried out in the dark for 30 min, and then a 300 W xenon lamp was used as the light source for photocatalytic degradation. 3 mL of the reaction solution was sampled every 15 min, and the suspended solid particles were filtered through a microporous membrane. The concentration of 17α-ethinyl estradiol was determined by high performance liquid chromatography (HPLC), and the degradation rate was calculated to be 72%.

[0053] Example 5

[0054] The difference between this embodiment and Example 2 is that it is mixed with 27 mL of Au nanoparticle suspension and 23 mL of n-hexane. All other preparation conditions are the same as in Example 2, and a BiO Br-OVs@Au sample with an Au mass fraction of 9% is obtained.

[0055] Test Example 5

[0056] 25 mg of the BiOBr-OVs@Au sample prepared in Example 5 was weighed and dispersed into 50 mL of a 10 mg / L 17α-ethinyl estradiol solution. The reaction was carried out in the dark for 30 min, and then a 300 W xenon lamp was used as the light source for photocatalytic degradation. 3 mL of the reaction solution was sampled every 15 min, and the suspended solid particles were filtered through a microporous membrane. The concentration of 17α-ethinyl estradiol was determined by high performance liquid chromatography (HPLC), and the degradation rate was calculated to be 58%.

[0057] Example 6

[0058] 0.3 g of BiOBr-OVs@Au prepared in Example 4 was dispersed in 30 mL of deionized water containing 0.012 g of Na2MoO4·2H2O by ultrasonication and stirring to form a suspension. 10 mL of N2H4·2H2O solution containing 0.007 g of Se powder was gradually added dropwise to the suspension under magnetic stirring, and stirring continued for 30 min. The mixture was then transferred to a 50 mL high-pressure reactor and maintained at 180 °C for 24 h. After washing with water and ethanol, the mixture was freeze-dried to obtain MoSe2 / BiOBr-OVs@Au with a MoSe2 mass fraction of 4%.

[0059] Test Example 6

[0060] 25 mg of the MoSe2 / BiOBr-OVs@Au sample prepared in Example 6 was weighed and dispersed into 50 mL of a 10 mg / L 17α-ethinyl estradiol solution. The reaction was carried out in the dark for 30 min, and then a 300 W xenon lamp was used as the light source for photocatalytic degradation. 3 mL of the reaction solution was sampled every 15 min, and the suspended solid particles were filtered through a microporous membrane. The concentration of 17α-ethinyl estradiol was determined by high performance liquid chromatography (HPLC), and the degradation rate was calculated to be 83%.

[0061] 25 mg of the photocatalyst prepared in Example 6 was suspended in 100 mL of an aqueous solution containing 10 vol% triethanolamine as a sacrificial agent. The suspension was sealed in a quartz reactor. The system was then degassed for 30 min to remove air. A 300 W xenon lamp was used as the light source, and periodic analysis of the H2 products by gas chromatography yielded a hydrogen production rate of 7.84 mmol / g. -1 L -1 .

[0062] Example 7

[0063] The difference between this embodiment and Example 6 is that 0.019 g of Na2MoO4·2H2O and 0.011 g of Se powder were added. All other preparation conditions were the same as in Example 6, and MoSe2 / BiOBr-OVs@Au with a MoSe2 mass fraction of 6% was obtained.

[0064] Test Example 7

[0065] 25 mg of the MoSe2 / BiOBr-OVs@Au sample prepared in Example 7 was weighed and dispersed into 50 mL of a 10 mg / L 17α-ethinyl estradiol solution. The reaction was carried out in the dark for 30 min, and then a 300 W xenon lamp was used as the light source for photocatalytic degradation. 3 mL of the reaction solution was sampled every 15 min, and the suspended solid particles were filtered through a microporous membrane. The concentration of 17α-ethinyl estradiol was determined by high performance liquid chromatography (HPLC), and the degradation rate was calculated to be 87%.

[0066] 25 mg of the photocatalyst prepared in Example 7 was suspended in 100 mL of an aqueous solution containing 10 vol% triethanolamine as a sacrificial agent. The suspension was sealed in a quartz reactor. The system was then degassed for 30 min to remove air. A 300 W xenon lamp was used as the light source, and periodic analysis of the H2 products by gas chromatography yielded a hydrogen production rate of 8.96 mmol / g. -1 L -1 .

[0067] Example 8

[0068] The difference between this embodiment and Example 6 is that 0.03g of Na2MoO4·2H2O and 0.019g of Se powder were added. All other preparation conditions were the same as in Example 6, and MoSe2 / BiOBr-OVs@Au with a MoSe2 mass fraction of 10% was obtained.

[0069] Test Example 8

[0070] 25 mg of the MoSe2 / BiOBr-OVs@Au sample prepared in Example 8 was weighed and dispersed into 50 mL of a 10 mg / L 17α-ethinyl estradiol solution. The reaction was carried out in the dark for 30 min, and then a 300 W xenon lamp was used as the light source for photocatalytic degradation. 3 mL of the reaction solution was sampled every 15 min, and the suspended solid particles were filtered through a microporous membrane. The concentration of 17α-ethinyl estradiol was determined by high performance liquid chromatography (HPLC), and the degradation rate was calculated to be 96%.

[0071] 25 mg of the photocatalyst prepared in Example 8 was suspended in 100 mL of an aqueous solution containing 10 vol% triethanolamine as a sacrificial agent. The suspension was sealed in a quartz reactor. The system was then degassed for 30 min to remove air. A 300 W xenon lamp was used as the light source, and gas chromatography was used to periodically analyze the H2 products, yielding a hydrogen production rate of 12.08 mmol / g. -1 L -1 .

[0072] Example 9

[0073] The difference between this embodiment and Example 6 is that 0.037g of Na2MoO4·2H2O and 0.022g of Se powder were added. All other preparation conditions were the same as in Example 6, and MoSe2 / BiOBr-OVs@Au with a MoSe2 mass fraction of 12% was obtained.

[0074] Test Example 9

[0075] 25 mg of the MoSe2 / BiOBr-OVs@Au sample prepared in Example 9 was weighed and dispersed into 50 mL of a 10 mg / L 17α-ethinyl estradiol solution. The reaction was carried out in the dark for 30 min, and then a 300 W xenon lamp was used as the light source for photocatalytic degradation. 3 mL of the reaction solution was sampled every 15 min, and the suspended solid particles were filtered through a microporous membrane. The concentration of 17α-ethinyl estradiol was determined by high performance liquid chromatography (HPLC), and the degradation rate was calculated to be 92%.

[0076] 25 mg of the photocatalyst prepared in Example 9 was suspended in 100 mL of an aqueous solution containing 10 vol% triethanolamine as a sacrificial agent. The suspension was then sealed in a 250 mL quartz reactor. The system was then degassed for 30 min to remove air. A 300 W xenon lamp was used as the light source, and gas chromatography was used to periodically analyze the H2 products, yielding a hydrogen production rate of 10.56 mmol / g. -1 L -1 .

[0077] Example 10

[0078] 0.3 g of BiOBr-OVs prepared in Example 1 was dispersed by ultrasonication and stirring in 30 mL of deionized water containing 0.03 g of Na2MoO4·2H2O to form a suspension. 10 mL of N2H4·2H2O solution containing 0.019 g of Se powder was gradually added dropwise to the suspension under magnetic stirring, and stirring continued for 30 min. The mixture was then transferred to a 50 mL high-pressure reactor and maintained at 180 °C for 24 h. After washing with water and ethanol, the mixture was freeze-dried to obtain MoSe2 / BiOBr-OVs with a MoSe2 mass fraction of 10%.

[0079] Test Case 10

[0080] 25 mg of the MoSe2 / BiOBr-OVs sample prepared in Example 10 was weighed and dispersed in 50 mL of a 10 mg / L 17α-ethinyl estradiol solution. The reaction was carried out in the dark for 30 min, and then a 300 W xenon lamp was used as the light source for photocatalytic degradation. 3 mL of the reaction solution was sampled every 15 min, and the suspended solid particles were filtered through a microporous membrane. The concentration of 17α-ethinyl estradiol was determined by high performance liquid chromatography (HPLC), and the degradation rate was calculated to be 57%.

[0081] 25 mg of the photocatalyst prepared in Example 10 was suspended in 100 mL of an aqueous solution containing 10 vol% triethanolamine as a sacrificial agent. The suspension was sealed in a quartz reactor. The system was then degassed for 30 min to remove air. A 300 W xenon lamp was used as the light source, and periodic analysis of the H2 products by gas chromatography yielded a hydrogen production rate of 5.09 mmol / g. -1 L -1 .

[0082] The XRD patterns of the catalysts prepared in the above embodiments are as follows: Figure 1 As shown, Figure 1The XRD spectra of MoSe2 monomer, the MoSe2 / BiOBr-OVs@Au three-phase photocatalyst prepared in Example 8, the BiOBr-OVs@Au prepared in Example 4, and the nanoflower BiOBr-OVs prepared in Example 1 are shown in sequence. After Au, MoSe2 and BiOBr-OVs are combined, characteristic peaks of Au and MoSe2 appear in the composite catalyst, indicating that Au and MoSe2 are loaded onto BiOBr-OVs.

[0083] Scanning electron microscope, such as Figure 2 , Figure 3 As shown, Figure 2 a is a microscopic SEM image of the BiOBr-OV nanoflowers prepared in Example 1; Figure 2 b is a microscopic SEM image of the MoSe2 monomer; Figure 2 c is a microscopic SEM image of BiOBr-OVs@Au prepared in Example 4; Figure 2 d is a microscopic SEM image of the MoSe2 / BiOBr-OVs@Au three-phase photocatalyst prepared in Example 8; Figure 3 This is a TEM image of the heterojunction interface of the MoSe2 / BiOBr-OVs@Au three-phase catalyst material prepared in Example 8.

[0084] from Figure 2 , Figure 3 As can be clearly seen in the SEM images, the nanoflowers BiOBr-OVs prepared in Example 1 have excellent morphology. Figure 2 a), and the triphase photocatalytic material synthesized in Example 8 finally possesses a good core-shell structure ( Figure 2 d) The Au particle loading effect is significantly and clearly visible, with uniform dispersion, providing abundant reactive sites. Figure 2 c), and the Z-type heterojunction interface formed by BiOBr-OVs@Au and MoSe2 can be clearly observed. Figure 3 ).

[0085] The degradation rate of the catalyst prepared by this patent is, for example, Figure 4 As shown. Figure 4 The degradation rate diagrams are shown for the following three-phase photocatalysts in sequence: BiOBr monomer, BiOBr-OVs nanoflowers prepared in Example 1, MoSe2 / BiOBr-OVs prepared in Example 10, BiOBr-OVs@Au prepared in Example 4, and MoSe2 / BiOBr-OVs@Au prepared in Example 8.

[0086] Depend on Figure 4It can be seen that the degradation rate of BiOBr monomer is 16% in 90 min; the degradation rate of nanoflower BiOBr-OVs prepared in Example 1 is 37% in 90 min; the degradation rate of MoSe2 / BiOBr-OVs prepared in Example 10 is 57% in 90 min; the degradation rate of BiOBr-OVs@Au prepared in Example 4 is 72% in 90 min; finally, by controlling the mass ratio of Au to 7% and the mass ratio of MoSe2 to 10%, the MoSe2 / BiOBr-OVs@Au catalyst prepared in Example 8 has the highest degradation efficiency, reaching 96% in 90 min.

[0087] The degradation rate of the catalyst prepared by this patent is, for example, Figure 5 As shown. Figure 5 The hydrogen production rates of the three-phase photocatalysts, namely MoSe2 monomer, MoSe2 / BiOBr-OVs prepared in Example 10, and MoSe2 / BiOBr-OVs@Au prepared in Example 8, are shown in the following diagrams.

[0088] Depend on Figure 5 As can be seen, by controlling the Au mass ratio to 7% and the MoSe2 mass ratio to 10%, the hydrogen production rate of the MoSe2 / BiOBr-OVs@Au prepared in Example 8 was 12.08 mmol / g. -1 L -1 Compared to the MoSe2 monomer hydrogen production rate of 2.62 mmol / g, -1 L -1 The hydrogen production rate of MoSe2 / BiOBr-OVs prepared in Example 10 was 5.09 mmol / g. -1 L -1 The hydrogen production rate of the catalyst MoSe2 / BiOBr-OVs@Au is 2.37 times that of the catalyst MoSe2 / BiO Br and 4.65 times that of the single MoSe2 catalyst.

[0089] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing a molybdenum selenide / oxygen-deficient bismuth oxybromine@gold three-phase Z-type heterojunction photocatalyst, characterized in that, Includes the following steps: (1) Preparation of nanoflower BiOBr-OVs: Bismuth nitrate pentahydrate and polyvinylpyrrolidone-K30 were dissolved in a mixed solution of ethylene glycol and deionized water by ultrasound and stirring. Potassium bromide was then added to the solution, and the solution was stirred at room temperature. The resulting transparent solution was transferred to a 50 mL high-pressure reactor for reaction. After the reaction was completed, the product was obtained by centrifugation, washed with water and ethanol, and vacuum dried at 60-80 °C for 5-7 h to obtain flower-shaped BiOBr-OVs samples with surface oxygen defect modification. (2) Preparation of BiOBr-OVs@Au: Oleylamine containing tetrachloroauric acid was mixed with toluene and added to a flask. The mixture was then heated in an oil bath to 60-80°C for 5-6 hours under nitrogen protection and magnetic stirring. After cooling the product to room temperature, ethanol was added, and Au nanoparticles were obtained by centrifugation. The nanoparticles were then dispersed in 20 mL of heptane by sonication and stirring to form a red dispersion. The red dispersion was mixed with 3-mercaptopropionic acid in a flask, and the resulting solution was stirred at room temperature. After centrifugation, the precipitate was washed with hexane and ethanol, and then dispersed in hexane by sonication and stirring to obtain an Au nanoparticle suspension. BiOBr-OVs were mixed with the Au nanoparticle suspension and hexane, and stirred by sonication at room temperature. The final product was vacuum dried at 50-70°C for 2-3 hours to obtain the BiOBr-OVs@Au sample. (3) Preparation of MoSe2 / BiOBr-OVs@Au three-phase photocatalyst: BiOBr-OVs@Au was dispersed in 30 mL of deionized water containing Na2MoO4·2H2O by ultrasonication and stirring to form a suspended solid solution. A solution of N2H4·2H2O containing dissolved Se powder was gradually added dropwise to the above suspended solid solution under magnetic stirring and stirring was continued. Then, the solution was transferred to a 50 mL high-pressure reactor, washed with water and ethanol, and freeze-dried to obtain the three-phase photocatalyst MoSe2 / BiOBr@Au.

2. The preparation method of the molybdenum selenide / oxygen-deficient bismuth oxybromine@gold three-phase Z-type heterojunction photocatalyst according to claim 1, characterized in that, In step (1), the mass ratio of bismuth nitrate pentahydrate, polyvinylpyrrolidone-K30, and potassium bromide is 0.73:0.7:0.

18.

3. The method for preparing a molybdenum selenide / oxygen-deficient bismuth oxybromine@gold three-phase Z-type heterojunction photocatalyst according to claim 1, characterized in that, The volume ratio of deionized water to ethylene glycol in step (1) is 1:1 to 1:

6.

4. The method for preparing a molybdenum selenide / oxygen-deficient bismuth oxybromine@gold three-phase Z-type heterojunction photocatalyst according to claim 1, characterized in that, The Au mass fraction of BiOBr-OVs@Au in step (2) is 3%-9%.

5. The preparation method of the molybdenum selenide / oxygen-deficient bismuth oxybromine@gold three-phase Z-type heterojunction photocatalyst according to claim 1, characterized in that, Step (2) The volume ratio of oleylamine to toluene is 1:9; the volume ratio of n-hexane to ethanol is 2:

1.

6. The method for preparing a molybdenum selenide / oxygen-deficient bismuth oxybromine@gold three-phase Z-type heterojunction photocatalyst according to claim 1, characterized in that, The MoSe2 mass fraction of the MoSe2 / BiOBr@Au in step (3) is 4%-12%.

7. The method for preparing a molybdenum selenide / oxygen-deficient bismuth oxybromine@gold three-phase Z-type heterojunction photocatalyst according to claim 1, characterized in that, The reaction temperature in the autoclave in step (1) is 120-200℃ and the reaction time is 10-24h; the reaction temperature in the autoclave in step (3) is 150-200℃ and the reaction time is 12-48h.

8. The three-phase photocatalyst MoSe2 / BiOBr@Au was prepared by the method according to claim 1.

9. An application of the three-phase photocatalyst according to claim 8, characterized in that, The triphase photocatalyst can be used to degrade pollutants.

10. An application of the three-phase photocatalyst according to claim 8, characterized in that, The three-phase photocatalyst can be used for photocatalytic hydrogen evolution.

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