Heteroatom-doped carbon-supported single-atom material, method for preparing same, and use thereof

Abstract

The application provides a heteroatom-doped carbon loaded monatomic material, a preparation method and application thereof. The preparation method comprises the following steps: doping a heteroatom into a metal organic framework to obtain heteroatom-doped carbon; and doping a monatomic into the heteroatom-doped carbon to obtain the heteroatom-doped carbon loaded monatomic material. The heteroatom-doped carbon loaded monatomic material obtained by using the above preparation method can effectively inhibit stomatal closure of plants under strong light stress, optimize photosynthesis and water use efficiency of the plants, and improve adversity adaptability and yield of crops, which has important significance for food security.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nanomaterials, in particular to a heteroatom-doped carbon-supported monatomic material, a preparation method and application thereof. BACKGROUND

[0002] Abiotic stress such as drought, salinity, high temperature and strong light in agricultural production poses a serious challenge to the growth of crops, directly affecting the yield and quality of food. Traditional agricultural techniques (e.g., genetic breeding, water and fertilizer management, and field management measures) have their application value, but there are still many deficiencies in dealing with these environmental pressures. Therefore, it is of great importance to explore and develop new stress-resistant technologies to improve the environmental adaptability of plants to ensure global food security.

[0003] In recent years, nanotechnology has shown great application potential in the field of agriculture, especially in the field of plant stress resistance. The emergence of nano-pesticides, combined with nanotechnology and modern agriculture, not only strengthens the efficacy, reduces the usage amount, and reduces the potential harm to the environment, but also improves the stability and persistence.

[0004] The development and application of nano-pesticides depend on the characteristics and functions of nanomaterials. Compared with traditional nanomaterials, monatomic materials have obvious advantages in catalytic efficiency and stability due to their high-density active centers and precise active site structure. However, the potential of monatomic materials in regulating plant physiological processes has not been fully explored. The existing nano-pesticides on the market do not fully utilize the excellent characteristics of monatomic materials, especially in the application of promoting stomatal opening of plants under strong light stress.

[0005] Therefore, the development of a monatomic material that promotes stomatal opening of plants under strong light stress and further enhances the stress resistance of crops will greatly enrich the types of nano-pesticides, expand the application boundary of monatomic materials in the field of agriculture, and has far-reaching significance for improving the adaptability and yield of crops. SUMMARY

[0006] The main purpose of the present application is to provide a heteroatom-doped carbon-supported monatomic material, a preparation method and application thereof, to solve the problem of lack of monatomic materials that promote stomatal opening of plants under strong light stress in the prior art.

[0007] In order to achieve the above-mentioned purpose, according to the first aspect of the present application, a preparation method of a heteroatom-doped carbon-supported monatomic material is provided, which comprises:

[0008] doping a heteroatom into a metal-organic framework to obtain heteroatom-doped carbon; doping a monatomic atom into the heteroatom-doped carbon to obtain a heteroatom-doped carbon-supported monatomic material.

[0009] Furthermore, the above-mentioned doping includes the steps of mixing and heating under an inert gas atmosphere; wherein the above-mentioned mixing method is selected from ball milling or liquid phase stirring; the above-mentioned inert gas is selected from high-purity nitrogen or high-purity argon; and the flow rate of the above-mentioned inert gas is 50~200 mL / min.

[0010] Furthermore, the heating temperature is 300-1000° C., the heating time is 0.5-5 h, and the heating rate is 1-10° C. / min.

[0011] Furthermore, the heteroatom is derived from a heteroatom compound; the metal organic framework and the heteroatom compound are doped at a mass ratio of 0.5 to 5:1.

[0012] Furthermore, the heteroatom compound is selected from any one or more of the following: cysteine, trithiocyanate, thiourea, phytic acid, sodium phytate or 3,5-dicarboxyphenylboronic acid.

[0013] Furthermore, the metal organic framework is ZIF-8.

[0014] Furthermore, the atoms are derived from a single-atom precursor; and the heteroatom-doped carbon and the single-atom precursor are doped at a mass ratio of 1 to 15:1.

[0015] Furthermore, the above-mentioned single-atom precursor is selected from any one or more of the following: ferric nitrate, ferric chloride, hemin chloride, cobalt nitrate, nickel nitrate, copper nitrate, manganese chloride, selenium powder or selenium dioxide.

[0016] In order to achieve the above object, according to a second aspect of the present invention, there is provided a heteroatom-doped carbon-supported single-atom material prepared by the above-mentioned method for preparing the heteroatom-doped carbon-supported single-atom material.

[0017] To achieve the above object, according to a third aspect of the present invention, a heteroatom-doped carbon-supported single-atom material is provided, wherein the heteroatom-doped carbon-supported single-atom material comprises a heteroatom-doped carrier and an interface-modifying atom; the interface-modifying atom is uniformly dispersed in the form of single atoms and supported on the heteroatom-doped carrier;

[0018] Wherein, the above-mentioned heteroatom-doped carrier is selected from heteroatom-doped metal-organic framework.

[0019] Furthermore, the above-mentioned interface modification atoms are selected from any one or more of the following: Fe, Co, Cu, Ni, Mn or Se.

[0020] Furthermore, the content of the above-mentioned interface modification atoms in the above-mentioned heteroatom-doped carbon-supported single-atom material is 0.1-10 wt %.

[0021] Furthermore, the metal organic framework is ZIF-8.

[0022] Furthermore, the heteroatom is selected from any one or more of the following: N, O, S, P or B.

[0023] Furthermore, the content of heteroatoms in the heteroatom-doped carbon-supported single-atom material is 0.5-15 wt %.

[0024] In order to achieve the above-mentioned purpose, according to the fourth aspect of the present invention, a method for preparing the above-mentioned heteroatom-doped carbon-loaded single-atom material, or a heteroatom-doped carbon-loaded single-atom material prepared by the above-mentioned method for preparing the heteroatom-doped carbon-loaded single-atom material, or the use of the above-mentioned heteroatom-doped carbon-loaded single-atom material in promoting the opening of plant stomata under strong light stress is provided.

[0025] Applying the technical solution of the present invention, metal-organic frameworks are doped with heteroatoms and single atoms to produce heteroatom-doped carbon-loaded single-atom materials. This method, through a stepwise doping synthesis strategy, allows for flexible control of the type and doping composition of the single-atom center while maintaining the integrity of the original material morphology. Furthermore, the method has the beneficial effect of being easily mass-produced. The single-atom materials prepared using this method can inhibit stomatal closure induced by strong light stress, thereby improving plant stress resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0027] Figure 1 Transmission electron microscope images of the single-atom material prepared according to Example 1 of the present invention are shown, wherein a represents the single-atom material NCP; b represents the single-atom material Fe-NCP; and c represents the single-atom material FeSe-NCP.

[0028] Figure 2 The X-ray diffraction (XRD) patterns of the single-atom materials NCP, Fe-NCP, and FeSe-NCP prepared in Example 1 of the present invention are shown. The results show that all samples exhibit a consistent amorphous structure, and no characteristic peaks of Fe or Se are detected.

[0029] Figure 3 The energy dispersive X-ray spectroscopy element mapping (EDS Mapping) diagram of the single-atom materials Fe-NCP and FeSe-NCP prepared in Example 1 of the present invention is shown: the results show that Fe or Se, P, C, and N in the materials are uniformly distributed on the surface of the materials.

[0030] Figure 4The Fe K-edge of the single-atom materials Fe-NCP and FeSe-NCP prepared in Example 1 of the present invention is shown ( Figure 4 a) and Se K-edge ( Figure 4 Fourier transform X-ray absorption fine structure spectroscopy (FTXAS) in Figure b) shows the absence of Fe-Fe or Se-Se bonds in both materials, confirming that they are single-atom materials. Se-Fe coordination is observed in the Se K-edge of FeSe-NCP, confirming its dual single-atom nature.

[0031] Figure 5 Schematic diagrams of the structures of single-atom materials Fe-NCP and FeSe-NCP prepared according to Example 1 of the present invention are shown; first-principles calculations show that in FeSe-NCP, Fe coordinates with three N atoms and one Se atom to form a FeSe double single-atom structure; in Fe-NCP, Fe coordinates with four N atoms to form a Fe single-atom structure.

[0032] Figure 6A The figure shows a histogram of the atomic spacing distribution of the single-atom material FeSe-NCP prepared according to Example 1 of the present invention obtained by spherical aberration corrected high-angle annular dark field scanning transmission electron microscopy.

[0033] Figure 6B The atomic spacing distribution of the single-atom material Fe-NCP prepared according to Example 1 of the present invention is shown, which is obtained by spherical aberration-corrected high-angle annular dark-field scanning transmission electron microscopy.

[0034] Figure 7 The effects of single-atom materials NCP, Fe-NCP and FeSe-NCP prepared according to Example 1 of the present invention on the stomatal aperture of tobacco under strong light stress are shown; wherein, Mock represents water; the letters a, b and c represent the letter notation method for significant difference analysis, wherein the differences between groups with the same letters are not significant, and the differences between groups with different letters are significant.

[0035] Figure 8 The effects of single-atom materials NCP, Fe-NCP and FeSe-NCP prepared according to Example 1 of the present invention on the stomatal aperture of Arabidopsis thaliana under strong light stress are shown; wherein, Mock represents water; the letters a, b and c represent the letter notation method for significant difference analysis, wherein the differences between groups with the same letters are not significant, and the differences between groups with different letters are significant.

[0036] Figure 9 The effects of the single-atom materials NCP, Fe-NCP and FeSe-NCP prepared according to Example 1 of the present invention on the stomatal morphology of Arabidopsis thaliana under strong light stress are shown.

[0037] Figure 10The effects of the single-atom materials NCP, Fe-NCP and FeSe-NCP prepared according to Example 1 of the present invention on the growth state of Arabidopsis thaliana under strong light stress are shown.

[0038] Figure 11 The effects of single-atom materials NCP, Fe-NCP, and FeSe-NCP prepared according to Example 1 of the present invention on the aboveground fresh weight of Arabidopsis thaliana under strong light stress are shown; wherein, Mock represents water; the letters a, b, and c represent the letter notation method for significance difference analysis, wherein the differences between groups with the same letters are not significant, and the differences between groups with different letters are significant.

[0039] Figure 12 A diagram showing the effects of the single-atom materials Fe-NCP and FeSe-NCP prepared according to Example 1 of the present invention on the stomatal conductance of grape photosynthesis under strong light stress is shown; wherein, Mock represents water; Fe-NCP and FeSe-NCP represent the effects of the single-atom materials under normal light; Fe-NCP-H and FeSe-NCP-H represent the effects of the single-atom materials under strong light stress; the letters a, b, and c represent the letter notation method for significance difference analysis, wherein the differences between groups with the same letters are not significant, and the differences between groups with different letters are significant.

[0040] Figure 13 The effects of the single-atom materials Fe-NCP and FeSe-NCP prepared according to Example 1 of the present invention on the intercellular carbon dioxide concentration of grape photosynthesis under strong light stress are shown; wherein, Mock represents water; Fe-NCP and FeSe-NCP represent the effects of the single-atom materials under normal light; Fe-NCP-H and FeSe-NCP-H represent the effects of the single-atom materials under strong light stress; the letters a, b, and c represent the letter notation method for significance difference analysis, wherein the differences between groups with the same letters are not significant, and the differences between groups with different letters are significant.

[0041] Figure 14 The effects of the single-atom materials Fe-NCP and FeSe-NCP prepared according to Example 1 of the present invention on the photosynthetic rate of grape photosynthesis under strong light stress are shown; wherein, Mock represents water; Fe-NCP and FeSe-NCP represent the effects of the single-atom materials under normal light; Fe-NCP-H and FeSe-NCP-H represent the effects of the single-atom materials under strong light stress; the letters a, b, and c represent the letter notation method for significance difference analysis, wherein the differences between groups with the same letters are not significant, and the differences between groups with different letters are significant. DETAILED DESCRIPTION

[0042] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0043] Explanation of terms:

[0044] High-purity argon and high-purity nitrogen: argon and nitrogen with a purity of 99.999% (5N) or above.

[0045] Nanopesticides: refers to pesticide formulations with a size between 1 and 100 nanometers that are prepared using nanotechnology. These formulations usually contain active pesticide ingredients encapsulated in nanocarriers, such as nanoparticles, nanocapsules or nanotubes. The advantages of nanopesticides are that they can improve the efficiency of pesticides, reduce usage, reduce environmental impact, and may extend the duration of effectiveness and enhance the targeting effect on target pests. Nanocarriers can be inorganic materials, organic polymers or a composite material of the two. By controlling the release rate and improving the adhesion to the plant surface, nanopesticides can be distributed more precisely on crops, reducing the loss of pesticides in the environment and toxicity to non-target organisms.

[0046] Single-atom materials: A specialized class of nanomaterials in which active metal or nonmetal elements are dispersed as single atoms on the surface or within the pores of a support material (such as graphene, carbon nanotubes, or metal oxides). These materials are characterized by extremely high atomic utilization efficiency and unique catalytic properties, as each active atom is fully accessible to the reactants, eliminating the core-shell effect seen in traditional metal nanoparticles. The preparation of single-atom materials typically involves precisely controlled chemical processes to ensure the stability and activity of the single atoms. They exhibit enormous potential for application in diverse fields, including catalysis, chemical sensing, energy conversion and storage, and environmental remediation.

[0047] MOFs (Metal-Organic Frameworks) are a class of porous crystalline materials with high porosity and open metal sites. These materials are composed of metal ions or clusters (nodes) chemically linked to organic ligands, forming a three-dimensional network. MOFs are characterized by their highly tunable and flexible structure, allowing them to be designed with diverse properties based on the specific metal ions and organic ligands.

[0048] Doping refers to the process of intentionally introducing foreign atoms into a host material to alter or optimize its physical and chemical properties. In this context, it refers to a technique for enhancing material properties by introducing heteroatoms or single metal atoms into a carbon support.

[0049] K-edge: In X-ray absorption spectroscopy (XAS), the K-edge refers to the absorption edge associated with the excitation of an element's 1s electron. K-edge absorption occurs when the X-ray energy is high enough to excite an inner-shell 1s electron to a higher unoccupied energy level or ionize it into the vacuum. This absorption edge appears as a distinct transition in the spectrum and is an important tool for studying the local electronic structure and chemical environment of elements in a material. K-edges appear at different energy positions for different elements, depending on their atomic number. Analysis of the K-edge in Fourier transform X-ray absorption fine structure spectroscopy (FT-EXAFS) can provide information about the local structure surrounding an atom.

[0050] First-principles calculations: A computational method based on the fundamental laws of quantum mechanics (such as the Schrödinger equation) used to determine the electronic structure and atomic behavior of materials. The core computational framework relies solely on universal physical constants (such as electron mass and charge) and the atomic configuration of the system, eliminating the need for system-specific fitting parameters. To account for specific physical effects (such as weak intermolecular interactions), empirical corrections can be incorporated into the basic calculations.

[0051] As mentioned in the background art, adverse conditions such as drought, strong light and high temperature can cause plant stomata to close and photosynthesis to be hindered. Nanopesticides, as an emerging and effective way to improve crop resistance to stress, are expected to be used to solve the problem of plant stomatal closure induced by strong light stress. However, the prior art lacks nanopesticides that can effectively promote the opening of plant stomata under strong light stress. Since the development and application of nanopesticides rely on the characteristics and functions of nanomaterials and the higher catalytic activity and stability of single-atom materials compared to traditional nanomaterials, the inventors of the present invention have attempted to develop a single-atom material to promote the opening of plant stomata under strong light stress to help plants cope with adverse conditions and improve their resistance to stress, and thus proposed a series of protection schemes of the present invention.

[0052] In a first typical embodiment of the present invention, a method for preparing a heteroatom-doped carbon-supported single-atom material is provided.

[0053] The preparation method comprises: doping heteroatoms into a metal organic framework to obtain heteroatom-doped carbon; and doping single atoms into the heteroatom-doped carbon to obtain a heteroatom-doped carbon-loaded single atom material.

[0054] The preparation of single-atom materials using this method offers the advantage of ease of operation. Through a stepwise synthesis strategy, the type and doping composition of the single-atom center can be flexibly controlled while maintaining the integrity of the original material morphology. Furthermore, the single-atom materials prepared using this method can inhibit stomatal closure induced by strong light stress in plants, thereby helping to improve plant stress tolerance.

[0055] In a preferred embodiment of the present invention, the above-mentioned doping includes the steps of mixing and heating under an inert gas atmosphere; wherein the above-mentioned mixing method is selected from ball milling or liquid phase stirring; the above-mentioned inert gas is selected from high-purity nitrogen or high-purity argon; and the flow rate of the above-mentioned inert gas is 50~200mL / min.

[0056] The mixing method described above allows for a more uniform mixing of the metal-organic framework and heteroatoms, as well as the heteroatom-doped carbon and single atoms. The inert gas flow rate described above protects the material from oxidation during high-temperature heating, resulting in stable properties of the prepared heteroatom-doped carbon-loaded single-atom material.

[0057] In a preferred embodiment of the present invention, the heating temperature is 300-1000° C., the heating time is 0.5-5 h, and the heating rate is 1-10° C. / min.

[0058] The above heating conditions help maintain the microstructure of the material and prevent the loss of active sites caused by excessive sintering, making the material have better biocompatibility and targeting.

[0059] In a preferred embodiment of the present invention, the heteroatoms are derived from a heteroatom compound; the metal-organic framework is doped with the heteroatom compound at a mass ratio of 0.5 to 5:1. This ratio achieves optimal heteroatom distribution, improving the electronic conductivity and chemical stability of the material. In a more preferred embodiment of the present invention, the metal-organic framework is doped with the heteroatom compound at a mass ratio of 1:1.

[0060] In a preferred embodiment of the present invention, the heteroatom compound is selected from any one or more of the following: cysteine, thiocyanate, thiourea, phytic acid, sodium phytate, or 3,5-dicarboxyphenylboronic acid. The introduction of heteroatoms has the beneficial effects of adjusting the electronic structure of the single-atom center, optimizing the adsorption behavior of reaction intermediates, and promoting enzyme-like reactions. In a more preferred embodiment of the present invention, the heteroatom compound is sodium phytate.

[0061] In a preferred embodiment of the present invention, the metal-organic framework is ZIF-8. ZIF-8 has high porosity and a stable framework structure. The nitrogen-doped carbon structure formed after pyrolysis of ZIF-8 helps stabilize single atomic sites and prevent metal agglomeration.

[0062] In a preferred embodiment of the present invention, the single atoms are derived from a single-atom precursor; the heteroatom-doped carbon and the single-atom precursor are doped in a mass ratio of 1 to 15:1. By adjusting this ratio, the metal content of the material can be finely controlled, thereby affecting its catalytic activity and selectivity. In a more preferred embodiment of the present invention, the heteroatom-doped carbon and the single-atom precursor are doped in a mass ratio of 10:1.

[0063] It should be noted that when multiple single atoms are to be doped, they cannot be doped simultaneously. Instead, one type of single atom is first doped to obtain an intermediate, which is then doped with another type of single atom, and so on. In a preferred embodiment of the present invention, the mass ratio of the intermediate to the other single atom precursor is 1 to 15:1. In a more preferred embodiment of the present invention, the mass ratio of the intermediate to the other single atom precursor is 10:1.

[0064] In a preferred embodiment of the present invention, the single-atom precursor is selected from any one or more of the following: ferric nitrate, ferric chloride, hemin, cobalt nitrate, nickel nitrate, copper nitrate, manganese chloride, selenium powder, or selenium dioxide. The introduction of the single-atom precursor has the beneficial effect of providing active sites. In a more preferred embodiment of the present invention, the single-atom precursor is hemin and, optionally, selenium dioxide.

[0065] When doping with multiple single atoms, the order of doping is determined based on practical needs (to effectively reduce the occurrence of single-atom agglomeration). In a preferred embodiment of the present invention, the single-atom precursors are hemin chloride and selenium dioxide; the doping order is: first doping with selenium dioxide to obtain an intermediate, and then doping the intermediate with hemin chloride.

[0066] It should be noted that, depending on the heteroatom or single atom introduced, the heating operation in the aforementioned doping step can be performed in a single or multiple times. For example, when introducing Se, heating is performed in two steps: first, heating to a lower temperature and holding for a period of time, and then heating to a higher temperature. When introducing Fe, only one heating step is required. The advantage of this is that the doping element is stably present in the material in the form of a single atom, thereby effectively reducing the occurrence of agglomeration.

[0067] In a second exemplary embodiment of the present invention, a heteroatom-doped carbon-supported single-atom material prepared using the aforementioned method for preparing a heteroatom-doped carbon-supported single-atom material is provided. This single-atom material can promote the opening of plant stomata under intense light stress, improve photosynthesis efficiency, accelerate plant growth, and contribute to increased crop yield and quality, while also reducing the use of chemical fertilizers and protecting the ecological environment.

[0068] In a third typical embodiment of the present invention, a heteroatom-doped carbon-loaded single-atom material is provided, wherein the heteroatom-doped carbon-loaded single-atom material includes a heteroatom-doped carrier and an interface-modified atom; the interface-modified atom is uniformly dispersed in the form of a single atom and loaded on the heteroatom-doped carrier; wherein the heteroatom-doped carrier is selected from a heteroatom-doped metal-organic framework.

[0069] In a preferred embodiment of the present invention, the interface modifier atoms are selected from any one or more of the following: Fe, Co, Cu, Ni, Mn, or Se. In a preferred embodiment of the present invention, the content of the interface modifier atoms in the heteroatom-doped carbon-supported single-atom material is 0.1-10 wt%. This content of interface modifier atoms ensures that the active sites are completely dispersed in the form of single atoms, preventing atomic agglomeration.

[0070] It should be noted that when there are multiple interface modifying atoms, the multiple interface modifying atoms are uniformly dispersed in the form of single atoms and supported on the heteroatom-doped carrier. For example, when the interface modifying atoms are Fe and Se, both Fe and Se are uniformly dispersed in the form of single atoms and supported on the heteroatom-doped carrier. The resulting single-atom material is called a double single-atom material.

[0071] In a preferred embodiment of the present invention, the above-mentioned interface modification atoms come from a single-atom precursor, and the above-mentioned single-atom precursor is selected from any one or more of the following: ferric nitrate, ferric chloride, hemin chloride, cobalt nitrate, nickel nitrate, copper nitrate, manganese chloride, selenium powder or selenium dioxide.

[0072] In a preferred embodiment of the present invention, the metal organic framework is ZIF-8.

[0073] In a preferred embodiment of the present invention, the heteroatom is selected from any one or more of the following: N, O, S, P or B. In a preferred embodiment of the present invention, the content of the heteroatom in the heteroatom-doped carbon-supported single-atom material is 0.5-15 wt%.

[0074] The use of this content of heteroatoms can effectively regulate the electronic structure of the active site while avoiding carrier distortion. In a preferred embodiment of the present invention, the heteroatoms are derived from heteroatom compounds, and the heteroatom compounds are selected from any one or more of the following: cysteine, trithiocyanate, thiourea, phytic acid, sodium phytate, or 3,5-dicarboxyphenylboronic acid.

[0075] In a preferred embodiment of the present invention, the metal-organic framework is ZIF-8; the heteroatom is P; and the interface-modifying atoms are Fe and Se. In a more preferred embodiment of the present invention, the P atom content in the heteroatom-doped carbon-supported single-atom material is 1.08 wt %; the Fe atom content in the heteroatom-doped carbon-supported single-atom material is 0.80 wt %; and the Se atom content in the heteroatom-doped carbon-supported single-atom material is 3.15 wt %.

[0076] In another preferred embodiment of the present invention, the metal-organic framework is ZIF-8, the heteroatom is P, and the interface-modifying atom is Fe. In a more preferred embodiment of the present invention, the P atom content in the heteroatom-doped carbon-supported single-atom material is 1.9 wt %, and the Fe atom content in the heteroatom-doped carbon-supported single-atom material is 0.80 wt %.

[0077] In a fourth typical embodiment of the present invention, a method for preparing the above-mentioned heteroatom-doped carbon-loaded single-atom material, or a single-atom material prepared using the above-mentioned method for preparing the heteroatom-doped carbon-loaded single-atom material, or the use of the above-mentioned heteroatom-doped carbon-loaded single-atom material in promoting the opening of plant stomata under strong light stress is provided.

[0078] In a preferred embodiment of the present invention, the light intensity of the strong light stress is: 150 μmol∙m -2 ∙s⁻¹ <light intensity ≤ 1500 μmol∙m -2 The above-mentioned plants include but are not limited to tobacco (Nicotiana benthamiana), Arabidopsis thaliana (Arabidopsis thaliana) and grape (Vitis vinifera L.), and any other plants are also suitable for the present invention.

[0079] The present invention is further described in detail below with reference to specific examples. These examples should not be construed as limiting the scope of protection claimed in the present invention.

[0080] Example 1

[0081] This embodiment provides a method for preparing a heteroatom-doped carbon-loaded single-atom material.

[0082] 1) ZIF-8 and sodium phytate were mixed in a 1:1 mass ratio and ball-milled for 20 minutes. The resulting powder was placed in a tube furnace and filled with high-purity argon at a flow rate of 50 mL / min. The tube furnace was heated to 900°C at a rate of 2°C / min, held for 3 hours, and then cooled to room temperature. The resulting product was washed three times with deionized water and ethanol and dried in a vacuum at 80°C to obtain N- and P-doped carbon (NCP).

[0083] 2) The NCP powder obtained in step 1) was mixed with selenium dioxide at a mass ratio of 1:1 and ball-milled for 20 minutes. The resulting powder was placed in a tube furnace and filled with high-purity argon at a flow rate of 50 mL / min. The tube furnace was heated to 300°C at a rate of 5°C / min, held at this temperature for 0.5 h, then to 950°C at a rate of 5°C / min, held at this temperature for 1 h, and then cooled to room temperature. This yielded N- and P-doped carbon-supported Se single atoms (Se-NCP).

[0084] 3) The powdered NCP (50 mg) and hemin obtained in step 1) were added to 25 mL of DMF at a mass ratio of 10:1, respectively, and ultrasonically dispersed for 1–2 h. The hemin-containing DMF solution was added dropwise to the NCP-containing DMF solution and stirred for 24 h. The product was collected by centrifugation at 11,000 rpm for 3 min. The resulting product was washed three times with DMF and dried under vacuum at 80°C. The dried powder was placed in a tube furnace and filled with high-purity argon at a flow rate of 50 mL / min. The tube furnace was heated to 800°C at a rate of 2°C / min, held at this temperature for 3 h, and then cooled to room temperature to obtain N- and P-doped carbon-supported Fe single atoms (Fe-NCP).

[0085] 4) The powdered materials Se-NCP (50 mg) and hemin obtained in step 2) were added to 25 mL of DMF at a mass ratio of 10:1, respectively, and ultrasonically dispersed for 1 hour. The hemin-containing DMF solution was added dropwise to the Se-NCP-containing DMF solution and stirred for 24 hours. The product was collected by centrifugation at 11,000 rpm for 3 minutes. The resulting product was washed three times with DMF and dried under vacuum at 80°C. The dried powder was placed in a tube furnace and filled with high-purity argon at a flow rate of 50 mL / min. The tube furnace was heated to 800°C at a rate of 2°C / min, maintained at this temperature for 3 hours, and then cooled to room temperature to obtain N- and P-doped carbon-supported Fe and Se diatoms (FeSe-NCP).

[0086] Figure 1 a, b and c are transmission electron microscope (TEM) images of NCP, Fe-NCP and FeSe-NCP in Example 1, respectively. Figure 1 As shown, the heteroatom-doped carbon support-loaded single-atom material obtained in this embodiment exhibits a concave dodecahedron configuration with an average diameter of about 250 nm, without obvious metal particles and morphological changes.

[0087] Figure 2The X-ray diffraction (XRD) patterns of the single-atom materials NCP, Fe-NCP, and FeSe-NCP show that all of these single-atom materials exhibit a consistent amorphous structure, with no characteristic peaks of Fe or Se detected.

[0088] Figure 3 Energy dispersive X-ray spectroscopy elemental mapping (EDSMapping) images of the single-atom materials Fe-NCP and FeSe-NCP show that Fe or Se, P, C, and N are uniformly distributed on the surface of the materials.

[0089] Figure 4 It is the Fe K edge of the single-atom materials Fe-NCP and FeSe-NCP ( Figure 4 a) and Se K-edge ( Figure 4 Fourier transform X-ray absorption fine structure spectra (b) show the absence of Fe-Fe or Se-Se bonds in all three materials, confirming that they are all single-atom materials. Se-Fe coordination is observed in the Se K-edge of FeSe-NCP, confirming its dual single-atom nature.

[0090] Figure 5 This is a schematic diagram of the structure of the single-atom material FeSe-NCP. First-principles calculations show that in FeSe-NCP, Fe is coordinated with three N atoms and one Se atom, forming a FeSe double single-atom structure; in Fe-NCP, Fe is coordinated with four N atoms, forming a Fe single-atom structure.

[0091] Figure 6A This is an aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (ACHAADF-STEM) image of the single-atom material FeSe-NCP. Fe and Se single atoms are uniformly distributed on the heteroatom-doped carbon support.

[0092] Figure 6B This is an aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (ACHAADF-STEM) image of the single-atom material Fe-NCP. The Fe single atoms are uniformly distributed on the heteroatom-doped carbon support.

[0093] The composition of the resulting single-atom material was determined by inductively coupled plasma mass spectrometry. The results showed that the mass ratios of Fe and Se atoms in the FeSe-NCP single-atom material were 0.80 wt% and 3.15 wt%, respectively, and the mass ratio of P was 1.08 wt%. The mass ratio of Fe atoms in the Fe-NCP single-atom material was 0.8 wt%, and the mass ratio of P was 1.9 wt%.

[0094] Unless otherwise specified, the detection methods for various detections of monatomic materials in this embodiment are conventional detection methods in the art.

[0095] Example 2

[0096] The effects of single-atom materials on stomatal movement in tobacco plants under strong light stress were examined. The specific methods are as follows:

[0097] 1) Tobacco (Nicotiana benthamiana) leaf discs were treated with a 100 μg / mL suspension of three single-atom materials: NCP, Fe-NCP, and FeSe-NCP (dispersion medium: 5 mM KCl, 50 μM CaCl2, and 10 mM MES / Tris (pH 5.6)). The leaf discs were floated on the suspension and exposed to normal light (150 μmol∙m -2 ∙s⁻¹) and strong light (1500 μmol∙m -2 ∙s⁻¹) for 3 h;

[0098] 2) Observe and photograph the stomata of tobacco leaf discs using a microscope;

[0099] The experimental results are as follows Figure 7 As shown in Figure 3, Fe-NCP and FeSe-NCP significantly alleviated stomatal closure induced by strong light.

[0100] Example 3

[0101] The effect of single-atom materials on stomatal movement in Arabidopsis thaliana under strong light stress was tested using the same method as in Example 2.

[0102] The experimental results are as follows Figure 8-9 As shown in Figure 3, Fe-NCP and FeSe-NCP significantly alleviated stomatal closure induced by strong light.

[0103] Example 4

[0104] The effects of single-atom materials on the growth of Arabidopsis thaliana under strong light stress were tested. The specific method is as follows: Arabidopsis thaliana was subjected to normal (100 μmol∙m -2 ∙s⁻¹) light and bright light (600 μmol∙m -2 ∙s⁻¹) stress, the Arabidopsis thaliana was sprayed with 10 mL (100 ug / mL) of the single-atom material every three days, photographed, and the fresh weight of the aboveground part of the Arabidopsis thaliana was weighed.

[0105] The experimental results are as follows Figure 10-11As shown in the results, FeSe-NCP significantly alleviated the growth inhibition of plants induced by strong light stress.

[0106] Example 5

[0107] The effects of single-atom materials on the photosynthetic rate of grapes (Vitis vinifera L.) under strong light stress were examined. The specific methods are as follows:

[0108] The net CO2 assimilation rate (intercellular CO2 concentration), stomatal conductance, and net photosynthetic rate in grape leaves were recorded using the portable photosynthesis measurement system LI-6800 (Li-Cor). The measurement conditions were: temperature 24 °C, relative humidity 60%, CO2 concentration 400 μmol∙mol⁻¹ (air), and light intensity 150 μmol∙m -2 ∙s⁻¹ (red light: blue light = 9:1) and 1100 μmol∙m -2 ∙s⁻¹ (red light:blue light = 9:1). Measurements were performed in the morning (8:00-11:00).

[0109] The experimental results are as follows Figure 12-14 As shown in the figure, Fe-NCP and FeSe-NCP significantly alleviated the inhibition of strong light stress on grape photosynthesis.

[0110] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: the single-atom material prepared by the present invention can effectively promote the opening of plant stomata under adverse stress such as strong light, optimize the photosynthesis and water use efficiency of plants, improve the adverse adaptability and yield of crops, and make important contributions to food security. The present invention also reduces the amount of pesticides used, reduces environmental pollution, and promotes the sustainability of agricultural production. In addition, the present invention applies single-atom materials to the regulation of plant physiological processes for the first time, expands the application range of nanomaterials in the agricultural field, provides a new perspective for the cross-integration of nanotechnology with biological sciences and environmental sciences, and demonstrates significant economic and environmental benefits.

[0111] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing heteroatom-doped carbon-supported single-atom materials, characterized in that: The preparation method comprises: Doping heteroatoms into metal-organic frameworks to obtain heteroatom-doped carbon; doping single atoms into the heteroatom-doped carbon to obtain a heteroatom-doped carbon-loaded single atom material; Wherein, the doping includes the steps of mixing and heating under an inert gas atmosphere; Wherein, the mixing method is selected from ball milling or liquid phase stirring; the inert gas is selected from high-purity nitrogen or high-purity argon; the flow rate of the inert gas is 50-200 mL / min; The heating temperature is 300-1000°C, the heating time is 0.5-5h, and the heating rate is 1-10°C / min; The heteroatom comes from a heteroatom compound; the metal organic framework and the heteroatom compound are doped at a mass ratio of 0.5 to 5:1; The heteroatom compound is selected from sodium phytate; The metal organic framework is ZIF-8; The single atom comes from a single atom precursor, and the heteroatom doping carbon and the single atom precursor are doped in a mass ratio of 1 to 15:1; The single-atom precursor is selected from any one or more of the following: hemin or selenium dioxide.

2. A heteroatom-doped carbon-supported single-atom material prepared by the method for preparing a heteroatom-doped carbon-supported single-atom material according to claim 1.

3. The heteroatom-doped carbon-supported single-atom material according to claim 2, characterized in that: The heteroatom-doped carbon-supported single-atom material comprises a heteroatom-doped carrier and an interface-modified atom; the interface-modified atom is uniformly dispersed in the form of a single atom and supported on the heteroatom-doped carrier; Wherein, the heteroatom-doped carrier is selected from a heteroatom-doped metal-organic framework; The interface modification atom is selected from any one or more of the following: Fe or Se; The content of the interface modification atoms in the heteroatom-doped carbon-supported single-atom material is 0.1-10 wt %; The metal organic framework is ZIF-8; The heteroatom is selected from P; The content of the heteroatom in the heteroatom-doped carbon-supported single-atom material is 0.5-15 wt %.

4. The preparation method of the heteroatom-doped carbon-supported single-atom material according to claim 1 or the use of the heteroatom-doped carbon-supported single-atom material according to claim 2 or 3 in promoting stomatal opening in plants under strong light stress.

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