Molybdenum disulfide nano material rich in sulfur defects as well as preparation method and application of molybdenum disulfide nano material

Abstract

The invention provides a molybdenum disulfide nano material rich in sulfur defects and a preparation method and application thereof, and belongs to the technical field of nano material preparation and sterilization. Starting from the properties of the molybdenum disulfide nano-material, sulfur defects with different concentrations are introduced to the surface of the nano-material through high-temperature calcination, and the molybdenum disulfide nano-material rich in sulfur defects is prepared; the molybdenum disulfide nano material rich in sulfur defects is in the shape of nano flower balls with the diameter of 200-300 nm, has the optimal photothermal conversion efficiency and high adsorbability under near-infrared light irradiation, and can efficiently inhibit the activity of escherichia coli and bacillus subtilis; the preparation method disclosed by the invention is simple in process, stable in reaction system, wide in reactant source and environment-friendly, shows a universal sterilization effect, is expected to introduce a new method in the field of sterilization of nano materials, provides a new technology and a new idea for design and preparation of functional nano materials, and has very good practicability.

Description

Technical Field

[0001] The invention belongs to the technical field of nano material preparation and sterilization, and specifically relates to a molybdenum disulfide nano material rich in sulfur defects and a preparation method and application thereof. Background Art

[0002] Bacterial infections are often found in food, water and medicines. They can easily induce a variety of diseases, such as sepsis, cholera, pneumonia, etc., and are considered to be one of the main causes of death in humans worldwide. The traditional antibacterial method is to use antibiotics to inhibit the growth of bacteria, thereby achieving the purpose of efficient sterilization. However, the excessive use of antibiotics in recent years has led to an increase in bacterial resistance and even the emergence of almost uncontrolled "super bacteria", posing a serious threat to human health and environmental protection. Therefore, the development of efficient, environmentally friendly, and side-effect-free non-antibiotic antibacterial materials has gradually become a research hotspot.

[0003] Molybdenum disulfide is a transition metal sulfide nanomaterial with excellent performance. It has a special energy band structure and shows broad application prospects in photocatalytic sterilization. When the radiation energy of light to molybdenum disulfide is greater than or equal to its band gap energy, the electrons in the valence band will jump to the conduction band to form conduction band electrons; at the same time, due to the migration of electrons in the valence band, holes will be generated at the corresponding positions, thereby generating highly active electron-hole pairs on the surface of molybdenum disulfide, and then generating a large amount of heat or active groups (such as hydroxyl radicals, superoxide radicals, etc.), destroying the integrity of the cell wall and cell membrane, and at the same time, the macromolecules inside the bacteria, such as proteins and genetic materials, will also be damaged, resulting in disordered bacterial growth and metabolism, thus achieving the purpose of killing bacteria. However, at present, molybdenum disulfide has the disadvantages of poor light response of the material itself, low utilization rate of near-infrared light, easy recombination of photogenerated charge-hole pairs on the surface of the material, and low photocatalytic activity of molybdenum disulfide, which makes it difficult to sterilize efficiently. Therefore, it is necessary to modify molybdenum disulfide and develop a molybdenum disulfide photocatalytic system with near-infrared light response to achieve efficient sterilization. Summary of the invention

[0004] In view of some deficiencies in the prior art, the present invention provides a molybdenum disulfide nanomaterial rich in sulfur defects and a preparation method and application thereof; starting from the properties of the molybdenum disulfide nanomaterial itself, the present invention introduces sulfur defects of different concentrations on the surface of the nanomaterial by high-temperature calcination to prepare a molybdenum disulfide nanomaterial rich in sulfur defects; the molybdenum disulfide nanomaterial rich in sulfur defects has a morphology of nanoflower balls with a diameter of 200-300nm, which has the best photothermal conversion efficiency and strong adsorption under near-infrared light irradiation, and can effectively inhibit the activity of Escherichia coli and Bacillus subtilis; the preparation method of the present invention has a simple process, a stable reaction system, a wide source of reactants and is environmentally friendly, and exhibits a universal bactericidal effect, and is expected to introduce a new method in the sterilization field of nanomaterials, provide new technologies and new ideas for the design and preparation of functional nanomaterials, and has good practicality.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical means:

[0006] The invention firstly provides a molybdenum disulfide nanomaterial rich in sulfur defects. The molybdenum disulfide nanomaterial rich in sulfur defects is a nano flower ball with a diameter of 200-300nm.

[0007] The present invention also provides a method for preparing the above-mentioned sulfur-defect-rich molybdenum disulfide nanomaterial, the preparation method comprising:

[0008] (1) Preparation of MoS2 Nanomaterials:

[0009] Fully dissolving ammonium molybdate in distilled water, then adding thiourea and hydroxy hydrochloric acid thereto and stirring until dissolved to obtain a mixed system, subjecting the mixed system to a hydrothermal reaction at a certain temperature, cooling to room temperature after the reaction is completed, centrifuging, washing, and drying to obtain a molybdenum disulfide nanomaterial;

[0010] (2) Preparation of MoS2 nanomaterials rich in sulfur defects:

[0011] Argon gas is introduced into the molybdenum disulfide nanomaterial, and then the material is calcined at 150-350° C. After the calcination is completed, the material is cooled to room temperature to obtain the molybdenum disulfide nanomaterial rich in sulfur defects.

[0012] Preferably, in step (1), the mass ratio of ammonium molybdate, thiourea and hydroxy hydrochloric acid is 0.2-0.3 g: 0.9-1.0 g: 0.2-0.3 g.

[0013] Preferably, in step (1), the hydrothermal reaction is carried out at 240° C. for 24 to 26 hours.

[0014] Preferably, in step (2), the calcination time is 2 to 3 hours.

[0015] The present invention also provides the use of the above-mentioned molybdenum disulfide nanomaterial rich in sulfur defects in photothermal sterilization.

[0016] Preferably, the bacteria include Escherichia coli and Bacillus subtilis.

[0017] Preferably, the photothermal sterilization comprises:

[0018] The bacterial liquid is dropped into physiological saline, mixed evenly with the aqueous solution of molybdenum disulfide nanomaterials rich in sulfur defects, and then incubated. After the incubation, it is sterilized by irradiation under near-infrared light.

[0019] Preferably, the ratio of the bacterial solution, physiological saline and sulfur-defect-rich molybdenum disulfide nanomaterial aqueous solution is 1 mL: 3.5 mL: 500 μL; wherein the concentration of the bacterial solution is 10 7 CFU / mL, and the concentration of sulfur-defective MoS2 nanomaterials was 500 μg / mL.

[0020] Preferably, the incubation condition is: incubation at 37° C. for 1 h.

[0021] Preferably, the near-infrared light is emitted by a single excitation light source laser at 808 nm, with an excitation power of 1.5 W / cm 2 , the illumination time is 10 minutes.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention starts from the properties of molybdenum disulfide nanomaterials themselves, that is, inhibiting the recombination of photogenerated charge-hole pairs, improving light responsiveness, and promoting the interaction between nanomaterials and bacteria. The present invention reasonably adjusts the calcination temperature, regulates the electronic structure of nanomaterials under the premise of avoiding excessive calcination temperature leading to collapse of molybdenum disulfide morphology, and then synthesizes molybdenum disulfide nanomaterials containing different sulfur defect concentrations, improves its light absorption in the near-infrared band, and promotes the effective separation of photogenerated electron-hole pairs. After 808nm laser irradiation, the nanomaterials rich in sulfur defects show the best photothermal conversion efficiency, produce local excessive heat, and because the surface defects of the nanomaterials provide more reactive sites, they have strong adsorption to both Escherichia coli and Bacillus subtilis, damage bacterial cell walls, inhibit energy supply, and damage the antioxidant system, greatly enhancing the photothermal sterilization efficiency of nanomaterials.

[0024] Compared with the prior art, this method improves the light absorption of molybdenum disulfide nanomaterials in the near-infrared band by regulating different concentrations of sulfur defects. After 808nm laser irradiation, its photothermal conversion efficiency is significantly enhanced, and it has the best sterilization efficiency. The preparation process is simple, and it is an efficient, safe, and green nano-fungicide. In addition, the laser irradiation power of the molybdenum disulfide nanomaterial rich in sulfur defects described in the present invention is low, the time is short, and the concentration of the material used for sterilization is low. By regulating the defect concentration, the purpose of 100% sterilization can be achieved, which plays a role in energy saving and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a scanning electron microscope (SEM) image of molybdenum disulfide nanomaterials with the same sulfur defect concentration; in the figure, a is MoS2-1 obtained at a calcination temperature of 150°C, b is MoS2-2 obtained at a calcination temperature of 250°C, c is MoS2-3 obtained at a calcination temperature of 350°C, and d is unmodified molybdenum disulfide.

[0026] Figure 2 This is the X-ray diffraction (XRD) pattern of MoS2 nanomaterials with different sulfur defect concentrations.

[0027] Figure 3 This is the electron paramagnetic resonance (EPR) spectrum of MoS2 nanomaterials with different sulfur defect concentrations.

[0028] Figure 4 This is the UV-visible-near-infrared absorption spectrum of molybdenum disulfide nanomaterials with different sulfur defect concentrations.

[0029] Figure 5 This is the light heating curve of molybdenum disulfide nanomaterials with different sulfur defect concentrations.

[0030] Figure 6 is the Escherichia coli inactivation rate of MoS2 nanomaterials with different sulfur defect concentrations.

[0031] Figure 7 is the inactivation rate of Bacillus subtilis by MoS2 nanomaterials with different sulfur defect concentrations. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0033] Example 1: Preparation of MoS2 Nanomaterials Rich in Sulfur Defects

[0034] (1) Preparation of MoS2 Nanomaterials:

[0035] 0.2648 g of ammonium molybdate was fully dissolved in 40 mL of distilled water until the solution system became clear, and then 0.9134 g of thiourea powder and 0.21 g of hydroxy hydrochloric acid powder were added thereto, and the reactants were vigorously stirred. After they were fully dissolved, the reactor was placed in a 240°C oven for continuous reaction for 24 hours. After the reaction was completed, the reactor was taken out and allowed to cool naturally to room temperature, and the reactants were transferred to a centrifuge tube, washed several times with anhydrous ethanol and distilled water, and then dried to obtain unmodified molybdenum disulfide nanomaterials.

[0036] (2) Preparation of MoS2 nanomaterials rich in sulfur defects:

[0037] The molybdenum disulfide nanomaterial was placed in a tubular furnace, argon gas was introduced stably, and the calcination temperature was adjusted to 150°C for 2 hours. After the temperature of the tubular furnace was naturally cooled to room temperature, a molybdenum disulfide nanomaterial with a low concentration of sulfur defects was obtained, which was recorded as MoS2-1.

[0038] Figure 1 a is a scanning electron microscope image of MoS2-1. It can be seen from the figure that MoS2-1 is a uniform nanoflower ball with a diameter of 200 to 300 nm.

[0039] Example 2: Preparation of MoS2 Nanomaterials Rich in Sulfur Defects

[0040] (1) Preparation of MoS2 Nanomaterials:

[0041] 0.2648 g of ammonium molybdate was fully dissolved in 40 mL of distilled water until the solution system became clear, and then 0.9134 g of thiourea powder and 0.21 g of hydroxy hydrochloric acid powder were added thereto, and the reactants were vigorously stirred. After they were fully dissolved, the reactor was placed in a 240°C oven and the reaction was continued for 24 hours. After the reaction was completed, the reactor was taken out and allowed to cool naturally to room temperature, and the reactants were transferred to a centrifuge tube, washed several times with anhydrous ethanol and distilled water, and then dried to obtain molybdenum disulfide nanomaterials.

[0042] (2) Preparation of MoS2 nanomaterials rich in sulfur defects:

[0043] The molybdenum disulfide nanomaterial was placed in a tubular furnace, argon gas was introduced stably, and the calcination temperature was adjusted to 250°C for 2 hours. After the temperature of the tubular furnace was naturally cooled to room temperature, a molybdenum disulfide nanomaterial with medium-concentration sulfur defects was obtained, which was recorded as MoS2-2.

[0044] Figure 1 b is a scanning electron microscope image of MoS2-2. It can be seen from the figure that MoS2-2 is a uniform nanoflower ball with a diameter of 200 to 300 nm.

[0045] Example 3: Preparation of MoS2 Nanomaterials Rich in Sulfur Defects

[0046] (1) Preparation of MoS2 Nanomaterials:

[0047] 0.2648 g of ammonium molybdate was fully dissolved in 40 mL of distilled water until the solution system became clear, and then 0.9134 g of thiourea powder and 0.21 g of hydroxy hydrochloric acid powder were added thereto, and the reactants were vigorously stirred. After they were fully dissolved, the reactor was placed in a 240°C oven and the reaction was continued for 24 hours. After the reaction was completed, the reactor was taken out and allowed to cool naturally to room temperature, and the reactants were transferred to a centrifuge tube, washed several times with anhydrous ethanol and distilled water, and then dried to obtain molybdenum disulfide nanomaterials.

[0048] (2) Preparation of MoS2 nanomaterials rich in sulfur defects:

[0049] The molybdenum disulfide nanomaterial was placed in a tubular furnace, argon gas was introduced stably, and the calcination temperature was adjusted to 350°C for 2 hours. After the temperature of the tubular furnace was naturally cooled to room temperature, a molybdenum disulfide nanomaterial with a high concentration of sulfur defects was obtained, which was recorded as MoS2-3.

[0050] Figure 2 This is the X-ray diffraction pattern (XRD) of molybdenum disulfide nanomaterials with different sulfur defect concentrations. It can be seen from the figure that the three defective nanomaterials have good crystallinity and do not show any impurity peaks.

[0051] Figure 3 This is the electron paramagnetic resonance spectrum (EPR) of molybdenum disulfide nanomaterials with different sulfur defect concentrations. It can be seen from the figure that with the increase of calcination temperature, the sulfur defect concentration on the surface of the three defective nanomaterials gradually increases.

[0052] Figure 4 This is the UV-Vis-NIR absorption spectrum of molybdenum disulfide nanomaterials with different sulfur defect concentrations. It can be seen from the figure that with the increase of calcination temperature, the absorbance of the three defective nanomaterials in the 808nm band gradually increases, indicating that the increase in sulfur defect concentration can significantly improve the near-infrared absorption performance of the material by improving the separation of photogenerated electron-hole pairs in the material.

[0053] Figure 5 This is a graph of the photothermal heating of MoS2 nanomaterials with different sulfur defect concentrations. As can be seen from the graph, as the calcination temperature increases, the photothermal heating of the three defective nanomaterials in the 808nm band gradually increases, indicating that the increase in sulfur defect concentration improves the photothermal conversion effect of the material by improving the near-infrared light responsiveness of the material, thereby increasing the temperature of the solution. After 10 minutes of photothermal treatment of the original MoS2, the temperature of the aqueous solution does not exceed 45°C, which is far from achieving the purpose of photothermal sterilization.

[0054] Embodiment 4:

[0055] This example uses a coated plate method to determine the bactericidal efficiency of the unmodified molybdenum disulfide and the molybdenum disulfide nanomaterials containing different concentrations of sulfur defects obtained in Examples 1 to 3, and the specific steps are as follows:

[0056] Take a single colony of Escherichia coli and Bacillus subtilis and place it in Luria-Bertani solid medium (tryptone, NaCl, yeast extract, water) and place it in a shaker to allow it to fully proliferate. The temperature is controlled at 37°C. When the density increases to 10 7 After the concentration of CFU / mL was measured, 1 mL of bacterial solution was dripped into 3.5 mL of normal saline, and then mixed thoroughly with 500 μL of 500 μg / mL nanomaterials. After incubation on a shaker for 1 hour, 1 mL of the mixture was irradiated under an 808 nm laser (1.5 W / cm 2 ) After 10 minutes, dilute with saline and take 100 μL to count on a plate, and place the agar plate in a 37 degree incubator overnight. The test results are as follows: Figure 6 and 7 shown.

[0057] Combination Figure 6 and 7 It can be seen that as the concentration of sulfur defects increases, the sterilization effect gradually increases, and the molybdenum disulfide nanomaterials with high concentrations of sulfur defects can inactivate 100% of Escherichia coli and Bacillus subtilis. The main mechanism is that as the concentration of sulfur defects increases, the separation of photogenerated electron-hole pairs can be effectively improved, and the light responsiveness of the material in the 808nm band is significantly improved. After laser irradiation, it shows a photothermal warming effect dependent on the concentration of sulfur defects, achieving the purpose of sterilization. Compared with the prior art, the laser irradiation power of the molybdenum disulfide nanomaterial rich in sulfur defects is lower, the time is less, and the concentration of the material used for sterilization is lower. By adjusting the defect concentration, the purpose of 100% sterilization can be achieved, which plays a role in energy conservation and emission reduction.

[0058] In summary, the sulfur-defective molybdenum disulfide nanomaterial described in the present invention has the best photothermal conversion efficiency and strong adsorption under near-infrared light irradiation, and can effectively inhibit the activity of Escherichia coli and Bacillus subtilis; the preparation method described in the present invention has a simple process, a stable reaction system, a wide source of reactants and is environmentally friendly, and exhibits a universal bactericidal effect. It is expected to introduce a new method in the field of sterilization of nanomaterials, provide new technologies and new ideas for the design and preparation of functional nanomaterials, and has good practicality.

[0059] The embodiments are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. A method for preparing a molybdenum disulfide nanomaterial rich in sulfur defects, characterized in that: The preparation method comprises: (1) Preparation of MoS2 Nanomaterials: Fully dissolving ammonium molybdate in distilled water, then adding thiourea and hydroxy hydrochloric acid thereto and stirring until dissolved to obtain a mixed system, subjecting the mixed system to a hydrothermal reaction at a certain temperature, cooling to room temperature after the reaction is completed, centrifuging, washing, and drying to obtain a molybdenum disulfide nanomaterial; (2) Preparation of MoS2 nanomaterials rich in sulfur defects: Argon gas is introduced into the molybdenum disulfide nanomaterial, and then the material is calcined at 150-350° C. After the calcination is completed, the material is cooled to room temperature to obtain the molybdenum disulfide nanomaterial rich in sulfur defects.

2. The method for preparing a sulfur-defect-rich molybdenum disulfide nanomaterial according to claim 1, characterized in that: In step (1), the mass ratio of ammonium molybdate, thiourea and hydroxy hydrochloric acid is 0.2-0.3 g: 0.9-1.0 g: 0.2-0.3 g.

3. The method for preparing the sulfur-defect-rich molybdenum disulfide nanomaterial according to claim 1, characterized in that: In step (1), the conditions of the hydrothermal reaction are: reacting at 240° C. for 24 to 26 hours.

4. The method for preparing a sulfur-defect-rich molybdenum disulfide nanomaterial according to claim 1, characterized in that: In step (2), the calcination time is 2 to 3 hours.

5. The sulfur-defective molybdenum disulfide nanomaterial prepared by the method according to any one of claims 1 to 4, characterized in that: The molybdenum disulfide nanomaterial rich in sulfur defects is a nano flower ball with a diameter of 200-300nm.

6. Use of the sulfur-defect-rich molybdenum disulfide nanomaterial according to claim 5 in photothermal sterilization.

7. The use according to claim 6, characterized in that: The bacteria include Escherichia coli and Bacillus subtilis.

8. The use according to claim 6, characterized in that: The photothermal sterilization comprises: The bacterial liquid is dropped into physiological saline, mixed evenly with the aqueous solution of molybdenum disulfide nanomaterials rich in sulfur defects, and then incubated. After the incubation, it is sterilized by irradiation under near-infrared light.

9. The use according to claim 8, characterized in that: The dosage ratio of the bacterial solution, physiological saline and sulfur-defect-rich molybdenum disulfide nanomaterial aqueous solution is 1 mL: 3.5 mL: 500 μL; wherein the concentration of the bacterial solution is 10 7 CFU / mL, and the concentration of sulfur-defective MoS2 nanomaterials was 500 μg / mL.

10. The use according to claim 8, characterized in that: The incubation conditions are: incubate at 37°C for 1 h; The near-infrared light is emitted by a single excitation light source laser at 808 nm, with an excitation power of 1.5 W / cm 2 , the illumination time is 10 minutes.

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