A template-based synthesis of ZnIn2S4 / Bi2S3 photocatalytic material, its preparation method, and its application.

Abstract

The application discloses a kind of ZnIn2S4 / Bi2S3 photocatalytic materials synthesized by template method and preparation method and application thereof, belong to photocatalytic technical field.The above-mentioned photocatalytic material is prepared by mild oil bath heating method one-pot with bismuth-based metal organic framework material as template.The photocatalytic material prepared by the method has close interface contact between monomers, and the Bi2S3 derived from metal organic framework material has high specific surface area and porosity, thereby effectively enhancing the separation of photo-generated carriers and oxygen adsorption;The photocatalytic material is used to catalyze oxygen reduction to produce hydrogen peroxide under pure water system and environmental air, has the advantages of simple preparation method, high visible light catalytic activity, provides an economic, green and sustainable way for hydrogen peroxide preparation.

Description

Technical Field

[0001] This invention relates to the field of photocatalysis technology, specifically to a template-synthesized ZnIn2S4 / Bi2S3 catalytic material for photocatalytic oxygen reduction to produce H2O2. Background Technology

[0002] Metal sulfide and metal oxide semiconductor materials are considered highly promising photocatalytic materials. Metal-organic frameworks (MOFs) are porous materials composed of metal centers or clusters linked to organic ligands via coordination bonds, and are considered ideal templates for preparing metal sulfides or oxides. Compared to metal sulfides or oxides prepared by conventional methods, those prepared using MOFs as templates possess higher specific surface area, porosity, and regular morphology. Furthermore, compared to MOFs, metal sulfides or oxides exhibit more stable structures and often possess narrower band gaps. Nevertheless, the prepared metal sulfides or oxides still face poor photogenerated carrier separation efficiency. Constructing heterojunctions by combining them with other semiconductors is an effective means to address these issues. However, in most cases, the method of constructing heterojunctions is stepwise, resulting in poor interfacial compatibility between heterojunction monomers. Designing a one-pot method for preparing heterojunctions could potentially achieve good interfacial compatibility, but this process still presents challenges.

[0003] Hydrogen peroxide (H2O2), as an environmentally friendly oxidant, possesses advantages such as strong oxidizing power, high operational safety, and a single byproduct (water), thus it is widely used in chemical production, wastewater treatment, and other industrial processes. Currently, H2O2 is mainly produced industrially via the anthraquinone oxidation method. This process requires high temperature and pressure conditions and generates a large amount of pollutants, which is inconsistent with the principles of green chemistry. Therefore, there is a need to develop a low-energy, green, and sustainable method for producing H2O2. In recent years, photocatalytic O2 reduction to H2O2 synthesis has been considered a highly promising strategy for small-scale H2O2 preparation. However, most current research requires alcohol solution systems and pure oxygen environments, which are costly and difficult to separate later. Therefore, developing a photocatalyst capable of efficiently preparing H2O2 in pure water systems and ambient air is of great significance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a catalytic material and its preparation method that can efficiently produce H2O2 by photocatalysis in pure water system and ambient air.

[0005] The technical solution of the present invention is to provide a photocatalytic material, characterized in that: the photocatalytic material is a ZnIn2S4 / Bi2S3 composite material synthesized in one pot using a bismuth-based MOF as a template, wherein the molar ratio of Bi2S3 to ZnIn2S4 in the ZnIn2S4 / Bi2S3 composite material is 0.25-0.75.

[0006] Preferably, the molar ratio of Bi2S3 to ZnIn2S4 is any one of 0.25∶1 (Example 1), 0.5∶1 (Example 2), and 0.75∶1 (Example 3).

[0007] The present invention also provides a method for preparing the above-mentioned photocatalytic material, comprising the following steps:

[0008] Step 1: Mix bismuth nitrate pentahydrate, ethylene glycol, and methanol to obtain a homogeneous solution A;

[0009] Step 2: Mix isophthalic acid with methanol to obtain a homogeneous solution B;

[0010] Step 3: Mix solution A and solution B and then carry out a solvothermal reaction at 110-130℃ in an oven for 18-30 hours to obtain bismuth-based MOF (CAU-17);

[0011] Step 4: Mix a certain mass of CAU-17 with deionized water, and sonicate and stir for more than 1 hour to form solution C;

[0012] Step 5, add ZnCl2 and I n Cl3·4H2O and thioacetamide were added to solution C;

[0013] Step 6: After adjusting the pH value of the mixed solution obtained in step 5 with hydrochloric acid, the solution is subjected to a hydrothermal reaction in an oil bath to obtain the photocatalytic material.

[0014] Specifically, in step 1, bismuth nitrate pentahydrate, ethylene glycol, and methanol are mixed to obtain a homogeneous solution A;

[0015] Step 2: Mix isophthalic acid with methanol to obtain a homogeneous solution B;

[0016] Step 3: Mix solution A and solution B and then perform a solvothermal reaction at 120°C in an oven for 24 hours to obtain CAU-17;

[0017] Step 4: Mix a certain amount of CAU-17 with deionized water, and sonicate and stir for 1 hour to form solution C;

[0018] Step 5: Add ZnCl2, InCl3·4H2O, and thioacetamide to solution C;

[0019] Step 6: After adjusting the pH value of the mixed solution obtained in step 5 with hydrochloric acid, the solution is subjected to a hydrothermal reaction in an oil bath to obtain the photocatalytic material.

[0020] In the above technical solution, the mass ratio of bismuth nitrate pentahydrate to isophthalic acid in steps 1 and 2 is 1:5;

[0021] In the above technical solution, the volume of ethylene glycol in step 1 is 5 mL.

[0022] In the above technical solution, the volume of methanol in steps 1 and 2 is 30 mL.

[0023] In the above technical solution, the molar ratio of ZnCl2, InCl3·4H2O and thioacetamide in step 5 is 1:2:6.

[0024] In the above technical solution, the concentration of hydrochloric acid in step 6 is 1 mol·L⁻¹. -1 In step 6, the pH value is adjusted to 2.5; the hydrothermal reaction temperature in step 6 is 80℃, and the hydrothermal reaction time is 6h.

[0025] This invention also provides applications of the above-mentioned photocatalytic material in reducing oxygen to prepare H2O2 under visible light, pure water systems, and ambient air.

[0026] Compared with the prior art, the present invention has the following advantages after adopting the above solution:

[0027] The ZnIn2S4 / Bi2S3 photocatalytic material prepared in a one-pot method using a bismuth-based metal-organic framework (MOF) exhibits close interfacial contact between monomers. Furthermore, the Bi2S3 derived from the MOF possesses a high specific surface area and porosity, effectively enhancing the separation of photogenerated carriers and oxygen adsorption, ultimately improving the catalytic activity of the photocatalyst. This material can be applied to the photocatalytic reduction of oxygen to H2O2 in pure water systems and under ambient air. The composite photocatalytic material provided by this invention combines Bi2S3 and ZnIn2S4 / Bi2S3... n2 The catalyst exhibited optimal performance when the molar ratio of S4 was 0.5:1, achieving a H2O2 yield of 995 μmol·L⁻¹ after 120 min of visible light irradiation. -1 . Attached Figure Description

[0028] Figure 1 a and b are X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectra of the ZnIn2S4 / Bi2S3 composite materials prepared in Examples 1-3, as well as ZnIn2S4, Bi2S3 and CAU-17, respectively.

[0029] Figure 2a and b are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the ZnIn2S4 / Bi2S3 composite material prepared in Example 2, respectively.

[0030] Figure 3 The graphs show the performance of the ZnIn2S4 / Bi2S3 composite materials prepared in Examples 1-3, as well as ZnIn2S4, Bi2S3, and CAU-17 in the photocatalytic reduction of oxygen to H2O2 under visible light, pure water system, and ambient air. Detailed Implementation

[0031] The present invention will be further described below with reference to specific embodiments:

[0032] Example 1

[0033] 150 mg of bismuth nitrate pentahydrate was added to a mixed solvent of 5 mL ethylene glycol and 30 mL methanol, and stirred for 40 min until completely dissolved, resulting in solution A. Simultaneously, 750 mg of isophthalic acid was added to 30 mL of methanol, and stirred for 30 min, resulting in solution B. Solution A was then slowly added dropwise to solution B, and the mixture was transferred to a 100 mL high-pressure reactor and maintained at 120 °C for 24 h. After cooling to room temperature, the sample was centrifuged, and the solid precipitate was washed with methanol and ethanol and then dried in a vacuum oven at 60 °C for 6 h to obtain CAU-17. 0.5 mmol of the above CAU-17 powder was added to 100 mL of deionized water, and after ultrasonication and stirring for 30 min, 137 mg of ZnCl2, 587 mg of InCl3·4H2O, and 451 mg of thioacetamide were added, followed by a reaction at 1 mol·L⁻¹. -1 The pH was adjusted to 2.5 with HCl. The reaction was then carried out in an oil bath at 80°C for 6 hours. Finally, the sample was centrifuged, and the solid precipitate was washed with water and ethanol and then dried in an oven at 80°C. This yielded the ZnIn2S4 / Bi2S3 composite material.

[0034] Example 2:

[0035] 150 mg of bismuth nitrate pentahydrate was added to a mixed solvent of 5 mL ethylene glycol and 30 mL methanol, and stirred for 40 min until completely dissolved, resulting in solution A. Simultaneously, 750 mg of isophthalic acid was added to 30 mL of methanol, and stirred for 30 min, resulting in solution B. Solution A was then slowly added dropwise to solution B, and the mixture was transferred to a 100 mL high-pressure reactor and maintained at 120 °C for 24 h. After cooling to room temperature, the sample was centrifuged, and the solid precipitate was washed with methanol and ethanol and then dried in a vacuum oven at 60 °C for 6 h to obtain CAU-17. 1 mmol of the above CAU-17 powder was added to 100 mL of deionized water, and after ultrasonication and stirring for 30 min, 137 mg of ZnCl2, 587 mg of InCl3·4H2O, and 451 mg of thioacetamide were added, and the mixture was then dissolved at 1 mol·L⁻¹. -1 The pH was adjusted to 2.5 with HCl. The reaction was then carried out in an oil bath at 80°C for 6 hours. Finally, the sample was centrifuged, and the solid precipitate was washed with water and ethanol and then dried in an oven at 80°C. This yielded the ZnIn2S4 / Bi2S3 composite material.

[0036] Figure 2 The images show SEM and TEM images of the ZnIn2S4 / Bi2S3 composite material prepared in Example 2. The ZnIn2S4 / Bi2S3 composite material prepared in Example 2 has a good and compact microstructure, which indicates that there is good interfacial contact between ZnIn2S4 and Bi2S3.

[0037] Example 3:

[0038] 150 mg of bismuth nitrate pentahydrate was added to a mixed solvent of 5 mL ethylene glycol and 30 mL methanol, and stirred for 40 min until completely dissolved, resulting in solution A. Simultaneously, 750 mg of isophthalic acid was added to 30 mL of methanol, and stirred for 30 min, resulting in solution B. Solution A was then slowly added dropwise to solution B, and the mixture was transferred to a 100 mL high-pressure reactor and maintained at 120 °C for 24 h. After cooling to room temperature, the sample was centrifuged, and the solid precipitate was washed with methanol and ethanol and then dried in a vacuum oven at 60 °C for 6 h to obtain CAU-17. 1.5 mmol of the above CAU-17 powder was added to 100 mL of deionized water, and after sonication and stirring for 30 min, 137 mg of ZnCl2, 587 mg of InCl3·4H2O, and 451 mg of thioacetamide were added, followed by a reaction at 1 mol·L⁻¹. -1 The pH was adjusted to 2.5 with HCl. The reaction was then carried out in an oil bath at 80°C for 6 hours. Finally, the sample was centrifuged, and the solid precipitate was washed with water and ethanol and then dried in an oven at 80°C. This yielded the ZnIn2S4 / Bi2S3 composite material.

[0039] Figure 1The XRD and FTIR spectra of the ZnIn2S4 / Bi2S3 composite materials prepared in Examples 1-3 are shown. It can be seen that CAU-17 has been completely converted into Bi2S3, and the ZnIn2S4 / Bi2S3 composite materials prepared in Examples 1-3 contain both ZnIn2S4 and Bi2S3.

[0040] The photocatalytic test conditions are as follows:

[0041] Photocatalytic H₂O₂ production test: Under room temperature and ambient air conditions, 20 mg of catalyst powder was dispersed in 40 mL of deionized water. The mixed solution was stirred in the dark for 30 min to ensure sufficient catalyst dispersion. The reaction solution was then placed under a 300 W xenon lamp (light wavelength range: 400-780 nm) equipped with a filter for photocatalytic reaction. During the photocatalytic reaction, samples were taken every 30 min, filtered through a 0.22 μm nylon 66 filter, and the filtrate samples were collected. The H₂O₂ concentration was determined at 350 nm using iodometric titration with a UV-Vis spectrophotometer.

[0042] The results of the examples show (e.g.) Figure 3 The composite photocatalyst material provided by this invention exhibits optimal catalyst performance when the molar ratio of Bi₂S₃ to ZnIn₂S₄ is 0.5:1, achieving a H₂O₂ yield of 995 μmol·L⁻¹ after 120 min of visible light irradiation. -1 .

[0043] This invention utilizes bismuth-based metal-organic framework materials as templates to prepare the aforementioned photocatalytic materials in a one-pot process via a mild oil bath heating method. The composite materials prepared by this method exhibit close interfacial contact between monomers, and the Bi₂S₃ derived from the metal-organic framework material possesses a high specific surface area and porosity, thereby effectively enhancing the separation of photogenerated carriers and oxygen adsorption. The photocatalytic materials are used to catalyze the reduction of oxygen to produce hydrogen peroxide under visible light, in pure water systems, and in ambient air. This method offers advantages such as simple preparation and high visible light catalytic activity, providing an economical, green, and sustainable pathway for H₂O₂ production.

[0044] The above description only illustrates preferred embodiments of the present invention and should not be construed as limiting the scope of the claims. Any equivalent structural or procedural modifications made using this specification are included within the patent protection scope of the present invention.

Claims

1. A photocatalytic material, characterized in that: The photocatalytic material is a ZnIn2S4 / Bi2S3 composite material synthesized in one pot using a bismuth-based metal-organic framework as a template. The molar ratio of Bi2S3 to ZnIn2S4 in the ZnIn2S4 / Bi2S3 composite material is 0.25-0.

75. The bismuth-based metal-organic framework material CAU-17 is prepared by solvothermal reaction using isophthalic acid as a ligand, and then the composite material is prepared by hydrothermal reaction with ZnCl2, InCl3·4H2O and thioacetamide.

2. The photocatalytic material according to claim 1, characterized in that: The molar ratio of Bi2S3 to ZnIn2S4 is any one of 0.25:1, 0.5:1, and 0.75:

1.

3. The method for preparing the photocatalytic material according to claim 1, characterized in that: Includes the following steps, Step 1: Mix bismuth nitrate pentahydrate, ethylene glycol, and methanol to obtain a homogeneous solution A; Step 2: Mix isophthalic acid with methanol to obtain a homogeneous solution B; Step 3: Mix solution A and solution B and then carry out a solvothermal reaction at 110-130℃ in an oven for 18-30 hours to obtain bismuth-based metal-organic framework material CAU-17; Step 4: Mix CAU-17 with deionized water, and sonicate and stir for more than 1 hour to form solution C; Step 5: Add ZnCl2, InCl3·4H2O, and thioacetamide to solution C; Step 6: After adjusting the pH value of the mixed solution obtained in step 5 with hydrochloric acid, the solution is subjected to a hydrothermal reaction in an oil bath to obtain the photocatalytic material.

4. The method for preparing the photocatalytic material according to claim 1, characterized in that: Includes the following steps, Step 1: Mix bismuth nitrate pentahydrate, ethylene glycol, and methanol to obtain a homogeneous solution A; Step 2: Mix isophthalic acid with methanol to obtain a homogeneous solution B; Step 3: Mix solution A and solution B and then perform a solvothermal reaction at 120°C in an oven for 24 hours to obtain CAU-17; Step 4: Mix CAU-17 with deionized water, and sonicate and stir for 1 hour to form solution C; Step 5: Add ZnCl2, InCl3·4H2O, and thioacetamide to solution C; Step 6: After adjusting the pH value of the mixed solution obtained in step 5 with hydrochloric acid, the solution is subjected to a hydrothermal reaction in an oil bath to obtain the photocatalytic material.

5. The method for preparing the photocatalytic material according to claim 4, characterized in that: The mass ratio of bismuth nitrate pentahydrate to isophthalic acid in steps 1 and 2 is 1:

5.

6. The method for preparing the photocatalytic material according to claim 4, characterized in that: The volume of ethylene glycol in step 1 is 5 mL.

7. The method for preparing the photocatalytic material according to claim 4, characterized in that: The volume of methanol in steps 1 and 2 is 30 mL.

8. The method for preparing the photocatalytic material according to claim 4, characterized in that: The molar ratio of ZnCl2, InCl3·4H2O and thioacetamide in step 5 is 1:2:

6.

9. The method for preparing the photocatalytic material according to claim 4, characterized in that: The concentration of hydrochloric acid in step 6 is 1 mol·L⁻¹. -1 In step 6, the pH value is adjusted to 2.5; the hydrothermal reaction temperature in step 6 is 80℃, and the hydrothermal reaction time is 6h.

10. The application of a catalyst prepared by the photocatalytic material as described in claim 1 or 2 or by the photocatalytic material preparation method as described in any one of claims 3-9 in the photocatalytic production of H2O2 in a pure water system and in ambient air.

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