Copper sulfide silica double-layer hollow shell structure photocatalyst and its preparation method

Abstract

This invention discloses a copper sulfide-silica double-layer hollow shell photocatalyst and its preparation method, belonging to the field of photocatalyst technology. The copper sulfide-silica double-layer hollow shell photocatalyst of this invention comprises copper sulfide hollow sphere nanoparticles, with the copper sulfide hollow sphere nanoparticles as the core and silica as the shell. The specific preparation method is as follows: preparing copper sulfide hollow nanospheres; preparing a sodium citrate-modified copper sulfide hollow nanosphere suspension; preparing the copper sulfide-silica double-layer hollow shell photocatalyst. The overall preparation method of this invention is simple, with mild reaction conditions, relatively low production cost, and high safety. The prepared copper sulfide hollow spheres have controllable size and good photocatalytic degradation performance of organic pollutants in water. The outer silica shell thickness is controllable and has high stability, which can improve the stability of copper sulfide without reducing the photocatalytic performance of the inner copper sulfide layer, and to a certain extent inhibit its photocorrosion and oxidation.

Description

Technical Field

[0001] This invention belongs to the field of photocatalyst technology, specifically, it relates to a copper sulfide silica double-layer hollow shell structure photocatalyst and its preparation method. Background Technology

[0002] In recent years, with the development of industry, agriculture, and healthcare, as well as changes in people's lifestyles, water pollution has become increasingly serious. At the same time, the sources of pollution are complex; polluted water bodies contain not only inorganic pollutants and harmful microorganisms, but also a large amount of persistent organic pollutants (POPs). POPs are characterized by their high hazard, wide-ranging pollution, long retention time in water, and difficulty in degradation. They can migrate and transform over long distances, accumulate in organisms and the human body through the food chain, and continuously amplify, causing various diseases. Traditional water treatment technologies such as adsorption and biological methods have drawbacks such as high cost and low efficiency, resulting in poor removal of organic pollutants. Photocatalysis, as a green and environmentally friendly advanced oxidation technology, has received widespread attention from water pollution treatment researchers both domestically and internationally.

[0003] Metal sulfides are an important class of semiconductor-based photocatalysts. Quantum confinement occurs when one or more dimensions of a semiconductor nanostructure are close to or smaller than the exciton Bohr radius (the limiting size for maintaining a continuous band structure in a material). Therefore, the band gap can be precisely tuned simply by controlling the particle size without changing the chemical composition of the metal sulfide. Copper sulfide (CuS) has broad application prospects due to its unique optical properties. Furthermore, copper sulfide exhibits different band gap values ​​when existing in different forms, such as copper sulfide microspheres, nanotubes, nanosheets, and nanoparticles, with average band gaps of 2.08, 2.06, 2.16, and 1.88 eV, respectively. However, as a metal sulfide, copper sulfide also suffers from photocorrosion and oxidation, leading to a decrease in its photocatalytic performance. During photocatalysis, copper sulfide reacts with its own generated holes to produce copper ions and elemental sulfur. Simultaneously, under water and oxygen conditions, copper sulfide reacts with oxygen to produce copper oxide and elemental sulfur, resulting in poor recyclability of copper sulfide in water pollution treatment applications. Summary of the Invention

[0004] To overcome the technical problems existing in the background art, this invention proposes a copper sulfide-silica double-layer hollow shell photocatalyst and its preparation method. Utilizing the strong chemical inertness of silica, it is coated onto the surface of copper sulfide, which not only protects the internal copper sulfide and improves its resistance to photocorrosion, but also confines electrons in one component and holes in the other, effectively reducing the recombination rate of electron-hole pairs and enhancing photocatalytic efficiency. Furthermore, the preparation method of this invention has low process requirements and cost, is safe, simple, and easy to implement, and its application in the treatment of organic pollutants in water shows good results.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] Copper sulfide and silica double-layer hollow shell structured photocatalyst: comprising copper sulfide hollow sphere nanoparticles, with copper sulfide hollow sphere nanoparticles as the core and silica as the shell, wherein citrate ions are grafted onto the outer surface of the copper sulfide hollow sphere nanoparticles.

[0007] Furthermore, the diameter of the copper sulfide hollow sphere nanoparticles is 100-1000 nm, and the thickness of the silica shell is 40-100 nm.

[0008] The specific steps for preparing the copper sulfide silica double-layer hollow shell structure photocatalyst are as follows:

[0009] 1) Preparation of copper sulfide hollow nanospheres;

[0010] 2) Citrate groups were grafted onto the surface of copper sulfide hollow nanospheres to prepare sodium citrate-modified copper sulfide hollow nanospheres;

[0011] 3) Coating the surface of sodium citrate-modified copper sulfide hollow nanospheres with silica to prepare a copper sulfide silica double-shell structured photocatalyst.

[0012] Further, the specific preparation steps of step 1) are as follows: a) Dissolve copper nitrate trihydrate in 30-60 mL of solvent, place it in an oil bath and heat and stir; b) Dissolve thioacetamide in 10-40 mL of solvent, place it in an oil bath and heat and stir; c) After both solutions are heated to 50-70℃, remove the copper nitrate solution from the oil bath and slowly pour it into the thioacetamide solution; d) Stir the mixed solution at the same temperature for 10-30 min; e) After the solution cools, centrifuge at 5000-8000 rpm, wash with deionized water and ethanol, and dry in an oven to obtain copper sulfide hollow nanospheres.

[0013] Further, the specific preparation steps of step 2) are as follows: a) Dissolve sodium citrate in 30-60 mL of deionized water to obtain a sodium citrate solution, then weigh 400 mg of copper sulfide hollow nanospheres obtained in step 1) and pour them into the sodium citrate solution, sonicate to fully disperse the copper sulfide and obtain a suspension; b) Place the suspension in an oil bath and stir at 50-70℃ for 8-12 h; c) After the suspension cools, centrifuge and wash with acetone, then redisperse the obtained sodium citrate-modified copper sulfide hollow nanospheres in 20-30 mL of deionized water to obtain a sodium citrate-modified copper sulfide hollow nanosphere suspension.

[0014] Further, the specific preparation steps of step 3) are as follows: a) Take the sodium citrate-modified copper sulfide hollow nanosphere suspension prepared in step 2), weigh hexadecyltrimethylammonium bromide and dissolve it in 150-200 mL of deionized water, then add 100-150 mL of ethanol, stir thoroughly, and then slowly add ammonia water with a mass percentage of 26-28%. After stirring again, sonicate for 30-50 min. After the copper sulfide hollow nanospheres are fully dispersed in the solution, add tetraethyl orthosilicate to the solution dropwise while stirring continuously. React at 20-40℃ for 10-12 h; b) After the reaction is complete, centrifuge at 5000-8000 rpm and wash with deionized water and ethanol; c. Then disperse the product obtained by centrifugation in 60-100 mL of acetone solution in a three-necked flask, reflux in an oil bath at 70-100 °C for 24-72 h to remove hexadecyltrimethylammonium bromide. After the solution cools, centrifuge at 5000-8000 rpm and wash with deionized water and ethanol. Repeat this step three times; d. Finally, place the obtained sample in an oven to dry to obtain the copper sulfide silica double-layer hollow shell structure photocatalyst.

[0015] Preferably, in step 1), the solvent is one or more of deionized water, ethanol, and ethylene glycol, and the stirring speed of the solution is 400-600 rpm.

[0016] Preferably, the mass ratio of copper nitrate trihydrate to thioacetamide is 2 to 4:1.

[0017] Preferably, the mass ratio of sodium citrate to copper sulfide hollow spheres is 5 to 10:1.

[0018] Preferably, the amounts of the sodium citrate-modified copper sulfide hollow sphere suspension, hexadecyltrimethylammonium bromide, ammonia, and tetraethyl orthosilicate are 10–20 mL; 0.5–1 g; 1–5 mL; and 0.1–5 mL, respectively. The beneficial effects of this invention are:

[0019] (1) The preparation of copper sulfide in this invention does not require additional steps to remove the template. The atmosphere and pressure do not need to be controlled during the entire preparation process, and the heating temperature does not exceed 100°C. The method is safe, simple, and inexpensive.

[0020] (2) The size of the copper sulfide silica double-layer hollow shell structure photocatalyst prepared by the method of the present invention is controllable. The diameter of the inner copper sulfide hollow sphere can be adjusted in the range of 100-1000nm by simply changing the type and ratio of solvent. The thickness of the outer silica shell can also be controlled by changing the amount of tetraethyl orthosilicate added.

[0021] (3) The copper sulfide silica double-layer hollow shell structure photocatalyst prepared by the method of the present invention has good catalytic performance. It can generate electron-hole pairs under visible light irradiation, thereby catalyzing water and persulfate to generate free radicals such as hydroxyl radicals, superoxide radicals, and sulfate radicals to oxidize and degrade organic pollutants. For example, the copper sulfide silica double-layer hollow shell structure photocatalyst has a removal efficiency of over 90% for tetracycline hydrochloride and a total organic carbon removal efficiency of up to 40%.

[0022] (4) Compared with pure copper sulfide hollow spheres, the copper sulfide silica double-layer hollow shell structure photocatalyst prepared in this invention maintains its catalytic performance basically unchanged after multiple photocatalytic degradation experiments, and the mass loss is significantly reduced. Attached Figure Description

[0023] Figure 1 Scanning electron microscope (SEM) images of the copper sulfide hollow sphere nanoparticles prepared in Examples 1, 3, 4, 5, 6, and 7.

[0024] Figure 2 Low-magnification and high-magnification transmission electron microscope images of the copper sulfide hollow sphere nanoparticles prepared in Example 3;

[0025] Figure 3 Infrared spectra of copper sulfide hollow sphere nanoparticles before and after sodium citrate modification prepared in Example 1;

[0026] Figure 4 Low-magnification and high-magnification transmission electron microscope images of the copper sulfide silica double-layer hollow shell structure photocatalyst prepared in Example 1;

[0027] Figure 5 The following are the effects of the copper sulfide-silica double-layer hollow shell structure photocatalyst: (a. Cyclic performance diagram of the removal efficiency of copper sulfide hollow spheres and copper sulfide-silica double-layer hollow shell structure photocatalyst for tetracycline hydrochloride; b. Total organic carbon removal efficiency and mass loss diagram of copper sulfide hollow spheres and copper sulfide-silica double-layer hollow shell structure photocatalyst for tetracycline hydrochloride). Detailed Implementation

[0028] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0029] Example 1

[0030] The preparation steps of a copper sulfide silica double-layer hollow shell structure photocatalyst are as follows:

[0031] 1) Preparation of copper sulfide hollow nanospheres:

[0032] a. Weigh 4g of copper nitrate trihydrate (Cu(NO3)2·3H2O) and dissolve it in 50mL of deionized water. After stirring evenly, cover the mouth of the beaker with a layer of plastic wrap, then place the beaker in an oil bath and heat it while stirring at 600rpm. b. Weigh 2g of thioacetamide (TAA) and dissolve it in 30mL of deionized water. After stirring evenly, cover the mouth of the beaker with a layer of plastic wrap, then place the beaker in an oil bath and heat it while stirring at 600rpm. c. After both solutions have been heated to 50℃... Remove the copper nitrate solution from the oil bath, remove the plastic wrap, and then slowly pour it into the thioacetamide solution (with the plastic wrap removed). At this point, the solution color quickly changes from yellowish-brown to black. d. Cover with plastic wrap and continue stirring the mixture at 600 rpm for 30 minutes at the same temperature. e. After the solution cools, centrifuge at 5000 rpm, wash with deionized water and ethanol, and then dry in an oven to obtain copper sulfide hollow nanospheres. The mass ratio of copper nitrate trihydrate to thioacetamide is 2:1.

[0033] 2) Preparation of sodium citrate-modified copper sulfide hollow nanosphere suspension:

[0034] a) Weigh 2g of sodium citrate (C6H5Na3O7) and dissolve it in 60mL of deionized water to obtain a sodium citrate solution. Then weigh 400mg of copper sulfide hollow nanospheres obtained in step 1) and pour them into the sodium citrate solution. Sonicate the solution to fully disperse the copper sulfide and obtain a suspension. b) Place the suspension in an oil bath and stir at 50℃ for 12h. c) After cooling, centrifuge and wash with acetone. Redisperse the obtained sodium citrate-modified copper sulfide hollow nanospheres in 20mL of deionized water to obtain a sodium citrate-modified copper sulfide hollow nanosphere suspension. The mass ratio of sodium citrate to copper sulfide hollow nanospheres is 5:1.

[0035] The infrared spectrum of the sodium citrate-modified copper sulfide hollow sphere nanoparticles prepared by the above method is shown in the figure. Figure 3 As shown, from Figure 3 As can be seen, after treatment with sodium citrate, carboxyl groups were successfully grafted onto the surface of copper sulfide. The presence of these groups facilitates the dispersibility of copper sulfide in water, enhances the adsorption of tetraethyl orthosilicate on its surface, and provides a possibility for the growth of silica.

[0036] 3) Preparation of copper sulfide silica double-layer hollow shell structure photocatalyst:

[0037] a) Take 20 mL of the sodium citrate-modified copper sulfide hollow nanosphere suspension prepared in step 2), then weigh 1 g of hexadecyltrimethylammonium bromide (CTAB) and dissolve it in 200 mL of deionized water. Add 150 mL of ethanol, stir thoroughly, and then slowly add 3 mL of ammonia water (26-28% wt%) to the solution. Stir again and sonicate for 30 min. After the copper sulfide hollow nanospheres are fully dispersed in the solution, add 2 mL of tetraethyl orthosilicate (TEOS) to the solution while stirring, and continue stirring. React at 20 °C for 1 minute. b) After the reaction is complete, centrifuge at 5000 rpm and wash with deionized water and ethanol; c) Then disperse the product obtained by centrifugation in 60 mL of acetone solution in a three-necked flask, reflux at 70 °C for 24 h in an oil bath to remove hexadecyltrimethylammonium bromide. After the solution cools, centrifuge at 8000 rpm and wash with deionized water and ethanol, repeating the reflux washing three times; d) Finally, place the obtained sample in an oven to dry to obtain the copper sulfide silica double-layer hollow shell structure photocatalyst.

[0038] Low-magnification and high-magnification transmission electron microscope images of the copper sulfide silica double-layer hollow shell structured photocatalyst prepared in this embodiment are shown below. Figure 4 As shown, in (a), a layer of silicon dioxide shell can be seen on the surface of the hollow copper sulfide sphere. At the same time, the phase of copper sulfide does not change after the coating. In (b), the typical lattice of hexagonal copper sulfide can still be observed.

[0039] Example 2

[0040] The preparation steps of a copper sulfide silica double-layer hollow shell structure photocatalyst are as follows:

[0041] 1) Preparation of copper sulfide hollow nanospheres:

[0042] a) Weigh 3.5g of copper nitrate trihydrate (Cu(NO3)2·3H2O) and dissolve it in 40mL of ethylene glycol. After stirring evenly, cover the mouth of the beaker with a layer of plastic wrap, then place the beaker in an oil bath and heat it while stirring at 500rpm. b) Weigh 1.5g of thioacetamide (TAA) and dissolve it in 40mL of ethylene glycol. After stirring evenly, cover the mouth of the beaker with a layer of plastic wrap, then place the beaker in an oil bath and heat it while stirring at 500rpm. c) Heat both solutions to 70℃. Then, remove the copper nitrate solution from the oil bath, remove the plastic wrap, and slowly pour it into the thioacetamide solution (with the plastic wrap removed). At this time, the solution color quickly changes from yellowish-brown to black. d. Cover with plastic wrap and continue stirring the mixed solution at 500 rpm for 20 minutes at the same temperature. e. After the solution cools, centrifuge at 6000 rpm, wash with deionized water and ethanol, and dry in an oven to obtain copper sulfide hollow nanospheres. The mass ratio of copper nitrate trihydrate to thioacetamide is 7:3.

[0043] 2) Preparation of sodium citrate-modified copper sulfide hollow nanosphere suspension:

[0044] a) Weigh 1.5g of sodium citrate (C6H5Na3O7) and dissolve it in 30mL of deionized water to obtain a sodium citrate solution. Then weigh 400mg of copper sulfide hollow nanospheres obtained in step 1) and pour them into the sodium citrate solution. Sonicate to fully disperse the copper sulfide and obtain a suspension. b) Place the suspension in an oil bath and stir at 70℃ for 12h. c) After cooling, centrifuge and wash with acetone. Redisperse the obtained sodium citrate-modified copper sulfide hollow nanospheres in 20mL of deionized water to obtain a sodium citrate-modified copper sulfide hollow nanosphere suspension. The mass ratio of sodium citrate to copper sulfide hollow nanospheres is 15:4.

[0045] 3) Preparation of copper sulfide silica double-layer hollow shell structure photocatalyst:

[0046] a) Take 10 mL of the sodium citrate-modified copper sulfide hollow nanosphere suspension prepared in step 2), then weigh 0.75 g of cetyltrimethylammonium bromide (CTAB) and dissolve it in 150 mL of deionized water. Add 150 mL of ethanol, stir thoroughly, and then slowly add 1 mL of ammonia water (26-28% wt%) to the solution. Stir again and sonicate for 40 min. After the copper sulfide hollow nanospheres are fully dispersed in the solution, add 0.5 mL of tetraethyl orthosilicate (TEOS) to the solution while stirring, and continue stirring at 30 °C. a) React for 12 hours; b) After the reaction is complete, centrifuge at 6000 rpm and wash with deionized water and ethanol; c) Then disperse the product obtained by centrifugation in 80 mL of acetone solution in a three-necked flask, reflux at 80 °C in an oil bath for 36 hours to remove hexadecyltrimethylammonium bromide. After the solution cools, centrifuge at 6000 rpm and wash with deionized water and ethanol, repeating the reflux washing three times; d) Finally, place the obtained sample in an oven to dry to obtain the copper sulfide silica double-layer hollow shell structure photocatalyst.

[0047] Example 3

[0048] The preparation steps of a copper sulfide silica double-layer hollow shell structure photocatalyst are as follows:

[0049] 1) Preparation of copper sulfide hollow nanospheres:

[0050] a) Weigh 4.75g of copper nitrate trihydrate (Cu(NO3)2·3H2O) and dissolve it in 60mL of ethanol. After stirring well, cover the mouth of the beaker with a layer of plastic wrap, then place the beaker in an oil bath and heat it while stirring at 550rpm. b) Weigh 1.58g of thioacetamide (TAA) and dissolve it in 40mL of ethanol. After stirring well, cover the mouth of the beaker with a layer of plastic wrap, then place the beaker in an oil bath and heat it while stirring at 550rpm. c) After both solutions have been heated to 45℃... Remove the copper nitrate solution from the oil bath, remove the plastic wrap, and then slowly pour it into the thioacetamide solution (with the plastic wrap removed). At this point, the solution color quickly changes from yellowish-brown to black. d. Cover with plastic wrap and continue stirring the mixture at 550 rpm for 30 minutes at the same temperature. e. After the solution cools, centrifuge at 5000 rpm, wash with deionized water and ethanol, and then dry in an oven to obtain copper sulfide hollow nanospheres. The mass ratio of copper nitrate trihydrate to thioacetamide is 3:1.

[0051] The copper sulfide hollow sphere nanoparticles obtained in the above preparation steps were subjected to electron microscopy, and the results are as follows: Figure 2As shown in the low- and high-magnification transmission electron microscope (TEM) images, it can be seen that the prepared copper sulfide spheres have hollow cavities. Measurements show that the typical interplanar spacings of six-phase copper sulfide are 0.3048 nm, 0.2740 nm, and 0.2813 nm in the high-magnification TEM image.

[0052] 2) Preparation of sodium citrate-modified copper sulfide hollow nanosphere suspension:

[0053] a) Weigh 3g of sodium citrate (C6H5Na3O7) and dissolve it in 50mL of deionized water to obtain a sodium citrate solution. Then weigh 400mg of copper sulfide hollow nanospheres obtained in step 1) and pour them into the sodium citrate solution. Sonicate to fully disperse the copper sulfide and obtain a suspension. b) Place the suspension in an oil bath and stir at 45℃ for 12h. c) After cooling, centrifuge and wash with acetone. Redisperse the obtained sodium citrate-modified copper sulfide hollow nanospheres in 30mL of deionized water to obtain a sodium citrate-modified copper sulfide hollow nanosphere suspension. The mass ratio of sodium citrate to copper sulfide hollow nanospheres is 15:2.

[0054] 3) Preparation of copper sulfide silica double-layer hollow shell structure photocatalyst:

[0055] a) Take 10 mL of the sodium citrate-modified copper sulfide hollow nanosphere suspension prepared in step 2), then weigh 0.55 g of cetyltrimethylammonium bromide (CTAB) and dissolve it in 175 mL of deionized water. Add 200 mL of ethanol, stir thoroughly, and then slowly add 2 mL of ammonia water (26-28% wt%) to the solution. Stir again and sonicate for 30 min. After the copper sulfide hollow nanospheres are fully dispersed in the solution, add 4 mL of tetraethyl orthosilicate (TEOS) to the solution while stirring, continue stirring, and incubate at 35 °C. a) After the reaction is complete, centrifuge at 7500 rpm and wash with deionized water and ethanol; b) Then disperse the product obtained by centrifugation in 80 mL of acetone solution in a three-necked flask, reflux at 90 °C in an oil bath for 12 h to remove hexadecyltrimethylammonium bromide. After the solution cools, centrifuge at 7500 rpm and wash with deionized water and ethanol, repeating the reflux washing three times; c) Finally, place the obtained sample in an oven to dry to obtain the copper sulfide silica double-layer hollow shell structure photocatalyst.

[0056] Example 4

[0057] The steps in this embodiment are basically the same as those in Example 1. The difference is that in this embodiment, the solvents used for copper nitrate trihydrate and thioacetamide are water and ethylene glycol in a volume ratio of 1:1.

[0058] Example 5

[0059] The steps in this embodiment are basically the same as those in Example 1. The difference is that the solvents used for copper nitrate trihydrate and thioacetamide in this embodiment are water and ethylene glycol in a volume ratio of 3:1.

[0060] Example 6

[0061] The steps in this embodiment are basically the same as those in Example 1. The difference is that the solvents used for copper nitrate trihydrate and thioacetamide in this embodiment are water and ethylene glycol in a volume ratio of 1:3.

[0062] Example 7

[0063] The steps in this embodiment are basically the same as those in Example 1. The difference is that in this embodiment, the solvents used for copper nitrate trihydrate and thioacetamide are water and ethanol in a volume ratio of 1:1.

[0064] Experimental Analysis

[0065] The copper sulfide hollow sphere nanoparticles prepared in Examples 1, 3, 4, 5, 6, and 7 were subjected to electron microscopy scanning, and the results are as follows: Figure 1 As shown, statistical calculations indicate that the average sizes of the copper sulfide hollow spheres corresponding to (a), (b), (c), (d), (e), and (f) in the figure are 821.96 nm, 196.64 nm, 494.02 nm, 851.14 nm, 328.29 nm, and 462.26 nm, respectively. Figure 1 It is known that different types and proportions of solvents will affect the size of hollow copper sulfide spheres, meaning that the size of hollow copper sulfide spheres can be adjusted by changing the type and proportion of solvents.

[0066] The copper sulfide silica double-layer hollow shell structure photocatalyst prepared in this invention was applied to water pollution treatment, exhibiting good catalytic performance, effectively degrading free radicals in organic pollutants, and demonstrating stable performance. Specifically, the catalytic performance of the copper sulfide silica double-layer hollow shell structure photocatalyst and copper sulfide hollow spheres prepared in Example 1 of this invention on tetracycline hydrochloride was experimentally tested, and the catalytic effects were as follows: Figure 5 As shown in Figure (a), the removal efficiency of copper sulfide hollow spheres and copper sulfide silica double-layer hollow shell photocatalysts for tetracycline hydrochloride both reached over 90%, and the removal efficiency remained basically unchanged after 7 cycles. Figure (b) also shows that the total organic carbon removal efficiency of copper sulfide hollow spheres and copper sulfide silica double-layer hollow shell photocatalysts for tetracycline hydrochloride was around 40%. After each cycle, the remaining mass of the copper sulfide silica double-layer hollow shell photocatalyst was greater than that of the copper sulfide hollow spheres. This indicates that the silica coating inhibited the photocorrosion phenomenon of copper sulfide to a certain extent during the photocatalytic process, and the inert silica did not affect the good photocatalytic performance of copper sulfide.

[0067] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A copper sulfide silica double-layer hollow shell structure photocatalyst, characterized in that: The aforementioned double-layer hollow shell structure photocatalyst comprises copper sulfide hollow sphere nanoparticles, with copper sulfide hollow sphere nanoparticles as the core and silicon dioxide as the shell, and citrate ions grafted onto the outer surface of the copper sulfide hollow sphere nanoparticles.

2. The copper sulfide silica double-layer hollow shell structure photocatalyst according to claim 1, characterized in that: The diameter of the copper sulfide hollow sphere nanoparticles is 100-1000 nm, and the thickness of the silica shell is 40-100 nm.

3. The method for preparing the copper sulfide silica double-layer hollow shell structure photocatalyst according to claim 1 or 2, characterized in that: The specific preparation steps are as follows: 1) Preparation of copper sulfide hollow nanospheres; 2) Citrate groups were grafted onto the surface of copper sulfide hollow nanospheres to prepare sodium citrate-modified copper sulfide hollow nanospheres; 3) Coating the surface of sodium citrate-modified copper sulfide hollow nanospheres with silica to prepare a copper sulfide silica double-shell structure photocatalyst.

4. The method for preparing the copper sulfide silica double-layer hollow shell structure photocatalyst according to claim 3, characterized in that: Step 1) The specific preparation steps are as follows: a) Dissolve copper nitrate trihydrate in 30-60 mL of solvent, place it in an oil bath and heat and stir; b) Dissolve thioacetamide in 10-40 mL of solvent, place it in an oil bath and heat and stir; c) After both solutions are heated to 50-70℃, remove the copper nitrate solution from the oil bath and slowly pour it into the thioacetamide solution; d) Stir the mixed solution at the same temperature for 10-30 min; e) After the solution cools, centrifuge at 5000-8000 rpm, wash with deionized water and ethanol, and dry in an oven to obtain copper sulfide hollow nanospheres.

5. The method for preparing the copper sulfide silica double-layer hollow shell structure photocatalyst according to claim 3, characterized in that: Step 2) The specific preparation steps are as follows: a. Dissolve sodium citrate in 30-60 mL of deionized water to obtain sodium citrate solution, then weigh 400 mg of copper sulfide hollow nanospheres obtained in step 1) and pour them into sodium citrate solution. Ultrasonic treatment is performed to fully disperse copper sulfide to obtain a suspension. b. Place the suspension in an oil bath and stir at 50-70℃ for 8-12 hours; c. After the suspension cools, centrifuge and wash with acetone. Redisperse the obtained sodium citrate-modified copper sulfide hollow nanospheres in 20-30 mL of deionized water to obtain a sodium citrate-modified copper sulfide hollow nanosphere suspension.

6. The method for preparing the copper sulfide silica double-layer hollow shell structure photocatalyst according to claim 3, characterized in that: Step 3) The specific preparation steps are as follows: a) Take the sodium citrate-modified copper sulfide hollow nanosphere suspension prepared in step 2), weigh hexadecyltrimethylammonium bromide and dissolve it in 150-200 mL of deionized water, then add 100-150 mL of ethanol, stir thoroughly, and then slowly add ammonia water with a mass percentage of 26-28%. After stirring again, sonicate for 30-50 min. After the copper sulfide hollow nanospheres are fully dispersed in the solution, add tetraethyl orthosilicate to the solution dropwise while stirring continuously. React at 20-40℃ for 10-12 h; b) Wait for the reaction to proceed... After completion, centrifuge at 5000-8000 rpm and wash with deionized water and ethanol; c. Then disperse the centrifuged product in 60-100 mL of acetone solution in a three-necked flask, reflux in an oil bath at 70-100 °C for 24-72 h to remove hexadecyltrimethylammonium bromide. After the solution cools, centrifuge at 5000-8000 rpm and wash with deionized water and ethanol. Repeat this step three times; d. Finally, place the obtained sample in an oven to dry to obtain the copper sulfide silica double-layer hollow shell structure photocatalyst.

7. The method for preparing the copper sulfide silica double-layer hollow shell structure photocatalyst according to claim 4, characterized in that: The solvent is one or more of deionized water, ethanol, and ethylene glycol, and the stirring speed of the solution is 400-600 rpm.

8. The method for preparing the copper sulfide silica double-layer hollow shell structure photocatalyst according to claim 4, characterized in that: The mass ratio of copper nitrate trihydrate to thioacetamide is 2-4:

1.

9. The method for preparing the copper sulfide silica double-layer hollow shell structure photocatalyst according to claim 5, characterized in that: The mass ratio of sodium citrate to copper sulfide hollow spheres is 5-10:

1.

10. The method for preparing the copper sulfide silica double-layer hollow shell structure photocatalyst according to claim 6, characterized in that: The amounts of the sodium citrate-modified copper sulfide hollow sphere suspension, hexadecyltrimethylammonium bromide, ammonia, and tetraethyl orthosilicate are 10–20 mL, 0.5–1 g, 1–5 mL, and 0.1–5 mL, respectively.

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