Yb < 3 + > / Er < 3 + > co-doped full-spectrum response Ti-MOF / BiOBr S-type heterojunction as well as preparation method and application thereof

Abstract

The invention relates to the technical field of photocatalysis, in particular to a Yb < 3 + > / Er < 3 + > co-doped full-spectrum response Ti-MOF / BiOBr S type heterojunction as well as a preparation method and application thereof. The invention provides an S-type heterojunction composite catalyst, which is mainly prepared from squaric acid, a titanium source, Yb < 3 + > and Er < 3 + > doped BiOBr nanosheets, and the mass ratio of the BiOBr nanosheets in the catalyst is 60%-95%. The high specific surface area of the IEF-11 is beneficial to pollutant enrichment, and the addition of the nanosheet can expand the photoresponse range and can be used as an electron trapping agent, so that the sunlight utilization rate and the photocatalytic performance are improved; the constructed S-type heterojunction can promote separation of photon-generated carriers, and meanwhile, the strong oxidation-reduction capacity of a composite system is reserved. The catalyst has the capabilities of full-spectrum response, efficient degradation of organic pollutants and inactivation of microorganisms, and has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The application relates to the field of photocatalysis, in particular to a Yb 3+ / Er 3+ co-doped full-spectrum response Ti-MOF / BiOBr S-type heterojunction and a preparation method and application thereof. BACKGROUND

[0002] With the continuous advancement of urbanization and industrialization of human society, the discharge of various types of wastewater continues to increase. The combined pollution of antibiotic-resistant pathogenic microorganisms and persistent organic pollutants such as tetracyclines and synthetic dyes in water bodies has become a serious challenge in the field of water safety. Under this background, heterogeneous photocatalysis technology based on semiconductor photocatalysts is considered as a promising strategy because it can utilize sunlight to achieve the dual functions of deep mineralization of pollutants and inactivation of microorganisms.

[0003] Ti-MOF (IEF-11) has significant potential in the field of photocatalysis due to its three-dimensional pore structure and synergistic light response characteristics of titanium-oxygen cluster-square acid ligand. However, single IEF-11 has defects such as high recombination rate of photo-generated carriers, lack of near-infrared light response, and insufficient surface active sites, which greatly limits its actual efficiency. To solve this technical problem, Chinese Patent Application CN120054648A discloses an IEF-11 / WO 3-x S-type heterojunction catalyst. This catalyst can effectively promote the separation of photo-generated carriers and retain the strong redox ability of the material itself, ultimately achieving full-spectrum response while having certain organic pollutant degradation and microbial inactivation ability. However, this catalyst still has obvious limitations. On the one hand, its microbial inactivation efficiency still has a lot of room for improvement, specifically: the residual rate of bacteria after 30 mg IEF-11 / WO 3-x S-type heterojunction catalyst is still as high as 85% and 68% respectively after being irradiated by near-infrared light source and full-spectrum light source for 15 min, and the inactivation efficiency is obviously insufficient. On the other hand, although this catalyst exhibits excellent degradation ability for easily degradable antibiotics such as tetracyclines, its degradation ability for quinolone antibiotics such as ciprofloxacin is poor. This type of quinolone antibiotic has a relatively higher chemical bond energy and is not easy to be activated by the catalyst due to the presence of a stable quinoline ring conjugated system and a strong electron-withdrawing group in its molecular structure. The residue of this type of difficult-to-degrade antibiotic will directly give rise to antibiotic-resistant bacteria, harm aquatic biological communities, and lead to the difficulty of the catalyst to meet the needs of actual water treatment scenarios.

[0004] Therefore, developing a catalyst that has full-spectrum response, high-efficiency degradation of quinolone antibiotics such as ciprofloxacin, and inactivation of microorganisms has become a key requirement for solving the current problem of combined pollution in water bodies. SUMMARY

[0005] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of existing photocatalysts that cannot simultaneously possess full-spectrum response and efficient degradation of quinolone-based recalcitrant antibiotics and inactivation of microorganisms, and to provide an S-type heterojunction composite catalyst.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned S-type heterojunction composite catalyst.

[0007] Another objective of this invention is to provide an application of the above-mentioned S-type heterojunction composite catalyst in photocatalytic killing of microorganisms or photocatalytic degradation of organic pollutants.

[0008] Another objective of this invention is to provide a method for photocatalytic killing of microorganisms.

[0009] Another object of the present invention is to provide a method for photocatalytic degradation of organic pollutants.

[0010] Another object of the present invention is to provide a photocatalyst composition.

[0011] The above-mentioned objective of this invention is achieved through the following technical solution: This invention protects an S-type heterojunction composite catalyst, which mainly consists of squaric acid, a titanium source, and Yb. 3+ and Er 3+ It was prepared using doped BiOBr nanosheets; Among them, Yb in the S-type heterojunction composite catalyst 3+ and Er 3+ The mass percentage of doped BiOBr nanosheets is 60% to 95%.

[0012] This invention provides an S-type heterojunction composite catalyst, which mainly consists of squaric acid, titanium source, and Yb. 3+ and Er 3+ The catalyst was prepared using doped BiOBr nanosheets, with the BiOBr nanosheets comprising 60%–95% of the total mass. In this S-shaped heterojunction system, IEF-11, due to its high specific surface area, can effectively enrich organic pollutants and microorganisms in water, providing ample reaction targets for subsequent photocatalytic reactions; Yb 3+ Er 3+Rare earth ion doping of BiOBr nanosheets not only extends the photoresponse range of the catalyst but also acts as an electron trap to suppress photogenerated carrier recombination. Simultaneously, it synergizes with the semiconductor properties of the BiOBr nanosheets themselves—providing a stable active substrate for the photocatalytic reaction and significantly improving solar energy utilization and system photocatalytic activity. The S-shaped heterojunction constructed by these two elements promotes photogenerated carrier separation while retaining the strong redox capabilities of the composite system, thereby generating a large number of reactive oxygen species such as hydroxyl radicals and superoxide radicals. This disrupts the cell membrane structure of microorganisms, achieving highly efficient sterilization. This catalyst possesses a full-spectrum response and the ability to efficiently degrade recalcitrant organic pollutants and inactivate microorganisms, showing broad application prospects in environmental remediation and photocatalytic disinfection.

[0013] Preferably, in the S-type heterojunction composite catalyst, Yb 3+ and Er 3+ The mass percentage of doped BiOBr nanosheets is 65% to 90%.

[0014] More preferably, the S-type heterojunction composite catalyst contains Yb 3+ and Er 3+ The mass percentage of doped BiOBr nanosheets is 80%~90%.

[0015] Furthermore, the Yb 3+ and Er 3+ The preparation method of doped BiOBr nanosheets includes the following steps: S1. Bismuth salt, ytterbium salt, and erbium salt are mixed in an organic solvent, then bromide salt is added, and a solvothermal reaction is carried out. After post-treatment, the precursor is obtained. S2. Calcine the precursor obtained in step S1 at 300~500 °C to obtain the Yb. 3+ and Er 3+ Doped BiOBr nanosheets.

[0016] Furthermore, the bismuth salt includes bismuth nitrate, bismuth fluoride, bismuth trifluoroacetate, or a hydrate of any of the above bismuth salts.

[0017] Furthermore, the ytterbium salt includes ytterbium nitrate, ytterbium fluoride, ytterbium trifluoroacetate, or a hydrate of any of the above ytterbium salts.

[0018] Furthermore, the erbium salt includes erbium nitrate, erbium fluoride, erbium trifluoroacetate, or a hydrate of any of the above erbium salts.

[0019] Furthermore, the molar ratio of the bismuth salt, ytterbium salt, and erbium salt is 1:(0.1~0.2):(0.1~0.15).

[0020] Furthermore, the organic solvent is an alcohol reagent.

[0021] Furthermore, the alcohol reagent includes one or more of mannitol, ethylene glycol, and D-sorbitol.

[0022] Preferably, the organic solvent is mannitol.

[0023] Preferably, the mass-to-volume ratio of the bismuth salt to the organic solvent is 1 g: (150~300) mL.

[0024] Preferably, the mixing time is 0.5 to 1 hour.

[0025] Furthermore, the bromide salt includes one or more of potassium bromide, ammonium bromide, and sodium bromide.

[0026] Furthermore, the bromide salt is potassium bromide.

[0027] Furthermore, the molar ratio of the bismuth salt to the bromide salt is 1:(0.05~0.2).

[0028] Preferably, after adding the bromide salt, a mixing step may also be included.

[0029] More preferably, the mixing time is 10 to 30 minutes.

[0030] Furthermore, the temperature of the solvothermal process is 120~200 °C.

[0031] Furthermore, the solvothermal time is 12-24 h.

[0032] Furthermore, the post-processing includes washing and drying.

[0033] Preferably, the solvents used for washing are ethanol and water, in sequence.

[0034] Furthermore, the calcination time is 1-2 hours.

[0035] This invention protects a method for preparing the above-mentioned S-type heterojunction composite catalyst, comprising the following steps: Si. Yb 3+ and Er 3+ The doped BiOBr nanosheets, acidic reagent, and dispersion containing squaric acid were thoroughly mixed to obtain a mixed solution. Sii. Add the titanium source to the mixed solution obtained in step Si, carry out a solvothermal reaction, and then perform post-treatment to obtain the S-type heterojunction composite catalyst.

[0036] Furthermore, the acidic reagent includes one or more of glacial acetic acid, hydrochloric acid, and phosphoric acid. The acidic reagent provides an acidic environment for the preparation system of IEF-11, thereby promoting the directional formation and stable shaping of the IEF-11 crystal structure.

[0037] Furthermore, the acidic reagent is glacial acetic acid.

[0038] Furthermore, the Yb 3+ and Er 3+ The mass-to-volume ratio of doped BiOBr nanosheets to acidic reagents is 1 g: (1~10) mL.

[0039] Furthermore, the method for preparing the dispersion containing squaric acid includes the following steps: Squaric acid is fully dispersed in a reducing reagent to obtain a dispersion containing squaric acid.

[0040] Furthermore, the reducing agent is an alcohol-based reducing agent.

[0041] Furthermore, the alcohol reducing agent includes one or more of isopropanol, ethanol, and ethylene glycol. These agents, due to the presence of a hydroxyl group and an attached α-hydrogen in their molecules, possess mild and controllable reducing properties, making them suitable for the redox requirements of the target reaction system.

[0042] Furthermore, the reducing agent is isopropanol.

[0043] Furthermore, the mass-to-volume ratio of the squaric acid and the reducing reagent is 1 g: (35~50) mL.

[0044] Preferably, the thorough dispersion is ultrasonic dispersion.

[0045] Preferably, the time for sufficient dispersion is 5 to 30 minutes.

[0046] Furthermore, the mixing is ultrasonic mixing.

[0047] Preferably, the mixing time is 5 to 30 minutes.

[0048] Furthermore, the titanium source includes tetrabutyl titanate and / or tetraisopropyl titanate.

[0049] Furthermore, the titanium source is tetrabutyl titanate. MOF structures prepared using tetrabutyl titanate as the titanium source exhibit superior crystallinity compared to MOF structures prepared using other titanium sources.

[0050] Furthermore, as a preferred method, a titanium source is added to the mixed solution obtained in step Si, and the reaction system is kept under heating.

[0051] Furthermore, the mass ratio of the squaric acid to the titanium source is 1:(2~4).

[0052] Furthermore, the heating temperature is 40~60 ℃.

[0053] Furthermore, the heating duration is 5 to 20 minutes.

[0054] Furthermore, the temperature of the solvothermal reaction is 100~150 °C.

[0055] Furthermore, the solvothermal reaction takes 40-50 hours.

[0056] Furthermore, the post-processing includes cooling, washing, centrifugation, and drying.

[0057] Preferably, the solvent used for washing is isopropanol.

[0058] Preferably, the drying temperature is 25~50℃.

[0059] Preferably, the drying pressure is -0.1 to 1 MPa.

[0060] Preferably, the drying time is 12 to 48 hours.

[0061] This invention protects the application of the aforementioned S-type heterojunction composite catalyst in photocatalytic killing of microorganisms or photocatalytic degradation of organic pollutants.

[0062] This invention protects a method for photocatalytic killing of microorganisms, which involves adding the aforementioned S-type heterojunction composite catalyst to a system containing microorganisms and photocatalytically killing the microorganisms under full-spectrum light irradiation.

[0063] Furthermore, the microorganisms include one or more of bacteria, viruses, and fungi.

[0064] Furthermore, the bacteria include Gram-negative bacteria and / or Gram-positive bacteria.

[0065] Preferably, the Gram-negative bacteria include one or more of Escherichia coli, Pseudomonas aeruginosa, and Salmonella.

[0066] Preferably, the Gram-positive bacteria include one or more of Staphylococcus aureus, Streptococcus mutans, and Bacillus subtilis.

[0067] Furthermore, the virus includes one or more of influenza A virus, novel coronavirus, and adenovirus.

[0068] Furthermore, the fungi include one or more of Candida albicans, Aspergillus fumigatus, Aspergillus niger, and Aspergillus flavus.

[0069] Furthermore, the microorganism is bacteria.

[0070] Furthermore, the microorganism is a Gram-negative bacterium.

[0071] Preferably, the Gram-negative bacterium is Escherichia coli.

[0072] This invention protects a method for photocatalytic degradation of organic pollutants, which involves adding the aforementioned S-type heterojunction composite catalyst to a system containing organic pollutants and photocatalytically degrading the organic pollutants under full-spectrum light irradiation.

[0073] Further, the organic pollutants include antibiotics and / or dyes; preferably, the antibiotics include one or more of quinolone antibiotics, tetracycline antibiotics, and β-lactam antibiotics.

[0074] More preferably, the quinolone antibiotics include one or more of ciprofloxacin, norfloxacin, and enrofloxacin.

[0075] More preferably, the tetracycline antibiotics include one or more of tetracycline, chlortetracycline, and oxytetracycline.

[0076] More preferably, the β-lactam antibiotics include one or more of benzylpenicillin, ceftriaxone sodium, and imipenem.

[0077] Furthermore, the dyes include one or more of methylene blue, rhodamine B, and methyl orange. These dyes all contain chromophores or unsaturated bonds that are easily attacked by photoactive species (such as hydroxyl radicals), and therefore can also be efficiently degraded through photocatalysis.

[0078] Furthermore, the organic pollutant is an antibiotic.

[0079] Furthermore, the organic pollutant is a quinolone antibiotic.

[0080] Preferably, the quinolone antibiotic is ciprofloxacin.

[0081] This invention protects a photocatalyst composition comprising the aforementioned S-type heterojunction composite catalyst.

[0082] Compared with the prior art, the present invention has the following beneficial effects: This invention provides an S-type heterojunction composite catalyst, which mainly consists of squaric acid, titanium source, and Yb. 3+ and Er 3+ The catalyst was prepared using doped BiOBr nanosheets, with the mass percentage of BiOBr nanosheets ranging from 60% to 95%. The high specific surface area of ​​IEF-11 facilitates pollutant accumulation. The addition of these nanosheets expands the photoresponse range and acts as an electron trap, improving solar energy utilization and photocatalytic performance. The constructed S-shaped heterojunction promotes photogenerated carrier separation while retaining the strong redox capabilities of the composite system. This catalyst exhibits full-spectrum response, efficient degradation of organic pollutants, and inactivation of microorganisms, showing broad application prospects. Attached Figure Description

[0083] Figure 1 This is a transmission electron microscope image of the S-type heterojunction composite catalyst in Example 1.

[0084] Figure 2 The X-ray diffraction patterns are those of the S-type heterojunction composite catalysts in Example 1 and Comparative Example 2.

[0085] Figure 3 The diagram shows the ultraviolet diffuse reflectance (a), band gap (b), valence band (c), and band structure (d) of the S-type heterojunction composite catalyst in Example 1.

[0086] Figure 4 The graph shows the degradation efficiency of ciprofloxacin by the catalysts in Examples 1-2 and Comparative Examples 1-4 under visible light irradiation.

[0087] Figure 5 The graph shows the degradation efficiency of ciprofloxacin by the catalysts in Examples 1-2 and Comparative Examples 1-5 under full-spectrum light source irradiation.

[0088] Figure 6 The graph shows the degradation efficiency of ciprofloxacin in actual water bodies by the S-type heterojunction composite catalyst in Example 1 under natural light irradiation.

[0089] Figure 7 The figure shows the effect of the S-type heterojunction composite catalyst in Example 1 on the growth status of Escherichia coli on agar plates under different light source irradiation.

[0090] Figure 8 The graph shows the inactivation efficiency of the S-type heterojunction composite catalyst in Example 1 against Escherichia coli under different light source irradiation. Detailed Implementation

[0091] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0092] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0093] Figure 3 a is Figure 3 Figure a in the middle, Figure 3 b is Figure 3 In diagram b, the order follows the same pattern.

[0094] Example 1: Preparation of an S-type heterojunction composite catalyst S1. 137 mg Bi(NO3)3·5H2O (0.282 mmol), 20 mg Yb(NO3)3·5H2O (0.0445 mmol), and 15 mg Er(NO3)3·5H2O (0.0339 mmol) were dispersed in 30 mL of mannitol and stirred for 30 min to ensure homogeneity. Then, 34 mg KBr (0.0286 mmol) was slowly added while stirring, and stirring was continued for 15 min. Subsequently, the mixture was transferred to a hydrothermal reactor and subjected to a solvothermal reaction at 160 °C for 12 hours in a muffle furnace to obtain the precursor. After natural cooling, the precipitate was washed repeatedly with anhydrous ethanol and water, and dried. Finally, the precursor precipitate was calcined at 450 °C for 1 hour to obtain Yb. 3+ and Er 3+ Doped BiOBr nanosheets, i.e., BiOBr:Yb 3+ Er 3+ Nanosheets; S2. 191 mg of finely ground squaric acid solid powder was suspended in 8.2 mL of isopropanol and magnetically stirred at 450 rpm for 5 minutes at room temperature, followed by ultrasonic dispersion in a 35 kHz ultrasonic bath for 5 minutes; then 6.4 mL of glacial acetic acid and 1800 mg of BiOBr:Yb prepared according to step S1 were added. 3+ Er 3+ Nanosheets were further ultrasonically dispersed for 15 minutes. Then, 0.57 mL of tetrabutyl titanate (567.72 mg) was slowly added with stirring, and the temperature was raised to 50 °C and held at that temperature for 15 minutes to obtain an orange suspension. This orange suspension was transferred to a polytetrafluoroethylene-lined hydrothermal reactor and sealed. The temperature was increased to 120 °C at a rate of 1.5 °C / min and held at that temperature for 48 hours. Then, the temperature was lowered to room temperature at a rate of 1.5 °C / min, and an orange-brown solid precipitated. The orange-brown solid was washed with isopropanol, and then the solid was collected by centrifugation. The collected solid was dried under vacuum at 30 °C and 0.9 MPa for 12 hours to obtain the S-type heterojunction composite catalyst, namely IEF-11 / BiOBr:Yb. 3+ Er 3+ -90 S-type heterojunction catalyst; Among them, the S-type heterojunction composite catalyst contains BiOBr:Yb 3+ Er 3+ The catalyst has a nanosheet content of 90% by mass, hence it is named IEF-11 / BiOBr:Yb 3+ Er 3+ -90 S-type heterojunction catalyst.

[0095] Example 2: Preparation of an S-type heterojunction composite catalyst The difference from Example 1 is that in step S2, BiOBr:Yb 3+ Er 3+ The amount of nanosheets added was changed from 1800 mg to 800 mg; the BiOBr:Yb content in the S-type heterojunction composite catalyst was also changed. 3+ Er 3+ The catalyst comprises 80% nanosheets by mass, hence it is named IEF-11 / BiOBr:Yb 3+ Er 3+ -80 S-type heterojunction catalyst.

[0096] The other steps and conditions are the same as in Example 1.

[0097] Example 3: Preparation of an S-type heterojunction composite catalyst The difference from Example 1 is that in step S2, BiOBr:Yb 3+ Er 3+ The amount of nanosheets added was replaced from 1800 mg to 371 mg; the BiOBr:Yb content in the S-type heterojunction composite catalyst was also changed. 3+ Er 3+ The catalyst comprises 65% nanosheets by mass, hence it is named IEF-11 / BiOBr:Yb 3+ Er 3+ -65 S-type heterojunction catalyst.

[0098] The other steps and conditions are the same as in Example 1.

[0099] Comparative Example 1: Preparation of an S-type heterojunction composite catalyst The difference from Example 1 is that in step S2, BiOBr:Yb 3+ Er 3+ The amount of nanosheets added was replaced from 1800 mg to 40 mg; the BiOBr:Yb content in the S-type heterojunction composite catalyst was also changed. 3+ Er 3+ The nanosheets comprise 17% of the catalyst by mass, hence the catalyst is named IEF-11 / BiOBr:Yb. 3+ Er 3+ -17 S-type heterojunction catalyst.

[0100] The other steps and conditions are the same as in Example 1.

[0101] Comparative Example 2: Preparation of an S-type heterojunction composite catalyst The difference from Example 1 is that in step S2, BiOBr:Yb 3+ Er 3+The amount of nanosheets added was changed from 1800 mg to 100 mg; the BiOBr:Yb content in the S-type heterojunction composite catalyst was also changed. 3+ Er 3+ The nanosheets comprise 33% of the catalyst by mass, hence the catalyst is named IEF-11 / BiOBr:Yb. 3+ Er 3+ -33 S-type heterojunction catalyst.

[0102] The other steps and conditions are the same as in Example 1.

[0103] Comparative Example 3: Preparation of an IEF-11 catalyst 191 mg of finely ground squaric acid solid powder was suspended in 8.2 mL of isopropanol and magnetically stirred at 450 rpm for 5 minutes at room temperature, followed by ultrasonic dispersion in a 35 kHz ultrasonic bath for 5 minutes. Then, 0.57 mL of tetrabutyl titanate was slowly added with stirring, the temperature was raised to 50 °C, and kept at that temperature for 15 minutes to obtain an orange suspension. The orange suspension was transferred to a polytetrafluoroethylene-lined hydrothermal reactor and sealed. The temperature was increased to 120 °C at a rate of 1.5 °C / min and kept at that temperature for 48 hours. Then, the temperature was lowered to room temperature at a rate of 1.5 °C / min, and an orange-brown solid precipitated. The orange-brown solid was washed with isopropanol, and then the solid was collected by centrifugation. The collected solid was dried under vacuum at 30 °C and 0.9 MPa for 12 hours to obtain the IEF-11 catalyst.

[0104] Comparative Example 4: A BiOBr:Yb 3+ Er 3+ Preparation of nanosheet catalysts 137 mg Bi(NO3)3·5H2O, 20 mg Yb(NO3)3·5H2O, and 15 mg Er(NO3)3·5H2O were dispersed in 30 mL of mannitol and stirred for 30 min to ensure homogeneity. Then, 34 mg KBr was slowly added while stirring, and stirring was continued for 15 min. Subsequently, the mixture was transferred to a hydrothermal reactor and subjected to a solvothermal reaction at 160 °C for 12 hours in a muffle furnace to obtain the precursor. After natural cooling, the precipitate was washed repeatedly with anhydrous ethanol and water, and dried. Finally, the precursor precipitate was calcined at 450 °C for 1 hour to obtain Yb. 3+ and Er 3+ Doped BiOBr nanosheets, i.e., BiOBr:Yb 3+ Er 3+ Nanosheet catalyst.

[0105] Comparative Example 5: An IEF-11 / WO 3-x Preparation of -90 S-type heterojunction catalysts The preparation method, referring to Chinese patent application CN120054648A, specifically includes the following steps: 255 mg of finely ground squaric acid solid powder was suspended in 8.2 mL of isopropanol and magnetically stirred at 450 rpm for 5 minutes at room temperature, followed by sonication at 35 kHz in an ultrasonic bath for 5 minutes; then 6.4 mL of glacial acetic acid and 1800 mg of WO3 were added. 3-x The particles were sonicated again for 15 minutes. Then, 0.762 mL of tetrabutyl titanate was slowly added under stirring, and the mixture was heated at 50 °C for 15 minutes to obtain an orange suspension. The orange suspension was then transferred to a polytetrafluoroethylene-lined hydrothermal reactor and sealed. The temperature was increased to 120 °C at a rate of 1.5 °C / min and maintained for 48 hours. Finally, the temperature was decreased to room temperature at a rate of 1.5 °C / min to obtain an orange-brown solid. The orange-brown solid was washed with isopropanol, and then the solid was collected by centrifugation. The collected solid was vacuum dried at 0.9 MPa and 30 °C for 12 hours. Among them WO 3-x The particles were prepared by the following method: 50 mg WCl6 was dispersed in 50 mL methanol and stirred at room temperature for 30 minutes, then transferred to a hydrothermal reactor and subjected to a solvothermal reaction at 180 °C in a muffle furnace for 12 hours. Among them, WO 3-x In particles, 0 ≤ x < 1 (due to the presence of oxygen vacancies, WO3 is affected). 3-x In the crystal, the coordination number of W with O is ≤3). The WO 3-x The particles account for 90% of the total mass of the S-type heterojunction catalyst, therefore the catalyst is named IEF-11 / WO. 3-x -90 S-type heterojunction catalyst, and this catalyst can achieve a full-spectrum response.

[0106] Example 1: Structural Characterization of S-type Heterojunction Composite Catalyst Transmission electron microscopy (TEM) was used to examine the IEF-11 / BiOBr:Yb sample in Example 1. 3+ Er 3+ The -90 S-type heterojunction catalyst was characterized. Figure 1 The results showed that IEF-11 exhibited hexagonal small-faceted crystals. Figure 1 (Top right corner) According to statistical analysis using GM3 software, its crystal diameter is 85±30 nm. The stacked IEF-11 can transform BiOBr:Yb 3+ Er 3+ The nanosheets (100±20 nm in diameter) encapsulated the catalysts; the S-type heterojunction composite catalysts in Example 1 and Comparative Example 2 were characterized by X-ray diffraction (XRD). Figure 2XRD patterns showed that both exhibited IEF-11 and BiOBr:Yb. 3+ Er 3+ The typical characteristic peaks prove that the heterojunction has been successfully constructed, wherein BiOBr:Yb in Example 1 3+ Er 3+ The characteristic peaks of Example 1 are more significant compared to Comparative Example 2. Furthermore, the IEF-11 / BiOBr:Yb of Example 1... 3+ Er 3+ -90 UV diffuse reflectance of S-type heterojunction catalyst ( Figure 3 a) Band gap ( Figure 3 b) Price band ( Figure 3 c) and band structure data ( Figure 3 d) The results of the characterization above corroborate each other, which further confirms the successful construction of the S-type heterojunction in Example 1.

[0107] Experimental Example 2: Degradation Performance Test of Heterojunction Catalysts on Ciprofloxacin under Different Light Sources 1. Experimental Methods Prepare 100 mL of 10 mg / L ciprofloxacin (CIP) solution. Following the principle of "one solution corresponding to one sample," add 5 mg of the target sample (a single sample being the heterojunction catalyst of each embodiment or comparative example) to each of the multiple CIP solutions. Use a 300 W xenon lamp (equipped with a visible / full-spectrum reflector) as the light source and conduct experiments independently on each sample-containing system. First, place each system in the dark and stir for 30 minutes to achieve adsorption-desorption equilibrium between CIP and the corresponding catalyst surface. Then, turn on the light source and irradiate each system for 120 minutes, maintaining the temperature at 25 °C using condensate. Samples are taken periodically during irradiation. Take 3 mL of CIP solution from each sample system each time, remove the photocatalyst through a 0.22 μm aqueous filter membrane, and measure the CIP absorbance of the filtrate at the characteristic absorption wavelength of 271 nm using a UV spectrophotometer.

[0108] 2. Experimental Results The degradation efficiencies of each catalyst group for ciprofloxacin under visible light (420–800 nm) and full-spectrum conditions (200–2500 nm) are as follows: Figures 4-5 As shown. The results show that under visible light ( Figure 4 The degradation efficiency of the S-type heterojunction composite catalysts in Examples 1-2 was superior to that in Comparative Examples 1-4; under full-spectrum conditions ( Figure 5In Examples 1-2, the degradation efficiency of the S-type heterojunction composite catalysts was significantly better than that of Comparative Examples 1-5. Specifically, the efficiency of Examples 1-2 was 2.44-2.48 times that of Comparative Example 1, 1.95-1.99 times that of Comparative Example 2, 13.1-13.3 times that of Comparative Example 3, 1.25-1.27 times that of Comparative Example 4, and 8.23-8.36 times that of Comparative Example 5, fully demonstrating the superiority of the technical solution of this application. In Example 1, the IEF-11 / BiOBr:Yb... 3+ Er 3+ The -90 S-type heterojunction catalyst exhibited the best photocatalytic degradation performance, achieving a CIP degradation rate of 83.6% within 120 minutes under full-spectrum conditions. Given its superior performance, this example was selected as the representative sample, and subsequent tests will be conducted using it as the basis.

[0109] Furthermore, in Example 3, IEF-11 / BiOBr:Yb 3+ Er 3+ The degradation efficiency of the -65 S-type heterojunction catalyst is basically consistent with that of Examples 1-2, and is also better than that of Comparative Examples 1-5, so it will not be repeated here.

[0110] Experimental Example 3 IEF-11 / BiOBr:Yb 3+ Er 3+ -90 S-type heterojunction catalyst degradation performance of ciprofloxacin in real water bodies under natural light 1. Experimental Methods Measure 100 mL of actual water samples (sources include tap water, lake water, and domestic sewage) that have been allowed to stand and filter, and add 10 mg / L CIP to each sample. Following the principle of "one sample per water sample," add 5 mg of IEF-11 / BiOBr:Yb from Example 1 to each spiked water sample. 3+ Er 3+ -90S heterojunction catalyst; first, each system was stirred in the dark for 30 minutes to achieve adsorption-desorption equilibrium between CIP and the catalyst surface. Then, all systems were placed outdoors and irradiated with natural sunlight for 120 minutes (irradiation period: 11:30-13:30 in Guangzhou, China during summer). During the irradiation period, samples were taken periodically. For each sample system, 3 mL of reaction solution was taken each time. After removing the photocatalyst through a 0.22 μm aqueous filter membrane, the CIP absorbance of the filtrate was measured at the characteristic absorption wavelength of 271 nm using an ultraviolet spectrophotometer.

[0111] 2. Experimental Results In Example 1, IEF-11 / BiOBr:Yb 3+ Er3+ The degradation efficiency of the -90 S-type heterojunction catalyst in photocatalytic degradation of CIP in actual water bodies under natural sunlight (200~4000 nm) is as follows: Figure 6 As shown in the figure, the heterojunction catalyst achieved CIP degradation rates of 69%, 52.9%, 37%, and 36.2% in deionized water, tap water, lake water, and domestic sewage within 120 minutes, respectively. The degradation efficiency decreased significantly with increasing inorganic / organic matrix complexity in the water body. These results indicate that the heterojunction catalyst prepared in this invention exhibits good adaptability to photocatalytic degradation of CIP under actual water conditions and possesses practical application potential.

[0112] Experimental Example 4 IEF-11 / BiOBr:Yb 3+ Er 3+ -90 S-type heterojunction catalyst's photocatalytic bactericidal performance against E. coli 1. Experimental Methods Take 5 mL of E. coli ( E. coli ) Bacterial solution (OD) 600 =0.09~0.11), and mixed with 45 mL of sterile physiological saline to prepare a bacterial suspension; 20 mg of IEF-11 / BiOBr:Yb from Example 1 was added to the bacterial suspension. 3+ Er 3+ -90 S-type heterojunction catalyst, using a 300 W xenon lamp as the light source, was subjected to visible light (420~800 nm), near-infrared light (800~2500 nm), and full-spectrum light (200~2500 nm) conditions by using different filters. Samples were taken at 0, 15, 30, 45, and 60 minutes under each light source: 100 μL of bacterial suspension was taken and purified by 1×10⁻⁶... 3 After a 1:1 dilution, 80 μL of the diluted solution was evenly spread onto LB agar plates and incubated at 37 °C for 12–18 hours. The IEF-11 / BiOBr:Yb culture in Example 1 was evaluated by counting changes in E. coli colony counts. 3+ Er 3+ -90 The photocatalytic bactericidal properties of S-type heterojunctions.

[0113] 2. Experimental Results Figure 7 For different light source illumination, IEF-11 / BiOBr:Yb 3+ Er 3+-90 The effect of the S-type heterojunction catalyst on the growth state of E. coli on agar plates is shown in the figure. The results show that under visible light, near-infrared light, and full-spectrum light irradiation, this heterojunction catalyst has an effect on the growth state of E. coli on agar plates. E. coli The photocatalytic killing performance increases sequentially, confirming its excellent photocatalytic killing performance; correspondingly E. coli Quantitative analysis results of sterilization efficiency are as follows Figure 8 As shown, after irradiation with a near-infrared light source and a full-spectrum light source for 15 minutes, 20 mg of this heterojunction catalyst resulted in bacterial residue rates as low as 50% and 18%, respectively. Compared with the prior art CN120054648A, this application achieves a significant improvement in sterilization efficiency while reducing the amount of catalyst by 1 / 3. This dual advantage of "low dosage + high efficiency" further confirms the excellent photocatalytic sterilization performance of the heterojunction catalyst.

[0114] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An S-shaped heterojunction composite catalyst, characterized by, The S-type heterojunction composite catalyst is mainly prepared from squaric acid, a titanium source, Yb 3+ and Er 3+ doped BiOBr nanosheets; Yb 3+ and Er 3+ The mass ratio of the doped BiOBr nanosheet is 60% to 95%.

2. The S-type heterojunction composite catalyst according to claim 1, wherein, The Yb 3+ and Er 3+ The preparation method of the doped BiOBr nanosheet comprises the following steps: S1. mixing bismuth salt, ytterbium salt, erbium salt in organic solvent, adding bromide salt, carrying out solvothermal reaction, post-processing, obtaining precursor; S2. calcining the precursor obtained in step S1 at 300-500 ℃ to obtain the Yb 3+ and Er 3+ doped BiOBr nanosheets.

3. The S-type heterojunction composite catalyst according to claim 1, wherein The mass ratio of the squaric acid and the titanium source is 1: (2-4).

4. The method for preparing the S-type heterojunction composite catalyst according to any one of claims 1-3, characterized in that, The method comprises the following steps: Si. Yb 3+ and Er 3+ The BiOBr nanosheet doped with Yb, the acid reagent and the dispersion liquid containing squaric acid were mixed thoroughly to obtain a mixed solution. Sii. adding the titanium source into the mixed solution obtained in step Si, carrying out solvothermal reaction, post-processing, obtaining the S-type heterojunction composite catalyst.

5. Application of the S-type heterojunction composite catalyst in any one of claims 1-3 in photocatalytic killing of microorganisms or photocatalytic degradation of organic pollutants.

6. A method of photocatalytic killing of microorganisms, characterized by, The S-type heterojunction composite catalyst in any one of claims 1-3 is added into a system containing microorganisms, and microorganisms are photocatalytically killed under full-spectrum light irradiation.

7. The method of claim 6, wherein, The microorganisms include one or more of bacteria, viruses and fungi.

8. A method of photocatalytic degradation of organic pollutants, characterized in that, The S-type heterojunction composite catalyst in any one of claims 1-3 is added into a system containing organic pollutants, and the organic pollutants are photocatalytically degraded under full-spectrum light irradiation.

9. The method of claim 8, wherein, The organic pollutants include one or more of antibiotics and / or dyes; preferably, the antibiotics include one or more of quinolone antibiotics, tetracycline antibiotics and β-lactam antibiotics.

10. A photocatalyst composition characterized by, The photocatalyst composition includes the S-type heterojunction composite catalyst in any one of claims 1-3.

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