Porous co-doped cofe cumn ni-lDH nanomaterials, methods of making and applications thereof

Abstract

The application discloses a five-element co-doped porous CoFeCuMnNi-LDH nanomaterial and a preparation method and application thereof, and relates to the technical field of functional nanomaterials. In the application, cobalt salt, iron salt, copper salt, manganese salt and nickel salt are prepared into a multi-element metal salt precursor solution according to a proportioning ratio, an alkaline solution of NaOH and Na2CO3 is compounded, a target material is prepared through water bath mixing, microwave-hydrothermal combined reaction, and combination of chitosan quaternary ammonium salt modification and freeze drying. The material has a two-dimensional layered porous structure, excellent photocatalytic and peroxidase-like activities, and can efficiently produce reactive oxygen free radicals. The material is synergistically bactericidal with the quaternary ammonium salt, has high efficiency, and has a simple, environment-friendly and easy industrialization preparation process.

Description

Technical Field

[0001] This invention relates to the field of functional nanomaterials technology, specifically to pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterials, their preparation methods, and applications. Background Technology

[0002] In the process of global public health development, the continuous proliferation and widespread spread of multidrug-resistant bacteria has become a critical problem that urgently needs to be solved. Traditional antibiotics, due to their single mechanism of action, are easily overcome by drug-resistant strains, which not only leads to a significant decline in antibacterial efficacy, but also increases the difficulty of clinical infection treatment and intensifies the consumption of medical resources. Developing new antibacterial strategies with high efficiency, non-drug resistance, and environmentally friendly characteristics has become a research hotspot in the fields of biomedicine and materials.

[0003] Photocatalytic antibacterial and nanozyme antibacterial technologies, with their non-specific antibacterial mechanisms, can disrupt key biological structures of bacteria, such as cell membranes, nucleic acids, and proteins, by catalytically generating reactive oxygen species (ROS), thus preventing the development of drug resistance at its source and becoming an important development direction for replacing traditional antibiotics. Layered double hydroxide (LDH), as a typical two-dimensional layered anionic clay material, has advantages such as tunable metal element composition, regular layered structure, abundant surface active sites, good biocompatibility, and controllable preparation cost. It is widely used in the construction of functional materials such as photocatalysis and enzyme catalysis, and is an ideal matrix for developing novel antibacterial materials.

[0004] Cobalt-iron bimetallic layered double hydroxides (CoFe-LDH), relying on the synergistic effect of Co and Fe metals, exhibit excellent photocatalytic performance and peroxidase-like activity. They can catalyze the generation of reactive oxygen species (ROS) under light and mild conditions to achieve antibacterial effects, making them a core research direction for LDH-based antibacterial materials. However, existing CoFe-LDH preparation technologies still have many shortcomings. Their electron-hole recombination rate is relatively fast, and the exposure of catalytic active sites is insufficient, resulting in limited ROS generation and antibacterial efficiency and sustained antibacterial ability that cannot meet practical application requirements. Furthermore, traditional CoFe-LDH preparation processes also suffer from difficulties in controlling crystallinity, irregular interlayer structures, and poor porosity, further restricting their catalytic performance and antibacterial effects.

[0005] Furthermore, single catalytic antibacterial mechanisms are insufficient for achieving efficient synergistic sterilization, and some modification processes are complex and environmentally unfriendly, hindering industrial-scale production. Therefore, how to enhance the catalytic activity and porous structure of LDH-based materials through process optimization and structural control, achieving efficient synergy between photocatalysis and nanozyme catalysis, and ultimately developing highly efficient and easily prepared LDH-based antibacterial nanomaterials, has become a pressing technical challenge in this field. Summary of the Invention

[0006] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide a five-element co-doped porous CoFeCuMnNi-LDH nanomaterial, its preparation method and application. By introducing Cu ions, the electron migration and catalytic activity are enhanced, thereby improving the synergistic antibacterial ability. The material has a two-dimensional layered structure and can generate active oxygen species under light irradiation to achieve rapid and efficient sterilization.

[0007] The technical solution of this invention is as follows:

[0008] In a first aspect, the present invention provides a method for preparing pentagonally co-doped porous CoFeCuMnNi-LDH nanomaterials, comprising the following steps:

[0009] S1: Cobalt salt, iron salt, copper salt, manganese salt and nickel salt are dissolved in water in a molar ratio of Co, Fe, Cu and (Mn+Ni) of 3:1:(0.5-3):(0.045-0.05) to obtain a multi-metal salt precursor solution, wherein the molar ratio of Mn to Ni is (0.9-1.1):1;

[0010] S2: Dissolve NaOH and Na2CO3 in water at a mass ratio of 1:(1.25-1.75) to prepare an alkaline solution;

[0011] S3: After mixing the multi-metal salt precursor solution with the alkaline solution evenly, mix in a water bath at 37-39℃ for 15-30 minutes, then react in a microwave environment at 50-60℃ for 1-2 hours; then raise the temperature to 80-90℃ and react hydrothermally for 2-4 hours.

[0012] S4: After the hydrothermal reaction is completed, the mixture is cooled to room temperature, filtered, washed, and then the washed precipitate is dispersed in an ethanol solution containing 0.5-1 wt.% chitosan quaternary ammonium salt (HTCC) and then freeze-dried to obtain pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterials.

[0013] Preferably, in step S1, the cobalt salt is Co(NO3)2·6H2O, the iron salt is Fe(NO3)3·9H2O, the copper salt is CuCl2·2H2O, the manganese salt is Mn(NO3)2·4H2O, and the nickel salt is NiSO4·6H2O.

[0014] Preferably, in step S1, the molar concentration of iron ions in the multi-metal salt precursor solution is 0.14-0.15 mol / L.

[0015] Preferably, in step S2, the total concentration of NaOH and Na2CO3 in the alkaline solution is 3-3.2 mol / L.

[0016] Preferably, in step S3, the volume ratio of the multi-metal salt precursor solution to the alkaline solution is 1:(0.9-1.1).

[0017] Preferably, in step S4, the chitosan quaternary ammonium salt is 2-hydroxypropyltrimethylammonium chloride chitosan (HTCC).

[0018] Secondly, the present invention provides a pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterial, which is prepared by the above-mentioned method for preparing pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterial.

[0019] Preferably, the pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterial has a two-dimensional layered structure.

[0020] Thirdly, the present invention provides the application of the above-mentioned pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterial, which is used for sterilization.

[0021] This invention successfully prepared pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterials through a microwave-hydrothermal combined process with freeze-drying modification. Compared with existing technologies, this invention exhibits significant advantages in material structure, preparation process, antibacterial properties, and practical application value. Specific beneficial effects are as follows:

[0022] 1. This invention precisely controls the molar ratio of Co, Fe, Cu, Mn, and Ni, utilizing the complementary electronic orbitals of multiple transition metals to effectively reduce the recombination rate of electron-hole pairs within the material, significantly optimizing charge transfer efficiency and greatly enhancing the material's photocatalytic activity and peroxidase-like activity. Under light and mild conditions, the material can efficiently catalyze the generation of various ROS such as ·OH and carbonate radicals, achieving multi-target oxidative destruction of bacteria. Compared to traditional bimetallic LDH materials, the amount of ROS generated is significantly increased, providing a core driving force for efficient sterilization.

[0023] 2. This invention utilizes a microwave-hydrothermal combined preparation process, along with the modification effect of chitosan quaternary ammonium salt, to form a regular two-dimensional layered porous structure in the prepared CoFeCuMnNi-LDH nanomaterials. This structure not only significantly increases the specific surface area of ​​the material, fully exposing catalytic active sites and improving the contact efficiency with the substrate, but also provides ample channels for the generation and diffusion of ROS, further enhancing the catalytic and antibacterial properties of the material. Simultaneously, the regular layered stacked structure improves the crystallinity of the material, significantly enhancing its structural stability.

[0024] 3. This invention employs an alkaline system composed of NaOH and Na2CO3 to achieve synergistic and long-lasting ROS generation: NaOH provides a strongly alkaline environment, rapidly promoting the decomposition of peroxides and the hydrolysis and activation of metal ions, generating short-lived, strongly oxidizing ROS such as ·OH, thus achieving rapid sterilization; Na2CO3, as a weakly alkaline buffer, can maintain the pH stability of the reaction system, avoiding material structure damage due to excessive alkalinity, while simultaneously converting ·OH into long-lasting carbonate free radicals, extending the antibacterial action time, thus achieving a combination of rapid sterilization and long-lasting bacteriostasis.

[0025] 4. In this invention, the washed precipitate is dispersed in a chitosan quaternary ammonium salt ethanol solution and then freeze-dried. The chitosan quaternary ammonium salt is firmly attached to the material surface through hydrogen bonding. On the one hand, its quaternary ammonium salt groups can destroy bacterial cell membranes through electrostatic interaction, achieving physical sterilization, which forms a synergistic effect with the oxidative sterilization of ROS, greatly improving the overall sterilization efficiency. On the other hand, the introduction of chitosan quaternary ammonium salt significantly improves the biocompatibility of the material and reduces its cytotoxicity, laying the foundation for its practical application in biomedicine and other fields.

[0026] 5. The microwave-hydrothermal combined process employed in this invention enables rapid and uniform reaction of raw materials during the microwave stage, while the hydrothermal stage further promotes crystal growth and structural regularization. Compared to the traditional single hydrothermal method, the reaction efficiency is significantly improved, and the reaction conditions are mild, requiring no high temperature or high pressure. Furthermore, the entire preparation process uses water and ethanol as solvents, with no toxic or harmful reagents involved, making it environmentally friendly. The freeze-drying process avoids the collapse of the material's pore structure and the deactivation of active sites caused by traditional drying methods, further ensuring material performance. The preparation method of this invention is simple, convenient to operate, and uses readily available raw materials, enabling industrial-scale production and possessing excellent industrialization prospects.

[0027] 6. The CoFeCuMnNi-LDH nanomaterials prepared in this invention rely on a dual non-specific antibacterial mechanism of ROS oxidation and physical destruction by quaternary ammonium salts. They act on multiple key structures of bacteria, such as cell membranes, nucleic acids, and proteins, making it difficult for bacteria to develop drug resistance through gene mutations. Compared with traditional antibiotics, they have significant advantages in dealing with multidrug-resistant bacteria, providing a new and effective way to solve the public health problems caused by multidrug-resistant bacteria.

[0028] In summary, the CoFeCuMnNi-LDH nanomaterials prepared by this invention possess high catalytic activity, excellent antibacterial properties, and good biocompatibility. Furthermore, the preparation process is highly efficient, environmentally friendly, and easy to industrialize, showing broad application prospects in various practical scenarios requiring sterilization and disinfection, such as medical and health care, food processing, and environmental disinfection. Attached Figure Description

[0029] Figure 1The powder X-ray diffraction pattern of the porous CoFeCuMnNi-LDH nanomaterial prepared in Example 1 of this invention.

[0030] Figure 2 The transmission electron microscope (TEM) image of the porous CoFeCuMnNi-LDH nanomaterial prepared in Example 1 of this invention.

[0031] Figure 3 The absorbance test results are for the nanomaterials prepared in Examples 1-4 and Comparative Examples 1-7 of this invention.

[0032] Figure 4 The results show the degradation rate of Rhodamine B by the nanomaterials prepared in Examples 1-4 and Comparative Examples 1-7 of this invention.

[0033] Figure 5 The results show the bactericidal efficiency test results of the nanomaterials prepared in Examples 1-4 and Comparative Examples 1-7 of this invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0035] Example 1

[0036] The preparation method of the five-element co-doped porous CoFeCuMnNi-LDH nanomaterial in this embodiment includes the following steps:

[0037] S1: Weigh 0.45g Co(NO3)2·6H2O, 0.21g Fe(NO3)3·9H2O, 0.044g CuCl2·2H2O, 0.0032g Mn(NO3)2·4H2O and 0.00335g NiSO4·6H2O, dissolve them in 3.5mL of deionized water to prepare a homogeneous multi-metal salt precursor solution.

[0038] S2: Dissolve 0.27g NaOH and 0.4g Na2CO3 in 3.5mL of deionized water to prepare an alkaline solution.

[0039] S3: Mix 3.5 mL of multi-metal salt precursor solution and 3.5 mL of alkaline solution evenly under stirring, mix in a water bath at 37 °C for 30 min, then transfer to a microwave synthesis apparatus and react at 50 °C in a microwave environment for 1 h; then raise the temperature to 80 °C and hydrothermally react for 2 h.

[0040] S4: After the hydrothermal reaction was completed, the product was cooled to room temperature, filtered, and washed successively with deionized water and anhydrous ethanol. The washed precipitate was then dispersed in an ethanol solution containing 0.5 wt.% HTCC, ultrasonically dispersed for 30 min, and then freeze-dried to obtain pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterials.

[0041] Example 2

[0042] The preparation method of the five-element co-doped porous CoFeCuMnNi-LDH nanomaterial in this embodiment includes the following steps:

[0043] S1: Weigh 0.45g Co(NO3)2·6H2O, 0.21g Fe(NO3)3·9H2O, 0.088g CuCl2·2H2O, 0.0032g Mn(NO3)2·4H2O and 0.00335g NiSO4·6H2O, dissolve them in 3.5mL of deionized water to prepare a homogeneous multi-metal salt precursor solution.

[0044] S2: Dissolve 0.27g NaOH and 0.4g Na2CO3 in 3.5mL of deionized water to prepare an alkaline solution.

[0045] S3: Mix 3.5 mL of multi-metal salt precursor solution and 3.5 mL of alkaline solution evenly under stirring, mix in a water bath at 38 °C for 30 min, then transfer to a microwave synthesis apparatus and react at 55 °C in a microwave environment for 1.5 h; then raise the temperature to 85 °C and hydrothermally react for 3 h.

[0046] S4: After the hydrothermal reaction was completed, the product was cooled to room temperature, filtered, and washed successively with deionized water and anhydrous ethanol. The washed precipitate was then dispersed in an ethanol solution containing 0.75 wt.% HTCC, ultrasonically dispersed for 30 min, and then freeze-dried to obtain pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterials.

[0047] Example 3

[0048] The preparation method of the five-element co-doped porous CoFeCuMnNi-LDH nanomaterial in this embodiment includes the following steps:

[0049] S1: Weigh 0.45g Co(NO3)2·6H2O, 0.21g Fe(NO3)3·9H2O, 0.167g CuCl2·2H2O, 0.0032g Mn(NO3)2·4H2O and 0.00335g NiSO4·6H2O, dissolve them in 3.5mL of deionized water to prepare a homogeneous multi-metal salt precursor solution.

[0050] S2: Dissolve 0.27g NaOH and 0.4g Na2CO3 in 3.5mL of deionized water to prepare an alkaline solution.

[0051] S3: Mix 3.5 mL of multi-metal salt precursor solution and 3.5 mL of alkaline solution evenly under stirring, mix in a 39 °C water bath for 15 min, then transfer to a microwave synthesis apparatus and react in a 58 °C microwave environment for 100 min; then raise the temperature to 88 °C and hydrothermally react for 3.5 h.

[0052] S4: After the hydrothermal reaction was completed, the product was cooled to room temperature, filtered, and washed successively with deionized water and anhydrous ethanol. The washed precipitate was then dispersed in an ethanol solution containing 0.8 wt.% HTCC, ultrasonically dispersed for 30 min, and then freeze-dried to obtain pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterials.

[0053] Example 4

[0054] The preparation method of the five-element co-doped porous CoFeCuMnNi-LDH nanomaterial in this embodiment includes the following steps:

[0055] S1: Weigh 0.45g Co(NO3)2·6H2O, 0.21g Fe(NO3)3·9H2O, 0.264g CuCl2·2H2O, 0.0032g Mn(NO3)2·4H2O and 0.00335g NiSO4·6H2O, dissolve them in 3.5mL of deionized water to prepare a homogeneous multi-metal salt precursor solution.

[0056] S2: Dissolve 0.27g NaOH and 0.4g Na2CO3 in 3.5mL of deionized water to prepare an alkaline solution.

[0057] S3: Mix 3.5 mL of multi-metal salt precursor solution and 3.5 mL of alkaline solution evenly under stirring, mix in a water bath at 37 °C for 20 min, then transfer to a microwave synthesis apparatus and react at 60 °C in a microwave environment for 2 h; then raise the temperature to 90 °C and hydrothermally react for 4 h.

[0058] S4: After the hydrothermal reaction was completed, the product was cooled to room temperature, filtered, and washed successively with deionized water and anhydrous ethanol. The washed precipitate was then dispersed in an ethanol solution containing 1 wt.% HTCC, ultrasonically dispersed for 30 min, and then freeze-dried to obtain pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterials.

[0059] Comparative Example 1

[0060] The difference from Example 1 is that CuCl2·2H2O is not added in step S1. The final product obtained is porous CoFe-LDH nanomaterials.

[0061] Comparative Example 2

[0062] The difference from Example 2 is that Na2CO3 is not added in step S2.

[0063] Comparative Example 3

[0064] The difference from Example 3 is that in step S3, the reaction temperature under microwave environment is 25°C.

[0065] Comparative Example 4

[0066] The difference from Example 4 is that in step S4, the washed precipitate is directly dried to obtain the final product CoFeCuMnNi-LDH nanomaterials.

[0067] Comparative Example 5

[0068] The difference from Example 1 is that Mn(NO3)2·4H2O is not added in step S1.

[0069] Comparative Example 6

[0070] The difference from Example 1 is that NiSO4·6H2O is not added in step S1.

[0071] Comparative Example 7

[0072] The difference from Example 1 is that in step S3, the reaction is not carried out in a microwave environment, but directly in a hydrothermal reaction for 3 hours.

[0073] The porous CoFeCuMnNi-LDH nanomaterial prepared in Example 1 was subjected to powder X-ray diffraction (XRD) analysis. The results are as follows: Figure 1 As shown in the figure, the porous CoFeCuMnNi-LDH nanomaterial of Example 1 has a typical hydrotalcite structure, and the layered structure is not disrupted by the pentagonal metal doping.

[0074] The porous CoFeCuMnNi-LDH nanomaterials prepared in Example 1 were subjected to transmission electron microscopy (TEM) for analysis. The results are as follows: Figure 2 As shown in the figure, the porous CoFeCuMnNi-LDH nanomaterial exhibits a distinct porous layered structure, which is beneficial for the exposure of reaction sites and the enhancement of activity.

[0075] Eleven samples of nanomaterials prepared in Examples 1-4 and Comparative Examples 1-7 (20 µg each) and 40 mM 3,3',5,5'-tetramethylbenzidine (TMB) were added to 1 mL of acetate-sodium acetate buffer solution (pH 3.6), followed by 10 µL of 1 M H₂O₂ solution, resulting in eleven systems with different nanomaterials. After shaking each system for 1 min, the absorbance was measured at 652 nm using a UV-Vis spectrophotometer. The intensity of the absorbance reflects the peroxidase-like activity of the nanomaterials. The principle is that peroxidase-like activity decomposes H₂O₂ to generate hydroxyl radicals. These hydroxyl radicals react with TMB to produce a blue product with an absorption peak at 652 nm. Therefore, the intensity of the absorption peak at 652 nm indicates the enzyme activity. The results are as follows: Figure 3 As shown, the absorbance of the systems with porous CoFeCuMnNi-LDH nanomaterials added in Examples 1-4 were 0.98, 0.94, 0.97, and 1.08, respectively, while the absorbance of the systems with nanomaterials added in Comparative Examples 1-7 were 0.22, 0.10, 0.15, 0.13, 0.16, 0.14, and 0.11, respectively. The comparison shows that, compared to the comparative examples, the porous CoFeCuMnNi-LDH nanomaterials prepared in the embodiments of this invention exhibit better peroxidase-like activity.

[0076] The nanomaterials prepared in Examples 1-4 and Comparative Examples 1-7 were used to degrade Rhodamine B under visible light. Specifically, a 10 mg / L Rhodamine B solution was prepared, and its absorbance (C0) was measured. 10 mg of the nanomaterial was added to 10 mL of the Rhodamine B solution, followed by light irradiation. Absorbance measurements were taken at degradation times of 0 min, 10 min, 20 min, 30 min, and 40 min to obtain the absorbance (C) of the remaining Rhodamine B solution. t Then the degradation rate = (1-C) t / C0)×100%). The result is as follows: Figure 4 As shown in the figure, compared with the comparative example, the porous CoFeCuMnNi-LDH nanomaterials prepared in the embodiments of the present invention have a significantly higher photodegradation rate and better photocatalytic activity.

[0077] The antibacterial effects of the nanomaterials prepared in Examples 1-4 and Comparative Examples 1-7 were determined using the plate count method. Specifically, Gram-negative Escherichia coli was added to a pH buffer solution to prepare a 1 mL bacterial suspension with a pH of 5.4, containing a bacterial concentration of 102. 6 / mL. Take 11 portions of the above bacterial solution and add 50μL of H2O2 solution (concentration 1mM) to each. Then add 100μg of the nanomaterials from Examples 1-4 and Comparative Examples 1-7 to each of the 11 bacterial solutions to prepare different bacterial solution samples. Shake well and irradiate under simulated sunlight (light intensity 1mW / cm²). 2 After 10 minutes, samples of different bacterial solutions were sequentially plated and counted to obtain the bacterial concentration C after sterilization. Therefore, the sterilization efficiency of the nanomaterial = (1 - C / 10) / (1 - C / 10). 6 () × 100%. Calculations show that the sterilization efficiencies of the nanomaterials in Examples 1-4 are 96%, 95%, 92%, and 92%, respectively, while the sterilization efficiencies of Comparative Examples 1-7 are 34%, 24%, 26%, 18%, 20%, 17%, and 21%, respectively. (Specific details are as follows...) Figure 5 As shown in the figure, the sterilization efficiency of the nanomaterials in Examples 1-4 is all above 90%, while the sterilization efficiency of the nanomaterials in Comparative Examples 1-7 is all below 40%. Therefore, the pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterials prepared in this invention have excellent sterilization effects.

[0078] In summary, the absorbance, photocatalytic activity, and antibacterial effect of the nanomaterials in Examples 1-4 are all superior to those in Comparative Examples 1-7. The reasons are analyzed as follows:

[0079] Cu is the key doping metal in this invention system. It can form a multi-electron synergistic effect with Co and Fe, optimize the electronic and band structures, reduce the electron-hole recombination rate, and significantly improve peroxidase-like activity and ROS generation capacity. Therefore, in Comparative Example 1 without Cu, the prepared nanomaterial is CoFeMnNi-LDH nanomaterial, with significantly weakened electronic control ability and significantly reduced ROS generation. Consequently, the absorbance, photocatalytic oxidation degradation rate of Rhodamine B, and oxidative damage to Escherichia coli are significantly reduced, resulting in lower bactericidal efficiency.

[0080] Na₂CO₃ is not only an alkali source but also a pH buffer and free radical converter. It can convert strong oxidizing ·OH into carbonate free radicals with longer lifespan and longer-lasting effects, achieving a synergistic effect of rapid sterilization and long-lasting antibacterial activity. Therefore, in Comparative Example 2, without the addition of Na₂CO₃ to the alkaline solution, the system's pH fluctuates greatly, the material structure is easily damaged by strong alkali, and long-lasting carbonate free radicals cannot be generated. The total amount and stability of ROS decrease significantly. Consequently, the nanomaterials in Comparative Example 2 have the lowest absorbance, short ROS action time, low utilization rate, poor bactericidal persistence, and a significantly weakened ability to continuously degrade Rhodamine B, with a bactericidal efficiency of only 24%.

[0081] In Comparative Example 3, the microwave reaction temperature was too low, resulting in insufficient crystal nucleus growth, loose and disordered structure, small specific surface area, and insufficient exposure of active sites. This led to a significant reduction in catalytic efficiency and a decrease in ROS generation. Consequently, the absorbance of the prepared nanomaterials was low, the degradation efficiency of Rhodamine B under visible light was significantly reduced, and the oxidative killing ability against bacteria was weak, with a bactericidal efficiency of only 26%.

[0082] In this invention, freeze-drying maintains the layered porous structure of the nanomaterials, ensuring full exposure of active sites. In contrast, Comparative Example 4, using conventional drying methods, easily leads to nanosheet stacking, pore collapse, and encapsulation of active sites, resulting in a significant decrease in specific surface area and mass transfer efficiency, reduced catalytic performance, decreased absorbance of the nanomaterials, a significantly slower degradation rate of Rhodamine B, and a substantial reduction in contact efficiency with bacteria and H2O2, leading to a significant decrease in catalytic and bactericidal capabilities, with a bactericidal efficiency of only 18%.

[0083] As an electronic regulator, Mn can further optimize the electron cloud density of the metal center, promoting electron transfer and enzyme-like catalytic cycling. Therefore, in Comparative Example 5 without Mn, the pentagonal synergy becomes quaternary synergy, the electron complementarity effect is weakened, the charge separation efficiency decreases, the peroxidase-like activity and photocatalytic ROS production capacity decrease, the absorbance of the nanomaterial is significantly reduced, the degradation rate of Rhodamine B decreases, and the bactericidal effect on Escherichia coli is weakened, with a bactericidal efficiency of only 20%.

[0084] Ni doping can stabilize the layered structure of LDH, improve crystallinity, and enhance the conductivity and catalytic cycle stability of the material. Therefore, in Comparative Example 6 without Ni addition, crystal defects increased, structural stability decreased, catalytic active centers were easily deactivated, peroxidase-like activity decreased, ROS generation was insufficient, the absorbance of the nanomaterial decreased significantly, the antibacterial effect was greatly reduced, and the bactericidal efficiency was only 17%. At the same time, the electronic regulation and conductivity between metal centers were weakened, the photogenerated carrier migration efficiency decreased, the catalytic cycle could not be carried out efficiently and continuously, and the degradation rate of Rhodamine B slowed down.

[0085] The microwave stage is responsible for rapidly, uniformly, and gently initiating precursor nucleation, laying the foundation for subsequent hydrothermal growth of high-quality crystals. Therefore, Comparative Example 7 did not undergo the reaction under microwave conditions but instead carried out a direct hydrothermal reaction. This resulted in slow and uneven nucleation, the formation of large aggregates, small specific surface area, few active sites, poor structural regularity, a significant decrease in catalytic performance, a significant reduction in the absorbance of nanomaterials, a significant decrease in the degradation rate of Rhodamine B, and a bactericidal efficiency of only 21%.

[0086] In summary, the pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterials prepared in this invention possess both photocatalytic and peroxidase-like activities, effectively catalyzing the generation of various reactive oxygen species under light irradiation to achieve highly efficient synergistic killing of bacteria. This material exhibits stable structure, a simple preparation method, and is environmentally friendly, demonstrating promising antibacterial application prospects and suitability for various practical scenarios requiring sterilization and disinfection.

Claims

1. The application of pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterials, characterized in that, The five-element co-doped porous CoFeCuMnNi-LDH nanomaterial catalyzes the generation of various reactive oxygen free radicals from hydrogen peroxide under light irradiation, which can be used for sterilization; the preparation method of the five-element co-doped porous CoFeCuMnNi-LDH nanomaterial includes the following steps: S1: Cobalt salt, iron salt, copper salt, manganese salt and nickel salt are dissolved in water in a molar ratio of Co, Fe, Cu and (Mn+Ni) of 3:1:(0.5-3):(0.045-0.05) to obtain a multi-metal salt precursor solution, wherein the molar ratio of Mn to Ni is (0.9-1.1):1; S2: Dissolve NaOH and Na2CO3 in water at a mass ratio of 1:(1.25-1.75) to prepare an alkaline solution; S3: After mixing the multi-metal salt precursor solution with the alkaline solution evenly, mix in a water bath at 37-39℃ for 15-30 minutes, then react in a microwave environment at 50-60℃ for 1-2 hours; then raise the temperature to 80-90℃ and react hydrothermally for 2-4 hours. S4: After the hydrothermal reaction is completed, the mixture is cooled to room temperature, filtered, washed, and then the washed precipitate is dispersed in an ethanol solution containing 0.5-1 wt.% chitosan quaternary ammonium salt, and then freeze-dried to obtain five-component co-doped porous CoFeCuMnNi-LDH nanomaterials; the chitosan quaternary ammonium salt is 2-hydroxypropyltrimethylammonium chloride chitosan.

2. The application of the pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterial as described in claim 1, characterized in that, In step S1, the cobalt salt is Co(NO3)2·6H2O, the iron salt is Fe(NO3)3·9H2O, the copper salt is CuCl2·2H2O, the manganese salt is Mn(NO3)2·4H2O, and the nickel salt is NiSO4·6H2O.

3. The application of the pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterial as described in claim 1, characterized in that, In step S1, the molar concentration of iron ions in the multi-metal salt precursor solution is 0.14-0.15 mol / L.

4. The application of the pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterial as described in claim 3, characterized in that, In step S2, the total concentration of NaOH and Na2CO3 in the alkaline solution is 3-3.2 mol / L.

5. The application of the pentagonal co-doped porous CoFeCuMnNi-LDH nanomaterial as described in claim 4, characterized in that, In step S3, the volume ratio of the multi-metal salt precursor solution to the alkaline solution is 1:(0.9-1.1).

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