An In2Se3@N,SC / Cd0.8Zn0.2S composite material for photocatalytic hydrogen peroxide production and its preparation method.

Abstract

The application discloses a kind of Z-type heterojunction photocatalytic materials (In2Se3@N,S-C / Cd 0.8 Zn 0.2 S) based on In2Se3 Construction and its application in photocatalytic synthesis hydrogen peroxide (H2O2) coupling benzyl alcohol oxidation, belong to the field of photocatalytic material.The material is prepared by three steps:1) In-MOF is synthesized by solvothermal method;2) In2Se3@N,S-C nanorod is prepared by selenizing In-MOF at high temperature;3) In2Se3@N,S-C nanorod is combined with Cd 0.8 Zn 0.2 S nanoparticle to form heterojunction by solvothermal method.This structure effectively promotes photoinduced carrier separation, while retaining strong redox ability.Experiments show that under LED blue light, the material reduces oxygen (O2) to generate H2O2, with a yield of 5.8 mmol·g ‑1 ·h ‑1 , and can selectively (99%) oxidize benzyl alcohol to benzaldehyde.The application has the advantages of simple process, low cost, environmental friendliness, etc., and provides a new way for green synthesis of H2O2.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor photocatalytic materials, specifically relating to a method for preparing a catalytic material for photocatalytic reduction of oxygen to prepare hydrogen peroxide and coupled oxidation of benzyl alcohol, and its application. Background Technology

[0002] Hydrogen peroxide (H2O2), as an environmentally friendly oxidant and a potential clean energy carrier, has significant application value in chemical synthesis, environmental remediation, medical disinfection, and new energy development. Currently, industrial-scale H2O2 production mainly relies on the anthraquinone process, which involves multi-step hydrogenation / oxidation cycles and precious metal catalysts, resulting in complex steps, high energy consumption, and organic solvent pollution. In contrast, solar-driven photocatalytic oxygen reduction synthesis technology, by simulating the natural photosynthetic pathway, can directly convert O2 and H2O into H2O2 at room temperature and pressure, offering advantages in both green economy and sustainability. Although various semiconductor photocatalysts (such as TiO2 and g-C3N4) have been developed for this system in recent years, their practical application is still limited by bottlenecks such as low photogenerated carrier separation efficiency and insufficient visible light utilization. Some systems also require sacrificial agents to maintain activity, leading to increased costs and the risk of secondary pollution. Therefore, developing novel photocatalytic materials with high efficiency, stability, and broad spectral response has become a key breakthrough direction for promoting the industrial application of this technology. Summary of the Invention

[0003] The purpose of this invention is to solve the technical problem of unsatisfactory yield when using In2Se3 alone for photocatalytic preparation of hydrogen peroxide, and to provide an In2Se3@N,SC / Cd catalyst for hydrogen peroxide production. 0.8 Zn 0.2 S photocatalyst and its preparation method.

[0004] The In2Se3@N,SC / Cd photocatalyst of this invention is used to prepare hydrogen peroxide and benzaldehyde. 0.8 Zn 0.2 The preparation method of S composite material is carried out according to the following steps:

[0005] 1. Dissolve indium salt, organic ligand, and 1,2-benzisothiazol-3-one in an organic solvent, then heat in a high-pressure reactor to 120–180°C. After cooling and washing several times, a white powder In-MOF is obtained.

[0006] 2. The obtained In-MOF and selenium powder are placed in a tube furnace and heated to 400-700℃. After cooling, the reddish-brown In2Se3@N,SC is collected.

[0007] 3. Dissolve cadmium salts, zinc salts, and sodium sulfide in an organic solvent, heat to 120–200°C, cool, centrifuge, and wash to obtain a yellow powder, Cd.0.8 Zn 0.2 S.

[0008] IV. In2Se3@N,SC and Cd 0.8 Zn 0.2 S was dispersed in an organic solvent, heated to 120–200 °C, cooled, and then centrifuged and washed to obtain In₂Se₃@N,SC / Cd. 0.8 Zn 0.2 S.

[0009] Step four involves In2Se3@N,SC and Cd 0.8 Zn 0.2 The mass ratio of S is 1:(1~20).

[0010] The In2Se3@N,SC / Cd photocatalyst of this invention is used to prepare hydrogen peroxide and benzaldehyde. 0.8 Zn 0.2 The application of the S composite material involves placing the catalyst in an oxygen-saturated aqueous solution containing benzyl alcohol and irradiating it under LED blue light to prepare H2O2 with a yield of 5.8 mmol·g-1·h-1, while the selectivity of benzyl alcohol to benzaldehyde is as high as 99%.

[0011] This invention develops a structural heterojunction of In2Se3@N,SC / Cd 0.8 Zn 0.2 The preparation method of the S-composite photocatalytic material includes three key steps: First, an In-MOF precursor is doped with N and S elements and then subjected to vacuum pyrolysis and selenization to form carbon-coated In2Se3 nanorods (In2Se3@N,SC); then, Cd is loaded onto the material surface using a solvothermal method. 0.8 Zn 0.2 S forms a tight heterogeneous interface. With a single Cd 0.8 Zn 0.2 Compared to S or In2Se3@N,SC, this heterojunction system exhibits a significantly improved yield in the photocatalytic oxygen reduction to H2O2 production process, and achieves a substrate conversion rate of nearly 99% in the selective oxidative coupling reaction of benzyl alcohol. Mechanistic studies show that the construction of the Z-type heterojunction not only promotes the spatial separation of photogenerated electron-hole pairs through band matching effects, but also drives the directional migration of electrons through the built-in electric field at the interface, suppressing recombination losses while retaining the strong reducing power of In2Se3 and the Cd... 0.8 Zn 0.2 Oxidation properties of sulfur. Attached Figure Description

[0012] Figure 1 This is the X-ray diffraction pattern of the In-MOF of this invention;

[0013] Figure 2 This is a scanning electron microscope image of the In-MOF of this invention;

[0014] Figure 3 This is the X-ray diffraction pattern of In2Se3@N,SC of the present invention;

[0015] Figure 4 This is a scanning electron microscope image of In2Se3@N,SC of the present invention;

[0016] Figure 5 For the present invention Cd 0.8 Zn 0.2 X-ray diffraction pattern of S;

[0017] Figure 6 For the present invention Cd 0.8 Zn 0.2 Scanning electron microscope image of S;

[0018] Figure 7 This invention relates to In2Se3@N,SC / Cd 0.8 Zn 0.2 X-ray diffraction pattern of S;

[0019] Figure 8 This invention relates to In2Se3@N,SC / Cd 0.8 Zn 0.2 Scanning electron microscope image of S;

[0020] Figure 9 This invention relates to In2Se3@N,SC / Cd 0.8 Zn 0.2 Element mapping graph of S;

[0021] Figure 10 For the present invention Cd 0.8 Zn 0.2 S, In2Se3@N,SC and In2Se3@N,SC / Cd 0.8 Zn 0.2 Results of S's photocatalytic hydrogen peroxide production effect;

[0022] Figure 11 For the present invention Cd 0.8 Zn 0.2 S, In2Se3@N,SC and In2Se3@N,SC / Cd 0.8 Zn 0.2 NMR results of photocatalytic oxidation of S to benzaldehyde; Detailed Implementation

[0023] To better understand the present invention, the following examples further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0024] Example 1

[0025] 40 mg In(NO3)3·xH2O, 60 mg terephthalic acid (C8H6O4), and 30 mg 1,2-benzisothiazol-3-one were weighed and dissolved in 20 ml of DMF. After ultrasonic dissolution, the solution was transferred to a high-pressure reactor and reacted at 160 °C for 10 h. After natural cooling to room temperature, the solution was washed several times by centrifugation with deionized water and ethanol, and then dried overnight at 60 °C in a vacuum drying oven to obtain In-MOF. Figure 1 The X-ray diffraction pattern confirms that the synthesized material is In-MOF, while from... Figure 2 It can be seen that In-MOF is a uniform hexagonal prism.

[0026] Example 2

[0027] Weigh 10 mg of In-MOF and 10 mg of selenium powder, place them in a tube furnace, heat to 650°C, maintain for 1 hour, cool to room temperature, and collect the powder to obtain In2Se3@N,SC. Figure 3 The X-ray diffraction pattern confirms that the synthesized compound is In2Se3. Figure 4 It can be seen that it still retains the shape of a hexagonal prism, but the surface has become rough.

[0028] Example 3

[0029] Weigh 33 mg ZnCl2, 50 mg CdCl2·2.5H2O and 12 mg Na2S·9H2O and disperse them in 50 ml ethylene glycol solution. Heat to 120 °C under reflux and maintain for 1 h. After naturally cooling to room temperature, wash several times with deionized water and ethanol by centrifugation, and dry overnight in a vacuum drying oven at 60 °C to obtain CdCl2. 0.8 Zn 0.2 S. Through Figure 5 The X-ray diffraction pattern can prove that the synthesized compound is Cd. 0.8 Zn 0.2 S, from Figure 6 It can be seen that Cd 0.8 Zn 0.2 S represents nanoparticles.

[0030] Example 4

[0031] Weigh out 50 mg of In2Se3@N,SC and 50 mg of Cd. 0.8 Zn 0.2 S was dispersed into 50 ml of ethylene glycol and heated to 200 °C in a high-pressure reactor for 1 hour. After natural cooling to room temperature, the mixture was washed several times by centrifugation with deionized water and ethanol, and then dried overnight at 60 °C in a vacuum drying oven to obtain In2Se3@N,SC / Cd. 0.8 Zn 0.2 S. Figure 7 For In2Se3@N,SC / Cd 0.8 Zn 0.2 The X-ray diffraction pattern of S confirms the presence of In2Se3 and Cd in the sample. 0.8 Zn 0.2 S. Figure 8 This is a scanning electron microscope image, and... Figure 4 Compared to surface loading, In2Se3@N,SC contains many small particles. Figure 9 The elemental mapping diagram proves the existence of elements In, Se, Cd, Zn, S, C, and N. Therefore, it can be proven that In₂Se₃@N,SC / Cd was synthesized. 0.8 Zn 0.2 S.

[0032] Application Example 1

[0033] This embodiment uses a 3W LED blue light source to emit 5mg of Cd. 0.8 Zn 0.2 S and 0.1 ml of benzyl alcohol were added to a reaction flask containing 10 ml of water. After purging with oxygen for 5 min, the reaction was started under light for 3 h.

[0034] In this embodiment, the catalyst was removed by centrifugation to obtain a clear solution, and the concentration of H2O2 in the solution was determined by the potassium titanium oxalate colorimetric method. However, it may not have been detected because the concentration of H2O2 was too low.

[0035] Application Example 2

[0036] In this embodiment, a 3W LED blue light source was used as the light source. 5mg In2Se3@N,SC and 0.1ml benzyl alcohol were added to a reaction flask containing 10ml of water. After purging with oxygen for 5min, the photo-reaction was started for 3h.

[0037] In this embodiment, after removing the catalyst by centrifugation, a clear solution was obtained. The concentration of H2O2 in the solution was determined by the potassium titanium oxalate colorimetric method, and the yield of H2O2 was 0.72 mmol·g. -1 ·h -1 .

[0038] Application Example 3

[0039] This embodiment uses a 3W LED blue light source to emit 5mg In2Se3@N,SC / Cd. 0.8 Zn 0.2 S and 0.1 ml of benzyl alcohol were added to a reaction flask containing 10 ml of water. After purging with oxygen for 5 min, the reaction was started under light for 3 h.

[0040] In this embodiment, after removing the catalyst by centrifugation, a clear solution was obtained. The concentration of H2O2 in the solution was determined by the potassium titanium oxalate colorimetric method, and the yield of H2O2 was 5.8 mmol·g. -1 ·h -1 .

[0041] like Figure 10 For Cd 0.8 Zn 0.2 S, In2Se3@N,SC and In2Se3@N,SC / Cd 0.8 Zn 0.2 The rate of H2O2 production of the photocatalysts prepared in S2-4, and Cd alone. 0.8 Zn 0.2 S has little or no activity in producing H2O2, while In2Se3@N, SC has a yield of 0.72 mmol·g. -1 ·h -1 The yield after combining the two to form a heterojunction was 5.8 mmol·g. -1 ·h -1 This resulted in a significant improvement, and examination of the liquid phase products revealed that the selectivity of benzaldehyde was over 99% (e.g. Figure 11 ).

[0042] The above embodiments are merely examples of specific implementations of the present invention. Although the descriptions are detailed and specific, they should not be considered as limiting the scope of patent protection. Any reasonable modifications, structural optimizations, and functionally equivalent substitutions made by those skilled in the art based on the core technical solutions of the present invention should be considered to fall within the scope of protection of the present invention.

Claims

1. An In2Se3@N,SC / Cd 0.8 Zn 0.2 The synthesis method of S composite material includes the following steps: (1). Indium salt, organic ligand compound and solvent are mixed, and then the solution is heated to 120-180℃ in a high pressure reactor and maintained for 4-6h. After cooling, centrifugation and washing, In-MOF is obtained. (2). The obtained In-MOF and selenium powder were placed in a tube furnace and heated to 400-700℃. After cooling, the reddish-brown In2Se3@N,SC was collected. (3) Dissolve cadmium salt, zinc salt and sodium sulfide in an organic solvent and heat to 120-200°C. After cooling, centrifuge and wash to obtain a yellow powder Cd. 0.8 Zn 0.2 S. (4). Mix In2Se3@N,SC and Cd 0.8 Zn 0.2 S was dispersed in an organic solvent, heated to 120–200 °C, cooled, and then centrifuged and washed to obtain In₂Se₃@N,SC / Cd. 0.8 Zn 0.2 S.

2. The method according to claim 1, characterized in that, The metal salt mentioned in the steps is selected from any one or more of the following: chloride salts, nitrate salts, or their hydrates.

3. The method according to claim 1, characterized in that, The organic ligands mentioned in the steps are selected from one or more of the following: terephthalic acid, 2-aminoterephthalic acid, or pyromellitic acid.

4. The method according to claim 1, characterized in that, The organic solvent used in the step is selected from one or more of the following: methanol, ethanol, N,N-dimethylformamide, or ethylene glycol.

5. The method according to claim 1, characterized in that, The calcination atmosphere in step (2) is selected from one or more of the following: air, nitrogen, vacuum or argon.

6. The method according to claim 1, characterized in that, The total amount of indium salt, organic ligand compound and solvent added in step (1) is 1-10 mmol / L.

7. The method according to claim 1, characterized in that, The mass ratio of In-MOF to selenium powder in step (2) is 1:1-10.

8. An In2Se3@N,SC / Cd compound prepared by the method according to any one of claims 1-7 0.8 Zn 0.2 S composite material.

9. The In2Se3@N,SC / Cd as described in claim 8 0.8 Zn 0.2 Application of S composite material as a photocatalyst in the catalytic synthesis of hydrogen peroxide and benzaldehyde from water and oxygen.

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