Preparation method and application of nitrogen-doped indium zinc sulfide hybrid material
Nitrogen-doped ZnIn2S4 catalysts address the electron-hole recombination and selectivity issues in ZnIn2S4 by optimizing band structure and charge separation, achieving high selectivity and efficiency in benzyl alcohol oxidation to benzaldehyde.
Patent Information
- Application Number
- CN202510521265.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-24
- Publication Date
- 2025-07-15
AI Technical Summary
The existing ZnIn2S4 photocatalytic materials have problems with high electron hole recombination rate and insufficient catalytic selectivity in the benzyl alcohol oxidation reaction, making it difficult to achieve high selective conversion of benzaldehyde.
By introducing nitrogen doping, the band structure and electron density distribution of ZnIn2S4 are regulated, the photogenerated charge separation efficiency and hole migration ability are improved, and nitrogen-doped ZnIn2S4 (N-ZIS) material is prepared.
The selective conversion efficiency of benzyl alcohol to benzaldehyde is significantly improved, the photocatalytic selective oxidation performance is improved, and an efficient visible photocatalytic oxidation reaction is achieved.
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Abstract
Description
Technical Field
[0001] Disclosed is a preparation method of a nitrogen-doped zinc indium sulfide hybrid material, which is applied to the photocatalytic oxidation of benzyl alcohol to selectively produce benzaldehyde, and belongs to the technical fields of nanomaterials and photocatalysis. Background Art
[0002] Photocatalytic selective oxidation is a green and environmentally friendly organic transformation method, which can convert simple organic molecules into high-value products under mild conditions and has broad application prospects in the fields of fine chemicals and green synthesis. In particular, the oxidation reaction of benzyl alcohol under photocatalytic conditions, as a typical model reaction, can not only efficiently generate important intermediates such as benzaldehyde, but also help to reveal the electron transfer mechanism of photocatalytic materials. Therefore, it is of great significance to develop a highly efficient, simple to synthesize, and selective photocatalytic material for the oxidation and transformation of benzyl alcohol. During the photocatalytic oxidation of benzyl alcohol, the reaction usually involves the generation, separation, migration of photo-generated electron-hole pairs and the synergistic effect of surface redox reactions. Since this reaction belongs to the "oxidation half-reaction" under mild conditions, there are usually problems such as insufficient hole oxidation ability, fast electron-hole recombination, and poor reaction selectivity, making it difficult to achieve high-selectivity regulation of products (such as benzaldehyde). Currently, a variety of strategies have been proposed to optimize photocatalytic performance, such as constructing heterostructures, noble metal modification, defect engineering, non-metal element doping, etc. Among them, non-metal doping has shown great potential in regulating the band structure of semiconductors and the dynamic behavior of photo-generated carriers due to its advantages of simple operation, high regulation accuracy, and low cost. ZnIn2S4 (ZIS) is a typical metal sulfide semiconductor with a layered structure and excellent visible light response ability, and has been widely studied in photocatalytic water splitting, degradation of organic pollutants, etc. However, its application in the oxidation reaction of benzyl alcohol still faces problems such as high electron-hole recombination rate and insufficient catalytic selectivity. Therefore, researchers have tried to improve its catalytic performance through atomic-level regulation means.
[0003] Therefore, based on the above research background, from the perspective of regulating the separation efficiency of photo-generated charges and improving the catalytic oxidation selectivity, the present invention constructs a nitrogen-doped ZnIn2S4 photocatalytic material (N-ZIS), and systematically compares its performance with that of the undoped material in the visible-light photocatalytic oxidation of benzyl alcohol. On the one hand, nitrogen doping can introduce intermediate energy levels, effectively regulate the band structure and electron density distribution of ZIS, and improve the visible light response ability and carrier migration rate; on the other hand, doping with nitrogen elements can improve the surface electronic state of the material, promote the efficient migration of holes and the oxidation reaction of benzyl alcohol molecules, thereby significantly improving the selective conversion efficiency of benzyl alcohol to benzaldehyde. This material provides a reference for the construction of a new non-noble metal visible-light photocatalytic oxidation system. Summary of the Invention
[0004] In this invention, N, N-dimethylformamide (DMF) is used as the nitrogen source, and a nitrogen-doped zinc indium sulfide (N-ZnIn2S4) hybrid material is synthesized in one step by the solvothermal method. The specific preparation process of the nitrogen-doped zinc indium sulfide hybrid material used in this invention includes the following steps: Dissolve 136.32 mg of ZnCl2 and 586.35 mg of InCl3•4H2O in an appropriate amount of ultrapure water, and stir until a homogeneous and transparent solution is formed. Add a certain amount of thioacetamide (CH3CSNH2) to the solution prepared above, and continue to stir until it is completely dissolved. On this basis, add a certain volume ratio of DMF to make the total volume of the solution 80 mL, and then ultrasonically disperse for 30 min. Transfer the obtained mixed solution to a stainless steel autoclave and place it in an oven for hydrothermal reaction. After the reaction is completed, cool it to room temperature, wash the obtained solid product thoroughly with ethanol and ultrapure water in turn, and finally dry it in a vacuum drying oven at 60 °C to obtain the nitrogen-doped zinc indium sulfide hybrid material.
[0005] The nitrogen-doped zinc indium sulfide photocatalytic material, its preparation method and application described in this invention are characterized in that: in the second step, the addition amount of the sulfur source CH3CSNH2 is 300.52 - 601.04 mg; in the second step, the volume ratio of DMF to water added is 1:7 - 7:1; in the third step, the optimized hydrothermal reaction temperature is 145 - 165 °C, and the hydrothermal reaction time is 12 - 16 h.
[0006] Without introducing a nitrogen source (DMF), a pure-phase zinc indium sulfide material is prepared by the same method as above.
[0007] The application method of the catalyst described in this invention in the photocatalytic oxidation of benzyl alcohol to benzaldehyde is as follows:
[0008] Add 50 mg of the photocatalyst to a mixed solution containing 2 mmol of benzyl alcohol and 20 mL of acetonitrile, and load it into a 100 mL sealed photoreactor. Before the reaction, first introduce oxygen and maintain the air pressure in the reactor at 1 bar. At the same time, under the condition of magnetic stirring, let it stand in the dark for 30 min to achieve the adsorption-desorption equilibrium between the reactants and the catalyst surface. Subsequently, turn on a 300W xenon lamp as the light source, and filter out the ultraviolet part through a 420 nm cut-off filter, and only retain the visible light band to continuously irradiate the reaction system. During the photocatalytic reaction process, samples are taken at regular intervals, and a high performance liquid chromatograph is used to quantitatively analyze benzyl alcohol and its product benzaldehyde in the reaction solution. The total reaction time is 4 h to evaluate the catalytic performance and product selectivity of the prepared catalytic material in the photocatalytic selective oxidation reaction. Description of the Drawings
[0009] Figure 1XRD patterns of pure-phase zinc indium sulfide in Example 1 and nitrogen-doped zinc indium sulfide material in Example 2 were obtained. It was found that doping with non-metallic nitrogen had no obvious effect on the crystal structure of ZnIn2S4.
[0010] Figure 2 a and Figure 2 b are SEM images of pure-phase ZnIn2S4 in Example 1 and nitrogen-doped ZnIn2S4 (N-ZnIn2S4) in Example 2, respectively. Both ZnIn2S4 and N-ZnIn2S4 exhibit a nano-flower sphere structure, indicating that nitrogen doping does not affect the morphology of ZnIn2S4.
[0011] Figure 3 a is the photocatalytic oxidation activity diagram of pure-phase ZnIn2S4 in Example 1 and N-ZnIn2S4 with different nitrogen doping ratios in Examples 2, 4, and 5 for benzyl alcohol, Figure 3 b is the reaction conditions for the photocatalytic oxidation of benzyl alcohol by N-ZnIn2S4. With the increase in the amount of nitrogen doping, the conversion rate of benzyl alcohol gradually increases ( Figure 3 a). A small amount of nitrogen doping can greatly improve the conversion efficiency of benzyl alcohol in the photocatalytic oxidation process. Among them, the N20-ZnIn2S4 sample has the highest conversion rate of benzyl alcohol. Compared with the pure-phase zinc indium sulfide, the selectivity for the product benzaldehyde of the nitrogen-doped samples also increases, reaching more than 85% ( Figure 3 a). At the same time, its reaction conditions were also verified. In the absence of a catalyst and light, no benzaldehyde was detected at all, indicating that the benzaldehyde generated in the system comes from the catalytic action of the catalyst under light ( Figure 3 b); when the reaction gas atmosphere becomes air and N2, the conversion rates of the reaction both decrease significantly, indicating that light and O2 are both indispensable in the photocatalytic selective oxidation of benzyl alcohol to produce benzaldehyde ( Figure 3 b).
[0012] Figure 4 Room temperature fluorescence spectra ( Figure 4 a) and photocurrent response spectra ( Figure 4 b) of pure-phase ZnIn2S4 in Example 1 and N-ZnIn2S4 with different nitrogen doping ratios in Examples 2, 4, and 5. From Figure 4It can be seen that the pure ZnIn2S4 sample exhibits obvious fluorescence emission peaks under the excitation light irradiation, indicating that there is strong radiative recombination of photo-generated electrons and holes in its bulk phase. In the N-ZnIn2S4 sample doped with nitrogen, the fluorescence intensity is significantly weakened, especially in the samples with moderate doping amounts, indicating that the doping of nitrogen effectively inhibits the recombination process of photo-generated carriers. This phenomenon may be attributed to the band structure modulation caused by nitrogen doping and the introduction of surface defect states, which helps to promote the separation and migration of carriers. Photocurrent tests were carried out on ZnIn2S4 and N-ZnIn2S4 ( Figure 4 b). After nitrogen doping, the photocurrent density under visible light irradiation is significantly higher than that of undoped ZnIn2S4, indicating that under the regulation of nitrogen doping, the material can generate more photo-generated carriers and effectively participate in the charge transfer process, thus improving its photocatalytic activity.
[0013] Figure 5 Solid UV-visible diffuse reflectance spectra of pure-phase ZnIn2S4 in Example 1 and N-ZnIn2S4 with different nitrogen doping ratios in Examples 2 and 5 ( Figure 5 a) and corresponding powder color comparison diagrams ( Figure 5 b). As can be seen from Figure 5 a, all samples show good light absorption ability in the visible light range, indicating their potential visible light response performance. Compared with undoped ZnIn2S4, the absorption edge band of the samples doped with nitrogen shows a blue shift, which may be due to the change of the band structure caused by the introduction of nitrogen element, especially the fine-tuning of the valence band position, thus changing its optical band gap. And due to the doping of nitrogen, the color of the samples also changes ( Figure 5 b).
[0014] Figure 6 High-resolution XPS spectrum of N 1s of N-ZnIn2S4 in Example 2. The XPS results prove the existence of nitrogen element in N-ZnIn2S4 and the successful doping introduction of nitrogen element.
[0015] The above experimental results prove that the nitrogen-doped zinc indium sulfide photocatalytic material prepared by the present invention exhibits excellent catalytic activity and product selectivity for the selective oxidation reaction of benzyl alcohol under visible light irradiation, and can efficiently and stably convert benzyl alcohol into benzaldehyde, showing good application prospects. Among them, the introduction of nitrogen element not only effectively regulates the band structure of the material, but also enhances the separation efficiency of photo-generated charges, thus significantly improving the photocatalytic selective oxidation performance.
[0016] Although the content of the present invention has been introduced in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. Detailed implementation mode
[0017] The present invention will be described in more detail through specific embodiments below, but the protection scope of the present invention is not limited to these embodiments.
[0018] Example 1
[0019] Synthesis of pure-phase indium zinc sulfide 1:
[0020] Dissolve 136.32 mg of ZnCl2 and 586.35 mg of InCl3•4H2O in 80 mL of ultrapure water, and stir until a homogeneous and transparent solution is formed. Add 300.52 mg of CH3CSNH2 to the above-prepared solution, continue to stir until it is completely dissolved, and then ultrasonically disperse for 30 min. Transfer the obtained mixed solution to a stainless-steel autoclave and place it in an oven for hydrothermal reaction at 160 °C for 12 h. After the reaction is completed, cool it to room temperature, wash the obtained solid product thoroughly with ethanol and ultrapure water in sequence, and finally dry it in a vacuum drying oven at 60 °C to obtain pure-phase indium zinc sulfide (ZnIn2S4).
[0021] Example 2
[0022] Synthesis of nitrogen-doped indium zinc sulfide hybrid material 2:
[0023] Dissolve 136.32 mg of ZnCl2 and 586.35 mg of InCl3•4H2O in 70 mL of ultrapure water, and stir until a homogeneous and transparent solution is formed. Add 300.52 mg of CH3CSNH2 to the above-prepared solution, continue to stir until it is completely dissolved, then add 10 mL of DMF, and then ultrasonically disperse for 30 min. Transfer the obtained mixed solution to a stainless-steel autoclave and place it in an oven for hydrothermal reaction at 160 °C for 12 h. After the reaction is completed, cool it to room temperature, wash the obtained solid product thoroughly with ethanol and ultrapure water in sequence, and finally dry it in a vacuum drying oven at 60 °C to obtain the nitrogen-doped indium zinc sulfide hybrid material (N10-ZnIn2S4).
[0024] Example 3
[0025] Synthesis of nitrogen-doped indium zinc sulfide hybrid material 3:
[0026] 136.32 mg of ZnCl2 and 586.35 mg of InCl3•4H2O were dissolved in 70 mL of ultrapure water and stirred until a homogeneous and transparent solution was formed. 601.04 mg of CH3CSNH2 was added to the solution prepared above. After continuous stirring to completely dissolve it, 10 mL of DMF was added, and then ultrasonic dispersion was carried out for 30 min. The obtained mixed solution was transferred to a stainless-steel autoclave and placed in an oven at 160 °C for hydrothermal reaction for 12 h. After the reaction was completed, it was cooled to room temperature. The obtained solid product was washed thoroughly with ethanol and ultrapure water in turn, and finally dried in a vacuum drying oven at 60 °C to obtain a nitrogen-doped indium zinc sulfide hybrid material (N10-ZnIn2S4).
[0027] Example 4
[0028] Synthesis of nitrogen-doped indium zinc sulfide hybrid material 4:
[0029] 136.32 mg of ZnCl2 and 586.35 mg of InCl3•4H2O were dissolved in 60 mL of ultrapure water and stirred until a homogeneous and transparent solution was formed. 300.52 mg of CH3CSNH2 was added to the solution prepared above. After continuous stirring to completely dissolve it, 20 mL of DMF was added, and then ultrasonic dispersion was carried out for 30 min. The obtained mixed solution was transferred to a stainless-steel autoclave and placed in an oven at 160 °C for hydrothermal reaction for 12 h. After the reaction was completed, it was cooled to room temperature. The obtained solid product was washed thoroughly with ethanol and ultrapure water in turn, and finally dried in a vacuum drying oven at 60 °C to obtain a nitrogen-doped indium zinc sulfide hybrid material (N20-ZnIn2S4).
[0030] Example 5
[0031] Synthesis of nitrogen-doped indium zinc sulfide hybrid material 5:
[0032] 136.32 mg of ZnCl2 and 586.35 mg of InCl3•4H2O were dissolved in 50 mL of ultrapure water and stirred until a homogeneous and transparent solution was formed. 300.52 mg of CH3CSNH2 was added to the solution prepared above. After continuous stirring to completely dissolve it, 30 mL of DMF was added, and then ultrasonic dispersion was carried out for 30 min. The obtained mixed solution was transferred to a stainless-steel autoclave and placed in an oven at 160 °C for hydrothermal reaction for 12 h. After the reaction was completed, it was cooled to room temperature. The obtained solid product was washed thoroughly with ethanol and ultrapure water in turn, and finally dried in a vacuum drying oven at 60 °C to obtain a nitrogen-doped indium zinc sulfide hybrid material (N30-ZnIn2S4).
[0033] Example 6
[0034] Synthesis of nitrogen-doped zinc indium sulfide hybrid material 6:
[0035] Dissolve 136.32 mg of ZnCl2 and 586.35 mg of InCl3•4H2O in 60 mL of ultrapure water, and stir until a homogeneous and transparent solution is formed. Add 300.52 mg of CH3CSNH2 to the above-prepared solution, continue to stir until it is completely dissolved, then add 20 mL of DMF, and subsequently ultrasonically disperse for 30 min. Transfer the obtained mixed solution to a stainless-steel autoclave and place it in an oven for hydrothermal reaction at 145 °C for 16 h. After the reaction is completed, cool it to room temperature, wash the obtained solid product thoroughly with ethanol and ultrapure water in sequence, and finally dry it in a vacuum drying oven at 60 °C to obtain the nitrogen-doped zinc indium sulfide hybrid material (N20-ZnIn2S4).
Claims
1. A preparation method and application of a nitrogen-doped indium zinc sulfide photocatalytic material, characterized in that, The nitrogen-doped zinc indium sulfide material uses ZnCl2, InCl3•4H2O, and CH3CSNH2 as the precursors of zinc source, indium source, and sulfur source respectively. After being dissolved in water, a certain volume of DMF is added as the nitrogen source, and then it is transferred to a stainless-steel autoclave. The nitrogen-doped zinc indium sulfide is prepared by one-step hydrothermal method. This material is used for the photocatalytic selective oxidation of benzyl alcohol to benzaldehyde. The specific preparation process includes the following steps: (1) Dissolve 136.32 mg of ZnCl2 and 586.35 mg of InCl3.•4H2O in an appropriate amount of ultrapure water, and stir until a homogeneous and transparent solution is formed; (2) Add a certain amount of thioacetamide (CH3CSNH2) to the solution prepared above, continue to stir until it is completely dissolved, and then add a certain volume ratio of DMF to make the total volume of the solution 80 mL. Subsequently, ultrasonically disperse for 30 min; (3) Transfer the obtained mixed solution to a stainless-steel high-pressure reaction kettle and place it in an oven for hydrothermal reaction; after the reaction is completed, cool to room temperature. Wash the obtained solid product thoroughly with ethanol and ultrapure water in sequence, and finally dry it in a vacuum drying oven at 60 °C to obtain the nitrogen-doped zinc indium sulfide hybrid material (N-ZnIn2S4); The application method of the catalyst described in the present invention for the photocatalytic oxidation of benzyl alcohol to benzaldehyde is as follows: Add 50 mg of the photocatalyst to a mixed solution containing 2 mmol of benzyl alcohol and 20 mL of solvent, and load it into a 100 mL closed photoreactor; before the reaction, first introduce oxygen and maintain the air pressure in the reactor at 1 bar. At the same time, statically place it in the dark for 30 min under magnetic stirring conditions to achieve the adsorption-desorption equilibrium between the reactants and the catalyst surface; subsequently, turn on a 300 W xenon lamp as the light source and filter out the ultraviolet part through a 420 nm cut-off filter; during the photocatalytic reaction process, sample at regular intervals, and use a high-performance liquid chromatograph to quantitatively analyze benzyl alcohol and its product benzaldehyde in the reaction solution; the total reaction time is 4 hours to evaluate the catalytic performance and product selectivity of the prepared catalytic material in the photocatalytic selective oxidation reaction.
2. The preparation method and application of the nitrogen-doped indium zinc sulfide photocatalytic material according to claim 1, characterized in that: In step (2), the addition amount of the sulfur source CH3CSNH2 is 300.52~601.04 mg.
3. The preparation method and application of the nitrogen-doped indium zinc sulfide photocatalytic material according to claim 1, characterized in that: In step (2), the volume ratio of DMF to water added is 1:7~7:
1.
4. The preparation method and application of the nitrogen-doped indium zinc sulfide photocatalytic material according to claim 1, characterized in that: In step (3), the optimized hydrothermal reaction temperature is 145~165 °C, and the hydrothermal reaction time is 12~16 h.
5. The preparation method and application of the nitrogen-doped indium zinc sulfide photocatalytic material according to claim 1, characterized in that: The solid-liquid phase system is used for the photocatalytic oxidation of benzyl alcohol by this material, the solvent used is acetonitrile, and oxygen is used as the oxidant.