A method for in-situ preparation of gallium oxide nanostructures on a metal substrate

Abstract

The application provides a method for in-situ preparation of gallium oxide nanostructure on a metal substrate, and the method comprises the following steps: (1) coating molten gallium on the surface of the metal substrate, and performing one-step heat treatment to form a solid alloy phase; (2) under the action of a catalyst, the surface of the solid alloy phase is subjected to two-step heat treatment to obtain the gallium oxide nanostructure on the surface of the metal substrate, the method can quickly obtain a gallium oxide / metal substrate heterostructure, the gallium oxide nanostructure on the surface of the metal substrate is uniformly distributed, and the gallium oxide nanostructure can be prepared in a large area to meet different requirements. The heterostructure has great application potential in the aspects of optoelectronic devices, sensors, photocatalytic environmental purification and wide-wavelength absorption.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor materials, and relates to a method for in-situ preparation of gallium oxide nanostructures on a metal substrate. BACKGROUND

[0002] As a kind of wide band gap semiconductor (E g ≈4.8eV), gallium oxide nanostructures, especially β-Ga2O3 nanostructures, have been widely concerned and applied in the fields of photocatalytic environmental purification, solar blind detection, gas detector and semiconductor chip, etc. due to their high specific surface area, strong adsorption capacity, high chemical / thermal stability and unique photoelectric properties. Since the band gap of gallium oxide is relatively wide, it only responds to ultraviolet light. In order to expand the practical application field, the preparation of β-Ga2O3 / metal heterostructure has become one of the effective strategies. The combination of Ga2O3 nanostructures and metal nanostructures (such as Au and Ag) can promote the charge separation and collection process, thereby providing a new solution for developing advanced photocatalysts for removing dyes, organic pollutants and heavy metals. However, it is still a challenge to quickly build high-quality semiconductor-metal heterostructures with high photocatalytic activity and stability.

[0003] Liquid metal, as a new type of low melting point metal, has attracted extensive attention in many research fields in recent years due to its unique physicochemical properties. Among them, metallic gallium can exist in a liquid state near room temperature, can be processed at a relatively low temperature, and can easily alloy with other metals to obtain unique properties. In recent years, liquid gallium has shown great potential in the synthesis of gallium-based compounds, especially at relatively low synthesis temperatures. However, the obtained gallium oxide is usually a two-dimensional thin layer or flake structure, and the synthesis of Ga2O3 nanowires with one-dimensional nanostructure is still lacking.

[0004] Ga2O3 nanostructures are usually prepared by several classic methods (such as carbothermal reduction, chemical vapor deposition (CVD), physical evaporation, molecular beam epitaxy and decomposition of organometallic precursors) on SiO2 or sapphire substrates through gas-liquid-solid (VLS) or gas-solid (VS) mechanisms.

[0005] CN114436322A discloses a gallium oxide nano material, a preparation method and application thereof. The preparation method of the gallium oxide nano material comprises the following steps: a) PVP-K30 and PVP-K90 are added to a mixed solution of ethanol, acetic acid and dimethylformamide for mixing, and then hydrous gallium nitrate is added for dispersion to obtain an electrospinning solution; b) the electrospinning solution obtained in step a) is electrospun to obtain a gallium nitrate PVP mixed material; and c) the gallium nitrate PVP mixed material obtained in step b) is dried and then annealed to obtain the gallium oxide nano material.

[0006] CN108821331A discloses a preparation method of gallium oxide nanorods and a product, and belongs to the technical field of nanomaterials. The method mainly utilizes a chemical vapor deposition method, and through control of process conditions, finally, gallium oxide nanorods with uniform diameters are prepared.

[0007] The above method usually involves high temperature (usually 800-1000℃), and these substrates can only provide limited area for the preparation of nanostructures (such as nanowires), which brings difficulties to further large-scale production. Therefore, it is of great significance to develop a simple and efficient method for preparing Ga2O3 nanostructures. SUMMARY

[0008] The purpose of the present application is to provide a method for in-situ preparation of gallium oxide nanostructures on a metal substrate. The metal gallium used in the present application can alloy with the solid metal substrate to form intermetallic compounds, and the nanostructures can be prepared by heat treatment. The nanostructures can be uniformly distributed on the surface area of the brushed liquid gallium. This unique microstructure has great application potential in the fields of optoelectronic devices, sensors, photocatalytic environmental purification, and wide wavelength absorption.

[0009] To achieve the purpose of the present application, the following technical solutions are adopted:

[0010] The present application provides a method for in-situ preparation of gallium oxide nanostructures on a metal substrate, which comprises the following steps:

[0011] (1) coating molten gallium on the surface of the metal substrate, and performing one-step heat treatment to form a solid alloy phase;

[0012] (2) under the action of a catalyst, the surface of the solid alloy phase is subjected to two-step heat treatment to obtain the gallium oxide nanostructures on the surface of the metal substrate.

[0013] The present application realizes the uniform preparation of gallium oxide nanostructures on the metal substrate through two-step heat treatment. Compared with traditional carbon thermal reduction, chemical vapor deposition (CVD), physical evaporation, and molecular beam epitaxy, the preparation temperature and time are greatly reduced.

[0014] Preferably, the material of the metal substrate in step (1) comprises any one or a combination of at least two of Au, Pt, Ag, Ni, Co, Cu, Ti, V, Cr, Fe, Zr, Nb, Ru, Os, Ir, Rh, Mo, Pd, Hf, Ta or W.

[0015] The selection of the metal substrate in the present application has certain universality, and the metal substrate has good ductility and flexibility compared with other substrates (such as silicon wafer, sapphire, quartz, etc.), which improves the application field of gallium oxide nanostructures.

[0016] Preferably, the shape of the metal substrate comprises any one of a metal sheet, a metal foil, a metal wire, a foamed metal, or a metal mesh.

[0017] Preferably, the metal substrate in step (1) is pre-treated by washing.

[0018] Preferably, the washing treatment comprises sequentially performing ultrapure water washing, acetone washing, and ethanol washing.

[0019] Preferably, the temperature of the one-step heat treatment in step (1) is 80-300℃, for example, 80℃, 100℃, 150℃, 200℃, or 180℃, etc.

[0020] Preferably, the time of the one-step heat treatment in step (1) is 0.5-5h, for example, 0.5h, 1h, 2h, 2.5h, 3h, 4h, or 5h, etc.

[0021] Preferably, the catalyst in step (2) comprises any one or a combination of at least two of gallium, gold, platinum, silver, or nickel.

[0022] Preferably, the atmosphere of the coating and two-step heat treatment in step (2) comprises any one of an inert gas, air, or oxygen.

[0023] Preferably, the inert gas comprises argon or nitrogen.

[0024] Preferably, the temperature of the two-step heat treatment in step (2) is 500-750℃, for example, 500℃, 550℃, 650℃, 700℃, or 750℃, etc.

[0025] Preferably, the time of the two-step heat treatment in step (2) is 20-120min, for example, 20min, 30min, 40min, 50min, or 60min, etc.

[0026] As a preferred scheme of the present application, the method comprises the following steps:

[0027] (1) coating molten gallium on the surface of a metal substrate, and performing one-step heat treatment at 80-300℃ for 0.5h-5h to form a solid alloy phase;

[0028] (2) performing two-step heat treatment at 500-750℃ for 20-120min on the surface of the solid alloy phase under the action of a catalyst to obtain the gallium oxide nanostructure on the surface of the metal substrate.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] (1) The in-situ prepared gallium oxide nanostructure can quickly construct Ga2O3 nanostructure / metal heterostructure, and the gallium oxide nanostructure can be uniformly distributed on the metal surface. The gallium oxide nanostructure has the advantages of high specific surface area and high chemical stability, and has high application value in the fields of photocatalytic environmental purification, optoelectronic devices, sensors, wide wavelength absorption and semiconductor chips.

[0031] (2) The liquid gallium is used to prepare various nanostructures, the preparation method of gallium-based compounds prepared from liquid gallium is widened, the liquid gallium and the raw material of the base material are easy to obtain, non-toxic and non-polluting, and the preparation method is an environment-friendly preparation method. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 Figure 1 is an SEM image of the Ga2O3 nanostructure prepared on the surface of an Ag foil according to the method of Example 1 of the present application.

[0033] Figure 2 Figure 2 is an enlarged SEM image of the Ga2O3 nanostructure prepared on the surface of an Ag foil according to the method of Example 1 of the present application.

[0034] Figure 3 Figure 3 is an SEM image of the Ga2O3 nanostructure prepared on the surface of an Ag foil according to the method of Example 2 of the present application.

[0035] Figure 4 Figure 4 is an enlarged SEM image of the Ga2O3 nanostructure prepared on the surface of an Ag foil according to the method of Example 2 of the present application.

[0036] Figure 5 Figure 5 is an SEM image of the Ga2O3 nanostructure prepared on the surface of an Ag foil according to the method of Example 3 of the present application.

[0037] Figure 6 Figure 6 is an enlarged SEM image of the Ga2O3 nanostructure prepared on the surface of an Ag foil according to the method of Example 3 of the present application.

[0038] Figure 7 Figure 7 is an SEM image of the Ga2O3 nanostructure prepared on the surface of a Cu sheet according to the method of Example 4 of the present application.

[0039] Figure 8 Figure 8 is an enlarged SEM image of the Ga2O3 nanostructure prepared on the surface of a Cu sheet according to the method of Example 4 of the present application.

[0040] Figure 9 Figure 9 is an SEM image of the Ga2O3 nanostructure prepared on the surface of a Ni sheet according to the method of Example 5 of the present application.

[0041] Figure 10SEM image of Ga2O3 nanostructure prepared in-situ on the surface of Ni sheet by the method described in Example 5 of the present application. DETAILED DESCRIPTION

[0042] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations on the present application.

[0043] Example 1

[0044] The present embodiment provides a method for preparing gallium oxide nanostructure in-situ on a metal substrate, which specifically comprises the following steps:

[0045] (1) After melting bulk gallium, Ag foil is cleaned with ultrapure water, acetone and ethanol respectively, and the melted gallium is uniformly coated on the surface of the Ag foil. The treated Ag foil containing Ga is annealed at 122℃ for 3h to perform alloying. In the one-step heat treatment process, the atoms in the metal foil can dissolve and diffuse into gallium to form a solid alloy phase;

[0046] (2) Au is coated on the surface of the solid alloy phase in an Ar gas atmosphere, and two-step heat treatment is performed at 550℃ in a tube furnace for 30min to obtain Ga2O3 nanostructure on the Ag foil. The SEM image of Ga2O3 nanostructure prepared in-situ on the surface of Ag foil is shown in Figures 1-2 .

[0047] Example 2

[0048] The present embodiment provides a method for preparing gallium oxide nanostructure in-situ on a metal substrate, which specifically comprises the following steps:

[0049] (1) After melting bulk gallium, Ag foil is cleaned with ultrapure water, acetone and ethanol respectively, and the melted gallium is uniformly coated on the surface of the Ag foil. The treated Ag foil containing Ga is annealed at 122℃ for 3h to perform alloying. In the one-step heat treatment process, the atoms in the metal foil can dissolve and diffuse into gallium to form a solid alloy phase;

[0050] (2) Au is coated on the surface of the solid alloy phase in an Ar gas atmosphere, and two-step heat treatment is performed at 550℃ in a tube furnace for 30min to obtain Ga2O3 nanostructure on the Ag foil. The SEM image of Ga2O3 nanostructure prepared in-situ on the surface of Ag foil is shown in Figures 3-4 .

[0051] Example 3

[0052] The present embodiment provides a method for preparing gallium oxide nanostructure in-situ on a metal substrate, which specifically comprises the following steps:

[0053] (1) First, after melting bulk gallium, Ag foil is cleaned with ultrapure water, acetone and ethanol respectively, and the melted gallium is uniformly coated on the surface of the Ag foil. The treated Ag foil containing Ga is annealed at 120°C for 3.2h to perform alloying. In the one-step heat treatment process, atoms in the metal foil can dissolve and diffuse into gallium to form a solid alloy phase;

[0054] (2) Au is coated on the surface of the solid alloy phase in an Ar gas atmosphere, and two-step heat treatment is performed at 750°C in a tube furnace for 32min to obtain Ga2O3 nanostructures on the Ag foil. The SEM image of the Ga2O3 nanostructures prepared in situ on the surface of the Ag foil is shown in Figures 5-6 .

[0055] Example 4

[0056] The embodiment provides a method for preparing gallium oxide nanostructures in situ on a metal substrate, which specifically comprises the following steps:

[0057] (1) First, after melting bulk gallium, Cu sheet is cleaned with ultrapure water, acetone and ethanol respectively, and the melted gallium is uniformly coated on the surface of the Cu sheet. The treated Cu sheet containing Ga is annealed at 120°C for 2h to perform alloying. In the one-step heat treatment process, atoms in the metal foil can dissolve and diffuse into gallium to form a solid alloy phase;

[0058] (2) Au is coated on the surface of the solid alloy phase in an Ar gas atmosphere, and two-step heat treatment is performed at 750°C in a tube furnace for 30min to obtain Ga2O3 nanostructures on the Cu sheet. The SEM image of the Ga2O3 nanostructures prepared in situ on the surface of the Cu sheet is shown in Figures 7-8 .

[0059] Example 5

[0060] The embodiment provides a method for preparing gallium oxide nanostructures in situ on a metal substrate, which specifically comprises the following steps:

[0061] (1) First, after melting bulk gallium, Ni sheet is cleaned with ultrapure water, acetone and ethanol respectively, and the melted gallium is uniformly coated on the surface of the Ni sheet. The treated Ni sheet containing Ga is annealed at 180°C for 5h to perform alloying. In the one-step heat treatment process, atoms in the metal foil can dissolve and diffuse into gallium to form a solid alloy phase;

[0062] (2) Au was coated on the surface of the solid alloy phase in an Ar atmosphere, and two-step heat treatment was carried out at 750°C for 30 min in a tube furnace to obtain Ga2O3 nanostructures on a Ni sheet. The SEM image of the Ga2O3 nanostructures prepared in situ on the surface of the Ni sheet is shown in FIG. 2. Figures 9-10

[0063] The applicant declares that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily conceived by any person skilled in the art, and all such changes or replacements fall within the protection scope and disclosure scope of the present application.​

Claims

1. A method for in-situ preparation of gallium oxide nanostructures on a metal substrate, characterized in that, The method comprises the following steps: (1) coating molten gallium on the surface of a metal substrate, and performing one-step heat treatment to form a solid alloy phase; (2) under the action of a catalyst, the surface of the solid alloy phase is subjected to two-step heat treatment to obtain the gallium oxide nanostructure on the surface of the metal substrate; In step (1), the material of the metal substrate comprises any one or a combination of at least two of Au, Pt, Ag, Ni, Co, Cu, Ti, V, Cr, Fe, Zr, Nb, Ru, Os, Ir, Rh, Mo, Pd, Hf, Ta or W, the temperature of the one-step heat treatment is 80-300°C, and the time of the one-step heat treatment is 0.5-5h; In step (2), the temperature of the two-step heat treatment is 500-750°C, and the time of the two-step heat treatment is 20-120min.

2. The method of claim 1, wherein, The shape of the metal substrate comprises any one of a metal sheet, a metal foil, a metal wire, a foamed metal or a metal mesh.

3. The method of claim 1, wherein, In step (1), the metal substrate is subjected to a washing treatment in advance.

4. The method of claim 3, wherein, The washing treatment comprises sequentially performing ultrapure water washing, acetone washing and ethanol washing.

5. The method of claim 1, wherein, In step (2), the catalyst comprises any one or a combination of at least two of gallium, gold, platinum, silver or nickel.

6. The method of claim 1, wherein, In step (2), the atmosphere for the coating and the two-step heat treatment comprises any one of an inert gas, air or oxygen.

7. The method of claim 6, wherein, The inert gas comprises argon or nitrogen.

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