An atomic transition metal modified nitrogen-carbon catalyst, a preparation method and application thereof
By preparing atomic-level transition metal-modified nitrogen-carbon catalysts with sharp-edged, wrinkled nanosheet structures, the problem of single-atom catalysts being unable to efficiently inactivate pathogenic microorganisms in existing technologies was solved. This achieved a synergistic effect of physicochemical processes, resulting in highly efficient photothermal catalytic inactivation of pathogenic microorganisms.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUN YAT SEN UNIV
- Filing Date
- 2023-07-17
- Publication Date
- 2026-07-10
AI Technical Summary
Existing single-atom catalysts cannot efficiently inactivate pathogenic microorganisms through photothermal catalysis, nor can they achieve synergistic effects of physicochemical processes.
An atomic-level transition metal-modified nitrogen-carbon catalyst was prepared. By forming a wrinkled nanosheet structure with sharp edges and combining it with metal active centers, a synergistic effect of physical and chemical processes was achieved, generating reactive oxygen species and rapidly and thoroughly inactivating pathogenic microorganisms.
It achieves highly efficient photothermal catalytic inactivation of pathogenic microorganisms, has broad-spectrum bactericidal ability, low cost, strong catalytic activity, and good stability.
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Figure CN117160503B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of environmental functional materials technology, and more specifically, to an atomic-level transition metal modified nitrogen-carbon catalyst, its preparation method, and its application. Background Technology
[0002] Microbial contamination poses a serious threat to the environment and human health, making its environmental risks extremely important. Related diseases such as diarrhea, cholera, and typhoid fever, transmitted by pathogenic microorganisms in water, directly or indirectly cause more than 2 million deaths annually. To ensure public health and water safety, further research is necessary to develop disinfection technologies and prevent pathogenic microorganism invasion. Common pathogenic microorganism contamination control technologies, such as chlorination, ozone, ultraviolet (UV) disinfection, and solar water disinfection, require continuous chemical additions or extra energy, which can easily lead to secondary pollution, limited disinfection range, high energy consumption, and high costs. Currently, chlorination, ozone, and UV disinfection technologies are widely used, but their broad-spectrum disinfection capabilities are unsatisfactory. Given the instability of sunlight, the high specific heat capacity of the environment, and low light absorption, the disinfection effect of solar disinfection technology is difficult to guarantee. However, solar disinfection technology is still considered an economical, ecological, and sustainable solution, favored for its low energy consumption, environmental friendliness, and wide applicability. However, these problems hinder the further development of traditional pathogenic microorganism contamination control technologies.
[0003] In recent years, advanced oxidation technologies have been widely applied in water disinfection. This technology not only possesses broad-spectrum bactericidal and disinfection capabilities but also produces no harmful byproducts during the disinfection process. Photothermal catalysis technology has significant advantages in this field: it utilizes solar energy as its energy source, avoiding the need for external oxidants. Compared to traditional photocatalysts—such as TiO2—photothermal catalytic materials can fully absorb light energy in the visible and near-infrared regions, utilizing solar energy more efficiently to generate more active species and heat to attack pathogenic microorganisms. Therefore, developing an economical and highly effective photothermal catalyst is crucial for achieving efficient inactivation of pathogenic microorganisms through photothermal catalysis technology.
[0004] The prior art discloses a single-atom catalyst, the preparation method of which includes the following steps: (1) mixing dicyandiamide, sodium chloride, a first transition metal salt and a solvent, freeze-drying to obtain a precursor, and then sintering it once under a protective atmosphere to obtain a graphite-phase carbon nitride-based support; (2) mixing the graphite-phase carbon nitride-based support obtained in step (1) with a second transition metal salt solution, allowing it to stand, and obtaining a precipitate; (3) sintering the precipitate obtained in step (2) a second time under a protective atmosphere to obtain the single-atom catalyst; wherein, the single atom is a transition metal single atom. The above material is a graphite-phase carbon nitride-based support loaded with transition metal single atoms, but it is only aimed at the removal of chemical pollutants and does not form a wrinkled nanosheet structure with sharp edges, so it cannot achieve physicochemical synergy and does not have the effect of rapid and thorough inactivation of pathogenic microorganisms. Summary of the Invention
[0005] The technical problem to be solved by this invention is to overcome the defects and shortcomings of existing single-atom catalysts that cannot achieve efficient photothermal catalytic inactivation of pathogenic microorganisms, and to provide an atomic-level transition metal modified nitrogen-carbon catalyst that achieves rapid and thorough inactivation of pathogenic microorganisms through the synergistic effect of physical and chemical processes.
[0006] Another objective of this invention is to provide a method for preparing an atomically modified nitrogen-carbon catalyst using transition metals.
[0007] Another objective of this invention is to provide an application of an atomically transition metal-modified nitrogen-carbon catalyst in photothermal catalytic water sterilization and disinfection.
[0008] The above-mentioned objective of this invention is achieved through the following technical solution:
[0009] An atomic-level transition metal-modified nitrogen-carbon catalyst, the catalyst being composed of wrinkled nanosheets with sharp edges, the wrinkled nanosheets comprising an N3C support and a transition metal uniformly distributed on the N3C support in the form of single atoms and atomic clusters.
[0010] It should be noted that:
[0011] The atomically modified nitrogen-carbon catalyst of this invention utilizes atomically modified transition metals to form active centers at metal sites, exhibiting highly efficient photothermal conversion and oxygen activation capabilities, and generating a large number of reactive oxygen species. 1 O2 and ·O 2- Meanwhile, the atomically modified nitrogen-carbon catalyst, composed of sharply edged wrinkled nanosheets, causes a certain degree of physical damage to bacteria, making it easier for reactive oxygen species to penetrate into the cell, producing a synergistic effect of physical and chemical processes, and achieving rapid and thorough inactivation of pathogenic microorganisms.
[0012] In specific embodiments, the transition metal elements of the present invention include one or more of Co, Fe, Mn, and Ni.
[0013] The aforementioned transition metal elements not only have good catalytic effects but are also inexpensive, readily available, and abundant in nature, making them easy to produce industrially.
[0014] The atomic-level transition metal modified nitrogen-carbon catalyst of the present invention can be CoN3C, FeN3C, MnN3C or NiN3C.
[0015] This invention also specifically protects a method for preparing an atomically transition metal-modified nitrogen-carbon catalyst, comprising the following steps:
[0016] S1. A precursor is obtained by ball milling a metal salt, trimesic acid, and dicyandiamide for 0.5–3 hours; S2. The obtained precursor is calcined at 700–900 °C in an inert gas atmosphere for 2–4 hours to obtain an atomically transition metal-modified nitrogen-carbon catalyst.
[0017] The ratio of metal salt, pyromellitic acid, and dicyandiamide is 0.03–0.08 mol: 0.5 g: 5 g.
[0018] It should be noted that:
[0019] In the preparation method of this invention, ball milling can thoroughly mix and disperse the metal salt and allow the precursor to form nanosheets with thin edges. Ball milling is the main reason for the formation of wrinkled nanosheets with sharp edges. Ball milling thins the material edges, retaining sharp edges after calcination. Uniform distribution is mainly achieved through ball milling, which has the effect of uniform mixing, resulting in a uniformly mixed precursor that can achieve uniform distribution of transition metals in the form of single atoms and atomic clusters, and uniform distribution after calcination.
[0020] The purpose of controlling the calcination temperature is to form a stable catalyst. Too low a temperature will prevent the formation of a stable structure, while too high a temperature will damage the material's structure (structural collapse). Similarly, controlling the calcination time is also for the purpose of forming a stable catalyst. Too short a calcination time will prevent the formation of a stable structure.
[0021] A better catalyst can be prepared by controlling the ratio of metal salt, trimesic acid, and dicyandiamide. When the proportion of metal salt is small, the synthesized material has fewer active sites. When the proportion of metal salt is large, it is easy to agglomerate during calcination, which is not conducive to the exposure of active sites and the catalytic activity of the material is not significantly improved. Controlling the ratio is to prepare a catalyst with better catalytic performance.
[0022] In the specific preparation method, the metal salt of the present invention can be a salt of the above-mentioned transition metals commonly used in the art, such as CoCl2, FeCl2, MnCl2 or NiCl2.
[0023] Preferably, the calcination temperature is 750–850°C. More preferably, the calcination temperature is 800°C.
[0024] Preferably, the ratio of the metal salt, trimesic acid and dicyandiamide is 0.04-0.06 mol: 0.5 g: 5 g.
[0025] More preferably, the ratio of the metal salt (CoCl2, FeCl2, MnCl2, NiCl2), trimesic acid, and dicyandiamide is 0.05 mol: 0.5 g: 5 g.
[0026] Preferably, the ball milling time in S1 is 1 to 3 hours.
[0027] Preferably, the calcination time in S2 is 3-4 hours, more preferably, the calcination time is 3 hours.
[0028] In a specific implementation, the inert gas can be an N2 atmosphere, and the flow rate of the calcined nitrogen is 40-80 ml / min.
[0029] This invention also specifically protects the application of an atomically transition metal-modified nitrogen-carbon catalyst in photothermal catalytic water sterilization and disinfection.
[0030] In specific applications, the preferred dosage of atomic-level transition metal-modified nitrogen-carbon catalysts is 0.5–2 mg / mL.
[0031] In specific applications, the photothermal catalysis light source for the atomic-level transition metal modified nitrogen-carbon catalyst of this invention is near-infrared light. Specifically, when the atomic-level transition metal modified nitrogen-carbon catalyst is used for photothermal sterilization, the near-infrared light is emitted by a xenon lamp with a 420nm filter and a power of 200W.
[0032] For specific application methods, please refer to the following:
[0033] The atomic-level transition metal modified nitrogen-carbon catalyst TM-N3C of this invention was added to the solution to be treated, stirred until homogeneous, and then irradiated with a xenon lamp to initiate the reaction. In the reaction system, the catalyst absorbs near-infrared light to generate a thermal effect, and the metal active centers of the catalyst can effectively activate oxygen to produce high concentrations of highly reactive active oxygen species (such as...). 1 O2 and ·O 2- It can effectively attack bacterial cells. In addition, the sharp surface of the TM-N3C catalyst causes physical damage to bacteria, which can effectively alleviate the oxidative load of reactive oxygen species during the disinfection process, promote the penetration of reactive oxygen species into cells, and thus lead to cell death.
[0034] The atomic-level transition metal modified nitrogen-carbon catalyst of the present invention can be applied to photothermal catalytic water sterilization and disinfection, especially for the sterilization and disinfection of Escherichia coli (E. coli K-12), Staphylococcus aureus (S. aureus), Salmonella (Salmonella), Enterococcus faecalis (E. faecalis), Aspergillus niger spores, and viruses (MS2).
[0035] The TM-N3C catalyst described in this invention exhibits high sterilization efficiency and broad-spectrum sterilization in wastewater treatment, particularly in high-efficiency photothermal sterilization processes, thereby improving effluent quality and meeting national wastewater discharge standards. Furthermore, the TM-N3C catalyst is simple to prepare, low in cost, and capable of efficiently generating ROS and achieving physical damage, while also possessing strong catalytic activity and good stability.
[0036] Compared with the prior art, the beneficial effects of the present invention are:
[0037] The atomic-level transition metal modified nitrogen-carbon catalyst of the present invention modifies transition metal atoms on the basis of nitrogen and carbon to construct metal active centers, thereby increasing the photothermal absorption capacity of the material without destroying the inherent morphology of the catalyst. It has a high efficiency of photothermal conversion, generates active oxygen species through molecular oxygen activation, and achieves physicochemical synergy by combining the sharp edges of the material, thus realizing efficient photothermal catalytic inactivation of pathogenic microorganisms.
[0038] The atomic-level transition metal modified nitrogen-carbon catalyst of this invention has high sterilization efficiency when applied to high-efficiency photothermal sterilization and disinfection wastewater treatment. It can achieve broad-spectrum sterilization, efficiently generate ROS and achieve physical damage, and has strong catalytic activity and good stable treatment properties. Attached Figure Description
[0039] Figure 1 and Figure 2 This is a scanning electron microscope (SEM) image of N3C.
[0040] Figure 3 SEM image of CoN3C
[0041] Figure 4 SEM image of FeN3C
[0042] Figure 5 SEM image of MnN3C
[0043] Figure 6 Scanning electron microscope (SEM) image of NiN3C
[0044] Figure 7 The X-ray diffraction (XRD) patterns of the TM-N3C catalysts prepared in Examples 1-4 are shown.
[0045] Figure 8 This is a spherical aberration electron microscope (HAADF-STEM) image of CoN3C.
[0046] Figure 9 This is a spherical aberration electron microscope (HAADF-STEM) image of FeN3.
[0047] Figure 10 This is a spherical aberration electron microscope (HAADF-STEM) image of MnN3C.
[0048] Figure 11 This is a spherical aberration electron microscope (HAADF-STEM) image of NiN3C.
[0049] Figure 12 The photothermal catalysis of the TM-N3C catalysts prepared in Examples 1-4 1 O2 and ·O 2- ESR diagram.
[0050] Figure 13 The image shows the UV-Vis-NIR absorption spectrum of the MnN3C catalyst prepared in Example 1.
[0051] Figure 14 The solution temperature diagram of the MnN3C catalyst prepared in Example 1 under simulated sunlight irradiation.
[0052] Figure 15 Infrared thermal imaging of the surface of the MnN3C catalyst prepared in Example 1 under simulated sunlight irradiation.
[0053] Figure 16 Density functional theory calculation models for the adsorption energy and bond length of O2 on the surface of the TM-N3C catalysts prepared in Examples 1-4. Detailed Implementation
[0054] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.
[0055] Example 1
[0056] An atomic-level transition metal modified nitrogen-carbon catalyst is disclosed. The catalyst consists of wrinkled nanosheets with sharp edges. The wrinkled nanosheets include an N3C support and a transition metal, Mn, uniformly distributed on the N3C support in the form of single atoms and atomic clusters.
[0057] The preparation method of the above-mentioned atomic-level transition metal modified nitrogen and carbon catalysts includes the following steps:
[0058] S1. 0.05 mol MnCl2, 500 mg of pyromellitic acid and 5.0 g of dicyandiamide were ball-milled for 2 h to obtain the precursor.
[0059] S2. Place the obtained precursor in a tube furnace, set the heating rate to 5℃ / min, and calcine to 800℃ for 3 hours. The entire calcination process is carried out under a nitrogen atmosphere with a nitrogen flow rate of 60 ml / min.
[0060] After calcination, the material was removed after cooling to room temperature to obtain the MnN3C catalyst.
[0061] The above-mentioned MnN3C catalyst was applied to photothermal sterilization, and the specific operation was as follows:
[0062] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10 A certain amount of MnN3C material (cfu / mL) was added and sampled at 5-minute intervals under 200W xenon lamp irradiation. The solution was diluted with sterile water at a dilution factor of 10,000, resulting in a concentration of 1 mg / mL of MnN3C material. The diluted suspension was evenly spread onto a solid culture medium and sterilized for 15 minutes. The medium was then incubated at 37°C under sterile conditions for 12 hours. The number of colonies on the medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0063] Example 2
[0064] An atomic-level transition metal modified nitrogen-carbon catalyst is disclosed. The catalyst consists of wrinkled nanosheets with sharp edges. The wrinkled nanosheets include an N3C support and a transition metal, Co, uniformly distributed on the N3C support in the form of single atoms and atomic clusters.
[0065] The preparation method of the above-mentioned atomic-level transition metal modified nitrogen and carbon catalysts includes the following steps:
[0066] S1. 0.05 mol CoCl2, 500 mg of trimesic acid and 5.0 g of dicyandiamide were ball-milled for 2 h to obtain the precursor.
[0067] S2. The obtained precursor was placed in a tube furnace, and the temperature was raised to 800℃ at a rate of 5℃ / min for calcination for 3 hours. The entire calcination process was carried out under a nitrogen atmosphere at a flow rate of 60 ml / min.
[0068] After calcination, the material was removed after cooling to room temperature to obtain the CoN3C catalyst.
[0069] The above-mentioned CoN3C catalyst was applied to photothermal sterilization, and the specific operation was as follows:
[0070] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10 A certain amount of CoN3C material (cfu / mL) was added and sampled at 5-minute intervals under 200W xenon lamp irradiation. The solution was diluted with sterile water at a dilution factor of 10,000, resulting in a CoN3C material concentration of 1 mg / mL. The diluted suspension was evenly spread onto a solid culture medium and sterilized for 15 minutes. The medium was then incubated at 37°C under sterile conditions for 12 hours. The colony count was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0071] Example 3
[0072] An atomic-level transition metal modified nitrogen-carbon catalyst is disclosed. The catalyst consists of wrinkled nanosheets with sharp edges. The wrinkled nanosheets include an N3C support and a transition metal, Fe, uniformly distributed on the N3C support in the form of single atoms and atomic clusters.
[0073] The preparation method of the above-mentioned atomic-level transition metal modified nitrogen and carbon catalysts includes the following steps:
[0074] S1. 0.05 mol FeCl2, 500 mg of pyromellitic acid and 5.0 g of dicyandiamide were ball-milled for 2 h to obtain the precursor.
[0075] S2. The obtained precursor was placed in a tube furnace, and the temperature was raised to 800℃ at a rate of 5℃ / min for calcination for 3 hours. The entire calcination process was carried out under a nitrogen atmosphere at a flow rate of 60 ml / min.
[0076] After calcination, the material was removed after cooling to room temperature to obtain the FeN3C catalyst.
[0077] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10 A certain amount of FeN3C material (cfu / mL) was added and sampled at 5-minute intervals under 200W xenon lamp irradiation. The solution was diluted with sterile water at a dilution factor of 10,000, resulting in a FeN3C material concentration of 1 mg / mL. The diluted suspension was evenly spread onto a solid culture medium and sterilized for 15 minutes. The medium was then incubated at 37°C under sterile conditions for 12 hours. The colony count was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0078] Example 4
[0079] An atomic-level transition metal modified nitrogen-carbon catalyst is disclosed. The catalyst consists of wrinkled nanosheets with sharp edges. The wrinkled nanosheets include an N3C support and a transition metal, Ni, uniformly distributed on the N3C support in the form of single atoms and atomic clusters.
[0080] The preparation method of the above-mentioned atomic-level transition metal modified nitrogen and carbon catalysts includes the following steps:
[0081] S1. 0.05 mol NiCl2, 500 mg pyromellitic acid and 5.0 g dicyandiamide were ball-milled for 2 h to obtain the precursor.
[0082] S2. The obtained precursor was placed in a tube furnace, and the temperature was raised to 800℃ at a rate of 5℃ / min for calcination for 3 hours. The entire calcination process was carried out under a nitrogen atmosphere at a flow rate of 60 ml / min.
[0083] After calcination, the material was removed after cooling to room temperature to obtain the NiN3C catalyst.
[0084] The above-mentioned NiN3C catalyst was applied to photothermal sterilization, and the specific operation was as follows:
[0085] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10 A certain amount of NiN3C material (cfu / mL) was added and sampled at 5-minute intervals under 200W xenon lamp irradiation. The solution was diluted with sterile water at a dilution factor of 10,000, with a NiN3C material concentration of 1 mg / mL. The diluted suspension was evenly spread onto a solid culture medium and sterilized for 15 minutes. The medium was then incubated at 37°C under sterile conditions for 12 hours. The colony count was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0086] Example 5
[0087] An atomic-level transition metal modified nitrogen-carbon catalyst is disclosed. The catalyst consists of wrinkled nanosheets with sharp edges. The wrinkled nanosheets include an N3C support and a transition metal, Mn, uniformly distributed on the N3C support in the form of single atoms and atomic clusters.
[0088] The preparation method of the above-mentioned atomic-level transition metal modified nitrogen and carbon catalysts includes the following steps:
[0089] S1. 0.03 mol MnCl2, 500 mg of pyromellitic acid and 5.0 g of dicyandiamide were ball-milled for 2 h to obtain the precursor.
[0090] S2. Place the obtained precursor in a tube furnace, set the heating rate to 5℃ / min, and calcine to 800℃ for 3 hours. The entire calcine process is carried out in a nitrogen atmosphere with a nitrogen flow rate of 60 ml / min.
[0091] After calcination, the material was removed after cooling to room temperature to obtain the MnN3C catalyst.
[0092] The above-mentioned MnN3C catalyst was applied to photothermal sterilization, and the specific operation was as follows:
[0093] A certain amount of MnN3C material was added to a magnetically stirred E. coli suspension of a certain volume. Under irradiation with a 200W xenon lamp, sampling was performed at 5-minute intervals. The suspension was diluted with sterile water at a dilution factor of 10,000, and the concentration of MnN3C material was 1 mg / mL. The diluted suspension was evenly spread onto a solid culture medium, and sterilization was performed for 15 minutes. The culture medium was then incubated at 37°C under sterile conditions for 12 hours. The number of colonies on the culture medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0094] Example 6
[0095] An atomic-level transition metal modified nitrogen-carbon catalyst is disclosed. The catalyst consists of wrinkled nanosheets with sharp edges. The wrinkled nanosheets include an N3C support and a transition metal, Mn, uniformly distributed on the N3C support in the form of single atoms and atomic clusters.
[0096] The preparation method of the above-mentioned atomic-level transition metal modified nitrogen and carbon catalysts includes the following steps:
[0097] S1. 0.08 mol MnCl2, 500 mg pyromellitic acid and 5.0 g dicyandiamide were ball-milled for 2 h to obtain the precursor.
[0098] S2. Place the obtained precursor in a tube furnace, set the heating rate to 5℃ / min, and calcine to 800℃ for 3 hours. The entire calcine process is carried out in a nitrogen atmosphere with a nitrogen flow rate of 60 ml / min.
[0099] After calcination, the material was removed after cooling to room temperature to obtain the MnN3C catalyst.
[0100] The above-mentioned MnN3C catalyst was applied to photothermal sterilization, and the specific operation was as follows:
[0101] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10A certain amount of MnN3C material (cfu / mL) was added and sampled at 5-minute intervals under 200W xenon lamp irradiation. The solution was diluted with sterile water at a dilution factor of 10,000, resulting in a concentration of 1 mg / mL of MnN3C material. The diluted suspension was evenly spread onto a solid culture medium and sterilized for 15 minutes. The medium was then incubated at 37°C under sterile conditions for 12 hours. The number of colonies on the medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0102] Example 7
[0103] The catalyst from Example 1 was applied to photothermal sterilization, and the specific operation was as follows:
[0104] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10 A certain amount of MnN3C material (cfu / mL) was added and sampled at 5-minute intervals under 200W xenon lamp irradiation. The solution was diluted with sterile water at a dilution factor of 10,000, resulting in a concentration of 0.5 mg / mL of MnN3C material. The diluted suspension was evenly spread onto a solid culture medium and sterilized for 15 minutes. The medium was then incubated at 37°C under sterile conditions for 12 hours. The number of colonies on the medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0105] Example 8
[0106] The catalyst from Example 1 was applied to photothermal sterilization, and the specific operation was as follows:
[0107] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10 A certain amount of MnN3C material (cfu / mL) was added and sampled at 5-minute intervals under 200W xenon lamp irradiation. The solution was diluted with sterile water at a dilution factor of 10,000, resulting in a concentration of 2 mg / mL of MnN3C material. The diluted suspension was evenly spread onto a solid culture medium and sterilized for 15 minutes. The medium was then incubated at 37°C under sterile conditions for 12 hours. The number of colonies on the medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0108] Example 9
[0109] The catalyst from Example 1 was applied to photothermal sterilization, and the specific operation was as follows:
[0110] A certain amount of MnN3C material was added to a volume of Staphylococcus aureus suspension (initial concentration 6.50 log10 cfu / mL) under continuous magnetic stirring. Sampling was performed at 5-minute intervals under 200W xenon lamp irradiation. The suspension was diluted with sterile water at a dilution factor of 10,000, and the concentration of MnN3C material used was 1 mg / mL. The diluted suspension was evenly spread onto a solid culture medium, and sterilization was performed for 15 minutes. The medium was then incubated at 37℃ under sterile conditions for 12 hours. The number of colonies on the medium was recorded, and the concentration of inactivated Staphylococcus aureus was calculated. The results are shown in Table 1.
[0111] Example 10
[0112] The catalyst from Example 1 was applied to photothermal sterilization, and the specific operation was as follows:
[0113] A certain amount of MnN3C material was added to a certain volume of MS2 virus suspension (initial concentration 3.10 log10 cfu / mL) under continuous magnetic stirring. Sampling was performed at 5-minute intervals under 200W xenon lamp irradiation. The solution was diluted with sterile water at a dilution factor of 10,000. The concentration of MnN3C material used was 1 mg / mL. The inactivated MS virus concentration was determined using the double-layer agar plate method after sampling, with a sterilization time of 15 minutes. The results are shown in Table 1.
[0114] Example 11
[0115] The catalyst from Example 1 was applied to heat sterilization, and the specific operation was as follows:
[0116] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10 A certain amount of MnN3C material (cfu / mL) was added, and the reactor was placed in the dark for reaction. Sampling was performed at 5-minute intervals. The solution was diluted with sterile water at a dilution factor of 10,000. The concentration of MnN3C material used was 1 mg / mL. The diluted suspension was evenly spread on a solid culture medium, and sterilization was performed at 15 minutes. The culture medium was then incubated at a constant temperature of 37°C for 12 hours. The number of colonies on the culture medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0117] Example 12
[0118] The catalyst from Example 2 was applied to heat sterilization, and the specific operation was as follows:
[0119] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10A certain amount of CoN3C material (cfu / mL) was added, and the reactor was placed in the dark for reaction. Sampling was performed at 5-minute intervals. The solution was diluted with sterile water at a dilution factor of 10,000. The concentration of CoN3C material used was 1 mg / mL. The diluted suspension was evenly spread on a solid culture medium, and sterilization was performed at 15 minutes. The culture medium was then incubated at 37°C under sterile conditions for 12 hours. The number of colonies on the culture medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0120] Example 13
[0121] The catalyst from Example 3 was applied to heat sterilization, and the specific operation was as follows:
[0122] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10 A certain amount of FeN3C material (cfu / mL) was added, and the reactor was placed in the dark for reaction. Sampling was performed at 5-minute intervals. The solution was diluted with sterile water at a dilution factor of 10,000. The concentration of FeN3C material used was 1 mg / mL. The diluted suspension was evenly spread on a solid culture medium, and sterilization was performed at 15 minutes. The culture medium was then incubated at 37°C under sterile conditions for 12 hours. The number of colonies on the culture medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0123] Example 14
[0124] The catalyst from Example 4 was applied to heat sterilization, and the specific operation was as follows:
[0125] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10 A certain amount of NiN3C material (cfu / mL) was added, and the reactor was placed in the dark for reaction. Sampling was performed at 5-minute intervals. The solution was diluted with sterile water at a dilution factor of 10,000. The concentration of NiN3C material used was 1 mg / mL. The diluted suspension was evenly spread on a solid culture medium, and sterilization was performed at 15 minutes. The culture medium was then incubated at 37°C under sterile conditions for 12 hours. The number of colonies on the culture medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0126] Example 15
[0127] The catalyst from Example 1 was applied to photo-sterilization, and the specific operation was as follows:
[0128] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10A certain amount of MnN3C material (cfu / mL) was added. Under irradiation with a 200W xenon lamp, the reactor was placed in a petri dish containing an appropriate amount of ice. The reaction system temperature was maintained at 25℃, and sampling was performed at 5-minute intervals. The solution was diluted with sterile water at a dilution factor of 10,000. The concentration of MnN3C material used was 1 mg / mL. The diluted suspension was evenly spread on a solid culture medium, and sterilization was performed for 15 minutes. The culture medium was then incubated at a constant temperature of 37℃ for 12 hours. The number of colonies on the culture medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0129] Example 16
[0130] The catalyst from Example 1 was applied to heat sterilization, and the specific operation was as follows:
[0131] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10 A certain amount of MnN3C material (cfu / mL) was added, and the reactor was heated in a water bath at 60℃ in the dark. Sampling was performed at 5-minute intervals. The solution was diluted with sterile water at a dilution factor of 10,000. The concentration of MnN3C material used was 1 mg / mL. The diluted suspension was evenly spread onto a solid culture medium, and sterilization was performed for 15 minutes. The medium was then incubated at 37℃ under sterile conditions for 12 hours. The number of colonies on the medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0132] Comparative Example 1
[0133] A nitrogen-carbon catalyst, the preparation method of which includes the following steps:
[0134] S1. 500 mg of pyromellitic acid and 5.0 g of dicyandiamide were ball-milled for 2 hours to obtain the precursor.
[0135] S2. The obtained precursor was placed in a tube furnace, and the heating rate was set to 5℃ / min, and the temperature was raised to 800℃ for calcination for 3 hours. The entire calcination process was carried out in a nitrogen atmosphere with a nitrogen flow rate of 60 ml / min.
[0136] S3. After calcination, the material is removed after cooling to room temperature to obtain the N3C catalyst.
[0137] The above-mentioned N3C catalyst was applied to photothermal sterilization, and the specific operation was as follows:
[0138] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10A certain amount of N3C material (cfu / mL) was added, and samples were taken at 5-minute intervals under irradiation with a 200W xenon lamp. The solution was diluted with sterile water at a dilution factor of 10,000, and the concentration of N3C material was 1 mg / mL. The diluted suspension was evenly spread onto a solid culture medium, and sterilization was performed for 15 minutes. The medium was then incubated at 37°C under sterile conditions for 12 hours. The number of colonies on the medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0139] Comparative Example 2
[0140] The catalyst from Comparative Example 1 was applied to thermal sterilization, and the specific operation was as follows:
[0141] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10 A certain amount of N3C material (cfu / mL) was added, and the reactor was placed in the dark for reaction. Sampling was performed at 5-minute intervals. The solution was diluted with sterile water at a dilution factor of 10,000. The concentration of N3C material used was 1 mg / mL. The diluted suspension was evenly spread on a solid culture medium, and sterilization was performed at 15 minutes. The culture medium was then incubated at a constant temperature of 37°C for 12 hours. The number of colonies on the culture medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0142] Comparative Example 3
[0143] A nitrogen-carbon catalyst, the preparation method of which includes the following steps:
[0144] S1. A precursor was obtained by mixing 0.05 mol MnCl2, 500 mg of pyromellitic acid, and 5.0 g of dicyandiamide.
[0145] S2. Place the obtained precursor in a tube furnace, set the heating rate to 5℃ / min, and calcine to 800℃ for 3 hours. The entire calcination process is carried out under a nitrogen atmosphere with a nitrogen flow rate of 60 ml / min.
[0146] After calcination, the material was removed after cooling to room temperature to obtain the MnN3C catalyst.
[0147] The above-mentioned MnN3C catalyst was applied to photothermal sterilization, and the specific operation was as follows:
[0148] A suspension of *E. coli* (initial concentration 7.10 log) was continuously stirred with magnetic force to a certain volume. 10A certain amount of MnN3C material (cfu / mL) was added and sampled at 5-minute intervals under 200W xenon lamp irradiation. The solution was diluted with sterile water at a dilution factor of 10,000, resulting in a concentration of 1 mg / mL of MnN3C material. The diluted suspension was evenly spread onto a solid culture medium and sterilized for 15 minutes. The medium was then incubated at 37°C under sterile conditions for 12 hours. The number of colonies on the medium was recorded, and the concentration of inactivated E. coli was calculated. The results are shown in Table 1.
[0149] Result detection
[0150] 1. Scanning electron microscopy (SEM) detection
[0151] The Mn-N3C prepared in Example 1, the Co-N3C prepared in Example 2, the Fe-N3C prepared in Example 3, the Ni-N3C prepared in Example 4, and the N3C prepared in Comparative Example 1 were examined by scanning electron microscopy (SEM). The results are as follows: Figures 1-6 As shown.
[0152] As can be seen from the figure, CoN3C, FeN3C, MnN3C, NiN3C and N3C are all composed of wrinkled nanosheets with sharp edges. That is, the doping of metals does not cause significant changes in the microstructure of nitrogen-carbon materials, and the materials have sharp edges.
[0153] 2. X-ray diffraction (XRD) test
[0154] X-ray diffraction analysis was performed on the Mn-N3C prepared in Example 1, the Co-N3C prepared in Example 2, the Fe-N3C prepared in Example 3, the Ni-N3C prepared in Example 4, and the N3C prepared in Comparative Example 1. The obtained XRD patterns are shown below. Figure 7 As shown, CoN3C, FeN3C, MnN3C, NiN3C and N3C all exhibit broad and weak diffraction peaks around 26°, which can be attributed to the (002) plane of graphite carbon. At the same time, no peaks belonging to the relevant metals or metal oxides were detected, indicating that the metals in the examples are doped onto the nitrogen-carbon material with a small particle size.
[0155] 3. Aberration-Altered Electron Microscopy (HAADF-STEM) Testing
[0156] The distribution of relevant metals on CoN3C, FeN3C, MnN3C, and NiN3C prepared in Examples 1-4 was observed using spherical aberration electron microscopy (HAADF-STEM). The results are as follows: Figures 8-11As shown in the figure, no particle aggregation was observed on the TM-N3C support. Based on the bright spots at atomic size, HAADF-STEM images confirmed that Co, Fe, Mn, and Ni species are mainly distributed uniformly on the N3C support in the form of single atoms and atomic clusters, rather than nanoparticles.
[0157] 4. ESR test
[0158] The bioactive species generated by the TM-N3C photothermal sterilization system were analyzed using ESR testing. DMPO was used as a trapping agent to detect the ·O2 content in different systems. - And ·OH, using TEMP as a trap to detect singlet oxygen in different systems ( 1 O2), the ESR of the TM-N3C materials prepared in Examples 1-4 was measured. The results are as follows. Figure 12 As shown.
[0159] like Figure 12 As shown in (a), TEMP- can be captured in the photothermal systems of CoN3C, FeN3C, MnN3C, and NiN3C. 1 The O2 signal, with a characteristic peak of 1:1:1, indicates that the photothermal systems of CoN3C, FeN3C, MnN3C, and NiN3C all produced O2. 1 O2, the signal strength difference is not significant. For example... Figure 12 As shown in (b), DMPO-·O2 can be captured in the photothermal systems of CoN3C, FeN3C, MnN3C, and NiN3C. - The six-peak signal indicates that the photothermal systems of CoN3C, FeN3C, MnN3C, and NiN3C all generated ·O2. - The O2 generated by the MnN3C photothermal system - This is several times higher than other systems. Furthermore, no signal with a characteristic peak of 1:2:2:1 DMPO-·OH was detected in the CoN3C, FeN3C, MnN3C, and NiN3C photothermal systems, indicating that ·OH was not generated in these systems. Figure 12 (cd) indicates that as the reaction time progresses, the TM-N3C photothermal system produces... 1 The O2 concentration first increased and then decreased because of the production 1 O2 underwent quenching, while its production of O2... - The continuously increasing concentration indicates that the main free radicals produced by the photothermal system are ·O2. - .
[0160] 5. Photothermal sterilization performance test
[0161] The results of the above bactericidal effect test are shown in Table 1.
[0162] Table 1. Results of sterilization performance testing of atomic-level metal nitrogen-carbon catalysts (sterilization time 15 min)
[0163]
[0164]
[0165] As shown in Table 1, the bactericidal performance of atomically transition metal-modified nitrogen-carbon materials (Examples 1-4) is significantly better than that of nitrogen-carbon materials (Comparative Example 5). Among them, Mn-N3C has the best bactericidal performance. The photothermal bactericidal performance of the TM-N3C system is ranked as follows: MnN3C>FeN3C>CoN3C>NiN3C>N3C.
[0166] Examples 1, 5, and 6 changed the Mn loading by altering the proportion of MnCl2 in the precursor. The results showed that the bactericidal performance was poor when the proportion of MnCl2 was low, indicating insufficient active sites. When the Mn loading was high, the bactericidal performance was improved, and 7.10 log10 cfu / mL of Escherichia coli could be completely killed within 15 min.
[0167] Examples 1, 7, and 8 show that by changing the dosage of catalyst MnN3C, increasing the dosage of MnN3C can enhance the bactericidal effect. A catalyst dosage of 1 mg / mL can completely kill 7.10 log10 cfu / mL of Escherichia coli within 15 min.
[0168] Examples 9 and 10 show that Staphylococcus aureus and MS2 virus were killed respectively, and the photothermal system based on MnN3C catalyst can completely kill 6.50 log [virus name missing] within 15 min. 10 CFU / mL Staphylococcus aureus and 3.10 log 10 MS2 virus at cfu / mL.
[0169] As can be seen from the above embodiments, the TM-N3C material of the present invention has a physical bactericidal effect under dark and room temperature conditions (Examples 11-14), and can inactivate 0.15-0.22 log 10 As can be seen from the comparison of Comparative Example 2, the physical bactericidal effects of N3C and TM-N3C are not significantly different. Excluding the toxic effects of metal ion leaching on bacterial cells, the damage to bacteria is mainly caused by the sharp edges of the materials themselves. The Mn-N3C material of this invention does not achieve good bactericidal effects under either light irradiation (Example 15) or heat sterilization (Example 16), and its bactericidal effect is lower than that of the photothermal system (Example 1), indicating that the catalyst has a photothermal synergistic effect.
[0170] Among them, the MnN3C catalyst in Comparative Example 3 could not form sharp-edged wrinkled nanosheets because it was not ball-milled, and therefore could not form a synergistic effect of physicochemical sterilization, resulting in a significantly lower sterilization count than in Example 1.
[0171] In summary, the TM-N3C described in this invention can achieve photothermal catalytic inactivation of pathogenic microorganisms, realize synergistic physical and chemical sterilization and disinfection, and has a spectral sterilization effect.
[0172] 6. Photothermal conversion capability test
[0173] Depend on Figure 13 It can be seen that the light absorption capacity of MnN3C photothermal material has expanded to the full spectrum, with the absorption edge located at 905 nm, belonging to the near-infrared region, and its energy band gap is 1.37 eV, indicating that the MnN3C catalyst has excellent light absorption capacity. Figure 14 It can be seen that under simulated sunlight irradiation, the water temperature of the MnN3C photothermal system rapidly rose to the equilibrium temperature of 56.3℃ within 15 minutes, while the blank control group only reached 38.4℃. Figure 15 As shown, the surface photothermal conversion of MnN3C was directly monitored. After 10 minutes of simulated sunlight irradiation, the surface temperature of MnN3C powder increased from 26.3℃ to 96.2℃, indicating that MnN3C has excellent photothermal conversion capabilities.
[0174] 7. Density functional theory calculations
[0175] Depend on Figure 16 It can be seen that the O2 bond length of the O2 molecule before adsorption is The O2 bond lengths on the surfaces of CoN3C, FeN3C, MnN3C, and NiN3C are... The O and O bond lengths increased compared to when they were not adsorbed, and longer bonds are more easily deformed and activated. That is, the order of molecular oxygen adsorption and activation ability of the catalyst TM-N3C is MnN3C > FeN3C > CoN3C > NiN3C. This indicates that the excellent bactericidal performance of the MnN3C photothermal system of this invention comes from the adsorption and activation of molecular oxygen by MnN3C.
[0176] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. The application of an atomically transition metal-modified nitrogen-carbon catalyst in photothermal catalytic water sterilization and disinfection, characterized in that, The atomic-level transition metal modified nitrogen-carbon catalyst is composed of wrinkled nanosheets with sharp edges. The wrinkled nanosheets include an N3C support and a transition metal uniformly distributed on the N3C support in the form of single atoms and atomic clusters. The preparation method of the atomic-level transition metal modified nitrogen-carbon catalyst includes the following steps: S1. Ball milling metal salt, trimesic acid and dicyandiamide for 0.5-3 h to obtain a precursor; S2. Calcining the obtained precursor at 700-900℃ in an inert gas atmosphere for 2-4 h to obtain the atomic-level transition metal modified nitrogen-carbon catalyst; wherein the transition metal is Mn; The ratio of metal salt, trimesic acid, and dicyandiamide is 0.03~0.08 mol : 0.5 g : 5 g.
2. The application as described in claim 1, characterized in that, The metal salt is MnCl2.
3. The application as described in claim 1, characterized in that, The calcination temperature is 750~850℃.
4. The application as described in claim 1, characterized in that, The ratio of the metal salt, trimesic acid, and dicyandiamide is 0.04~0.06 mol: 0.5 g: 5 g.
5. The application as described in claim 1, characterized in that, The amount of the atomic-level transition metal modified nitrogen-carbon catalyst used is 0.5–2 mg / mL.
6. The application as described in claim 1, characterized in that, The light source for the photothermal catalysis is near-infrared light.
7. The application as described in claim 1, characterized in that, The sterilizing and disinfecting microorganisms include one or more of Escherichia coli, Staphylococcus aureus, Salmonella, Enterococcus faecalis, and Aspergillus niger spores.