A sub-nanometer material and its preparation method

Abstract

The present invention provides a method for preparing sub-nano materials. The preparation method includes the following steps: (1) After primary ball milling of the bulk material, ball milling balls, and grinding aid material A, grinding aid material B is added to the ball milling system for secondary ball milling to obtain a ball milling product; (2) The ball milling product is mixed with a solvent and ultrasonicated to obtain the sub-nano materials; wherein, the average particle size of the grinding aid material A is larger than that of the grinding aid material B. The preparation method is a top-down preparation strategy. Through the synergistic effect of two physical methods, ball milling and ultrasonication, the bulk material is effectively broken, and finally sub-nano materials with uniform particle size are obtained; this method has the advantages of high efficiency, environmental protection, simple operation, and low cost, is suitable for large-scale production, and has good application prospects; at the same time, the sub-nano materials prepared by this method have high purity, good dispersibility, a yield of up to 18%, uniform particle size, and controllable size.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterials and relates to a sub-nanomaterial and a preparation method thereof. Background Art

[0002] Since the rise of nanoscience and technology at the end of the last century, nanoscience and technology have made great progress. Nanomaterials exhibit nanoscale effects different from bulk materials, including surface / edge effects and quantum confinement effects, etc. Due to the unique physical and chemical properties of nanomaterials, they have a wide range of applications in the fields of optics, optoelectronics, energy and catalysis, detection and sensing, biotherapy, and environmental governance.

[0003] The characteristic size plays a decisive role in the properties and functions of nanomaterials. As nanomaterials continue to develop in the direction of infinitesimal size, sub-nanomaterials have gradually attracted great interest. At present, the main method for preparing sub-nanomaterials is the bottom-up method. The bottom-up method mainly prepares sub-nanomaterials through solution synthesis, such as single-atom catalysts or chemical clusters, etc. For example, CN101502880B discloses a preparation method of sub-nanometer gold cluster molecules. Using chloroauric acid as a raw material, a gold nanocrystal solution is synthesized and reacted with an organic amine solution to obtain sub-nanometer gold cluster molecules. CN106861684B discloses a sub-nanometer rhodium catalyst supported on titanium oxide. The sub-nanometer catalyst is prepared by the deposition-precipitation method. An aqueous solution of a rhodium precursor is added dropwise to a suspension of a titanium oxide support under stirring conditions, and after reaction and a series of post-treatments, it is obtained.

[0004] CN108315771B discloses an electrochemical preparation method of sub-nanometer-sized copper particle electrocatalysts. The method includes pretreating a graphite foil to obtain a graphite foil doped with nitrogen and sulfur; using the graphite foil doped with nitrogen and sulfur as a working electrode, a platinum sheet as a counter electrode, and silver / silver chloride as a reference electrode, and obtaining sub-nanometer copper particles of different sizes through electrochemical deposition. CN110152656A discloses a preparation method of a sub-nanometer-sized platinum-gold alloy cocatalyst. The main catalyst, anatase titanium dioxide nanosheets, is prepared by the classical hydrothermal method, and then the sub-nanometer-sized platinum-gold alloy cocatalyst-supported titanium dioxide photocatalyst is prepared by the polymer ligand-assisted loading method.

[0005] However, when using the bottom-up method to prepare sub-nanomaterials, it is difficult to achieve 100% conversion of the raw materials in the chemical synthesis process. The obtained sub-nanomaterials inevitably contain unreacted raw material compounds or are loaded with various surfactants, resulting in low purity of the sub-nanomaterials and complex purification processes, which cannot meet the requirements of large-scale preparation and high-performance applications of sub-nanomaterials.

[0006] Therefore, there is an urgent need to study a simple, efficient and low-cost general method for preparing high-purity sub-nanomaterials, so as to accelerate their industrialization process. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a sub-nanomaterial and a preparation method thereof. Through the synergistic effect of two physical methods of ball milling and ultrasonic treatment, the present invention effectively crushes the bulk material, and finally obtains sub-nanomaterials with uniform particle size; this method has the advantages of high efficiency, environmental protection, simple operation and low cost, is suitable for large-scale production, and has good application prospects; at the same time, the sub-nanomaterials prepared by this method have high purity, good dispersibility, a yield of up to 18%, uniform particle size, and controllable size.

[0008] To achieve this purpose, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a preparation method of sub-nanomaterials, and the preparation method includes the following steps:

[0010] (1) After primary ball milling of the bulk material, ball milling balls and grinding aid material A, grinding aid material B is added to the ball milling system for secondary ball milling to obtain a ball milling product;

[0011] (2) Mix the ball milling product with a solvent and perform ultrasonic treatment to obtain the sub-nanomaterials;

[0012] Wherein, the average particle size of the grinding aid material A is larger than the average particle size of the grinding aid material B.

[0013] The present invention provides a preparation method of sub-nanomaterials, which is a top-down preparation strategy. Through the synergistic effect of two physical methods of ball milling and ultrasonic treatment, the bulk material is effectively crushed, and finally sub-nanomaterials with uniform particle size are obtained; during the ball milling process, the ball milling balls and the grinding aid material A can form a binary synergistic ball milling effect. In particular, the introduction of the grinding aid material A greatly increases the stress points acting on the bulk material (including transverse stress and normal stress), and generates a huge pressure under a very small contact area, thereby crushing the large block material into nanoscale; then, the grinding aid material B with a smaller particle size is introduced, which can make the ball milling balls, the grinding aid material A and the grinding aid material C form a ternary synergistic ball milling effect, and further crush the nanoscale material into sub-nanoscale.

[0014] This method has the advantages of high efficiency, environmental protection, simple operation and low cost, is suitable for large-scale production, and has good application prospects; at the same time, the sub-nanomaterials prepared by this method have high purity, good dispersibility, a yield of up to 18%, uniform particle size, and controllable size, which has important guiding significance for realizing industrial application and accelerating its industrialization process.

[0015] Preferably, the body material includes layered materials and / or non-layered materials.

[0016] Preferably, the layered material includes any one or a combination of at least two of graphite, boron nitride, black phosphorus (BP), g-C3N4, MoS2, MoSe2, MoTe2, WS2, WSe2, WTe2, TiS2, MnS2, FeS2, CoS2, NiS2, In2S3, In2Se3, In2Te3, Bi2Se3, Bi2Te3, Sb2Te3, Ti2C, Ti3C2, Ti4N3, V2C, Nb2C, Mo2C or Mo2TiC2.

[0017] Preferably, the non-layered material includes any one or a combination of at least two of metallic materials, inorganic semiconductor materials or organic semiconductor materials.

[0018] Preferably, the metal elements in the metallic material include any one or a combination of at least two of Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Ag, Cd, W, Pb, Pt, Au, Ge, Sn, Sb or Bi elements.

[0019] Preferably, the inorganic semiconductor material includes any one or a combination of at least two of IIIA-VA group compounds (such as GaAs), IIIA-VIA group compounds (such as In2S3), IVA-IVA group compounds (such as SiC), IVA-VA group compounds (such as Si3N4), IVA-VIA group compounds (such as SiO2), VA-VIA group compounds (Sb2Te3), oxides of transition elements (such as Cu, Zn, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Mo or W), Si-AlP, Ge-GaAs, InAs-InSb, AlSb-GaSb, InAs-InP, GaAs-GaP, ZnSiP2, ZnGeP2, ZnGeAs2, CdGeAs2, CdSnSe2, CuGaSe2, AgInTe2, AgTlTe2, CuInSe2, CuAlS2, Cu3AsSe4, Ag3AsTe4, Cu3SbS4, Ag3SbSe4 or Cu2FeSnS4, preferably any one or a combination of at least two of PbS, CdS, CuS, FeS, ZnS, PbSe, CdSe, CuSe, FeSe, ZnSe, PbTe, CdTe, CuTe, FeTe, ZnTe, GaN, InP, ZnO, TiO2, CdO, SiO2, Si3N4, SiC, GaAs, Cu3SbS4 or Ag3SbSe4.

[0020] Preferably, the organic semiconductor material includes any one or a combination of at least two of naphthalene, anthracene, polyacrylonitrile or phthalocyanine.

[0021] Preferably, the average particle size of the matrix material is 0.1 - 10000 μm, for example, it can be 0.1 μm, 0.2 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 50 μm, 100 μm, 200 μm, 400 μm, 600 μm, 800 μm, 1000 μm, 2000 μm, 4000 μm, 6000 μm, 6500 μm, 7000 μm, 7500 μm, 8000 μm, 9000 μm or 10000 μm, etc., and more preferably 0.5 - 1000 μm.

[0022] Preferably, the grinding aid material A and the grinding aid material B independently include any one or a combination of at least two of ionic compounds, metals, metal compounds, oxides or carbides, and are preferably oxides and / or carbides.

[0023] In the present invention, "independently" means that the selection of the types of the grinding aid material A and the grinding aid material B does not affect each other, and the types of the two can be the same or different. Exemplarily, the grinding aid material A can be selected from any one or a combination of at least two of ionic compounds, metals, metal compounds, oxides or carbides; the grinding aid material B can be selected from any one or a combination of at least two of ionic compounds, metals, metal compounds, oxides or carbides. In the present invention, the same applies to the rest of "independently".

[0024] Preferably, the cations of the ionic compound include cations of Group IA elements (such as Na + or K + etc.), cations of Group IIA elements (such as Mg 2+ , Ca 2+ or Ba 2+ etc.) or NH4 + or any one or a combination of at least two of them.

[0025] Preferably, the anions of the ionic compound include OH - , Cl - , NO3 - , SO4 2- , HSO4 - , PO4 3- , HPO4 2- , H2PO4 - , CO3 2- or HCO3 - or any one or a combination of at least two of them.

[0026] Preferably, the metal includes any one or a combination of at least two of iron powder, aluminum powder, nickel powder, or copper powder, and is preferably copper powder or nickel-iron alloy.

[0027] Preferably, the oxide includes any one or a combination of at least two of silicon dioxide, titanium dioxide, zirconium dioxide, aluminum oxide, zinc oxide, iron oxide, or copper oxide.

[0028] Preferably, the carbide includes silicon carbide.

[0029] Preferably, the types of the grinding aid material A and the grinding aid material B are the same.

[0030] Preferably, the average particle size of the grinding aid material A is 50 - 10000 nm, such as 50 nm, 52 nm, 55 nm, 60 nm, 80 nm, 100 nm, 300 nm, 500 nm, 700 nm, 900 nm, 1000 nm, 1200 nm, 1400 nm, 1500 nm, 1700 nm, 1800 nm, 2000 nm, 5000 nm, 6000 nm, 7000 nm, 8000 nm, or 9000 nm, etc., and is preferably 50 - 2000 nm.

[0031] Preferably, the average particle size of the grinding aid material B is 50 - 10000 nm, such as 50 nm, 52 nm, 55 nm, 60 nm, 80 nm, 100 nm, 300 nm, 500 nm, 700 nm, 900 nm, 1000 nm, 1200 nm, 1400 nm, 1500 nm, 1700 nm, 1800 nm, 2000 nm, 5000 nm, 6000 nm, 7000 nm, 8000 nm, or 9000 nm, etc., and is preferably 50 - 2000 nm.

[0032] Preferably, the ratio of the average particle size of the grinding aid material A to the average particle size of the grinding aid material B is (2 - 15):1, such as 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, or 15:1, etc.

[0033] In the present invention, if the ratio of the average particle size of the grinding aid material A to the average particle size of the grinding aid material B is lower than 2:1, there is not much difference between the added grinding aid material A and the grinding aid material B, and the ternary synergistic ball milling effect cannot be achieved; if the ratio of the average particle size of the grinding aid material A to the average particle size of the grinding aid material B is higher than 15:1, due to the too large particle size gap, the grinding aid material B will fill the gaps between the grinding aid material A, and the force cannot be transmitted therein, and the ball milling effect still cannot be achieved.

[0034] Preferably, the mass ratio of the grinding aid material A to the grinding aid material B is 1:(0.1 - 1), for example, it can be 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, or 1:1, etc.

[0035] Preferably, the mass ratio of the body material to the grinding aid material A is 1:(1 - 100), for example, it can be 1:3, 1:5, 1:7, 1:9, 1:10, 1:12, 1:15, 1:18, 1:20, 1:22, 1:24, 1:26, 1:28, 1:30, 1:35, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, or 1:95, etc., and preferably 1:(5 - 30).

[0036] In the present invention, when the mass ratio of the body material to the grinding aid material A is 1:(1 - 100), the auxiliary ball - milling effect of the grinding aid material can be fully exerted, while simplifying the process and saving costs. If the mass ratio of the body material to the grinding aid material is greater than 1:1, the amount of the grinding aid material is too small to play an auxiliary ball - milling role; if the mass ratio of the body material to the grinding aid material is less than 1:100, the amount of the grinding aid material is too large, resulting in unnecessary waste of resources, increasing the burden of post - impurity removal, and going against the original intention of high - efficiency energy conservation.

[0037] Preferably, the ball - milling balls include any one or a combination of at least two of agate balls, zirconia balls, alumina balls, polyurethane balls, steel balls, tungsten carbide balls, silicon nitride balls, or sintered corundum balls.

[0038] Preferably, the steel balls include stainless steel balls or quenched and tempered steel balls.

[0039] Preferably, the diameter of the ball - milling balls is 0.5 - 20 mm, for example, it can be 0.8 mm, 1 mm, 1.5 mm, 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, or 19 mm, etc.

[0040] Preferably, the mass ratio of the body material to the ball - milling balls is 1:(10 - 1000), for example, it can be 1:20, 1:30, 1:40, 1:45, 1:50, 1:55, 1:60, 1:70, 1:90, 1:100, 1:120, 1:150, 1:180, 1:200, 1:220, 1:250, 1:280, 1:300, 1:320, 1:350, 1:400, 1:500, 1:700, 1:900, or 1:950, etc., and preferably 1:(50 - 300).

[0041] Preferably, the ratio of the diameter of the ball milling balls to the average particle size of the grinding aid material A is (50 to 9000):1, for example, it can be 50:1, 100:1, 150:1, 200:1, 500:1, 1000:1, 1500:1, 2000:1, 3000:1, 4000:1, 5000:1, 6000:1, 7000:1, 8000:1, or 9000:1, etc.

[0042] In the present invention, if the ratio of the diameter of the ball milling balls to the average particle size of the grinding aid material A is less than 50:1, it will cause the grinding aid material A to be ground by the ball milling balls and fail to function; if the ratio of the diameter of the ball milling balls to the average particle size of the grinding aid material A is greater than 9000:1, it will cause the ball milling balls and the grinding aid material to be unable to effectively contact during the ball milling process, and the force cannot be effectively transmitted, still resulting in no effect.

[0043] Preferably, the time of the primary ball milling in step (1) is 0.5 to 120 h, for example, it can be 1 h, 3 h, 5 h, 8 h, 10 h, 12 h, 15 h, 18 h, 20 h, 22 h, 25 h, 28 h, 30 h, 32 h, 35 h, 38 h, 40 h, 42 h, 45 h, 48 h, 50 h, 60 h, 80 h, 100 h, 110 h, or 115 h, etc., and preferably 1 to 50 h.

[0044] Preferably, the time of the secondary ball milling in step (1) is 0.5 to 120 h, for example, it can be 1 h, 3 h, 5 h, 8 h, 10 h, 12 h, 15 h, 18 h, 20 h, 22 h, 25 h, 28 h, 30 h, 32 h, 35 h, 38 h, 40 h, 42 h, 45 h, 48 h, 50 h, 60 h, 80 h, 100 h, 110 h, or 115 h, etc., and preferably 1 to 50 h.

[0045] Preferably, step (1) further includes: after the secondary ball milling, a step of separating the ball milling balls.

[0046] Optionally, the ball milling balls are separated by a screening step.

[0047] Preferably, step (1) further includes: after the step of separating the ball milling balls, a step of separating the grinding aid material A and the grinding aid material B.

[0048] It should be noted that when the grinding aid material A and the grinding aid material B are ionic compounds, metals, or metal compounds, after separating the ball milling balls, a step of separating the grinding aid material A and / or the grinding aid material B can be carried out to obtain the ball milling product.

[0049] Preferably, the method for separating the grinding aid material A and the grinding aid material B includes water washing and / or acid washing.

[0050] Exemplarily, when the grinding aids A and B are water-soluble substances, taking advantage of their property of being soluble in water, a water-washing method is adopted for separation; when the grinding aids A and B are acid-soluble substances, taking advantage of their property of being soluble in acid, an acid-washing method is adopted for separation.

[0051] Preferably, the solvent in step (2) includes any one or a combination of at least two of N-methylpyrrolidone, N-vinylpyrrolidone, N-cyclohexylpyrrolidone, N-octylpyrrolidone, N-dodecylpyrrolidone, γ-butyrolactone, formamide, N-methylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, benzene, chlorobenzene, bromobenzene, benzonitrile, benzaldehyde, benzyl benzoate, dibenzyl ether, tetrahydrofuran, acetone, butanone, methanol, ethanol, isopropanol, n-hexane or water.

[0052] Preferably, in the mixed solution obtained by mixing in step (2), the concentration of the ball-milled product is 1 to 100 mg / mL, and for example, it can be 2 mg / mL, 5 mg / mL, 8 mg / mL, 10 mg / mL, 13 mg / mL, 15 mg / mL, 18 mg / mL, 20 mg / mL, 22 mg / mL, 25 mg / mL, 28 mg / mL, 30 mg / mL, 32 mg / mL, 35 mg / mL, 38 mg / mL, 40 mg / mL, 42 mg / mL, 45 mg / mL, 47 mg / mL, 49 mg / mL, 50 mg / mL, 60 mg / mL, 70 mg / mL, 80 mg / mL, 90 mg / mL or 100 mg / mL, etc.

[0053] In the present invention, when the concentration of the ball-milled product is 1 to 100 mg / mL, ultrasound can effectively pulverize the ball-milled product. If the concentration is less than 1 mg / mL, the concentration of the mixed solution is relatively low, and the effect of ultrasound on the material is not obvious, affecting the final yield; if the concentration is greater than 100 mg / mL, the mixed solution reaches a supersaturated state, resulting in waste of materials.

[0054] The power of the ultrasound in step (2) is 50 to 1000 W, and for example, it can be 60 W, 80 W, 100 W, 150 W, 200 W, 250 W, 300 W, 350 W, 400 W, 450 W, 500 W, 550 W, 600 W, 650 W, 700 W, 750 W, 800 W, 850 W, 900 W or 950 W, etc., and preferably 100 to 500 W.

[0055] In the present invention, if the power of the ultrasound is less than 50 W, the ultrasound effect is not obvious; if the power of the ultrasound is greater than 1000 W, it has little impact on the yield of the final sub-nano material, and it will cause waste of resources, going against the original intention of high efficiency and energy conservation.

[0056] Preferably, the time of the ultrasonic wave in step (2) is 0.5 to 120 h, such as 0.8 h, 1 h, 3 h, 5 h, 8 h, 10 h, 12 h, 15 h, 18 h, 20 h, 22 h, 25 h, 28 h, 30 h, 32 h, 35 h, 38 h, 40 h, 42 h, 45 h, 48 h, 50 h, 60 h, 80 h, 100 h, 110 h or 115 h, etc., and preferably 1 to 50 h.

[0057] In the present invention, by regulating two parameters of ultrasonic power and ultrasonic time, the yield of sub-nano materials can be controlled.

[0058] Preferably, the ultrasonic wave in step (2) includes probe-type ultrasonic wave or water-bath type ultrasonic wave.

[0059] Preferably, step (2) further includes: after the ultrasonic wave, a sieving step is carried out.

[0060] In the present invention, after ultrasonic wave, a dispersion liquid of materials with full coverage of sizes (from nano level to sub-nano level) can be obtained, and sub-nano materials can be obtained by size sieving.

[0061] Preferably, the sieving method includes any one or a combination of at least two of cascade centrifugation, filtration or chromatography.

[0062] It should be noted that when the grinding aid material A and the grinding aid material B are oxides or carbides, sieving can be carried out multiple times. First, the grinding aid material A and the grinding aid material B are separated; then, sub-nano materials are sieved out.

[0063] Preferably, the rotation speed of the cascade centrifugation is 500 to 20000 r / min, such as 500 r / min, 600 r / min, 700 r / min, 900 r / min, 1000 r / min, 1500 r / min, 2000 r / min, 2500 r / min, 3000 r / min, 3500 r / min, 4000 r / min, 4500 r / min, 5000 r / min, 5500 r / min, 6000 r / min, 6500 r / min, 7000 r / min, 7500 r / min, 8000 r / min, 9000 r / min, 10000 r / min, 11000 r / min, 12000 r / min, 13000 r / min, 14000 r / min, 15000 r / min, 16000 r / min, 17000 r / min, 18000 r / min, 19000 r / min or 20000 r / min, etc., and preferably 1000 to 16000 r / min.

[0064] Preferably, during the cascade centrifugation process, the rotational speed gradient increases, and the rotational speed difference between adjacent stages is 50 - 5000 r / min. For example, it can be 50 r / min, 60 r / min, 70 r / min, 90 r / min, 100 r / min, 150 r / min, 200 r / min, 250 r / min, 300 r / min, 400 r / min, 500 r / min, 700 r / min, 1000 r / min, 1200 r / min, 1300 r / min, 1500 r / min, 2000 r / min, 2500 r / min, 3000 r / min, 3500 r / min, 4000 r / min, 4500 r / min or 5000 r / min, etc., and preferably 1000 - 4000 r / min.

[0065] Preferably, during the cascade centrifugation process, the centrifugation time for each stage is independently 1 - 120 min. For example, it can be 1 min, 2 min, 5 min, 7 min, 10 min, 15 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min, etc., and preferably 5 - 60 min.

[0066] Preferably, the number of cascade centrifugation times is at least once. For example, it can be once, twice, three times, five times, seven times, ten times, fifteen times or twenty times, etc.

[0067] In the present invention, when the grinding aid material A and the grinding aid material B are oxides or carbides, at least two cascade centrifugations can be performed. First, the grinding aid material A and the grinding aid material B are separated, and then the sub-nano material is sieved.

[0068] In the present invention, what is obtained after cascade centrifugation is a dispersion liquid containing the sub-nano material.

[0069] Exemplarily, a method for preparing a sub-nano material powder is provided, including: mixing the dispersion liquid containing the sub-nano material with a poor solvent, performing solid-liquid separation, and drying the solid phase obtained from the solid-liquid separation to obtain the sub-nano material powder. Among them, the poor solvent can be any one of n-hexane, cyclohexane or petroleum ether.

[0070] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0071] (Ⅰ) Ball-milling the matrix material, ball-milling balls and the grinding aid material A for 0.5 - 120 h to obtain a ball-milled product; then ball-milling the ball-milled product and the grinding aid material B for 0.5 - 120 h, and after separating the ball-milling balls, a ball-milled product is obtained;

[0072] (II) Mix the ball-milled product with a solvent to obtain a mixed solution with a concentration of the ball-milled product of 1 to 100 mg / mL. After ultrasonicating the mixed solution at a power of 50 to 1000 W for 0.5 to 120 h, the sub-nanometer material is obtained through screening;

[0073] Wherein, the ratio of the average particle size of the grinding aid material A to the average particle size of the grinding aid material B is (2 to 15):1.

[0074] In a second aspect, the present invention provides a sub-nanometer material, which is prepared by the preparation method described in the first aspect. The particle size of the sub-nanometer material is less than 1 nm, for example, it can be 0.99 nm, 0.9 nm, 0.85 nm, 0.8 nm, 0.75 nm, 0.7 nm, 0.65 nm, 0.6 nm, 0.55 nm, 0.5 nm, 0.45 nm, 0.4 nm, 0.35 nm, 0.3 nm, 0.25 nm, 0.2 nm, 0.15 nm or 0.1 nm, etc.

[0075] Preferably, the particle size of the sub-nanometer material is greater than or equal to 0.1 nm.

[0076] The numerical ranges described in the present invention not only include the point values exemplified above, but also include any point values between the above numerical ranges not exemplified. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range.

[0077] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0078] (1) The present invention provides a preparation method for a sub-nanometer material. This method is a top-down preparation strategy. Through the synergistic effect of two physical methods, ball milling and ultrasonication, the bulk material is effectively broken, and finally a sub-nanometer material with uniform particle size is obtained; during the ball milling process, the ball milling balls and the grinding aid material A can form a binary synergistic ball milling effect. In particular, the introduction of the grinding aid material A greatly increases the stress points acting on the bulk material (including transverse stress and normal stress), and generates a huge pressure under a very small contact area, thereby crushing the large material into the nanometer scale; then, the grinding aid material B with a smaller particle size is introduced, which can make the ball milling balls, the grinding aid material A and the grinding aid material C form a ternary synergistic ball milling effect, and further crush the nanometer-scale material into the sub-nanometer level;

[0079] This method has the advantages of high efficiency, environmental protection, simple operation and low cost, etc., is suitable for large-scale production, and has good application prospects; at the same time, the sub-nanometer material prepared by this method has high purity, good dispersibility, a yield of up to 18%, uniform particle size, and controllable size;

[0080] (2) The present invention provides a sub-nanometer material, and the particle size of the sub-nanometer material is less than 1 nm. Description of the Drawings

[0081] Figure 1 It is a scanning electron microscope image of the WS2 bulk material provided in Example 2 of the present invention.

[0082] Figure 2 It is a transmission electron microscope image of the WS2 sub-nanometer material provided in Example 2 of the present invention.

[0083] Figure 3 It is an optical picture of the WS2 sub-nanometer material dispersion provided in Example 2 of the present invention. Detailed Description of the Invention

[0084] The technical solution of the present invention will be further described below through specific embodiments.

[0085] Example 1

[0086] This example provides a preparation method of a MoS2 sub-nanometer material, and the preparation method includes the following steps:

[0087] (1) Mix 0.5 g of MoS2 bulk material with an average particle size of 10 μm, 5 g of silica spheres (denoted as grinding aid material A, with an average particle size of 500 nm), and 50 g of agate balls (with a diameter of 3 mm), and perform primary ball milling for 12 h at a rotation speed of 500 rpm; then add 2 g of finer silica spheres (denoted as grinding aid material B, with an average particle size of 200 nm), and perform secondary ball milling for 12 h at a rotation speed of 500 rpm, and separate the agate balls by screening to obtain the coarsened product after ball milling;

[0088] (2) Mix the coarsened product obtained in step (1) with N-methylpyrrolidone (NMP) to obtain a mixed solution with a coarsened product concentration of 50 mg / mL, and ultrasonicate the mixed solution at a power of 200 W for 9 h;

[0089] (3) Perform two-stage cascade centrifugation on the mixed solution obtained in step (2). First, centrifuge at rotation speeds of 4000 rpm, 8000 rpm, 12000 rpm, and 16000 rpm in sequence for 30 min; then collect 2 / 3 of the supernatant, add appropriate amounts of good solvent and poor solvent (where the volume ratio of NMP: n-hexane: isopropanol is 5:4:1), and perform the second-stage cascade centrifugation. Centrifuge at rotation speeds of 4000 rpm, 8000 rpm, 12000 rpm, and 16000 rpm in sequence for 30 min, and collect 2 / 3 of the supernatant to obtain a dispersion containing the MoS2 sub-nanometer material.

[0090] Example 2

[0091] This embodiment provides a method for preparing WS2 sub-nanomaterials, and the preparation method includes the following steps:

[0092] (1) Mix 1 g of WS2 bulk material, 10 g of silica spheres (denoted as grinding aid material A, with an average particle size of 500 nm), and 100 g of agate balls (with a diameter of 3 mm), and ball mill once for 12 h at a rotation speed of 800 rpm; then add 5 g of finer silica spheres (denoted as grinding aid material B, with an average particle size of 200 nm), and ball mill twice for 12 h at a rotation speed of 800 rpm. Separate the agate balls by sieving to obtain the coarsened product after ball milling. Among them, the surface morphology of the WS2 bulk material used is as Figure 1 shown. It can be seen from the figure that the average particle size of the WS2 bulk material reaches more than 2 μm, and the size is relatively large;

[0093] (2) Mix the coarsened product obtained in step (1) with N-methylpyrrolidone (NMP) to obtain a mixed solution with a coarsened product concentration of 50 mg / mL, and ultrasonically treat the mixed solution at a power of 200 W for 9 h;

[0094] (3) Perform two-stage cascade centrifugation on the mixed solution obtained in step (2). First, centrifuge at rotation speeds of 4000 rpm, 8000 rpm, 12000 rpm, and 16000 rpm in sequence for 30 min; then collect 2 / 3 of the supernatant, add appropriate amounts of good solvent and poor solvent (where the volume ratio of NMP: n-hexane: isopropanol is 5:4:1), and perform the second-stage cascade centrifugation. Centrifuge at rotation speeds of 4000 rpm, 8000 rpm, 12000 rpm, and 16000 rpm in sequence for 30 min, and collect 2 / 3 of the supernatant to obtain a dispersion containing the WS2 sub-nanomaterials. Its optical picture is as Figure 3 shown. It can be seen from the figure that the dispersion of the WS2 sub-nanomaterials (in N-methylpyrrolidone) is brown, evenly dispersed, without precipitation and stratification phenomena, proving that the sub-nanomaterials obtained by the preparation method of the present invention have good dispersibility.

[0095] Example 3

[0096] This embodiment provides a method for preparing graphene sub-nanomaterials, and the preparation method includes the following steps:

[0097] (1) Mix 0.5 g of graphite sheet bulk material with an average particle size of 100 μm, 5 g of copper powder (denoted as grinding aid material A, with an average particle size of 500 nm), and 50 g of agate balls (with a diameter of 3 mm), and ball mill once for 12 h at a rotation speed of 1000 rpm; then add 2 g of finer copper powder (denoted as grinding aid material B, with an average particle size of 200 nm), and ball mill twice for 12 h at a rotation speed of 1000 rpm. Separate the agate balls by sieving to obtain the coarsened product after ball milling;

[0098] (2) Mix the crude product obtained in step (1) with N-methylpyrrolidone (NMP) to obtain a mixed solution with a crude product concentration of 50 mg / mL, and ultrasonicate the mixed solution at a power of 200 W for 9 h;

[0099] (3) Perform two-stage cascaded centrifugation on the mixed solution obtained in step (2). First, centrifuge at 4000 rpm, 8000 rpm, 12000 rpm, and 16000 rpm for 30 min in sequence; then collect 2 / 3 of the supernatant, add an appropriate amount of good solvent and poor solvent (where the volume ratio of NMP: n-hexane: isopropanol is 5:4:1), perform the second-stage cascaded centrifugation, centrifuge at 4000 rpm, 8000 rpm, 12000 rpm, and 16000 rpm for 30 min in sequence, collect 2 / 3 of the supernatant, and obtain a dispersion containing the graphene sub-nanomaterial.

[0100] Example 4

[0101] This example provides a method for preparing copper sub-nanomaterials, and the preparation method includes the following steps:

[0102] (1) Mix 1 g of copper bulk material with an average particle size of 10 μm, 10 g of silica spheres (denoted as grinding aid material A, with an average particle size of 500 nm), and 100 g of agate balls (with a diameter of 3 mm), and perform primary ball milling at a rotation speed of 800 rpm for 12 h; then add 5 g of finer silica spheres (denoted as grinding aid material B, with an average particle size of 200 nm), and perform secondary ball milling at a rotation speed of 800 rpm for 12 h, and separate the agate balls by screening to obtain the ball-milled crude product;

[0103] (2) Mix the crude product obtained in step (1) with N-methylpyrrolidone (NMP) to obtain a mixed solution with a crude product concentration of 50 mg / mL, and ultrasonicate the mixed solution at a power of 200 W for 9 h;

[0104] (3) Perform two-stage cascaded centrifugation on the mixed solution obtained in step (2). First, centrifuge at 4000 rpm, 8000 rpm, 12000 rpm, and 16000 rpm for 30 min in sequence; then collect 2 / 3 of the supernatant, add an appropriate amount of good solvent and poor solvent (where the volume ratio of NMP: n-hexane: isopropanol is 5:4:1), perform the second-stage cascaded centrifugation, centrifuge at 4000 rpm, 8000 rpm, 12000 rpm, and 16000 rpm for 30 min in sequence, collect 2 / 3 of the supernatant, and obtain a dispersion containing the copper sub-nanomaterial.

[0105] Example 5

[0106] The difference between this example and Example 1 is only that the time for primary ball milling and secondary ball milling in step (1) is adjusted to 18 h, and the ultrasonic time in step (2) is adjusted to 6 h, and the rest is exactly the same as Example 1.

[0107] Example 6

[0108] The difference between this example and Example 1 is only that in step (2), the concentration of the crude product in the mixed solution is adjusted to 100 mg / mL, and the rest is exactly the same as Example 1.

[0109] Example 7

[0110] The difference between this example and Example 1 is only that in step (1), the grinding aid material B is replaced with silica spheres with an average particle size of 50 nm, and the rest is exactly the same as Example 1.

[0111] Example 8

[0112] The difference between this example and Example 1 is only that in step (1), the grinding aid material B is replaced with silica spheres with an average particle size of 100 nm, and the rest is exactly the same as Example 1.

[0113] Example 9

[0114] The difference between this example and Example 1 is only that in step (2), the ultrasonic power is adjusted to 40 W, and the rest is exactly the same as Example 1.

[0115] Example 10

[0116] The difference between this example and Example 1 is only that in step (2), the ultrasonic power is adjusted to 1100 W, and the rest is exactly the same as Example 1.

[0117] Example 11

[0118] The difference between this example and Example 1 is only that in step (2), the concentration of the crude product in the mixed solution is adjusted to 5 mg / mL, and the rest is exactly the same as Example 1.

[0119] Example 12

[0120] The difference between this example and Example 1 is only that in step (2), the concentration of the crude product in the mixed solution is adjusted to 200 mg / mL, and the rest is exactly the same as Example 1.

[0121] Example 13

[0122] This example provides a method for preparing PbS sub-nanomaterials, and the preparation method includes the following steps:

[0123] (1) Mix 2 g of PbS bulk material with an average particle size of 100 μm, 20 g of calcium hydroxide pellets (denoted as grinding aid material A, with an average particle size of 1000 nm), and 100 g of zirconia balls (with a diameter of 5 mm), and ball mill them once for 12 h at a rotation speed of 500 rpm; then add 10 g of finer calcium hydroxide pellets (denoted as grinding aid material B, with an average particle size of 100 nm), and ball mill them twice for 12 h at a rotation speed of 500 rpm. Separate the zirconia balls by sieving to obtain the coarsely ground product;

[0124] (2) Pickle the coarsely ground product obtained in step (1). The solvent used is dilute hydrochloric acid with a mass fraction of 10%. Mix the pickled coarsely ground product with a good solvent and a poor solvent (where the volume ratio of NMP: n - hexane: isopropanol is 5:4:1) to obtain a mixed solution with a concentration of the coarsely ground product of 50 mg / mL. Ultrasonic the mixed solution at a power of 300 W for 10 h;

[0125] (3) Perform primary cascade centrifugation on the mixed solution obtained in step (2). Centrifuge it successively at rotation speeds of 5000 rpm, 8000 rpm, 11000 rpm, and 14000 rpm for 30 min each, and collect 2 / 3 of the supernatant to obtain a dispersion containing the PbS sub - nanometer material.

[0126] Example 14

[0127] This example provides a method for preparing polyacrylonitrile sub - nanometer materials. The preparation method includes the following steps:

[0128] (1) Mix 5 g of polyacrylonitrile bulk material with an average particle size of 1 mm, 100 g of silicon carbide pellets (denoted as grinding aid material A, with an average particle size of 2000 nm), and 1000 g of silicon nitride balls (with a diameter of 10 mm), and ball mill them once for 12 h at a rotation speed of 800 rpm; then add 100 g of finer silicon carbide pellets (denoted as grinding aid material B, with an average particle size of 150 nm), and ball mill them twice for 12 h at a rotation speed of 800 rpm. Separate the silicon nitride balls by sieving to obtain the coarsely ground product;

[0129] (2) Mix the coarsely ground product obtained in step (1) with N - methylpyrrolidone (NMP) to obtain a mixed solution with a concentration of the coarsely ground product of 50 mg / mL. Ultrasonic the mixed solution at a power of 500 W for 9 h;

[0130] (3) Centrifuge the mixture obtained in step (2) twice in series. First, centrifuge at speeds of 3000 rpm, 5000 rpm, 7000 rpm, and 9000 rpm for 30 minutes in sequence; then collect 2 / 3 of the supernatant, add an appropriate amount of good solvent and poor solvent (where the volume ratio of NMP: n-hexane: isopropanol is 5:4:1), and perform the second series of centrifugation. Centrifuge at speeds of 3000 rpm, 5000 rpm, 7000 rpm, and 9000 rpm for 30 minutes in sequence, and collect 2 / 3 of the supernatant to obtain a dispersion containing the polyacrylonitrile sub-nanometer material.

[0131] Example 15

[0132] The difference between this example and Example 1 is only that in step (1), the ratio of the average particle size of grinding aid material A to the average particle size of grinding aid material B is adjusted to 1.5, and the rest is exactly the same as Example 1.

[0133] Example 16

[0134] The difference between this example and Example 1 is only that in step (1), the ratio of the average particle size of grinding aid material A to the average particle size of grinding aid material B is adjusted to 17, and the rest is exactly the same as Example 1.

[0135] Example 17

[0136] The difference between this example and Example 1 is only that in step (1), the ratio of the diameter of the grinding balls to the average particle size of grinding aid material A is adjusted to 10:1, and the rest is exactly the same as Example 1.

[0137] Example 18

[0138] The difference between this example and Example 1 is only that in step (1), the ratio of the diameter of the grinding balls to the average particle size of grinding aid material A is adjusted to 10000:1, and the rest is exactly the same as Example 1.

[0139] Comparative Example 1

[0140] The difference between this comparative example and Example 1 is only that in this comparative example, without going through the ball milling in step (1), directly mix the MoS2 bulk material with NMP for step (2), and the rest is exactly the same as Example 1.

[0141] Comparative Example 2

[0142] The difference between this comparative example and Example 1 is only that in step (1), do not use grinding aid material A and grinding aid material B, directly mix the MoS2 bulk material with agate balls for ball milling, and the rest is exactly the same as Example 1.

[0143] Comparative Example 3

[0144] The difference between this comparative example and Example 1 is only that in step (1), grinding aid material B is not used, and the rest is exactly the same as in Example 1.

[0145] Comparative Example 4

[0146] The difference between this comparative example and Example 1 is only that the ultrasonic step in step (2) is omitted, and the rest is exactly the same as in Example 1.

[0147] Comparative Example 5

[0148] The difference between this comparative example and Example 1 is only that grinding aid material B is added first for nodularizing once, and then grinding aid material A is added for secondary ball milling, and the rest is exactly the same as in Example 1.

[0149] Performance Test

[0150] (1) Yield Test:

[0151] The dispersion liquid containing sub-nano materials provided in Examples 1 - 18 and Comparative Examples 1 - 5 was mixed with a poor solvent for precipitation. After solid-liquid separation, the obtained solid phase was dried to obtain sub-nano material powder. Among them, the poor solvent used was n-hexane, and the volume ratio of the poor solvent to the dispersion liquid was 2:1.

[0152] The sub-nano material powder was weighed, and then compared with the mass of the input bulk material to calculate the yield. Yield = mass of sub-nano material powder / mass of bulk material.

[0153] (2) Particle Size Distribution Test:

[0154] The dispersion liquids containing sub-nano materials provided in Examples 1 - 18 and Comparative Examples 1 - 5 were tested by scanning transmission electron microscopy (STEM). The specific method was as follows: The sub-nano material powder was prepared into an ethanol dispersion liquid with a concentration of 0.01 mg / mL, and simple ultrasonic treatment was sufficient; then the ethanol dispersion liquid was dropped on a copper grid. After the solvent ethanol completely volatilized, the surface morphology was characterized by STEM, and the particle size distribution range was statistically obtained based on the transmission electron microscopy images.

[0155] Among them, the transmission electron microscopy image of the WS2 sub-nano material provided in Example 2 is as Figure 2 shown. It can be seen from the figure that the particle size distribution of the WS2 sub-nano material is uniform, and the average particle size is about 0.5 nm.

[0156] The test results are shown in Table 1.

[0157] Table 1

[0158]

[0159]

[0160] Analysis:

[0161] From the results of Examples 1-8, Example 11, and Examples 13-14, it can be seen that the preparation method provided by the present invention can prepare sub-nanomaterials with a particle size less than 1 nm. Under the optimal conditions, the single-pass yield can reach 18%.

[0162] From the results of Example 1 and Examples 9-10, it can be seen that if the power of ultrasonic is too low, the ultrasonic effect is not obvious, and it is impossible to effectively prepare sub-nanomaterials with a size less than 1 nm; if the power of ultrasonic is too high, it has little effect on the yield of the final sub-nanomaterials, but it will cause waste of resources, which violates the original intention of high efficiency and energy saving.

[0163] From the results of Example 1 and Example 12, it can be seen that if the concentration of the mixed solution in step (2) is too high, the mixed solution reaches a supersaturated state, and there is no surplus space for the sub-nanomaterials. The materials will stack together and be difficult to separate, resulting in waste of materials.

[0164] From the results of Example 1 and Examples 15-16, it can be seen that if the ratio of the average particle size of the grinding aid material A to the average particle size of the grinding aid material B is too low, the ternary synergistic ball milling effect cannot be exerted, and sub-nanomaterials cannot be effectively prepared, but only stay in the quantum scale (between 1-10 nm); if the ratio of the average particle size of the grinding aid material A to the average particle size of the grinding aid material B is too high, sub-nanomaterials cannot be obtained either. The grinding aid material B will fill the gaps in A and cannot function.

[0165] From the results of Example 1 and Examples 17-18, it can be seen that if the ratio of the diameter of the ball milling ball to the average particle size of the grinding aid material A is too small, the grinding aid material A will be ground by the ball milling ball and cannot function; if the ratio of the diameter of the ball milling ball to the average particle size of the grinding aid material A is too large, the ball milling ball and the grinding aid material cannot effectively contact during the ball milling process, and the force cannot be effectively transmitted, still resulting in no effect.

[0166] From the results of Example 1 and Comparative Examples 1-5, it can be seen that sub-nanomaterials cannot be prepared by ultrasonic alone or ball milling alone. Moreover, the addition and addition sequence of the two kinds of grinding aid materials with different particle sizes are crucial. If appropriate grinding aid materials are not added during ball milling, effective fragmentation of the bulk material cannot be achieved, and thus sub-nanomaterials cannot be obtained.

[0167] The applicant declares that the above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for preparing a sub-nanometer material, characterized in that, The preparation method includes the following steps: (1) After primary ball milling of the matrix material, ball milling balls and grinding aid material A, grinding aid material B is added to the ball milling system for secondary ball milling to obtain a ball milled product; (2) The ball milled product is mixed with a solvent and ultrasonicated to obtain the sub-nano material; Wherein, the average particle size of the grinding aid material A is larger than that of the grinding aid material B; The average particle size ratio of the grinding aid material A to the grinding aid material B is (2 - 15):1; The ratio of the diameter of the ball milling balls to the average particle size of the grinding aid material A is (100 - 9000):1; The particle size of the sub-nano material is less than 1 nm.

2. The preparation method according to claim 1, wherein, The matrix material includes a layered material and / or a non-layered material.

3. The preparation method according to claim 2, wherein The layered material includes any one or a combination of at least two of graphite, boron nitride, black phosphorus, g-C3N4, MoS2, MoSe2, MoTe2, WS2, WSe2, WTe2, TiS2, MnS2, FeS2, CoS2, NiS2, In2S3, In2Se3, In2Te3, Bi2Se3, Bi2Te3, Sb2Te3, Ti2C, Ti3C2, Ti4N3, V2C, Nb2C, Mo2C or Mo2TiC2.

4. The preparation method according to claim 2, characterized in that, The non-layered material includes any one or a combination of at least two of a metal material, an inorganic semiconductor material or an organic semiconductor material.

5. The preparation method according to claim 4, characterized in that, The metal elements in the metal material include any one or a combination of at least two of Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Ag, Cd, W, Pb, Pt, Au, Ge, Sn, Sb or Bi elements.

6. The preparation method according to claim 4, characterized in that, The inorganic semiconductor material includes any one or a combination of at least two of IIIA-VA group compounds, IIIA-VIA group compounds, IVA-IVA group compounds, IVA-VA group compounds, IVA-VIA group compounds, VA-VIA group compounds, oxides of transition elements, Si-AlP, Ge-GaAs, InAs-InSb, AlSb-GaSb, InAs-InP, GaAs-GaP, ZnSiP2, ZnGeP2, ZnGeAs2, CdGeAs2, CdSnSe2, CuGaSe2, AgInTe2, AgTlTe2, CuInSe2, CuAlS2, Cu3AsSe4, Ag3AsTe4, Cu3SbS4, Ag3SbSe4 or Cu2FeSnS4.

7. The preparation method according to claim 6, characterized in that, The inorganic semiconductor material is any one or a combination of at least two of PbS, CdS, CuS, FeS, ZnS, PbSe, CdSe, CuSe, FeSe, ZnSe, PbTe, CdTe, CuTe, FeTe, ZnTe, GaN, InP, ZnO, TiO2, CdO, SiO2, Si3N4, SiC, GaAs, Cu3SbS4 or Ag3SbSe4.

8. The preparation method according to claim 4, characterized in that, The organic semiconductor material includes any one or a combination of at least two of naphthalene, anthracene, polyacrylonitrile or phthalocyanine.

9. The preparation method according to claim 1, characterized in that, The average particle size of the matrix material is 0.1 - 10000 μm.

10. The preparation method according to claim 9, characterized in that, The average particle size of the matrix material is 0.5 - 1000 μm.

11. The preparation method according to claim 1, characterized in that, The grinding aid material A and the grinding aid material B independently include any one or a combination of at least two of ionic compounds, metals, oxides or carbides.

12. The preparation method according to claim 11, characterized in that, The grinding aid material A and the grinding aid material B are independently oxides and / or carbides.

13. The preparation method according to claim 11, wherein, The cations of the ionic compound include cations of Group IA elements, cations of Group IIA elements, or NH4 + Any one or a combination of at least two of them.

14. The preparation method according to claim 11, wherein The anion of the ionic compound includes OH - , Cl - , NO3 - , SO4 2- , HSO4 - , PO4 3- , HPO4 2- , H2PO4 - , CO3 2- or HCO3 - and is any one or a combination of at least two of them.

15. The preparation method according to claim 11, characterized in that, The metal includes any one or a combination of at least two of iron powder, aluminum powder, nickel powder or copper powder.

16. The preparation method according to claim 15, characterized in that, The metal is copper powder or nickel - iron alloy.

17. The preparation method according to claim 11, characterized in that, The oxide includes any one or a combination of at least two of silicon dioxide, titanium dioxide, zirconium dioxide, aluminum oxide, zinc oxide, iron oxide or copper oxide.

18. The preparation method according to claim 11, characterized in that, The carbide includes silicon carbide.

19. The preparation method according to claim 11, characterized in that, The types of the grinding aid material A and the grinding aid material B are the same.

20. The preparation method according to claim 1, characterized in that, The average particle size of the grinding aid material A is 50 - 10000 nm.

21. The preparation method according to claim 20, characterized in that, The average particle size of the grinding aid material A is 50 - 2000 nm.

22. The preparation method according to claim 1, characterized in that, The average particle size of the grinding aid material B is 50 - 10000 nm.

23. The preparation method according to claim 22, characterized in that, The average particle size of the grinding aid material B is 50 - 2000 nm.

24. The preparation method according to claim 1, wherein, The mass ratio of the grinding aid material A to the grinding aid material B is 1:(0.1 - 1).

25. The preparation method according to claim 1, characterized in that, The mass ratio of the matrix material to the grinding aid material A is 1:(1 - 100).

26. The preparation method according to claim 25, characterized in that, The mass ratio of the matrix material to the grinding aid material A is 1:(5 - 30).

27. The preparation method according to claim 1, characterized in that, The grinding balls include any one or a combination of at least two of agate balls, zirconia balls, alumina balls, polyurethane balls, steel balls, tungsten carbide balls, silicon nitride balls or sintered corundum balls.

28. The preparation method according to claim 1, characterized in that, The diameter of the grinding balls is 0.5 - 20 mm.

29. The preparation method according to claim 1, characterized in that, The mass ratio of the matrix material to the grinding balls is 1:(10 - 1000).

30. The preparation method according to claim 29, characterized in that, The mass ratio of the matrix material to the grinding balls is 1:(50 - 300).

31. The preparation method according to claim 1, characterized in that, The time of the first ball - milling in step (1) is 0.5 - 120 h.

32. The preparation method according to claim 31, characterized in that, The time of the first ball - milling in step (1) is 1 - 50 h.

33. The preparation method according to claim 1, characterized in that, The time of the second ball - milling in step (1) is 0.5 - 120 h.

34. The preparation method according to claim 33, characterized in that, The time of the second ball - milling in step (1) is 1 - 50 h.

35. The preparation method according to claim 1, characterized in that, Step (1) further includes: after the second ball - milling, a step of separating the grinding balls.

36. The preparation method according to claim 35, characterized in that, After the step of separating the grinding balls, a step of separating the grinding aid material A and the grinding aid material B is carried out.

37. The preparation method according to claim 36, wherein The method for separating the grinding aid material A and the grinding aid material B includes water washing and / or acid washing.

38. The preparation method according to claim 1, characterized in that, The solvent in step (2) includes any one or a combination of at least two of N - methylpyrrolidone, N - vinylpyrrolidone, N - cyclohexylpyrrolidone, N - octylpyrrolidone, N - dodecylpyrrolidone, γ - butyrolactone, formamide, N - methylformamide, N,N - dimethylformamide, N,N - dimethylacetamide, dimethyl sulfoxide, benzene, chlorobenzene, bromobenzene, benzonitrile, benzaldehyde, benzyl benzoate, dibenzyl ether, tetrahydrofuran, acetone, butanone, methanol, ethanol, isopropanol, n - hexane or water.

39. The preparation method according to claim 1, characterized in that, In the mixed solution obtained by mixing in step (2), the concentration of the ball-milled product is 1 to 100 mg / mL.

40. The preparation method according to claim 1, characterized in that, The power of the ultrasonic wave in step (2) is 50 to 1000 W.

41. The preparation method according to claim 40, characterized in that The power of the ultrasonic wave in step (2) is 100 to 500 W.

42. The preparation method according to claim 1, characterized in that, The time of the ultrasonic wave in step (2) is 0.5 to 120 h.

43. The preparation method according to claim 42, wherein The time of the ultrasonic wave in step (2) is 1 to 50 h.

44. The preparation method according to claim 1, characterized in that, Step (2) further includes: after the ultrasonic wave, a sieving step.

45. The preparation method according to claim 44, characterized in that, The sieving method includes any one or a combination of at least two of cascade centrifugation, filtration, or chromatography.

46. The preparation method according to claim 45, wherein, The rotation speed of the cascade centrifugation is 500 to 20000 r / min.

47. The preparation method according to claim 46, wherein, The rotation speed of the cascade centrifugation is 1000 to 16000 r / min.

48. The preparation method according to claim 45, characterized in that, During the cascade centrifugation process, the rotation speed gradient increases, and the rotation speed difference between adjacent levels is 50 to 5000 r / min.

49. The preparation method according to claim 48, wherein, During the cascade centrifugation process, the rotation speed gradient increases, and the rotation speed difference between adjacent levels is 1000 to 4000 r / min.

50. The preparation method according to claim 45, characterized in that, During the cascade centrifugation process, the centrifugation time for each level is independently 1 to 120 min.

51. The preparation method according to claim 50, characterized in that, During the cascade centrifugation process, the centrifugation time for each level is independently 5 to 60 min.

52. The preparation method according to claim 45, characterized in that, The number of times of the cascade centrifugation is at least once.

53. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: (Ⅰ) Ball-mill the bulk material, ball-milling balls, and grinding aid material A for 0.5 to 120 h to obtain a ball-milled product; then ball-mill the ball-milled product and grinding aid material B for 0.5 to 120 h, and after separating the ball-milling balls, obtain a ball-milled product; (Ⅱ) Mix the ball-milled product with a solvent to obtain a mixed solution with a concentration of the ball-milled product of 1 to 100 mg / mL, ultrasonically treat the mixed solution at a power of 50 to 1000 W for 0.5 to 120 h, and then obtain the sub-nano material through sieving; Wherein, the ratio of the average particle size of the grinding aid material A to the average particle size of the grinding aid material B is (2 to 15):

1.

54. A sub-nano material, characterized in that, The sub-nano material is prepared by the preparation method according to any one of claims 1-53, and the particle size of the sub-nano material is less than 1 nm.

55. The sub-nano material according to claim 54, wherein The particle size of the sub-nano material is greater than or equal to 0.1 nm.

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