Catalyst with bi-o / s mixed coordination structure and application thereof

Abstract

The application discloses a catalyst with a Bi-O / S mixed coordination structure and application thereof, and the catalyst comprises a sulfur indium zinc nanosheet and oxygen atoms and bismuth atoms doped in the sulfur indium zinc nanosheet. The application remarkably improves the efficiency of photocatalytic synthesis of hydrogen peroxide by doping a mixed coordination structure of bismuth-oxygen bonds and bismuth-sulfur bonds in the sulfur indium zinc nanosheet, and the catalyst can efficiently synthesize hydrogen peroxide without adding a sacrificial agent under deionized water and natural light.

Description

Technical Field

[0001] This invention relates to the field of photocatalytic materials technology, and more specifically, to a catalyst with a Bi-O / S mixed coordination structure and its application. Background Technology

[0002] Hydrogen peroxide (H2O2), as a green, environmentally friendly, and sustainable oxidant, has wide applications in environmental remediation, organic synthesis, energy conversion, and medical disinfection. Photocatalysis technology, by utilizing solar energy to drive the oxygen reduction reaction, can directly convert water and oxygen into H2O2, providing a highly promising pathway for the green synthesis of H2O2.

[0003] In related technologies, the catalytic efficiency of catalysts in photocatalysis is not high, and sacrificial agents such as alcohols are needed to improve the photocatalytic efficiency. However, adding sacrificial agents will lead to the complexity of the products and increase the difficulty of purifying H2O2.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The technical objective of this application is to address the above-mentioned shortcomings by providing a catalyst with a Bi-O / S mixed coordination structure and its application. This application significantly improves the efficiency of photocatalytic synthesis of hydrogen peroxide by doping bismuth-oxygen bonds and bismuth-sulfur bonds into zinc sulfide nanosheets. Moreover, the catalyst can efficiently synthesize hydrogen peroxide without the addition of sacrificial agents under deionized water and natural light.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] According to one aspect of this application, a catalyst having a Bi-O / S mixed coordination structure is provided, the catalyst comprising zinc indium sulfide nanosheets and oxygen atoms and bismuth atoms doped in the zinc indium sulfide nanosheets.

[0008] In some embodiments, the oxygen atom and the bismuth atom are doped into the indium sulfide nanosheet in the form of bismuth-oxygen bonds.

[0009] In some embodiments, the catalyst comprises a mixed coordination structure of bismuth-oxygen bonds and bismuth-sulfur bonds.

[0010] According to another aspect of this application, a method for preparing a catalyst with a Bi-O / S mixed coordination structure is also provided, comprising: weighing indium zinc sulfide nanosheets into deionized water and ultrasonically stirring until uniformly dispersed; adding 0.1 mol / L bismuth nitrate solution dropwise and stirring for 10 h; then adding 0.1 mol / L sodium borohydride solution dropwise and stirring for 0.5 h; allowing to stand for 0.5 h; taking the precipitate; and washing the precipitate with deionized water and anhydrous ethanol by vacuum filtration to obtain a catalyst with a Bi-O / S mixed coordination structure; wherein the ratio of the amount of indium zinc sulfide nanosheets, deionized water, bismuth nitrate solution and sodium borohydride solution added is 100 mg: 30 mL: 4.79 mL: 4.79 mL.

[0011] In some embodiments, the preparation method further includes, prior to the above steps: dissolving zinc acetate dihydrate, indium chloride tetrahydrate, and thioacetamide in a mixed solvent of anhydrous ethanol and deionized water to obtain a mixed solution; placing the mixed solution in a polytetrafluoroethylene-lined reactor, wherein the reaction temperature in the reactor is 180°C, and the reaction time in the reactor is 24 h, to obtain the zinc thioacetamide nanosheets; wherein the concentrations of zinc acetate dihydrate, indium chloride tetrahydrate, and thioacetamide in the mixed solvent are 0.0133 mol / L, 0.0267 mol / L, and 0.1067 mol / L, respectively, and the volume ratio of anhydrous ethanol to deionized water in the mixed solvent is 1:1.

[0012] According to another aspect of this application, a catalyst with a Bi-O / S mixed coordination structure or a method for preparing a catalyst with a Bi-O / S mixed coordination structure is also provided for the application of the catalyst with a Bi-O / S mixed coordination structure in the photocatalytic synthesis of hydrogen peroxide.

[0013] In some embodiments, the application involves synthesizing hydrogen peroxide in a body of water, wherein the water is one or more of deionized water, tap water, and river water.

[0014] In some embodiments, the photocatalytic light is the light from a 300W xenon lamp with an AM 1.5G filter.

[0015] In some embodiments, the light used for photocatalysis is outdoor natural sunlight.

[0016] Compared with existing technologies, the advantages and positive effects of this application are as follows: by introducing bismuth-oxygen co-doping sites, the separation efficiency of photogenerated carriers and the two-step single-electron oxygen reduction selectivity are significantly improved. BiO2S2 exhibits a high efficiency of 6054.67 μmol g in deionized water under AM 1.5G simulated sunlight. -1 h -1 The H2O2 formation rate and H2O2 selectivity are as high as 97%, demonstrating superior 2e- generation rate.- ORR activity.

[0017] Furthermore, the BiO2S2 catalyst has oxygen-coordinated bismuth single-atom sites, which further optimizes the adsorption characteristics of ORR intermediates in the active sites, thereby reducing the energy barrier for H2O2 generation.

[0018] Furthermore, the BiO2S2 catalyst can efficiently synthesize H2O2 in both deionized water and under natural sunlight. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 Transmission electron microscope (TEM) images of ZIS, BiO2S2, and BiS4 in Embodiments 1, 2, and the comparative examples of this application are shown.

[0021] Figure 2 The X-ray fine structure characterization of BiO2S2 in Example 2 of this application and BiS4 in the comparative example is shown.

[0022] Figure 3 Fourier transform infrared spectra of ZIS, BiO2S2, and BiS4 in Embodiments 1, 2, and the comparative examples of this application are shown.

[0023] Figure 4 The H2O2 production curve in Example 3 of this application is shown;

[0024] Figure 5 The following diagram shows the performance test results of BiO2S2 in different water bodies in Embodiment 4 of this application;

[0025] Figure 6 The diagram shows the performance test results of BiO2S2 under natural sunlight in Embodiment 5 of this application. Detailed Implementation

[0026] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

[0027] The present application will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1: Preparation of zinc indium sulfide (ZnIn2S4) nanosheets, the specific steps are as follows:

[0029] Zinc acetate dihydrate, indium chloride tetrahydrate, and thioacetamide (molar ratio 1:2:8) were dissolved in a mixed solvent of anhydrous ethanol and deionized water. The concentrations of zinc acetate dihydrate, indium chloride tetrahydrate, and thioacetamide in the mixed solvent were 0.0133 mol / L, 0.0267 mol / L, and 0.1067 mol / L, respectively. The volume ratio of deionized water to ethanol was 1:1, and the total volume was 60 mL, resulting in a mixed solution. The mixed solution was placed in a polytetrafluoroethylene-lined reactor, and the reaction temperature in the reactor was 180 °C for 24 h to obtain zinc indium sulfide nanosheets, abbreviated as ZIS.

[0030] Example 2: Preparation of a catalyst with a Bi-O / S mixed coordination structure, the specific steps are as follows:

[0031] Weigh 100 mg of the indium zinc sulfide nanosheets prepared in Example 1 into 30 mL of deionized water and ultrasonically stir until uniformly dispersed; add 4.79 mL of 0.1 mol / L bismuth nitrate solution dropwise and stir for 10 h; then add 4.79 mL of 0.1 mol / L sodium borohydride solution dropwise and stir for 0.5 h; let stand for 0.5 h; take the precipitate; and wash the precipitate with deionized water and anhydrous ethanol by vacuum filtration to obtain a catalyst with a Bi-O / S mixed coordination structure, abbreviated as BiO2S2.

[0032] Comparative example: The catalyst with Bi-S coordination structure was prepared by following specific steps:

[0033] Weigh 100 mg of the indium zinc sulfide nanosheets prepared in Example 1 into 30 mL of deionized water and ultrasonically stir until uniformly dispersed; add 4.79 mL of 0.1 mol / L bismuth nitrate solution (pH = 1) dropwise, and adjust the pH of the mixed solution with added bismuth nitrate solution to ensure that the pH = 1, stir for 10 h, let stand for 0.5 h, take the precipitate, and wash the precipitate with deionized water and anhydrous ethanol by vacuum filtration to obtain a catalyst with Bi-S coordination structure, abbreviated as BiS4.

[0034] It should be noted that in the comparative example, the bismuth nitrate solution needed to be pre-adjusted to pH ≤ 1, and the pH of the mixed solution containing the added bismuth nitrate solution was also adjusted to pH ≤ 1. pH control can inhibit the hydrolysis of bismuth nitrate to form BiS4. However, in Example 2, the added bismuth nitrate solution did not undergo pH adjustment, and the hydrolysis of bismuth nitrate would generate BiO. + Therefore, doping also includes entering the ZIS crystal structure in the form of Bi-O bonds.

[0035] Figure 1The transmission electron microscope (TEM) images of ZIS, BiO2S2, and BiS4 in Embodiments 1, 2, and the comparative examples of this application are shown below. Figure 1 As shown, ZIS, BiS4 and BiO2S2 all have nanosheet-like morphologies.

[0036] Figure 2 The X-ray fine structure (XAFS) characterization of Embodiment 2 (BiO2S2) and the comparative example (BiS4) of this application is shown, where 2a is the normalized X-ray fine structure near-edge structure spectrum (XANES) of the L-edge of Bi element, and 2b is the Fourier transform-X-ray extended edge structure spectrum (FT EXAFS). Figure 2 In a and 2b, Bi-foil represents Bi foil, Bi2O3 represents bismuth trioxide, and Bi2S3 represents bismuth sulfide. 2c shows the EXAFS fitting curve in R space for the comparative example (BiS4), and 2d shows the EXAFS fitting curve in R space for Example 2 (BiO2S2). Figure 2 In c and 2d, fit represents the fitted curve, Bi-S path represents Bi-S bonds, and Bi-O path represents Bi-O bonds. For example... Figure 2 As shown in the XANES spectrum, the valence state of Bi is between 0 and +3. In the EXAFS spectrum, the BiS4 catalyst exhibits... There is a main peak at this location, belonging to Bi-S coordination; the BiO2S2 catalyst is present at... There is a main peak at this location, belonging to Bi-S coordination. There is a low peak at the position, which belongs to Bi-O coordination; EXAFS fitting results show that the Bi-S coordination number in BiS4 is 3.7±0.2, and the Bi-O and Bi-S coordination numbers in BiO2S2 are 1.5±0.2 and 2.2±0.2, respectively.

[0037] Figure 3 The Fourier transform infrared (FT-IR) spectra of Embodiments 1, 2, and the comparative example of this application are shown. Figure 3 As shown, BiS4, BiO2S2 and ZIS have similar structures and do not cause significant changes.

[0038] Example 3: Comparison of H2O2 synthesis yield.

[0039] 5 mg each of ZIS obtained in Example 1, BiO2S2 obtained in Example 2, and BiS4 obtained in the comparative example were dispersed in 50 mL of deionized water to obtain dispersed liquids. Oxygen was bubbled into the dispersed liquids in the dark for 30 minutes to allow adsorption and desorption equilibrium to be reached. The reaction solution was then exposed to a 300 W xenon lamp equipped with an AM 1.5 G filter, with the light intensity set to 100 mW cm⁻¹. -2The illumination time was 60 minutes. The reaction temperature was controlled at 25°C using a stirrer and circulating water. The concentration of H₂O₂ in the water was measured over time using iodometric titration (with potassium iodide and potassium hydrogen phthalate as colorimetric reagents, showing an absorption peak at 350 nm).

[0040] Figure 4 The H2O2 production curve in Example 3 of this application is shown. Figure 4 As shown, the BiO2S2 catalyst exhibits the optimal H2O2 generation rate in pure water under simulated sunlight at AM 1.5G, reaching a high of 6054.67 μmol g. -1 h -1 The H2O2 formation rate of the BiS4 catalyst was 4441.33 μmol g. -1 h -1 The H2O2 formation rate of the ZIS catalyst was 1134.67 μmol g. -1 h -1 .

[0041] Example 4:

[0042] 5 mg of BiO2S2 obtained in Example 2 was dispersed in 50 mL of deionized water, tap water, and river water, respectively, to obtain dispersed liquids. Oxygen was bubbled into each of the dispersed liquids for 30 minutes under dark conditions to allow adsorption and desorption equilibrium to be reached. The reaction solution was then exposed to a 300 W xenon lamp equipped with an AM 1.5 G filter, with the light intensity set to 100 mW cm⁻¹. -2 The illumination time was 60 min, and the reaction temperature was controlled at 25℃ by stirring and circulating water. The H2O2 concentration in the water was measured over time using the iodometric method (potassium iodide and potassium hydrogen phthalate for color development, with an absorption peak at 350 nm).

[0043] Figure 5 The diagram shows the performance test results of BiO2S2 in different water bodies in Embodiment 4 of this application. Figure 5 As shown, the BiO2S2 catalyst exhibits a high H2O2 generation rate in deionized water, tap water, and river water under AM 1.5G simulated sunlight, indicating that the BiO2S2 catalyst has excellent activity.

[0044] Example 5:

[0045] 5 mg of BiO2S2 obtained in Example 2 was dispersed in 50 mL of deionized water to obtain a dispersed liquid. Oxygen was bubbled into the dispersed liquid for 30 minutes in darkness to allow it to reach adsorption-desorption equilibrium. The reaction system was then placed outdoors under natural sunlight for a photocatalytic reaction. The experimental location was E117°36'E, N39°11'N. The reaction started at 11:30 AM, and the light exposure time was 60 minutes. The measured natural light intensity during the reaction was approximately 50 mW / cm². -2 The concentration of H2O2 in water was measured over time using iodometric titration (with potassium iodide and potassium hydrogen phthalate for color development, showing an absorption peak at 350 nm).

[0046] Figure 6 The diagram shows the performance test results of BiO2S2 under natural sunlight in Embodiment 5 of this application. Figure 6 As shown, the H2O2 formation rate of the BiO2S2 catalyst under natural sunlight is 3692.44 μmol g. -1 h -1 .

[0047] Through the above specific embodiments, those skilled in the art can easily implement this application. However, it should be understood that this application is not limited to the specific embodiments described above. Based on the disclosed embodiments, those skilled in the art can arbitrarily combine different technical features to achieve different technical solutions.

Claims

1. A catalyst having a Bi-O / S mixed coordination structure, characterized in that, The catalyst comprises indium zinc sulfide nanosheets and oxygen and bismuth atoms doped in the indium zinc sulfide nanosheets; the oxygen and bismuth atoms are doped in the indium zinc sulfide nanosheets in the form of bismuth-oxygen bonds; the catalyst comprises a mixed coordination structure of bismuth-oxygen bonds and bismuth-sulfur bonds.

2. The method for preparing a catalyst with a Bi-O / S mixed coordination structure as described in claim 1, characterized in that, include: Weigh indium zinc sulfide nanosheets into deionized water and ultrasonically stir until uniformly dispersed. A 0.1 mol / L bismuth nitrate solution was added dropwise and stirred for 10 h. Then, a 0.1 mol / L sodium borohydride solution was added dropwise and stirred for 0.5 h. After standing for 0.5 h, the precipitate was collected and washed with deionized water and anhydrous ethanol by vacuum filtration to obtain a catalyst with a Bi-O / S mixed coordination structure. The ratio of indium sulfide nanosheets, deionized water, bismuth nitrate solution and sodium borohydride solution was 100 mg: 30 mL: 4.79 mL: 4.79 mL.

3. The method for preparing a catalyst with a Bi-O / S mixed coordination structure according to claim 2, characterized in that, The preparation method further includes, prior to: dissolving zinc acetate dihydrate, indium chloride tetrahydrate, and thioacetamide in a mixed solvent of anhydrous ethanol and deionized water to obtain a mixed solution; placing the mixed solution in a polytetrafluoroethylene-lined reactor, with a reaction temperature of 180°C and a reaction time of 24 hours, to obtain the zinc thioacetamide nanosheets; wherein the molar ratio of zinc acetate dihydrate, indium chloride tetrahydrate, and thioacetamide is 1:2:8, the concentrations of zinc acetate dihydrate, indium chloride tetrahydrate, and thioacetamide in the mixed solvent are 0.0133 mol / L, 0.0267 mol / L, and 0.1067 mol / L, respectively, and the volume ratio of anhydrous ethanol to deionized water in the mixed solvent is 1:

1.

4. The application of a catalyst with a Bi-O / S mixed coordination structure prepared by the method of preparing a catalyst with a Bi-O / S mixed coordination structure according to claim 1 or any one of claims 2-3 in the photocatalytic synthesis of hydrogen peroxide.

5. The application according to claim 4, characterized in that, The application involves synthesizing hydrogen peroxide in water, wherein the water is one or more of deionized water, tap water, and river water.

6. The application according to claim 4, characterized in that, The light used in the photocatalysis is from a 300 W xenon lamp with an AM 1.5G filter.

7. The application according to claim 4, characterized in that, The light used for photocatalysis is natural outdoor sunlight.

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