Manganese dioxide composite catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of functional composite materials, in particular to a manganese dioxide composite catalyst and a preparation method and application thereof. The manganese dioxide composite catalyst comprises basic MnO2 nanoparticles, a tannic acid surface modification layer coating the surfaces of the basic MnO2 nanoparticles, and functional components loaded through a metal-polyphenol coordination network in the modification layer. The preparation method mainly comprises the following steps: preparing the basic MnO2 nano-particles, dispersing the basic MnO2 nano-particles, reacting the dispersed basic MnO2 nano-particles with a tannic acid solution under an alkaline condition to form the modification layer, and introducing functional components in the reaction process. According to the catalyst, through a stable coordination network constructed by tannic acid, non-dissolution type firm loading of functional components is achieved, the catalyst shows efficient and broad-spectrum antibacterial performance on bacteria and fungi, the metal ion dissolution concentration is extremely low, safety is high, and excellent antibacterial durability can still be kept after multiple times of washing. The catalyst can be applied to preparation of EVA composite foaming antibacterial insoles. The invention provides a solution of an antibacterial material with high efficiency, safety and long-acting characteristics.

Description

Technical Field

[0001] This application relates to the field of functional composite materials technology, and in particular to a manganese dioxide composite catalyst and its application in EVA foam products. Background Technology

[0002] Polymer products (such as shoe insoles) are prone to becoming carriers for microbial growth and transmission during use. Therefore, endowing them with long-lasting, safe, and broad-spectrum antibacterial functions has always been a key focus of the industry. Currently, the mainstream solution is to add inorganic antibacterial agents to the polymer matrix.

[0003] Among them, silver-based antibacterial agents (such as silver-loaded zeolites and nano-silver) are the most widely used. These materials typically rely on silver ions (Ag) for antibacterial activity. + The continuous, slow release of silver ions inhibits microorganisms by disrupting their cell membranes or interfering with their metabolic processes. While this method exhibits high initial antibacterial efficiency, it has several significant limitations: First, the long-term dissolution of silver ions may pose potential risks of bioaccumulation and environmental toxicity, raising safety concerns, particularly in applications involving direct contact with the human body. Second, as the active ingredient is continuously lost, its antibacterial performance inevitably diminishes over time and with use, making it unsuitable for scenarios requiring high durability. Finally, its inhibitory effect on fungi is generally weaker than on bacteria, indicating an insufficiently comprehensive antibacterial spectrum.

[0004] Manganese dioxide, as a low-cost and environmentally compatible transition metal oxide, has attracted attention in the field of antibacterial materials due to its potential to catalyze the generation of reactive oxygen species. However, directly applying conventional manganese dioxide materials to polymer composite systems often faces numerous challenges, such as insufficient antibacterial efficiency, weak bonding with the matrix, and difficulty in maintaining performance. Its actual application effect is far from ideal, especially in the "contact" catalytic antibacterial pathway that does not rely on the dissolution of metal ions. Existing technologies have not yet provided a reliable solution that achieves a good balance between high efficiency, safety, and durability.

[0005] Therefore, developing a novel non-leaching antibacterial material that can avoid the risk of ion leaching while possessing both high efficiency and broad-spectrum antibacterial properties and excellent durability is of great practical significance for improving the functionality and safety of related polymer products, and is also a direction that urgently needs to be broken through in this field. Summary of the Invention

[0006] To address the balance between high efficiency, safety, and durability in existing antibacterial materials, this application aims to provide a manganese dioxide composite catalyst, its preparation method, and its application.

[0007] In a first aspect, this application provides a manganese dioxide composite catalyst comprising the following components: The basic MnO2 nanoparticles, the tannic acid surface modification layer coated on the surface of the basic MnO2 nanoparticles, and the functional components loaded through the tannic acid surface modification layer.

[0008] By employing the above technical solution, tannic acid reacts and oxidizes on the surface of MnO2 under alkaline conditions. Its catechol groups can partially reduce MnO2 and generate oxygen vacancies. Simultaneously, the quinone structure it forms binds with Mn ions and metal ions from the introduced functional components through coordination bonds, constructing a stable metal-polyphenol network. This network structure effectively prevents nanoparticle aggregation, exposes more active sites to improve catalytic efficiency, and serves as a molecular anchor to firmly lock in the functional components, achieving a fundamental shift from ion-dissolution sterilization to non-dissolution contact catalytic sterilization.

[0009] Optionally, the amount of tannic acid added is 50%-200% of the mass of the base MnO2 nanoparticles.

[0010] By adopting the above technical solution, the addition range can ensure that tannic acid fully covers the MnO2 surface and forms a complete modification layer, while avoiding excessive addition that would lead to a viscous reaction system or difficulties in subsequent processing.

[0011] Optionally, the amount of the functional component added is 0.1%-15% of the mass of the base MnO2 nanoparticles.

[0012] By adopting the above technical solution, the addition amount can control costs while ensuring antibacterial performance and avoiding the impact on the structural stability or dispersibility of the catalyst due to excessive introduction.

[0013] Optionally, the functional component is selected from at least one of alkali metal ions or transition metal ions.

[0014] Optionally, the alkali metal ion is selected from Na. + or K + One of the following; and / or, the transition metal ion is selected from Fe. 3 + Zn 2+ Cu 2+ At least one of them.

[0015] Optionally, the transition metal ion is Cu. 2+ With Zn 2+ The combination of Cu 2+ With Zn 2+ The molar ratio is 1:4.

[0016] By adopting the above technical solution, the Cu at this specific molar ratio 2+ With Zn 2+The combination can achieve a good balance between antibacterial spectrum, antibacterial efficiency and biocompatibility, resulting in synergistically enhanced antibacterial effects.

[0017] Optionally, the functional component includes boric acid.

[0018] Optionally, the amount of boric acid added is 0.1%-5% of the mass of the base MnO2 nanoparticles.

[0019] By adopting the above technical solution, the introduction of boric acid can further expand the antibacterial mechanism of the catalyst, enhance its ability to inhibit specific microorganisms, especially fungi, and within this addition range, it will not have an adverse effect on the overall structure and performance of the catalyst.

[0020] Optionally, the manganese dioxide catalyst is prepared by the following method: (1) Preparation of basic MnO2 nanoparticles; (2) The basic MnO2 nanoparticles are dispersed in water to form a suspension; (3) The tannic acid solution is mixed with the suspension and reacted under alkaline conditions to form the tannic acid surface modification layer on the surface of the basic MnO2 nanoparticles; wherein, in step (3), functional components may be introduced into the reaction system.

[0021] By adopting the above technical solution, surface modification and functional component loading can be achieved in the same reaction process, which is conducive to the formation of composite catalysts with uniform structure and strong bonding, and is suitable for large-scale preparation.

[0022] Secondly, this application provides an application of the manganese dioxide catalyst described in the first aspect above in the preparation of EVA composite foamed antibacterial insoles.

[0023] By adopting the above technical solution, the catalyst can be uniformly dispersed in polymer matrices such as EVA, maintaining structural stability during the foaming process, thereby endowing the final product with durable and efficient antibacterial properties.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. Constructing a metal-polyphenol network using tannic acid significantly enhances the catalytic activity of manganese dioxide and can synergistically enhance the catalytic activity of supported Cu. 2+ Zn 2+ Functional ions exhibit a high inhibition rate of nearly 99.9% against bacteria such as Staphylococcus aureus and Escherichia coli, as well as fungi such as Candida albicans. They have a broad antibacterial spectrum and are significantly more effective than unmodified MnO2 and some traditional silver-based antibacterial agents. 2. The functional components are firmly anchored within a stable coordination network. Under conditions such as simulated sweat immersion, Mn 2+ Cu 2+ Zn 2+ The concentration of metal ions leached is extremely low, achieving a non-leaching antibacterial mechanism, fundamentally avoiding the potential health and environmental risks caused by the release of heavy metal ions. 3. A robust metal-polyphenol coordination network ensures strong bonding between the catalyst's active center and the polymer matrix. After multiple simulated washes, the antibacterial performance retention rate remains above 97%, significantly better than traditional antibacterial materials that rely on ion dissolution and are prone to loss of active ingredients, thus meeting the requirements for functional durability during long-term use. 4. The preparation method of this catalyst is mild and highly controllable. By precisely controlling the types and proportions of the introduced functional components, its antibacterial spectrum and performance intensity can be specifically optimized. Benefiting from its good compatibility with common polymer substrates such as EVA and its easy processing characteristics, this catalyst has shown significant industrial application prospects in wearable products such as shoe insoles. Furthermore, this multifunctional catalytic material system can be further extended to multiple fields such as appliance surfaces, kitchenware coatings, building material additives, sanitary facilities, antibacterial packaging, air filtration, and water treatment media, providing a universal material solution for achieving broad, safe, and long-lasting antibacterial protection. Detailed Implementation

[0025] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Specific conditions not specified in the examples shall be carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0026] Potassium permanganate (CAS No. 7722-64-7), manganese sulfate (CAS No. 7785-87-7), concentrated sulfuric acid (CAS No. 7664-93-9), tannic acid (CAS No. 1401-55-4), ferric nitrate nonahydrate (CAS No. 7782-61-8), zinc chloride (CAS No. 7646-85-7), copper chloride (CAS No. 7447-39-4), and boric acid (CAS No. 10043-35-3) were all analytical grade reagents. Unless otherwise specified, all other substances were commercially available. Example 1

[0027] Solution preparation: Weigh 1.58 g of potassium permanganate and dissolve it in 40 mL of deionized water. Stir until completely dissolved to obtain solution A. Weigh 1.69 g of manganese sulfate, dissolve it in 40 mL of deionized water, and stir until completely dissolved to obtain solution B; Measure 2 mL of concentrated sulfuric acid and slowly add it dropwise to 200 mL of deionized water. Stir well to prepare a dilute sulfuric acid solution, which is used to adjust the pH of the reaction system.

[0028] Weigh 0.5 g of tannic acid and dissolve it in 50 mL of deionized water. Stir until completely dissolved to obtain an aqueous solution of tannic acid with a concentration of 10 mg / mL, which is solution C.

[0029] Preparation method: 1. Under stirring conditions, slowly add solution B to solution A. After the addition is complete, continue stirring for 30 minutes. Then, add the above dilute sulfuric acid solution dropwise until the pH of the reaction system is adjusted to between 2 and 3 to obtain a mixed solution. 2. Transfer the above mixture to a reaction vessel, heat it in an 85°C water bath with continuous stirring, and age it for 4-6 hours; 3. After the reaction is complete, the mixture is allowed to cool naturally to room temperature. The mixture is then filtered, centrifuged, and the resulting dark brown precipitate is collected. The precipitate is backwashed with deionized water until the pH of the washing solution is close to neutral. The washed solid is placed in a drying device and dried at 80°C for 12 h to obtain undoped MnO2 nanoparticles, which are the basic MnO2. 4. Weigh 0.5g of the above basic MnO2 nanoparticles, add 100 mL of deionized water, and ultrasonically disperse for 30 min to form a uniform suspension D; 5. Under continuous stirring, slowly add solution C to suspension D to mix evenly. Transfer the mixture to a reaction vessel and gently stir at 250 rpm under a 50°C water bath. At the 3rd hour of the reaction, weigh 0.06 g of NaOH, dissolve it in a small amount of water, and slowly add it dropwise to the reaction system. Continue to gently stir the reaction. The entire reaction should last for about 6 hours. 6. After the reaction was completed, the mixture was cooled to room temperature, and the solid product was collected by centrifugation. The obtained solid product was washed with deionized water 5 times, and then the washed solid product was placed in a vacuum drying oven and dried at 60°C for 12 h to obtain the composite catalyst modified with tannic acid surface. Example 2

[0030] The difference between this embodiment and Embodiment 1 is that the 0.06g NaOH in step 5 is replaced with 0.084g KOH. Example 3

[0031] The difference between this embodiment and Embodiment 1 is that 0.5g of tannic acid and 0.081g of ferric nitrate nonahydrate need to be added when preparing solution C. Example 4

[0032] The difference between this embodiment and Embodiment 1 is that 0.5g of tannic acid and 0.136g of zinc chloride need to be added when preparing solution C. Example 5

[0033] The difference between this embodiment and Embodiment 1 is that 0.5g of tannic acid and 0.034g of copper chloride need to be added when preparing solution C. Example 6

[0034] The difference between this embodiment and Embodiment 1 is that, in preparing solution C, 0.5g of tannic acid, 0.034g of copper chloride, and 0.0545g of zinc chloride need to be added. Example 7

[0035] The difference between this embodiment and Embodiment 1 is that, in preparing solution C, 0.5g of tannic acid, 0.034g of copper chloride, and 0.0136g of zinc chloride need to be added. Example 8

[0036] The difference between this embodiment and Embodiment 1 is that, in preparing solution C, 0.5g of tannic acid, 0.034g of copper chloride, and 0.136g of zinc chloride need to be added. Example 9

[0037] The difference between this embodiment and Embodiment 1 is that 0.5g of tannic acid and 0.031g of boric acid need to be added when preparing solution C. Comparative Example 1

[0038] The difference between this comparative example and Example 1 is that only basic MnO2 is used. Comparative Example 2

[0039] A silver-loaded zeolite-type inorganic antibacterial agent with a silver content of 2.0 wt% was used. Example 10 Preparation of composite antibacterial insoles

[0040] Ingredients: 100 parts EVA granules (supplied by Lotte, South Korea, VA content 19%), 18 parts catalysts prepared in each example and comparative example, AC foaming agent (purchased from Dongguan Weijie New Materials Co., Ltd., CAS No. 123-77-3), 1 part DCP crosslinking agent (supplied by Akzo, CAS No. 2212-81-9), 1 part zinc stearate (purchased from Dongguan Xingyuan Chemical Co., Ltd., CAS No. 557-05-1). Preparation method: All the above ingredients are mixed at 90°C until the components are evenly dispersed to obtain a compound, which is then processed into sheets. The obtained sheet-like compound was granulated, and the granules were left to mature at room temperature for 36 hours. Take an appropriate amount of matured granules and fill them into a pre-set insole mold. Perform molding and foaming. Set the process parameters to 170℃ and 12MPa. Hot press for 10 minutes, then quickly release the pressure to allow the material to foam and expand in the mold cavity. Finally, after cooling and shaping, open the mold and take out the foamed insole preform. The final EVA composite foamed insole is obtained by cutting and modifying the insole blank.

[0041] Performance testing Antibacterial performance test To verify the comprehensive performance of the composite catalyst prepared in this invention and its insole products, the following series of tests were conducted. The test samples were EVA composite foamed insoles prepared according to the method of Example 11, containing catalysts from each example and comparative example. All samples were cut to a standard size of 5 cm × 5 cm and irradiated with ultraviolet light for 30 minutes before use to remove potential surface contaminants.

[0042] According to the standard specifications, the blank control sample was made of pure EVA foam sheet, cut into a standard size of 5 cm × 5 cm, and was also irradiated with ultraviolet light for 30 minutes to remove potential contaminants on the surface.

[0043] Test method: Refer to the national standard GB / T 21510-2008 "Test Method for Antibacterial Properties of Nano-Inorganic Materials". Staphylococcus aureus (ATCC 6538, representing Gram-positive bacteria) and Escherichia coli (ATCC 25922, representing Gram-negative bacteria) were used as test bacteria, and Candida albicans (ATCC 10231) was used as test fungi.

[0044] Test procedure: Place the experimental group and blank control group samples into sterile Petri dishes, and take 0.2 mL of bacterial suspension (maintaining a concentration of 1×10⁻⁶). 5 A CFU / mL solution was evenly added to the sample surface, covered with a sterile film to ensure uniform contact between the bacterial solution and the sample, and the petri dish was then sealed. The bacterial test group was incubated at 37°C and 90% relative humidity for 18 hours; the fungal test group was incubated under the same conditions for 48 hours. After incubation, the sample was eluted in 20 mL of phosphate buffer by shaking. The eluent was then serially diluted and plated onto the appropriate agar plates for incubation and counting.

[0045] The formula for calculating the antibacterial rate is: Where R represents the inhibition rate (%), A represents the average number of recovered colonies (CFU / tablet) in the blank control sample, and B represents the average number of recovered colonies (CFU / tablet) in the test sample. Each test was performed in triplicate, and the average value was taken.

[0046] The results of the antibacterial performance test are shown in Table 1. Table 1

[0047] In all embodiments, modification with tannic acid was employed, resulting in excellent broad-spectrum antibacterial properties. The catechol groups in tannic acid can inhibit the growth of Mn on the surface of MnO2. 4+ Partially reduced to Mn 3+ Simultaneously, a large number of oxygen vacancies are created, significantly enhancing the redox potential and catalytic activity of the material. This enables it to more efficiently catalyze the generation of reactive oxygen species (ROS) from oxygen and water molecules in the environment, thus oxidizing and attacking microorganisms. The quinone structure formed after the oxidation of tannic acid, along with its phenolic hydroxyl groups, forms a metal-polyphenol coordination network with Mn ions, tightly coating the MnO2 surface. This network prevents the aggregation of MnO2 nanoparticles, increases the specific surface area, and its abundant polar functional groups can "adhere" to bacteria through strong hydrogen bonds and electrostatic forces, prolonging the action time and improving the bactericidal efficiency. The metal-polyphenol coordination network formed here acts as a carrier, loading various functional ions through coordination bonds to achieve functionalized doping.

[0048] In Example 1, a significant increase in bacterial and fungal inhibition rates was achieved solely through the modification of tannic acid. Subsequent examples were based on this method, demonstrating its universality and reliability. In Example 2, alkali metals were modified from Na... + Replace with K + This was used to verify that the tannic acid-polyphenol coordination network has a certain inclusiveness towards the types of alkali metal ions, whether Na... + Or K + All of these can be effectively integrated into the network and work synergistically with tannins to achieve highly efficient catalytic antibacterial function.

[0049] In Example 3, Fe was introduced. 3+ It can form Fenton-like catalytic centers with tannic acid. This type of catalyst can efficiently catalyze the generation of hydroxyl radicals under weakly acidic conditions, further accelerating the antibacterial kinetics. This catalytic synergistic effect surpasses the oxidation pathway that relies solely on MnO2.

[0050] In Examples 4-8, Zn was explored 2+ Cu 2+ The function of Zn and its combination in the whole system, as described in Example 4, is to introduce Zn. 2+ It is particularly effective in antifungal activity; Cu was introduced in Example 5. 2+ It showed good inhibition rates against all tested bacterial strains, and was also consistent with Cu. 2+This is related to the potent and broad-spectrum antibacterial properties. In Example 6, adjusting the Cu / Zn molar ratio to 1:4 resulted in a 99.9% inhibition rate against all tested strains, with Cu... 2+ It contributes a potent antifungal core, while Zn 2 + This approach supplements the broad-spectrum antibacterial properties while adjusting the biocompatibility of the material, avoiding the potential toxicity caused by high copper content. Determining the optimal molar ratio (1:4) is also one of the core points for achieving the superior performance of this solution. Data from Examples 7 and 8 further demonstrate the existence of the equilibrium point in Example 6 (molar ratio 1:4). While antifungal properties exist at a 1:1 ratio, the overall performance does not significantly surpass that of Example 6. Example 8 yields the same result, indicating that Example 6 can be considered the preferred solution.

[0051] In Example 9, boric acid was introduced. Although there was no significant improvement in antibacterial properties, it was still significantly better than the comparative example.

[0052] In Comparative Example 1, unmodified MnO2 showed an inhibition rate of approximately 75-78% against bacteria and only about 52% against fungi. This result confirms the limitations of unmodified MnO2 as an antibacterial material. Its limited activity depends on physical adsorption and weak surface oxidation, and the nanoparticles are prone to aggregation, resulting in a small effective contact area, thus failing to meet the requirements for efficient and reliable antibacterial action.

[0053] In Comparative Example 2, silver-loaded zeolite exhibited an extremely high inhibition rate against bacteria (99.9%), but its inhibition rate against fungi decreased to 85.4%. This also reflects two main characteristics of silver-based antibacterial agents: firstly, they rely on Ag. + It exhibits two main characteristics: firstly, it provides highly efficient and rapid sterilization upon dissolution; secondly, it has relatively low penetration efficiency through fungal cell walls, indicating a weakness in its antifungal spectrum. Meanwhile, Ag... + The continuous dissolution of the substance leads to an inherent contradiction between long-lasting efficacy and safety.

[0054] Security performance test The testing procedure is carried out in accordance with the ISO 3160-2 standard, as detailed below: Preparation of extract: Prepare artificial sweat solution with pH=5.5; Sample extraction: Accurately weigh 0.50 g of each sample powder, place it in a container, and add 25.0 mL of artificial sweat (solid-liquid ratio 1:50 w / v). After sealing, place it in a 37℃ constant temperature shaker and shake continuously at 60 rpm for 7 days; Separation and Detection: Immediately after extraction, the extract was filtered through a 0.22 μm filter membrane. The concentrations of four metal ions (Mn, Cu, Zn, and Ag) in the filtrate were directly determined using inductively coupled plasma mass spectrometry (ICP-MS). Parallel experiments: Three parallel experiments were set up for each sample, and the average value of the results was taken.

[0055] The test results are shown in Table 2. Table 2

[0056] Note: "<2" indicates that the value is below the instrument's limit of quantitation; "-" indicates that no addition was made or no detection is required.

[0057] The leaching data in Table 2 demonstrate the safety of the method. Comparative Example 1 shows significant manganese ion leaching, while Comparative Example 2 shows significant silver ion leaching, indicating that traditional materials relying on ion leaching for sterilization inherently carry safety and environmental risks. In contrast, the leaching concentrations of all target metals in Examples 1 and 6 were suppressed below the detection limit. This result fully confirms that the metal-polyphenol coordination network with a tannic acid framework can firmly anchor functional metal ions in the catalyst structure, achieving a fundamental shift from "leaching-type" to "non-leaching-type" contact catalytic sterilization. This avoids the potential harm to human health and the environment caused by heavy metal ions during long-term use and ensures the long-lasting effect of the antibacterial components, preventing rapid inactivation due to ion loss.

[0058] Durability test Durability testing was conducted in accordance with Appendix E of the standard QB / T2881-2013, Technical Conditions for Antimicrobial Performance of Footwear and Footwear Components. The test method is as follows: 1. The washing program should follow the procedures in GB / T8629-2001, with a washing time of 5 minutes; 2. In a washing machine, use 0.2% detergent (2 g / L) and tap water at a liquor ratio of 1:30 and a water temperature of (40±3)℃. Add the sample and wash for 5 minutes. Then rinse with clean water at room temperature. 3. After the first rinse, take out the test sample, dehydrate for 30 seconds, and then rinse a second time with clean water at room temperature; 4. After a second rinse of 2 minutes, remove the test sample and dehydrate for 30 seconds; 5. Steps 2, 3, and 4 above constitute one cycle, which is counted as one wash. Repeat these three steps until the predetermined number of washes (i.e., 10 times). To prevent residual detergent from interfering with the antibacterial test, ensure that the final wash uses plenty of clean water to thoroughly remove it. Then, dehydrate and dry the sample before using it for the antibacterial performance test, which is conducted using the same method as above. The durability test results are shown in Table 3.

[0059] Table 3

[0060]

[0061] The durability tests in Table 3 clearly demonstrate the long-term reliability of the solutions involved in the embodiments in actual use. Both Comparative Examples 1 and 2 showed a significant decrease in antibacterial performance after 10 washes, indicating that weak physical bonding easily leads to component loss, as well as the inherent defect of continuous dissolution and consumption of silver ions.

[0062] Examples 1 and 6 exhibited excellent durability, with antibacterial retention rates exceeding 97.5% and 99% respectively after washing, also thanks to the robust coordination network formed by tannic acid and metal ions. This network strongly anchors the catalytic active centers on the material surface and within the EVA matrix, effectively resisting physical friction and chemical detergent erosion during washing. It is particularly noteworthy that Example 6, containing Cu... 2+ Zn 2+ The fact that it can maintain a retention rate of nearly 99% even with two types of ions demonstrates the universality and robustness of its coordination network structure.

[0063] This invention achieves a synergistic balance of high-efficiency antibacterial activity, intrinsic safety, and long-lasting durability by constructing a key structure: a tannic acid-metal polyphenol coordination network. On one hand, this structure enhances enzyme catalytic activity through reduction and defect engineering, resulting in near 100% inhibition of bacteria and fungi, surpassing traditional silver-based antibacterial agents that rely on ion dissolution. On the other hand, this structure acts as a powerful molecular lock, firmly anchoring all functional ions, including manganese, copper, and zinc, reducing their dissolution concentration and eliminating the risk of heavy metal release, thus significantly improving safety. Simultaneously, this stable structure ensures the strong binding of the catalyst to the substrate, maintaining high antibacterial performance even after multiple washes, solving the performance degradation problem caused by silver ion loss in silver-based materials. Therefore, this invention successfully overcomes the inherent contradictions among high efficiency, safety, and durability in traditional antibacterial materials through the tannic acid-metal polyphenol coordination network, providing a novel solution with performance comprehensively surpassing existing technologies and significant market potential.

[0064] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application.

Claims

1. A manganese dioxide composite catalyst, characterized in that, Include: The basic MnO2 nanoparticles, the tannic acid surface modification layer coated on the surface of the basic MnO2 nanoparticles, and the functional components loaded through the tannic acid surface modification layer.

2. The manganese dioxide composite catalyst according to claim 1, characterized in that, The amount of tannic acid added is 50%-200% of the mass of the basic MnO2 nanoparticles.

3. The manganese dioxide composite catalyst according to claim 1, characterized in that, The amount of the functional component added is 0.1%-15% of the mass of the base MnO2 nanoparticles.

4. The manganese dioxide composite catalyst according to claim 1, characterized in that, The functional component is selected from at least one of alkali metal ions or transition metal ions.

5. The manganese dioxide composite catalyst according to claim 4, characterized in that, The alkali metal ions are selected from Na. + or K + One of the following; and / or, the transition metal ion is selected from Fe. 3+ Zn 2+ Cu 2+ At least one of them.

6. The manganese dioxide composite catalyst according to claim 5, characterized in that, The transition metal ion is Cu. 2+ With Zn 2+ The combination of Cu 2+ With Zn 2+ The molar ratio is 1:

4.

7. The manganese dioxide composite catalyst according to claim 4, characterized in that, The functional component includes boric acid.

8. The manganese dioxide composite catalyst according to claim 7, characterized in that, The amount of boric acid added is 0.1%-5% of the mass of the basic MnO2 nanoparticles.

9. The manganese dioxide composite catalyst according to claim 1, characterized in that, The manganese dioxide catalyst was prepared by the following method: (1) Preparation of basic MnO2 nanoparticles; (2) The basic MnO2 nanoparticles are dispersed in water to form a suspension; (3) The tannic acid solution is mixed with the suspension and reacted under alkaline conditions to form the tannic acid surface modification layer on the surface of the basic MnO2 nanoparticles; wherein, in step (3), the functional component may be introduced into the reaction system.

10. The application of the manganese dioxide composite catalyst as described in claims 1-9 in the preparation of EVA composite foamed antibacterial insoles.

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