3D porous microspherical indium sulfide rich in sulfur vacancies as well as preparation method and application of 3D porous microspherical indium sulfide rich in sulfur vacancies

Abstract

The invention discloses 3D porous microspherical indium sulfide rich in sulfur vacancies as well as a preparation method and application thereof, and relates to the technical field of photocatalytic materials. Comprising the following steps that 1, indium chloride tetrahydrate and L-cysteine are dissolved and then stirred for the first time, a mixed solution is obtained, and the volume ratio of indium chloride tetrahydrate to L-cysteine is 1: (1.5-4.5); the invention discloses a preparation method of 3D porous indium sulfide.The preparation method of the 3D porous indium sulfide.The preparation method of the 3D porous indium sulfide.The preparation method of the 3D porous indium sulfide.The preparation method of the 3D porous indium sulfide.The preparation method of the 3D porous indium sulfide.The preparation method of the 3D porous indium sulfide.The preparation method of the 3D porous indium sulfide.The preparation method of the 3D porous indium sulfide.According to the preparation method of the 3D porous indium sulfide-3D porous indium sulfide-3D porous indium sulfide-3D porous indium sulfide-3D porous indium sulfide-3D porous indium sulfide-3D porous indium sulfide-3D porous indium sulfide-3D

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalytic materials, and in particular to a 3D porous microspherical indium sulfide rich in sulfur vacancies, a preparation method thereof, and an application thereof. Background Art

[0002] Over the past few decades, antibiotics have been widely used in human life. Tetracycline (TC), a typical broad-spectrum antibiotic, is highly stable but poorly biodegradable. If discharged directly into aquatic environments without effective treatment and purification, it is bound to cause unimaginable pollution to the ecological environment. Therefore, the search for efficient and environmentally friendly methods to remove TC has become a focus of current research. Photocatalysis, as an advanced oxidation technology, has opened up a new avenue for pollutant degradation due to its low cost, high efficiency, and environmentally friendly advantages.

[0003] Indium sulfide (In2S3) is a low-toxic III-VI semiconductor with a relatively narrow bandgap (2.0–2.3 eV), ensuring its efficient response to visible light. Furthermore, compared to other materials, In2S3 exhibits excellent photocorrosion resistance and good thermal stability, making it considered a very promising photocatalytic material. Despite this, the photocatalytic performance of pristine In2S3 photocatalysts remains unsatisfactory due to relatively slow carrier separation and migration kinetics. Therefore, modification or modification of pristine In2S3 is necessary to enhance its photocatalytic performance.

[0004] Recent reports have highlighted defect engineering as a promising strategy with great potential for improving photocatalytic performance. Defects can, on the one hand, provide low-valent metal centers and additional electrons for unsaturated ligand sites, promoting charge carrier separation and allowing electrons from the defect sites to transfer to the catalyst surface, generating more free radicals for pollutant degradation. On the other hand, these defects can provide more surface active sites, enhancing photocatalytic activity.

[0005] In general, common methods for constructing defects include plasma treatment, heteroatom doping, annealing, and chemical etching. However, these methods generally have certain disadvantages, including complex procedures, expensive or toxic precursors, and high energy consumption. Therefore, it is crucial to seek a simple, green, less toxic and low-cost method. Chinese patent CN115385373B discloses an indium zinc sulfide photocatalyst containing sulfur vacancies and zinc vacancies, and its preparation method and application. The ZnIn2S4 photocatalyst containing sulfur vacancies and zinc vacancies is synthesized by a solvent thermal method, and is prepared at 85-90°C by ultrasonic and stirring reactions to form a divacancy structure to improve carrier separation efficiency and band regulation. However, the preparation method uses thioacetamide as a sulfur source, which is highly toxic, and the sulfur vacancy concentration cannot be adjusted, resulting in poor photocatalytic performance. Summary of the Invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a 3D porous microspherical indium sulfide rich in sulfur vacancies and its preparation method and application, so as to solve the technical problems of the high toxicity and poor photocatalytic performance of indium sulfide obtained by the existing method of preparing indium sulfide by construction defects.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: The preparation method uses L-cysteine ​​as a sulfur source and reducing agent, synthesizes 3D porous microspherical indium sulfide through a simple one-step hydrothermal method, and applies it to the photocatalytic degradation of tetracycline in water.

[0008] The present invention is achieved through the following technical solutions: A method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies comprises the following steps: 1) dissolving indium chloride tetrahydrate and L-cysteine ​​and stirring for the first time to obtain a mixed solution, wherein the volume ratio of indium chloride tetrahydrate to L-cysteine ​​is 1:(1.5-4.5); 2) ultrasonically treating the mixed solution and then stirring it for the second time to obtain a hydrothermal precursor solution; 3) The hydrothermal precursor solution is subjected to high-temperature hydrothermal heating, cooled to room temperature, washed, and dried to obtain 3D porous microspherical indium sulfide.

[0009] Preferably, in step 1), the volume ratio of indium trichloride tetrahydrate to L-cysteine ​​is 1:3.5.

[0010] Preferably, in step 1), the first stirring time is 30 min to 60 min; and in step 2), the second stirring time is 15 min to 30 min.

[0011] Preferably, in step 2), the ultrasonic treatment is performed for 15 min to 30 min.

[0012] Preferably, in step 2), the ultrasonic treatment is performed for 30 minutes.

[0013] Preferably, in step 3), the high temperature hydrothermal temperature is 180° C.-200° C., and the time is 5 h-6 h.

[0014] Preferably, in step 3), the high temperature hydrothermal temperature is 180° C. and the time is 5 h.

[0015] Preferably, in step 3), ethanol and deionized water are used for centrifugal washing 3-5 times respectively.

[0016] Further preferably, in step 1), the tetrahydrated indium trichloride and L-cysteine ​​are dissolved in deionized water. Deionized water is free of metal ions (such as Ca 2+ Mg 2+ ) doping to ensure the stability of photocatalytic activity.

[0017] Further preferably, in step 2), the hydrothermal precursor solution is transferred to a reactor for high-temperature hydrothermal treatment. The sealed reactor maintains a high-pressure environment to promote the densification of the microsphere structure and enhance the mechanical strength.

[0018] The present invention also provides 3D porous microspherical indium sulfide rich in sulfur vacancies prepared by the above-mentioned preparation method of 3D porous microspherical indium sulfide rich in sulfur vacancies. The surface of the 3D porous microspherical indium sulfide is a porous structure formed by interlacing nanosheets to form a network. The size of the indium sulfide is 4μm-6μm.

[0019] The present invention also provides the use of the above-mentioned 3D porous microspherical indium sulfide rich in sulfur vacancies in the photocatalytic degradation of tetracycline.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies, wherein L-cysteine ​​is used as a sulfur source and reducing agent. L-cysteine ​​(containing -SH groups) is selected for its mild decomposition and reduction of highly toxic byproducts. By varying the dosage of L-cysteine, 3D porous microspherical indium sulfide rich in sulfur vacancies is obtained. Excessive L-cysteine ​​(>1.5 times) ensures the enrichment of sulfur vacancies and enhances the visible light response. When the volume ratio of indium trichloride tetrahydrate to L-cysteine ​​is >4.5, the microsphere structure collapses. When the volume ratio of indium trichloride tetrahydrate to L-cysteine ​​is <1.5 times, the vacancy concentration is insufficient. This range balances performance and morphology. This unique structure provides more reactive sites for the photocatalytic reaction of indium sulfide, thereby accelerating the synergistic process of pollutant adsorption-degradation and improving the photocatalytic performance. The reaction mechanism is that under visible light irradiation, indium sulfide produces e in the valence band. -, and then quickly migrate to the conduction band, leaving the same amount of h in the valence band + . Subsequently, these e - and h + Transfer to the catalyst surface to participate in the redox reaction. The difference is that when the prepared indium sulfide with sulfur vacancies is irradiated by visible light, the e in the valence band - will quickly migrate to the conduction band, and some of the e - When some electrons are captured by sulfur vacancies, the recombination of photogenerated carriers is effectively suppressed, and the energy barrier for interfacial charge transfer is lowered, thereby promoting more electrons to react with O2 adsorbed by sulfur vacancies, generating more active oxygen species and thus improving the photocatalytic performance.

[0021] Furthermore, indium sulfide prepared from indium trichloride tetrahydrate and L-cysteine ​​in a volume ratio of 1:3.5 introduced more sulfur defects and exhibited better O2 adsorption capacity, which indicates that the introduction of sulfur defects can effectively improve the adsorption of O2 and promote the activation of molecular oxygen.

[0022] Furthermore, the first stirring time ensures that the indium source is completely dissolved, and the second stirring time prevents particle agglomeration after ultrasound, thereby ensuring uniform size of the microspheres.

[0023] Furthermore, ultrasonication was performed for ≥15 min to break up the initial crystal nuclei and avoid large-sized particles; and for ≤30 min to prevent excessive breakage and damage to the self-assembly of microspheres.

[0024] Furthermore, limiting ultrasound to 30 minutes fully disrupts the molecular structure of L-cysteine, promoting the release of sulfur and forming controlled sulfur vacancies. Simultaneously, the ultrasonic energy uniformly mixes the indium and sulfur sources, preventing localized agglomeration and ensuring the final product is uniformly sized 3D porous microspheres (4–6 μm), enhancing the structural stability of the material.

[0025] Furthermore, the high-temperature hydrothermal temperature promotes the cleavage of L-cysteine-SH groups and generates sulfur vacancies in situ, and the high-temperature hydrothermal time prevents excessive grain growth from clogging the pores and maintains the porous structure.

[0026] Furthermore, the hydrothermal temperature and time jointly determine the morphology and porosity of the microspheres. Choosing 180°C and 5h can not only drive the self-assembly of nanosheets to form an interlaced network-like porous structure, but also avoid excessive growth of nanosheets or pore collapse caused by high temperature or long time. Experiments show that the indium sulfide prepared under these parameters provides more active sites for photocatalytic reactions. At the same time, sulfur vacancies act as electron capture centers to inhibit the recombination of photogenerated electrons and holes. The hydrothermal temperature of 180°C can stably form an appropriate amount of sulfur vacancies, while the reaction time of 5h ensures a uniform distribution of vacancies. Combined with the rapid mass transfer capability of the 3D porous structure, the separation efficiency of photogenerated carriers is significantly improved, thereby improving its poor photocatalytic performance.

[0027] Furthermore, ethanol is used to remove organic residues and water washing is used to remove ionic impurities, and the purity of the material is ensured 3-5 times.

[0028] The present invention also provides sulfur-vacancy-rich indium sulfide prepared by the above-mentioned preparation method, whose surface is composed of numerous loosely interlaced nanosheets, forming a network-like porous structure. Furthermore, sulfur defects are introduced into the indium sulfide by adjusting the dosage of L-cysteine. The introduction of sulfur defects and the unique morphology promote the adsorption of molecular oxygen on the indium sulfide surface and increase the transfer rate of photogenerated electrons to molecular oxygen, thereby effectively improving the generation efficiency of active species. Thanks to the efficient generation of active species, the photodegradation efficiency of tetracycline (TC) under visible light is significantly improved. Furthermore, indium sulfide can effectively capture free electrons, significantly inhibiting the recombination of photogenerated carriers, thereby improving photocatalytic reaction performance. Indium sulfide also enhances the adsorption of molecular oxygen and promotes the generation of superoxide radicals, thereby improving photocatalytic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the XRD pattern of indium sulfide prepared in Examples 1-4 of the present invention; Figure 2a This is a SEM image of indium sulfide prepared in Example 3 of the present invention, wherein Figure 2b for Figure 2a Magnified image of; Figure 2b An enlarged SEM image of indium sulfide prepared in Example 3 of the present invention; Figure 3 This is a HRTEM image of indium sulfide prepared in Example 3 of the present invention; Figure 4a The N2 adsorption-desorption isotherms and corresponding pore size distribution diagrams of indium sulfide prepared in Examples 1 and 3 of the present invention; Figure 4b The N2 adsorption-desorption isotherm and the corresponding pore size distribution diagram of indium sulfide prepared in Example 3 of the present invention; Figure 5 The EPR graphs of indium sulfide prepared in Example 1 and Example 3 of the present invention are as follows; Figure 6 The O2-TPD diagram of indium sulfide prepared in Example 1 and Example 3 of the present invention; Figure 7 This is a performance curve of the photocatalytic degradation of tetracycline by indium sulfide prepared in Examples 1-4 of the present invention. DETAILED DESCRIPTION

[0030] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0031] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0032] All features, such as values, amounts, contents, and concentrations, described herein as numerical ranges or percentage ranges are provided for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0033] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0034] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0035] The present invention is achieved through the following technical solutions: A method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies comprises the following steps: 1) Dissolving indium trichloride tetrahydrate and L-cysteine ​​in deionized water and stirring for the first time to obtain a mixed solution; 2) placing the mixed solution in an ultrasonic machine for sonication, followed by a second stirring step to obtain a hydrothermal precursor solution; 3) The hydrothermal precursor solution is transferred to a reactor for high-temperature hydrothermal treatment, cooled to room temperature, washed multiple times, and dried to obtain 3D porous indium sulfide.

[0036] Preferably, the indium trichloride tetrahydrate and L-cysteine ​​described in step 1) are dissolved in 60 mL-70 mL of deionized water at a volume ratio of 1:(1.5-4.5), and stirred for 30 mi-60 min to obtain a mixed solution.

[0037] Preferably, the mixed solution in step 2) is placed in an ultrasonic machine and ultrasonicated for 15-30 minutes and then stirred again for 15-30 minutes to obtain a hydrothermal precursor solution.

[0038] Preferably, in step 3), the hydrothermal precursor solution is transferred to a reactor and reacted at 180°C-200°C for 5-6 hours. After cooling to room temperature, the solution is washed by centrifugation with ethanol and deionized water for 3-5 times respectively, and then dried overnight to obtain 3D porous indium sulfide.

[0039] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0040] The following examples use conventional instruments and equipment in the art. Experimental methods in the following examples where specific conditions are not specified are generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, are conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" represents percentage by weight, "part" represents parts by weight, and "ratio" represents weight ratio.

[0041] Example 1 A method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies comprises the following steps: 1 mmol of indium trichloride tetrahydrate (InCl3·4H2O) and 1.5 mmol of L-cysteine ​​were added to 60 mL of deionized water and stirred for 30 minutes. The mixture was then sonicated for 30 minutes and stirred for an additional 15 minutes to achieve uniform dispersion. The resulting solution was then transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave and maintained at 180°C for 5 hours. After the reaction system cooled to room temperature, the product was washed three times with deionized water and anhydrous ethanol to remove any impurities and dried in vacuo at 60°C overnight. Subsequently, grinding yielded In2S3.

[0042] Example 2 A method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies comprises the following steps: 1 mmol of InCl₃·4H₂O and 2.5 mmol of L-cysteine ​​were added to 60 mL of deionized water and stirred for 30 minutes. The mixture was then sonicated for 30 minutes and stirred for an additional 15 minutes to achieve uniform dispersion. Finally, the solution was transferred to a 100 mL Teflon-lined stainless steel autoclave and maintained at 180°C for 5 hours. After the reaction system cooled to room temperature, the product was washed three times with deionized water and anhydrous ethanol to remove any impurities and dried in vacuo at 60°C overnight. Subsequently, grinding yielded In₂S₃-2.

[0043] Example 3 A method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies comprises the following steps: 1 mmol of InC l3 4H2O and 3.5 mmol of L-cysteine ​​were added to 60 mL of deionized water and stirred for 30 minutes. The mixture was then sonicated for 30 minutes and stirred for an additional 15 minutes to achieve uniform dispersion. Finally, the solution was transferred to a 100 mL Teflon-lined stainless steel autoclave and maintained at 180°C for 5 hours. After the reaction system cooled to room temperature, the product was washed three times with deionized water and anhydrous ethanol to remove any impurities and dried in vacuo at 60°C overnight. Subsequently, it was ground to yield In2S3-3.

[0044] Example 4 1 mmol of InCl₃·4H₂O and 4.5 mmol of L-cysteine ​​were added to 60 mL of deionized water and stirred for 30 minutes. The mixture was then sonicated for 30 minutes and stirred for an additional 15 minutes to achieve uniform dispersion. Finally, the solution was transferred to a 100 mL Teflon-lined stainless steel autoclave and maintained at 180°C for 5 hours. After the reaction system cooled to room temperature, the product was washed three times with deionized water and anhydrous ethanol to remove any impurities and dried in vacuo at 60°C overnight. Subsequently, grinding yielded In₂S₃-4.

[0045] Example 5 1 mmol of InCl₃·4H₂O and 4.5 mmol of L-cysteine ​​were added to 60 mL of deionized water and stirred for 60 minutes. The mixture was then sonicated for 15 minutes and stirred for an additional 30 minutes to achieve uniform dispersion. The resulting solution was then transferred to a 100 mL Teflon-lined stainless steel autoclave and maintained at 200°C for 5 hours. After the reaction system cooled to room temperature, the product was washed four times with deionized water and anhydrous ethanol to remove any impurities and dried in vacuo at 60°C overnight. Subsequently, grinding yielded In₂S₃-5.

[0046] Example 6 1 mmol of InCl₃·4H₂O and 4.5 mmol of L-cysteine ​​were added to 60 mL of deionized water and stirred for 43 minutes. The mixture was then sonicated for 22 minutes and stirred for an additional 23 minutes to achieve uniform dispersion. Finally, the solution was transferred to a 100 mL Teflon-lined stainless steel autoclave and maintained at 190°C for 5 hours. After the reaction system cooled to room temperature, the product was washed five times with deionized water and anhydrous ethanol to remove any impurities and dried in vacuo at 60°C overnight. Subsequently, grinding yielded In₂S₃-6.

[0047] Figure 1 The XRD patterns of the indium sulfide materials prepared in Examples 1-4 show that the prepared In2S3 samples exhibit typical characteristic peaks at 2θ of 14.2°, 23.3°, 27.4°, 33.2°, 43.6°, and 47.7°, which can be indexed to the (111), (220), (311), (400), (511), and (440) crystal planes of the cubic phase β-In2S3 (PDF#65-0459), respectively, indicating that indium sulfide was successfully prepared. In addition, no characteristic peaks of any other impurities were detected in the XRD patterns, indicating that the prepared In2S3 samples are of high purity.

[0048] Figure 2 is a SEM image of the indium sulfide material prepared in Example 3. Figure 2a It can be seen that the indium sulfide prepared in Example 3 is in the form of microspheres of 4-6 μm. Further magnification shows that the surface of the microsphere is composed of many loose nanowires, and these nanowires are intertwined to form a Figure 2b The network-like porous structure shown.

[0049] Figure 3 This is the HRTEM image of the indium sulfide material prepared in Example 3. From the image, lattice fringes of 0.322 nm and 0.263 nm can be clearly observed, corresponding to the (311) and (400) crystal planes of In2S3, respectively, further proving the successful preparation of In2S3.

[0050] Figure 4 shows the N2 adsorption-desorption isotherms and the corresponding pore size distribution of indium sulfide prepared in Examples 1 and 3. Figure 4a As shown, according to the IUPAC classification, the isotherms of the two samples are type IV isotherms, and the hysteresis loop range is between 0.45P / P0 and 0.95P / P0, indicating the presence of a typical mesoporous structure. Figure 4b The pore size distribution diagram shows that compared with In2S3, the pore size of In2S3-3 becomes smaller, but the porosity increases significantly.

[0051] Figure 5 The EPR patterns of indium sulfide prepared in Example 1 and Example 3 are shown. As can be seen from the figure, In2S3-3 exhibits a more obvious signal peak at g=2.004, which indicates that more sulfur defects are introduced.

[0052] Figure 6 The O2-TPD plots of indium sulfide prepared in Examples 1 and 3 are shown. As shown, both In2S3 and In2S3-3 exhibit desorption peaks between 250°C and 300°C, which can be attributed to chemically adsorbed oxygen. Compared to In2S3, In2S3-3 exhibits superior O2 adsorption capacity, indicating that the introduction of sulfur defects effectively enhances O2 adsorption and promotes the activation of molecular oxygen.

[0053] Photocatalytic degradation TC performance test process: Weigh 15 mg of samples from Examples 1-4 respectively, set up four experiments, and disperse the four samples in 50 mL TC (20 mg·L -1 ) solution. Stir in the dark for 60 minutes to reach adsorption-desorption equilibrium, and then, under constant magnetic stirring, irradiate the suspension with a 300WXe lamp equipped with a cutoff filter (λ>420nm) to start the photocatalytic degradation experiment. During the illumination process, 3 mL of the suspension was taken every 10 minutes and passed through a syringe filter (0.22μm) to obtain the supernatant. Finally, the supernatant was detected by a UV-visible spectrophotometer at a maximum wavelength of 357nm to analyze the change in TC concentration. Figure 7 As shown, compared with Examples 1, 2 and 4, the efficiency of the sample of Example 3 in photocatalytic degradation of TC is significantly improved.

[0054] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies, characterized in that: The following steps are involved: 1) dissolving indium chloride tetrahydrate and L-cysteine ​​and stirring for the first time to obtain a mixed solution, wherein the volume ratio of indium chloride tetrahydrate to L-cysteine ​​is 1:(1.5-4.5); 2) ultrasonically treating the mixed solution and then stirring it for the second time to obtain a hydrothermal precursor solution; 3) The hydrothermal precursor solution is subjected to high-temperature hydrothermal heating, cooled to room temperature, washed, and dried to obtain 3D porous microspherical indium sulfide.

2. The method for preparing a 3D porous microspherical indium sulfide rich in sulfur vacancies according to claim 1, characterized in that: In step 1), the volume ratio of indium trichloride tetrahydrate to L-cysteine ​​is 1:3.

5.

3. The method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies according to claim 1, characterized in that: In step 1), the first stirring time is 30 min to 60 min; in step 2), the second stirring time is 15 min to 30 min.

4. The method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies according to claim 1, characterized in that: In step 2), ultrasonic treatment is performed for 15 min to 30 min.

5. The method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies according to claim 4, characterized in that: In step 2), ultrasonic treatment was performed for 30 min.

6. The method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies according to claim 1, characterized in that: In step 3), the high temperature hydrothermal temperature is 180° C.-200° C., and the time is 5 h-6 h.

7. The method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies according to claim 6, characterized in that: In step 3), the high temperature hydrothermal temperature is 180° C. and the time is 5 h.

8. The method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies according to claim 1, characterized in that: In step 3), ethanol and deionized water are used for centrifugal washing 3-5 times respectively.

9. The 3D porous microspherical indium sulfide rich in sulfur vacancies prepared by the method for preparing 3D porous microspherical indium sulfide rich in sulfur vacancies according to any one of claims 1 to 8, characterized in that: The surface of the 3D porous micro-spherical indium sulfide is a network-like porous structure formed by interlacing nanosheets, and the size of the indium sulfide is 4 μm-6 μm.

10. Use of the 3D porous microspherical indium sulfide rich in sulfur vacancies according to claim 9 in photocatalytic degradation of tetracycline.

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