Method for metal-atom catalyzed growth of two-dimensional nanomaterials

Abstract

The application provides a metal atom catalytic growth method of two-dimensional nanomaterials, and the preparation method comprises the following steps: (1) transferring the two-dimensional nanomaterial to be grown to a micro-grid; (2) doping the metal atom into the two-dimensional nanomaterial by using a heat treatment method; and (3) growing the two-dimensional nanomaterial after doping by using electron beam irradiation. The growth method can realize the control of the two-dimensional nanomaterial at an atomic scale and realize precise processing.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation, and relates to a catalytic preparation method for nanomaterials, particularly a metal atom catalytic growth method for two-dimensional nanomaterials. Background Technology

[0002] Catalysts play an indispensable role in driving global economic development through industrial applications. Over 90% of chemical reactions require catalysts, and the continuous development of more effective, cheaper, and environmentally friendly green catalysts is essential to ensuring sustainable social development. As defined by Berzelius in 1835, a catalyst is a substance that can accelerate a chemical reaction without being consumed.

[0003] Broadly speaking, there are two types of catalysts: homogeneous catalysts and heterogeneous catalysts. Homogeneous catalysts possess advantages such as high activity and high selectivity, but separating them from the chemical reaction system presents numerous difficulties and challenges. They cannot be recycled, are costly, and most have poor thermal stability, hindering industrial applications. Therefore, approximately 80% of industrial catalysts are heterogeneous. Heterogeneous catalytic reactions are chemical reactions that occur on the catalyst surface, making them highly sensitive to surface heterogeneity and structure. For example, the catalytic performance of metal catalysts is affected by the coordination of their terminating atoms; surface steps, vacancies, faults, and twin boundaries all influence their catalytic performance.

[0004] Furthermore, the size of metal particles is also a crucial factor affecting performance and contributes to the use of nanoparticles as catalysts. However, due to the presence of surface defects, it is nearly impossible to manufacture two identical nanoparticles. To address this complex issue, single-atom catalysts (SACs) have emerged, where scientists use a single atom as the catalyst, eliminating any surface heterogeneity. In addition to providing high specific activity, single-atom catalysts also reduce costs, which is particularly important for expensive noble metals such as Pt, Pd, Ru, Rh, and Ir, which are crucial for petrochemical industries, pharmaceutical production, environmental protection, and energy applications.

[0005] Single-atom catalysts are almost always prepared on support materials, such as metal oxides, metal carbides, carbonitrides, graphene, and various other two-dimensional (2D) materials. The high efficiency of single-atom catalysts stems from the fact that each atom can catalyze the reaction (100% atomic efficiency). Typically, the interaction between the metal atom and the support enhances charge transfer between them, and they possess unsaturated coordination, unlike metal clusters which lower the activation energy. Single-atom catalysts can be considered similar to heterogeneous catalysts because they are immobilized on a support that can be relatively easily separated and reused. They also resemble homogeneous catalysts because the strong metal-atom-support interactions produce electronic properties similar to organometallic complexes. Single-atom catalysts are superior to other heterogeneous catalysts because they allow for tuning of the coordination environment of individual atoms. This is typically achieved by altering the type of coordinating atoms on the support. In fact, using isolated single atoms is the most efficient way to provide optimal active centers in the corresponding catalyst, thereby maximizing metal atom efficiency while maintaining necessary catalytic performance.

[0006] Single-atom catalysts are a rapidly developing field due to their superior catalytic performance, possessing enormous application potential in industrial catalysis. However, despite increasing research on single-atom catalysis, studies on the growth of crystalline materials using single-atom catalysis remain scarce. Graphene, carbon nanotubes, and transition metal sulfides, with their unique physical and chemical properties, hold broad application prospects in electrochemical energy storage, semiconductors, flexible electronic devices, and optical communications. Therefore, achieving experimentally controlled and precise growth and processing of graphene, carbon nanotubes, or transition metal sulfides at the atomic scale is a crucial problem that urgently needs to be solved, which could accelerate the development of these materials in semiconductors, electronic devices, and energy storage. Summary of the Invention

[0007] To address the aforementioned technical problems, this application provides a metal atom-catalyzed growth method for two-dimensional nanomaterials. This growth method enables control of two-dimensional nanomaterials at the atomic scale, achieving precise processing.

[0008] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution:

[0009] This invention provides a method for the metal atom-catalyzed growth of two-dimensional nanomaterials, characterized in that the preparation method includes the following steps:

[0010] (1) Transfer the two-dimensional nanomaterial to be grown to a microgrid;

[0011] (2) The metal atoms are doped into the two-dimensional nanomaterial by heat treatment;

[0012] (3) The two-dimensional nanomaterials doped with electron beam irradiation are grown.

[0013] In this invention, during the metal atom catalysis of carbon nanotubes, graphene, or monolayer transition metal sulfides, the C atoms and elements contained in the monolayer transition metal sulfides all originate from within the electron microscope. The element supply methods include both active and passive supply. Passive supply is primarily due to the introduction of hydrocarbon contaminants during long-term testing of the transmission electron microscope, which inherently provides a carbon source for the growth of graphene and carbon nanotubes. In active supply, substances containing these elements are introduced. For graphene or carbon nanotube growth, a small amount of alkanes or carbon nanoparticles can be introduced, allowing them to volatilize as a carbon source under the electron beam. For transition metal sulfides, nanoparticles such as MoS2, MoTe2, WSe2, Mo, W, Se, and Te are used. Under the action of an electron beam, they volatilize the corresponding Mo, S, W, and Se elements, which remain in the electron microscope tube. The monolayer transition metal sulfide two-dimensional material sample to be grown is then placed inside, and the two-dimensional material is grown using the catalytic effect of the metal atoms.

[0014] As a preferred technical solution of the present invention, the two-dimensional nanomaterial in step (1) includes any one of carbon nanotubes, graphene or monolayer transition metal sulfides.

[0015] Preferably, the monolayer transition metal sulfide includes any one of MoS2, MoTe2, or WSe2.

[0016] Preferably, the metal atoms include any one or a combination of at least two of tin atoms, copper atoms, chromium atoms, indium atoms, manganese atoms, or vanadium atoms. Typical but non-limiting examples of such combinations include: combinations of tin and copper atoms, combinations of tin and chromium atoms, combinations of tin and indium atoms, combinations of tin and manganese atoms, combinations of tin and vanadium atoms, combinations of copper and chromium atoms, combinations of copper and indium atoms, combinations of copper and manganese atoms, combinations of copper and vanadium atoms, combinations of chromium and indium atoms, combinations of chromium and manganese atoms, combinations of chromium and vanadium atoms, combinations of indium and manganese atoms, combinations of indium and vanadium atoms, or combinations of manganese and vanadium atoms, etc.

[0017] In this invention, two or more metal atoms are used for catalysis in the growth of graphene. When two metals are used for catalytic growth, their catalytic growth effects can be superimposed, which can better control the direction and rate of growth of graphene, carbon nanotubes or transition metal sulfides.

[0018] As a preferred embodiment of the present invention, the method for transferring the carbon nanotubes or graphene to the microgrid includes the following steps:

[0019] (A) Spin-coating a carbon-containing polymer onto the surface of a substrate containing carbon nanotubes or graphene, and allowing it to stand to harden the carbon-containing polymer to obtain a carbon-containing polymer layer.

[0020] (B) The carbon-containing polymer layer is segmented and immersed in an etching solution. After the substrate is dissolved, the carbon nanotubes or graphene are cleaned and transferred onto the microgrid.

[0021] (C) Use vapors of organic solvents to remove residual carbon-containing polymers from the surface of the carbon nanotubes or graphene.

[0022] As a preferred technical solution of the present invention, the carbon-containing polymer in step (A) includes polymethyl methacrylate.

[0023] Preferably, the substrate in step (A) comprises a copper substrate.

[0024] Preferably, the settling time in step (A) is 5 to 10 minutes, such as 5.5 minutes, 6 minutes, 6.5 minutes, 7 minutes, 7.5 minutes, 8 minutes, 8.5 minutes, 9 minutes or 9.5 minutes, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] Preferably, the corrosive liquid in step (B) comprises an ammonium persulfate solution.

[0026] Preferably, the concentration of the corrosive liquid in step (B) is 0.1 to 3M, such as 0.2M, 0.5M, 0.8M, 1M, 1.2M, 1.5M, 1.8M, 2M, 2.2M, 2.5M or 2.8M, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Preferably, the immersion time in the corrosive solution in step (B) is 2 to 12 hours, such as 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours or 11 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, the cleaning method in step (B) includes rinsing with deionized water at least three times.

[0029] Preferably, the vapor of the organic solvent in step (C) includes acetone vapor.

[0030] As a preferred technical solution of the present invention, the method for transferring the monolayer transition metal sulfide to the microgate includes the following steps:

[0031] (a) Spin-coating a carbon-containing polymer onto the surface of a substrate containing a transition metal sulfide, and allowing it to stand to harden the carbon-containing polymer to obtain a carbon-containing polymer layer;

[0032] (b) The carbon-containing polymer layer is segmented and immersed in an etching solution. After the substrate is dissolved, the carbon nanotubes or graphene are cleaned and transferred onto the microgrid.

[0033] (c) Use vapors of organic solvents to remove residual carbon-containing polymers from the surface of the monolayer transition metal sulfide.

[0034] As a preferred technical solution of the present invention, the carbon-containing polymer in step (a) includes polymethyl methacrylate.

[0035] Preferably, the substrate in step (a) comprises a Si / SiO2 substrate.

[0036] Preferably, the settling time in step (a) is 5 to 10 minutes, such as 5.5 minutes, 6 minutes, 6.5 minutes, 7 minutes, 7.5 minutes, 8 minutes, 8.5 minutes, 9 minutes or 9.5 minutes, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] Preferably, the corrosive liquid in step (b) includes an alkaline solution or an acidic solution.

[0038] Preferably, the alkaline solution comprises sodium hydroxide solution and / or potassium hydroxide solution.

[0039] Preferably, the concentration of the alkaline solution is 5 to 20 wt%, such as 6 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, or 18 wt%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] Preferably, the acid solution includes a hydrofluoric acid solution.

[0041] Preferably, the concentration of the acid solution is 5 to 20 wt%, such as 6 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, or 18 wt%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0042] Preferably, the immersion time in the corrosive solution in step (b) is 2 to 12 hours, such as 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours or 11 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] Preferably, the cleaning method in step (b) includes rinsing with deionized water at least three times.

[0044] Preferably, the vapor of the organic solvent in step (c) includes acetone vapor.

[0045] In this invention, the principle of using acetone vapor to remove residual PMMA is that after the acetone vapor comes into contact with the microgrid carrying the sample, it undergoes condensation. After 5-15 acetone droplets fall off the microgrid, the PMMA residue attached to the sample surface will be dissolved by the acetone.

[0046] As a preferred technical solution of the present invention, the heat treatment method in step (2) includes: placing the microgrid and the metal source in two different positions in a tubular container and performing heat treatment.

[0047] As a preferred technical solution of the present invention, the metal source includes any one or a combination of at least two of tin acetylacetone, diphenyltin oxide, chromium acetylacetone, copper acetylacetone, indium acetylacetone, manganese acetylacetone, or vanadium acetylacetone. Typical but non-limiting examples of such combinations include: combinations of tin acetylacetone and chromium acetylacetone, combinations of tin acetylacetone and copper acetylacetone, combinations of tin acetylacetone and indium acetylacetone, combinations of tin acetylacetone and manganese acetylacetone, combinations of tin acetylacetone and vanadium acetylacetone, combinations of chromium acetylacetone and copper acetylacetone, combinations of chromium acetylacetone and indium acetylacetone, combinations of chromium acetylacetone and manganese acetylacetone, combinations of chromium acetylacetone and vanadium acetylacetone, combinations of copper acetylacetone and indium acetylacetone, combinations of copper acetylacetone and manganese acetylacetone, combinations of copper acetylacetone and vanadium acetylacetone, combinations of indium acetylacetone and manganese acetylacetone, combinations of indium acetylacetone and vanadium acetylacetone, or combinations of manganese acetylacetone and vanadium acetylacetone, etc.

[0048] As a preferred technical solution of the present invention, the distance between the microgrid and the metal source in the tubular container is 10 to 50 mm, such as 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm or 55 mm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0049] Preferably, the tubular container includes a quartz tube container.

[0050] Preferably, the tubular container has an inner diameter of 5-10 mm and a length of 100-200 mm. The inner diameter can be 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, or 9.5 mm, etc., and the length can be 110 mm, 120 mm, 130 mm, 140 mm, 150 mm, 160 mm, 170 mm, 180 mm, or 190 mm, etc., but is not limited to the listed values. Other unlisted values ​​within the above ranges are also applicable.

[0051] Preferably, the tubular container is under vacuum during the annealing process, with a vacuum level not exceeding 10.-6 mbar.

[0052] In this invention, after placing the microgrid and metal source in a tubular container, a vacuum pump is used to evacuate the vacuum inside the tubular container to the required value, and a hot melt gun is used to seal the quartz tube.

[0053] Preferably, the temperature of the heat treatment is 200-350℃, such as 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃, 300℃, 310℃, 320℃, 330℃ or 340℃, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0054] Preferably, the heating treatment time is 5 to 24 hours, such as 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, or 23 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0055] As a preferred embodiment of the present invention, the electron beam includes a parallel electron beam or a converging electron beam.

[0056] Preferably, the electron beam irradiation time is 30s to 1h, such as 45s, 60s, 5min, 10min, 20min, 30min or 45min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0057] Preferably, the energy of the electron beam irradiation is 10. 4 ~10 7 A / m 2 For example, 5×10 4 A / m 2 1×10 5 A / m 2 5×10 5 A / m 2 1×10 6 A / m 2 Or 5×10 6 A / m 2 This applies to, but is not limited to, the listed values; other unlisted values ​​within this range also apply.

[0058] Compared with the prior art, the present invention has at least the following beneficial effects:

[0059] (1) This application provides a metal atom catalytic growth method for two-dimensional nanomaterials, which can realize the control of two-dimensional nanomaterials at the atomic scale and achieve precise processing;

[0060] (2) This application provides a metal atom catalytic growth method for two-dimensional nanomaterials. Existing technologies only grow on a macroscopic scale and cannot precisely control the position of atoms. The growth method provided in this application can control the growth of two-dimensional materials at the sub-nanometer atomic scale. This technology lays the foundation for achieving process nodes below 1nm in the semiconductor field in the future. Attached Figure Description

[0061] Figure 1a -d is the HRTEM image of graphene prepared in Example 4 of this invention;

[0062] Figure 2a This is a picture of the substrate (copper foil) before the experiment in Comparative Example 1 of the present invention;

[0063] Figure 2b This is an image of the copper foil after graphene deposition, which is Comparative Example 1 of this invention.

[0064] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0065] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0066] Example 1

[0067] This embodiment provides a metal atom-catalyzed growth method for two-dimensional nanomaterials, the preparation method comprising the following steps:

[0068] (1) Transfer the carbon nanotubes to be grown to the microgrid;

[0069] The method for transferring the carbon nanotubes to the microgrid includes the following steps:

[0070] (A) Spin-coating PMMA onto the surface of a Cu substrate containing carbon nanotubes and allowing it to stand for 5 minutes to harden the PMMA to obtain a PMMA layer;

[0071] (B) The PMMA layer is divided into 3mm×3mm squares and immersed in 0.5M ammonium persulfate solution for 6 hours. After the Cu substrate is dissolved, the carbon nanotubes are washed 4 times with deionized water and transferred to the microgrid.

[0072] (C) Use acetone vapor to remove residual PMMA from the surface of the carbon nanotubes;

[0073] (2) Sn metal atoms are doped into the carbon nanotubes by heat treatment;

[0074] The heat treatment method includes: placing the microgrid and tin acetylacetone at two different positions in a quartz tube (inner diameter 8mm, length 150mm), spaced 20mm apart; and using a vacuum pump to evacuate the inside of the quartz tube to a vacuum level below 10. - 6 mbar, the quartz tube was sealed at the end with a high-temperature hot melt gun and heated at 300℃ for 12 hours;

[0075] (3) The indium-doped carbon nanotubes were grown by irradiating them with an electron beam.

[0076] The electron beam parameters are: ① Voltage: 80kV; ② Electron beam current: 1.1nA; ③ Electron beam dose: 1.8*10 6 A / m 2 ④ Electron beam irradiation duration: 30 min.

[0077] Example 2

[0078] This embodiment provides a metal atom-catalyzed growth method for two-dimensional nanomaterials, the preparation method comprising the following steps:

[0079] (1) Transfer the carbon nanotubes to be grown to the microgrid;

[0080] The method for transferring the carbon nanotubes to the microgrid includes the following steps:

[0081] (A) Spin-coating PMMA onto the surface of a Cu substrate containing carbon nanotubes and allowing it to stand for 10 minutes to harden the PMMA to obtain a PMMA layer;

[0082] (B) The PMMA layer is divided into 3mm×3mm squares and immersed in 0.1M ammonium persulfate solution for 12h. After the Cu substrate is dissolved, the carbon nanotubes are washed three times with deionized water and transferred to the microgrid.

[0083] (C) Use acetone vapor to remove residual PMMA from the surface of the carbon nanotubes;

[0084] (2) Sn metal atoms are doped into carbon nanotubes by heat treatment;

[0085] The heat treatment method includes: placing the microgrid and tin acetylacetone at two different positions in a quartz tube (inner diameter 5mm, length 100mm), spaced 15mm apart; and using a vacuum pump to evacuate the inside of the quartz tube to a vacuum level below 10.- 6 mbar, the quartz tube is sealed at the end with a high-temperature hot melt gun and heated at 200℃ for 24 hours;

[0086] (3) The carbon nanotubes doped with tin acetylacetone were grown by electron beam irradiation;

[0087] The electron beam parameters are: ① Voltage: 80kV; ② Electron beam current: 1.1nA; ③ Electron beam dose: 10 5 A / m 2 ④ Electron beam irradiation duration: 30 min.

[0088] Example 3

[0089] This embodiment provides a metal atom-catalyzed growth method for two-dimensional nanomaterials, the preparation method comprising the following steps:

[0090] (1) Transfer the carbon nanotubes to be grown to the microgrid;

[0091] The method for transferring the carbon nanotubes to the microgrid includes the following steps:

[0092] (A) Spin-coating PMMA onto the surface of a Cu substrate containing carbon nanotubes and allowing it to stand for 5 minutes to harden the PMMA to obtain a PMMA layer;

[0093] (B) The PMMA layer is divided into 3mm×3mm squares and immersed in 3M ammonium persulfate solution for 2 hours. After the Cu substrate is dissolved, the carbon nanotubes are washed 5 times with deionized water and transferred to the microgrid.

[0094] (C) Use acetone vapor to remove residual PMMA from the surface of the carbon nanotubes;

[0095] (2) Sn metal atoms are doped into the carbon nanotubes by heat treatment;

[0096] The heat treatment method includes: placing the microgrid and tin acetylacetone at two different positions in a quartz tube (inner diameter 10 mm, length 200 mm), spaced 50 mm apart; and using a vacuum pump to evacuate the inside of the quartz tube to a vacuum level below 10. - 6 mbar, the quartz tube is sealed at the end with a high temperature hot melt gun and heated at 350℃ for 24 hours;

[0097] (3) The indium-doped carbon nanotubes were grown by irradiating them with an electron beam.

[0098] The electron beam parameters are: ① Voltage: 80kV; ② Electron beam current: 5nA; ③ Electron beam dose: 10 7 A / m2 ④ Electron beam irradiation duration: 0.5 min.

[0099] Example 4

[0100] In this embodiment, the conditions are the same as in Example 1, except that carbon nanotubes are replaced with graphene and tin acetylacetone is replaced with indium acetylacetone.

[0101] Figures 1a-1d These are HRTEM images from the graphene preparation process in this embodiment, showing the behavior of catalytic graphene edge growth as a single indium atom (monomer) diffuses along the edge. Figures a and b show the HRTEM images corresponding to the indium single-atom catalytic growth of graphene at 0 and 2 s, respectively. Figures c and d are HRTEM images with a partial ball-and-stick model, used to further clearly demonstrate and confirm this catalytic growth process. The dashed lines are reference lines indicating the movement positions of indium atoms. Figure 1a In this process, an indium atom is embedded into the corner of the graphene, replacing two carbon atoms and establishing two Sn-C bonds at the graphene edge. Subsequently, the atom migrates upwards after 2 seconds. Simultaneously, four new carbon atoms insert around the indium atom, forming a fully reconstructed serrated edge. In this embodiment, the carbon source for growth is derived from hydrocarbon contaminants within the TEM chamber.

[0102] Example 5

[0103] In this embodiment, the only difference is that carbon nanotubes are replaced with graphene, and tin acetylacetone is replaced with tin acetylacetone and chromium acetylacetone (molar ratio of 1:1). All other conditions are the same as in Example 1.

[0104] Example 6

[0105] This embodiment provides a metal atom-catalyzed growth method for two-dimensional nanomaterials, the preparation method comprising the following steps:

[0106] (1) Transfer the monolayer MoS2 to be grown to the microgrid;

[0107] The method for transferring the monolayer MoS2 to a microgate includes the following steps:

[0108] (A) Spin-coating PMMA onto the surface of a Si / SiO2 substrate containing MoS2 and allowing it to stand for 5 minutes to harden the PMMA to obtain a PMMA layer;

[0109] (B) The PMMA layer is divided into 3mm×3mm squares and immersed in 10wt% sodium hydroxide solution for 6h. After the Si / SiO2 substrate is dissolved, the monolayer MoS2 is washed 4 times with deionized water and transferred to the microgate.

[0110] (C) Use acetone vapor to remove residual PMMA from the surface of the carbon nanotubes;

[0111] (2) Sn metal atoms are doped into the monolayer MoS2 by heat treatment;

[0112] The heat treatment method includes: placing the microgrid and tin acetylacetone at two different positions in a quartz tube (inner diameter 8mm, length 15mm), spaced 20mm apart; and using a vacuum pump to evacuate the inside of the quartz tube to a vacuum level below 10. -6 mbar, the quartz tube was sealed at the end with a high-temperature hot melt gun and heated at 300℃ for 12 hours;

[0113] (3) Growth of the tin-doped MoS2 two-dimensional material by electron beam irradiation;

[0114] The electron beam parameters are: ① Voltage: 80kV; ② Electron beam current: 3nA; ③ Electron beam dose: 10 6 A / m 2 ④ Electron beam irradiation duration: 5 min.

[0115] Example 7

[0116] In this embodiment, all conditions are the same as in Example 6, except that the monolayer MoS2 is replaced with a monolayer MoTe2.

[0117] Example 8

[0118] In this embodiment, all conditions are the same as in embodiment 6, except that the monolayer MoS2 is replaced with a monolayer WSe2.

[0119] Comparative Example 1

[0120] This comparative example provides a method for growing macroscopic graphene, which includes the following steps:

[0121] (1) Clean the copper foil using anhydrous ethanol and acetone;

[0122] (2) Evacuate the CVD system to reduce the influence of other gases on the furnace tube, and the pressure is below 0.2 Pa;

[0123] (3) Introduce 5 sccm of H2 and 450 sccm of Ar gas, raise the temperature to above 1060℃, and maintain for 60 min;

[0124] (4) Introduce 2 sccm of CH4 and maintain for 15 min;

[0125] (5) Quickly reduce the temperature to room temperature and remove the sample.

[0126] The samples prepared by it are as follows Figure 2a and2b As shown, Figure 2a This is a picture of the substrate (copper foil) before the experiment. Figure 2b The images show a comparison of copper foil after graphene deposition. The surface brightness is significantly increased. Further Raman spectroscopy tests confirm that monolayer graphene has been prepared on the surface of the copper foil. This method is suitable for large-area graphene synthesis, but it cannot achieve atomic-level precision control over the growth.

[0127] The applicant declares that the detailed structural features of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components selected in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0128] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0129] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0130] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for metal-atomic catalytic growth of two-dimensional nanomaterials, characterized in that, The method includes the following steps: (1) Transfer the two-dimensional nanomaterial to be grown to a microgrid; (2) The metal atoms are doped into the two-dimensional nanomaterial by heat treatment; The heat treatment method includes: placing the microgrid and the metal source at two different locations in a tubular container and performing heat treatment; the distance between the microgrid and the metal source in the tubular container is 10~50 mm; (3) The two-dimensional nanomaterials doped with electron beam irradiation are grown by the catalytic effect of metal atoms; the two-dimensional nanomaterials in step (1) include either carbon nanotubes or graphene; The carbon source for growth comes from hydrocarbon contaminants in the TEM chamber; The metal atoms are selected from indium atoms; The method for transferring the carbon nanotubes or graphene to the microgrid includes the following steps: (A) Spin-coating a carbon-containing polymer onto the surface of a substrate containing carbon nanotubes or graphene, and allowing it to stand to harden the carbon-containing polymer to obtain a carbon-containing polymer layer; (B) The carbon-containing polymer layer is segmented and immersed in an etching solution. After the substrate is dissolved, the carbon nanotubes or graphene are cleaned and transferred onto the microgrid. (C) Use vapors of organic solvents to remove residual carbon-containing polymers from the surface of the carbon nanotubes or graphene.

2. The growth method according to claim 1, characterized in that, The carbon-containing polymer in step (A) includes polymethyl methacrylate.

3. The growth method according to claim 1, characterized in that, The substrate in step (A) includes a copper substrate.

4. The growth method according to claim 1, characterized in that, The settling time in step (A) is 5 to 10 minutes.

5. The growth method according to claim 1, characterized in that, The corrosive solution in step (B) includes an ammonium persulfate solution.

6. The growth method according to claim 1, characterized in that, The concentration of the corrosive solution in step (B) is 0.1~3M.

7. The growth method according to claim 1, characterized in that, Step (B) involves immersing the sample in the corrosive solution for 2 to 12 hours.

8. The growth method according to claim 1, characterized in that, The cleaning method described in step (B) includes rinsing with deionized water at least three times.

9. The growth method according to claim 1, characterized in that, The vapor of the organic solvent in step (C) includes acetone vapor.

10. The growth method according to claim 1, characterized in that, The metal source is selected from indium acetylacetone.

11. The growth method according to claim 1, characterized in that, The tubular container includes a quartz tube container.

12. The growth method according to claim 1, characterized in that, The tubular container has an inner diameter of 5-10 mm and a length of 100-200 mm.

13. The growth method according to claim 1, characterized in that, The heat treatment annealing process is in a vacuum state inside the tubular container, and the vacuum degree is not higher than 10 -6 mbar.

14. The growth method according to claim 1, characterized in that, The temperature of the heat treatment is 200~350 ℃.

15. The growth method according to claim 1, characterized in that, The heat treatment time is 5~24 h.

16. The growth method according to claim 1, characterized in that, The electron beam includes a parallel electron beam or a converging electron beam.

Images