Biomass-based carbon-loaded transition metal monatomic catalyst as well as preparation method and application thereof

Abstract

The invention provides a biomass-based carbon-loaded transition metal monatomic catalyst as well as a preparation method and application thereof. The preparation method of the catalyst comprises the following steps: fully dispersing biomass and transition metal salt in deionized water, aging, centrifuging and drying to obtain a biomass-transition metal precursor; and grinding and uniformly mixing the biomass-transition metal precursor and a nitrogen source, and calcining to obtain the catalyst. The preparation process is simple, low in cost, green and sustainable; in the obtained catalyst, the transition metal is uniformly loaded on the biomass-based carbon in a monatomic site form; the obtained biomass-based carbon-loaded transition metal monatomic catalyst has good biocompatibility, and has great application extendable potential in the aspects of biological sterilization and wound inflammation diminishing.

Description

Technical Field

[0001] This invention relates to a biomass-based carbon-supported transition metal single-atom catalyst, its preparation method, and its application, belonging to the field of catalyst material design and preparation. Background Technology

[0002] Single-atom catalysts possess highly evolved active centers M-Nx (M representing a transition metal) similar to those of natural metalloenzymes, and exhibit advantages such as high activity, high stability, recyclability, and ease of preparation and storage, making them an ideal alternative to natural metalloenzymes.

[0003] Currently, the typical synthesis strategy for carbon-based supported transition metal single-atom catalysts usually employs soluble metal salts or metal complexes as metal source precursors, while using nitrogen / carbon-containing organic compounds as precursors for the nitrogen-doped carbon matrix. Both are homogeneously dissolved and mixed in an aqueous or organic solvent system to ensure high dispersion of metal ions in the reaction system. Subsequent heat treatment steps, such as drying and high-temperature calcination, yield the single-atom catalyst. However, under high-temperature synthesis conditions, especially when the metal loading reaches a certain threshold, metal atoms are prone to irreversible aggregation, forming metal clusters or nanoparticles. To obtain highly dispersed single-atom catalysts, subsequent acid washing is often required to remove agglomerates. However, this process involves complex procedures, prolonging the overall production cycle, and requires stringent process conditions, while also generating a large amount of waste liquid, severely restricting the practical application of this synthesis method in the large-scale production of single-atom catalysts.

[0004] Compared to petroleum resources, which are currently commonly used to produce carbon carriers, biomass is abundant in nature, has good environmental compatibility, usually has a relatively stable three-dimensional skeleton structure, and most of it is very low in cost.

[0005] Therefore, by using waste biomass as a precursor, we can develop a method for preparing carbon-supported transition metal single-atom catalysts that features simplified process flow and economical preparation costs. This method can not only achieve efficient loading of single-atom sites, but also provide a new way for the high-value utilization of waste biomass. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a biomass-based carbon-supported transition metal single-atom catalyst, its preparation method, and its applications. The preparation process of this invention is simple, low-cost, and environmentally sustainable. In the obtained catalyst, the transition metal is uniformly supported on the biomass-based carbon in the form of single-atom sites. The resulting biomass-based carbon-supported transition metal single-atom catalyst exhibits good biocompatibility and has significant potential for expansion in applications such as bio-sterilization and wound anti-inflammatory treatment.

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

[0008] The first objective of this invention is to provide a transition metal single-atom catalyst supported on biomass-based carbon, wherein the catalyst is a transition metal uniformly supported on biomass-based carbon in the form of single-atom sites.

[0009] According to a preferred embodiment of the present invention, the microstructure of the biomass-based carbon-supported transition metal single-atom catalyst is: a pleated nanosheet with a porous structure.

[0010] According to a preferred embodiment of the present invention, the specific surface area of ​​the biomass-based carbon-supported transition metal single-atom catalyst is 400-500 m². 2 / g.

[0011] According to a preferred embodiment of the present invention, the loading amount of transition metal single atoms in the biomass-based carbon-supported transition metal single-atom catalyst is 0.20 wt% to 4.90 wt%. The loading amount refers to the percentage of the mass of the transition metal single atom relative to the mass of the biomass-based carbon.

[0012] A second objective of this invention is to provide a method for preparing the above-mentioned biomass-based carbon-supported transition metal single-atom catalyst, comprising the following steps:

[0013] (1) Biomass and transition metal salts are fully dispersed in deionized water, aged, centrifuged and dried to obtain biomass-transition metal precursor;

[0014] (2) The biomass-transition metal precursor and nitrogen source are ground and mixed evenly, and then calcined to obtain a biomass-based carbon-supported transition metal single-atom catalyst.

[0015] According to a preferred embodiment of the present invention, in step (1), the biomass is selected from carbon-containing biomass in nature; preferably, the biomass is selected from one or more combinations of lignin, cellulose or hemicellulose extracted from rice husks, bamboo leaves, straw, leaves or wood.

[0016] According to a preferred embodiment of the present invention, in step (1), the transition metal salt is at least one of a soluble iron salt, a soluble cobalt salt, a soluble nickel salt, a soluble copper salt, a soluble manganese salt, or a soluble zinc salt.

[0017] Preferably, the transition metal salt is at least one of ferrous chloride, ferric nitrate, ferric chloride, cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, nickel chloride, nickel nitrate, nickel acetate, copper acetate, copper chloride, copper nitrate, manganese acetate, manganese chloride, manganese nitrate, zinc chloride, zinc acetate, or zinc nitrate.

[0018] According to a preferred embodiment of the present invention, in step (1), the mass ratio of biomass to transition metal salt is 0.2-10:1.

[0019] According to a preferred embodiment of the present invention, in step (1), the mass ratio of biomass to deionized water is 0.1-10:250.

[0020] According to a preferred embodiment of the present invention, in step (1), the mixture is stirred at room temperature for 0.5 to 3 hours to fully disperse the mixture; the aging time is 6 to 24 hours, and the aging is carried out under static conditions at room temperature; the centrifugation speed is 3000 to 5000 r / min, and the centrifugation time is 1 to 5 minutes; the drying temperature is 50 to 80°C, and the drying time is 10 to 24 hours.

[0021] According to a preferred embodiment of the present invention, in step (2), the nitrogen source is at least one selected from 1,2,4,5-tetraaminobenzene, urea, ammonium nitrate, p-phenylenediamine, 4,4'-bipyridine, cyanamide, ethylenediamine, polyethyleneimine, dicyandiamide, or melamine. Preferably, the nitrogen source is at least one selected from urea, cyanamide, ethylenediamine, polyethyleneimine, dicyandiamide, or melamine.

[0022] According to a preferred embodiment of the present invention, in step (2), the mass ratio of biomass-transition metal precursor to nitrogen source is 1:1-30.

[0023] According to a preferred embodiment of the present invention, in step (2), the grinding and mixing time is 10-30 min.

[0024] According to a preferred embodiment of the present invention, in step (2), the calcination is carried out in a protective gas, which is one of nitrogen, argon or a nitrogen-argon mixture, the flow rate of the protective gas is 30-80 mL / min, the calcination temperature is 700-800℃, and the calcination time is 1-4 h.

[0025] Another object of the present invention is to provide the application of the above-mentioned biomass-based carbon-supported transition metal single-atom catalyst in antibacterial or preparation of antibacterial drugs or dressings.

[0026] According to a preferred embodiment of the present invention, the biomass-based carbon-supported transition metal single-atom catalyst is used for bactericidal or bacteriostatic effects on Escherichia coli and / or Staphylococcus aureus.

[0027] The technical features and beneficial effects of this invention are as follows:

[0028] (1) This invention employs a mixed coordination of waste biomass and transition metal salts to form a transition metal precursor. The transition metal ions form stable coordination bonds with the phenolic hydroxyl groups of the biomass, confining it within the three-dimensional network structure of the biomass. Then, through in-situ anion exchange during nitrogen-assisted pyrolysis, the formation of the precursor and the anchoring of the metal are simultaneously achieved, resulting in a simple preparation process. This invention uses inexpensive waste biomass as a carbon source, transforming it into a valuable resource and reducing costs. The method of this invention can prepare various biomass-based carbon-supported transition metal single-atom catalysts and can perform high-value treatment of waste biomass. The preparation process is simple, low-cost, green, sustainable, and biocompatible, with broad practical application prospects.

[0029] (2) The nitrogen content of the catalyst obtained by the present invention can reach 10wt%, which is beneficial to the anchoring of transition metal single atoms. Moreover, the catalyst prepared does not require acid washing process, avoiding problems such as waste acid treatment and equipment wear and tear, reducing production costs, and being green and environmentally friendly.

[0030] (3) The biomass-based carbon-supported transition metal single-atom catalyst prepared by the present invention has a high specific surface area and metal loading, and good biocompatibility. The biomass-based carbon-supported transition metal single-atom catalyst can achieve a sterilization rate of over 99.9% when used for antibacterial purposes. Attached Figure Description

[0031] Figure 1 This is a scanning electron microscope (SEM) image of the biomass-based carbon-supported transition metal single-atom catalyst in Example 1.

[0032] Figure 2 This is a transmission electron microscope (TEM) image of the biomass-based carbon-supported transition metal single-atom catalyst in Example 1.

[0033] Figure 3 This is the elemental distribution diagram of the biomass-based carbon-supported transition metal single-atom catalyst in Example 1.

[0034] Figure 4 The X-ray diffraction (XRD) pattern is that of the biomass-based carbon-supported transition metal single-atom catalyst in Example 1.

[0035] Figure 5 This is a high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) image of the biomass-based carbon-supported transition metal single-atom catalyst in Example 1.

[0036] Figure 6 The images show the N2 adsorption-desorption isotherms and pore size distribution of the biomass-based carbon-supported transition metal single-atom catalyst prepared in Example 1.

[0037] Figure 7 The image shows a HAADF-STEM image of the biomass-based carbon-supported transition metal single-atom catalyst in Example 4.

[0038] Figure 8 HAADF-STEM image of the biomass-based carbon-supported transition metal single-atom catalyst in Example 10.

[0039] Figure 9 These are plate photos and survival rate comparison charts of E. coli incubated under different conditions in Experiment Example 1.

[0040] Figure 10 These are plate photographs and survival rate comparison charts of Staphylococcus aureus incubated under different conditions in Experiment Example 2.

[0041] Figure 11 This is a cytotoxicity test diagram of the biomass-based carbon-supported transition metal single-atom catalyst prepared in Example 1. Detailed Implementation

[0042] The technical solution of this application will be clearly and completely described below through specific embodiments. Obviously, the following embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention should be considered as equivalent substitutions and are included within the protection scope of the present invention.

[0043] All raw materials used in the following examples are commercially available products of analytical grade.

[0044] Example 1

[0045] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst, comprising the following steps:

[0046] 2.0 g of biomass (lignin) and 1.0 g of zinc acetate were mixed in 500 mL of deionized water and stirred at room temperature for 2 h. The mixture was then allowed to stand at room temperature for 12 h to age, followed by centrifugation at 3000 r / min for 4 min. The precipitate was collected and dried at 80 °C for 12 h to obtain a biomass-zinc precursor. Next, 1.0 g of the biomass-zinc precursor was ground and mixed with 10 g of urea for 20 min. The mixture was placed in a tube furnace, purged with nitrogen at a flow rate of 50 mL / min, and annealed at 800 °C for 2 h. After natural cooling to room temperature, a biomass-based carbon-supported transition metal single-atom catalyst was obtained.

[0047] The SEM image of the biomass-based carbon-supported transition metal single-atom catalyst prepared in this embodiment is shown below. Figure 1 As shown.

[0048] Depend on Figure 1It can be seen that the prepared biomass-based carbon-supported transition metal single-atom catalyst exhibits a wrinkled nanosheet structure.

[0049] TEM image of the biomass-based carbon-supported transition metal single-atom catalyst prepared in this embodiment is shown below. Figure 2 As shown.

[0050] Depend on Figure 2 It can be seen that the prepared biomass-based carbon-supported transition metal single-atom catalyst is a thin sheet with abundant pores.

[0051] The elemental distribution diagram of the biomass-based carbon-supported transition metal single-atom catalyst prepared in this embodiment is shown in the figure below. Figure 3 As shown.

[0052] Depend on Figure 3 It can be seen that the transition metal zinc was successfully loaded and uniformly distributed in the prepared biomass-based carbon-supported transition metal single-atom catalyst.

[0053] The XRD pattern of the biomass-based carbon-supported transition metal single-atom catalyst prepared in this embodiment is as follows: Figure 4 As shown.

[0054] Depend on Figure 4 It can be seen that the prepared biomass-based carbon-supported transition metal single-atom catalyst does not contain zinc in the metal phase.

[0055] The HAADF-STEM image of the biomass-based carbon-supported transition metal single-atom catalyst prepared in this embodiment is shown below. Figure 5 As shown.

[0056] Depend on Figure 5 It can be seen that no zinc particles are present in the prepared biomass-based carbon-supported transition metal single-atom catalyst, and the zinc element is atomically dispersed in the carbon framework.

[0057] The N2 adsorption-desorption isotherms and pore size distribution of the biomass-based carbon-supported transition metal single-atom catalyst prepared in this embodiment are shown in the figure below. Figure 6 As shown.

[0058] Depend on Figure 6 It can be seen that the specific surface area of ​​the prepared biomass-based carbon-supported transition metal single-atom catalyst is as high as 480 m². 2 / g, has a rich layered porous structure of micropores, mesopores and macropores.

[0059] The loading of transition metal single atoms was 3.30 wt%.

[0060] Example 2

[0061] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is described in Example 1, except that cellulose is used instead of lignin; other steps and conditions are the same as in Example 1. The transition metal single-atom loading is 2.1 wt%, and it is uniformly dispersed in the biomass-based carbon support in single-atom form without agglomeration.

[0062] Example 3

[0063] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is described in Example 1, except that hemicellulose is used instead of lignin; other steps and conditions are the same as in Example 1. The transition metal single-atom loading is 1.4 wt%, and it is uniformly dispersed in the biomass-based carbon support in single-atom form without agglomeration.

[0064] Example 4

[0065] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that 10 g of zinc acetate is used instead of 1.0 g of zinc acetate; the other steps and conditions are the same as in Example 1.

[0066] The HAADF-STEM image of the biomass-based carbon-supported transition metal single-atom catalyst prepared in this embodiment is shown below. Figure 7 As shown.

[0067] Depend on Figure 7 It can be seen that in the prepared biomass-based carbon-supported transition metal single-atom catalyst, the zinc element is uniformly dispersed in the biomass-based carbon support in the form of single atoms, accompanied by a uniformly distributed agglomerated state.

[0068] The single-atom loading of transition metals was 3.9 wt%.

[0069] Example 5

[0070] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that cyanamide is used instead of urea; the other steps and conditions are the same as in Example 1.

[0071] Example 6

[0072] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that ethylenediamine is used instead of urea; the other steps and conditions are the same as in Example 1.

[0073] Example 7

[0074] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that polyethyleneimine is used instead of urea; the other steps and conditions are the same as in Example 1.

[0075] Example 8

[0076] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is described in Example 1, except that dicyandiamide is used instead of urea; other steps and conditions are the same as in Example 1. The transition metal single-atom loading is 2.2 wt%, and it is uniformly dispersed in the biomass-based carbon support in single-atom form without agglomeration.

[0077] Example 9

[0078] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that melamine is used instead of urea; the other steps and conditions are the same as in Example 1.

[0079] Example 10

[0080] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the calcination temperature is 700°C; other steps and conditions are the same as in Example 1.

[0081] The HAADF-STEM image of the biomass-based carbon-supported transition metal single-atom catalyst prepared in this embodiment is shown below. Figure 8 As shown.

[0082] Depend on Figure 8 It can be seen that in the prepared biomass-based carbon-supported transition metal single-atom catalyst, the zinc element is uniformly dispersed in the biomass-based carbon support in the form of single atoms, accompanied by a uniformly distributed agglomerated state.

[0083] The single-atom loading of the transition metal was 4.9 wt%.

[0084] Example 11

[0085] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the calcination time is 1 hour; other steps and conditions are the same as in Example 1.

[0086] Example 12

[0087] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the calcination time is 3 hours; other steps and conditions are the same as in Example 1.

[0088] Example 13

[0089] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the calcination time is 4 hours; other steps and conditions are the same as in Example 1.

[0090] Example 14

[0091] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the gas flow rate is 30 mL / min; the other steps and conditions are the same as in Example 1.

[0092] Example 15

[0093] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the gas flow rate is 40 mL / min; the other steps and conditions are the same as in Example 1.

[0094] Example 16

[0095] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the gas flow rate is 60 mL / min; the other steps and conditions are the same as in Example 1.

[0096] Example 17

[0097] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the gas flow rate is 70 mL / min; the other steps and conditions are the same as in Example 1.

[0098] Example 18

[0099] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the gas flow rate is 80 mL / min; the other steps and conditions are the same as in Example 1.

[0100] Example 19

[0101] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that zinc nitrate is used instead of zinc acetate in the same molar amount; the other steps and conditions are the same as in Example 1.

[0102] Example 20

[0103] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that zinc chloride is used instead of zinc acetate in the same molar amount; the other steps and conditions are the same as in Example 1.

[0104] Example 21

[0105] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the same molar amount of manganese nitrate is used instead of zinc acetate; the other steps and conditions are the same as in Example 1.

[0106] Example 22

[0107] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the same molar amount of manganese chloride is used instead of zinc acetate; the other steps and conditions are the same as in Example 1.

[0108] Example 23

[0109] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst (N / C-20-1000℃) is as described in Example 1, except that manganese acetate is used instead of zinc acetate in the same molar amount; other steps and conditions are the same as in Example 1. The transition metal single-atom loading is 3.2 wt%, and it is uniformly dispersed in the biomass-based carbon support in single-atom form without agglomeration.

[0110] Example 24

[0111] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the same molar amount of copper chloride is used instead of zinc acetate; the other steps and conditions are the same as in Example 1.

[0112] Example 25

[0113] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the same molar amount of copper nitrate is used instead of zinc acetate; the other steps and conditions are the same as in Example 1.

[0114] Example 26

[0115] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that copper acetate is used instead of zinc acetate in the same molar amount; the other steps and conditions are the same as in Example 1.

[0116] Example 27

[0117] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst (N / C-10) is as described in Example 1, except that nickel acetate is used instead of zinc acetate in the same molar amount; the other steps and conditions are the same as in Example 1.

[0118] Example 28

[0119] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the same molar amount of nickel nitrate is used instead of zinc acetate; the other steps and conditions are the same as in Example 1.

[0120] Example 29

[0121] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the same molar amount of nickel chloride is used instead of zinc acetate; the other steps and conditions are the same as in Example 1.

[0122] Example 30

[0123] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that cobalt acetate is used instead of zinc acetate in the same molar amount; the other steps and conditions are the same as in Example 1.

[0124] Example 31

[0125] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that cobalt sulfate is used instead of zinc acetate in the same molar amount; the other steps and conditions are the same as in Example 1.

[0126] Example 32

[0127] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that cobalt nitrate is used instead of zinc acetate in the same molar amount; the other steps and conditions are the same as in Example 1.

[0128] Example 33

[0129] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that cobalt chloride is used instead of zinc acetate in the same molar amount; the other steps and conditions are the same as in Example 1.

[0130] Example 34

[0131] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that ferric chloride is used instead of zinc acetate in the same molar amount; the other steps and conditions are the same as in Example 1.

[0132] Example 35

[0133] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that the same molar amount of ferric nitrate is used instead of zinc acetate; the other steps and conditions are the same as in Example 1.

[0134] Example 36

[0135] A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst is as described in Example 1, except that ferrous chloride is used instead of zinc acetate in the same molar amount; the other steps and conditions are the same as in Example 1.

[0136] Experiment 1: Antibacterial Performance Test of Escherichia coli

[0137] Antibacterial performance test on Escherichia coli

[0138] (1) Inoculate Escherichia coli into LB medium and culture on a shaker at 37°C and 180 r / min for 12 h. Dilute the bacterial suspension to determine the concentration of the bacterial suspension as 10. 7 CFU / mL. Take 10 mL of diluted Escherichia coli culture and add aqueous solutions of biomass-based carbon-supported transition metal single-atom catalysts prepared in Example 1 at different concentrations. Incubate in a shaker at 37°C and 180 r / min for 4 h. Take 200 μL of the culture and spread it on LB solid medium. Incubate in a constant temperature incubator at 37°C for 12 h and count the colonies on the plate.

[0139] The survival rate of *E. coli* was calculated to evaluate its antibacterial performance; the colony count on the plate of the control group was recorded as A0, and the colony count on the plate of the sample was recorded as A... t The survival rate of E. coli is calculated using the following formula: Survival rate (%) = A t / A0×100%.

[0140] Figure 9 These are plate photos and survival rate comparison charts of E. coli incubated under different conditions in Experiment Example 1.

[0141] Depend on Figure 9 It can be seen that the biomass-based carbon-supported transition metal single-atom catalyst prepared in Example 1 (the concentration of the catalyst in the whole culture system is 10 μg / mL) has a bactericidal rate of >99.9% against Escherichia coli.

[0142] Further testing revealed that the minimum inhibitory concentration (MIC) of the biomass-based carbon-supported transition metal single-atom catalyst prepared in Example 1 against Escherichia coli was 10 μg / mL.

[0143] Experiment Example 2: Antibacterial Performance Test of Staphylococcus aureus

[0144] The test method for the antibacterial performance against Staphylococcus aureus is as described in Test Example 1.

[0145] Figure 10 These are plate photographs and survival rate comparison charts of Staphylococcus aureus incubated under different conditions in Experiment Example 2.

[0146] Depend on Figure 10 It can be seen that the biomass-based carbon-supported transition metal single-atom catalyst prepared in Example 1 (the concentration of the catalyst in the whole culture system is 10 μg / mL) has a bactericidal rate of >99.9% against Staphylococcus aureus.

[0147] Further testing revealed that the minimum inhibitory concentration (MIC) of the biomass-based carbon-supported transition metal single-atom catalyst prepared in Example 1 against Staphylococcus aureus was 10 μg / mL.

[0148] Experimental Example 3: Cytotoxicity Test

[0149] The biomass-based carbon-supported transition metal single-atom catalyst from Example 1 was used to perform cytotoxicity tests on HeLa cells.

[0150] HeLa cells were incubated at 37°C for 24 h with aqueous solutions of biomass-based carbon-supported transition metal single-atom catalysts prepared in Example 1 at concentrations ranging from 0 to 200 μg / mL. Then, 200 mL of fresh culture medium containing 20 mL of MTT (5 mg / mL in PBS) was added, and the cells were incubated at 37°C for 4 h. Finally, 150 mL of DMSO was added to dissolve the formed purple formazan crystals. The optical density was measured at 570 nm using a microplate reader, with pure DMSO used as a blank. Cytotoxicity after each treatment was expressed as a percentage of cell viability relative to untreated control cells.

[0151] Figure 11 This is a cytotoxicity test diagram of the biomass-based carbon-supported transition metal single-atom catalyst prepared in Example 1.

[0152] Depend on Figure 11 It can be seen that the biomass-based carbon-supported transition metal single-atom catalyst prepared in Example 1 is almost non-toxic to HeLa cells.

Claims

1. A biomass-based carbon-supported transition metal single-atom catalyst, characterized in that, The catalyst is a transition metal uniformly loaded onto biomass-based carbon in the form of single atomic sites.

2. The biomass-based carbon-supported transition metal single-atom catalyst according to claim 1, characterized in that, The microstructure of the biomass-based carbon-supported transition metal single-atom catalyst is: a pleated nanosheet with a porous structure.

3. The biomass-based carbon-supported transition metal single-atom catalyst according to claim 1, characterized in that, The specific surface area of ​​biomass-based carbon-supported transition metal single-atom catalysts is 400-500 m². 2 / g.

4. The biomass-based carbon-supported transition metal single-atom catalyst according to claim 1, characterized in that, The loading of transition metal single atoms in the biomass-based carbon-supported transition metal single-atom catalyst is 0.20 wt% to 4.90 wt%.

5. A method for preparing a biomass-based carbon-supported transition metal single-atom catalyst as described in any one of claims 1-4, comprising the following steps: (1) Biomass and transition metal salts are fully dispersed in deionized water, aged, centrifuged and dried to obtain biomass-transition metal precursor; (2) The biomass-transition metal precursor and nitrogen source are ground and mixed evenly, and then calcined to obtain a biomass-based carbon-supported transition metal single-atom catalyst.

6. The method for preparing the biomass-based carbon-supported transition metal single-atom catalyst according to claim 5, characterized in that, In step (1), the biomass is selected from carbon-containing biomass in nature; preferably, the biomass is selected from one or more combinations of lignin, cellulose or hemicellulose extracted from rice husks, bamboo leaves, straw, leaves or wood.

7. The method for preparing the biomass-based carbon-supported transition metal single-atom catalyst according to claim 5, characterized in that, In step (1), the transition metal salt is at least one of soluble iron salt, soluble cobalt salt, soluble nickel salt, soluble copper salt, soluble manganese salt, or soluble zinc salt; preferably, the transition metal salt is at least one of ferrous chloride, ferric nitrate, ferric chloride, cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, nickel chloride, nickel nitrate, nickel acetate, copper acetate, copper chloride, copper nitrate, manganese acetate, manganese chloride, manganese nitrate, zinc chloride, zinc acetate, or zinc nitrate.

8. The method for preparing the biomass-based carbon-supported transition metal single-atom catalyst according to claim 5, characterized in that, Step (1) includes one or more of the following conditions: i. The mass ratio of biomass to transition metal salt is 0.2-10:1; ii. The mass ratio of biomass to deionized water is 0.1-10:250; iii. Stir at room temperature for 0.5–3 hours to ensure full dispersion; aging time is 6–24 hours, and aging is carried out under static conditions at room temperature; centrifugation speed is 3000–5000 r / min, and centrifugation time is 1–5 min; drying temperature is 50–80℃, and drying time is 10–24 hours.

9. The method for preparing the biomass-based carbon-supported transition metal single-atom catalyst according to claim 5, characterized in that, Step (2) includes one or more of the following conditions: i. The nitrogen source is at least one selected from 1,2,4,5-tetraaminobenzene, urea, ammonium nitrate, p-phenylenediamine, 4,4'-bipyridine, cyanamide, ethylenediamine, polyethyleneimine, dicyandiamide, or melamine; preferably, the nitrogen source is at least one selected from urea, cyanamide, ethylenediamine, polyethyleneimine, dicyandiamide, or melamine. ii. The mass ratio of biomass-transition metal precursor to nitrogen source is 1:1-30; iii. The grinding and mixing time is 10-30 minutes; iv. The calcination is carried out under a protective gas, which is one of nitrogen, argon or a nitrogen-argon mixture, with a flow rate of 30-80 mL / min; the calcination temperature is 700-800℃, and the calcination time is 1-4 h.

10. The use of the biomass-based carbon-supported transition metal single-atom catalyst as described in any one of claims 1-4 in antibacterial applications or in the preparation of antibacterial drugs or dressings; Preferably, the biomass-based carbon-supported transition metal single-atom catalyst is used for the bactericidal or bacteriostatic effects on Escherichia coli and / or Staphylococcus aureus.

Images