A heterostructured Cu2S / Cu9S5 nanoparticle, its preparation method and application

Abstract

This invention relates to a heterostructured Cu₂S / Cu₉S₅ nanoparticle, its preparation method, and its applications, belonging to the field of photocatalysis technology. A mixture of CuCl₂·2H₂O, a sulfur source, and ethylene glycol is continuously heated and stirred to form DESs. The DESs are then placed in a microwave reactor for microwave heating and reaction, followed by cooling to obtain the heterostructured Cu₂S / Cu₉S₅ nanoparticles. The preparation process of this invention is simple, environmentally friendly, exhibits tight interfacial coupling, excellent stability, and absorbs visible light. The resulting heterostructured Cu₂S / Cu₉S₅ nanoparticles have regular morphology and good crystal structure and photocatalytic activity.

Description

Technical Field

[0001] This invention relates to the field of photocatalysis technology, and in particular to a heterostructure Cu2S / Cu9S5 nanoparticle, its preparation method and application. Background Technology

[0002] With continuous societal progress and the ongoing exploitation of natural resources, energy crises and environmental pollution have become increasingly prominent, significantly impacting human quality of life and the living environment. In recent years, photocatalysis technology, as a means of utilizing inexhaustible and sustainable solar energy, has experienced rapid development and is considered a potential solution to the energy crisis and environmental pollution problems. This technology, through sustainable development strategies, can completely degrade harmful organic pollutants into harmless carbon dioxide and water. Simultaneously, hydrogen, as a clean energy carrier, can be efficiently produced through water splitting. Constructing photocatalysts with high stability and high activity is a key step in achieving excellent photocatalytic performance. An ideal multifunctional photocatalyst should exhibit superior catalytic activity in both environmental purification and clean energy production.

[0003] Transition metal sulfide semiconductors, especially nanoscale copper sulfides (Cu₂S, CuS, Cu₂S), 1.8 Cu2S, with its numerous advantages such as an ideal p-type bandgap and narrow band gap, has attracted widespread attention in the field of photocatalysis due to its excellent solar energy absorption performance. For example, Cu2S nanomaterials with narrow band gap characteristics have shown potential applications in solar energy conversion (or batteries), photocatalysis, biosensors, and photoelectric conversion devices. Furthermore, CuS's potential applications in photoinduced catalysis, sensor technology, and as a cathode material for lithium-ion batteries are also noteworthy. However, numerous studies have shown that single copper sulfide materials have defects, including low solar energy conversion efficiency, insufficient photocatalytic activity, or poor short-term stability.

[0004] Studies have found that constructing copper sulfide heterostructures can significantly enhance light absorption and improve charge separation efficiency. However, the preparation processes of most composite materials currently involve multiple steps or complex procedures, leading to insufficient heterointerface stability and consequently affecting the separation stability of photogenerated carriers during photocatalysis. Traditional metal sulfides, such as CdS, exhibit instability under light conditions and are susceptible to photocorrosion, releasing harmful Cd ions into water. Although many sulfides exhibit good photocatalytic activity in the visible light region, their environmental friendliness remains questionable. Furthermore, TiO2 is considered a potential material for forming stable heterostructures with copper sulfide. However, given the wide band gap of TiO2 (2.8 eV for rutile and 3.2 eV for anatase), its absorption and catalytic activity for visible light are not ideal. Therefore, developing copper sulfide-related heterostructures with excellent structural stability and photocatalytic activity remains a pressing scientific challenge. Thus, there is an urgent need to develop a new synthetic strategy for preparing environmentally friendly, tightly coupled, highly stable, and visible-light-absorbing multifunctional photocatalysts. Summary of the Invention

[0005] To address the above technical problems, this invention provides heterostructured Cu₂S / Cu₉S₅ nanoparticles, their preparation method, and applications. This invention utilizes a hydrogen-bonded network structure in a low-solubility solvent, ensuring uniform dispersion among the components. Furthermore, microwave solid-state processing can decompose the solvent in a short time, allowing for in-situ growth of different components with tight coupling. Therefore, the in-situ preparation process is simple, environmentally friendly, produces tightly coupled phase interfaces, exhibits excellent stability, and can absorb visible light. The heterostructured Cu₂S / Cu₉S₅ nanoparticles obtained by this invention possess excellent photocatalytic activity. The Cu₂S / Cu₉S₅ synthesized by this invention has a band gap of less than 2 eV, enabling catalytic reactions under visible light.

[0006] The first objective of this invention is to provide a method for preparing heterostructured Cu2S / Cu9S5 nanoparticles, comprising the following steps: A mixture of copper salt, sulfur source and ethylene glycol is taken and continuously heated and stirred to form DESs; The DESs were placed in a microwave solid-phase reactor and subjected to microwave heating reaction. After cooling, the heterostructured Cu2S / Cu9S5 nanoparticles were obtained.

[0007] In some embodiments of the present invention, the copper salt is selected from one or more of CuCl2·2H2O, Cu(NO3)2, or CuSO4.

[0008] In some embodiments of the present invention, the molar ratio of the copper salt, the sulfur source and the ethylene glycol is 1:(1~2):(1~2).

[0009] In some embodiments of the present invention, the sulfur source includes one or more of thiourea, methylthiourea, and thioacetamide.

[0010] In some embodiments of the present invention, the temperature for continuous heating and stirring is 60~100 ℃, and the time is 5~30 min.

[0011] In some embodiments of the present invention, the power of the microwave heating reaction is 1200~1800 W, the temperature is 180~300℃, and the time is 2~10 min.

[0012] The second objective of this invention is to provide a heterostructured Cu2S / Cu9S5 nanoparticle, prepared by the aforementioned preparation method.

[0013] A third objective of this invention is to provide the application of the heterostructured Cu2S / Cu9S5 nanoparticles in photocatalytic hydrogen evolution.

[0014] In some embodiments of the present invention, the light source for photocatalytic hydrogen evolution is: a xenon lamp, PM 1.5, 50~120 mW / cm². -2 ; It also includes sacrificial reagents: concentrations of 0.15–0.35 mol / L. -1 Sodium sulfide with a concentration of 0.15~0.35 mol L -1 A mixed solution of sodium sulfite; The concentration of the heterostructured Cu2S / Cu9S5 nanoparticles is 0.3~1.5 mg / mL; The specific operation of the photocatalytic hydrogen evolution is as follows: First, a mixed solution of sacrificial reagents—sodium sulfide and sodium sulfite—of a certain concentration is prepared and placed in the dark. The photocatalytic water splitting hydrogen production experiment is carried out in a 250 mL glass reactor. 100 mg of the heterostructured Cu2S / Cu9S5 nanoparticle photocatalyst is weighed and added to 100 mL of the prepared sacrificial reagent solution. It is then uniformly dispersed by ultrasonic treatment, and subsequently connected to the photocatalytic generation device system (the light source is a xenon lamp, PM 1.5, 100 mW cm⁻¹). -2 The vacuum pump was turned on to perform a vacuuming operation to remove air from the system. After the light source was turned on, the concentration of hydrogen gas generated was detected by online sampling every 30 minutes using a gas chromatograph.

[0015] The technical solution of the present invention has the following advantages compared with the prior art: This invention utilizes a hydrogen-bonded network structure in a low-solubility solvent to ensure uniform dispersion of the components. Furthermore, microwave solid-state processing can decompose the solvent in a short time, allowing different components to grow in situ and couple tightly. The preparation process is simple, environmentally friendly, produces tightly coupled phase interfaces, exhibits excellent stability, and absorbs visible light. The resulting heterostructured Cu2S / Cu9S5 nanoparticles have regular morphology and good crystal structure. Attached Figure Description

[0016] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein... Figure 1 SEM image of the heterostructure Cu2S / Cu9S5 nanoparticles prepared in Example 1 of this invention.

[0017] Figure 2 The XRD pattern of the heterostructure Cu2S / Cu9S5 nanoparticles prepared in Example 1 of this invention.

[0018] Figure 3 The photocatalytic hydrogen evolution performance curves of the heterostructured Cu2S / Cu9S5 nanoparticles prepared in Examples 1-3 of this invention are shown.

[0019] Figure 4 The photocatalytic degradation performance curves of the heterostructured Cu2S / Cu9S5 nanoparticles prepared in Examples 1-3 of this invention are shown. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0021] Example 1 Accurately weigh CuCl2·2H2O, thiourea, and ethylene glycol in a molar ratio of 1:1:1, and continuously stir in an oil bath at 70 °C to form DESs; take 5 mL of DESs and place it in a crucible, then transfer it to a microwave reactor, setting the power to 1500 W and the reaction temperature to 240 °C. o C, heating time 4 min, followed by furnace cooling, to obtain the heterostructured Cu2S / Cu9S5 nanoparticles.

[0022] The morphology and structure of the heterostructured Cu2S / Cu9S5 nanoparticles were characterized. SEM was used to observe the morphology, while XRD and XPS were used to identify the composition and crystal form. The results are shown in [Figure number missing]. Figures 1-2 .

[0023] Figure 1The image shows a SEM image of the heterostructured Cu2S / Cu9S5 nanoparticles prepared in Example 1 of this invention. As can be seen from the image, the prepared material is a nanosheet structure. Figure 2 The XRD pattern of the heterostructure Cu2S / Cu9S5 nanoparticles prepared in Example 1 of the present invention shows that the sample contains Cu2S / Cu9S5 composite material.

[0024] Example 2 Accurately weigh CuCl2·2H2O, thiourea, and ethylene glycol in a molar ratio of 1:2:2, and continuously stir in an oil bath at 70 ℃ to form DESs; place 5 mL of DESs into a crucible, transfer it to a microwave reactor, set the power to 1500 W, the reaction temperature to 240 ℃, the heating time to 4 min, and cool with the furnace to obtain heterostructured Cu2S / Cu9S5 nanoparticles.

[0025] Example 3 Accurately weigh CuCl2·2H2O, thiourea, and ethylene glycol in a molar ratio of 1:1:2, and continuously stir in an oil bath at 70 ℃ to form DESs; place 5 mL of DESs into a crucible, transfer it to a microwave reactor, set the power to 1500 W, the reaction temperature to 240 ℃, the heating time to 4 min, and cool with the furnace to obtain heterostructured Cu2S / Cu9S5 nanoparticles.

[0026] Performance testing

[0027] 1. The heterostructured Cu2S / Cu9S5 nanoparticles obtained in Examples 1-3 of this invention were subjected to photocatalytic hydrogen evolution experiments. The specific experiments are as follows: First, a sacrificial reagent with a concentration of 0.25 mol·L⁻¹ was prepared. -1 Sodium sulfide with a concentration of 0.35 mol·L⁻¹ -1 A mixed solution of sodium sulfite was prepared and placed in the dark. The photocatalytic water splitting for hydrogen production experiment was conducted in a 250 mL glass reactor. 100 mg of the prepared heterostructured Cu₂S / Cu₉S₅ nanoparticle photocatalyst was weighed and added to 100 mL of a prepared sacrificial reagent solution. The solution was then ultrasonically dispersed to obtain a 1 mg / mL heterostructured Cu₂S / Cu₉S₅ nanoparticle photocatalyst dispersant. This dispersant was then connected to the photocatalytic generation device system (the light source was a xenon lamp, PM₁.₅, 100 mW cm⁻¹). -2 The vacuum pump was turned on to perform a vacuuming operation to remove air from the system. After turning on the light source, online sampling was performed every 30 minutes using a gas chromatograph to detect the concentration of generated hydrogen gas. Experimental results are shown below. Figure 3 .

[0028] Figure 3The images show the photocatalytic hydrogen evolution effect of the heterostructure Cu2S / Cu9S5 nanoparticles prepared in Examples 1-3 of this invention. As can be seen from the hydrogen evolution curves, the synthesized heterostructure Cu2S / Cu9S5 nanoparticles have a good hydrogen evolution effect.

[0029] 2. An experiment was conducted on the photocatalytic degradation of organic pollutants using the heterostructure Cu2S / Cu9S5 nanoparticles obtained in Examples 1-3 of this invention. The specific experiment is as follows: First, prepare 1 L of 10 ppm methylene blue solution. Accurately weigh 50 mg of the prepared heterostructure Cu2S / Cu9S5 nanoparticle sample and measure 100 mL of the prepared methylene blue solution. Add the sample to the methylene blue solution, disperse ultrasonically, and stir in the dark for 30 min to reach adsorption-desorption equilibrium. After the dark treatment, centrifuge 3 mL of the solution and collect the supernatant. Turn on the light source and centrifuge 3 mL of the solution at regular intervals until the solution becomes colorless.

[0030] Figure 4 The images show the photocatalytic degradation effect of the heterostructure Cu2S / Cu9S5 nanoparticles prepared in Examples 1-3 of this invention on methylene blue. As can be seen from the degradation curves, the synthesized heterostructure Cu2S / Cu9S5 nanoparticles all have good degradation effects.

[0031] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing heterostructured Cu2S / Cu9S5 nanoparticles, characterized in that, Includes the following steps: Take a mixture of CuCl2·2H2O, sulfur source and ethylene glycol, and heat and stir continuously to form DESs; The DESs were placed in a microwave solid-phase reactor and subjected to microwave heating reaction. After cooling, the heterostructured Cu2S / Cu9S5 nanoparticles were obtained.

2. The preparation method according to claim 1, characterized in that, The molar ratio of CuCl2·2H2O, sulfur source and ethylene glycol is 1:(1~2):(1~2).

3. The preparation method according to claim 1, characterized in that, The sulfur source includes one or more of thiourea and thioacetamide.

4. The preparation method according to claim 1, characterized in that, The temperature for continuous heating and stirring is 60~100℃, and the time is 5~30 min.

5. The preparation method according to claim 1, characterized in that, The microwave heating reaction has a power of 1200~1800 W, a temperature of 180~300 ℃, and a time of 2~10 min.

6. A heterostructured Cu2S / Cu9S5 nanoparticle, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 5.

7. The application of the heterostructure Cu2S / Cu9S5 nanoparticles described in claim 6 in photocatalytic hydrogen evolution.

8. The application according to claim 7, characterized in that, The light source for the photocatalytic hydrogen evolution is a xenon lamp, PM 1.5, 50~120 mW cm⁻¹. -2 ; It also includes sacrificial reagents: concentrations of 0.15–0.35 mol / L. -1 Sodium sulfide with a concentration of 0.15~0.35 mol L -1 A mixed solution of sodium sulfite; The concentration of the heterostructured Cu2S / Cu9S5 nanoparticles is 0.3~1.5 mg / mL.

9. The application of the heterostructure Cu2S / Cu9S5 nanoparticles as described in claim 6 in the photocatalytic degradation of organic pollutants.

10. The application according to claim 9, characterized in that, The organic pollutants include one or more of methylene blue, rhodamine B, and Congo red.

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