A method for preparing defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres

Abstract

A method for preparing defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres relates to a method for preparing defect-engineered hollow mesoporous nanomaterials. The present invention aims to address the problems of existing metal sulfide nanoparticles, such as high electron-hole pair binding efficiency, poor photoresponse and catalytic performance, and uneven catalyst morphology and large size. The method includes the following steps: 1. Prepare a polyvinyl pyrrolidone solution; 2. Prepare a light yellow copper oxide suspension; 3. Prepare hollow mesoporous copper sulfide nanospheres; and 4. Prepare defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres. The present invention is used to prepare defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres.

Description

Technical Field

[0001] The invention relates to a method for preparing defect-engineered hollow mesoporous nanomaterials. Background Art

[0002] Defect engineering is considered to be an effective method to improve the electronic structure and physicochemical properties of materials and has been widely used. The controllable structural defects caused by the embedding of impurity atoms or impurity ions into the crystal lattice can not only effectively promote ion diffusion and charge transfer, but also provide more storage sites / adsorption sites / active sites for metal ions or intermediates, and are conducive to maintaining the structural flexibility and stability of the material.

[0003] Mesoporous materials have unique structures, including high specific surface area, large pore volume, adjustable pore size, and controllable morphology. They exhibit excellent properties in processes such as adsorption, catalysis, and energy storage. For example, a high specific surface area increases reactive sites, a large pore size improves the transport efficiency of reactants and products, and the nanopore walls exhibit a small size effect. Introducing a hollow structure into a mesoporous material not only imbues the material with the advantages of mesopores, but also provides a controllable cavity, fully utilizing both the inside and the outside, greatly improving its utilization rate and application effect. Functional composite materials can be obtained by compounding with other materials, surface modification with organic or inorganic molecules, and loading molecules, thereby achieving greater synergistic effects.

[0004] Tin disulfide is a two-dimensional van der Waals semiconductor material with excellent photoelectric properties. It is non-toxic, environmentally friendly, abundant, and easy to prepare. As a metal sulfide with a suitable band gap position, tin disulfide has excellent optical properties and a high absorption coefficient, and is considered a very promising functional material. Enhancing the material's absorption of longer wavelength light, improving the separation efficiency of photoinduced carriers, and improving the efficiency of surface catalytic reactions are still essential to achieve better results in applications such as photocatalysis, energy storage, and disease treatment. There are many ways to achieve enhanced catalytic efficiency using semiconductors, such as precious metal encapsulation or loading, heterojunction construction, and heteroatom doping. Tin sulfide is a semiconductor and is mainly used in laboratory research and development / experiments. It is currently very active in the market and is widely used in fields such as photocatalysis, energy storage, and photodetection. However, its catalytic efficiency is limited by the rapid recombination of photogenerated electron-hole pairs and limited light absorption.

[0005] Recently, emerging research has adopted defect engineering approaches to improve the separation efficiency of photogenerated charge carriers for better photocatalytic performance. However, most photocatalytic reagents suffer from limited performance, high photoacoustic electron-hole pair recombination efficiency, and difficulty in controlling their morphology and size (such as uneven catalyst morphology and large size), which limits their application in catalysis, energy storage, and biomedicine. Summary of the Invention

[0006] The present invention aims to solve the problems of existing metal sulfide nanoparticles, such as high electron-hole pair binding efficiency, poor light response and catalytic performance, uneven catalyst morphology and large size, and further provide a method for preparing defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres.

[0007] A method for preparing defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres is carried out according to the following steps:

[0008] 1. Dissolve polyvinyl pyrrolidone in deionized water and stir to obtain a polyvinyl pyrrolidone solution;

[0009] 2. Add cuprous chloride solution, sodium hydroxide solution and ammonia water to the polyvinyl pyrrolidone solution in sequence and stir to obtain a light yellow copper oxide suspension;

[0010] 3. Adding the sodium sulfide solution dropwise to the light yellow copper oxide suspension to obtain a mixed solution A, heating the mixed solution A to 60°C to 65°C, and reacting at 60°C to 65°C for 1.5h to 2.5h. After the reaction is completed, naturally cool to room temperature, collect by centrifugation, wash and dry to obtain hollow mesoporous copper sulfide nanospheres;

[0011] 4. Dissolve tin tetrachloride and thiourea in deionized water and stir, then add hollow mesoporous copper sulfide nanospheres to obtain a mixed solution B, heat the mixed solution B to 180°C ~ 185°C, and react at a temperature of 180°C ~ 185°C for 19.5h ~ 20.5h. After the reaction is completed, naturally cool to room temperature, collect by centrifugation, wash and dry to obtain defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres.

[0012] The beneficial effects of the present invention are:

[0013] ①. The present invention prepares a kind of hollow mesoporous copper-doped tin sulfide nanospheres with controllable morphology and size, effective separation of electron-hole pairs, and defect engineering. Steady-state kinetic analysis confirms that they have good catalytic performance, with a Michaelis constant and a maximum reaction rate of 104.82mM and 2.94×10 -7 Ms -1 The specific activity value of defect-engineered copper-doped tin sulfide is 0.64U / mg.

[0014] ② Using template and ion exchange method, the prepared hollow mesoporous copper sulfide was used as template, tin tetrachloride as tin source, thiourea as sulfur source, and deionized water as solvent to react under high temperature and high pressure to generate defect-engineered hollow mesoporous copper-doped tin disulfide nanospheres. The prepared Cu-SnS 2-x The nanospheres are hollow mesoporous structures with an average size of about 300 nm and are uniform in size.

[0015] ③. Density functional theory calculations revealed that structural changes occur after copper substitution, which reduces the formation energy of sulfur vacancies (-0.52 eV). A special tin-sulfur-copper arrangement is established on the particle surface, which makes it easier to form sulfur vacancies and the electron density distribution in copper-doped tin sulfide is uneven.

[0016] ④. The sulfur vacancies induced by copper doping can improve the separation efficiency of photogenerated carriers, making the hollow mesoporous copper-doped tin sulfide have a wider light response range. It can be used as a photocatalytic material for the degradation of pollutants and a photothermal agent for photothermal treatment of diseases.

[0017] Therefore, the defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres of the present invention have a simple preparation method, good water solubility, photoresponse and catalytic performance, and have the characteristics of efficient separation of electron-hole pairs.

[0018] Figures in the specification

[0019] Figure 1 Schematic diagram of the preparation process of defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres in Example 1;

[0020] Figure 2 SnS2 nanoparticles prepared for comparison experiment and Cu-SnS prepared in Example 1 2-x X-ray diffraction spectrum of the nanospheres, a is the overall spectrum, b and c are the local enlarged views of a;

[0021] Figure 3 SnS2 nanoparticles prepared for comparison, CuS prepared in step 3 of Example 1, and Cu-SnS prepared in Example 1 2-x TEM imaging of nanospheres;

[0022] Figure 4 Cu-SnS prepared in Example 1 2-x Elemental mapping of nanospheres;

[0023] Figure 5 SnS2 nanoparticles prepared for comparison experiment and Cu-SnS prepared in Example 1 2-x X-ray photoelectron spectrum of nanospheres;

[0024] Figure 6 SnS2 nanoparticles prepared for comparison experiment and Cu-SnS prepared in Example 1 2-x UV-visible diffuse reflection absorption and energy band gap spectra of nanospheres, a is UV-visible diffuse reflection absorption graph, b is energy band gap spectrum, 1 is SnS2 nanoparticles, 2 is Cu-SnS 2-x Nanospheres;

[0025] Figure 7 SnS2 nanoparticles prepared by comparative experiment and Cu-SnS prepared by Example 1 2-x UV-visible absorption spectra and molar extinction coefficients of aqueous solutions of different concentrations for the preparation of nanospheres; a-1 is the UV-visible absorption spectrum of SnS2 nanoparticle solution, 1 is 15 μg / mL, 2 is 30 μg / mL, 3 is 60 μg / mL, 4 is 125 μg / mL, 5 is 250 μg / mL; b-1 is the molar extinction coefficient of SnS2 nanoparticle solution; a-2 is the molar extinction coefficient of Cu-SnS 2-x UV-visible absorption spectra of nanosphere solutions, 1 is 12.5 μg / mL, 2 is 25 μg / mL, 3 is 50 μg / mL, 4 is 100 μg / mL, 5 is 200 μg / mL; b-1 is Cu-SnS 2-x Molar extinction coefficient plot of nanosphere solution;

[0026] Figure 8 SnS2 nanoparticles prepared for comparison experiment and Cu-SnS prepared in Example 1 2-x High-resolution X-ray photoelectron spectroscopy of copper and sulfur ions in nanospheres;

[0027] Figure 9 The Cu-SnS prepared in Example 1 2-x Photothermal temperature change curves of nanospheres prepared into aqueous solutions with different concentrations, 1 is water, 2 is 25 μg / mL, 3 is 50 μg / mL, 4 is 100 μg / mL, and 5 is 200 μg / mL;

[0028] Figure 10 Cu-SnS prepared in Example 1 2-x Schematic diagram of the catalytic performance of nanospheres;

[0029] Figure 11 Cu-SnS prepared in Example 1 2-x UV-visible absorption spectra of 3,3',5,5'-tetramethylbenzidine and o-phenylenediamine catalyzed by nanospheres. 1 is blank, 2 is Cu-SnS 2-x Nanospheres, 3 for Cu-SnS 2-x Nanospheres + hydrogen peroxide, 4 is Cu-SnS 2-x Nanospheres + hydrogen peroxide + laser irradiation, a is catalytic 3,3',5,5'-tetramethylbenzidine, b is catalytic o-phenylenediamine;

[0030] Figure 12 Cu-SnS prepared in Example 1 2-x Catalytic kinetic performance of nanospheres, a is Cu-SnS under different concentrations of hydrogen peroxide 2-x Michaelis-Menten equation of nanosphere catalysis, b is Cu-SnS under different concentrations of hydrogen peroxide2-x Lambert-Beer law fitting curve of nanosphere catalysis, c is Cu-SnS with different masses 2-x Linear curves of absorbance of mixed solution of nanospheres and 3,3',5,5'-tetramethylbenzidine and different reaction times, 1 is 0.01 mg, 2 is 0.02 mg, 3 is 0.025 mg, 4 is 0.03 mg, 5 is 0.035 mg, d is Cu-SnS 2-x Fitting curve of catalytic activity of nanospheres;

[0031] Figure 13 Cu-SnS prepared in Example 1 2-x Schematic diagram of the evolution of sulfur vacancies in nanospheres;

[0032] Figure 14 SnS2 nanoparticles and Cu-SnS2 sulfur vacancy formation energy prepared in Example 1;

[0033] Figure 15 SnS2 nanoparticles prepared in Example 1 and Cu-SnS prepared in Example 1 2-x Optimized structure diagram of nanospheres;

[0034] Figure 16 SnS2 nanoparticles prepared in Example 1 and Cu-SnS prepared in Example 1 2-x Electron density distribution of the nanosphere. DETAILED DESCRIPTION

[0035] Specific embodiment 1: This embodiment is a method for preparing defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres, which is carried out according to the following steps:

[0036] 1. Dissolve polyvinyl pyrrolidone in deionized water and stir to obtain a polyvinyl pyrrolidone solution;

[0037] 2. Add cuprous chloride solution, sodium hydroxide solution and ammonia water to the polyvinyl pyrrolidone solution in sequence and stir to obtain a light yellow copper oxide suspension;

[0038] 3. Adding the sodium sulfide solution dropwise to the light yellow copper oxide suspension to obtain a mixed solution A, heating the mixed solution A to 60°C to 65°C, and reacting at 60°C to 65°C for 1.5h to 2.5h. After the reaction is completed, naturally cool to room temperature, collect by centrifugation, wash and dry to obtain hollow mesoporous copper sulfide nanospheres;

[0039] 4. Dissolve tin tetrachloride and thiourea in deionized water and stir, then add hollow mesoporous copper sulfide nanospheres to obtain a mixed solution B, heat the mixed solution B to 180°C ~ 185°C, and react at a temperature of 180°C ~ 185°C for 19.5h ~ 20.5h. After the reaction is completed, naturally cool to room temperature, collect by centrifugation, wash and dry to obtain defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres.

[0040] The defect-engineered hollow mesoporous copper-doped tin disulfide nanospheres prepared in this embodiment have the chemical formula: Cu-SnS 2-x .

[0041] The beneficial effects of this embodiment are:

[0042] ① In this embodiment, a kind of hollow mesoporous copper-doped tin sulfide nanospheres with controllable morphology and size, effective separation of electron-hole pairs, and defect engineering were prepared. Steady-state kinetic analysis confirmed that they had good catalytic performance, with a Michaelis constant and a maximum reaction rate of 104.82 mM and 2.94×10 -7 Ms -1 The specific activity value of defect-engineered copper-doped tin sulfide is 0.64U / mg.

[0043] ② Using template and ion exchange method, the prepared hollow mesoporous copper sulfide was used as template, tin tetrachloride as tin source, thiourea as sulfur source, and deionized water as solvent to react under high temperature and high pressure to generate defect-engineered hollow mesoporous copper-doped tin disulfide nanospheres. The prepared Cu-SnS 2-x The nanospheres are hollow mesoporous structures with an average size of about 300 nm and are uniform in size.

[0044] ③. Density functional theory calculations revealed that structural changes occur after copper substitution, which reduces the formation energy of sulfur vacancies (-0.52 eV). A special tin-sulfur-copper arrangement is established on the particle surface, which makes it easier to form sulfur vacancies and the electron density distribution in copper-doped tin sulfide is uneven.

[0045] ④. The sulfur vacancies induced by copper doping can improve the separation efficiency of photogenerated carriers, making the hollow mesoporous copper-doped tin sulfide have a wider light response range. It can be used as a photocatalytic material for the degradation of pollutants and a photothermal agent for photothermal treatment of diseases.

[0046] Therefore, the preparation method of the defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres in this embodiment is simple, water-soluble, has good photoresponse and catalytic performance, and has the characteristics of efficient separation of electron-hole pairs.

[0047] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the concentration of the polyvinyl pyrrolidone solution in step 1 is 4 mg / mL to 4.5 mg / mL. Other aspects are the same as those of specific embodiment 1.

[0048] Specific embodiment 3: This embodiment differs from either specific embodiment 1 or 2 in that: in step 1, polyvinyl pyrrolidone is dissolved in deionized water and stirred at a speed of 500 rpm to 600 rpm for 5 to 10 minutes to obtain a polyvinyl pyrrolidone solution. Other steps are the same as those of specific embodiment 1 or 2.

[0049] Specific embodiment 4: This embodiment differs from Specific embodiments 1 to 3 in that the concentration of the cuprous chloride solution in step 2 is 85 mg / mL to 90 mg / mL; the pH of the sodium hydroxide solution in step 2 is 8.5 to 9.5; and the mass percentage of the ammonia water in step 2 is 45% to 50%. Other aspects are the same as Specific embodiments 1 to 3.

[0050] Specific embodiment 5: This embodiment differs from Specific embodiments 1 to 4 in that: the mass ratio of polyvinyl pyrrolidone in the polyvinyl pyrrolidone solution to cuprous chloride in the cuprous chloride solution in step 2 is (0.17-0.18):1; the mass ratio of sodium hydroxide in the sodium hydroxide solution to cuprous chloride in the cuprous chloride solution in step 2 is (0.002-0.003):1; and the volume ratio of ammonia water to cuprous chloride solution in step 2 is (0.2-0.25):1. Other aspects are the same as Specific embodiments 1 to 4.

[0051] Specific embodiment 6: This embodiment differs from Specific embodiments 1 to 5 in that in step 2, the cuprous chloride solution, sodium hydroxide solution, and aqueous ammonia are sequentially added to the polyvinylpyrrolidone solution at a dropping rate of 30 to 35 drops / minute, and stirred at a rotation speed of 500 to 600 rpm for 5 to 10 minutes to obtain a light yellow copper oxide suspension. Other steps are the same as Specific embodiments 1 to 5.

[0052] Specific embodiment 7: This embodiment differs from Specific embodiments 1 to 6 in that the concentration of the sodium sulfide solution in step 3 is 300 mg / mL to 350 mg / mL; and the volume ratio of the sodium sulfide solution to the light yellow copper oxide suspension in step 3 is 1:(120-125). Other aspects are the same as Specific embodiments 1 to 6.

[0053] Specific embodiment 8: This embodiment differs from Specific embodiments 1 to 7 in that: in step 3, mixed solution A is heated to 60°C to 65°C at a heating rate of 2°C / min to 3°C / min, and the reaction is carried out at 60°C to 65°C for 1.5 to 2.5 hours; the centrifugal collection described in steps 3 and 4 is specifically centrifuged at a speed of 4000 rpm to 5000 rpm for 5 to 7 minutes; and the washing described in steps 3 and 4 is repeated 3 to 4 times with deionized water. Other steps are the same as Specific embodiments 1 to 7.

[0054] Specific embodiment 9: This embodiment differs from Specific embodiments 1 to 8 in that the concentration of tin tetrachloride in the mixed solution B described in step 4 is 0.17 mg / mL to 0.18 mg / mL, the concentration of thiourea is 0.1 mg / mL to 0.15 mg / mL, and the concentration of hollow mesoporous copper sulfide nanospheres is 0.06 mg / mL to 0.07 mg / mL. Other embodiments are the same as Specific embodiments 1 to 8.

[0055] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that in step 4, the mixed solution B is heated to 180°C to 185°C at a heating rate of 2°C / min to 3°C / min, and the reaction is carried out at 180°C to 185°C for 19.5 hours to 20.5 hours. Other steps are the same as specific embodiments 1 to 9.

[0056] The following examples are used to verify the beneficial effects of the present invention:

[0057] Example 1, combined with Figure 1 Specific instructions:

[0058] A method for preparing defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres is carried out according to the following steps:

[0059] 1. Dissolve polyvinyl pyrrolidone in deionized water and stir at 500 rpm for 10 minutes to obtain a polyvinyl pyrrolidone solution;

[0060] The concentration of the polyvinyl pyrrolidone solution is 4 mg / mL;

[0061] 2. Add the cuprous chloride solution, sodium hydroxide solution, and aqueous ammonia to the polyvinylpyrrolidone solution in sequence at a drop rate of 30 drops / minute, and stir at a speed of 500 rpm for 10 minutes to obtain a light yellow copper oxide suspension;

[0062] The concentration of the cuprous chloride solution is 85 mg / mL; the pH of the sodium hydroxide solution is 9; and the mass percentage of the ammonia water is 50%.

[0063] The mass ratio of polyvinyl pyrrolidone in the polyvinyl pyrrolidone solution to cuprous chloride in the cuprous chloride solution is 0.17:1; the mass ratio of sodium hydroxide in the sodium hydroxide solution to cuprous chloride in the cuprous chloride solution is 0.002:1; and the volume ratio of ammonia water to cuprous chloride solution is 0.2:1.

[0064] 3. Adding sodium sulfide solution dropwise to the light yellow copper oxide suspension to obtain mixed solution A, heating the mixed solution A to 60°C at a heating rate of 2°C / min, and reacting at 60°C for 2 hours. After the reaction is completed, the mixture is naturally cooled to room temperature, collected by centrifugation, washed and dried to obtain hollow mesoporous copper sulfide nanospheres (CuS);

[0065] The concentration of the sodium sulfide solution is 300 mg / mL; the volume ratio of the sodium sulfide solution to the light yellow copper oxide suspension is 1:125;

[0066] Fourth, tin tetrachloride and thiourea were dissolved in deionized water and stirred, and then hollow mesoporous copper sulfide nanospheres were added to obtain a mixed solution B. The mixed solution B was heated to 180°C at a heating rate of 2°C / min, and reacted at 180°C for 20 hours. After the reaction was completed, it was naturally cooled to room temperature, collected by centrifugation, washed and dried to obtain defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres (Cu-SnS 2-x nanospheres);

[0067] In the mixed solution B, the concentration of tin tetrachloride is 0.17 mg / mL, the concentration of thiourea is 0.1 mg / mL, and the concentration of hollow mesoporous copper sulfide nanospheres is 0.06 mg / mL.

[0068] The centrifugal collection in steps 3 and 4 is performed at a speed of 5000 rpm for 5 minutes. The washing in steps 3 and 4 is repeated three times with deionized water. The drying in steps 3 and 4 is performed at a temperature of 60° C. under vacuum for 3 hours.

[0069] Comparative Experiment: This comparative experiment differs from Example 1 in that the addition of hollow mesoporous copper sulfide nanospheres is omitted in step 4; tin disulfide nanoparticles (SnS2 nanoparticles) are obtained in step 4. Other aspects are the same as Example 1.

[0070] Figure 2 SnS2 nanoparticles prepared for comparison experiment and Cu-SnS prepared in Example 1 2-x X-ray diffraction spectrum of nanospheres, a is the overall spectrum, b and c are the local enlarged views of a; it can be seen from the figure that in Cu-SnS 2-xThe characteristic diffraction peak of copper sulfide was not observed in the X-ray diffraction spectrum of the nanospheres. 2-x The (100), (101), (110), and (111) crystal planes in the nanospheres shift toward low angles, and the diffraction peaks of the (002) and (103) crystal planes weaken or even disappear, indicating that copper doping leads to lattice expansion and increased spacing. The increased lattice spacing is due to the generation of sulfur vacancies in tin sulfide due to copper doping.

[0071] Figure 3 SnS2 nanoparticles prepared for comparison, CuS prepared in step 3 of Example 1, and Cu-SnS prepared in Example 1 2-x TEM imaging of nanospheres; Figure 4 Cu-SnS prepared in Example 1 2-x Element mapping of nanospheres; As can be seen from the figure, the prepared Cu-SnS 2-x The nanospheres are hollow mesoporous structures with an average size of about 300 nm and uniform size. Elements such as Cu, Sn and S can be seen evenly distributed in the nanospheres, indicating the successful preparation of hollow mesoporous sulfur vacancy copper-doped tin disulfide nanospheres.

[0072] Figure 5 SnS2 nanoparticles prepared for comparison experiment and Cu-SnS prepared in Example 1 2-x X-ray photoelectron spectrum of nanospheres; As can be seen from the figure, the prepared SnS2 nanoparticles and Cu-SnS 2-x Nanospheres are mainly composed of Sn and S elements, Cu-SnS 2-x The characteristic signal peak of Cu appears in the X-ray photoelectron spectrum of the nanospheres.

[0073] Figure 6 SnS2 nanoparticles prepared for comparison experiment and Cu-SnS prepared in Example 1 2-x UV-visible diffuse reflection absorption and energy band gap spectra of nanospheres, a is UV-visible diffuse reflection absorption graph, b is energy band gap spectrum, 1 is SnS2 nanoparticles, 2 is Cu-SnS 2-x Nanospheres; As can be seen from the figure, compared with SnS2 nanoparticles, Cu-SnS 2-x Due to the doping of copper ions and the production of sulfur vacancies, the Cu-SnS nanospheres 2-x The absorption peak of the nanospheres showed a red shift and a significant enhancement. 0.5 The relationship between SnS2 nanoparticles and Cu-SnS 2-x The band gap energies of the nanospheres are 2.30eV and 2.26eV, respectively. This confirms that Cu-SnS with sulfur vacancies was successfully prepared by copper doping. 2-xNanospheres with reduced band gap facilitate electron-hole separation.

[0074] Figure 7 SnS2 nanoparticles prepared by comparative experiment and Cu-SnS prepared by Example 1 2-x UV-visible absorption spectra and molar extinction coefficients of aqueous solutions of different concentrations for the preparation of nanospheres; a-1 is the UV-visible absorption spectrum of SnS2 nanoparticle solution, 1 is 15 μg / mL, 2 is 30 μg / mL, 3 is 60 μg / mL, 4 is 125 μg / mL, 5 is 250 μg / mL; b-1 is the molar extinction coefficient of SnS2 nanoparticle solution; a-2 is the molar extinction coefficient of Cu-SnS 2-x UV-visible absorption spectra of nanosphere solutions, 1 is 12.5 μg / mL, 2 is 25 μg / mL, 3 is 50 μg / mL, 4 is 100 μg / mL, 5 is 200 μg / mL; b-1 is Cu-SnS 2-x Molar extinction coefficient diagram of nanosphere solution; As can be seen from the figure, Cu-SnS 2-x The nanospheres have obvious absorption in the near-infrared region (700-900nm), and their absorption intensity of near-infrared light is higher than that of SnS2 nanoparticles. As the sample concentration increases, the absorbance increases significantly, which shows that they have a wide light response range. SnS2 nanoparticles and Cu-SnS 2-x The molar absorption coefficients of the nanospheres at 808 nm are 7.56 L / (g·cm) and 7.26 L / (g·cm), respectively. 2-x Nanospheres can be used as photothermal materials for photothermal therapy of diseases.

[0075] Figure 8 SnS2 nanoparticles prepared for comparison experiment and Cu-SnS prepared in Example 1 2-x High-resolution X-ray photoelectron spectra of copper ions and sulfur ions in nanospheres; As can be seen from the figure, no characteristic signal peak of copper ions was detected in the high-resolution X-ray photoelectron spectra of SnS2 nanoparticles, but for Cu-SnS 2-x Nanospheres, the signal peaks detected at the binding energy of 951.7eV and 931.9eV are derived from the 2p 1 / 2 and 2p 3 / 2 Compared with SnS2 nanoparticles, Cu-SnS 2-x The splitting peaks of sulfur ions in the nanospheres shifted toward lower binding energy and were located at 162.4 eV and 161.3 eV, respectively.

[0076] Figure 9 The Cu-SnS prepared in Example 1 2-xThe photothermal temperature change curves of the nanospheres prepared into aqueous solutions with different concentrations: 1 is water, 2 is 25 μg / mL, 3 is 50 μg / mL, 4 is 100 μg / mL, and 5 is 200 μg / mL. 2-x The temperature change curve of the nanosphere solution is concentration-dependent. When the laser is irradiated (wavelength 808 nm, power density 0.5 W / cm 2 ) and after 5 min of laser irradiation, Cu-SnS 2-x The temperature of the nanosphere aqueous solution (200 μg / mL) showed an obvious upward trend (ΔT≈27.5°C). Under the same treatment conditions, the temperature of the pure aqueous solution only increased by 2°C, indicating that Cu-SnS 2-x The nanospheres possess good light-to-heat conversion capability due to copper doping and the generation of sulfur vacancies.

[0077] Detection of Cu-SnS using 3,3',5,5'-tetramethylbenzidine and o-phenylenediamine 2-x The catalytic performance of the nanospheres was measured by measuring the absorbance values ​​of 3,3',5,5'-tetramethylbenzidine and o-phenylenediamine at 652 nm and 492 nm, respectively;

[0078] Experimental group 1: 0.6 mg of Cu-SnS prepared in Example 1 was added 2-x Nanospheres, 2.8 mL of water and 3,3',5,5'-tetramethylbenzidine were mixed to obtain a mixed solution 1-1, wherein the concentration of 3,3',5,5'-tetramethylbenzidine in the mixed solution 1-1 was 0.4 mM; or 0.6 mg of the Cu-SnS prepared in Example 1 was added. 2-x The nanospheres, 2.8 mL of water and o-phenylenediamine were mixed to obtain a mixed solution 1-2, wherein the concentration of o-phenylenediamine in the mixed solution 1-2 was 0.2 mM.

[0079] Experimental Group 2: 0.6 mg of Cu-SnS prepared in Example 1 was added 2-x Nanospheres, 2.6 mL of water and 3,3',5,5'-tetramethylbenzidine were mixed, and then hydrogen peroxide was added to obtain a mixed solution 2-1. The concentration of 3,3',5,5'-tetramethylbenzidine in the mixed solution 2-1 was 0.4 mM and the concentration of hydrogen peroxide was 60 mM; or 0.6 mg of Cu-SnS prepared in Example 1 was added. 2-x The nanospheres, 2.6 mL of water and o-phenylenediamine were mixed, and then hydrogen peroxide was added to obtain a mixed solution 2-2. The concentration of o-phenylenediamine in the mixed solution 2-2 was 0.2 mM, and the concentration of hydrogen peroxide was 60 mM.

[0080] Experimental group 3: using near-infrared laser (wavelength 808nm, power 0.5W cm -2 ) Mixed solution 2-1 and mixed solution 2-2 were irradiated for 5 minutes.

[0081] Figure 10 Cu-SnS prepared in Example 1 2-x Schematic diagram of the catalytic performance of nanospheres; Figure 11 Cu-SnS prepared in Example 1 2-x UV-visible absorption spectra of 3,3',5,5'-tetramethylbenzidine and o-phenylenediamine catalyzed by nanospheres. 1 is blank, 2 is Cu-SnS 2-x Nanospheres, 3 for Cu-SnS 2-x Nanospheres + hydrogen peroxide, 4 is Cu-SnS 2-x Nanospheres + hydrogen peroxide + laser irradiation, a is catalytic 3,3',5,5'-tetramethylbenzidine, b is catalytic o-phenylenediamine; As can be seen from the figure, Cu-SnS 2-x The nanospheres showed obvious catalytic performance for 3,3',5,5'-tetramethylbenzidine, and the absorbance of the solution reached a maximum at 652nm, and the absorbance intensity further increased at high temperature. Similar results were obtained using o-phenylenediamine as a detection agent, indicating that the unique advantages of abundant sulfur vacancies and copper doping make Cu-SnS 2-x Nanospheres have good catalytic activity, and heat can enhance the 2-x Catalytic properties of nanospheres.

[0082] The Cu-SnS prepared in Example 1 was detected using 3,3',5,5'-tetramethylbenzidine. 2-x Catalytic kinetic performance of nanospheres. 0.6 mg of Cu-SnS prepared in Example 1 was added 2-x Nanospheres, 2.6 mL of water and 3,3',5,5'-tetramethylbenzidine were mixed, and then hydrogen peroxide was added to obtain a mixed solution. The concentration of 3,3',5,5'-tetramethylbenzidine in the mixed solution was 6 mg / mL, and the concentrations of hydrogen peroxide were 8 mM, 30 mM, 60 mM, 120 mM and 180 mM, respectively. The absorbance of 3,3',5,5'-tetramethylbenzidine at 652 nm was measured under different concentrations of hydrogen peroxide, as shown in FIG. Figure 12 a and b; respectively 0.01mg, 0.02mg, 0.025mg, 0.03mg and 0.035mg of Cu-SnS prepared in Example 1 2-x Nanospheres, 2.6 mL of water and 3,3',5,5'-tetramethylbenzidine were mixed, and then hydrogen peroxide was added to obtain a mixed solution. The concentration of 3,3',5,5'-tetramethylbenzidine in the mixed solution was 6 mg / mL and the concentration of hydrogen peroxide was 100 mM. The Cu-SnS 2-x The absorbance value of the mixed solution of nanospheres and 3,3',5,5'-tetramethylbenzidine is as follows: Figure 12 middle c and d;

[0083] Figure 12 Cu-SnS prepared in Example 1 2-x Catalytic kinetic performance of nanospheres, a is Cu-SnS under different concentrations of hydrogen peroxide 2-x Michaelis-Menten equation of nanosphere catalysis, b is Cu-SnS under different concentrations of hydrogen peroxide 2-x Lambert-Beer law fitting curve of nanosphere catalysis, c is Cu-SnS with different masses 2-x Linear curves of absorbance of mixed solution of nanospheres and 3,3',5,5'-tetramethylbenzidine and different reaction times, 1 is 0.01 mg, 2 is 0.02 mg, 3 is 0.025 mg, 4 is 0.03 mg, 5 is 0.035 mg, d is Cu-SnS 2-x The catalytic activity fitting curve of nanospheres is shown in the figure. The steady-state kinetic analysis quantified the Cu-SnS 2-x The catalytic efficiency of the nanosphere composite sites at different hydrogen peroxide concentrations (8, 30, 60, 120, and 180 mM) was consistent with the Michaelis-Menten kinetics. The Michaelis-Menten constant and the maximum reaction rate were determined to be 104.82 mM and 2.94×10 -7 Ms -1 . The different mass Cu-SnS 2-x The absorbance curve of the mixed solution of nanospheres and 3,3',5,5'-tetramethylbenzidine versus reaction time shows that the absorbance value increases significantly with the increase of sample concentration. The catalytic activity value of defect-engineered copper-doped tin sulfide is calculated to be 0.64 U mg -1 .

[0084] Figure 13 Cu-SnS prepared in Example 1 2-x Schematic diagram of the evolution of sulfur vacancies in nanospheres; Figure 14 SnS2 nanoparticles and Cu-SnS2 sulfur vacancy formation energy prepared in Example 1; Figure 15 SnS2 nanoparticles prepared in Example 1 and Cu-SnS prepared in Example 1 2-x Optimized structure diagram of nanospheres; Figure 16 SnS2 nanoparticles prepared in Example 1 and Cu-SnS prepared in Example 1 2-x The electron density distribution of the nanospheres; As can be seen from the figure, the replacement of tin ions by copper ions will cause structural reconstruction and the generation of sulfur vacancies, establishing a special tin-sulfur-copper arrangement on the surface. 硫空位 =E(Cu-SnS 2-x)+E(sulfur)-E(Cu-SnS2), calculate the generation energy of sulfur vacancies, where E represents the generation energy. 2-x The structure of the nanospheres was optimized and adjusted to obtain the total energy of the perfect crystal and calculate the energy of sulfur atoms in sulfur. Compared with the formation energy of SnS2 (1.76eV), the formation energy of sulfur vacancies was significantly reduced to -0.52eV after copper doping, indicating that sulfur vacancies are easier to produce after copper ion doping. The model in the figure confirms that SnS2, SnS 2-x , Cu-SnS2 and Cu-SnS 2-x The Bader analysis shows that the introduction of Cu and the resulting Sv lead to an uneven charge distribution.

Claims

1. A method for preparing defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres, characterized in that It is carried out in the following steps:

1. Dissolve polyvinyl pyrrolidone in deionized water and stir to obtain a polyvinyl pyrrolidone solution; The concentration of the polyvinyl pyrrolidone solution is 4 mg / mL to 4.5 mg / mL; 2. Add the cuprous chloride solution, sodium hydroxide solution, and aqueous ammonia to the polyvinylpyrrolidone solution in sequence at a dropping rate of 30 to 35 drops per minute, and stir for 5 to 10 minutes at a rotation speed of 500 to 600 rpm to obtain a light yellow copper oxide suspension; The concentration of the cuprous chloride solution is 85 mg / mL to 90 mg / mL; the pH of the sodium hydroxide solution is 8.5 to 9.5; and the mass percentage of the ammonia water is 45% to 50%. The mass ratio of polyvinyl pyrrolidone in the polyvinyl pyrrolidone solution to cuprous chloride in the cuprous chloride solution is (0.17-0.18):1; the mass ratio of sodium hydroxide in the sodium hydroxide solution to cuprous chloride in the cuprous chloride solution is (0.002-0.003):1; the volume ratio of ammonia water to cuprous chloride solution is (0.2-0.25):1; 3. Add the sodium sulfide solution dropwise to the light yellow copper oxide suspension to obtain a mixed solution A, heat the mixed solution A to 60°C to 65°C at a heating rate of 2°C / min to 3°C / min, and react at 60°C to 65°C for 1.5h to 2.5h. After the reaction is completed, naturally cool to room temperature, collect by centrifugation, wash and dry to obtain hollow mesoporous copper sulfide nanospheres; The concentration of the sodium sulfide solution is 300 mg / mL to 350 mg / mL; the volume ratio of the sodium sulfide solution to the light yellow copper oxide suspension is 1:(120-125); 4. Dissolve tin tetrachloride and thiourea in deionized water and stir, then add hollow mesoporous copper sulfide nanospheres to obtain a mixed solution B, heat the mixed solution B to 180°C to 185°C at a heating rate of 2°C / min to 3°C / min, and react at 180°C to 185°C for 19.5h to 20.5h. After the reaction is completed, naturally cool to room temperature, collect by centrifugation, wash and dry to obtain defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres; The concentration of tin tetrachloride in the mixed solution B is 0.17 mg / mL to 0.18 mg / mL, the concentration of thiourea is 0.1 mg / mL to 0.15 mg / mL, and the concentration of hollow mesoporous copper sulfide nanospheres is 0.06 mg / mL to 0.07 mg / mL.

2. The method for preparing defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres according to claim 1, characterized in that In step 1, polyvinyl pyrrolidone is dissolved in deionized water and stirred at a rotation speed of 500 rpm to 600 rpm for 5 min to 10 min to obtain a polyvinyl pyrrolidone solution.

3. The method for preparing defect-engineered hollow mesoporous copper-doped tin sulfide nanospheres according to claim 1, characterized in that The centrifugal collection in step 3 and step 4 is specifically carried out at a rotation speed of 4000 rpm to 5000 rpm for 5 min to 7 min; the washing in step 3 and step 4 is repeated 3 to 4 times with deionized water.

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