A bimetallic sulfide heterojunction catalytic material and its synthesis method and application

Abstract

This invention discloses a bimetallic sulfide heterojunction catalytic material, its synthesis method, and application, belonging to the field of photocatalysis. The synthesis method involves dissolving Co(NO3)2·6H2O, Mn(CH3COO)2·4H2O, NaOH, and C2H5NS and performing a hydrothermal reaction to obtain the black material MnCo2S4. Bi(NO3)3·5H2O is dissolved in a nitric acid solution, and appropriate amounts of CTAB and Na2CO3 are added to ethylene glycol. The two solutions are mixed and subjected to a hydrothermal reaction to obtain Bi2O2CO3. MnCo2S4 and Bi2O2CO3 are dispersed in anhydrous ethanol and heated in a water bath until the solution completely evaporates, yielding the bimetallic sulfide heterojunction catalytic material Bi2O2CO3 / MnCo2S4. This photocatalytic system achieves effective pollutant degradation and features a simple synthesis method, good stability, and reusability.

Description

Technical Field

[0001] The present invention belongs to the field of photocatalysts, and in particular relates to a bimetallic sulfide heterojunction catalytic material, a synthesis method and an application thereof. Background Art

[0002] In recent years, photocatalytic technology has attracted considerable attention due to its environmentally friendly nature. Among various types of semiconductor catalysts, bismuth-based layered oxides (BiVO4, Bi2WO6, BiOX (X = Cl, Br, I, etc.)) represent a new class of photocatalysts with high stability and photocatalytic activity.

[0003] Bi2O2CO3 photocatalyst is a special one. It consists of alternating [Bi2O2] 2+ and CO3 2- Layer composition, with special properties associated with Aurivillius photocatalysts. The layered crystal structure brings an internal electric field and non-centrosymmetric polarization to Bi2O2CO3, which promotes the separation of photoinduced charges. It has a faster transport speed of photogenerated carriers and excellent photocatalytic performance. In addition, the anisotropy of the layered structure will promote the migration of photogenerated carriers along the surface of the material. At the same time, Bi2O2CO3 is an n-type semiconductor, and its positive valence band potential gives it stronger oxidation ability. However, pure Bi2O2CO3 can only respond to ultraviolet rays, so the photocatalytic performance is low, and the photogenerated charges can easily recombine rapidly in a single Bi2O2CO3.

[0004] In order to overcome the limitations of single-component Bi2O2CO3, various types of Bi2O2CO3-based heterojunctions have been proposed. The principle is to adjust the band gap engineering by introducing new energy levels in the band gap, thereby expanding the light absorption range and promoting charge migration. x S yDue to their tunable valence states, good conductivity, and abundant resources, they have become a class of materials for energy conversion applications such as supercapacitors, batteries, and electrocatalysts. Among these metal sulfides, cobalt sulfides have garnered increasing attention in photocatalytic reactions. Recent research progress has demonstrated that cobalt-based sulfides can effectively enhance the catalytic activity of photocatalysts. Compared to single cobalt-based sulfides, the bimetallic sulfide material MnCo2S4 offers advantages such as a narrow band gap, high conductivity, and strong optical absorption. This effectively extends the light absorption range into the visible light spectrum and enhances electron-hole separation in the heterojunction. The synergistic effect between the two metal ions enables them to exhibit stable and excellent catalytic activity, thereby promoting the efficient separation of photogenerated electron-hole pairs. The presence of Mn promotes multi-electron transfer, while Co, due to its high oxidation potential, enriches the redox active sites on the catalyst surface. Furthermore, MnCo2S4 exhibits a wide absorbance range and a large specific surface area, making it an ideal candidate for efficient charge transfer in photocatalysis. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for synthesizing a bimetallic sulfide heterojunction catalytic material to obtain a bimetallic sulfide heterojunction catalytic material with a simple preparation process, stronger visible light absorption, higher charge separation efficiency, better stability, reusability, and the ability to achieve photocatalytic degradation of organic pollutants.

[0006] Another object of the present invention is to provide a bimetallic sulfide heterojunction catalytic material.

[0007] Another object of the present invention is to provide an application of a bimetallic sulfide heterojunction catalytic material.

[0008] The technical solution of the present invention is: (one)

[0010] A method for synthesizing a bimetallic sulfide heterojunction catalytic material comprises the following steps:

[0011] A. Disperse Co(NO3)2·6H2O, Mn(CH3COO)2·4H2O, NaOH, and C2H5NS in deionized water and stir continuously until completely dissolved; then subject the solution to a hydrothermal reaction; after cooling to room temperature, collect the resulting product by centrifugation, wash with deionized water and anhydrous ethanol, and then dry in an oven to constant weight to obtain the black material MnCo2S4;

[0012] B. Dissolve an appropriate amount of Bi(NO3)3·5H2O in a nitric acid solution and continue to stir evenly. Simultaneously, in another beaker, add an appropriate amount of CTAB (cetyltrimethylammonium bromide) and Na2CO3 to ethylene glycol and continue to stir evenly. Then, mix the two solutions and stir to form a uniform suspension, and perform a hydrothermal reaction to obtain a white precipitate. Wash the precipitate with deionized water and ethanol, and then dry it in an oven to constant weight to obtain Bi2O2CO3.

[0013] C. Ultrasonic dispersion of a certain proportion of MnCo2S4 and Bi2O2CO3 into anhydrous ethanol, heating in a water bath, and continuously stirring until the solution is completely evaporated to obtain a bimetallic sulfide heterojunction catalytic material Bi2O2CO3 / MnCo2S4.

[0014] As a further improvement of the present invention, in step A, the molar ratio of Co(NO3)2·6H2O, Mn(CH3COO)2·4H2O, NaOH and C2H5NS is 2:1:6-9:3-5.

[0015] As a further improvement of the present invention, in step A, the temperature of the hydrothermal reaction is 140-180° C., and the time of the hydrothermal reaction is 10-14 h.

[0016] As a further improvement of the present invention, in step B, the molar ratio of Bi(NO3)3·5H2O, CTAB, and Na2CO3 is 5:1-2:40.

[0017] As a further improvement of the present invention, in step B, the temperature of the hydrothermal reaction is 160-200° C., and the time of the hydrothermal reaction is 10-14 h.

[0018] As a further improvement of the present invention, in step C, the mass ratio of MnCo2S4 to Bi2O2CO3 is 1:0.05-0.2.

[0019] As a further improvement of the present invention, in step C, the water bath heating temperature is 50-70°C.

[0020] The present invention combines Bi2O2CO3 material and MnCo2S4 material. The presence of Bi2O2CO3 solves the problem of unreasonable energy band position of single MnCo2S4 material, and MnCo2S4 enhances the visible spectrum absorption of Bi2O2CO3. The presence of S-type heterojunction effectively improves the efficiency of light capture and spatial interface separation, so that the bimetallic sulfide heterojunction material can efficiently degrade pollutants under the action of visible light. (two)

[0022] A bimetallic sulfide heterojunction catalytic material is prepared by the above-mentioned synthesis method of the bimetallic sulfide heterojunction catalytic material.

[0023] The energy band structures of Bi2O2CO3 and MnCo2S4 are staggered. Compared with the valence band of Bi2O2CO3 of about 1.40 eV and the conduction band of about -1.25 eV, the valence band position of MnCo2S4 is about 2.02 eV and the conduction band position is about -0.18 eV. The two can well construct an S-type heterojunction, promote the separation and migration of photogenerated carriers, and retain the original strong redox ability of both. (three)

[0025] Application of a bimetallic sulfide heterojunction catalytic material in photocatalytic degradation of organic pollutants.

[0026] Furthermore, the organic pollutants include bisphenol A.

[0027] The present invention synthesized a Bi2O2CO3 / MnCo2S4 S-type heterojunction, which can photodegrade organic pollutants such as bisphenol A under visible light irradiation. The bimetallic sulfide MnCo2S4 has unique electronic properties compared to traditional monometallic sulfide materials. The synergistic effect of the bimetallic ions effectively promotes the transfer of photogenerated electrons in the bulk phase, while the constructed S-type heterostructure allows the photogenerated electrons of MnCo2S4 to transfer across the heterojunction interface to Bi2O2CO3, reducing the recombination of electron-hole pairs. Ultimately, the composite material exhibits strong photocatalytic degradation activity. After visible light excitation, it reacts with water molecules and dissolved oxygen to generate a variety of active oxidizing species, effectively degrading pollutants in the aqueous phase.

[0028] The present invention has the following beneficial effects: By forming a heterojunction, the present invention combines Bi2O2CO3 and MnCo2S4 to create a bimetallic sulfide heterojunction catalytic material, Bi2O2CO3 / MnCo2S4, with enhanced charge separation, an absorption range covering the entire visible spectrum, and higher catalytic activity. Conventional single-component Bi2O2CO3 exhibits insufficient visible light absorption and prone to in-situ carrier recombination. While the bimetallic sulfide MnCo2S4 exhibits excellent optical absorption properties, with visible light absorption covering the entire visible spectrum, its conduction band position is not sufficiently negative, resulting in weak oxidation activity and difficulty reacting with water to form various reactive oxygen species. This results in poor photodegradation activity as a single material, and its application in the field of photocatalytic pollutant degradation is limited. The two have an interlaced energy band structure. By constructing a heterojunction to composite Bi2O2CO3 and the full-visible spectrum absorption material MnCo2S4, the photogenerated electron-hole pairs of the Bi2O2CO3 / MnCo2S4 composite photocatalytic nanomaterial are successfully separated at the heterojunction interface, avoiding the electron-hole recombination problem in the band gap of a single nanomaterial. The matching energy level position arrangement enables the two to accelerate the migration and separation of photogenerated charges. The construction of the heterojunction more effectively enhances the charge separation and electron transfer at the heterojunction interface, greatly improving the photocatalytic activity. At the same time, it makes up for the problems of insufficient visible light absorption of the single Bi2O2CO3 material and the unreasonable energy band position of the single MnCo2S4 material. Ultimately, the Bi2O2CO3 / MnCo2S4 photocatalytic system achieves effective pollutant degradation, and has the characteristics of simple synthesis method, good stability and reusability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a scanning electron microscope image of Bi2O2CO3 / MnCo2S4 prepared in Example 1 of the present invention;

[0030] Figure 2 Ultraviolet diffuse reflection absorption spectra of Bi2O2CO3 / MnCo2S4, MnCo2S4, and Bi2O2CO3 prepared in Example 1 and Comparative Examples 1 and 2 of the present invention;

[0031] Figure 3 Fourier transform infrared spectra of Bi2O2CO3 / MnCo2S4, MnCo2S4, and Bi2O2CO3 prepared in Example 1 and Comparative Examples 1 and 2 of the present invention;

[0032] Figure 4 This is a comparison chart of the photocatalytic degradation performance of Bi2O2CO3 / MnCo2S4, MnCo2S4, and Bi2O2CO3 prepared in Example 1 of the present invention and Comparative Examples 1 and 2;

[0033] Figure 5This is a comparison chart of the reusability experiment of Bi2O2CO3 / MnCo2S4 prepared in Example 1 of the present invention for photocatalytic degradation of bisphenol A. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below with reference to specific embodiments.

[0035] Example 1

[0036] A method for synthesizing a bimetallic sulfide heterojunction catalytic material comprises the following steps:

[0037] A. Disperse 2.0 mmol Co(NO3)2·6H2O, 1.0 mmol Mn(CH3COO)2·4H2O, 6.0 mmol NaOH, and 5.0 mmol C2H5NS in 80 mL deionized water and stir continuously at 600 r / min for 30 min until completely dissolved. The solution was then transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor and maintained at 160°C for 12 h for hydrothermal reaction. After cooling to room temperature, the product was collected by centrifugation, washed several times with deionized water and anhydrous ethanol, and then dried in an oven at 60°C to constant weight to obtain the black material MnCo2S4.

[0038] B. Dissolve 0.005 mol Bi(NO3)3·5H2O in 10 mL of 1 mol / L nitric acid solution and stir at 600 r / min for 30 min until uniform. Simultaneously, in another beaker, add 0.001 mol CTAB (cetyltrimethylammonium bromide) and 0.04 mol Na2CO3 to 60 mL of ethylene glycol and stir at 600 r / min for 30 min until uniform. Subsequently, mix the two solutions and magnetically stir at 600 r / min for 30 min to form a uniform suspension. Transfer the solution to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor and heat at 180°C for 12 h to perform a hydrothermal reaction to obtain a white precipitate. Wash the precipitate several times with deionized water and ethanol, then dry it in an oven at 60°C to constant weight to obtain Bi2O2CO3.

[0039] C. Ultrasonic dispersion of 100 mg MnCo2S4 and 20 mg Bi2O2CO3 in 20 mL of anhydrous ethanol was performed. The mixture was heated in a 50°C water bath and stirred continuously at 600 r / min until the solution was completely evaporated to obtain a bimetallic sulfide heterojunction catalytic material Bi2O2CO3 / MnCo2S4.

[0040] Figure 1This is a scanning electron microscope image of Bi2O2CO3 / MnCo2S4 prepared in this example. Figure 1 As shown, Bi2O2CO3 and MnCo2S4 nanosheets stacked on each other to form a layered nanosheet structure, which is conducive to the rapid transfer of photogenerated electrons between nanosheets.

[0041] Comparative Example 1

[0042] Prepare only MnCo2S4:

[0043] 2.0 mmol Co(NO3)2·6H2O, 1.0 mmol Mn(CH3COO)2·4H2O, 9.0 mmol NaOH and 3.0 mmol C2H5NS were dispersed in 80 mL deionized water and stirred continuously at 600 r / min for 45 min until completely dissolved; the solution was then transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor and maintained at 180 °C for 10 h for hydrothermal reaction; after cooling to room temperature, the obtained product was collected by centrifugation, washed several times with deionized water and anhydrous ethanol, and then dried in an oven at 60 °C to constant weight to obtain the black material MnCo2S4.

[0044] Comparative Example 2

[0045] Prepare only Bi2O2CO3:

[0046] 0.005 mol Bi(NO3)3·5H2O was dissolved in 10 mL of 1 mol / L nitric acid solution and stirred at 600 r / min for 40 min until homogeneous. Simultaneously, in another beaker, 0.0015 mol CTAB (hexadecyltrimethylammonium bromide) and 0.04 mol Na2CO3 were added to 60 mL of ethylene glycol and stirred at 600 r / min for 40 min until homogeneous. Subsequently, the two solutions were mixed and magnetically stirred at 600 r / min for 40 min to form a uniform suspension. The solution was transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor and heated at 160°C for 14 h for hydrothermal reaction to obtain a white precipitate. The precipitate was washed several times with deionized water and ethanol and then dried in an oven at 60°C to constant weight to obtain Bi2O2CO3.

[0047] Figure 2 The following are the ultraviolet diffuse reflection absorption spectra of Bi2O2CO3 / MnCo2S4, MnCo2S4 and Bi2O2CO3 prepared in Example 1 and Comparative Examples 1 and 2. Figure 2As shown, the light absorption cutoff edge of Bi2O2CO3 alone is approximately 375 nm, indicating weak visible light absorption, while MnCo2S4 exhibits full-spectrum absorption across the entire ultraviolet and visible light regions. For the Bi2O2CO3 / MnCo2S4 composite material, the addition of MnCo2S4 effectively improves the overall light absorption of the material, retaining the intensity of the material's absorption tail peak and significantly enhancing light absorption in the 400-800 nm absorption band, effectively improving the composite's visible light capture efficiency.

[0048] Figure 3 The Fourier transform infrared spectra of Bi2O2CO3 / MnCo2S4, MnCo2S4, and Bi2O2CO3 prepared in Example 1 and Comparative Examples 1 and 2 are shown. For Bi2O2CO3, 544 cm -1 The peak is generated by the CO stretching vibration of Bi2O2CO3, 821 cm -1 The narrow peak at 1411 cm -1 The broad peak near the 2- Asymmetric stretching vibrations. For MnCo2S4, at 465, 580 and 694 cm -1 The peaks at 983 and 1058 cm represent the combination of metal and sulfide, while the peaks at 983 and 1058 cm represent the combination of metal and sulfide. -1 The sharp peak at 2 is attributed to the vibration of sulfur ions in the lattice, which further confirms that S 2- The sample has a peak at 1507 cm -1 The broad absorption peak at is caused by the bending vibration of adsorbed water molecules. These characteristic spectra confirm the formation of MnCo2S4. At the same time, the main typical absorption peaks of the original Bi2O2CO3 and MnCo2S4 are present in the Bi2O2CO3 / MnCo2S4 sample, which further indicates the successful synthesis of the Bi2O2CO3 / MnCo2S4 composite catalyst.

[0049] Example 2

[0050] A method for synthesizing a bimetallic sulfide heterojunction catalytic material comprises the following steps:

[0051] A. Disperse 2.0 mmol Co(NO3)2·6H2O, 1.0 mmol Mn(CH3COO)2·4H2O, 6.0 mmol NaOH, and 3.0 mmol C2H5NS in 80 mL deionized water and stir continuously at 600 r / min for 60 min until completely dissolved. The solution was then transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor and maintained at 180°C for 10 h for hydrothermal reaction. After cooling to room temperature, the product was collected by centrifugation, washed several times with deionized water and anhydrous ethanol, and then dried in an oven at 60°C to constant weight to obtain the black material MnCo2S4.

[0052] B. Dissolve 0.005 mol Bi(NO3)3·5H2O in 10 mL of 1 mol / L nitric acid solution and stir at 600 r / min for 60 min until homogeneous. Simultaneously, in another beaker, add 0.0014 mol CTAB (cetyltrimethylammonium bromide) and 0.04 mol Na2CO3 to 60 mL of ethylene glycol and stir at 600 r / min for 60 min until homogeneous. Subsequently, mix the two solutions and magnetically stir at 600 r / min for 60 min to form a uniform suspension. Transfer the solution to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor and heat at 200°C for 10 h to perform a hydrothermal reaction to obtain a white precipitate. Wash the precipitate several times with deionized water and ethanol, then dry it in an oven at 60°C to constant weight to obtain Bi2O2CO3.

[0053] C. Ultrasonic dispersion of 100 mg MnCo2S4 and 5 mg Bi2O2CO3 in 20 mL of anhydrous ethanol was performed. The mixture was heated in a 60°C water bath and stirred continuously at 600 r / min until the solution was completely evaporated to obtain a bimetallic sulfide heterojunction catalytic material Bi2O2CO3 / MnCo2S4.

[0054] Example 3

[0055] A method for synthesizing a bimetallic sulfide heterojunction catalytic material comprises the following steps:

[0056] A. Disperse 2.0 mmol Co(NO3)2·6H2O, 1.0 mmol Mn(CH3COO)2·4H2O, 9.0 mmol NaOH, and 5.0 mmol C2H5NS in 80 mL deionized water and stir continuously at 600 r / min for 60 min until completely dissolved. The solution was then transferred to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor and maintained at 140°C for 14 h for hydrothermal reaction. After cooling to room temperature, the product was collected by centrifugation, washed several times with deionized water and anhydrous ethanol, and then dried in an oven at 60°C to constant weight to obtain the black material MnCo2S4.

[0057] B. Dissolve 0.005 mol Bi(NO3)3·5H2O in 10 mL of 1 mol / L nitric acid solution and stir at 600 r / min for 60 min until homogeneous. Simultaneously, in another beaker, add 0.002 mol CTAB (cetyltrimethylammonium bromide) and 0.04 mol Na2CO3 to 60 mL of ethylene glycol and stir at 600 r / min for 60 min until homogeneous. Subsequently, mix the two solutions and magnetically stir at 600 r / min for 60 min to form a uniform suspension. Transfer the solution to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor and heat at 160°C for 14 h to perform a hydrothermal reaction to obtain a white precipitate. Wash the precipitate several times with deionized water and ethanol, then dry it in an oven at 60°C to constant weight to obtain Bi2O2CO3.

[0058] C. Ultrasonic dispersion of 100 mg MnCo2S4 and 10 mg Bi2O2CO3 in 20 mL of anhydrous ethanol was performed. The mixture was heated in a 70°C water bath and stirred continuously at 600 r / min until the solution was completely evaporated to obtain a bimetallic sulfide heterojunction catalytic material Bi2O2CO3 / MnCo2S4.

[0059] (1) Evaluation of photocatalytic degradation performance

[0060] Bisphenol A photodegradation experiments were conducted on the photocatalysts Bi2O2CO3 / MnCo2S4, MnCo2S4, and Bi2O2CO3 prepared in Example 1 and Comparative Examples 1 and 2, respectively, to evaluate the photodegradation performance of the synthesized Bi2O2CO3 / MnCo2S4 photocatalyst under PMS activation. The method is as follows:

[0061] The photodegradation process was carried out in a 250 mL custom double-walled quartz beaker with a cooling water circulation system to maintain a constant reaction temperature. A 300 W xenon lamp was used as the light source with an average light intensity of 200 mW / cm 2. Before the reaction started, 50 mg of the photocatalyst was dispersed in a bisphenol A solution (10 mg / L, 100 mL), and the pH value was controlled at around 7 with 0.1 M hydrochloric acid or sodium hydroxide solution. The suspension was stirred continuously during the entire reaction process. A dark adsorption experiment was performed 30 minutes before illumination to achieve the adsorption-desorption equilibrium between bisphenol A and the photocatalyst. Then, 1 mM PMS (permonosulfate) was added. During the photodegradation process, 1 mL of the reaction solution was taken out at regular intervals and then passed through a 0.22 μm filter in preparation for ultra-high performance liquid chromatography analysis. The mobile phase was acetonitrile and ultrapure water (volume ratio of 50:50), and the detection wavelength was 278 nm. The relative concentration (C / C0) was used to calculate the degradation efficiency.

[0062] Figure 4 The performance comparison chart of Bi2O2CO3 / MnCo2S4, MnCo2S4 and Bi2O2CO3 prepared in Example 1 and Comparative Examples 1 and 2 for photocatalytic degradation of bisphenol A is shown in FIG. Figure 4 As shown, the experimental results show that under the conditions of catalyst dosage of 0.5 g / L, initial bisphenol A concentration of 10 mg / L and initial temperature of room temperature, the degradation efficiency of bisphenol A by single Bi2O2CO3 / PMS and MnCo2S4 / PMS systems were 26.21% and 68.08% respectively within 60 min, while the removal rate of bisphenol A by Bi2O2CO3 / MnCo2S4 / PMS system reached 98.65%, which means that the loading of MnCo2S4 enables the composite material to utilize more visible light. At the same time, the construction of S-type heterojunction effectively improves the interfacial charge transfer of photogenerated carriers and suppresses the in situ recombination of photogenerated electron-hole pairs in the two single photocatalysts.

[0063] The organic pollutants that can be degraded by the present invention include but are not limited to bisphenol A, atrazine, carbamazepine, tetracycline, rhodamine b, etc. Preferably, the Bi2O2CO3 / MnCo2S4 of the present invention has an exceptionally excellent degradation effect on bisphenol A under photocatalytic conditions. On the one hand, the photocatalytic material Bi2O2CO3 / MnCo2S4 is photoexcited to generate photogenerated electrons and photogenerated holes under visible light conditions. The matching energy level position enables the photogenerated electrons of the MnCo2S4 conduction band to be transferred across the heterojunction interface to the Bi2O2CO3 valence band. This S-type charge transfer mechanism not only promotes carrier separation, but also retains strong redox ability and promotes space charge transfer. On the other hand, in the presence of a polarizing electric field, the photogenerated electron-hole pairs on the surface of the MnCo2S4 material are further induced to continuously generate, significantly improving the charge separation efficiency.

[0064] (2) Continuous degradation experiment

[0065] After the first degradation reaction of the Bi2O2CO3 / MnCo2S4 prepared in Example 1 was completed, the reaction solution was centrifuged and washed, and the recovered Bi2O2CO3 / MnCo2S4 was dried in a freeze dryer for 48 hours and then placed back into the reactor for the next degradation experiment. Except for the materials, the other degradation reaction conditions were consistent with the setting procedures of the first photocatalytic degradation performance evaluation experiment; after the second reaction was completed, the above steps were repeated to perform three degradation experiments.

[0066] Figure 5 This is a comparison chart of the reusability of Bi2O2CO3 / MnCo2S4 photocatalytic degradation of bisphenol A prepared in Example 1. Figure 5 As shown, the degradation efficiency of bisphenol A was above 94% in three consecutive degradation experiments, which indicated that the photocatalytic activity of Bi2O2CO3 / MnCo2S4 photocatalytic nanomaterials remained good after three cycles.

Claims

1. A method for synthesizing a bimetallic sulfide heterojunction photocatalytic material, characterized by: The following steps are involved: A. Disperse Co(NO3)2·6H2O, Mn(CH3COO)2·4H2O, NaOH, and C2H5NS in deionized water and stir continuously until completely dissolved; then subject the solution to a hydrothermal reaction; after cooling to room temperature, collect the resulting product by centrifugation, wash with deionized water and anhydrous ethanol, and then dry in an oven to constant weight to obtain the black material MnCo2S4; B. Dissolve Bi(NO3)3·5H2O in nitric acid solution and continue stirring. Meanwhile, in another beaker, add CTAB and Na2CO3 to ethylene glycol and continue stirring. Subsequently, the two solutions were mixed and stirred to form a uniform suspension, and a hydrothermal reaction was performed to obtain a white precipitate. The precipitate was washed with deionized water and ethanol, and then dried in an oven to a constant weight to obtain Bi2O2CO3. C. Disperse MnCo2S4 and Bi2O2CO3 in anhydrous ethanol, heat in a water bath at a temperature of 50-70°C, and continue stirring until the solution is completely evaporated to obtain a bimetallic sulfide heterojunction catalytic material Bi2O2CO3 / MnCo2S4.

2. The method for synthesizing a bimetallic sulfide heterojunction photocatalytic material according to claim 1, characterized in that: In step A, the molar ratio of Co(NO3)2·6H2O, Mn(CH3COO)2·4H2O, NaOH and C2H5NS is 2:1:6-9:3-5.

3. The method for synthesizing a bimetallic sulfide heterojunction photocatalytic material according to claim 1, characterized in that: In step A, the hydrothermal reaction temperature is 140-180° C., and the hydrothermal reaction time is 10-14 h.

4. The method for synthesizing a bimetallic sulfide heterojunction photocatalytic material according to claim 1, characterized in that: In step B, the molar ratio of Bi(NO 3 ) 3 ·5H 2 O, CTAB, and Na 2 CO 3 is 5:1-2:

40.

5. The method for synthesizing a bimetallic sulfide heterojunction photocatalytic material according to claim 1, characterized in that: In step B, the temperature of the hydrothermal reaction is 160-200° C., and the time of the hydrothermal reaction is 10-14 h.

6. The method for synthesizing a bimetallic sulfide heterojunction photocatalytic material according to claim 1, characterized in that: In step C, the mass ratio of MnCo2S4 and Bi2O2CO3 is 1:0.05-0.

2.

7. A bimetallic sulfide heterojunction photocatalytic material, characterized by: The photocatalytic material is prepared by the synthesis method of a bimetallic sulfide heterojunction photocatalytic material according to any one of claims 1 to 6.

8. Use of the bimetallic sulfide heterojunction photocatalytic material according to claim 7 in photocatalytic degradation of organic pollutants.

9. The use of a bimetallic sulfide heterojunction photocatalytic material in photocatalytic degradation of organic pollutants according to claim 8, characterized in that: The organic pollutants include bisphenol A.

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