A method for preparing a highly efficient silver single-atom bactericidal material

Abstract

This invention relates to a method for preparing a highly efficient silver single-atom bactericidal material. The invention utilizes an oxide as a carrier, modifies the oxide surface with phenolic compounds, anchors silver ions with phenolic hydroxyl groups to achieve uniform dispersion, and finally reduces the silver ions to silver single atoms via hydrogen reduction, ultimately obtaining a single-atom silver catalyst supported on the oxide carrier surface. This invention uses inexpensive, mass-producible commercial oxides as carriers, and through two simple steps—phenolic compound modification and hydrogen reduction—obtains a highly efficient single-atom silver bactericidal material with a low loading. The preparation steps are simple, the synthesis time is short, no large-scale equipment is required, it is easy to promote and apply, and it has a wide range of applications, suitable for bactericidal use on both solid surfaces and inside liquids.

Description

Technical Field

[0001] This invention relates to a method for preparing a highly efficient silver single-atom bactericidal material, belonging to the field of materials preparation technology. Background Technology

[0002] For a long time, various bacteria and viruses have posed a constant threat to human health. With the continuous advancement of science and technology, people's requirements for environmental hygiene have become increasingly stringent, making the preparation and application of bactericidal materials particularly important. Silver nanoparticles, due to their excellent chemical stability, broad-spectrum bactericidal activity, and long-lasting antibacterial effect, are widely used in food safety, burn dressings, safe skincare products, bionic medicine, wastewater treatment, and agriculture and animal husbandry, making them the most widely used engineering nanomaterials to date.

[0003] Researchers have loaded silver nanomaterials onto various materials to create bactericides. However, despite their excellent bactericidal properties, supported silver nanomaterials face several challenges that hinder their large-scale application in this field. For example, 1) due to their high surface energy, silver nanomaterials easily aggregate during use, significantly weakening their bactericidal effect; 2) the silver loading in bactericidal materials is large, resulting in high costs; and 3) excessive silver dispersion in the environment can have adverse effects on the ecosystem and human health. Therefore, improving the bactericidal efficiency of silver while minimizing the silver loading to achieve optimal results is a crucial and challenging problem, and represents the future development direction for silver-based bactericides.

[0004] In recent years, single-atom materials have shown higher activity and stability than metal nanoparticles in many fields due to their 100% atomic utilization and tunable structure. At present, the main methods for preparing single-atom materials are co-precipitation, impregnation, and atomic layer deposition. These methods are subject to harsh conditions, complex steps, and high costs, making them unsuitable for industrial production.

[0005] Chinese patent document CN114832813A discloses a silver-based single-atom catalyst for water treatment and its preparation method. This method involves adsorbing a silver source solution with zirconium hydrogen phosphate, then mixing it with butyl acrylate-styrene-acrylonitrile (ASA) resin to prepare ASA material via melt blending. The ASA material is then carbonized at high temperature under a nitrogen atmosphere, and finally reduced under a hydrogen atmosphere to generate the silver-based single-atom catalyst for water treatment. This method first uses zirconium hydrogen phosphate to adsorb the silver source, then fixes it with ASA resin, carbonizes it at high temperature, and then uses in-situ reduction to obtain the silver-based single-atom catalyst. It requires carbonization of the ASA material, making the process complex, costly, and energy-intensive.

[0006] Therefore, there is an urgent need for a simple, quick, and efficient method for preparing single-atom silver bactericides. Summary of the Invention

[0007] The purpose of this invention is to address the problems of complex preparation steps, high cost, and high energy consumption of silver single-atom bactericidal materials, and to propose an efficient preparation method for silver single-atom bactericidal materials. Another purpose of this invention is to provide silver single-atom bactericidal materials obtained by the above preparation method.

[0008] The technical solution of this invention is as follows: using an oxide as a carrier, phenolic compounds are modified onto the oxide, and then silver ions are anchored by the phenolic hydroxyl groups of the phenolic compounds to achieve uniform dispersion. Finally, the silver ions are reduced to silver single atoms through hydrogen reduction. This invention obtains a highly efficient single-atom silver bactericidal material with low loading through two simple steps: phenolic compound modification and hydrogen reduction. In this material, silver is uniformly distributed on the carrier in the form of single atoms, achieving excellent bactericidal effects. Furthermore, this method has a simple process flow and can be mass-produced; it can be applied to the sterilization of kitchens in food factories and restaurants, processing areas in supermarkets, and also to the sterilization of coatings, clothing, and the surfaces of daily chemical solids.

[0009] The specific technical solution of this invention is as follows:

[0010] A method for preparing a highly efficient silver single-atom bactericidal material includes the following steps:

[0011] 1) Mix the oxide support and the aqueous solution of the phenolic compound, stir in the dark, centrifuge, wash, and vacuum dry to obtain the oxide modified with the phenolic compound;

[0012] 2) Phenolic compound-modified oxides and silver ion solutions are added to an organic solvent, stirred evenly, rotary evaporated, and vacuum dried. The dried solid is then subjected to a reduction reaction under a hydrogen atmosphere to prepare a silver single-atom bactericidal material with oxide as the carrier.

[0013] According to a preferred embodiment of the present invention, in step 1), the particle size of the oxide is 5 nm-2 μm, and the oxide is titanium oxide, aluminum oxide, zirconium oxide, iron oxide or silicon oxide.

[0014] According to a preferred embodiment of the present invention, in step 1), the titanium oxide is anatase, rutile, or P25 type titanium oxide, the aluminum oxide is α / γ-alumina, and the iron oxide is iron(III) oxide or α / γ-iron oxide.

[0015] According to a preferred embodiment of the present invention, in step 1), the phenolic compound is catechol, hydroquinone, phloroglucinol, or pyroglucinol.

[0016] Most preferably, in step 1), the phenolic compound is catechol.

[0017] According to the present invention, in step 1), the concentration of the aqueous solution of phenolic compound is 0.01-10M; more preferably, in step 1), the concentration of the phenolic compound solution is 0.05-5M; and most preferably, in step 1), the concentration of the phenolic compound solution is 0.1-2M.

[0018] According to a preferred embodiment of the present invention, in step 1), the mass-to-volume ratio of the oxide support to the aqueous solution of the phenolic compound is (1-10):(80-200), unit: g / mL.

[0019] According to a preferred embodiment of the present invention, in step 1), the reaction time for stirring in the dark is 2-24 h, the reaction temperature is 20-150 °C, the centrifugation speed is 3000-12000 rpm, and the centrifugation time is 5-15 min; the vacuum drying temperature is 50-150 °C, and the vacuum drying time is 2-48 h.

[0020] According to a preferred embodiment of the present invention, in step 2), the concentration of the silver ion solution is 0.1-40 mg / mL.

[0021] More preferably, in step 2), the concentration of the silver ion solution is 1-10 mg / mL.

[0022] Most preferably, in step 2), the concentration of the silver ion solution is 2-5 mg / mL.

[0023] According to a preferred embodiment of the present invention, in step 2), the mass ratio of silver ions in the silver ion solution to the oxide support modified by the phenolic compound solution is 0.2-5:100.

[0024] According to a preferred embodiment of the present invention, in step 2), the source of the silver ion solution is silver nitrate solution or silver perchlorate solution.

[0025] According to a preferred embodiment of the present invention, in step 2), the organic solvent is acetonitrile, acetone, N,N-dimethylformamide, methanol, or ethanol.

[0026] Most preferably, in step 2), the organic solvent is acetonitrile.

[0027] According to a preferred embodiment of the present invention, in step 2), the volume ratio of silver ion solution to organic solvent is 1:30-50, the stirring time is 0.5-10h, the vacuum drying temperature is 20-80℃, and the vacuum drying time is 2-48h.

[0028] According to a preferred embodiment of the present invention, in step 2), the reduction reaction specifically involves raising the temperature from 25-40°C to 100-500°C at a heating rate of 0.5-10°C / min, holding the temperature for 1-5 hours, and using hydrogen gas as a hydrogen-nitrogen mixture or pure hydrogen gas with a volume ratio of 5%.

[0029] The present invention modifies an oxide with a phenolic compound, and then anchors silver ions through the phenolic hydroxyl groups of the phenolic compound, so that the silver atoms are fixed on the surface of the support and do not agglomerate.

[0030] A single-atom silver bactericidal material is prepared by the method described above.

[0031] The aforementioned single-atom silver bactericidal materials are used for sterilization in kitchens of food factories, restaurants, processing areas in supermarkets, coatings, clothing, or solid surfaces of daily chemical products.

[0032] In this invention, the phenolic hydroxyl groups of phenolic compounds are used for silver ion anchoring and uniform dispersion, preventing the aggregation of final silver atoms and ensuring that all silver atoms are converted into single-atom silver, thus avoiding the formation of silver nanoparticles. Catechol shows the best effect among these compounds. Therefore, the phenolic compounds of this invention can significantly improve the formation of single-atom silver. The final silver single atoms are fixed by phenolic hydroxyl groups covalently attached to the oxide surface, and the silver single atoms exhibit a low valence state close to zero. The silver single-atom material prepared by this invention exhibits superior bactericidal activity compared to silver nanoparticles.

[0033] Technical features and advantages of the present invention:

[0034] 1. The method of this invention utilizes an oxide as a carrier, modifies the oxide with phenolic compounds, anchors and uniformly disperses silver ions through phenolic hydroxyl groups, and finally reduces the silver ions to silver single atoms through hydrogen reduction. These silver single atoms are then loaded onto the oxide modified with phenolic compounds. The silver single atoms are stabilized by the phenolic hydroxyl groups on the oxide surface, allowing them to remain stable under strong reducing conditions, preventing the aggregation of silver atoms, improving the stability of the silver single atoms, and ensuring the strong and long-lasting bactericidal effect of the bactericidal material.

[0035] 2. The single-atom bactericidal material obtained by this invention can greatly reduce the amount of silver used, but has a stronger bactericidal effect than nano-sized silver particles, achieving a high bactericidal efficiency in a short time.

[0036] 3. This invention produces a single-atom silver bactericidal material through two simple steps: phenolic compound modification and hydrogen reduction. The steps are simple, the synthesis time is short, no large equipment is required, and it is easy to promote and apply.

[0037] 4. The single-atom silver bactericidal material of the present invention has a wide range of applications. It can be used for sterilization of solid surfaces and liquid interiors. It can be applied to sterilization of kitchens in food factories, restaurants, and processing areas in supermarkets. It can also be applied to sterilization of coatings, clothing, and solid surfaces of daily chemical products. Attached Figure Description

[0038] Figure 1a Aberration-corrected transmission electron microscope image of the single-atom silver bactericidal material prepared in Example 1.

[0039] Figure 1b Transmission electron microscope image of the single-atom silver bactericidal material prepared in Example 1.

[0040] Figure 1c These are electron spin resonance spectra of different materials.

[0041] Figure 1d A high-magnification transmission electron microscope image of the bactericidal material composed of single-atom silver and silver nanoparticles prepared for Comparative Example 1.

[0042] Figure 1e Low-magnification transmission electron microscope image of the bactericidal material prepared for Comparative Example 2.

[0043] Figure 2 Transmission electron microscope image of the silver nanoparticle bactericidal material prepared for Comparative Example 3.

[0044] Figure 3 The diagram shows the bactericidal kinetics of different bactericidal materials.

[0045] Figure 4a Photographs showing the bactericidal effect of the single-atom bactericidal material prepared in Example 1.

[0046] Figure 4b The image shows the bactericidal effect of the silver nanoparticle bactericidal material prepared in Comparative Example 3.

[0047] Figure 5 The image shows the bactericidal effect of the mixed bactericidal material of single-atom silver and silver nanoparticles prepared in Comparative Example 2.

[0048] Figure 6 The image shows the diffuse ultraviolet reflectance spectra of different bactericidal materials.

[0049] Figure 7 Here are the XRD patterns of different bactericidal materials. Detailed Implementation

[0050] Detailed embodiments shown: In order to enable those skilled in the art to fully understand the technical solution and beneficial effects of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings.

[0051] Example 1

[0052] The preparation method of silver single-atom bactericidal material is as follows:

[0053] 1) Add 1g of TiO2 (rutile, 100nm, hydrophilic) to a flask, add 200mL of 0.1mol / L catechol aqueous solution, and stir in the dark for 12h; after stirring, centrifuge the reaction solution at 10000rpm for 8min to remove the supernatant; wash the solid three times with deionized water, and then dry it in a vacuum drying oven at 60℃ for 20h to obtain catechol-modified TiO2;

[0054] 2) Add 500 mg of catechol-modified TiO2 and 0.5 mL of a 3.15 mg / mL silver nitrate solution to 20 mL of acetonitrile. Stir in the dark for 30 min, remove the acetonitrile by rotary evaporation, and dry in a vacuum drying oven at 60 °C for 4 h. Place the dried solid in a crucible and put it in a tube furnace. Under a hydrogen atmosphere, heat to 200 °C at a rate of 5 °C / min and hold for 2 h. Then allow it to cool naturally to room temperature to obtain the silver single-atom bactericidal material SAAg / TiO2. 2(邻苯二酚) .

[0055] Aberration-corrected electron microscope image of the single-atom silver bactericidal material prepared in this embodiment is shown below. Figure 1a ,pass Figure 1a As can be seen, the single-atom bactericidal material SAAg / TiO in this embodiment... 2(邻苯二酚) It is a single atom; see transmission electron microscope image. Figure 1b The electron spin resonance spectrum is shown below. Figure 1c The ultraviolet diffuse reflectance spectrum is shown below. Figure 6 XRD pattern can be found Figure 7 .

[0056] Example 2

[0057] The method for preparing the high-efficiency silver single-atom bactericidal material described in Example 1 differs from that in:

[0058] In step 1), the concentration of the catechol aqueous solution was 1.5 mol / L, and the rest was carried out as in Example 1.

[0059] Example 3

[0060] The method for preparing the high-efficiency silver single-atom bactericidal material described in Example 1 differs from that in:

[0061] In step 2), the amount of catechol-modified titanium dioxide used is 100 mg, and the rest is carried out as in Example 1.

[0062] Example 4

[0063] The method for preparing the high-efficiency silver single-atom bactericidal material described in Example 1 differs from that in:

[0064] In step 2), after introducing pure hydrogen gas for 10 minutes, the temperature is increased to 240°C at a rate of 5°C / min and maintained for 2 hours. The rest is carried out as in Example 1.

[0065] Comparative Example 1

[0066] The method for preparing the high-efficiency silver single-atom bactericidal material described in Example 1 differs from that in:

[0067] In step 1), replace the catechol aqueous solution with a resorcinol aqueous solution.

[0068] Finally, a bactericidal material SAAg+AgNPs / TiO2, consisting of a mixture of silver single atoms and silver nanoparticles, was obtained. 2(间苯二酚) .

[0069] Single-atom silver and silver nanoparticle mixed bactericidal material SAAg+AgNPs / TiO 2(间苯二酚) High-magnification transmission electron microscope images are shown below. Figure 1d The ultraviolet diffuse reflectance spectrum is shown below. Figure 6 When the aqueous solution of resorcinol was replaced with the aqueous solution of catechol, nanoparticles were observed in the product under high magnification, indicating the formation of nano-silver.

[0070] Comparative Example 2

[0071] The method for preparing the high-efficiency silver single-atom bactericidal material described in Example 1 differs from that in:

[0072] In step 1), replace the catechol aqueous solution with an aqueous phenol solution.

[0073] The obtained low-magnification transmission electron microscope images of the product are shown below. Figure 1e ,pass Figure 1e It can be seen that after replacing the catechol aqueous solution with the phenol aqueous solution, a small number of nanoparticles can be seen in the product even under low magnification transmission, indicating the formation of nano-silver.

[0074] Comparative Example 3

[0075] The preparation method is the same as that described in Example 1, except that:

[0076] Step 2) Using unmodified titanium dioxide directly, silver nanoparticle bactericidal material AgNPs / TiO2 is obtained.

[0077] Transmission electron microscopy image of the silver nanoparticle bactericidal material AgNPs / TiO2 is shown below. Figure 2 ,pass Figure 2 As can be seen, AgNPs / TiO2 are silver nanoparticles, and their electron spin resonance spectra are shown below. Figure 1c The ultraviolet diffuse reflectance spectrum is shown below. Figure 6Therefore, unmodified titanium dioxide will only yield silver nanoparticles, not silver single atoms.

[0078] Comparative Example 4

[0079] Preparation of blank control material 1:

[0080] Untreated titanium oxide was placed directly into a crucible and placed in a tube furnace. Pure hydrogen was introduced for 10 minutes, and the temperature was raised to 200°C at a rate of 5°C / min and held for 2 hours. Then, it was allowed to cool naturally to room temperature to obtain TiO2-H material treated only by hydrogen reduction.

[0081] The electron spin resonance spectrum of the material prepared in Comparative Example 4 is shown in Figure 4. Figure 1c .

[0082] Comparative Example 5

[0083] Preparation of blank control material 2

[0084] Add 1g of TiO2 (rutile, 100nm, hydrophilic) to a flask, add 200mL of 0.1mol / L catechol solution, and stir in the dark for 12h. After stirring, transfer the reaction solution to several 50mL centrifuge tubes, weigh and balance them, and then centrifuge them at 10000rpm for 8min to remove the supernatant. Wash the solid three times with deionized water, and then dry it in a vacuum drying oven at 60℃ for 20h to obtain catechol-treated titanium dioxide (TiO2). 2(邻苯二酚) .

[0085] Catechol-treated titanium dioxide (TiO2) 2(邻苯二酚) The ultraviolet diffuse reflectance spectrum is shown below. Figure 6 XRD pattern can be found Figure 7 .

[0086] Experimental Example

[0087] sterilization experiment

[0088] (1) Prepare Luria-Bertani (LB) solid culture medium and liquid culture medium respectively.

[0089] Solid culture medium: 2.5g yeast extract, 5g sodium chloride, 5g tryptone, 9g agar, 500mL deionized water.

[0090] Liquid culture medium: 2.5g yeast extract, 5g sodium chloride, 5g tryptone, 500mL deionized water.

[0091] Solid and liquid culture media are sterilized by high temperature and high pressure.

[0092] (2) Bacteria were cultured in LB liquid medium for 24 hours, and the resulting bacterial culture was diluted to 10⁻⁶. 7 Take 5 mL of diluted bacterial solution and mix it with the bactericide (the concentration of the bactericide is 15 mg / mL). Place it in a shaking incubator (37℃, 180 rpm / min) and shake. Every 20 min, take 50 μL of bacterial solution and spread it on the surface of the solid culture medium. Then place it in a 37℃ incubator for growth. Take 3 parallel samples for each group.

[0093] SAAg / TiO2 in Example 1 after 1 hour of sterilization 2(邻苯二酚) The number of colonies grown in the culture medium is shown below. Figure 4a The number of colonies grown on the AgNPs / TiO2 medium in Example 3 is shown in the figure. Figure 4b .

[0094] SAAg / TiO in Example 1 2(邻苯二酚) The bactericidal kinetics of AgNPs / TiO2 in the first 3 hours compared with Comparative Example 3 are shown below. Figure 3 ,pass Figure 3 It is evident that the bactericidal effect of the single-atom silver bactericidal material synthesized by this invention is significantly better than that of the silver nanoparticle bactericidal material.

[0095] Figure 5 Comparative Example 1: A bactericidal material composed of single-atom silver and silver nanoparticles, SAAg+AgNPs / TiO2. 2(间苯二酚) A diagram illustrating the sterilization effect after 1 hour. (Compared with...) Figure 4a In comparison, the bactericidal effect is significantly weaker than that of Example 1 of the present invention.

Claims

1. A method for preparing a silver single-atom bactericidal material, comprising the following steps: 1) The oxide support and the aqueous solution of the phenolic compound were mixed, stirred in the dark, centrifuged, washed, and vacuum dried to obtain the phenolic compound-modified oxide; the oxide support was titanium oxide, and the phenolic compound was catechol; 2) Phenolic compound-modified oxides and silver ion solutions are added to an organic solvent, such as acetonitrile, acetone, N,N-dimethylformamide, methanol, or ethanol. The mixture is stirred until homogeneous, rotary evaporated, and vacuum dried. The dried solid is then subjected to a reduction reaction under a hydrogen atmosphere to prepare a silver single-atom bactericidal material with oxide as the carrier.

2. The preparation method according to claim 1, characterized in that, In step 1), the concentration of the phenolic compound solution is 0.05-5M.

3. The preparation method according to claim 1, characterized in that, In step 1), the mass-volume ratio of the oxide support to the aqueous solution of the phenolic compound is (1-10):(80-200), unit: g / mL. The particle size of the oxide support is 5 nm - 2 μm, and the titanium dioxide is anatase, rutile, or P25 type titanium dioxide.

4. The preparation method according to claim 1, characterized in that, In step 1), the reaction time is 2-24 hours with stirring in the dark, and the reaction temperature is 20-150°C. o C. Centrifugation speed: 3000-12000 rpm; centrifugation time: 5-15 min; vacuum drying temperature: 50-150°C. o C, vacuum drying time is 2-48 h.

5. The preparation method according to claim 1, characterized in that, In step 2), the concentration of the silver ion solution is 2-5 mg / mL, and the mass ratio of silver ions to the oxide support modified by the phenolic compound solution in the silver ion solution is 0.2-5:

100.

6. The preparation method according to claim 1, characterized in that, In step 2), the silver ion solution is derived from silver nitrate solution or silver perchlorate solution, the volume ratio of silver ion solution to organic solvent is 1:30-50, the stirring time is 0.5-10 h, and the vacuum drying temperature is 20-80°C. o C, vacuum drying time is 2-48 h, and the reduction reaction is specifically carried out at 0.5-10 o Heating rates from 25-40 °C / min o C rises to 100-500 o C, the heat preservation time is 1-5 h, and the hydrogen gas is a hydrogen-nitrogen mixture with a volume ratio of 5% or pure hydrogen gas.

7. A single-atom silver bactericidal material, prepared by the method described in any one of claims 1-6.

8. The application of the single-atom silver bactericidal material according to claim 7, for sterilization in food factories, restaurant kitchens, supermarket processing areas, clothing or daily chemical solid surfaces.

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