La / Cu diatomic nano bactericidal material and preparation method thereof

Abstract

The invention relates to the technical field of monatomic bactericidal materials, in particular to a La / Cu diatomic nano bactericidal material and a preparation method thereof. The La / Cu diatomic nano bactericidal material comprises a calcium carbonate carrier and metal monoatoms dispersed in the calcium carbonate carrier in a monatomic form, the metal monoatoms are La and Cu, the La loading capacity is 1-8 wt%, and the Cu loading capacity is 1-15 wt%; and the particle size of the calcium carbonate carrier is 50-1000nm. Compared with a traditional Cu-based bactericidal material, through directional introduction of La and La / Cu double-atom collaborative design, precise regulation and control of the valence state of Cu are achieved, the high-activity Cu proportion is remarkably increased, and the minimum antibacterial concentration MIC is greatly reduced, that is, under the same Cu loading capacity, the MIC value can be effectively reduced through addition of La, the total loading amount of Cu can be effectively reduced, the soil accumulation risk caused by high Cu loading is avoided, and the antibacterial effect is improved. The high efficiency and the environment-friendly property are both considered.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of single-atom bactericidal materials, in particular to a La / Cu diatomic nanometer bactericidal material and a preparation method thereof. BACKGROUND

[0002] Among the materials for preventing and controlling bacterial diseases, copper-based bactericidal materials have become one of the most widely used categories due to their clear bactericidal mechanism (destroying bacterial cell membranes and inhibiting enzyme activity), relatively good environmental compatibility, and effectiveness against a variety of agricultural pathogens. They are widely used in soil disinfection, foliar spraying, and other scenarios.

[0003] However, the bactericidal efficiency of traditional Cu-based materials still has an upper limit, and in practical applications, performance needs to be improved through various methods, but these methods have the following disadvantages in agricultural scenarios: ①Enhance bactericidal effect by increasing Cu load. However, excessive Cu will lead to a sharp increase in material cost, and is easy to accumulate in the soil, disrupting the soil micro-ecological balance, and even causing heavy metal poisoning of crops, which is contrary to the concept of green agriculture.

[0004] ②Strengthen the enzyme-like activity of Cu by adding exogenous catalytic substrates (such as hydrogen peroxide, light), such as the copper bactericidal device with ultraviolet light combination disclosed in Chinese patent CN2024218765083 and the complex bactericide disclosed in Chinese patent CN2024106818510, which includes: oxalic acid copper 6%-10% dipropyl ketone amine, natamycin 30%-40%, ultraviolet light absorber 10%-12%, dispersing agent 3%-10%, wetting agent 3%-7%, penetrating agent 0.2%-1.0%, and filler to make up 100%. The ultraviolet light absorber prepared by the present application achieves the purpose of improving the stability of the bactericide composition. However, in agricultural scenarios, exogenous substrates are easily washed away by rainwater, adsorbed by soil, or decomposed by microorganisms, making it difficult to maintain an effective concentration, and additional spraying equipment and operation steps are required, significantly increasing the cost of field management, and the practical application feasibility is extremely low.

[0005] ③ Through the use of noble metals (silver, gold, platinum, rubidium, etc.) or expensive carriers (graphene, antimicrobial peptides, etc.) to enhance the synergistic bactericidal effect, such as a RuCu double-atom catalyst loaded in Chinese patent CN2025100709707, a nitrogen-doped porous carbon material is prepared by using a nitrogen-containing porous organic polymer and nano calcium carbonate, mixed with the active component RuCu double precursor, ball milled, calcined and reduced to obtain. For example, the formula process of a graphene / cuprous oxide sterilization spray disclosed in Chinese patent CN2025103820960, a certain amount of graphene oxide is first dispersed in deionized water, a brown solution is obtained by ultrasonic treatment, a dispersion solution is prepared by using ethanol, white wine, hydrogen peroxide, moisturizing agent, additive and pure water, the appropriate moisturizing agent and additive are selected, the graphene / cuprous oxide powder is uniformly mixed with the dispersion solution, the graphene / cuprous oxide antibacterial disinfectant spray is diluted, and the graphene / cuprous oxide antibacterial disinfectant spray is diluted again. The preparation method and application of a soluble nano copper peroxide with photo-thermal and targeted antibacterial function disclosed in Chinese patent CN2025103090258, the preparation method steps are as follows: add copper sulfate pentahydrate to the aqueous solution of lactoferrin, add pH regulator dropwise, then add hydrogen peroxide solution for reaction, and then dialysis and freeze-drying to obtain. The high cost of noble metals and carriers in the above-mentioned existing antibacterial materials makes it impossible to adapt to large-scale agricultural applications, and the biological safety of noble metals has not been fully determined, which may pose potential environmental risks.

[0006] Therefore, the existing technology is difficult to balance between "high efficiency", "controllable cost" and "simple operation", and a new technical path is needed to break through the inherent activity bottleneck of Cu-based materials and not rely on high loading, exogenous substrate or noble metal composite to fundamentally solve the application pain points of agricultural bactericidal materials. Therefore, the inventors provide a La / Cu double-atom nano bactericidal material and a preparation method thereof. SUMMARY

[0007] In order to solve the above-mentioned problems existing in the prior art, the present application provides a La / Cu double-atom nano bactericidal material and a preparation method thereof.

[0008] The La / Cu double-atom nano bactericidal material provided by the present application is realized by the following technical scheme: A La / Cu double-atom nano bactericidal material includes a calcium carbonate carrier and a metal monatomic atom dispersed in the calcium carbonate carrier in a monatomic form, the metal monatomic atom is a monatomic La and a monatomic Cu; the loading amount of the monatomic La is 1-8wt%; the loading amount of the monatomic Cu is 1-15wt%; the particle size of the calcium carbonate carrier is 50-1000nm.

[0009] Compared with traditional Cu-based bactericidal materials, this invention achieves precise control of Cu valence state through the directional introduction of La and the La / Cu dual-atom synergistic design, significantly increasing the proportion of highly active Cu⁺ and greatly reducing the minimum antibacterial concentration (MIC). That is, under the same Cu loading, the addition of La can effectively reduce the MIC value, effectively reduce the total Cu loading, avoid the risk of soil accumulation caused by high Cu loading, and balance high efficiency and environmental protection.

[0010] Preferably, the La / Cu diatomic nano-bacterial material has a minimum antibacterial concentration (MIC) of ≤10 μg / mL based on Ralstonia solanacearum, ≤10 μg / mL based on Bacillus thuringiensis, ≤10 μg / mL based on Ralstonia solanacearum, ≤10 μg / mL based on Bacillus subtilis, and ≤10 μg / mL based on Corynebacterium circumferentiale.

[0011] Preferably, the loading of single-atom Cu in the La / Cu diatomic nano-bactericidal material is 1 wt%, and the loading of single-atom La is 15 wt%. Then, the minimum antibacterial concentration (MIC) of the La / Cu diatomic nano-bactericidal material based on Ralstonia solanacearum is ≤0.20 μg / mL, the minimum antibacterial concentration (MIC) based on Bacillus thuringiensis is ≤0.20 μg / mL, the minimum antibacterial concentration (MIC) based on Ralstonia solanacearum is ≤0.25 μg / mL, and the minimum antibacterial concentration (MIC) based on Bacillus is ≤0.20 μg / mL.

[0012] Preferably, the loading of single-atom Cu in the La / Cu diatomic nano-bactericidal material is 1 wt%, and the loading of single-atom La is 8 wt%. Therefore, the minimum antibacterial concentration (MIC) of the La / Cu diatomic nano-bactericidal material based on *Ralstonia solanacearum* is ≤10 μg / mL, the minimum antibacterial concentration (MIC) based on *Bacillus subtilis* is ≤10 μg / mL, the minimum antibacterial concentration (MIC) based on *Ralstonia solanacearum* is ≤10 μg / mL, the minimum antibacterial concentration (MIC) based on *Bacillus subtilis* is ≤10 μg / mL, and the minimum antibacterial concentration (MIC) based on *Corynebacterium circumferentiale* is ≤10 μg / mL.

[0013] The present invention provides a method for preparing a La / Cu dual-atom nano-bacterial material, which is achieved through the following technical solution: A method for preparing a La / Cu diatomic nanomaterial for sterilization includes the following steps: Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve water-soluble lanthanum salt in deionized water and mix well to obtain a water-soluble lanthanum salt aqueous solution with a concentration of 20~200mg / mL, for later use; Preparation of water-soluble copper salt aqueous solution: Dissolve the water-soluble copper salt in deionized water and mix well to obtain a water-soluble copper salt aqueous solution with a concentration of 20~200mg / mL for later use; Step 2: Disperse calcium carbonate powder in deionized water and stir to form a calcium carbonate suspension with a concentration of 20~100mg / mL. While stirring continuously, add water-soluble lanthanum salt aqueous solution and water-soluble copper salt aqueous solution dropwise to the calcium carbonate suspension. After the addition is completed, stir continuously at room temperature for 12~30 hours. Step 3: Centrifuge the reaction mixture from Step 2, collect the precipitate, dry the precipitate at 80~100℃ for 2~10 hours, and then ball mill and sieve to obtain the La / Cu biatomic nano-sterilizing material.

[0014] Preferably, the water-soluble lanthanum salt in step one is lanthanum nitrate and / or lanthanum chloride.

[0015] Preferably, the water-soluble copper salt in step one is copper nitrate and / or copper chloride.

[0016] Preferably, the mass ratio of lanthanum content in the aqueous solution of water-soluble lanthanum salt added to the calcium carbonate suspension to calcium carbonate content in the calcium carbonate suspension is (1-8):100.

[0017] Preferably, the copper content in the aqueous solution of the water-soluble copper salt added to the calcium carbonate suspension is in a mass ratio of (1-15):100 to the calcium carbonate in the calcium carbonate suspension.

[0018] The above-mentioned method for preparing La / Cu biatomic nano-sterilizing materials can achieve uniform dispersion of single-atom La and single-atom Cu on the surface of calcium carbonate carrier without calcination. The atomic-level dispersion maximizes the metal utilization rate. By utilizing the asymmetric distribution of Cu induced by La, the targeting effect on bacterial cell membrane is enhanced, achieving efficient sterilization under low load. At the same time, without the need for calcination, production efficiency is improved and production energy consumption and costs are reduced.

[0019] Preferably, the loading of single-atom Cu in the La / Cu diatomic nano-bactericidal material is 1 wt%, and the loading of single-atom La is 15 wt%. Then, the minimum antibacterial concentration (MIC) of the La / Cu diatomic nano-bactericidal material based on Ralstonia solanacearum is ≤0.20 μg / mL, the minimum antibacterial concentration (MIC) based on Bacillus thuringiensis is ≤0.20 μg / mL, the minimum antibacterial concentration (MIC) based on Ralstonia solanacearum is ≤0.25 μg / mL, and the minimum antibacterial concentration (MIC) based on Bacillus is ≤0.20 μg / mL.

[0020] Preferably, the loading of single-atom Cu in the La / Cu diatomic nano-bactericidal material is 1 wt%, and the loading of single-atom La is 8 wt%. Therefore, the minimum antibacterial concentration (MIC) of the La / Cu diatomic nano-bactericidal material based on *Ralstonia solanacearum* is ≤10 μg / mL, the minimum antibacterial concentration (MIC) based on *Bacillus subtilis* is ≤10 μg / mL, the minimum antibacterial concentration (MIC) based on *Ralstonia solanacearum* is ≤10 μg / mL, the minimum antibacterial concentration (MIC) based on *Bacillus subtilis* is ≤10 μg / mL, and the minimum antibacterial concentration (MIC) based on *Corynebacterium circumferentiale* is ≤10 μg / mL.

[0021] The present invention provides a method for preparing a La / Cu dual-atom nano-bacterial material, which is achieved through the following technical solution: A method for preparing a La / Cu diatomic nanomaterial for sterilization includes the following steps: Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve water-soluble lanthanum salt in deionized water and mix well to obtain a water-soluble lanthanum salt aqueous solution with a concentration of 20~200mg / mL, for later use; Preparation of water-soluble copper salt aqueous solution: Dissolve the water-soluble copper salt in deionized water and mix well to obtain a water-soluble copper salt aqueous solution with a concentration of 20~200mg / mL for later use; Step 2: Disperse calcium carbonate powder in deionized water and stir to form a calcium carbonate suspension with a concentration of 20~100mg / mL. While stirring continuously, add water-soluble lanthanum salt aqueous solution and water-soluble copper salt aqueous solution dropwise to the calcium carbonate suspension. After the addition is completed, stir continuously at room temperature for 12~30 hours. Step 3: Centrifuge the reaction mixture from Step 2, collect the precipitate, dry the precipitate at 80-100℃ for 2-10 hours, and then ball mill and sieve to obtain solid powder. Step four: calcine the solid powder from step three at 200~400℃ for 1.5~3.0 hours, cool, ball mill and sieve to obtain La / Cu diatomic nano-sterilizing material.

[0022] The La / Cu biatomic nano-bacterial material prepared by the above method has a lower minimum antibacterial concentration (MIC).

[0023] Preferably, the water-soluble lanthanum salt in step one is lanthanum nitrate and / or lanthanum chloride.

[0024] Preferably, the water-soluble copper salt in step one is copper nitrate and / or copper chloride.

[0025] Preferably, the mass ratio of lanthanum content in the aqueous solution of water-soluble lanthanum salt added to the calcium carbonate suspension to calcium carbonate content in the calcium carbonate suspension is (1-8):100.

[0026] Preferably, the copper content in the aqueous solution of the water-soluble copper salt added to the calcium carbonate suspension is in a mass ratio of (1-15):100 to the calcium carbonate in the calcium carbonate suspension.

[0027] Preferably, the loading of single-atom Cu in the La / Cu diatomic nano-bactericidal material is 1 wt%, and the loading of single-atom La is 15 wt%. Then, the minimum antibacterial concentration (MIC) of the La / Cu diatomic nano-bactericidal material based on Ralstonia solanacearum is ≤0.10 μg / mL, the minimum antibacterial concentration (MIC) based on Bacillus thuringiensis is ≤0.15 μg / mL, the minimum antibacterial concentration (MIC) based on Ralstonia solanacearum is ≤0.20 μg / mL, and the minimum antibacterial concentration (MIC) based on Bacillus is ≤0.15 μg / mL.

[0028] Preferably, the loading of single-atom Cu in the La / Cu diatomic nano-bactericidal material is 1 wt%, and the loading of single-atom La is 8 wt%. Therefore, the minimum antibacterial concentration (MIC) of the La / Cu diatomic nano-bactericidal material based on *Ralstonia solanacearum* is ≤7 μg / mL, the minimum antibacterial concentration (MIC) based on *Bacillus thuringiensis* is ≤8 μg / mL, the minimum antibacterial concentration (MIC) based on *Ralstonia solanacearum* is ≤10 μg / mL, the minimum antibacterial concentration (MIC) based on *Bacillus* is ≤9.5 μg / mL, and the minimum antibacterial concentration (MIC) based on *Corynebacterium circumferentiale* is ≤8.5 μg / mL.

[0029] In summary, the present invention has the following advantages: 1. Compared with traditional Cu-based bactericidal materials, this invention achieves precise control of Cu valence state through the directional introduction of La and the La / Cu dual-atom synergistic design, significantly increasing the proportion of highly active Cu⁺ and greatly reducing the minimum antibacterial concentration (MIC). That is, under the same Cu loading, the addition of La can effectively reduce the MIC value, effectively reduce the total Cu loading, avoid the risk of soil accumulation caused by high Cu loading, and balance high efficiency and environmental protection.

[0030] 2. This invention can obtain a uniform dispersion of single-atom La and single-atom Cu on the surface of a calcium carbonate carrier without calcination. The atomic-level dispersion maximizes the metal utilization rate. By utilizing the asymmetric distribution of Cu induced by La, the targeting effect on bacterial cell membranes is enhanced, achieving efficient sterilization under low load. At the same time, without the need for calcination, production efficiency is improved and production energy consumption and costs are reduced.

[0031] 3. The synergistic effect of single-atom La and single-atom Cu enhances the targeted adsorption capacity to pathogen cell membranes. At the same time, the bactericidal efficiency is improved through valence state optimization, reducing the total amount of metal used, lowering the cost of agricultural application and environmental impact. It can be adapted to various agricultural scenarios such as soil application and foliar spraying, providing a new technical path for the green prevention and control of bacterial diseases and the efficient and sustainable development of agricultural sterilization technology.

[0032] 4. The La / Cu diatomic calcium carbonate bactericidal material provided by this invention, through the atomic-level synergistic effect and valence state regulation mechanism of La and Cu, has a 2-fold increase in atomic utilization compared to single-metal single-atom materials. Moreover, this material can exert its bactericidal effect without relying on harsh external conditions (such as ultraviolet light or hydrogen peroxide), and its application method is flexible (soil application or foliar spraying), making it suitable for disease control scenarios of various crops such as tobacco, rice, and vegetables.

[0033] 5. The preparation process can also adopt low-temperature calcination, which has low energy consumption and simple operation. Through the dual-atom synergistic mechanism, the atomic utilization rate of La and Cu elements is greatly improved, which can obtain relatively better sterilization performance. At the same time, while ensuring efficient sterilization, the amount of metal used is reduced, which significantly reduces material costs and environmental risks. Attached Figure Description

[0034] Figure 1 These are the XRD patterns of the nano-bactericidal materials in Example 1 and Comparative Examples 1-2.

[0035] Figure 2 This is a high-resolution TEM image of the La / Cu diatomic nano-sterilizing material in Example 1.

[0036] Figure 3 This is the aberration-corrected elemental distribution spectrum of the La / Cu biatomic nano-sterilizing material in Example 1.

[0037] Figure 4 The image shows the Cu element XPS spectra of the nano-sterilizing materials in Example 1 and Comparative Example 1.

[0038] Figure 5 This is a TEM electron microscope image of the damage to Bacillus caused by the La / Cu biatomic nano-sterilizing material in Example 1.

[0039] Figure 6 These are site test diagrams of the nano-bactericidal materials for thiol functional groups in Example 1 and Comparative Examples 1-2.

[0040] Figure 7 These are site test diagrams of the nano-bactericidal materials for phosphate ester functional groups in Examples 1 and Comparative Examples 1-2. Detailed Implementation

[0041] To further understand the inventiveness and technical advancements of this invention, the preferred embodiments of this invention will be discussed in detail below with reference to examples and comparative examples.

[0042] Example: A La / Cu diatomic nano-sterilizing material includes a calcium carbonate carrier and metal single atoms dispersed in the calcium carbonate carrier in the form of single atoms, wherein the metal single atoms are single atoms of La and single atoms of Cu.

[0043] The loading of single-atom La is 1–8 wt%.

[0044] The loading of single-atom Cu is 1–15 wt%.

[0045] The calcium carbonate carrier has a particle size of 50-1000 nm.

[0046] A method A for preparing a La / Cu dual-atom nano-bactericidal material includes the following steps: Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve water-soluble lanthanum salt in deionized water and mix thoroughly. The water-soluble lanthanum salt is lanthanum nitrate and / or lanthanum chloride. Obtain a water-soluble lanthanum salt aqueous solution with a concentration of 20~200 mg / mL for later use. Preparation of water-soluble copper salt aqueous solution: Dissolve the water-soluble copper salt in deionized water and mix thoroughly. The water-soluble copper salt is copper nitrate and / or copper chloride. Obtain a water-soluble copper salt aqueous solution with a concentration of 20~200 mg / mL for later use. Step 2: Disperse calcium carbonate powder in deionized water and stir to form a calcium carbonate suspension with a concentration of 20-100 mg / mL. While continuously stirring, add water-soluble lanthanum salt aqueous solution and water-soluble copper salt aqueous solution dropwise to the calcium carbonate suspension. The mass ratio of lanthanum content in the water-soluble lanthanum salt aqueous solution to calcium carbonate in the calcium carbonate suspension is (1-8):100; the mass ratio of copper content in the water-soluble copper salt aqueous solution to calcium carbonate in the calcium carbonate suspension is (1-15):100. After the addition is completed, stir continuously at room temperature for 12-30 hours. Step 3: Centrifuge the reaction mixture from Step 2, collect the precipitate, dry the precipitate at 80-100℃ for 2-10 hours, and then ball mill and sieve to obtain the La / Cu biatomic nano-sterilizing material.

[0047] A method B for preparing a La / Cu diatomic nano-bacterial material includes the following steps: Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve water-soluble lanthanum salt in deionized water and mix thoroughly. The water-soluble lanthanum salt is lanthanum nitrate and / or lanthanum chloride. Obtain a water-soluble lanthanum salt aqueous solution with a concentration of 20~200 mg / mL for later use. Preparation of water-soluble copper salt aqueous solution: Dissolve the water-soluble copper salt in deionized water and mix thoroughly. The water-soluble copper salt is copper nitrate and / or copper chloride. Obtain a water-soluble copper salt aqueous solution with a concentration of 20~200 mg / mL for later use. Step 2: Disperse calcium carbonate powder in deionized water and stir to form a calcium carbonate suspension with a concentration of 20-100 mg / mL. While continuously stirring, add water-soluble lanthanum salt aqueous solution and water-soluble copper salt aqueous solution dropwise to the calcium carbonate suspension. The mass ratio of lanthanum content in the water-soluble lanthanum salt aqueous solution to calcium carbonate in the calcium carbonate suspension is (1-8):100; the mass ratio of copper content in the water-soluble copper salt aqueous solution to calcium carbonate in the calcium carbonate suspension is (1-15):100. After the addition is completed, stir continuously at room temperature for 12-30 hours. Step 3: Centrifuge the reaction mixture from Step 2, collect the precipitate, dry the precipitate at 80-100℃ for 2-10 hours, and then ball mill and sieve to obtain solid powder. Step four: calcine the solid powder from step three at 200~400℃ for 1.5~3.0 hours, cool, ball mill and sieve to obtain La / Cu diatomic nano-sterilizing material.

[0048] Example 1: A La / Cu biatomic nano-sterilizing material includes a calcium carbonate carrier with an average particle size of 500 nm and metal single atoms dispersed in the calcium carbonate carrier in the form of single atoms. The metal single atoms are single atoms of La and single atoms of Cu, with the loading of single atoms of La being 4 wt% and the loading of single atoms of Cu being 5 wt%.

[0049] A method for preparing a La / Cu diatomic nanomaterial for sterilization includes the following steps: Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve lanthanum(III) hexahydrate in deionized water and mix thoroughly to obtain a lanthanum nitrate aqueous solution with a concentration of 100 mg / mL for later use; Preparation of water-soluble copper salt aqueous solution: Dissolve copper nitrate in deionized water and mix well to obtain a copper nitrate aqueous solution with a concentration of 100 mg / mL for later use; Step 2: Disperse 5g of calcium carbonate powder in 100mL of deionized water and stir at 500rpm to form a calcium carbonate suspension with a concentration of 50mg / mL. While stirring continuously at 500rpm, add 2.0mL of lanthanum nitrate aqueous solution with a concentration of 100mg / mL from Step 1 and 2.5mL of copper nitrate aqueous solution with a concentration of 100mg / mL from Step 1 dropwise to the calcium carbonate suspension. After the addition is completed, stir at 500rpm for 24 hours at room temperature. Step 3: Centrifuge the reaction mixture from Step 2 at 3000 r / min for 10 minutes, collect the precipitate, dry the precipitate at 80℃ for 2 hours, and then ball mill and sieve to obtain the La / Cu biatomic nano-sterilizing material.

[0050] The difference between Example 2 and Example 1 is as follows: In step three, the reaction mixture in step two is centrifuged at 3000 r / min for 10 minutes, the precipitate is collected, and the precipitate is dried at 80°C for 2 hours. After ball milling and sieving, a solid powder is obtained. In step four, the solid powder in step three is transferred to a ceramic boat, which is placed in a muffle furnace and heated to 250°C at a heating rate of 5°C / min in an air atmosphere. The temperature is maintained for 2 hours, and the mixture is naturally cooled to room temperature. After ball milling and sieving, the La / Cu diatomic nano-sterilizing material is obtained. The remaining steps are the same.

[0051] The difference between Example 3 and Example 1 is that the loading of single-atom La in the La / Cu diatomic nano-sterilizing material is 1 wt%, and the loading of single-atom Cu is 15 wt%.

[0052] A method for preparing a La / Cu diatomic nanomaterial for sterilization includes the following steps: Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve lanthanum(III) hexahydrate in deionized water and mix thoroughly to obtain a lanthanum nitrate aqueous solution with a concentration of 100 mg / mL for later use; Preparation of water-soluble copper salt aqueous solution: Dissolve copper nitrate in deionized water and mix well to obtain a copper nitrate aqueous solution with a concentration of 100 mg / mL for later use; Step 2: Disperse 5g of calcium carbonate powder in 100mL of deionized water and stir at 500rpm to form a calcium carbonate suspension with a concentration of 50mg / mL. While stirring continuously at 500rpm, add 0.5mL of lanthanum nitrate aqueous solution with a concentration of 100mg / mL from Step 1 and 7.5mL of copper nitrate aqueous solution with a concentration of 100mg / mL from Step 1 dropwise to the calcium carbonate suspension. After the addition is completed, stir at 500rpm for 24 hours at room temperature. Step 3: Centrifuge the reaction mixture from Step 2 at 3000 r / min for 10 minutes, collect the precipitate, dry the precipitate at 80℃ for 2 hours, and then ball mill and sieve to obtain the La / Cu biatomic nano-sterilizing material.

[0053] The difference between Example 4 and Example 3 is as follows: In step three, the reaction mixture in step two is centrifuged at 3000 r / min for 10 minutes, the precipitate is collected, and the precipitate is dried at 80°C for 2 hours. After ball milling and sieving, a solid powder is obtained. In step four, the solid powder in step three is transferred to a ceramic boat, which is placed in a muffle furnace and heated to 400°C at a heating rate of 5°C / min in an air atmosphere. The temperature is maintained for calcination for 1.5 hours, and then naturally cooled to room temperature. After ball milling and sieving, the La / Cu diatomic nano-sterilizing material is obtained. The remaining steps are the same.

[0054] The difference between Example 5 and Example 1 is that the loading of single-atom La in the La / Cu diatomic nano-sterilizing material is 3wt%, and the loading of single-atom Cu is 8wt%.

[0055] A method for preparing a La / Cu diatomic nanomaterial for sterilization includes the following steps: Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve lanthanum(III) hexahydrate in deionized water and mix thoroughly to obtain a lanthanum nitrate aqueous solution with a concentration of 100 mg / mL for later use; Preparation of water-soluble copper salt aqueous solution: Dissolve copper nitrate in deionized water and mix well to obtain a copper nitrate aqueous solution with a concentration of 100 mg / mL for later use; Step 2: Disperse 5g of calcium carbonate powder in 100mL of deionized water and stir at 500rpm to form a calcium carbonate suspension with a concentration of 50mg / mL. While stirring continuously at 500rpm, add 1.5mL of lanthanum nitrate aqueous solution with a concentration of 100mg / mL from Step 1 and 4.0mL of copper nitrate aqueous solution with a concentration of 100mg / mL from Step 1 dropwise to the calcium carbonate suspension. After the addition is completed, stir at 500rpm for 24 hours at room temperature. Step 3: Centrifuge the reaction mixture from Step 2 at 3000 r / min for 10 minutes, collect the precipitate, dry the precipitate at 80℃ for 2 hours, and then ball mill and sieve to obtain the La / Cu biatomic nano-sterilizing material.

[0056] The difference between Example 6 and Example 5 is as follows: In step three, the reaction mixture in step two is centrifuged at 3000 r / min for 10 minutes, the precipitate is collected, and the precipitate is dried at 80°C for 2 hours. After ball milling and sieving, a solid powder is obtained. In step four, the solid powder in step three is transferred to a ceramic boat, which is placed in a muffle furnace and heated to 200°C at a heating rate of 5°C / min in an air atmosphere. The temperature is maintained for calcination for 2.5 hours, and then naturally cooled to room temperature. After ball milling and sieving, the La / Cu diatomic nano-sterilizing material is obtained. The remaining steps are the same.

[0057] The difference between Example 7 and Example 1 is that the loading of single-atom La in the La / Cu diatomic nano-sterilizing material is 6 wt%, and the loading of single-atom Cu is 10 wt%.

[0058] A method for preparing a La / Cu diatomic nanomaterial for sterilization includes the following steps: Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve lanthanum chloride in deionized water and mix thoroughly to obtain a lanthanum chloride aqueous solution with a concentration of 100 mg / mL, for later use; Preparation of water-soluble copper salt aqueous solution: Dissolve copper chloride in deionized water and mix well to obtain a copper chloride salt aqueous solution with a concentration of 100 mg / mL for later use; Step 2: Disperse 5g of calcium carbonate powder in 100mL of deionized water and stir at 500rpm to form a calcium carbonate suspension with a concentration of 50mg / mL. While stirring continuously at 500rpm, add 3.0mL of lanthanum nitrate aqueous solution with a concentration of 100mg / mL from Step 1 and 5.0mL of copper nitrate aqueous solution with a concentration of 100mg / mL from Step 1 dropwise to the calcium carbonate suspension. After the addition is completed, stir at 500rpm for 24 hours at room temperature. Step 3: Centrifuge the reaction mixture from Step 2 at 3500 r / min for 10 minutes, collect the precipitate, dry the precipitate at 80℃ for 10 hours, and then ball mill and sieve to obtain the La / Cu biatomic nano-sterilizing material.

[0059] The difference between Example 8 and Example 7 is as follows: In step three, the reaction mixture in step two is centrifuged at 3500 r / min for 10 minutes, the precipitate is collected, and the precipitate is dried at 80°C for 10 hours. After ball milling and sieving, a solid powder is obtained. In step four, the solid powder in step three is transferred to a ceramic boat, which is placed in a muffle furnace and heated to 300°C at a heating rate of 5°C / min in an air atmosphere. The temperature is maintained for calcination for 2.5 hours, and then naturally cooled to room temperature. After ball milling and sieving, the La / Cu diatomic nano-sterilizing material is obtained. The remaining steps are the same.

[0060] Comparative Example 1: A Cu single-atom nano-sterilizing material includes a calcium carbonate carrier with an average particle size of 500 nm and single-atom Cu dispersed in the calcium carbonate carrier in the form of single atoms, with a single-atom Cu content of 5.0 wt%.

[0061] A method for preparing Cu single-atom nano-bacterial material includes the following steps: Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve lanthanum(III) hexahydrate in deionized water and mix thoroughly to obtain a lanthanum nitrate aqueous solution with a concentration of 100 mg / mL for later use; Step 2: Disperse 5g of calcium carbonate powder in 100mL of deionized water and stir at 500rpm to form a calcium carbonate suspension with a concentration of 50mg / mL. While stirring continuously at 500rpm, add 2.5mL of copper nitrate aqueous solution with a concentration of 100mg / mL from Step 1 dropwise to the calcium carbonate suspension. After the addition is completed, stir at 500rpm for 24 hours at room temperature. Step 3: Centrifuge the reaction mixture from Step 2 at 3000 r / min for 10 minutes, collect the precipitate, dry the precipitate at 80℃ for 2 hours, and then ball mill and sieve to obtain Cu single-atom nano-sterilizing material.

[0062] The difference between Comparative Example 2 and Example 1 is as follows: In step three, the reaction mixture in step two is centrifuged at 3000 r / min for 10 minutes, the precipitate is collected, and the precipitate is dried at 80°C for 2 hours. After ball milling and sieving, a solid powder is obtained. In step four, the solid powder in step three is transferred to a ceramic boat, which is placed in a muffle furnace and heated to 250°C at a heating rate of 5°C / min in an air atmosphere. The temperature is maintained for calcination for 2 hours, and the powder is naturally cooled to room temperature. After ball milling and sieving, Cu single-atom nano-sterilizing material is obtained. The remaining steps are the same.

[0063] Comparative Example 3: A La single-atom nano-sterilizing material includes a calcium carbonate carrier with an average particle size of 500 nm and single-atom La dispersed in the calcium carbonate carrier in the form of single atoms, with a single-atom La content of 5.0 wt%.

[0064] A method for preparing Cu single-atom nano-bacterial material includes the following steps: Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve lanthanum(III) hexahydrate in deionized water and mix thoroughly to obtain a lanthanum nitrate aqueous solution with a concentration of 100 mg / mL for later use; Step 2: Disperse 5g of calcium carbonate powder in 100mL of deionized water and stir at 500rpm to form a calcium carbonate suspension with a concentration of 50mg / mL. While stirring continuously at 500rpm, add 2.5mL of lanthanum nitrate aqueous solution with a concentration of 100mg / mL from Step 1 dropwise to the calcium carbonate suspension. After the addition is completed, stir at 500rpm for 24 hours at room temperature. Step 3: Centrifuge the reaction mixture from Step 2 at 3000 r / min for 10 minutes, collect the precipitate, dry the precipitate at 80℃ for 2 hours, and then ball mill and sieve to obtain the La single-atom nano-sterilizing material.

[0065] The difference between Comparative Example 4 and Example 3 is as follows: In step three, the reaction mixture in step two is centrifuged at 3000 r / min for 10 minutes, the precipitate is collected, and the precipitate is dried at 80°C for 2 hours. After ball milling and sieving, a solid powder is obtained. In step four, the solid powder in step three is transferred to a ceramic boat, which is placed in a muffle furnace and heated to 250°C at a heating rate of 5°C / min in an air atmosphere. The temperature is maintained for 2 hours, and the mixture is naturally cooled to room temperature. After ball milling and sieving, La single-atom nano-bacterial material is obtained. The remaining steps are the same.

[0066] The difference between Comparative Example 5 and Example 1 is that: a Cu single-atom nano-sterilizing material includes a calcium carbonate carrier with an average particle size of 500 nm and single-atom Cu dispersed in the calcium carbonate carrier in the form of single atoms, with a single-atom Cu content of 9.0 wt%.

[0067] A method for preparing Cu single-atom nano-bacterial material includes the following steps: Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve lanthanum(III) hexahydrate in deionized water and mix thoroughly to obtain a lanthanum nitrate aqueous solution with a concentration of 100 mg / mL for later use; Step 2: Disperse 5g of calcium carbonate powder in 100mL of deionized water and stir at 500rpm to form a calcium carbonate suspension with a concentration of 50mg / mL. While stirring continuously at 500rpm, add 4.5mL of copper nitrate aqueous solution with a concentration of 100mg / mL from Step 1 to the calcium carbonate suspension dropwise. After the addition is completed, stir at 500rpm for 24 hours at room temperature. Step 3: Centrifuge the reaction mixture from Step 2 at 3000 r / min for 10 minutes, collect the precipitate, dry the precipitate at 80℃ for 2 hours, and then ball mill and sieve to obtain Cu single-atom nano-sterilizing material.

[0068] The difference between Comparative Example 6 and Example 5 is as follows: In step three, the reaction mixture in step two is centrifuged at 3000 r / min for 10 minutes, the precipitate is collected, and the precipitate is dried at 80°C for 2 hours. After ball milling and sieving, a solid powder is obtained. In step four, the solid powder in step three is transferred to a ceramic boat, which is placed in a muffle furnace and heated to 250°C at a heating rate of 5°C / min in an air atmosphere. The temperature is maintained for 2 hours, and the powder is naturally cooled to room temperature. After ball milling and sieving, Cu single-atom nano-sterilizing material is obtained. The remaining steps are the same.

[0069] The difference between Comparative Example 7 and Example 3 is that: a Fe / Cu single-atom nano-sterilizing material includes a calcium carbonate carrier with an average particle size of 500 nm and metal single atoms dispersed in the calcium carbonate carrier in the form of single atoms. The metal single atoms are single-atom Fe and single-atom Cu, with the loading of single-atom Fe being 4 wt% and the loading of single-atom Cu being 5 wt%.

[0070] The preparation method of Fe / Cu single-atom nano-sterilizing material includes the following steps:

[0071] Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve ferric nitrate in deionized water and mix thoroughly to obtain a ferric nitrate aqueous solution with a concentration of 100 mg / mL, for later use; Preparation of water-soluble copper salt aqueous solution: Dissolve copper nitrate in deionized water and mix well to obtain a copper nitrate aqueous solution with a concentration of 100 mg / mL for later use; Step 2: Disperse 5g of calcium carbonate powder in 100mL of deionized water and stir at 500rpm to form a calcium carbonate suspension with a concentration of 50mg / mL. While stirring continuously at 500rpm, add 2.0mL of ferric nitrate aqueous solution with a concentration of 100mg / mL from Step 1 and 2.5mL of copper nitrate aqueous solution with a concentration of 100mg / mL from Step 1 dropwise to the calcium carbonate suspension. After the addition is completed, stir at 500rpm for 24 hours at room temperature. Step 3: Centrifuge the reaction mixture from Step 2 at 3000 r / min for 10 minutes, collect the precipitate, dry the precipitate at 80℃ for 2 hours, and then ball mill and sieve to obtain the Fe / Cu biatomic nano-sterilizing material.

[0072] The difference between Comparative Example 8 and Example 3 is as follows: In step three, the reaction mixture in step two is centrifuged at 3000 r / min for 10 minutes, the precipitate is collected, and the precipitate is dried at 80°C for 2 hours. After ball milling and sieving, a solid powder is obtained. In step four, the solid powder in step three is transferred to a ceramic boat, which is placed in a muffle furnace and heated to 250°C at a heating rate of 5°C / min in an air atmosphere. The temperature is maintained for calcination for 2 hours, and the powder is naturally cooled to room temperature. After ball milling and sieving, the Fe / Cu diatomic nano-sterilizing material is obtained. The remaining steps are the same.

[0073] The structures of Example 1 and Comparative Examples 1 and 2 described above were characterized and verified by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and aberration-corrected scanning transmission electron microscopy (AC-HAADF-STEM). Figure 1 The XRD patterns of Example 1, Comparative Example 1 (single Cu), and Comparative Example 2 (single La) are shown. The results indicate that each sample only exhibits the characteristic diffraction peaks of the carrier calcium carbonate (2θ = 29.4°, 43.1°, 47.5°), and no characteristic peaks of La or Cu metal clusters (such as elemental Cu, La₂O₃) or nanoparticles (Cu) were observed. 0 (43.3°, 50.4°; La2O3: 28.2°, 39.5°), indicating that the metal elements did not form agglomerates and existed in a highly dispersed state.

[0074] Figure 2 The high-resolution TEM image of Example 1 shows that no ordered stripes corresponding to the lattice spacing of metal particles or clusters were observed, further confirming the absence of nanoscale agglomeration. Figure 3The aberration-corrected elemental distribution spectrum shows that La and Cu elements are uniformly distributed at single points on the surface of the calcium carbonate support, with no obvious enrichment areas. Combined with the XRD results, it can be determined that La and Cu are both dispersed on the support surface in the form of single atoms, forming a dual single-atom synergistic system.

[0075] Performance testing – Antibacterial test: Ralstonia solanacearum, Bacillus subtilis, Bacillus thuringiensis, and Corynebacterium circumferentiale were used as bacterial strains. The test method was strictly carried out in accordance with the GB / T21866-2008 standard. Bacteria were quantitatively inoculated onto the sample to be tested, and after a certain period of incubation, the number of viable bacteria in the culture was detected, and the minimum antibacterial concentration (MIC) value corresponding to the material was calculated.

[0076] Table 1: Test parameters of nano-bactericidal materials in Examples 1-8 and Comparative Examples 1-8

[0077] After comparing the antibacterial properties (e.g., MIC data) of Examples 1-8 with those of Comparative Examples 1-8, the core mechanism of "La regulating Cu valence state → enhancing targeted adsorption → improving bactericidal efficiency" was explained using characterization data: 1. Verification of price regulation (see...) Figure 4 ) X-ray photoelectron spectroscopy (XPS) analysis further revealed the regulatory effect of the introduction of La on the valence state of Cu: Figure 4 The fine Cu2p spectra of the La / Cu diatomic nano-bacterial material in Example 1 and the Cu monoatomic nano-bacterial material in Comparative Example 1 show that the introduction of La significantly promotes the conversion of Cu²⁺ to highly active Cu⁺, which is a key factor in improving antibacterial efficiency.

[0078] 2. Visualization of the sterilization process (see...) Figure 5 ) In Example 1, the action of the La / Cu diatomic nanomaterial on pathogens was directly observed using transmission electron microscopy (TEM). Figure 5 The image shows a TEM image of Bacillus cells treated with the La / Cu diatomic nano-sterilizing material in Example 1. It can be seen that a large number of material particles are attached to the surface of the bacterial cell membrane, and the cell membrane is obviously ruptured and the contents are leaked out. This confirms that the material achieves sterilization through the direct interaction between the single-atom active center and the cell membrane, without the need for external auxiliary conditions.

[0079] 3. Targeted adsorption mechanism (see...) Figures 6-7 ) To clarify the cooperative adsorption mechanism between La and Cu, a competition experiment with simulants was conducted to verify it. Figure 6The effect of thiol functional group (-SH) mimic (cysteine) on bactericidal performance was investigated. The results showed that after the addition of the thiol mimic, the bactericidal efficiency of Cu single-atom nano-bacterial material in Comparative Example 1 disappeared, indicating that Cu has strong specific adsorption of thiol groups, which are the core sites for direct bactericidal action. Figure 7 The experiment investigated the effect of sodium phosphate (-PO4) analogues on phosphate esters. After its addition, the bactericidal efficiency of the La single-atom nano-bacterial material in Comparative Example 2 disappeared, confirming that La has a stronger adsorption capacity for phosphate esters and can assist the role of Cu by targeting and binding to the cell membrane phospholipid structure.

[0080] The above results indicate that single-atom La and single-atom Cu form a synergistic effect through strong adsorption of -PO4 and -SH groups, respectively, which greatly enhances the efficiency of bacterial cell membrane destruction. This is the core mechanism by which the antibacterial activity of this invention is improved compared with that of single metal materials.

[0081] In summary, compared with traditional Cu-based bactericidal materials, the La / Cu biatomic nano-bacterial material provided in this invention achieves precise control of Cu valence state through the directional introduction of La and the synergistic design of La / Cu biatoms, significantly increasing the proportion of highly active Cu⁺ and greatly reducing the minimum antibacterial concentration (MIC). That is, under the same Cu loading, the addition of La can effectively reduce the MIC value, effectively reduce the total Cu loading, avoid the risk of soil accumulation caused by high Cu loading, and balance high efficiency and environmental protection.

[0082] It should be noted that this specific embodiment is merely an explanation of the technical solution of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A La / Cu diatomic nano-sterilizing material, characterized in that: The La / Cu biatomic nano-sterilizing material includes a calcium carbonate carrier and metal single atoms dispersed in the calcium carbonate carrier in the form of single atoms, wherein the metal single atoms are single atoms of La and single atoms of Cu.

2. The La / Cu diatomic nano-sterilizing material according to claim 1, characterized in that: The loading of the single atom La is 1 to 8 wt%; the loading of the single atom Cu is 1 to 15 wt%.

3. The La / Cu diatomic nano-sterilizing material according to claim 1, characterized in that: The calcium carbonate carrier has a particle size of 50-1000 nm.

4. The La / Cu diatomic nano-sterilizing material according to claim 1, characterized in that: The La / Cu diatomic nano-bacterial materials have the following minimum antibacterial concentrations (MICs): ≤10 μg / mL for Ralstonia solanacearum, ≤10 μg / mL for Bacillus subtilis, ≤10 μg / mL for Ralstonia solanacearum, ≤10 μg / mL for Bacillus subtilis, and ≤10 μg / mL for Corynebacterium circumferentiale.

5. A method for preparing a La / Cu diatomic nano-bacterial material according to any one of claims 1-4, characterized in that: Includes the following steps: Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve water-soluble lanthanum salt in deionized water and mix well to obtain a water-soluble lanthanum salt aqueous solution with a concentration of 20~200mg / mL, for later use; Preparation of water-soluble copper salt aqueous solution: Dissolve the water-soluble copper salt in deionized water and mix well to obtain a water-soluble copper salt aqueous solution with a concentration of 20~200mg / mL for later use; Step 2: Disperse calcium carbonate powder in deionized water and stir to form a calcium carbonate suspension with a concentration of 20~100mg / mL. While stirring continuously, add water-soluble lanthanum salt aqueous solution and water-soluble copper salt aqueous solution dropwise to the calcium carbonate suspension. After the addition is completed, stir continuously at room temperature for 12~30 hours. Step 3: Centrifuge the reaction mixture from Step 2, collect the precipitate, dry the precipitate at 80-100℃ for 2-10 hours, and then ball mill and sieve to obtain the La / Cu biatomic nano-sterilizing material.

6. The preparation method according to claim 5, characterized in that: The water-soluble lanthanum salt in step one is lanthanum nitrate and / or lanthanum chloride; the water-soluble copper salt in step one is copper nitrate and / or copper chloride.

7. The preparation method according to claim 4, characterized in that: The mass ratio of lanthanum content in the aqueous solution of water-soluble lanthanum salt added to the calcium carbonate suspension to that of calcium carbonate suspension is (1-8):100; the mass ratio of copper content in the aqueous solution of water-soluble copper salt added to the calcium carbonate suspension to that of calcium carbonate suspension is (1-15):

100.

8. A method for preparing a La / Cu diatomic nano-bacterial material according to any one of claims 1-4, characterized in that: Includes the following steps: Step 1, Preparation of water-soluble lanthanum salt aqueous solution: Dissolve water-soluble lanthanum salt in deionized water and mix well to obtain a water-soluble lanthanum salt aqueous solution with a concentration of 20~200mg / mL, for later use; Step 2: Disperse calcium carbonate powder in deionized water and stir to form a calcium carbonate suspension with a concentration of 20~100mg / mL. While stirring continuously, add water-soluble lanthanum salt aqueous solution and water-soluble copper salt aqueous solution dropwise to the calcium carbonate suspension. After the addition is completed, stir continuously at room temperature for 12~30 hours. Step 3: Centrifuge the reaction mixture from Step 2, collect the precipitate, dry the precipitate at 80-100℃ for 2-10 hours, and then ball mill and sieve to obtain solid powder. Step four: calcine the solid powder from step three at 200~400℃ for 1.5~3.0 hours, cool, ball mill and sieve to obtain La / Cu diatomic nano-sterilizing material.

9. The preparation method according to claim 8, characterized in that: The water-soluble lanthanum salt in step one is lanthanum nitrate and / or lanthanum chloride; the water-soluble copper salt in step one is copper nitrate and / or copper chloride.

10. The preparation method according to claim 8, characterized in that: The mass ratio of lanthanum content in the aqueous solution of water-soluble lanthanum salt added to the calcium carbonate suspension to that of calcium carbonate suspension is (1-8):100; the mass ratio of copper content in the aqueous solution of water-soluble copper salt added to the calcium carbonate suspension to that of calcium carbonate suspension is (1-15):100.

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