Ni-doped In2S3 / ZnMoO4 heterojunction material, and preparation method and application thereof

Abstract

The application discloses a kind of Ni doped In2S3 / ZnMoO4 heterojunction materials and preparation method and application thereof, belong to photocatalysis technical field.The Ni doped In2S3 / ZnMoO4 heterojunction material includes nanometer flower-like Ni doped In2S3, granular ZnMoO4;The granular ZnMoO4 is attached to nanometer flower-like Ni doped In2S3 surface;It is prepared by hydrothermal method, with the mode of loading ZnMoO4 and doping Ni.The activity of In2S3 photocatalyst is improved, the degradation of tetracycline is obviously improved, and the cycle stability is excellent;The Ni doped In2S3 / ZnMoO4 heterojunction material is not only simple to prepare, easy to operate, but also uses non-noble metal doping, which greatly reduces the preparation cost of photocatalyst.

Description

Technical Field

[0001] This invention belongs to the field of photocatalysis technology, specifically relating to a Ni-doped In2S3 / ZnMoO4 heterojunction material, its preparation method, and its application. Background Technology

[0002] Water resources are one of the most important material resources for human survival and development. At present, water pollution mainly comes from domestic water use and industrial wastewater. Among them, industrial wastewater is the main source of pollution. For example, antibiotic residues lead to the formation of a large number of organic pollutants in water bodies. These antibiotic residue organic pollutants are highly toxic and can pose a serious threat to human health. Therefore, finding effective ways to treat organic pollutants in water has become increasingly urgent.

[0003] Antibiotic pollutants mainly originate from pharmaceutical manufacturing enterprises, hospitals, and livestock farms. Tetracycline, as the most widely used antibiotic, has broad-spectrum antibacterial properties that are difficult to biodegrade. Once it enters water bodies, it will have a serious impact on human health. Treatment technologies for tetracycline antibiotics are not widely used in actual wastewater treatment processes, both domestically and internationally. Therefore, how to effectively remove tetracycline and develop new technologies has become a research hotspot. Currently, the most commonly used methods for removing tetracycline antibiotics include biological, physical, and chemical methods, but all have limited effectiveness in treating tetracycline antibiotics and are environmentally unfriendly.

[0004] Solar-driven photocatalytic degradation technology is one of the most promising methods to effectively address the energy crisis and environmental pollution. The process is green and environmentally friendly, and the photocatalyst can be recycled. However, the industrial application of photocatalytic degradation of organic matter is still limited by technology. First, photogenerated electrons and holes easily recombine, making it difficult to treat large quantities of industrial waste gas and wastewater. Second, the low utilization rate of solar energy greatly limits its use. Therefore, developing novel and efficient photocatalysts for organic matter degradation has become a current research hotspot.

[0005] Chinese patent document CN108126718A discloses a method for preparing an In2S3 / BiPO4 heterojunction photocatalyst and its application. This invention uses a heterojunction structure formed by spherical nanoparticles of In2S3 / BiPO4 for the degradation of tetracycline. The method uses a three-step process to prepare the In2S3 / BiPO4 heterojunction. First, single In2S3 and BiPO4 are synthesized, and then spherical nanoparticle In2S3 / BiPO4 heterojunction material is prepared by hydrothermal method. The preparation process is relatively cumbersome, and the spherical nanoparticles of In2S3 / BiPO4 heterojunction are prone to agglomeration, which is not conducive to the reaction on the material surface. The degradation rate of tetracycline is only 64% within 100 minutes, and the degradation effect is not ideal. This indicates that the problems of rapid recombination of photogenerated electrons and holes and low solar energy utilization have not been solved, and further improvement of the photocatalyst is still needed. Summary of the Invention

[0006] The purpose of this invention is to provide a Ni-doped In2S3 / ZnMoO4 heterojunction material, its preparation method, and its application, to solve the problems of easy recombination of photogenerated electrons and holes, low solar energy utilization, and low efficiency in the degradation of tetracycline in current photocatalytic degradation of organic pollutants.

[0007] To solve the above problems, the present invention adopts the following technical solution:

[0008] In a first aspect, a Ni-doped In2S3 / ZnMoO4 heterojunction material is provided, comprising nano-flower-shaped Ni-doped In2S3 and granular ZnMoO4; the granular ZnMoO4 is attached to the surface of the nano-flower-shaped Ni-doped In2S3; in the Ni-doped In2S3 / ZnMoO4 heterojunction material, the molar ratio of Ni to In is 0.03 to 0.15:1, the molar ratio of the nano-flower-shaped Ni-doped In2S3 to the granular ZnMoO4 is 1:0.5 to 1.2, the size of the nano-flower-shaped Ni-doped In2S3 is 5 to 8 μm, and the equivalent diameter of the granular ZnMoO4 is 50 to 200 nm.

[0009] Preferably, in the Ni-doped In2S3 / ZnMoO4 heterojunction material, the molar ratio of Ni to In is 0.09:1, and the molar ratio of the nano-flower-shaped Ni-doped In2S3 to the granular ZnMoO4 is 1:0.8.

[0010] Secondly, the present invention provides a method for preparing the above-mentioned Ni-doped In2S3 / ZnMoO4 heterojunction material, comprising the following steps:

[0011] S1. Dissolve InCl3·2H2O, thiourea, and Ni(NO3)2·6H2O in deionized water at a molar ratio of 1:2-4:0.03-0.15. Perform a hydrothermal reaction at 150-200℃ for 16-24 h, centrifuge at 2000-5000 rpm / min for 3-8 min, dry at 60-100℃ for 8-12 h, and calcine at 300-600℃ for 3-5 h to obtain nano-flower-like Ni-doped In2S3.

[0012] S2. Dissolve Zn(NO3)2·6H2O, Na2MoO4·2H2O and nano-flower-like Ni-In2S3 in deionized water, stir for 30-60 min, and then perform a hydrothermal reaction at 160-220℃ for 12-18 h. After centrifugation at 2000-5000 rpm / min for 3-8 min, dry at 60-100℃ for 8-12 h to obtain Ni-In2S3 / ZnMoO4 heterojunction material, i.e., Ni-doped In2S3 / ZnMoO4 heterojunction material.

[0013] Preferably, in step S2, the molar ratio of Zn(NO3)2·6H2O, Na2MoO4·2H2O and nano-flower-like Ni-In2S3 is 0.5~1.2:0.5~1.2:1.

[0014] Thirdly, the present invention applies the above-mentioned Ni-doped In2S3 / ZnMoO4 heterojunction material to the photocatalytic degradation of organic solutions containing tetracycline.

[0015] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0016] (1) The Ni-doped In2S3 / ZnMoO4 heterojunction material provided by the present invention uses 5-8 μm nanoflower-shaped Ni-doped In2S3 as the matrix and loads ZnMoO4 particles with a diameter of 50-200 nm to prepare a Ni-doped In2S3 / ZnMoO4 heterojunction photocatalyst with a large specific surface area of ​​35.52 m². 2 / g provides more active sites for the reaction, promoting surface redox reactions; its nanoflower-like hierarchical structure increases light reflection and scattering, extending the optical path and improving light energy utilization; the three-dimensional cross-linked structure inhibits the aggregation or shedding of nanounits, enhancing material stability; the close contact between nanosheets in the nanoflower-like structure can form efficient charge transport channels, improving charge separation efficiency and promoting effective charge separation; the constructed In2S3 / ZnMoO4 heterostructure can form an interfacial electric field, thereby achieving efficient migration and separation of photogenerated charges; Ni doping can form new doping energy levels, broadening the light absorption range, and can act as a trapping center, synergizing with the heterojunction to optimize the charge transport path and improve the efficiency of charge transfer. The improved separation efficiency of the charge enhances the photocatalytic degradation activity. The Ni-doped In₂S₃ / ZnMoO₄ heterojunction photocatalyst achieves a degradation rate of 86.7–94.6% for tetracycline at pH 7 under conditions of 25℃. In particular, when the molar ratio of Ni to In is 0.09:1 and the molar ratio of nano-flower-shaped Ni-doped In₂S₃ to granular ZnMoO₄ is 1:0.8, the prepared 0.09Ni-IS / 0.8ZM photocatalyst achieves a tetracycline degradation rate of 94.6%. Even after four cycles, the degradation rate remains at 86.7%, only decreasing by 8.4% compared to the first cycle. This indicates that the photocatalyst not only possesses high degradation activity but also excellent stability.

[0017] (2) The preparation method of the present invention uses thiourea as a sulfur source and template agent, and selects InCl3·2H2O as an indium source. Taking advantage of the high reactivity of InCl3·2H2O and thiourea, Ni-In2S3 with a nanoflower structure is prepared. The nanoflower structure can provide a larger specific surface area and provide abundant active sites for redox reactions on the material surface. The hierarchical arrangement of the nanoflower can increase light reflection and scattering, prolong the optical path, and improve the light energy utilization rate. The three-dimensional cross-linked structure inhibits the aggregation or shedding of nanounits and enhances the stability of the material. In addition, the close contact between the nanosheets of the nanoflower structure can form an efficient charge transport channel, improve the charge separation efficiency, and thus improve the photocatalytic activity.

[0018] (3) The preparation method of the present invention utilizes the advantages of Zn(NO3)2·6H2O and Na2MoO4·2H2O being inexpensive, readily available, highly stable, and with easily controllable morphology. These are combined with nano-flower-like Ni-In2S3 to construct an In2S3 / ZnMoO4 heterojunction, forming an interfacial electric field on the material surface. This field promotes electron-hole transfer under the influence of the interface, effectively suppressing electron-hole recombination and improving photocatalytic degradation performance. Furthermore, by doping with Ni, new doping energy levels can be formed, which not only expands the spectral response range of the semiconductor but also reduces electron-hole recombination. The energy required for the transition promotes the separation efficiency of photogenerated carriers and can also act as a capture center, working synergistically with the heterojunction to optimize the charge transport path and achieve effective charge separation. Experimental Example 2 tested the photocatalytic performance of Ni-IS / ZM, which achieved a degradation rate of 86.7% to 94.6% for tetracycline, which is 1.56 to 1.70 times and 3.64 to 3.97 times that of single In2S3 and ZnMoO4 photocatalysts, respectively. This indicates that the doping of Ni and the preparation of heterojunctions greatly improve the activity of single In2S3 and ZnMoO4 photocatalysts.

[0019] (4) The preparation method of the present invention synthesizes Ni-doped In2S3 / ZnMoO4 heterojunction material by conventional two-step hydrothermal method. The preparation method is simple and easy to operate, and the raw materials are inexpensive and widely available, which is conducive to industrial production.

[0020] (5) The Ni-doped In2S3 / ZnMoO4 heterojunction material prepared in this invention exhibits excellent stability in cyclic testing. In Experiment 4, the 0.09Ni-IS / 0.8ZM photocatalyst was subjected to four cyclic degradation experiments, and the final degradation rate of tetracycline was 86.7%, which was only 8.4% lower than the first degradation rate, indicating that the 0.09Ni-IS / 0.8ZM photocatalyst exhibits excellent stability. This is due to the three-dimensional cross-linked structure of 3D nanoflower-like In2S3, which enhances the mechanical strength of the material and reduces the shedding of active components. The construction of the heterojunction reduces hole accumulation and inhibits photocorrosion. Ni doping can also inhibit the S in In2S3. 2- The oxidation process can further improve the cycle stability of the photocatalyst.

[0021] (6) The Ni-doped In2S3 / ZnMoO4 heterojunction material prepared in this invention exhibits excellent photocatalytic degradation of tetracycline-containing organic solutions. Under the conditions of pH=7 and temperature of 25℃, the Ni-doped In2S3 / ZnMoO4 heterojunction material can achieve a degradation rate of 86.7% to 94.6% for tetracycline. Among them, the degradation rate of tetracycline by the 0.09Ni-IS / 0.8ZM photocatalyst is 94.6%. After four cycles of experiments, the degradation rate of tetracycline can still reach 86.7%, which is only 8.4% lower than the first cycle, indicating that the 0.09Ni-IS / 0.8ZM photocatalyst has better photocatalytic performance. Attached Figure Description

[0022] Figure 1 The image shows a SEM image of the Ni-In2S3 / ZnMoO4 heterojunction material prepared in Example 1, where 1 is a nano-flower-shaped Ni-doped In2S3 photocatalyst and 2 is a particulate ZnMoO4 attached to the surface of the nano-flower-shaped Ni-In2S3.

[0023] Figure 2 The elemental mapping diagram of the Ni-In2S3 / ZnMoO4 heterojunction material prepared in Example 1;

[0024] Figure 3 The N2 adsorption-desorption isotherm of the Ni-In2S3 / ZnMoO4 heterojunction material prepared in Example 1;

[0025] Figure 4 The degradation rate of tetracycline by the Ni-In2S3 / ZnMoO4 heterojunction material prepared in Example 5 at different pH values;

[0026] Figure 5 The image shows a cyclic test result of tetracycline degradation on the Ni-In2S3 / ZnMoO4 heterojunction material prepared in Example 5. Detailed Implementation

[0027] The present invention will be described in detail below with reference to the embodiments and comparative examples, but the present invention is not limited thereto. The values ​​in the synthetic samples in the embodiments and comparative examples all represent the content of the substances. For example, in the 0.03Ni-In2S3 / 0.5ZnMoO4 heterojunction material, 0.03 means that the molar ratio of Ni to In is 0.03:1, 0.5 means that the molar ratio of In2S3 to ZnMoO4 is 1:0.5, and so on. Example 1

[0028] (1) Dissolve 1.0 mmol of InCl3·2H2O, 2.5 mmol of thiourea and 0.03 mmol of Ni(NO3)2·6H2O in 70 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 160 °C for 22 hours. Then centrifuge at 2000 rpm / min for 8 min, dry at 60 °C for 12 h, and finally calcine at 400 °C for 4 hours to obtain nano-flower-like 0.03Ni-In2S3.

[0029] (2) Add 0.5 mmol of Zn(NO3)2·6H2O, 0.5 mmol of Na2MoO4·2H2O and 1.0 mmol of nano-flower-like 0.03Ni-In2S3 to 80 mL of deionized water, stir continuously for 40 minutes until completely dissolved, and then carry out hydrothermal reaction at 160 °C for 18 hours. Then centrifuge at 5000 rpm / min for 3 min and dry at 100 °C for 8 h to obtain 0.03Ni-In2S3 / 0.5ZnMoO4 heterojunction material, denoted as 0.03Ni-IS / 0.5ZM. Example 2

[0030] (1) Dissolve 1.0 mmol of InCl3·2H2O, 2.0 mmol of thiourea and 0.03 mmol of Ni(NO3)2·6H2O in 70 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 180 °C for 20 hours. Then centrifuge at 5000 rpm / min for 3 min, dry at 80 °C for 10 h, and finally calcine at 600 °C for 3 hours to obtain nano-flower-like 0.03Ni-In2S3.

[0031] (2) Add 0.8 mmol of Zn(NO3)2·6H2O, 0.8 mmol of Na2MoO4·2H2O and 1.0 mmol of nano-flower-like 0.03Ni-In2S3 to 80 mL of deionized water, stir continuously for 30 minutes until completely dissolved, and then carry out hydrothermal reaction at 180 °C for 16 hours. Then centrifuge at 3000 rpm / min for 8 min and dry at 70 °C for 11 h to obtain 0.03Ni-In2S3 / 0.8ZnMoO4 heterojunction material, denoted as 0.03Ni-IS / 0.8ZM. Example 3

[0032] (1) Dissolve 1.0 mmol of InCl3·2H2O, 4.0 mmol of thiourea and 0.03 mmol of Ni(NO3)2·6H2O in 70 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 150 °C for 24 hours. Then centrifuge at 4000 rpm / min for 4 min, dry at 100 °C for 8 h, and finally calcine at 500 °C for 4 h to obtain 0.03 Ni-In2S3 in the shape of nanoflowers.

[0033] (2) 1.2 mmol of Zn(NO3)2·6H2O, 1.2 mmol of Na2MoO4·2H2O and 1.0 mmol of nano-flower-like 0.03Ni-In2S3 were added to 80 mL of deionized water and stirred continuously for 50 minutes until completely dissolved. Then, a hydrothermal reaction was carried out at 220 °C for 12 hours. After that, the mixture was centrifuged at 2000 rpm / min for 7 min and dried at 80 °C for 10 h to obtain a 0.03Ni-In2S3 / 1.2ZnMoO4 heterojunction material, denoted as 0.03Ni-IS / 1.2ZM. Example 4

[0034] (1) Dissolve 1.0 mmol of InCl3·2H2O, 3.0 mmol of thiourea and 0.09 mmol of Ni(NO3)2·6H2O in 70 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 190 °C for 18 hours. Then centrifuge at 3000 rpm / min for 5 min, dry at 70 °C for 10 h, and finally calcine at 300 °C for 5 hours to obtain nano-flower-like 0.09Ni-In2S3.

[0035] (2) Add 0.5 mmol of Zn(NO3)2·6H2O, 0.5 mmol of Na2MoO4·2H2O and 1.0 mmol of nano-flower-like 0.09Ni-In2S3 to 80 mL of deionized water, stir continuously for 60 minutes, and after complete dissolution, carry out hydrothermal reaction at 200 °C for 14 hours, then centrifuge at 4000 rpm / min for 5 min, and dry at 60 °C for 12 h to obtain 0.09Ni-In2S3 / 0.5ZnMoO4 heterojunction material, denoted as 0.09Ni-IS / 0.5ZM. Example 5

[0036] (1) Dissolve 1.0 mmol of InCl3·2H2O, 3.5 mmol of thiourea and 0.09 mmol of Ni(NO3)2·6H2O in 70 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 200 °C for 16 hours. Then centrifuge at 5000 rpm / min for 4 min, dry at 90 °C for 11 h, and finally calcine at 400 °C for 3 hours to obtain nano-flower-like 0.09Ni-In2S3.

[0037] (2) Add 0.8 mmol of Zn(NO3)2·6H2O, 0.8 mmol of Na2MoO4·2H2O and 1.0 mmol of nano-flower-like 0.09Ni-In2S3 to 80 mL of deionized water, stir continuously for 80 minutes until completely dissolved, and then carry out hydrothermal reaction at 170 °C for 17 hours. Then centrifuge at 2000 rpm / min for 8 min and dry at 90 °C for 10 h to obtain 0.09Ni-In2S3 / 0.8ZnMoO4 heterojunction material, denoted as 0.09Ni-IS / 0.8ZM. Example 6

[0038] (1) Dissolve 1.0 mmol of InCl3·2H2O, 2.5 mmol of thiourea and 0.09 mmol of Ni(NO3)2·6H2O in 70 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 170 °C for 21 hours. Then centrifuge at 2000 rpm / min for 8 min, dry at 60 °C for 11 h, and finally calcine at 300 °C for 4 hours to obtain nano-flower-like 0.09Ni-In2S3.

[0039] (2) 1.2 mmol of Zn(NO3)2·6H2O, 1.2 mmol of Na2MoO4·2H2O and 1.0 mmol of nano-flower-like 0.09Ni-In2S3 were added to 80 mL of deionized water and stirred continuously for 70 minutes until completely dissolved. Then, a hydrothermal reaction was carried out at 190 °C for 15 hours. After that, the mixture was centrifuged at 3000 rpm / min for 6 min and dried at 70 °C for 10 h to obtain a 0.09Ni-In2S3 / 1.2ZnMoO4 heterojunction material, denoted as 0.09Ni-IS / 1.2ZM. Example 7

[0040] (1) Dissolve 1.0 mmol of InCl3·2H2O, 3.0 mmol of thiourea and 0.15 mmol of Ni(NO3)2·6H2O in 70 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 180 °C for 22 hours. Then centrifuge at 3000 rpm / min for 7 min, dry at 90 °C for 8 h, and finally calcine at 450 °C for 5 h to obtain nano-flower-like 0.15Ni-In2S3.

[0041] (2) Add 0.5 mmol of Zn(NO3)2·6H2O, 0.5 mmol of Na2MoO4·2H2O and 1.0 mmol of nano-flower-like 0.15Ni-In2S3 to 80 mL of deionized water, stir continuously for 90 minutes until completely dissolved, and then carry out hydrothermal reaction at 210 °C for 14 hours. Then centrifuge at 5000 rpm / min for 4 min and dry at 60 °C for 11 h to obtain 0.15Ni-In2S3 / 0.5ZnMoO4 heterojunction material, denoted as 0.15Ni-IS / 0.5ZM. Example 8

[0042] (1) Dissolve 1.0 mmol of InCl3·2H2O, 2.0 mmol of thiourea and 0.15 mmol of Ni(NO3)2·6H2O in 70 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 190 °C for 18 hours. Then centrifuge at 4000 rpm / min for 7 min, dry at 100 °C for 7 h, and finally calcine at 550 °C for 3 hours to obtain nano-flower-like 0.15Ni-In2S3.

[0043] (2) Add 0.8 mmol of Zn(NO3)2·6H2O, 0.8 mmol of Na2MoO4·2H2O and 1.0 mmol of nano-flower-like 0.15Ni-In2S3 to 80 mL of deionized water, stir continuously for 80 minutes until completely dissolved, and then carry out hydrothermal reaction at 220 °C for 13 hours. Then centrifuge at 3000 rpm / min for 5 min and dry at 80 °C for 12 h to obtain 0.15Ni-In2S3 / 0.8ZnMoO4 heterojunction material, denoted as 0.15Ni-IS / 0.8ZM. Example 9

[0044] (1) Dissolve 1.0 mmol of InCl3·2H2O, 4.0 mmol of thiourea and 0.15 mmol of Ni(NO3)2·6H2O in 70 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 160 °C for 23 hours. Then centrifuge at 5000 rpm / min for 6 min, dry at 80 °C for 10 h, and finally calcine at 500 °C for 4 hours to obtain nano-flower-like 0.15Ni-In2S3.

[0045] (2) 1.2 mmol of Zn(NO3)2·6H2O, 1.2 mmol of Na2MoO4·2H2O and 1.0 mmol of nano-flower-like 0.15Ni-In2S3 were added to 80 mL of deionized water and stirred continuously for 60 minutes. After complete dissolution, the mixture was subjected to hydrothermal reaction at 180 °C for 17 hours. Then, it was centrifuged at 4000 rpm / min for 7 min and dried at 100 °C for 8 h to obtain 0.15Ni-In2S3 / 1.2ZnMoO4 heterojunction material, denoted as 0.15Ni-IS / 1.2ZM. Comparative Example 1

[0046] 1.0 mmol of InCl3·2H2O and 2.5 mmol of thiourea were dissolved in 70 mL of deionized water. After complete dissolution, the mixture was subjected to a hydrothermal reaction at 160 °C for 22 hours. Then, it was centrifuged at 2000 rpm / min for 8 min, dried at 60 °C for 12 h, and finally calcined at 400 °C for 4 hours to obtain nano-flower-like In2S3. Comparative Example 2

[0047] 0.5 mmol of Zn(NO3)2·6H2O and 0.5 mmol of Na2MoO4·2H2O were added to 80 mL of deionized water and stirred continuously for 40 minutes until completely dissolved. The mixture was then subjected to a hydrothermal reaction at 160 °C for 18 hours. After centrifugation at 5000 rpm / min for 3 minutes, the mixture was dried at 100 °C for 8 hours to obtain ZnMoO4 nanoparticles. Comparative Example 3

[0048] 1.0 mmol of InCl3·2H2O, 2.5 mmol of thiourea, and 0.03 mmol of Ni(NO3)2·6H2O were dissolved in 70 mL of deionized water. After complete dissolution, the mixture was subjected to a hydrothermal reaction at 160 °C for 22 hours. Then, it was centrifuged at 2000 rpm / min for 8 min, dried at 60 °C for 12 h, and finally calcined at 400 °C for 4 h to obtain nano-flower-like 0.03Ni-In2S3, denoted as 0.03Ni-IS. Comparative Example 4

[0049] 1.0 mmol of InCl3·2H2O, 2.5 mmol of thiourea, and 0.2 mmol of Ni(NO3)2·6H2O were dissolved in 70 mL of deionized water. After complete dissolution, the mixture was subjected to a hydrothermal reaction at 160 °C for 22 hours. Then, it was centrifuged at 2000 rpm / min for 8 min, dried at 60 °C for 12 h, and finally calcined at 400 °C for 4 hours to obtain nano-flower-like 0.2Ni-In2S3, denoted as 0.2Ni-IS. Comparative Example 5

[0050] (1) Dissolve 1.0 mmol of InCl3·2H2O and 2.5 mmol of thiourea in 70 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 160 °C for 22 hours. Then centrifuge at 2000 rpm / min for 8 min, dry at 60 °C for 12 h, and finally calcine at 400 °C for 4 hours to obtain nano-flower-like In2S3.

[0051] (2) Add 0.5 mmol of Zn(NO3)2·6H2O, 0.5 mmol of Na2MoO4·2H2O and 1.0 mmol of nano-flower-like In2S3 to 80 mL of deionized water, stir continuously for 40 minutes until completely dissolved, and then carry out hydrothermal reaction at 160 °C for 18 hours. Then centrifuge at 5000 rpm / min for 3 min and dry at 100 °C for 8 h to obtain In2S3 / 0.5ZnMoO4 heterojunction material, denoted as IS / 0.5ZM. Comparative Example 6

[0052] (1) Dissolve 1.0 mmol of InCl3·2H2O, 2.5 mmol of thiourea and 0.03 mmol of Ni(NO3)2·6H2O in 70 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 160 °C for 22 hours. Then centrifuge at 2000 rpm / min for 8 min, dry at 60 °C for 12 h, and finally calcine at 400 °C for 4 hours to obtain nano-flower-like 0.03Ni-In2S3.

[0053] (2) Add 0.3 mmol of Zn(NO3)2·6H2O, 0.3 mmol of Na2MoO4·2H2O and 1.0 mmol of nano-flower-like 0.03Ni-In2S3 to 80 mL of deionized water, stir continuously for 40 minutes until completely dissolved, and then carry out hydrothermal reaction at 160 °C for 18 hours. Then centrifuge at 5000 rpm / min for 3 min and dry at 100 °C for 8 h to obtain 0.03Ni-In2S3 / 0.3ZnMoO4 heterojunction material, denoted as 0.03Ni-IS / 0.3ZM. Comparative Example 7

[0054] (1) Dissolve 1.0 mmol of InCl3·2H2O, 2.5 mmol of thiourea and 0.03 mmol of Ni(NO3)2·6H2O in 70 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 160 °C for 22 hours. Then centrifuge at 2000 rpm / min for 8 min, dry at 60 °C for 12 h, and finally calcine at 400 °C for 4 hours to obtain nano-flower-like 0.03Ni-In2S3.

[0055] (2) 1.5 mmol of Zn(NO3)2·6H2O, 1.5 mmol of Na2MoO4·2H2O and 1.0 mmol of nano-flower-like 0.03Ni-In2S3 were added to 80 mL of deionized water and stirred continuously for 40 minutes until completely dissolved. Then, a hydrothermal reaction was carried out at 160 °C for 18 hours. After that, the mixture was centrifuged at 5000 rpm / min for 3 min and dried at 100 °C for 8 h to obtain a 0.03Ni-In2S3 / 1.5ZnMoO4 heterojunction material, denoted as 0.03Ni-IS / 1.5ZM. Comparative Example 8

[0056] 1.0 mmol of InCl3·2H2O and 2.5 mmol of thioacetamide were dissolved in 70 mL of deionized water. After complete dissolution, the mixture was subjected to a hydrothermal reaction at 160 °C for 22 hours. Then, it was centrifuged at 2000 rpm / min for 8 min, dried at 60 °C for 12 h, and finally calcined at 400 °C for 4 hours to obtain nanosheet-like In2S3.

[0057] Experimental Example 1

[0058] Figure 1 This is a morphology image of the 0.03Ni-IS / 0.5ZM photocatalyst prepared in Example 1. Figure 1As can be seen in Figure 1, Ni-doped In₂S₃ photocatalyst with a nano-flower-like structure and a size of 5–8 μm is used. The nano-flower-like structure of Ni-In₂S₃ greatly increases the specific surface area of ​​the photocatalyst, providing more active sites for the reaction. Figure 2 shows particulate ZnMoO₄ attached to the surface of the Ni-In₂S₃ nano-flower-like structure with a diameter of 50–200 nm. The heterostructure formed by the Ni-In₂S₃ nano-flower-like structure and the particulate ZnMoO₄ can promote the separation of photogenerated electrons and holes, further enhancing the photocatalytic activity. Since the Ni content is relatively low and it is doped in the In lattice, it does not affect the overall morphology of the photocatalyst. By doping Ni and working synergistically with the heterostructure, the photocatalytic activity can be optimized. By improving the charge transport pathway of the catalyst and enhancing charge separation efficiency, the photocatalytic degradation activity is enhanced. The Ni-doped In₂S₃ / ZnMoO₄ heterojunction photocatalyst achieves a degradation rate of 86.7%–94.6% for tetracycline at pH 7 under conditions of 25℃. Specifically, when the molar ratio of Ni to In is 0.09:1 and the molar ratio of nano-flower-shaped Ni-doped In₂S₃ to granular ZnMoO₄ is 1:0.8, the degradation rate of tetracycline by the 0.09Ni-IS / 0.8ZM photocatalyst reaches 94.6%. Even after four cycles, the degradation rate remains at 86.7%, only decreasing by 8.4% compared to the first cycle, indicating that this photocatalyst exhibits high efficiency and stability in tetracycline degradation.

[0059] Figure 2 This shows the elemental distribution of the 0.03N-IS / 0.5ZM photocatalyst, from... Figure 2 It can be seen that the doped Ni is uniformly distributed in the 0.03Ni-IS / 0.5ZM photocatalyst, indicating that the 0.03Ni-IS / 0.5ZM photocatalyst was successfully prepared.

[0060] The photocatalytic performance of the photocatalysts prepared in Examples 1-9 and Comparative Examples 1-8 was evaluated. Tetracycline was used as the target pollutant for degradation. Tetracycline solutions with pH values ​​of 3, 5, 7, 9, and 11 were prepared. 30 mg of the photocatalyst was dispersed in 20 mg / L tetracycline solutions at different pH values ​​and stirred for 30 min in the dark to reach adsorption-desorption equilibrium between the pollutant and the photocatalyst. The photocatalytic reaction was then carried out under a 300 W xenon lamp and a 420 nm cutoff filter to ensure that the reaction was carried out under visible light irradiation. 5 mL of sample solution was collected every 20 min, and the tetracycline concentration was analyzed using a UV-Vis spectrophotometer.

[0061] Experimental Example 2

[0062] As shown in Table 1, the degradation rates of tetracycline by single In2S3 and ZnMoO4 photocatalysts were 55.7% and 23.8%, respectively, which were much lower than those of the 0.03Ni-IS / 0.5ZM photocatalyst. This is mainly due to the slow intrinsic electron migration rate and lack of an effective intrinsic electric field during the degradation process of single In2S3 and ZnMoO4 photocatalysts, which leads to rapid recombination of photogenerated electrons and holes. In addition, the limited light absorption range of single In2S3 and ZnMoO4 results in low light energy utilization, thus making the photocatalytic performance of single In2S3 and ZnMoO4 poor. Comparative Examples 3, 4 and 5 prepared 0. While 0.3Ni-IS, 0.2Ni-IS, and IS / 0.5ZM showed some improvement in tetracycline degradation compared to In2S3 alone, they still lagged significantly behind the 0.03Ni-IS / 0.5ZM photocatalyst. This indicates that Ni doping and the synergistic effect of the In2S3 / ZnMoO4 heterojunction can greatly improve the photocatalytic activity of the In2S3 matrix. However, judging from the tetracycline degradation rate of Comparative Example 4, excessive Ni doping may lead to an excessively high catalyst particle concentration, reducing the number of photocatalytic active sites and affecting the utilization of light energy, thereby reducing photocatalytic performance. Although Comparative Examples 6 and 7 utilized Ni... The photocatalysts prepared by doping and using In2S3 / ZnMoO4 heterojunctions achieved degradation rates of 75.2% and 78.3% for tetracycline, respectively, but these were still lower than the degradation rate of the 0.03Ni-IS / 0.5ZM photocatalyst. In the examples, Example 5 showed the highest degradation rate, reaching 94.6%. This indicates that excessive or insufficient ZnMoO4 loading affects the Ni-In2S3 / ZnMoO4 photocatalyst. Excessive ZnMoO4 loading covers the reactive sites on the In2S3 matrix surface. Since ZnMoO4 is mainly distributed on the In2S3 matrix surface, it is prone to aggregation, resulting in some active sites not being utilized. The limited reaction restricts the utilization of light by the Ni-In2S3 / ZnMoO4 photocatalyst. Insufficient ZnMoO4 loading results in an insignificant effect from the heterojunction, leading to insufficient improvement in photocatalytic activity. Comparative Example 8, which prepared nanosheet-like In2S3 without the addition of thiourea as a template agent, showed a degradation rate of 43.1%, significantly lower than that of the nanoflower-like In2S3 in Comparative Example 1. This indicates that the degradation performance of nanoflower-like In2S3 is superior to that of nanosheet-like In2S3. It also demonstrates that the nanoflower-like structure possesses a larger specific surface area, extended optical path, and efficient electron transport channels, which are beneficial for improving the performance of the photocatalyst.

[0063] The degradation rates of tetracycline by the photocatalyst materials in Examples 1-9 and Comparative Examples 1-8 at 25°C and pH 7 are shown in the table below:

[0064]

[0065] Experimental Example 3

[0066] Figure 3 The 0.03Ni-IS / 0.5ZM heterojunction material prepared in Example 1 was characterized by N2 adsorption / desorption (BET) analysis. The adsorption / desorption curves began to separate in the pressure region of approximately 0.36 (P / P0), showing a significant adsorption hysteresis loop, which corresponds to adsorption isotherm type IV. This indicates that the specific surface area of ​​the Ni-In2S3 / ZnMoO4 heterojunction material prepared in Example 1 is 35.52 m². 2 With a surface area of ​​ / g, its large specific surface area provides more active sites for the reaction, promotes the redox reaction on the surface, and thus effectively improves the performance of the photocatalyst.

[0067] Experiment Example 4

[0068] Figure 4 Example 5 illustrates the degradation rate of tetracycline at different pH values. The test results show that at 25°C and pH 5–9, the ratio of reaction solution concentration to initial concentration after tetracycline degradation by the 0.09Ni-IS / 0.8ZM photocatalyst is less than 20%, indicating that the 0.09Ni-IS / 0.8ZM photocatalyst exhibits good degradation performance under these conditions. Particularly at pH 7, the degradation rate of tetracycline by the 0.09Ni-IS / 0.8ZM photocatalyst reaches 94.6%, demonstrating the best degradation effect. This shows that strong acid and alkali environments significantly affect the tetracycline degradation performance of the 0.09Ni-IS / 0.8ZM photocatalyst. This is because tetracycline in strong acid solutions mainly exists as TC. + H exists in the form of + Will with TC + The formation of competitive adsorption relationships affects TC to some extent. + Contact with the photocatalyst affects the photocatalytic reaction activity; while in strongly alkaline solutions, tetracycline's TC mainly exists as TC4. - TC exists in the form of - It will generate electrostatic repulsion with the photocatalyst, thereby reducing the degradation rate of tetracycline.

[0069] Experimental Example 5

[0070] Stability is an important indicator for evaluating the performance of photocatalysts. Figure 5The figure shows the results of a cyclic degradation experiment of tetracycline using the 0.09Ni-IS / 0.8ZM photocatalyst at 25℃ and pH 7. The figure reveals that after four cycles of degradation (600 min total, 150 min per cycle), the degradation rate of tetracycline by the 0.09Ni-IS / 0.8ZM photocatalyst decreased slightly, but the fourth cycle achieved a degradation rate of 86.7%, maintaining high photocatalytic activity. Compared to the first degradation cycle, the rate decreased by only 8.4%, indicating excellent stability of the 0.09Ni-IS / 0.8ZM photocatalyst. This is mainly due to the three-dimensional cross-linked structure of the prepared 3D nanoflower-like In2S3, which not only enhances the mechanical strength of the material but also reduces the shedding of active components, thus making the 0.09Ni-IS / 0.8ZM photocatalyst structure more stable.

Claims

1. A Ni-doped In₂S₃ / ZnMoO₄ heterojunction material, characterized in that: The material comprises Ni-doped In2S3 in a nano-flower shape and granular ZnMoO4; the granular ZnMoO4 is attached to the surface of the Ni-doped In2S3 in a nano-flower shape; in the Ni-doped In2S3 / ZnMoO4 heterojunction material, the molar ratio of Ni to In is 0.03 to 0.15:1, the molar ratio of the Ni-doped In2S3 in a nano-flower shape to the granular ZnMoO4 is 1:0.5 to 1.2, the size of the Ni-doped In2S3 in a nano-flower shape is 5 to 8 μm, and the equivalent diameter of the granular ZnMoO4 is 50 to 200 nm.

2. The Ni-doped In₂S₃ / ZnMoO₄ heterojunction material according to claim 1, characterized in that, The Ni-doped In2S3 / ZnMoO4 heterojunction material has a Ni to In molar ratio of 0.09:1 and a nanoflower-shaped Ni-doped In2S3 to granular ZnMoO4 molar ratio of 1:0.

8.

3. A method for preparing the Ni-doped In₂S₃ / ZnMoO₄ heterojunction material as described in claim 1 or 2, characterized in that, Includes the following steps: S1. Dissolve InCl3·2H2O, thiourea and Ni(NO3)2·6H2O in deionized water at a molar ratio of 1:2~4:0.03~0.15, and perform hydrothermal reaction at 150~200℃ for 16~24h. After centrifugation and drying, calcine at 300~600℃ for 3~5h to obtain nano-flower-like Ni-In2S3, i.e., nano-flower-like Ni-doped In2S3. S2. Dissolve Zn(NO3)2·6H2O, Na2MoO4·2H2O and nano-flower-like Ni-In2S3 in deionized water, stir for 30-90 min, and hydrothermally react at 160-220℃ for 12-18 h. Centrifuge and dry to obtain Ni-In2S3 / ZnMoO4 heterojunction material, i.e., Ni-doped In2S3 / ZnMoO4 heterojunction material.

4. The method for preparing the Ni-doped In₂S₃ / ZnMoO₄ heterojunction material according to claim 3, characterized in that, In step S2, the molar ratio of Zn(NO3)2·6H2O, Na2MoO4·2H2O and nanoflower-like Ni-In2S3 is 0.5~1.2:0.5~1.2:

1.

5. An application of the Ni-doped In₂S₃ / ZnMoO₄ heterojunction material as described in claim 1 or 2, characterized in that, The Ni-doped In2S3 / ZnMoO4 heterojunction material was applied to the photocatalytic degradation of tetracycline-containing organic solutions.

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