S-region metal two-dimensional material and preparation method thereof

Abstract

The invention relates to an S-region metal two-dimensional material and a preparation method thereof, and belongs to the field of low-dimensional materials. The preparation method comprises the following steps: (1) mixing a metal precursor and S-zone metal salt according to a set proportion, uniformly grinding, then placing between two substrates in a central reaction zone of heating equipment, and controlling the reaction temperature to be 500-1100 DEG C; (2) putting a chalcogen precursor in an upstream area of heating equipment, keeping the distance between the chalcogen precursor and the central reaction area at 0-20cm, introducing inert gas into the heating equipment as carrier gas, and mixing reducing gas according to the type of the chalcogen; and (3) chalcogen steam generated in the upstream area is conveyed to a central reaction area through carrier gas, the chalcogen steam reacts with a mixture of a metal precursor and S-area metal salt at the high temperature of 500-1100 DEG C, and finally the S-area metal two-dimensional material is prepared. The S-region metal two-dimensional material prepared by the method has high crystal quality.

Description

Technical Field

[0001] This invention relates to the technical field of low-dimensional materials, specifically to an S-region metallic two-dimensional material and its preparation method. Background Technology

[0002] Since the discovery of graphene, two-dimensional materials have provided an ideal platform for exploring exotic physical properties and potential applications. To date, various types of two-dimensional materials, including elemental alkenes, transition metal chalcogenides, transition metal phosphorus chalcogenides, and layered metal halides, have been extensively studied. Recently, theoretical calculations have predicted over 4000 types of two-dimensional materials. However, the number of synthesizable two-dimensional materials with exotic physical properties within these systems remains limited. Exploring novel two-dimensional materials is crucial for discovering unexpected physical properties and expanding their applications.

[0003] S-block metal (alkali metal / alkaline earth metal) based materials offer new opportunities to overcome the above limitations due to their unique electronic structure, low lattice symmetry, and rich structure, resulting in a series of physical properties such as anisotropic optics, magnetism, and superconductivity.

[0004] However, there are few reports on S-block metal two-dimensional materials for the following reasons: (1) S-block metals have extremely high chemical activity, which makes it difficult for them to participate in the reaction to form two-dimensional materials; (2) Most S-block metal-based compounds are ternary components, so the preparation of their two-dimensional materials is more challenging; (3) In the process of chemical vapor deposition, when transition metal elements and S-block metal elements coexist, due to their different vapor pressures, the resulting two-dimensional materials are mostly binary transition metal chalcogenides.

[0005] Therefore, solving the above challenges and controllably synthesizing S-block metallic two-dimensional materials is of great significance for the development of low-dimensional materials. Summary of the Invention

[0006] To address all or part of the aforementioned technical problems, the present invention aims to provide a universal S-block metallic two-dimensional material and its preparation method, which exhibits high crystallinity. In this invention, a metal precursor and an S-block metal salt are thoroughly ground and mixed in a predetermined ratio, and a universal S-block metallic two-dimensional material is prepared using chemical vapor deposition.

[0007] According to one aspect of the present invention, a method for preparing an S-region metallic two-dimensional material is provided, the method comprising the following steps:

[0008] Step (1): Mix the metal precursor and S-region metal salt in a set ratio and grind them evenly. Then place them between two substrates in the central reaction area of ​​the heating device and control the reaction temperature at 500-1100℃.

[0009] Step (2): Place the chalcogenide precursor in the upstream area of ​​the heating device, with a distance of 0-20 cm from the central reaction zone, and introduce an inert gas into the heating device as a carrier gas, and mix a reducing gas according to the type of chalcogenide.

[0010] Step (3): The chalcogenide vapor generated in the upstream region is transported to the central reaction region by a carrier gas and reacted with the mixture of metal precursor and S-region metal salt under high temperature conditions (500-1100℃) to finally obtain the S-region metal two-dimensional material.

[0011] In some embodiments, the metal precursor includes any one or any mixture of elemental metals such as titanium, tantalum, vanadium, chromium, iron, niobium, and indium, metal chlorides, and metal oxides.

[0012] In some embodiments, the sulfide precursor includes any one of elemental sulfur, elemental selenium, and elemental tellurium.

[0013] In some embodiments, the S-zone metal salt includes any one or any mixture of alkali metal / alkaline earth metal halides / sulfates / nitrates / carbonates with a melting point below 1000°C.

[0014] In some embodiments, the molar ratio of the metal precursor to the S-region metal salt is in the range of 1:1 to 1:3.

[0015] In some embodiments, the mass ratio of the chalcogenide precursor to the metal precursor is in the range of 10:1 to 100:1.

[0016] In some embodiments, in step (2), the inert gas in the carrier gas includes either argon or nitrogen or any mixture thereof, and the carrier gas also includes the reducing gas hydrogen, with the ratio of inert gas to hydrogen in the range of 10:1 to 2:1.

[0017] In some embodiments, in step (3), under the action of a carrier gas, the sulfide precursor vapor reacts with the metal precursor and the S-region metal salt mixture in the central temperature zone.

[0018] According to another aspect of the present invention, an S-region metallic two-dimensional material is provided. The S-region metallic two-dimensional material is prepared according to the preparation method described in the foregoing aspect.

[0019] In embodiments of the present invention, in order to form the highly crystalline S-block metal two-dimensional material, it is necessary to simultaneously ensure the reaction temperature, the supply of chalcogenide precursors, and the participation of the S-block metal salt in the central temperature zone. Specifically:

[0020] (1) In the embodiments of the present invention, S-region metal salt and metal precursor are mixed in proportion and ground thoroughly to reduce the melting point of the metal precursor. At the same time, it acts as a reaction catalyst to form a liquid melt containing S-region metal at high temperature, promote the reaction, and then self-assemble and grow into S-region metal two-dimensional material.

[0021] (2) In embodiments of the present invention, the reaction temperature needs to be controlled between 500-1100℃. This temperature range is mainly adjusted based on the melting points of the S-region metal salt and the metal precursor. The reaction temperature must ensure that a liquid melt can be formed, thereby generating high-quality S-region metal two-dimensional materials. When the reaction temperature is below 500℃, it may be impossible to overcome the energy barrier required to form the S-region metal two-dimensional material; while when the reaction temperature is much higher than the melting point of the S-region metal salt, the chemical reaction has already occurred at a lower temperature, and high temperature can easily cause etching. Therefore, the heater temperature range needs to be set to 500-1100℃.

[0022] (3) In embodiments of the present invention, it is necessary to ensure that the central temperature zone has a sufficient chalcogenide precursor atmosphere when the reaction proceeds to the high-temperature stage, so as to provide the chalcogenide source required for a class of S-block metallic two-dimensional materials. Therefore, the temperature of the central temperature zone needs to be controlled at 500-1100℃, and the chalcogenide precursor is placed upstream of the central temperature zone, 0-20cm away. Inert gas and reducing gas are introduced as carrier gases depending on the reaction conditions to transport the chalcogenide precursor vapor to the central temperature zone. The position of the chalcogenide precursor determines its participation in the reaction and needs to be adjusted according to the temperature of the central temperature zone to control the supply of the chalcogenide precursor. When the chalcogenide precursor is too far from the central temperature zone, its vapor volatilizes less and participates in the reaction later. Under the condition of insufficient chalcogenide, it is difficult to form the target S-region metal two-dimensional material. When it is too close to the central temperature zone, a large amount of chalcogenide precursor vapor will volatilize and participate in the reaction too early, causing the reaction to occur prematurely at a lower temperature. The product formed will show etching or even decomposition after being heated at a higher temperature.

[0023] (4) The embodiments of the present invention require the reaction to be carried out under suitable carrier gas conditions. Whether to introduce a reducing gas depends on the reactivity of the chalcogenide precursor. The inert gas is usually around 100 sccm, and the hydrogen is adjusted accordingly within the range of 10:1 to 2:1. Within this range, the inert gas can provide suitable chalcogenide precursor vapor for the reaction. If the inert gas is too high, there will be too much chalcogenide precursor supply, and the target product will be too thick; conversely, if the supply is insufficient, the target product size will be too small. If the amount of hydrogen is too high, it will easily etch the target product; conversely, if the precursor activity is insufficient, the reaction will be incomplete, which is not conducive to the crystallization of the target product.

[0024] The S-region metallic two-dimensional materials and their preparation methods provided by the embodiments of the present invention have at least one or a portion of the following advantages:

[0025] (1) The present invention provides a general S-region metallic two-dimensional material and its preparation method, which are simple, efficient and convenient.

[0026] (2) The preparation method has good reproducibility and can obtain a class of S-region metal two-dimensional materials with controllable crystal structure and surface morphology;

[0027] (3) The embodiments of the present invention can be directly grown on the surface of various substrates such as Si / SiO2, sapphire, mica, highly oriented pyrolytic graphite substrate, Au, etc., thereby obtaining large-size thin-layer S-region metal two-dimensional materials, and directly performing property testing, avoiding complex processes such as transfer that damage the inherent properties of S-region metal two-dimensional materials.

[0028] (4) The embodiments of the present invention provide a new approach for the universal preparation and property study of a class of S-region metallic two-dimensional materials. Attached Figure Description

[0029] These and / or other aspects and advantages of the present invention will become apparent and readily understood from the following description of preferred embodiments taken in conjunction with the accompanying drawings, in which:

[0030] Figure 1 This is a flowchart illustrating a method for preparing a type of S-region metallic two-dimensional material according to an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of an apparatus for preparing a type of S-region metallic two-dimensional material according to an embodiment of the present invention;

[0032] Figures 3a-3d The images shown are optical photographs, Raman spectra, cross-sectional high-resolution spherical aberration transmission electron microscopy images, and corresponding selected area electron diffraction images of the representative S-region metallic two-dimensional material CsNbS2 prepared in Example 1 of this invention.

[0033] Figures 4a-4d The images show optical photographs, Raman spectra, cross-sectional high-resolution spherical aberration transmission electron microscopy images, and corresponding selected area electron diffraction images of KCr5Te8, a representative S-region metallic two-dimensional material prepared in Example 2 of this invention.

[0034] Figures 5a-5d The images show optical photographs, Raman spectra, cross-sectional high-resolution spherical aberration transmission electron microscopy images, and corresponding selected area electron diffraction images of the representative S-region metallic two-dimensional material NbS2-BaS2 prepared in Example 3 of this invention. Detailed Implementation

[0035] The features of the present invention are further illustrated below through specific embodiments. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall concept of the present invention and should not be construed as a limitation thereof.

[0036] In an embodiment of the present invention, a method for preparing an S-region metallic two-dimensional material is provided. The preparation method includes the following steps:

[0037] Step (1): Mix the metal precursor and S-region metal salt in a set ratio and grind them evenly. Then place them between two substrates in the central reaction area of ​​the heating device and control the reaction temperature at 500-1100℃.

[0038] Step (2): Place the chalcogenide precursor in the upstream area of ​​the heating device, with a distance of 0-20 cm from the central reaction zone, and introduce an inert gas into the heating device as a carrier gas. Mix a reducing gas according to the type of chalcogenide, for example, in a certain proportion.

[0039] Step (3): The chalcogenide vapor generated in the upstream region is transported to the central reaction region by a carrier gas and reacted with the mixture of metal precursor and S-block metal salt under high temperature conditions (500-1100℃) to finally obtain a type of S-block metal two-dimensional material.

[0040] Specifically, the metal precursor and S-block metal salt are thoroughly ground and mixed in a certain proportion, and placed in the central temperature zone of the heater, with a reaction temperature range of 500-1100℃. The chalcogen element precursor is placed in the upstream region of the heater, 0-20 cm away from the central temperature zone. An inert gas is introduced into the heater as a carrier gas, and a certain proportion of reducing gas is mixed in as needed for the reaction. The carrier gas transports the chalcogen element precursor vapor to the central temperature zone, where it reacts with the mixture of metal precursor and S-block metal salt in the central temperature zone under high temperature conditions (500-1100℃) to obtain a type of S-block metal two-dimensional material.

[0041] like Figure 1 As shown, the method for preparing a type of S-region metallic two-dimensional material provided in this embodiment of the invention includes:

[0042] The metal precursor and the S-zone metal salt are thoroughly ground and mixed in a certain proportion, and then placed in the central temperature zone of the heater. The reaction temperature range of 500-1100℃ is set in the central temperature zone.

[0043] The sulfide precursor is placed in the upstream region of the heater, 0-20 cm away from the central temperature zone;

[0044] An inert gas is introduced into the heater as a carrier gas, and a reducing gas is mixed in as needed for the reaction. The carrier gas transports the chalcogen element precursor vapor to the central temperature zone, where it reacts with the metal precursor and S-block metal salt mixture in the central temperature zone under high temperature conditions (500-1100℃) to obtain a type of S-block metal two-dimensional material.

[0045] In embodiments of this invention, a metal precursor and an S-block metal salt are thoroughly ground and mixed in a certain proportion, and then placed in the central temperature zone of a heater. A chalcogenide precursor is placed upstream of the heater, 0-20 cm from the central temperature zone. When the central temperature zone reaches 500-1100°C, the S-block metal salt lowers the melting point of the metal precursor, forming a liquid melt at high temperature, thus providing a template for the self-assembly of low-dimensional S-block metal two-dimensional materials. Simultaneously, at this reaction temperature, the chalcogenide precursor reaches the central temperature zone under the action of a carrier gas, providing a chalcogenide source required for S-block metal two-dimensional materials. This temperature also provides sufficient energy for the chemical reaction, facilitating the self-assembly growth of the target product in the liquid melt, thereby obtaining a class of S-block metal two-dimensional materials.

[0046] In embodiments of the present invention, in order to form this type of highly crystalline S-block metallic two-dimensional material, it is necessary to simultaneously ensure the reaction temperature, the supply of chalcogenide precursors, and the participation of S-block metal salts in the central temperature region. Specifically:

[0047] In embodiments of the present invention, S-region metal salts and metal precursors are mixed in proportion and thoroughly ground to lower the melting point of the metal precursors. Simultaneously, the precursors act as a reaction catalyst to form a liquid melt containing S-region metals at high temperature, promoting the reaction and subsequently self-assembling and growing into two-dimensional S-region metal materials.

[0048] In embodiments of this invention, the reaction temperature needs to be controlled between 500-1100°C. This temperature range is mainly adjusted based on the melting points of the S-region metal salt and the metal precursor. The reaction temperature must ensure the formation of a liquid melt, thereby generating high-quality S-region two-dimensional metal materials. At reaction temperatures below 500°C, it may be impossible to overcome the energy barrier required to form the S-region two-dimensional metal material; while at reaction temperatures much higher than the melting point of the S-region metal salt, the chemical reaction occurs at a lower temperature, and high temperatures can easily cause etching. Therefore, the heater temperature range needs to be set to 500-1100°C.

[0049] In embodiments of this invention, it is necessary to ensure that the central temperature zone has a sufficient atmosphere of chalcogenide precursors during the high-temperature stage of the reaction, in order to provide the chalcogenide source required for a class of S-block metallic two-dimensional materials. To this end, the temperature of the central temperature zone needs to be controlled at 500-1100°C. The chalcogenide precursor is placed upstream of the central temperature zone, 0-20 cm away. Inert and reducing gases are introduced as carrier gases, depending on the reaction progress, to transport the chalcogenide precursor vapor to the central temperature zone. The position of the chalcogenide precursor determines its participation in the reaction and needs to be adjusted according to the temperature of the central temperature zone to control the supply of chalcogenide precursors. When the chalcogenide precursor is too far from the central temperature zone, its vapor volatilizes less and participates in the reaction later. Under the condition of insufficient chalcogenide, it is difficult to form the target S-region metal two-dimensional material. When it is too close to the central temperature zone, a large amount of chalcogenide precursor vapor will volatilize and participate in the reaction too early, causing the reaction to occur prematurely at a lower temperature. The product formed will show etching or even decomposition after being heated at a higher temperature.

[0050] In embodiments of this invention, the reaction needs to be carried out under suitable carrier gas conditions. Whether to introduce a reducing gas depends on the reactivity of the chalcogenide precursor. The inert gas concentration is typically around 100 sccm, while the hydrogen ratio is adjusted accordingly within the range of 10:1 to 2:1. Within this range, the inert gas can provide a suitable amount of chalcogenide precursor vapor for the reaction. If the concentration is too high, there will be an excessive supply of chalcogenide precursor, resulting in an overly thick target product; conversely, if the supply is insufficient, the target product size will be too small. If the amount of hydrogen is too high, it can easily etch the target product; conversely, insufficient precursor activity will lead to incomplete reaction, which is not conducive to the crystallization of the target product.

[0051] like Figure 2 As shown, the embodiments of the present invention combine the temperature of the heater's central temperature zone, the S-region metal salt, and the metal precursor to ultimately obtain a type of S-region metal two-dimensional material.

[0052] Specifically, the metal precursor includes any one or any mixture of elemental metals, metal chlorides, and metal oxides of titanium, tantalum, vanadium, chromium, iron, niobium, and indium.

[0053] In one example, the chalcogenide precursor includes any one of elemental sulfur, elemental selenium, and elemental tellurium.

[0054] In one example, S-block metal salts include any one or any mixture of alkali metal / alkaline earth metal halides / sulfates / nitrates / carbonates with melting points below 1000°C.

[0055] In one example, the molar ratio of the metal precursor to the S-block metal salt is in the range of 1:1 to 1:3.

[0056] In one example, the mass ratio of chalcogenide precursor to metal precursor ranges from 10:1 to 100:1.

[0057] In one example, the inert gas in the carrier gas includes either argon or nitrogen or any mixture thereof, and the carrier gas also includes the reducing gas hydrogen, with the ratio of inert gas to hydrogen ranging from 10:1 to 2:1.

[0058] In some embodiments of the present invention, under the action of a carrier gas, the above-mentioned chalcogen element precursor vapor reacts with a mixture of metal precursor and S-block metal salt in the central temperature region, thereby obtaining a type of S-block metal two-dimensional material.

[0059] The embodiments of the present invention will now be described in detail with reference to specific examples and accompanying drawings. Those skilled in the art should understand that the present invention is not limited to the specific embodiments, and reasonable modifications can be made after understanding the concept of the present invention.

[0060] Example 1

[0061] A heater was used as the reaction apparatus, employing a quartz tube with a length of 120 cm, an outer diameter of 2.5 cm, and a wall thickness of 2 mm. Nb₂O₅ powder and CsCl were uniformly ground in a 1:2 molar ratio, mixed, and sandwiched between two silicon wafers to form a sandwich structure. An alumina boat was used as a carrier and placed in the central temperature zone of the heater. Approximately 0.3 g of sulfur powder was then weighed and placed in the quartz boat, positioned 9 cm upstream of the central temperature zone. The temperature of the central temperature zone was set to 780 °C, with a heating rate of 50 °C / min and a holding time of 5 min. Argon was used as the carrier gas during the reaction at a concentration of 100 sccm until the heater cooled to room temperature. This yielded the desired CsNbS₂ material. Figure 3a It can be seen that the CsNbS2 obtained in Example 1 exhibits a hexagonal nanosheet morphology with sharp edges and high crystallinity. For example... Figure 3b As shown, the Raman characteristic peaks of CsNbS2 are located at 339 and 377 cm⁻¹. -1 The Z-direction cross-section of CsNbS2 crystal was obtained using focused ion beam technology, and its atomic-scale crystal structure was further characterized using high-resolution spherical aberration transmission electron microscopy. The results are as follows: Figure 3c and Figure 3d As shown, the grown material consists of zero-dimensional Cs atoms between layers and periodic NbS2 layers. The interplanar spacing of the (001) crystal plane is 0.91 nm, and the corresponding selected area electron diffraction confirms its single crystal characteristics.

[0062] Example 2

[0063] A heater was used as the reaction apparatus, employing a quartz tube with a length of 120 cm, an outer diameter of 2.5 cm, and a wall thickness of 2 mm. Cr₂O₃ powder and KCl were uniformly ground in a molar ratio of 1:2:3, mixed, and sandwiched between two silicon wafers to form a sandwich structure. An alumina boat was used as a carrier and placed in the central temperature zone of the heater. Approximately 0.3 g of tellurium powder was then weighed and placed in the quartz boat as a tellurium precursor, positioned 8 cm upstream of the central temperature zone. The temperature of the central temperature zone was set to 880 °C, with a heating rate of 50 °C / min and a holding time of 5 min. During the reaction, a hydrogen-argon mixture was used as the carrier gas, with argon at 100 sccm and hydrogen at 10 sccm. After the reaction, the hydrogen gas was turned off, while the argon gas was kept constant until the heater cooled to room temperature. This yielded the desired KCr₅Te₈ material. Figure 4a It can be seen that the KCr5Te8 obtained in Example 2 exhibits a nanoribbon morphology with sharp edges, demonstrating high crystallinity. The characteristic peaks of the KCr5Te8 crystal were obtained using Raman spectroscopy, and the results are as follows... Figure 4b As shown, the Raman spectrum of KCr5Te8 includes two distinct characteristic peaks, with a peak at 119 cm⁻¹. -1 and 139cm -1 The Z-direction cross-section of KCr5Te8 crystal was obtained using focused ion beam technology, and its atomic-scale crystal structure was further characterized using high-resolution spherical aberration transmission electron microscopy. The results are as follows: Figure 4c and Figure 4d As shown, the grown material consists of zero-dimensional K atoms, one-dimensional CrTe chains and two-dimensional CrTe2 layers between layers. The interplanar spacing of the (001) crystal plane is 0.973 nm. The corresponding selected area electron diffraction confirms its single crystal characteristics.

[0064] Example 3

[0065] A heater was used as the reaction apparatus, employing a quartz tube with a length of 120 cm, an outer diameter of 2.5 cm, and a wall thickness of 2 mm. Nb₂O₅ powder and BaCl were uniformly ground in a 1:3 molar ratio, mixed, and sandwiched between two silicon wafers to form a sandwich structure. An alumina boat was used as a carrier and placed in the central temperature zone of the heater. Approximately 0.3 g of sulfur powder was then weighed and placed in the quartz boat, positioned 9 cm upstream of the central temperature zone. The temperature of the central temperature zone was set to 1000 °C, with a heating rate of 50 °C / min and a holding time of 10 min. During the reaction, an argon-hydrogen mixture was used as the carrier gas, with argon at 100 sccm and hydrogen at 10 sccm. After the reaction, the hydrogen gas was turned off, while the argon gas was kept constant until the heater cooled to room temperature. This yielded the desired NbS₂-BaS₂ material. Figure 5a It can be seen that the NbS2-BaS2 obtained in Example 2 exhibits a hexagonal nanosheet morphology with sharp edges and high crystallinity. The characteristic peaks of the NbS2-BaS2 crystal were obtained using Raman spectroscopy, and the results are as follows: Figure 5b As shown, the Raman spectrum of NbS2-BaS2 includes three distinct characteristic peaks, with a peak at 155 cm⁻¹. -1 344cm -1 and 385cm -1 The Z-direction cross-section of the NbS2-BaS2 crystal was obtained using focused ion beam technology, and its atomic-scale crystal structure was further characterized using high-resolution spherical aberration transmission electron microscopy. The results are as follows: Figure 5c and Figure 5d As shown, the grown material is a superlattice composed of two-dimensional NbS2 and two-dimensional BaS2, with an interplanar spacing of 0.56 nm for the (001) crystal plane. The corresponding selected area electron diffraction confirms its single crystal characteristics.

[0066] In summary, the embodiments of the present invention have yielded a class of S-region metallic two-dimensional materials. The proposed preparation method is simple, has good repeatability and controllability, and is conducive to further research on the novel physical properties of this class of S-region metallic two-dimensional materials.

[0067] The S-region metallic two-dimensional materials and their preparation methods provided by the embodiments of the present invention have at least one or a portion of the following advantages:

[0068] (1) The present invention provides a general S-region metallic two-dimensional material and its preparation method, which are simple, efficient and convenient.

[0069] (2) The preparation method has good reproducibility and can obtain a class of S-region metal two-dimensional materials with controllable crystal structure and surface morphology;

[0070] (3) The embodiments of the present invention can be directly grown on the surface of various substrates such as Si / SiO2, sapphire, mica, highly oriented pyrolytic graphite substrate, Au, etc., thereby obtaining large-size thin-layer S-region metal two-dimensional materials, and directly performing property testing, avoiding complex processes such as transfer that damage the inherent properties of S-region metal two-dimensional materials.

[0071] (4) The embodiments of the present invention provide a new approach for the universal preparation and property study of a class of S-region metallic two-dimensional materials.

[0072] While some embodiments of the present general inventive concept have been shown and described, those skilled in the art will understand that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for preparing an S-region metallic two-dimensional material, wherein, The preparation method includes the following steps: Step (1): Mix the metal precursor and S-region metal salt in a set ratio and grind them evenly. Then place them between two substrates in the central reaction area of ​​the heating device and control the reaction temperature at 500-1100℃. Step (2): Place the sulfide precursor in the upstream area of ​​the heating device, with a distance of 0-20 cm from the central reaction zone, and introduce an inert gas into the heating device as a carrier gas, according to the sulfide mixed reducing gas; Step (3): The chalcogen element vapor generated in the upstream region is transported to the central reaction zone by a carrier gas, and reacted with the mixture of metal precursor and S-region metal salt under high temperature conditions of 500-1100℃, and finally the S-region metal two-dimensional material is obtained.

2. The method for preparing S-region metallic two-dimensional materials according to claim 1, characterized in that, The metal precursor includes any one or any mixture of elemental metals, metal chlorides, and metal oxides of titanium, tantalum, vanadium, chromium, iron, niobium, and indium.

3. The method for preparing S-region metallic two-dimensional materials according to claim 2, characterized in that, The chalcogenide precursors include any one of elemental sulfur, elemental selenium, and elemental tellurium.

4. The method for preparing S-region metallic two-dimensional materials according to claim 3, characterized in that, The S-zone metal salts include any one or any mixture thereof of alkali metal / alkaline earth metal halides / sulfates / nitrates / carbonates with a melting point below 1000°C.

5. The method for preparing S-region metallic two-dimensional materials according to claim 4, characterized in that, The molar ratio of the metal precursor to the S-region metal salt is in the range of 1:1 to 1:

3.

6. The method for preparing S-region metallic two-dimensional materials according to claim 5, characterized in that, The mass ratio of the chalcogenide precursor to the metal precursor is in the range of 10:1 to 100:

1.

7. The method for preparing the S-region metallic two-dimensional material according to any one of claims 1-6, characterized in that, In step (2), the inert gas in the carrier gas includes either argon or nitrogen or any mixture thereof.

8. The method for preparing S-region metallic two-dimensional materials according to claim 7, characterized in that, The carrier gas also includes hydrogen, a reducing gas, and the ratio of inert gas to hydrogen is in the range of 10:1 to 2:

1.

9. The method for preparing S-region metallic two-dimensional materials according to claim 8, characterized in that, In step (3), under the action of the carrier gas, the sulfide precursor vapor reacts with the metal precursor and the S-region metal salt mixture in the central temperature zone.

10. An S-region metallic two-dimensional material, wherein, The S-region metallic two-dimensional material is prepared by the preparation method according to any one of claims 1-9.

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