Ag monatomic-graphene antibacterial material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of antibacterial material preparation, and discloses an Ag single atom-graphene antibacterial material as well as a preparation method and application thereof, and the Ag single atom-graphene antibacterial material is prepared by embedding Ag single atoms into graphene crystal lattices which contain a large number of point vacancy defects and are complete in lamellar structure by adopting a simple and feasible dipping-roasting method. Ag is uniformly loaded on graphene in a monatomic high-density manner, and is fully exposed, so that the effective capacity is high, and viruses and bacteria can be better contacted and inhibited. Ag atoms are stably confined in graphene point vacancy defects, Ag still exists in the form of single atoms after the material is roasted in a nitrogen atmosphere at 500 DEG C, and the Ag single atoms are also very stable during high-pressure steam sterilization at 115 DEG C. The graphene Ag-loaded material has good compatibility with resin, polypropylene and other organic materials, can be compounded to prepare antibacterial resin or plastic, and can enhance the bonding strength. The preparation method is simple, the Ag atom utilization rate is high, the stability is good, the antibacterial effect is excellent, and the high application value is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of antibacterial material preparation, and relates to an Ag single atom-graphene antibacterial material and its preparation method and application, and specifically relates to a material in which metal single atoms such as silver are loaded on graphene and a preparation method of the material. Background Art

[0002] Silver-loaded materials, with their low toxicity and broad-spectrum antimicrobial properties, are widely used in medical materials for antibacterial and anti-infection applications, surface antimicrobial applications in kitchen and bathroom fixtures, antimicrobial applications in architectural coatings and daily chemical products, and antimicrobial applications in textiles such as fiber clothing. In the biomedical field, silver-loaded materials can be used not only to inhibit common pathogens but also to inhibit and kill multidrug-resistant bacteria. Their antibacterial, antiviral, and anticancer properties hold great promise for their application in this field. Silver-loaded composite materials, obtained by combining silver with organic materials, not only possess antibacterial and wound-healing properties but also exhibit excellent clinical and pharmacological biocompatibility. Nanosilver or inorganic silver-loaded materials can be incorporated into organic carriers such as resins and polypropylene to produce antimicrobial resins or plastics, which have a wide range of applications in medical materials and daily necessities. For example, in medical material research, silver-loaded zirconium phosphate can be added to resin powder to produce antimicrobial resin bases. Nanosilver particles combined with hydroxymethyl cellulose can be used to prepare composite antimicrobial materials with antibacterial, antifungal, and anticancer activities. Silver-loaded zeolites combined with polypropylene can produce antimicrobial plastics.

[0003] In order to enhance the performance of silver-loaded antibacterial materials, efforts should be made in the following aspects:

[0004] (1) Increase the effective capacity of silver loading. The higher the silver loading, the better the effect. Only the silver atoms exposed on the surface can play an antibacterial role, while the silver atoms wrapped inside the silver particles cannot play a role. The higher the ratio of silver atoms exposed on the surface to all silver atoms, the more effective the silver loading is. If silver exists in the form of a single atom, the silver loaded is 100% effective. However, in the silver-loaded materials currently developed, silver mainly exists in the form of nanoparticles, and the utilization rate is low.

[0005] (2) Improve the stability of silver loading. The silver component in many silver-loaded materials is not firmly bonded to the carrier surface. It is easy to fall off or aggregate during use by relying solely on physical forces. Therefore, it is necessary to improve the material and preparation process to increase the bonding strength of silver and demonstrate stability in certain acidic and alkaline environments and hot and cold environments.

[0006] (3) Enhance the compatibility of silver-loaded materials with organic materials. Silver-loaded materials are compounded with organic materials such as resins and polypropylene to prepare antibacterial resins or plastics for medical or food packaging. For example, in the preparation of antibacterial resin bases, it is necessary to enhance the bonding strength between the silver-loaded materials and the organic materials. Based on similar compatibility, carbon-based silver-loaded materials will have stronger bonding strength and compatibility with organic materials such as resins and polypropylene. However, the dispersion and stability of silver in carbon-based materials are not as good as those of inorganic materials. If silver can be stably loaded on carbon-based materials at the atomic level, then such silver-loaded materials compounded with organic materials will have both good antibacterial effects and material compatibility.

[0007] As one of the most promising materials of the 21st century, graphene, with its large surface area, wide two-dimensional structure, and excellent electrical conductivity, can be combined with single metal atoms to modulate the physicochemical properties of these metal components, such as active biocatalytic performance, acid and alkali resistance, hydrothermal resistance, and resistance to oxidative inactivation. Its excellent qualities have attracted attention in many fields, including significant potential for application in antibacterial materials. Currently, silver-loaded graphene materials used for antibacterial purposes primarily incorporate silver nanoparticles bound to graphene. However, to date, there have been no reports on the construction of silver single-atom-graphene antibacterial materials.

[0008] References

[0009] [1] Nie Huifang, Wang Yujie, Research progress of silver / graphene composite materials, New Chemical Materials, 2024, 52(2), 246; Feng Yiping, Zhang Yijian, Chen Guang, et al.

[0010] [2] Preparation and bactericidal properties of nanosilver / graphene gel, Laboratory Research and Exploration, 2021, 40(8): 1-4; Meng Bobo, Hu Shanshan, Chang Chaoran, Cao Yueping, Wang Zhiping

[0011] [3] Preparation and antibacterial study of graphene oxide nanosilver, Shandong Chemical Industry, 2024, 53, 32; Karthika Prasad, GS Lekshmi, Kola Ostrikov, et al, Synergic bactericidal effects of reduced graphene oxide and silver nanoparticles against Gram-positive and Gram-negative bacteria, Scientific Reports, 2017, 7, 1591; Jiang Zhu, Haitao Ni, Chunyan Hu, et al

[0012] [4]Rapid synthesis and characterization of silver-loaded grapheneoxide nanomaterials and their antibacterial applications, 2021,2,24; Jia Tang, Qian Chen, Ligeng Xu, et al,

[0013] [5]Graphene Oxide-Silver Nanocomposite As a Highly Effective Antibacterial Agent with Species-Specific Mechanisms,ACSAppl.Mater.Interfaces 2013,5,9,3867-3874; NMDat,DBThinh,LMHuong,et al,

[0014] [6]Facile synthesis and antibacterial activity of silvernanoparticles-modified graphene oxide hybrid material: the assessment, utilization, and anti-virus potentiality, Materials Today Chemistry, 2022, 23, 100738. Summary of the Invention

[0015] In order to overcome the shortcomings and deficiencies of the above-mentioned prior art, the present invention provides a method for preparing silver or other Ag single atom-graphene antibacterial material, specifically an antibacterial material with silver or other metal single atoms loaded on graphene, and the preparation method and application of the material.

[0016] The idea of the present invention is that the composition and structural characteristics of graphene materials and the metal loading method have an important influence on the loading capacity, dispersion state and stability of metal single atoms such as Ag. Usually, graphene materials with intact crystal structure cannot load and stabilize metal single atoms on a large scale. In order to achieve silver being highly dispersed and stably embedded in the graphene lattice at the atomic level, and significantly improving the effective capacity of loaded silver and the stability of silver single atoms, the present invention has made two technical improvements: first, by improving the Hummers method graphene preparation technology, that is, adding a slow etching step at room temperature, a hydrogen-rich graphene with a complete lamellar structure and a large number of point vacancy defects evenly distributed is synthesized. These point defects can induce the positioning of metal single atoms for loading, which is a key step in synthesizing single-atom-graphene materials with high loading and uniform distribution. Secondly, because the surface of the graphene material is relatively non-polar, if it is impregnated with a conventional salt solution, it is easy to cause uneven distribution or even inability to load. The present invention adjusts the impregnation liquid, uses ethanol to prepare the salt solution, and pretreats the graphene with ethanol vapor, which is compatible with the solubility of the salt and the wettability of the graphene material. Under the comprehensive effect of multiple aspects, a high single-atom loading and uniform distribution are achieved.

[0017] like Figure 1 As shown, the single-atom loading of Ag on graphene is large and the single-atom distribution is relatively uniform. In the antibacterial material prepared by the present invention, metals such as silver are uniformly and densely loaded on the graphene surface in the form of single atoms. If Ag atoms were physically attached to the graphene surface, Ag would aggregate and fall off during high-temperature treatment. The synthesized antibacterial material has undergone nitrogen-cured calcination at 500°C, indicating that Ag is stably confined in the graphene lattice. Therefore, it will not fall off during low-temperature steam treatment or solvent system, demonstrating high stability.

[0018] The advantages of using silver and other metal single atom-graphene materials to develop silver-loaded antibacterial nanomaterials are as follows:

[0019] (1) Silver is loaded in the form of single atoms, fully exposed, and has a high effective capacity. Figure 2 As shown, if silver is present in the form of 10-nanometer particles, less than 30% of the silver atoms are exposed on the surface. If silver is present in single-atom form, 100% of the silver atoms are exposed on the surface. Using the same amount of silver, distributed in single-atom form, silver atoms are more efficiently utilized and cover a larger area. The effective capacity of silver is crucial for contacting and inhibiting viruses and bacteria.

[0020] (2) Silver atoms are embedded in the graphene lattice defects, not simply physically adsorbed, and have good stability. Figure 3As shown, some silver-loaded materials have the loaded silver component physically attached to the material surface. During high-temperature calcination or hydrothermal environments, the silver component will migrate and become unstable. The Ag single atom of the present invention is embedded in the graphene lattice and chemically bonded to the graphene crystal grid, showing excellent stability in certain acidic and alkaline environments and in hot and cold environments.

[0021] (3) Graphene-loaded silver materials have good compatibility with organic materials. Antibacterial resins or plastics that can be prepared by compounding graphene-loaded silver materials with organic materials such as resins and polypropylene can enhance the bonding strength when used to prepare antibacterial resin bases. Silver is more easily dispersed and adhered to inorganic materials (such as zeolite molecular sieves, montmorillonite, etc.). However, these inorganic materials are not compatible with organic materials such as resins and polypropylene, and are easily unable to disperse or fall off, which has many disadvantages in the fields of medicine and food. Graphene itself is a carbon-based material, which is similarly compatible with organic materials such as resins and polypropylene, and has stronger bonding strength and compatibility.

[0022] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0023] A method for preparing a Ag single atom-graphene antibacterial material comprises the following steps: using graphene containing a large number of point vacancy defects as a carrier, and adopting an impregnation-calcination method to embed metal single atoms in the graphene lattice to obtain the Ag single atom-graphene antibacterial material;

[0024] The carrier of the material is graphene, which contains a large number of point vacancy defects and a complete layer structure; Ag is uniformly loaded on the graphene at a high density of single atoms;

[0025] The main metal component loaded by the material is Ag, and it may also contain one or more of Cu, Zn, Fe, Co, Ni, and Mo metal components;

[0026] The antibacterial agent is prepared by an impregnation-calcination method, and the specific steps are as follows:

[0027] (1) Preparation of graphene carriers containing a large number of point vacancy defects:

[0028] ① Low-temperature reaction: Take a clean beaker (2.5L), add 230mL of concentrated sulfuric acid and 5.0g of sodium nitrate, stir thoroughly in an ice bath, and when the temperature is less than 5°C, add 10.0g of graphite powder and stir evenly for 2.5h; then weigh 30.0g of potassium permanganate (KMnO4) and slowly add it to the mixture system. During the addition, control the system temperature not to exceed 20°C;

[0029] ②Medium-temperature reaction: Transfer the beaker from step ① to a 35°C constant-temperature water bath and continue heating and stirring for 2 hours;

[0030] ③ High temperature reaction: Take out the beaker and add 460mL of deionized water into it, stir evenly. At this time, the sulfuric acid dilution will release heat. Then put the beaker into a 110-120℃ oil bath (the temperature of the oil bath varies depending on the season). Continue heating and stirring. Start timing when the temperature of the mixture in the beaker reaches 95-100℃ (98℃ is preferred). Stop heating after 15 minutes and take the beaker out of the oil bath.

[0031] ④ Slow etching at room temperature: Add 1.4L of deionized water to a beaker, along with 25mL of 30% hydrogen peroxide (approximately 10mol / L). Stir vigorously for 1 hour. Then, let it stand and slowly etch at room temperature for 12 hours. After 12 hours, remove 1.0L of the supernatant and add 1.0L of deionized water. Add 1-10mL of 30% hydrogen peroxide (approximately 10mol / L). Stir for 1 hour, let it stand, and continue slowly etching at room temperature for 12 hours. Repeat this process 1-3 times.

[0032] ⑤ Washing: After the slow etching is completed, the graphene paste is washed by centrifugation with deionized water until it is neutral, or dialyzed to neutrality.

[0033] ⑥ Reduction Treatment: Disperse the prepared graphene paste in 1000 mL of deionized water and ultrasonicate for 30 minutes to a 1 mg / mL dispersion. Add 25 mL of 30% ammonia and 6 mL of 80% hydrazine hydrate. Reflux in a 95°C oil bath for 3 hours, then add 4 mL of 80% hydrazine hydrate and allow to react for 30 minutes. After the reaction, add 4% hydrochloric acid until the graphene floats. Filter and wash while hot. Freeze-dry to obtain hydrogen-rich graphene.

[0034] (2) Impregnation:

[0035] ① Preparation of salt solution: Take nitrate and dissolve it in a mixed solution of water and organic solvent to make a salt solution. The volume of the solution is just enough to be absorbed by the hydrogen-rich graphene carrier.

[0036] ② Weigh the graphene prepared in step (1), spread it on a watch glass, and place it on a holder in a container with ethanol liquid. Keep it sealed for 1 to 3 hours. The ethanol vapor will be adsorbed on the surface of the graphene, playing a wetting role.

[0037] ③ Add the wetted graphene to the salt solution and stir continuously with a glass rod to quickly bring the graphene into contact with the liquid. Then, place the sample at room temperature for 1 to 3 hours.

[0038] ④ Place the sample in a vacuum drying oven at 50°C for 12 h, then grind the sample into powder using an agate mortar;

[0039] (3) Calcination: The powdered sample prepared in step (2) was placed in a quartz tube, placed in a tube furnace, and heated from room temperature to 500°C at a temperature of 10°C / min under a nitrogen atmosphere. The sample was calcined at 500°C for 2 h. When the temperature dropped to room temperature, ventilation was stopped, and the sample was taken out and sealed for storage.

[0040] The total amount of salt prepared in step (2) is 0.1-4.0 mmol / g carrier, wherein the amount of Ag is 0.05-2.0 mmol / g carrier.

[0041] The organic solvent in the mixed solution of the dissolved salt is preferably ethanol, and can also be methanol, acetone, tetrahydrofuran, formic acid, acetic acid, and an organic solvent that has a certain mutual solubility with water and is volatile. The volume ratio of water to organic solvent is 1:0 to 0:1, preferably 8:2 to 5:5.

[0042] The present invention has the following advantages and effects compared to the prior art:

[0043] The present invention proposes a method for preparing silver single-atom-graphene antibacterial materials. By improving upon the Hummers method for graphene preparation, the method adds a slow etching step at room temperature to synthesize hydrogen-rich graphene with a complete lamellar structure and a large number of evenly distributed point vacancy defects. This allows for highly atomically dispersed silver on the graphene, fully exposed and providing a high effective capacity for better contact and inhibition of viruses and bacteria. Silver single atoms are embedded within the graphene lattice defects, rather than simply physically adsorbed, resulting in excellent stability. Silver components migrate and become unstable during high-temperature calcination or hydrothermal conditions. Graphene-loaded silver materials exhibit good compatibility with organic materials such as resins and polypropylene, and can be combined with antibacterial resins or plastics to enhance bonding strength. Furthermore, the silver single-atom-graphene antibacterial material is prepared using an impregnation-calcination method, which is simple and highly feasible. Chemically prepared graphene-loaded metal single atoms are rarely and unevenly distributed, making them unsuitable for loading metal single atoms.

[0044] Figures in the specification

[0045] Figure 1 This is a spherical aberration electron microscopy (HAADF-STEM) image of a Ag single atom-graphene composite antibacterial material prepared using self-synthesized graphene. The white bright spots are Ag single atoms, which shows that the Ag single atoms have a high density and are evenly dispersed.

[0046] Figure 2 Schematic diagram of the distribution of the same number of silver atoms, a is in the form of nanoparticle distribution, b is in the form of single atom distribution;

[0047] Figure 3This is a comparison diagram of the physical attachment of the silver component to the material surface and the chemical embedding of the silver component into the graphene lattice. a is a schematic diagram of the surface before the silver component is physically attached to the material, b is a schematic diagram of the surface after the silver component is physically attached to the material, c is a schematic diagram of the structure before the silver component is chemically embedded into the graphene lattice, and d is a schematic diagram of the structure after the silver component is chemically embedded into the graphene lattice.

[0048] Figure 4 This is a photo of the antibacterial effect of mixed culture in MHB medium;

[0049] Figure 5 This is a photograph of the limiting dilution plate count results. DETAILED DESCRIPTION

[0050] The present invention will be described in further detail below with reference to the examples, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can be purchased from chemical companies.

[0051] Example 1 Self-synthesized graphene loaded with Ag metal single atom-graphene antibacterial material

[0052] 1. Preparation of graphene carrier:

[0053] ① Low-temperature reaction: Take a clean beaker (2.5L), add 230mL of concentrated sulfuric acid and 5.0g of sodium nitrate, stir thoroughly in an ice bath, and when the temperature is less than 5°C, add 10.0g of graphite powder and stir evenly for 2.5h; then weigh 30.0g of potassium permanganate (KMnO4) and slowly add it to the mixture system. During the addition, control the system temperature not to exceed 20°C;

[0054] ②Medium-temperature reaction: Transfer the beaker from step ① to a 35°C constant-temperature water bath and continue heating and stirring for 2 hours;

[0055] ③ High temperature reaction: Take out the beaker and add 460mL of deionized water into it, stir evenly. At this time, the sulfuric acid dilution will release heat. Then put the beaker into a 110-120℃ oil bath (the temperature of the oil bath varies depending on the season). Continue heating and stirring. Start timing when the temperature of the mixture in the beaker reaches 95-100℃ (98℃ is preferred). Stop heating after 15 minutes and take the beaker out of the oil bath.

[0056] ① Slow etching at room temperature: Add 1.4L of deionized water to a beaker, along with 25mL of 30% hydrogen peroxide (approximately 10mol / L). Stir vigorously for 1 hour. Then, let the mixture stand and allow the slow etching reaction to proceed at room temperature for 12 hours. After 12 hours, remove 1.0L of the supernatant and add 1.0L of deionized water and 2mL of 30% hydrogen peroxide (approximately 10mol / L). Stir for 1 hour, let the mixture stand, and continue the slow etching reaction at room temperature for another 12 hours. Repeat this process two more times.

[0057] ⑤ Washing: After the slow etching is completed, the graphene paste is centrifuged and washed with deionized water until it becomes neutral.

[0058] ⑥ Reduction Treatment: Disperse a certain amount of the prepared graphene paste in 1000 mL of deionized water and sonicate for 30 minutes to obtain a 1 mg / mL dispersion. Add 25 mL of 30% ammonia and 6 mL of 80% hydrazine hydrate. Reflux in a 95°C oil bath for 3 hours, then add 4 mL of 80% hydrazine hydrate and allow to react for 30 minutes. After the reaction, add 4% hydrochloric acid until the graphene floats. Filter and wash while hot. Freeze-dry to obtain self-synthesized graphene. Our graphene preparation process incorporates a low-temperature etching step, producing graphene with a complete lamellar structure and numerous point vacancy defects.

[0059] 2. Preparation of silver-loaded graphene antibacterial materials containing a large number of Ag single atoms by impregnation and calcination

[0060] (1) Impregnation:

[0061] ① Preparation of salt solution: First, the water absorption of self-synthesized graphene was measured to be 7.5 mL / g. Therefore, 0.5 g of graphene was used as the carrier, and the volume of the impregnation solution for equal volume was 3.75 mL. 284.9 mg (0.5 mmol) of Ag(NO3) was dissolved in deionized water to make 3 mL of salt solution. 0.75 mL of anhydrous ethanol was added, shaken, and sealed for storage.

[0062] ②Immersion: Take 500mg of graphene powder, spread it on a watch glass, and place it on a stand in a container containing ethanol liquid. Leave it in a sealed container for 1 hour. The ethanol vapor will adsorb on the graphene surface. Then remove the graphene powder and quickly add it to the beaker solution prepared in ①. Stir continuously with a glass rod to ensure rapid contact between the graphene and the liquid. Then, let the sample stand at room temperature for 3 hours.

[0063] ③ Drying: Place the sample in a vacuum drying oven at 50°C for 12 h, and then grind the sample into powder using an agate mortar.

[0064] (2) Calcination:

[0065] The powdered sample prepared in step (1) was placed in a quartz tube, placed in a tube furnace, and heated from room temperature to 500°C at a rate of 5°C / min under a nitrogen atmosphere, and calcined at 500°C for 2 h. When the temperature dropped to room temperature, ventilation was stopped, and the sample was taken out and sealed for storage.

[0066] 3. Characterization Results

[0067] The catalyst was characterized using high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM): a very small amount of sample was ultrasonically dispersed in an ethanol solution, and the sample was prepared with a copper grid and placed in the instrument for testing. Figure 1 ,Depend on Figure 1 It can be seen that a lot of single-atom Ag is evenly loaded on the graphene and the distribution is relatively uniform. The antibacterial effect of Example 1 is as follows: Figure 4 , Figure 5 As shown in Table 1, an excellent antibacterial effect was achieved.

[0068] Application Example 1

[0069] The antibacterial test was performed using the Ag single-atom graphene antibacterial material shown in Example 1. The experimental method is as follows:

[0070] 1. Accurately weigh 0.01 g of sample and place it in a small test tube. Autoclave at 115°C for 20 min and set aside.

[0071] 2. Use activated Staphylococcus aureus (Staphylococcus aureus ATCC29213) to prepare a 0.5 McFarland suspension with sterile saline.

[0072] 3. Inoculate 0.5 ml of Staphylococcus aureus suspension into MHB medium to a final concentration of 104 cfu / mL. Take 1 mL and 2 mL respectively and add them to the small test tube containing the sample. Place the tube in a shaker at 37°C and culture at 150 rpm for 20 h. Count the colonies using the doubling dilution method and calculate the inhibition rate.

[0073] 4. Calculation method of antibacterial rate

[0074] Viable bacteria count (cfu / mL) = plate count result × dilution factor × 100

[0075] Bactericidal rate (%) = (average number of viable bacteria in the control - average number of viable bacteria in the treatment) / average number of viable bacteria in the control × 100%

[0076] 1. Antibacterial effect of mixed culture in MHB medium (MIC method)

[0077] like Figure 4 As shown, the MHB culture medium of the sample in Example 1 is transparent, indicating that its MIC is less than 0.5 mg / mL

[0078] 2. Limiting dilution plate count results

[0079] like Figure 5 As shown, the control had a large amount of bacterial growth, the blank control had no bacterial growth, and the sample of Example 1 had no bacterial growth, indicating that the sample could kill the test bacteria at 0.5 mg / mL.

[0080] 3. Results of viable bacterial count (cfu / mL) and antibacterial rate (%)

[0081] Table 1 Results of viable bacterial count (cfu / mL) and antibacterial rate (%)

[0082]

[0083] As shown in Table 1, the antibacterial rate of Staphylococcus aureus was calculated using the antibacterial rate calculation results in the method. The results showed that the antibacterial rate of the sample in Example 1 was 100%.

[0084] In summary, the Ag single-atom-graphene antibacterial material protected by the present invention and its preparation technology are characterized by large single-atom loading, uniform distribution, and good stability. The preparation method is suitable for industrial large-scale production. Antibacterial testing has shown significant advantages and application value.

Claims

1. An Ag single atom-graphene antibacterial material, characterized in that: The carrier of the material is graphene, which contains a large number of point vacancy defects and a complete layer structure; Ag is uniformly loaded on the graphene at a high density of single atoms; The metal component carried by the material may also contain one or more of Cu, Zn, Fe, Co, Ni, and Mo metal components.

2. A method for preparing an Ag single atom-graphene antibacterial material, characterized in that: The following steps are involved: (1) Preparation of graphene carriers containing a large number of point vacancy defects: ① Low-temperature reaction: Add 230 mL of concentrated sulfuric acid and 5.0 g of sodium nitrate to a container and stir thoroughly in an ice bath. When the temperature is less than 5°C, add 10.0 g of graphite powder and stir evenly for 2.5 hours. Then weigh 30.0 g of potassium permanganate and slowly add it to the mixture. During the addition, control the system temperature not to exceed 20°C. ②Medium temperature reaction: Transfer the container from step ① to a 35℃ constant temperature water bath and stir for 2h; ③ High temperature reaction: Take out the container and add 460mL of deionized water into it, stir evenly, place the container in a 110-120℃ oil bath, continue heating and stirring, start timing when the temperature of the mixture in the beaker reaches 95-100℃, stop heating after 15 minutes, and take the container out of the oil bath; ④ Slow etching reaction at room temperature: add 1.4L deionized water to the container, add 25mL hydrogen peroxide simultaneously, stir vigorously for 1h, then let it stand, slowly etch at room temperature for 12h, remove 1.0L of the supernatant, add 1.0L deionized water, add 1-10mL hydrogen peroxide, stir for 1h, let it stand, and continue to slowly etch at room temperature for 12h. Repeat this process 1-3 times; ⑤ Washing: After slow etching is completed, the graphene paste is washed with deionized water by centrifugation until it is neutral, or dialyzed until it is neutral; ⑥ Reduction treatment: Take a certain amount of the prepared graphene paste, disperse it in 1000 mL of deionized water, and ultrasonicate it for 30 min to prepare a 1 mg / mL dispersion. Add 25 mL of 30% ammonia water and 6 mL of 80% hydrazine hydrate, reflux in an oil bath at 95 ° C for 3 h, then add 4 mL of 80% hydrazine hydrate and react for 30 min. After the reaction, add 4% hydrochloric acid solution until the graphene floats up. Filter it while hot, wash it, and then freeze-dry it to obtain hydrogen-rich graphene; (2) Impregnation: The graphene prepared in step (1) is moistened with an organic solvent, added to a salt solution, rapidly stirred to dissolve, allowed to stand at room temperature, vacuum dried, and then ground into powder; (3) Calcination: The powdered sample prepared in step (2) was calcined at 500°C for 2 h under a nitrogen atmosphere. When the temperature dropped to room temperature, ventilation was stopped, and the sample was taken out and sealed for storage.

3. The method for preparing the Ag single atom-graphene antibacterial material according to claim 2, wherein: The salt solution in step (2) is a mixed solution of nitrate, water and an organic solvent, and the volume of the salt solution is just absorbed by the hydrogen-rich graphene carrier.

4. The method for preparing the Ag single atom-graphene antibacterial material according to claim 2, wherein: The total amount of salt in the salt solution in step (2) is 0.1-4.0 mmol / g carrier, wherein the amount of Ag is 0.05-2.0 mmol / g carrier.

5. The method for preparing the Ag single atom-graphene antibacterial material according to claim 2, wherein: The ethanol wetting time in step (2) is 1 to 3 hours.

6. The method for preparing the Ag single atom-graphene antibacterial material according to claim 2, wherein: The calcination in step (2) is carried out by heating the temperature from room temperature to 500°C at a rate of 10°C / min.

7. The method for preparing the Ag single atom-graphene antibacterial material according to claim 2, wherein: The organic solvent in step (2) is any one of ethanol, methanol, acetone, tetrahydrofuran, formic acid and acetic acid.

8. The method for preparing the Ag single atom-graphene antibacterial material according to claim 2, wherein: The volume ratio of water to organic solvent in step (2) is 1:0 to 0:

1.

9. An application of Ag single atom-graphene antibacterial material, characterized in that: Used to prepare antibacterial resins or plastics.

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