An improved method for preparing two-dimensional few-layer photocatalyst Zn2In2S5

Abstract

This invention discloses an improved method for preparing the two-dimensional few-layer photocatalyst Zn₂In₂S₅. The method includes: preparing a Zn₂In₂S₅ precursor using an oil bath synthesis method at a constant temperature of 90°C; naturally cooling to room temperature and then sonicating for 1 hour; subsequently washing alternately with deionized water and anhydrous ethanol; and vacuum drying to obtain the Zn₂In₂S₅ photocatalyst. The two-dimensional few-layer photocatalyst synthesized by this improved method is Zn₂In₂S₅-3. This Zn₂In₂S₅ photocatalyst can effectively catalyze the dehydrogenation of benzyl alcohol to benzaldehyde, achieving a highly efficient and green catalytic organic synthesis reaction, exhibiting good photocatalytic effect and stable photocatalytic properties.

Description

Technical Field

[0001] This invention belongs to the field of organic chemistry, specifically relating to an improved method for preparing a two-dimensional few-layer photocatalyst Zn2In2S5 and its application in the visible light photocatalytic dehydrogenation of benzyl alcohol to benzaldehyde. Background Technology

[0002] With the depletion of fossil fuels, there is an urgent need to develop more alternatives to meet current demands. Benzaldehyde, as a precursor to value-added chemicals, is widely used in the confectionery flavoring and pharmaceutical industries. The selective conversion of benzyl alcohol is an efficient route to obtain benzaldehyde. However, traditional strategies for converting benzyl alcohol often require toxic oxidants, such as environmentally harmful chromium (VI) or manganese (VI). In this context, photocatalytic alcohol oxidation is attracting increasing attention due to its environmental friendliness and low energy consumption. Among various photocatalytic alcohol conversion studies, O2-mediated photocatalytic alcohol oxidation, where O2 acts as an electron acceptor to promote alcohol conversion, is the most studied. In contrast, using hydrogen protons instead of oxygen in photo-oxidation-reduction reactions is an ideal approach that can both effectively utilize electron and hole energy and obtain green fuels. Therefore, under anaerobic conditions, photocatalytic oxidation coupled with hydrogen evolution is a promising scheme that can fully utilize photogenerated electrons and holes to obtain useful chemicals.

[0003] Currently, two-dimensional semiconductors with layered structures, unique electronic properties, and tunable band arrangements are considered candidate materials for photocatalytic reactions. The two-dimensional structure not only provides a large specific surface area and more active sites, but also exhibits rapid in-plane photoexcited carrier transfer due to short transport distances, thereby accelerating the photocatalytic oxidation rate of benzyl alcohol. Among these two-dimensional semiconductor materials, the bimetallic sulfur compound Zn... m In2S 3+m (m=1~3) is considered one of the most promising photocatalysts due to its atomic layer structure and suitable band gap structure, and has been extensively studied in the field of photocatalysis.

[0004] CN116651466A discloses Zn m In2S (m+3)As a ternary sulfur compound, Zn₂In₂S₅ exhibits a typical layered hexagonal structure. Zn₂In₂S₅ demonstrates high photocatalytic hydrogen production and degradation activity under visible light irradiation, along with excellent chemical stability. However, like most single catalysts, pure Zn₂In₂S₅ is subject to rapid recombination of photogenerated electron and hole pairs, resulting in low photocatalytic activity, necessitating further improvements in catalyst performance. CN116651466A and CN116060078B disclose a method for preparing Zn₂In₂S₅, in which 2 mmol of ZnSO₄·7H₂O, 2 mmol of InCl₃·xH₂O, and 10 mmol of thioacetamide are dissolved in a mixed solution of 30 mL of deionized water and 20 mL of glycerol. After stirring continuously for 1 h, the solution is transferred to a 100 mL polytetrafluoroethylene high-pressure reactor and reacted at 160 °C for 12 h. After cooling to room temperature, the yellow precipitate was washed three times each with deionized water and ethanol by centrifugation, and then dried in a vacuum oven at 60°C for 6 hours to obtain Zn₂In₂S₅. The peak shape and position of the XRD pattern of Zn₂In₂S₅ obtained by this method were completely consistent with those of the hexagonal Zn₂In₂S₅ reported in the literature. The prepared hexagonal Zn₂In₂S₅ was used for the degradation of tetracycline.

[0005] CN114950482B discloses a method for preparing Zn₂In₂S₅, which is prepared by reacting Zn(NO₃)₂·6H₂O, InCl₂, and thioacetamide, or by reacting Zn(C₂H₂O₂)₂·6H₂O, In(NO₃)₂, and thioacetamide in a mixed solution of ethanol and water at a high temperature of 170°C. The morphology is flower-like spheres assembled from ultrathin nanosheets, with a diameter of 3 μm to 5 μm. The yield of hydrogen and benzaldehyde (BAD) of the prepared Zn₂In₂S₅ under catalytic conditions is 9.41 mmol·g⁻¹. -1 ·h -1 and 12.17 mmol·g -1 ·h -1 .

[0006] Reference 1, Zhang H, Xie S, Hu J, et al. C–H activations of methanol and ethanol and C–C couplings into diols by zinc–indium–sulfide under visible light[J]. Chemical Communications, 2020, 56(12):1776-1779. The Electronic Supplementary Information discloses a method for preparing Zn2In2S5. This method involves dissolving 2.0 mmol InCl3·4H2O, Zn(CH3COO)2·2H2O, and (m+3) mmol thioacetamide in 160 mL of deionized (DI) water. The mixture is heated to 90 °C and vigorously stirred for 5 h at the same temperature. Afterward, the solution is allowed to cool naturally to room temperature. The suspension is continuously sonicated for 1 h. The precipitate is then collected by centrifugation, washed with deionized water and anhydrous ethanol, and dried overnight under vacuum at 60 °C. However, the Zn2In2S5 photocatalyst prepared by this method has low catalytic activity for the production of benzaldehyde from benzyl alcohol. The Zn2In2S5 photocatalyst obtained by this method is referred to as Zn2In2S5-1 in the following experiments.

[0007] The Zn₂In₂S₅ prepared by the above-mentioned prior art has a hexagonal crystal structure and a spherical structure. The inventors provide a two-dimensional few-layer Zn₂In₂S₅ photocatalyst. Summary of the Invention

[0008] The purpose of this invention is to provide an improved method for producing a two-dimensional few-layer photocatalyst Zn2In2S5, and the application of the Zn2In2S5 (labeled as Zn2In2S5-3 in the following experiments) obtained by this method in the catalytic production of benzaldehyde from benzyl alcohol under visible light.

[0009] To distinguish the two-dimensional few-layer photocatalyst Zn2In2S5 prepared by the method of this invention from the Zn2In2S5 catalyst of the prior art, and for the convenience of experiments in the following examples, it is labeled as Zn2In2S5-3 or Zn2In2S5-4. The prior art Zn2In2S5 disclosed in Document 1 is labeled as Zn2In2S5-1.

[0010] To achieve the objectives of this invention, the following implementation technical solutions are provided.

[0011] In one embodiment, an improved method for preparing the two-dimensional few-layer photocatalyst Zn₂In₂S₅ according to the present invention includes the following steps:

[0012] 1) Dissolve ZnAc2, InCl3 and thioacetamide in deionized water and stir the reaction at 80-100℃;

[0013] 2) After the reaction is complete, allow it to cool naturally to room temperature, then sonicate for 0.5-2 hours;

[0014] 3) After ultrasonication, the sample is washed and vacuum dried to obtain the two-dimensional few-layer photocatalyst Zn2In2S5 (such as Zn2In2S5-3 or Zn2In2S5-4).

[0015] The molar mass-volume ratio of ZnAc2 to deionized water is 1 mmol: (20-50) ml.

[0016] Preferably, in the improved method of the present invention described above, in step 1), the molar ratio of ZnAc2, InCl3 and thioacetamide is 2:2:5.

[0017] More preferably, InCl3 is InCl3·4H2O, and the molar mass-volume ratio of ZnAc2 to deionized water is 1 mmol: 40 ml.

[0018] Preferably, in the improved method of the present invention described above, in step 1), the stirring reaction is carried out at a constant rotation speed.

[0019] Preferably, in the improved method of the present invention described above, the reaction is carried out in a constant temperature oil bath at an oil bath temperature of 90°C for a reaction time of 5 hours.

[0020] Preferably, in the improved method of the present invention described above, in step 2), the ultrasound is performed at a frequency of 24 kHz for 1 hour.

[0021] Preferably, in the improved method of the present invention described above, in step 3), the washing involves alternating washing with deionized water and anhydrous ethanol three times.

[0022] Preferably, in the improved method of the present invention described above, in step 3), the drying temperature is 60°C.

[0023] Preferably, in the improved method of the present invention described above, the two-dimensional few-layer refers to a composition of 1-3 layers (see the above-mentioned document 1). Figure 1 (a)lew-layer).

[0024] Preferably, in the improved method of the present invention described above, the two-dimensional few-layer catalyst is Zn2In2S5-3 or Zn2In2S5-4, more preferably Zn2In2S5-3.

[0025] In another embodiment, the present invention also provides the use of Zn2In2S5 prepared by the improved method of the present invention described above for the catalytic dehydrogenation of benzyl alcohol, p-chlorobenzyl alcohol or p-fluorobenzyl alcohol to produce benzaldehyde, p-chlorobenzaldehyde or p-fluorobenzaldehyde.

[0026] Preferably, in the intended use, the reaction of benzyl alcohol, p-chlorobenzyl alcohol, or p-fluorobenzyl alcohol to produce benzaldehyde, p-chlorobenzaldehyde, or p-fluorobenzaldehyde by catalytic oxidation (dehydrogenation) is carried out in the solvent trifluorotoluene.

[0027] In one specific embodiment, an improved method for a two-dimensional few-layer photocatalyst Zn2In2S5 according to the present invention includes the following steps:

[0028] 1) Dissolve ZnAc2, InCl3·4H2O and thioacetamide (TAA) in 80 mL and 40 mL of deionized water respectively in a molar ratio of 2:2:5 to obtain a mixed solution. Place the solution in a 90℃ constant temperature oil bath and stir for 5 h.

[0029] 2) After the reaction is complete, allow it to cool naturally to room temperature, then sonicate for 1 hour;

[0030] 3) After ultrasonication, the samples were washed three times alternately with deionized water and anhydrous ethanol, and then vacuum dried to obtain two-dimensional few-layer photocatalysts Zn2In2S5-3 and Zn2In2S5-4.

[0031] Preferably, in the improved method of the present invention described above, in step 1), the molar mass-volume ratio of ZnAc2 to deionized water is 1 mmol: 40 ml; in step 2), the stirring is performed by stirring with a stir bar at a constant rotation speed; in step 3), the ultrasonication is performed at a frequency of 24 kHz for 1 hour; in step 3), the washing and drying are performed at a drying temperature of 60°C and under vacuum for 4 hours.

[0032] An improved method for preparing two-dimensional few-layer photocatalyst Zn₂In₂S₅ according to the present invention comprises the following steps:

[0033] (1) Dissolve ZnAc2, InCl3·4H2O and thioacetamide (TAA) in 80 mL of deionized water at a certain molar ratio of 2:2:5, wherein the molar mass-volume ratio of ZnAc2 to deionized water is 1 mmol: 40 mL.

[0034] (2) Place the volumetric flask containing the mixed solution in a 90℃ constant temperature oil bath and stir for 5 hours.

[0035] (3) After the reaction was completed, a yellow suspension was obtained, which was naturally cooled to room temperature and then sonicated for 1 hour.

[0036] (4) After ultrasonication, the sample was washed three times each with deionized water and anhydrous ethanol, and then dried under vacuum at 60°C for 4 hours to obtain the two-dimensional few-layer photocatalyst Zn2In2S5-3 (i.e., Zn2In2S5 prepared by the method of this invention).

[0037] The beneficial effects of the present invention: The preparation method of the present invention is an improvement on the preparation method of Reference 1, mainly by improving the amount of deionized water as the reaction solvent. Surprisingly, the Zn2In2S5 (i.e., Zn2In2S5-3) prepared by the improved method has significantly improved catalytic activity for benzyl alcohol dehydrogenation compared with Zn2In2S5 (i.e., Zn2In2S5-1) prepared by Reference 1.

[0038] Under visible light, the Zn₂In₂S₅ (i.e., Zn₂In₂S₅-3) prepared by the method of this invention exhibits excellent catalytic efficiency for the dehydrogenation of benzyl alcohol to benzaldehyde, superior to Zn₂In₂S₅ (i.e., Zn₂In₂S₅-1) prepared in Reference 1. The conversion rate of benzyl alcohol reaches over 99% within 3 hours, while the selectivity for benzaldehyde approaches 100%. Photocatalytic mechanism analysis shows that under N₂ conditions, benzyl alcohol is completely oxidized to benzaldehyde via photogenerated holes. This also indicates that Zn₂In₂S₅-3 has high photogenerated hole utilization and photogenerated carrier separation efficiency. This catalyst can efficiently catalyze the dehydrogenation of benzyl alcohol to benzaldehyde, is recyclable, and exhibits stable catalytic characteristics. Attached Figure Description

[0039] Figure 1 Characterization images of the two-dimensional few-layer Zn2In2S5 prepared in Example 1, where (a) is a scanning electron microscope (SEM) image of Zn2In2S5-3 and (b) is a field emission transmission electron microscope (TEM) image of Zn2In2S5-3.

[0040] Figure 2 Characterization diagrams of two-dimensional few-layer Zn2In2S5-3 prepared in Example 1 and Zn2In2S5-1 prepared by the method in Reference 1 are shown, wherein (a) is the Mott-Schottky test pattern of Zn2In2S5-3 and (b) are the UV-Vis diffuse reflectance absorption spectra of Zn2In2S5-1 and Zn2In2S5-3.

[0041] Figure 3 The BET test pattern of the two-dimensional few-layer Zn2In2S5-3 prepared in Example 1;

[0042] Figure 4 The experimental results of photocatalytic oxidation of benzyl alcohol in BTF solvent are shown in Examples 1 and 2 for the two-dimensional few-layer photocatalyst Zn2In2S5 and Zn2In2S5-1 from Reference 1.

[0043] Figure 5 The graph shows the photocatalytic activity (BAD conversion rate) of the two-dimensional few-layer photocatalyst Zn2In2S5-3 prepared in Example 1 in different solvents for benzyl alcohol oxidation.

[0044] Figure 6 XRD comparison images of the two-dimensional few-layer photocatalyst Zn2In2S5-3 prepared in Example 1 before and after catalytic reaction;

[0045] Figure 7 The image shows a comparison of the infrared spectra of the two-dimensional few-layer photocatalyst Zn2In2S5-3 prepared in Example 1 before and after the catalytic reaction. Detailed Implementation

[0046] The following examples are typical and are used to help understand and further illustrate the essence of the present invention, but are not intended to limit the scope of the present invention.

[0047] Example 1: Preparation of Zn2In2S5-3

[0048] The preparation process is as follows:

[0049] 1) Add 80 mL of deionized water to the reaction flask, and weigh out 2 mmol ZnAc2, 2 mmol InCl3·4H2O and 5 mmol thioacetamide (TAA) respectively. Add them to the reaction flask separately, stir to dissolve, and obtain a mixed solution.

[0050] 2) Place the reaction flask containing the mixed solution in a 90℃ constant temperature oil bath and stir constantly for 5 hours;

[0051] 3) After the reaction is complete, a yellow suspension is obtained. It is then allowed to cool naturally to room temperature and subsequently sonicated for 1 hour.

[0052] 4) After ultrasonication, the sample was washed three times each with deionized water and anhydrous ethanol, and then dried under vacuum at 60°C for 4 hours to obtain the two-dimensional few-layer photocatalyst Zn2In2S5-3.

[0053] The prepared Zn2In2S5-3 was tested by scanning electron microscopy and field emission transmission electron microscopy.

[0054] A small sample of the prepared product Zn2In2S5-3 was thoroughly ground in an agate mortar. The sample was then characterized for material morphology using environmental scanning electron microscopy (SEM, Thermo Fisher Scientific, Quattro S) and field emission electron microscopy (TEM, Thermo Fisher Scientific, Talos F200S). The SEM test results are shown below. Figure 1 (a) TEM test results are as follows Figure 1As shown in (b), the TEM image reveals that Zn2In2S5-3 is a two-dimensional layered structure.

[0055] FT-IR testing: Using the KBr pelleting method, 1 mg of the synthesized sample was added to 200 mg of KBr, mixed and ground evenly, and then pressed at 15 MPa for 30 seconds to form a disc with a diameter of 13 mm. Infrared reflectance data of the sample were collected on a Nicolet 360 spectrometer. The results are shown below. Figure 2 As shown, the resolution is 2cm. -1 The scanning range is 500–4000 cm. -1 . Figure 1 (b) indicates that all the major characteristic peaks of Zn2In2S5-3 were observed, which also indicates that the obtained sample is a pure phase.

[0056] The prepared Zn2In2S5-3 was subjected to Mott-Schottky testing:

[0057] 10 mg of the synthesized sample was added to a mixed solution containing 230 μL of deionized water, 250 μL of anhydrous ethanol, and 20 μL of Nafion solution to prepare a slurry. 10 μL of the slurry was then coated onto an ITO conductive glass plate (10 mm × 10 mm × 1 mm) to form a slide. Testing was performed using a DH7006 electrochemical workstation, and the results are as follows: Figure 2 As shown in (a), the flat band potential E of the catalyst fb For -0.69V vsSCE (-0.45V vs RHE), use formula E CB =E fb -0.1, the conduction band (CB) of the catalyst was calculated to be -0.55V vs RHE.

[0058] UV-Vis diffuse reflectance test of the prepared Zn2In2S5:

[0059] Take the prepared Zn2In2S5 and put it into a 1cm solution. 2 The disk was tested using a solid-state UV-Vis-NIR spectrometer (UV-2700i). The results are as follows: Figure 2 As shown in (b), the results indicate that the prepared two-dimensional few-layer material Zn2In2S5 absorbs visible light. Using the formula 1240 / λ, the band gaps of Zn2In2S5-1 and Zn2In2S5-3 are 2.75V and 2.66V, respectively. Subtracting the conduction band from the band gap yields the valence band (VB) of Zn2In2S5-3 as 2.11V vs RHE.

[0060] The prepared Zn2In2S5-3 was subjected to a BET test:

[0061] The specific surface area (BET) of the catalyst Zn₂In₂S₅ was determined using a fully automated multi-station specific surface area and pore size analyzer (MicrotracBEL, Japan). 500 mg of Zn₂In₂S₅ sample was placed into a sample tube. The sample tube was then installed in the degassing station, ensuring the sample tube was aligned with the port and the screws were tightened to ensure a secure seal. The heating element was then placed over the sample tube, and the file information and degassing temperature parameters were set. The vacuum pump was turned on to begin heating and vacuum degassing of the sample to remove adsorbed gases from the material surface. After degassing, the heating power was turned off, and the sample was allowed to cool to room temperature before being backfilled with nitrogen. The gross weight of the sample was then measured. The same sample tube, stopper, and filling rod were used for the following procedures. The sample weight was obtained by subtraction. The weighed sample tube was then placed in the analysis station, the test parameters were set, and the adsorption and desorption tests were initiated. After the test, the sample was removed from the sample tube. The sample tube was washed, dried, and stored for later use. The test results are shown in [link to data]. Figure 3 .

[0062] Example 2: Preparation of Zn2In2S5-4

[0063] The two-dimensional few-layer photocatalyst Zn₂In₂S₅-4 was prepared by referring to the method of the example, except that the amount of water in Example 1 was replaced with 40 ml.

[0064] Preparation of Comparative Example 1 Zn2In2S5-1

[0065] The photocatalyst Zn₂In₂S₅₁ was prepared according to the method described in Reference 1 above, using 160 ml of water.

[0066] Preparation of Comparative Example 2Zn2In2S5-2

[0067] The photocatalyst Zn₂In₂S₅₂ was prepared according to the method in Example 1, except that the amount of water in Example 1 was replaced with 120 ml.

[0068] Example 3: Application Effect Test

[0069] 1. Experiment on the catalytic oxidation activity of benzyl alcohol

[0070] The Zn2In2S5 prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were used to conduct experiments on the photocatalytic oxidation (dehydrogenation) of benzyl alcohol to produce benzaldehyde.

[0071] The specific steps of the experiment are as follows:

[0072] 90 mg of the prepared photocatalyst Zn₂In₂S₅ was added to 50 mL of trifluorotoluene containing 52 μL (0.5 mmol) benzyl alcohol in a double-walled quartz reactor. The solution temperature was maintained at 25 °C by circulating water. First, oxygen in the reaction suspension was purged with nitrogen for 20 min, then irradiated under a 300 W xenon lamp for 3 h. The liquid product was analyzed by high-performance gas chromatography (GC). Results are shown below. Figure 4 The results showed that Zn2In2S5-1 in Comparative Example 1 had relatively low conversion rates and selectivity for benzyl alcohol and benzaldehyde, respectively. Although Zn2In2S5-2 in Comparative Example 2 had higher selectivity for benzaldehyde, its BA conversion rate was low. The two-dimensional few-layer photocatalysts Zn2In2S5-3 and Zn2In2S5-4 prepared in Examples 1 and 2 showed very high BA conversion rates and BAD selectivity, especially Zn2In2S5-3 in Example 1. The results indicate that the two-dimensional few-layer photocatalysts Zn2In2S5-3 and Zn2In2S5-4 have good photocatalytic activity for the oxidation of benzyl alcohol under visible light, especially in terms of benzyl alcohol (BD) catalytic conversion rate, where Zn2In2S5-3 is more effective. In contrast, the catalytic activity (benzaldehyde conversion rate) of Zn2In2S5-1 and Zn2In2S5-2 in the Comparative Examples was very low.

[0073] Figure 4 The diagram shows the catalytic oxidation experiments of the (two-dimensional few-layer) photocatalyst Zn2In2S5 in Examples 1 and 2 and Comparative Examples 1 and 2 under visible light, catalyzing the oxidation of a 50 mL solution of trifluorotoluene containing 52 μL (0.5 mmol) benzyl alcohol.

[0074] 2. Catalytic oxidation activity of Zn2In2S5-3 in different solvents for benzyl alcohol

[0075] Following the method described in section 1 above, the two-dimensional few-layer photocatalyst Zn₂In₂S₅₃ prepared in the examples was subjected to catalytic oxidation activity experiments of benzyl alcohol in acetonitrile (CAN), deionized water (DI), and trifluorotoluene (BTF), respectively. The results are shown in [Figure 1]. Figure 5 The results show that the two-dimensional few-layer material Zn2In2S5-3 exhibits the best BAD conversion rate in the selective catalytic oxidation of benzyl alcohol in trifluorotoluene.

[0076] The catalyst Zn₂In₂S₅₃ after the catalytic oxidation experiment was recovered and subjected to XRD analysis. The results were compared with the XRD analysis before the catalytic oxidation experiment. Figure 6The XRD patterns of Zn₂In₂S₅₃ before and after the catalytic oxidation of benzyl alcohol solution under visible light are compared. The figures show that the XRD patterns of the reacted sample are consistent with those of the initially prepared sample, indicating that Zn₂In₂S₅₃ possesses high stability. Figure 7 The image shows a comparison of the infrared spectra of Zn₂In₂S₅₃ before and after photocatalysis. It can be seen from the image that the infrared spectrum after the photocatalytic reaction is consistent with the infrared spectrum of the initially prepared sample. This further demonstrates that sample Zn₂In₂S₅₃ possesses high photocatalytic phase stability.

[0077] The above experimental results show that the two-dimensional few-layer photocatalyst Zn₂In₂S₅-3 synthesized in Example 1 has a good conversion rate for the photocatalytic oxidation of benzyl alcohol to benzaldehyde. The photocatalytic performance of the two-dimensional few-layer Zn₂In₂S₅ was evaluated using 50 mL of trifluorotoluene containing 52 μL (0.5 mmol) benzyl alcohol. The experimental results show that the conversion rate of benzyl alcohol to benzaldehyde within 3 hours can reach over 99%, with a selectivity of approximately 99%, and the average yield of benzaldehyde is 2.83 mmol g. -1 h -1 The Zn₂In₂S₅₁ synthesized using the method in Reference 1 exhibited lower photocatalytic activity than the two-dimensional few-layer photocatalyst Zn₂In₂S₅₃ under the same experimental conditions. Its conversion rate of benzyl alcohol was only 48.8%, almost half that of Zn₂In₂S₅₃, and its selectivity for benzaldehyde was also relatively low at 88.5%. Furthermore, the photocatalytic effects of Zn₂In₂S₅₂ and Zn₂In₂S₅₄ synthesized by changing the water content were also inferior to those of Zn₂In₂S₅₃. Therefore, this indicates that the improved method synthesized the two-dimensional few-layer photocatalyst Zn₂In₂S₅₃ can efficiently catalyze the production of benzaldehyde from benzyl alcohol. Meanwhile, the specific surface area test results show that the specific surface area of ​​the two-dimensional few-layer photocatalyst Zn₂In₂S₅₃ is 90.57 m². 2 The / g indicates that the catalyst has a large number of active sites, providing a strong reference for its efficient catalytic production of benzaldehyde from benzyl alcohol.

[0078] Substrate expansion applications

[0079] Referring to the experimental method for converting benzyl alcohol to benzaldehyde, the two-dimensional few-layer photocatalyst Zn2In2S5-3 prepared in Example 1 was used to conduct photocatalytic oxidation experiments of benzyl alcohol with different substituents under visible light.

[0080] This experiment was used to verify the photocatalytic efficiency of the two-dimensional few-layer photocatalyst Zn₂In₂S₅⁻³ for benzyl alcohol with different substituents. The results are shown in Table 1. The results indicate that the two-dimensional few-layer photocatalyst Zn₂In₂S₅⁻³ exhibits excellent photocatalytic performance for benzyl alcohol with different substituents. Where C% represents the conversion rate of benzyl alcohol, Y% represents the yield of benzaldehyde, and S% represents the selectivity of benzaldehyde.

[0081] Table 1. Expanded experiments with different substituted substrates

[0082]

[0083] Table 1 shows the catalytic effects of the two-dimensional few-layer photocatalyst Zn₂In₂S₅₃ on 10 mmol / L solutions of 4-methoxybenzyl alcohol, p-chlorobenzyl alcohol, p-fluorobenzyl alcohol, and cinnamyl alcohol under visible light and nitrogen atmosphere. The results in Table 1 indicate that the two-dimensional few-layer photocatalyst Zn₂In₂S₅₃ has broad applicability and exhibits excellent photocatalytic performance for benzyl alcohol and cinnamyl alcohol with different substituents under visible light.

Claims

1. An improved method for preparing a two-dimensional few-layer photocatalyst Zn2In2S5, characterized in that, The method comprises the following steps: 1) Dissolving anhydrous ZnAc2, InCl3·4H2O and thioacetamide in deionized water, and stirring the reaction at an oil bath temperature of 80-100℃; 2) After the reaction is completed, naturally cooling to room temperature, and then performing ultrasonic treatment for 0.5-2h; 3) After the ultrasonic treatment is completed, washing, vacuum drying, and obtaining a two-dimensional few-layer photocatalyst Zn2In2S5, The molar mass volume ratio of ZnAc2 to deionized water is 1mmol:(20-50)ml, In step 1), the molar ratio of ZnAc2, InCl3·4H2O and thioacetamide is 2:2:

5.

2. The improved method of claim 1 wherein, In step 1), the stirring reaction is stirred at a constant rotation speed.

3. The improved method of claim 1 or 2, wherein, The stirring reaction is performed at an oil bath temperature of 90℃, and the reaction time is 5h.

4. The improved method of claim 1 wherein, In step 2), the ultrasonic treatment is performed at a frequency of 24kHz for 1h.

5. The improved method of claim 1 wherein, In step 3), the washing is performed with deionized water and anhydrous ethanol alternately for three times, and the drying is performed at a drying temperature of 60℃.

6. The improved method of claim 1 wherein, The two-dimensional few-layer refers to 1-3 layers of sheet layers.

7. The improved method of claim 1 wherein, In step 1), the molar mass volume ratio of ZnAc2 to deionized water is 1mmol:40ml.

8. Use of Zn2In2S5 prepared by the improved method of any one of claims 1-7 for catalytic dehydrogenation of benzyl alcohol, p-chlorobenzyl alcohol or p-fluorobenzyl alcohol to produce benzaldehyde, p-chlorobenzaldehyde or p-fluorobenzaldehyde.

9. Use according to claim 8, characterized in that, The catalytic dehydrogenation is performed in a solvent of trifluorotoluene.

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