An In2S3 / In2MnS4 photoelectrocatalyst for the production of H2O2 or HClO and its preparation method

Abstract

This invention relates to an In2S3 / In2MnS4 photoelectrocatalyst for the production of H2O2 or HClO and its preparation method, belonging to the field of high-value-added chemicals and catalyst production technology. In2S3 hollow hierarchical microtubes are obtained through a solvothermal method, and Mn is converted into hydrogen through ion exchange. 2+ Partial exchange In 3+ An In2S3 / In2MnS4 photocatalyst was obtained. An In2S3 / In2MnS4 / PVDF / NF photocathode was obtained by loading In2S3 / In2MnS4 onto PVDF-modified nickel foam, and an In2S3 / In2MnS4 / CP photoanode was obtained by drop-coating In2S3 / In2MnS4 onto carbon paper. Under visible light irradiation and a specific additional bias voltage, the yields of H2O2 and HClO produced by the catalytic process reached 2107.8 μmol / L and 28.5 mg / L, respectively, within 90 min. This invention is simple, efficient, and low-cost, and can be applied to the photoelectric production of H2O2 and HClO.

Description

Technical Field

[0001] This invention belongs to the field of high value-added chemicals and catalyst production technology, specifically relating to an In2S3 / In2MnS4 photoelectrocatalyst for the production of H2O2 or HClO and its preparation method. Background Technology

[0002] Various semiconductor photocatalysts, including carbon nitrides, metal sulfides, and metal oxides, have been widely used in various photocatalytic reactions. However, due to their large band gaps and rapid electron-hole recombination, their catalytic ability is hindered. The formation of semiconductor heterojunctions is a common and effective solution. Their good band matching and excellent photoelectric properties can effectively promote charge separation and carrier transfer, improve charge transfer and photoelectric conversion efficiency, and greatly enhance the efficiency of photocatalysis and photoelectrochemistry. However, the preparation, separation, post-processing, and recycling of semiconductor heterojunction materials present certain difficulties. In2S3 has attracted widespread attention due to its good photosensitivity and photoconductivity, stable chemical and physical properties, and low toxicity. Therefore, this invention uses a simple oil bath-solvothermal-ion exchange method to prepare In2S3 and In2MnS4 composite semiconductor materials, constructing an In2S3 / In2MnS4 heterojunction composite photocatalyst for the photoelectrocatalytic production of H2O2 and HClO.

[0003] H₂O₂ is one of the most attractive chemical substances in the energy and environmental fields, widely used in pulp and textile bleaching, emergency medicines, and advanced wastewater oxidation processes. Besides being a valuable clean environmental remediation oxidant, H₂O₂ can also be used as a liquid fuel. Anodic electrolysis of NaCl solution has advantages such as mild reaction conditions and low raw material costs, while HClO is a commonly used chemical in bleaching and industrial wastewater treatment. Photoelectrocatalysis combines the advantages of photocatalysis and electrocatalysis, achieving higher solar energy conversion efficiency than photocatalysis while significantly reducing energy consumption compared to electrocatalysis, thus offering greater application value. Summary of the Invention

[0004] One objective of this invention is to provide a hollow hierarchical tubular In2S3 / In2MnS4 S-type heterojunction photoelectrocatalyst with visible light response and capable of effectively separating photogenerated electrons and holes, and its preparation method.

[0005] The second objective of this invention is to provide a method for producing H2O2 and HClO using a hollow, hierarchical tubular In2S3 / In2MnS4 S-type heterojunction photoelectrochemical catalyst.

[0006] The technical solution adopted in this invention is:

[0007] An In2S3 / In2MnS4 photoelectrocatalyst for the production of H2O2 or HClO is obtained by synthesizing MIL-68(In) from In(NO3)3·xH2O and H2BDC via oil bath reflux, sulfiding MIL-68(In) to In2S3 via a solvothermal method, and partially exchanging In2S3 to In2MnS4 via an ion exchange method, thus obtaining the In2S3 / In2MnS4 S-type heterostructure photoelectrocatalyst.

[0008] A method for preparing an In2S3 / In2MnS4 photoelectrocatalyst for the production of H2O2 or HClO includes the following steps:

[0009] 1) Dissolve In(NO3)3·xH2O and H2BDC in DMF solvent, stir, transfer to a round bottom flask for reaction, cool naturally to room temperature, centrifuge to collect the sample, wash several times with ethanol, and dry in an 80℃ oven for 12h to obtain MIL-68(In);

[0010] 2) Disperse the MIL-68(In) obtained in step 1) in an ethanol solution of CH4N2S, stir and transfer to a high-pressure reactor for reaction. After naturally cooling to room temperature, collect the sample by centrifugation, wash several times with deionized water and ethanol, and dry in an oven at 60℃ for 12h to obtain In2S3.

[0011] 3) Disperse the In2S3 obtained in step 2) in ethanol solvent, then add an ethanol solution of MnCl2·4H2O, stir until the ethanol evaporates, wash several times with deionized water and ethanol, and dry in an oven at 60℃ for 12h to obtain In2S3 / In2MnS4, that is, In2S3 / In2MnS4 S-type heterostructure photoelectrophotocatalyst.

[0012] Furthermore, in the above preparation method, in step 1), the mass ratio of In(NO3)3·xH2O to H2BDC is 1:1; the reaction conditions are reflux in an oil bath at 120°C for 0.5 h.

[0013] Furthermore, in the above preparation method, in step 2), the mass ratio of CH4N2S to MIL-68(In) is 3:1; the reaction conditions are 180℃ for 24h.

[0014] Furthermore, in the above preparation method, in step 3), the mass ratio of MnCl2·4H2O to In2S3 is 103:250; and the stirring temperature is 60℃.

[0015] Application of an In2S3 / In2MnS4 photoelectrocatalyst for the production of H2O2 or HClO in the photoelectrocatalytic production of H2O2.

[0016] Further, the above application is carried out as follows: An In2S3 / In2MnS4 S-type heterostructure photoelectrocatalyst is added to deionized water, ultrasonically dispersed, and coated onto PVDF-modified hydrophobic nickel foam as the working electrode. A platinum wire is used as the counter electrode, and a silver chloride electrode as the reference electrode. The system is placed in a quartz reaction vessel to form a three-electrode system. Under a bias voltage of -0.6V vs. Ag / AgCl and an ambient temperature of 25℃, a 300W xenon lamp is used to simulate sunlight irradiation. The xenon lamp λ≥420nm. The pH of a 0.1M Na2SO4 solution containing ethanol is adjusted to 3 using HClO4, and O2 is introduced. The reaction is carried out under photoelectric drive to catalyze the synthesis of H2O2.

[0017] Application of an In2S3 / In2MnS4 photoelectrocatalyst for the production of H2O2 or HClO in the photoelectrocatalytic production of HClO.

[0018] Further, the above application is carried out as follows: In2S3 / In2MnS4 S-type heterostructure photoelectrocatalyst is added to deionized water, ultrasonically dispersed, coated onto carbon paper as the working electrode, platinum wire as the counter electrode, silver chloride electrode as the reference electrode, and 35g / L NaCl solution as the electrolyte. The reaction is carried out in a quartz reaction vessel to form a three-electrode system. Under the conditions of 1.3V vs. Ag / AgCl bias voltage and ambient temperature of 25℃, a 300W xenon lamp is used to simulate sunlight irradiation. The xenon lamp λ≥420nm, and the reaction is carried out under photoelectric drive to catalyze the synthesis of HClO.

[0019] Furthermore, in the above-mentioned application in the photoelectrocatalytic production of H2O2 or HClO, the loading of the In2S3 / In2MnS4 S-type heterostructure photoelectrocatalyst is 3 mg.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. This invention synthesizes hollow hierarchical tubular In2S3 / In2MnS4 S-type heterojunction photocatalysts via ion exchange, which further improves photoresponse, suppresses recombination of photogenerated electron-hole pairs, increases electron-hole utilization, and enhances photocatalytic activity.

[0022] 2. Under visible light irradiation and a specific additional bias voltage, the yields of H2O2 and HClO produced by catalysis reached 2107.8 μmol / L and 28.5 mg / L, respectively, within 90 min, providing a green synthetic route and sustainable technology for the production of H2O2 and HClO.

[0023] 3. This invention is characterized by its simplicity, high efficiency, and low cost. The hollow hierarchical tubular In2S3 / In2MnS4 S-type heterojunction photoelectrocatalytic material prepared has the characteristics of narrow band gap, large specific surface area, good conductivity, and high catalytic activity. It also has good visible light absorption performance and good stability, high photogenerated electron-hole pair separation efficiency, fast interfacial charge transport efficiency, and high production yield of H2O2 and HClO. It can be applied to the photoelectrocatalytic production of H2O2 and HClO. Attached Figure Description

[0024] Figure 1 These are scanning electron microscope (SEM) images of MIL-68(In)(a), In2S3(b), In2S3 / In2MnS4(c), and In2MnS4(d).

[0025] Figure 2 These are the XRD diffraction patterns of In2S3, In2S3 / In2MnS4, and In2MnS4.

[0026] Figure 3 The transient photocurrent curves (a) and impedance curves (b) of In2S3, In2S3 / In2MnS4, and In2MnS4 are shown.

[0027] Figure 4 This is a comparison chart of the yield of H2O2 synthesized by photoelectrocatalysis of In2S3 / In2MnS4 / PVDF / NF under different gaseous environments.

[0028] Figure 5 This is a graph showing the change in H2O2 production by photoelectrochemical synthesis of In2S3 / In2MnS4 / PVDF / NF at different pH values.

[0029] Figure 6 This is a comparison chart of the yield of HClO synthesized by photoelectrocatalysis under different material loadings of In2S3 / In2MnS4 / CP.

[0030] Figure 7 This is a comparison chart of the yield of HClO synthesized by photoelectrocatalysis under different concentrations of NaCl solution using In2S3 / In2MnS4 / CP. Detailed Implementation

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

[0032] Example 1: Preparation of Hollow Hierarchical Tubular In2S3 / In2MnS4 S-type Heterostructure Photoelectrocatalyst (I) Preparation of MIL-68 (In)

[0033] Weigh 60 mg In(NO3)3·xH2O and 60 mg H2BDC respectively, dissolve them in 40 mL DMF, stir to form a clear solution, then transfer it to a round-bottom flask, reflux in an oil bath at 120 °C for 0.5 h, collect the product after natural cooling to room temperature, wash several times with ethanol, and dry at 80 °C for 12 h to obtain MIL-68(In).

[0034] (II) Preparation of hollow, graded tubular In2S3

[0035] Weigh 0.3 g of CH4N2S and dissolve it in 15 mL of ethanol. Add 0.1 g of MIL-68 (In) and continue stirring for 10 min. Then transfer the solution to a Teflon autoclave and heat it to 180 °C for 24 h. After naturally cooling to room temperature, collect the precipitate by centrifugation, wash it several times with deionized water and ethanol, and dry it in an oven at 60 °C for 12 h to obtain hollow fractional tubular In2S3.

[0036] (III) Preparation of hollow, graded tubular In2S3 / In2MnS4

[0037] Weigh 30 mg In2S3 and disperse it in 20 mL of ethanol. Weigh 12.36 mg MnCl2·4H2O and dissolve it in 10 mL of ethanol. Mix the two under stirring, and then continue stirring at 60 °C until the ethanol is completely evaporated. Wash several times with distilled water and ethanol, and dry in an oven at 60 °C for 12 h to obtain hollow hierarchical tubular In2S3 / In2MnS4.

[0038] (iv) Testing

[0039] 1. For example Figure 1 As shown, (a)-(c) represent the morphologies of MIL-68(In), In2S3, and In2S3 / In2MnS4 materials, respectively. It can be observed that MIL-68(In) has a smooth hexagonal prism structure, In2S3 exhibits a rather rough petal-like surface and hollow tubular structure, and In2S3 / In2MnS4 exhibits an even rougher petal-like surface and hollow tubular structure.

[0040] 2. For example Figure 2 As shown, the crystal structure of In2S3 / In2MnS4 was determined by XRD diffraction patterns. With the increase of Mn... 2+ The ion exchange shows that the (222) crystal plane at 28.8° corresponds to In2S3 (JCPDS NO.32-0456), and the diffraction peaks at 27.6°, 33.4° and 48° correspond very closely to the (311), (400) and (440) crystal planes of In2MnS4 (JCPDS No.31-0594).

[0041] 3. For example Figure 3 As shown in (a) the transient photocurrent curve, it can be seen that under illumination, the transient photocurrent increases rapidly. The transient photocurrent of In2S3 / In2MnS4 is larger than that of In2S3 and In2MnS4, indicating that the In2S3 / In2MnS4 heterojunction was successfully synthesized and has better photoelectric response. As shown in (b) the impedance curve, it can be seen that the arc radius of In2S3 / In2MnS4 is smaller than that of In2S3 and In2MnS4, indicating that the charge carriers are effectively transferred and separated.

[0042] Example 2: Photoelectrocatalytic production of H2O2

[0043] The method is as follows:

[0044] 1) Weigh 45 mg of PVDF and add it to 15 mL of ethanol / water mixture (V 乙醇 :V 水 =1:4), sonicate for 15 min, soak nickel foam (2cm×3cm) for 10 min, and calcine in a muffle furnace at 240℃ for 0.5 h; weigh 5mg In2S3 / In2MnS4 composite material, add to 1mL deionized water, sonicate for 20 min, drop the dispersion onto PVDF modified nickel foam with a pipette, and calcine in a muffle furnace at 120℃ for 0.5 h to obtain photocathode In2S3 / In2MnS4 / PVDF / NF.

[0045] 2) Using the photocathode obtained in step 1) as the working electrode, Pt as the counter electrode, and Ag / AgCl as the reference electrode, a three-electrode system was formed in a quartz reaction vessel. Under the conditions of -0.6V vs. Ag / AgCl bias voltage and ambient temperature of 25℃, a 300W xenon lamp was used to simulate sunlight irradiation. The xenon lamp λ≥420nm. The three-electrode system was inserted into a quartz reactor containing 20mL of 0.1mol / L Na2SO4 solution with ethanol. The pH of the solution was adjusted with 0.5mol / L HClO4. O2 was continuously introduced into the solution for 30min under dark conditions. During the photoelectric driven catalytic reaction, 0.5mL of solution was taken out every 30min, and the yield of H2O2 was detected by potassium titanium oxalate colorimetric method.

[0046] (I) The Influence of Different Gas Environments on H2O2 Formation

[0047] In a 20 mL solution of 0.1 mol / L Na₂SO₄ containing ethanol at pH 3, N₂, Air, and O₂ were introduced into the solution for 30 min under dark conditions. H₂O₂ was produced using an In₂S₃ / In₂MnS₄ / PVDF / NF photocathode. The results are as follows: Figure 4 As shown.

[0048] The yield of H2O2 is highest under O2 / visible light irradiation conditions; when air is introduced into the solution, the yield of H2O2 decreases due to the low oxygen content in the air; when N2 is introduced into the solution, the generation of H2O2 is almost completely suppressed, indicating that O2 is crucial for the photoelectrocatalytic production of H2O2.

[0049] (II) The effect of different pH values ​​on H2O2 formation

[0050] In 20 mL of 0.1 mol / L Na₂SO₄ solution containing ethanol, the pH values ​​were adjusted to 2, 3, and 5 using 0.5 mol / L HClO₄, respectively. O₂ was then introduced into the solution for 30 min under dark conditions. H₂O₂ was produced using an In₂S₃ / In₂MnS₄ / PVDF / NF photocathode. The results are as follows: Figure 5 As shown.

[0051] The yield of H2O2 reaches its maximum at pH=3, while the yield decreases at pH=5 or pH=2, indicating that the performance of photoelectrocatalytic production of H2O2 also depends on the pH of the solution.

[0052] Example 3: Photoelectrocatalytic production of HClO

[0053] The method is as follows:

[0054] 1) Weigh 3 mg of In2S3 / In2MnS4 composite material, add it to 0.4 mL of deionized water, sonicate for 20 min, use a pipette to drop the dispersion onto carbon paper (2 cm × 3 cm), and let it air dry to obtain the photoanode In2S3 / In2MnS4 / CP.

[0055] 2) Using the photoanode obtained in step 1) as the working electrode, Pt as the counter electrode, and Ag / AgCl as the reference electrode, a three-electrode system was formed in a quartz reaction vessel. Under the conditions of 1.3V vs. Ag / AgCl bias voltage and ambient temperature of 25℃, a 300W xenon lamp was used to simulate sunlight irradiation. The xenon lamp λ≥420nm. The three-electrode system was inserted into a quartz reactor containing 20mL of 35g / L NaCl solution. During the photoelectric driven catalytic reaction, 0.1mL of solution was taken out every 30min, and the yield of HClO was detected by DPD colorimetry.

[0056] (I) The effect of different material loading on HClO formation

[0057] In 20 mL of 35 g / L NaCl solution, HClO was produced using In2S3 / In2MnS4 / CP composite materials with loadings of 1 mg, 3 mg, and 5 mg of In2S3 / In2MnS4 / CP as photoanodes. The results were as follows: Figure 6 As shown.

[0058] The highest HClO yield was observed when the material loading was 3 mg, indicating that the material loading effectively improved the catalytic performance of the electrode. However, excessive catalyst loading could lead to an overly thick catalyst layer, which could cause material detachment. Therefore, the optimal loading was 3 mg.

[0059] (II) Effects of different concentrations of NaCl solution on the formation of HClO

[0060] In 20 mL of NaCl solutions with concentrations of 5 g / L, 15 g / L, 25 g / L, and 35 g / L, HClO was produced using In₂S₃ / In₂MnS₄ / CP with a material loading of 3 mg as the photoanode. The results are as follows: Figure 7 As shown.

[0061] The highest yield of HClO was observed when the concentration of the NaCl solution was 35 g / L. This shows that increasing the NaCl concentration effectively increased the yield of HClO. This is because the increased concentration of NaCl as an electrolyte enhances its conductivity, promotes electron transport, and facilitates the photoelectric reaction. Furthermore, the increased NaCl concentration allows more NaCl to participate as a reactant in the production of HClO. Therefore, 35 g / L was chosen as the optimal NaCl solution concentration.

Claims

1. Use of an In2S3 / In2MnS4 photoelectrocatalyst for the production of H2O2 or HCIO in the photoelectrocatalytic production of H2O2 or HCIO, characterized in that, The aforementioned In2S3 / In2MnS4 photoelectrocatalyst for producing H2O2 or HClO is prepared by synthesizing MIL-68(In) from In(NO3)3·xH2O and H2BDC via oil bath reflux. MIL-68(In) is then sulfided to In2S3 via a solvothermal method, and a portion of In2S3 is exchanged to In2MnS4 via an ion exchange method, thus obtaining the In2S3 / In2MnS4 S-type heterostructure photoelectrocatalyst. The solvothermal sulfidation of MIL-68(In) to In2S3 involves dispersing MIL-68(In) in an ethanol solution of CH4N2S at a mass ratio of 3:1, stirring, and then transferring the solution to a high-pressure reactor for reaction at 180°C for 24 hours. The ion exchange method for partially exchanging In2S3 to In2MnS4 involves dispersing In2S3 in an ethanol solvent, and then adding MnCl2·xH2O. An ethanol solution of 4H2O was prepared, with a mass ratio of MnCl2·4H2O and In2S3 of 103:250, and stirred until the ethanol evaporated.

2. The application according to claim 1, characterized in that, The preparation method of the In2S3 / In2MnS4 photoelectrocatalyst for producing H2O2 or HClO includes the following steps: 1) Dissolve In(NO3)3·xH2O and H2BDC in DMF solvent, stir, transfer to a round bottom flask for reaction, cool naturally to room temperature, centrifuge to collect the sample, wash several times with ethanol, and dry in an 80℃ oven for 12h to obtain MIL-68(In); 2) Disperse the MIL-68(In) obtained in step 1) in an ethanol solution of CH4N2S, stir and transfer to a high-pressure reactor for reaction. After naturally cooling to room temperature, collect the sample by centrifugation, wash several times with deionized water and ethanol, and dry in an oven at 60℃ for 12h to obtain In2S3. 3) Disperse the In2S3 obtained in step 2) in ethanol solvent, then add an ethanol solution of MnCl2·4H2O, stir until the ethanol evaporates, wash several times with deionized water and ethanol, and dry in an oven at 60℃ for 12h to obtain In2S3 / In2MnS4, that is, In2S3 / In2MnS4 S-type heterostructure photoelectrophotocatalyst.

3. The application according to claim 2, characterized in that, In step 1), the mass ratio of In(NO3)3·xH2O to H2BDC is 1:1; the reaction conditions are reflux in an oil bath at 120°C for 0.5 h.

4. The application according to claim 2, characterized in that, In step 3), the stirring temperature is 60°C.

5. The application according to claim 1, characterized in that, The application method of the In2S3 / In2MnS4 photoelectrocatalyst for producing H2O2 or HClO in the photoelectrocatalytic production of H2O2 is as follows: The In2S3 / In2MnS4 S-type heterostructure photoelectrocatalyst is added to deionized water, ultrasonically dispersed, and coated onto PVDF-modified hydrophobic nickel foam as the working electrode, with a platinum wire as the counter electrode and a silver chloride electrode as the reference electrode. The system is placed in a quartz reaction vessel to form a three-electrode system. Under the conditions of -0.6 V vs. Ag / AgCl bias voltage and an ambient temperature of 25℃, a 300 W xenon lamp is used to simulate sunlight irradiation. The xenon lamp λ≥420nm. The pH value of a 0.1 M Na2SO4 solution containing ethanol is adjusted to 3 using HClO4, and O2 is introduced. The reaction is carried out under photoelectric drive to catalyze the synthesis of H2O2.

6. The application according to claim 1, characterized in that, The application method of the In2S3 / In2MnS4 photoelectrocatalyst for the production of H2O2 or HClO in the photoelectrocatalytic production of HClO is as follows: The In2S3 / In2MnS4 S-type heterostructure photoelectrocatalyst is added to deionized water, ultrasonically dispersed, coated onto carbon paper as the working electrode, a platinum wire as the counter electrode, a silver chloride electrode as the reference electrode, and a 35 g / L NaCl solution as the electrolyte. The reaction is carried out in a quartz reaction vessel to form a three-electrode system. Under the conditions of 1.3 V vs. Ag / AgCl bias voltage and an ambient temperature of 25℃, a 300 W xenon lamp is used to simulate sunlight irradiation. The xenon lamp λ≥420nm, and the reaction is carried out under photoelectric drive to catalyze the synthesis of HClO.

7. The application according to claim 5 or 6, characterized in that, The loading amount of the In2S3 / In2MnS4 S-type heterostructure photoelectrophotocatalyst is 3 mg.

Images