Preparation method of gamma phase gallium oxide nanosheet, gamma phase gallium oxide nanosheet and application thereof

Abstract

This invention discloses a method for preparing γ-phase gallium oxide nanosheets, the γ-phase gallium oxide nanosheets themselves, and their applications. The method for preparing γ-phase gallium oxide nanosheets includes the following steps: diluting and evaporating an acidic solution of Ga(NO3)3 to obtain a precursor crystal; mixing the precursor crystal, an organic solvent, and water to dissolve the crystal, obtaining a precursor solution; adding a precipitant to the precursor solution and adjusting the pH to 10.0-11.0 to obtain a suspension; transferring the suspension to a hydrothermal reactor and storing it at 160℃-300℃ for 6-9 hours, followed by solid-liquid separation, washing, and drying to obtain γ-phase gallium oxide nanosheets. This invention can obtain γ-Ga2O3 nanosheets and can effectively improve the yield and size uniformity of γ-Ga2O3 nanosheets.

Description

Technical Field

[0001] This invention relates to the field of gallium oxide nanotechnology, and more specifically, to a method for preparing γ-phase gallium oxide nanosheets, γ-phase gallium oxide nanosheets, and their applications. Background Technology

[0002] Gallium oxide (Ga₂O₃), a highly anticipated fourth-generation semiconductor material, exhibits immense application potential in semiconductor power devices, photodetectors, and energy storage due to its wide bandgap (approximately 4.85 eV) and high theoretical breakdown field (8 MV / m). Ga₂O₃ possesses five distinct crystal phases: α, β, γ, ε, and δ. Among these, the metastable γ-Ga₂O₃, with its wide bandgap, unique luminescence properties, and surface acidity / alkalinity, has become a focal point for research in photonics, solar energy devices, and catalysis applications. Furthermore, the defective spinel structure of γ-Ga₂O₃ provides a large specific surface area and a high number of surface atoms. Moreover, compared to one-dimensional nanorod structures, two-dimensional nanosheet structures offer better specific surface area, surface activity, and dispersion performance in target products, which is beneficial for promoting surface reactions, thus demonstrating higher performance and application potential in sensing, energy storage, and conversion.

[0003] Although various methods for preparing γ-Ga₂O₃ have been developed, including solvothermal, hydrothermal, and physical evaporation methods, these methods still have limitations in precisely controlling the morphology and size of two-dimensional nanosheets. Existing preparation processes often involve complex steps and high costs, and are difficult to scale up to produce high-quality nanomaterials that meet application requirements. Therefore, developing an efficient, low-cost method for the mass production of two-dimensional nanosheets is not only an important research direction in materials science, but also crucial for realizing the application of γ-Ga₂O₃ materials in high-performance semiconductors, optoelectronic devices, and catalysts.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing γ-phase gallium oxide nanosheets, γ-phase gallium oxide nanosheets and their applications, thereby obtaining a method for efficient, low-cost, and convenient mass production of two-dimensional nanosheets.

[0006] This invention is implemented as follows:

[0007] In a first aspect, the present invention provides a method for preparing γ-phase gallium oxide nanosheets, comprising the following steps:

[0008] The precursor crystals were obtained by diluting and evaporating the acid solution of Ga(NO3)3.

[0009] The precursor crystal, organic solvent, and water are mixed to dissolve the crystal, yielding a precursor solution.

[0010] A precipitant was added to the precursor solution and the pH was adjusted to 10.0-11.0 to obtain a suspension;

[0011] The suspension was transferred to a hydrothermal reactor and stored at 160℃-300℃ for 6-9 hours. After solid-liquid separation, washing, and drying, γ-phase gallium oxide nanosheets were obtained.

[0012] In an optional embodiment, the acid solution of Ga(NO3)3 is obtained by dissolving Ga(NO3)3·xH2O in acid, where x is a positive integer, and the acid is at least one of concentrated hydrochloric acid and concentrated sulfuric acid;

[0013] Preferably, the concentration of the acid is 36wt%-38wt%;

[0014] Preferably, the acid is concentrated hydrochloric acid;

[0015] Preferably, the purity of the Ga(NO3)3·xH2O is greater than 99.9 wt%;

[0016] Preferably, the mass fraction of Ga(NO3)3 in the acid solution of Ga(NO3)3 is 20wt%-30wt%.

[0017] In an optional embodiment, the acid solution of Ga(NO3)3 is repeatedly diluted and evaporated to crystallize more than three times to obtain the precursor crystal.

[0018] In an optional embodiment, the volume ratio of water added during dilution to the volume of acid is (3.5-7.5):1;

[0019] Preferably, the evaporation and crystallization temperature is 60℃-80℃, and evaporation ends when the water content of the solution is less than 3wt%.

[0020] In an optional embodiment, the organic solvent is at least one selected from ethylenediamine, isopropanol, and ethylene glycol;

[0021] Preferably, the concentration of the precursor in the precursor solution is 0.05-0.5 mol / L;

[0022] Preferably, the volume ratio of the reducing agent to water is 2:(3-8);

[0023] Preferably, the crystals are continuously stirred for 3-6 hours after dissolution.

[0024] In an optional embodiment, the precipitant is at least one of ammonia, sodium hydroxide, or potassium hydroxide.

[0025] In an optional embodiment, the washing solution in the washing step is deionized water and alcohol;

[0026] Preferably, the washing step is performed three times, and the washing solutions for the three washes are deionized water, ethanol and isopropanol in sequence.

[0027] In an optional embodiment, the drying is performed using vacuum drying at a temperature of 80℃-120℃ for 10h-14h.

[0028] Secondly, the present invention provides a γ-phase gallium oxide nanosheet, which is prepared by any one of the preparation methods described in the foregoing embodiments.

[0029] Thirdly, the present invention provides an application of the γ-phase gallium oxide nanosheets described in the foregoing embodiments in semiconductor power devices, photodetectors, energy storage, or catalysts.

[0030] The present invention has the following beneficial effects:

[0031] (1) The present invention simplifies the preparation process and significantly reduces production costs by using common and inexpensive chemical reagents.

[0032] (2) The technical solution adopted in this invention can effectively improve the yield and size uniformity of the prepared γ-Ga2O3 nanosheets, ensuring high-quality products.

[0033] (3) The method of the present invention can obtain γ-Ga2O3 nanosheets by controlling the reaction conditions, providing optimized materials for specific application fields.

[0034] (4) The method of the present invention simplifies the traditional synthesis process. By controlling the reaction conditions, it can directly obtain nanosheets with high specific surface area and γ-Ga2O3 without surfactants. It is suitable for large-scale production and has good industrialization potential. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a flowchart of Embodiment 1 of the present invention;

[0037] Figure 2 The XRD pattern of the product obtained in Example 1 of this invention;

[0038] Figure 3 This is a TEM image of the product obtained in Example 1 of this invention;

[0039] Figure 4 This is the SAED diagram of the product obtained in Example 1 of the present invention;

[0040] Figure 5 This is the SEM image of the product obtained in Example 4 of this invention;

[0041] Figure 6 This is a TEM image of the product obtained in Example 5 of the present invention;

[0042] Figure 7 This is a TEM image of the product obtained in Example 6 of the present invention;

[0043] Figure 8 This is the SEM image of the product obtained in Comparative Example 1 of this invention;

[0044] Figure 9 This is a TEM image of the product obtained in Comparative Example 2 of this invention;

[0045] Figure 10 This is a TEM image of the product obtained in Comparative Example 3 of this invention;

[0046] Figure 11 This is a TEM image of the product obtained in Comparative Example 4 of this invention;

[0047] Figure 12 This is a TEM image of the product obtained in Comparative Example 5 of this invention;

[0048] Figure 13 This is the SEM image of the product obtained in Comparative Example 6 of this invention;

[0049] Figure 14 The XRD pattern of the product obtained in Comparative Example 10 of this invention;

[0050] Figure 15 This is a TEM image of the product obtained in Comparative Example 11 of this invention. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0052] This invention provides a method for preparing γ-phase gallium oxide nanosheets, specifically including the following steps:

[0053] S1. Dissolve Ga(NO3)3·xH2O with a purity greater than 99.9 wt% in acid to obtain an acid solution with a Ga(NO3)3 mass fraction of 20 wt%-30 wt%, where x is a positive integer, usually 3, 5, or 9. The acid is at least one of concentrated hydrochloric acid and concentrated sulfuric acid, and the concentration of the acid is 36 wt%-38 wt%. In this step, strong acidic concentrated sulfuric acid or concentrated hydrochloric acid is used to dissolve gallium nitrate, while simultaneously inhibiting the hydrolysis of gallium nitrate to generate oxyacid anions GaO3. 3- GaO2 - Promote Ga 3+ The release of [gallium] provides a high concentration of active gallium source for subsequent reactions.

[0054] S2. The acid solution of Ga(NO3)3 is repeatedly diluted and evaporated for crystallization more than three times to obtain precursor crystals. During dilution, the volume ratio of water added to the acid in step S1 is (3.5-7.5):1. The evaporation crystallization temperature is 60℃-80℃, and evaporation ends when the water content of the solution is less than 3wt%. Then, dilution and evaporation crystallization are repeated three times or more. Repeated evaporation and dissolution improve the uniformity and yield of the precursor crystals, laying the foundation for preparing γ-Ga2O3 nanosheets with high yield and high specific surface area.

[0055] S3. The precursor crystal, organic solvent, and water are mixed to dissolve the crystal, and then stirred continuously for 3-6 hours to obtain a precursor solution. The organic solvent is at least one of ethylenediamine, isopropanol, and ethylene glycol; the concentration of the precursor in the precursor solution is 0.05-0.5 mol / L; and the volume ratio of the organic solvent to water is 2:(3-8). Appropriate selection of the organic solvent can suppress the formation of the intermediate product GaOOH. Furthermore, γ-Ga2O3 may also undergo hydrolysis and condensation to produce GaOOH under certain conditions. Therefore, the selection of suitable organic solvents and reaction conditions lays the foundation for preparing γ-Ga2O3 nanosheets with high yield and high specific surface area.

[0056] S3. Add a precipitant to the precursor solution and adjust the pH to 10.0-11.0 to obtain a suspension. The precipitant is at least one of ammonia, sodium hydroxide, and potassium hydroxide. The precipitant is added dropwise to the solution to eventually form a gel-like suspension.

[0057] S4. The suspension is transferred to a hydrothermal reactor and stored at 160℃-300℃ for 6-9 hours, followed by solid-liquid separation, washing, and drying to obtain γ-phase gallium oxide nanosheets. The washing solution in the washing step is deionized water and alcohol. Preferably, the washing step is performed three times, with the washing solutions for the three washes being deionized water, ethanol, and isopropanol, respectively. The drying is performed under vacuum at a temperature of 80℃-120℃ for 10-14 hours.

[0058] The following reaction may occur in this invention to prepare gallium oxide.

[0059] Ga 3+ +3OH - →GaOOH+H2O

[0060] 2GaOOH→Ga2O3+H2O

[0061] Ga 3+ +3OH - →Ga(OH)3↓

[0062] 2Ga(OH)3→Ga2O3+3H2O

[0063] The γ-Ga2O3 nanosheets prepared by this invention, due to their unique physicochemical properties, are applicable to multiple cutting-edge technology fields, including but not limited to:

[0064] Semiconductor power devices: The wide bandgap of γ-Ga2O3 makes it an ideal semiconductor material for manufacturing high-efficiency, high-voltage power devices such as transistors and diodes. These devices are widely used in power transmission, electric vehicles and renewable energy systems.

[0065] Photodetectors: Due to their excellent photoelectric properties, γ-Ga2O3 nanosheets exhibit remarkable performance, especially in the field of ultraviolet light detection. They can be used to develop high-sensitivity, fast-response ultraviolet light detectors, suitable for environmental monitoring, flame detection, and biological detection.

[0066] In the field of energy storage: The large specific surface area and special electrochemical properties of γ-Ga2O3 nanosheets make them an ideal electrode material for energy storage devices such as supercapacitors and lithium-ion batteries, which is expected to improve the energy density and cycle stability of energy storage devices.

[0067] Catalysts: γ-Ga2O3 nanosheets also show potential in the field of catalysts. The high density of their surface active sites helps to improve catalytic efficiency and can be used for environmental purification (such as air purification and water treatment) and chemical synthesis (such as the catalysis of organic reactions).

[0068] Photocatalysis and photoelectrochemical water splitting: The wide bandgap properties of γ-Ga2O3 nanosheets make them effective photocatalysts for the photocatalytic splitting of water to produce hydrogen, providing an efficient pathway for the development of clean energy.

[0069] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0070] Example 1

[0071] This embodiment provides a method for preparing γ-phase gallium oxide nanosheets, such as... Figure 1 As shown, the specific steps include:

[0072] S1. At 25℃, Ga(NO3)3·xH2O with a purity of 99.9wt% was dissolved in 3.5 ml of 37wt% hydrochloric acid to obtain an acidic solution of Ga(NO3)3 with a mass fraction of 25wt%, where x is 3, 5, and 9.

[0073] S2. The acid solution of Ga(NO3)3 was repeatedly diluted and evaporated to crystallize three times to obtain the precursor crystals. 10 ml of water was added each time it was diluted, and the temperature of evaporation and crystallization was 70℃ each time until the liquid was completely evaporated.

[0074] S3. The precursor crystal, ethylene glycol and water are mixed to dissolve the crystal and then stirred continuously for 3 hours to obtain a precursor solution. The concentration of the precursor in the precursor solution is 0.2 mol / L; the volume ratio of ethylene glycol to water is 2:8.

[0075] S4. Add 1 mol / L potassium hydroxide to the precursor solution until the pH value is 10.5 to obtain a suspension.

[0076] S5. After storing the suspension at 210°C for 6 hours, cool it to below 50°C and remove it to obtain a milky white suspension. Then, wash the milky white suspension three times with deionized water, ethanol and isopropanol in sequence. After each wash, perform solid-liquid separation at a rate of 9000 r / min to obtain a white precipitate. Store it in a vacuum drying oven at 120°C for 12 hours to obtain γ-phase gallium oxide nanosheets.

[0077] X-ray diffraction, transmission electron microscopy, and electron diffraction tests were performed on the γ-phase gallium oxide nanosheets obtained in this embodiment. The results are shown in [reference needed]. Figure 2 , Figure 3 and Figure 4 , Figure 2 In the XRD pattern of γ-Ga2O3 nanosheets, the main peaks correspond to the γ phase of Ga2O3 material, which indicates that the material is γ-Ga2O3 powder material. Figure 3In the TEM image of γ-Ga2O3 nanosheets, plate-like primary crystals can be observed to aggregate into independent nanosheets, with a maximum size of approximately 80 nm. Figure 4 The SAED pattern of the γ-Ga₂O₃ nanosheets shows that the four distinct rings in the diffraction pattern correspond to the four diffraction families of the γ-Ga₂O₃ lattice plane, further confirming that the prepared material is indeed γ-Ga₂O₃ nanosheets. The final mass of the obtained γ-Ga₂O₃ nanosheets was 364.38 mg, with a calculated yield of 97.2%. Using nitrogen as the adsorbate, the specific surface area of ​​the prepared γ-Ga₂O₃ nanosheets was calculated to be 268.3 m². 2 ·g -1 .

[0078] Example 2

[0079] This embodiment provides a method for preparing γ-phase gallium oxide nanosheets, specifically including the following steps:

[0080] S1. At 25℃, Ga(NO3)3·xH2O with a purity of 99.9wt% is dissolved in 2ml of 37wt% hydrochloric acid to obtain an acidic solution of Ga(NO3)3 with a mass fraction of 30wt%, where x is 3, 5 and 9.

[0081] S2. The acid solution of Ga(NO3)3 was repeatedly diluted and evaporated to crystallize three times to obtain the precursor crystals. 15 ml of water was added each time it was diluted, and the temperature of evaporation and crystallization was 80℃ each time until the liquid was completely evaporated.

[0082] S3. The precursor crystal, isopropanol and water are mixed to dissolve the crystal, and then stirred continuously for 6 hours to obtain a precursor solution. The concentration of the precursor in the precursor solution is 0.2 mol / L; the volume ratio of ethylene glycol to water is 2:3.

[0083] S3. Add 1 mol / L potassium hydroxide to the precursor solution until the pH value is 11 to obtain a suspension.

[0084] S4. The suspension was transferred to a stainless steel autoclave lined with polytetrafluoroethylene (PTFE) and stored at 195°C for 3 hours. After cooling to below 50°C, the suspension was removed, yielding a milky white suspension. This milky white suspension was then washed three times sequentially with deionized water, ethanol, and isopropanol. After each wash, solid-liquid separation was performed at a rate of 9000 r / min to obtain a white precipitate. This precipitate was then stored in a vacuum drying oven at 120°C for 12 hours to obtain γ-phase gallium oxide nanosheets. The final mass of γ-Ga₂O₃ nanosheets obtained was 240.78 mg, with a calculated yield of 92.8%. Using nitrogen as the adsorbate, the specific surface area of ​​the prepared γ-Ga₂O₃ nanosheets was calculated to be 249.5 m². 2 ·g -1.

[0085] Example 3

[0086] This embodiment provides a method for preparing γ-phase gallium oxide nanosheets, specifically including the following steps:

[0087] S1. At 25℃, Ga(NO3)3·xH2O with a purity of 99.9wt% was dissolved in 4.5 ml of 37wt% hydrochloric acid to obtain an acidic solution of Ga(NO3)3 with a mass fraction of 20wt%.

[0088] S2. The acid solution of Ga(NO3)3 was repeatedly diluted and evaporated to crystallize three times to obtain the precursor crystals. 15 ml of water was added each time it was diluted, and the temperature of evaporation and crystallization was 80℃ each time until the liquid was completely evaporated.

[0089] S3. The precursor crystal, ethylene glycol and water are mixed to dissolve the crystal and then stirred continuously for 6 hours to obtain a precursor solution. The concentration of the precursor in the precursor solution is 0.2 mol / L; the volume ratio of ethylene glycol to water is 2:5.

[0090] S3. Add 1 mol / L potassium hydroxide to the precursor solution until the pH value is 11 to obtain a suspension.

[0091] S4. The suspension was transferred to a stainless steel autoclave lined with polytetrafluoroethylene (PTFE) and stored at 200°C for 4 hours. After cooling to below 50°C, the suspension was removed, yielding a milky white suspension. This milky white suspension was then washed three times sequentially with deionized water, ethanol, and isopropanol. After each wash, solid-liquid separation was performed at a rate of 9000 r / min to obtain a white precipitate. This precipitate was then stored in a vacuum drying oven at 120°C for 12 hours to obtain γ-phase gallium oxide nanosheets. The final mass of γ-Ga₂O₃ nanosheets obtained was 368.17 mg, with a calculated yield of 94.6%. Using nitrogen as the adsorbate, the specific surface area of ​​the prepared γ-Ga₂O₃ nanosheets was calculated to be 256.7 m². 2 ·g -1 .

[0092] Example 4

[0093] The only difference between this embodiment and Embodiment 1 is that the hydrochloric acid in step S1 is replaced with sulfuric acid of equal mass and concentration.

[0094] This embodiment provides a method for preparing γ-phase gallium oxide nanosheets, specifically including the following steps:

[0095] S1. At 25℃, Ga(NO3)3·xH2O with a purity of 99.9wt% was dissolved in 3.5 ml of 37wt% sulfuric acid to obtain an acidic solution of Ga(NO3)3 with a mass fraction of 25wt%.

[0096] S2, same as Example 1.

[0097] S3, same as Example 1.

[0098] S4, Same as Example 1.

[0099] S5, same as Example 1.

[0100] Figure 5 Scanning electron microscope (SEM) images of the product obtained in this embodiment are shown. It can be seen that the prepared product has irregular shapes, including flakes and granules, and exhibits significant agglomeration. The final product mass is 393.21 mg, with a calculated yield of 95.8%. Using nitrogen as the adsorbate, the calculated specific surface area of ​​the prepared product is 82.5 m². 2 ·g -1 The lower specific surface area may be due to aggregation.

[0101] Example 5

[0102] The only difference between this embodiment and Embodiment 1 is that, in step S2, the acid solution of Ga(NO3)3 is repeatedly diluted and evaporated for crystallization five times.

[0103] Figure 6 Transmission electron microscopy (TEM) images of the product obtained in this embodiment are shown. It can be seen that the morphology and size are not significantly different from the product obtained in Example 1, indicating that the number of evaporation and crystallization cycles may only affect the final yield. The final product mass was 367.01 mg, and the calculated yield was 97.9%. Using nitrogen as the adsorbate, the specific surface area of ​​the prepared product was calculated to be 265.8 m². 2 ·g -1 .

[0104] Example 6

[0105] The only difference between this embodiment and Embodiment 1 is that, in step S2, 25 ml of water is added each time the product is diluted.

[0106] Figure 7 Transmission electron microscopy (TEM) images of the product obtained in this embodiment are shown. It can be seen that the morphology is not significantly different from that of the product obtained in Example 1, but the number of small nanosheets has increased. The final product mass was 362.88 mg, with a calculated yield of 96.8%. Using nitrogen as the adsorbate, the specific surface area of ​​the prepared product was calculated to be 266.2 m².2 ·g -1 .

[0107] Comparative Example 1

[0108] This embodiment provides a method for preparing gallium oxide, specifically including the following steps:

[0109] S1. At 25°C, Ga(NO3)3·xH2O with a purity of 99.9 wt% was dissolved in 3.5 ml of deionized water, and surfactant P123 was added to it to obtain a Ga(NO3)3 solution with a mass fraction of 25 wt% Ga(NO3)3 and a mass fraction of 12.5 wt% surfactant P123, where x is 3, 5 and 9.

[0110] S2. Slowly add ethylene glycol to the well-stirred Ga(NO3)3 solution, controlling the volume ratio of ethylene glycol to water to be 1:4, and the concentration of Ga in the solution to be 0.2 mol / L. Then continue stirring for 3 hours.

[0111] S3-S4 are the same as S4-S5 in Example 1.

[0112] Figure 8 Scanning electron microscope (SEM) images of the obtained product are shown, revealing that the prepared nanocrystals are approximately spherical and exhibit agglomeration. The final product mass is 300.14 mg, with a calculated yield of 93.6%. Using nitrogen as the adsorbate, the calculated specific surface area of ​​the prepared product is 50.6 m². 2 ·g -1 The lower specific surface area may be due to aggregation.

[0113] Comparative Example 2

[0114] This embodiment provides a method for preparing γ-phase gallium oxide, specifically including the following steps:

[0115] S1, Same as Example 1;

[0116] S2. Add 10 ml of deionized water to the acid solution of Ga(NO3)3 for dilution, and then place it at 70℃ to evaporate and crystallize until all the liquid has evaporated;

[0117] S3, Same as Example 1;

[0118] S4, Same as Example 1;

[0119] S5, same as Example 1.

[0120] Figure 9Transmission electron microscopy (TEM) images of the prepared γ-Ga₂O₃ are shown. The γ-Ga₂O₃ exhibits a plate-like morphology, but most of it remains in an irregular, aggregated state. The final product mass is 341.89 mg, with a calculated yield of 91.2%. Using nitrogen as the adsorbate, the specific surface area of ​​the prepared product was calculated to be 198.7 m². 2 ·g -1 The decrease in specific surface area may be due to aggregation.

[0121] Comparative Example 3

[0122] The only difference between this comparative example and Example 1 is that, in step S2, the temperature for each evaporation and crystallization is 100°C.

[0123] Figure 10 Transmission electron microscopy (TEM) images of the prepared γ-Ga₂O₃ are shown. The prepared γ-Ga₂O₃ has essentially the same shape and size as the product prepared in Example 1. The final product mass is 360.26 mg, and the calculated yield is 96.1%. Using nitrogen as the adsorbate, the specific surface area of ​​the prepared product was calculated to be 255.1 m². 2 ·g -1 .

[0124] Comparative Example 4

[0125] The only difference between this comparative example and Example 1 is that, in step S2, the temperature for each evaporation and crystallization is 50°C.

[0126] Figure 11 Transmission electron microscopy (TEM) images of the prepared γ-Ga₂O₃ are shown. It can be seen that the morphology of the prepared γ-Ga₂O₃ is basically the same as that of the product prepared in Example 1, but the size is reduced. The final product mass is 361.46 mg, and the calculated yield is 96.5%. Using nitrogen as the adsorbate, the specific surface area of ​​the prepared product is calculated to be 251.3 m². 2 ·g -1 .

[0127] Comparative Example 5

[0128] The only difference between this comparative example and Example 1 is that, in step S3, the stirring is continued for 1 hour.

[0129] Figure 12 Transmission electron microscopy (TEM) images of the prepared γ-Ga₂O₃ are shown. It can be seen that the prepared γ-Ga₂O₃ is still in nanosheet form, but the aggregation phenomenon is quite serious. The final product mass is 364.39 mg, and the calculated yield is 92.4%. Using nitrogen as the adsorbate, the specific surface area of ​​the prepared product is calculated to be 210.5 m².2 ·g -1 The lower specific surface area is likely due to aggregation.

[0130] Comparative Example 6

[0131] The only difference between this comparative example and Example 1 is that in step S4, potassium hydroxide is replaced with an equal volume and concentration of ammonia.

[0132] Figure 13 Scanning electron microscope (SEM) images of the prepared γ-Ga₂O₃ are shown. The γ-Ga₂O₃ exhibits a network-like cluster composed of smaller crystal particles with irregular boundaries. The final product yield was 265.82 mg, with a calculated yield of 95.1%. Using nitrogen as the adsorbate, the specific surface area of ​​the prepared product was calculated to be 98.5 m². 2 ·g -1 .

[0133] Comparative Example 7

[0134] The only difference between this comparative example and Example 1 is that, in step S4, 1 mol / L potassium hydroxide is added until the pH value is 9.5.

[0135] Adjusting the pH to 9.5 resulted in a more dilute suspension, leading to a decrease in the final yield of γ-Ga₂O₃, while the morphology of the final product remained unchanged. The final product mass was 263.92 mg, with a calculated yield of 70.4%. Using nitrogen as the adsorbate, the calculated specific surface area of ​​the prepared product was 238.3 m². 2 ·g -1 .

[0136] Comparative Example 8

[0137] The only difference between this comparative example and Example 1 is that, in step S4, 1 mol / L potassium hydroxide is added until the pH value is 11.5.

[0138] When the pH was adjusted to 11.5, the suspension disappeared and the solution became clear and transparent, making it impossible to obtain the product by the solvothermal method.

[0139] Comparative Example 9

[0140] The only difference between this comparative example and Example 1 is that, in step S5, the suspension is stored at 130°C for 6 hours.

[0141] If the temperature is too low, the solvothermal reaction will not proceed completely.

[0142] Comparative Example 10

[0143] The only difference between this comparative example and Example 1 is that, in step S5, the suspension is stored at 350°C for 6 hours.

[0144] Figure 14 X-ray diffraction (XRD) images of the prepared product are shown, revealing that the prepared nanopowder is GaOOH. This indicates that a transformation from γ-Ga₂O₃ to GaOOH occurred at excessively high solvothermal reaction temperatures. GaOOH should be obtained through a condensation reaction following the hydrolysis of γ-Ga₂O₃. The final product mass was 398.14 mg, with a calculated yield of 96.9%. Using nitrogen as the adsorbate, the specific surface area of ​​the prepared product was calculated to be 38.6 m². 2 ·g -1 .

[0145] Comparative Example 11

[0146] The only difference between this comparative example and Example 1 is that, in step S3, ethylene glycol is replaced with an equal mass of EDA.

[0147] Figure 15 Transmission electron microscopy (TEM) images of the prepared γ-Ga₂O₃ are shown, revealing that the product is not in the form of nanosheets but rather large clusters. The final product mass was 353.51 mg, with a calculated yield of 94.3%. Using nitrogen as the adsorbate, the calculated specific surface area of ​​the prepared product was 52.3 m². 2 ·g -1 .

[0148] The composition, yield, specific surface area and yield of the products obtained in the above embodiments and comparative examples were tested. The test results are shown in Table 1. When testing the specific surface area, the adsorbate was nitrogen.

[0149] Table 1

[0150] product Yield, % <![CDATA[Specific surface area, m 2 ·g -1 > Example 1 <![CDATA[γ-Ga2O3]]> 97.2 268.3 Example 2 <![CDATA[γ-Ga2O3]]> 92.8 249.5 Example 3 <![CDATA[γ-Ga2O3]]> 94.6 256.7 Example 4 <![CDATA[γ-Ga2O3]]> 95.8 82.5 Example 5 <![CDATA[γ-Ga2O3]]> 97.9 265.8 Example 6 <![CDATA[γ-Ga2O3]]> 96.8 266.2 Comparative Example 1 <![CDATA[γ-Ga2O3]]> 93.6 50.6 Comparative Example 2 <![CDATA[γ-Ga2O3]]> 91.2 198.7 Comparative Example 3 <![CDATA[γ-Ga2O3]]> 96.1 255.1 Comparative Example 4 <![CDATA[γ-Ga2O3]]> 96.5 251.3 Comparative Example 5 <![CDATA[γ-Ga2O3]]> 92.4 210.5 Comparative Example 6 <![CDATA[γ-Ga2O3]]> 95.1 98.5 Comparative Example 7 <![CDATA[γ-Ga2O3]]> 70.4 238.3 Comparative Example 8 / / / Comparative Example 9 / / / Comparative Example 10 GaOOH 96.9 38.6 Comparative Example 11 <![CDATA[γ-Ga2O3]]> 94.3 52.3

[0151] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing γ-phase gallium oxide nanosheets, characterized in that, Includes the following steps: The acid solution of Ga(NO3)3 was repeatedly diluted and evaporated and crystallized more than three times to obtain the precursor crystals; the evaporation and crystallization temperature was 60℃-80℃, and evaporation was stopped when the water content of the solution was less than 3wt%; The precursor crystal is mixed with an organic solvent and water to dissolve the crystal, thereby obtaining a precursor solution. The organic solvent is at least one of isopropanol and ethylene glycol. A precipitant is added to the precursor solution and the pH is adjusted to 10.0-11.0 to obtain a suspension, wherein the precipitant is at least one of sodium hydroxide or potassium hydroxide; The suspension was stored at 160℃-300℃ for 6-9 hours, followed by solid-liquid separation, washing, and drying to obtain γ-phase gallium oxide nanosheets.

2. The method for preparing γ-phase gallium oxide nanosheets according to claim 1, characterized in that, The acid solution of Ga(NO3)3 is obtained by dissolving Ga(NO3)3·xH2O in acid, where x is a positive integer, and the acid is concentrated hydrochloric acid.

3. The method for preparing γ-phase gallium oxide nanosheets according to claim 2, characterized in that, The concentration of the acid is 36wt%-38wt%.

4. The method for preparing γ-phase gallium oxide nanosheets according to claim 2, characterized in that, The purity of the Ga(NO3)3·xH2O is greater than 99.9 wt%.

5. The method for preparing γ-phase gallium oxide nanosheets according to claim 2, characterized in that, In the acid solution of Ga(NO3)3, the mass fraction of Ga(NO3)3 is 20wt%-30wt%.

6. The method for preparing γ-phase gallium oxide nanosheets according to claim 2, characterized in that, The ratio of the volume of water added during dilution to the volume of the acid is (3.5-7.5):

1.

7. The method for preparing γ-phase gallium oxide nanosheets according to claim 1, characterized in that, The concentration of the precursor in the precursor solution is 0.05-0.5 mol / L.

8. The method for preparing γ-phase gallium oxide nanosheets according to claim 1, characterized in that, The volume ratio of the organic solvent to water is 2:(3-8).

9. The method for preparing γ-phase gallium oxide nanosheets according to claim 1, characterized in that, After the crystals dissolve, continue stirring for 3-6 hours.

10. The method for preparing γ-phase gallium oxide nanosheets according to claim 1, characterized in that, The washing solution used in the washing step is deionized water and alcohol.

11. The method for preparing γ-phase gallium oxide nanosheets according to claim 10, characterized in that, The washing process is performed three times, with the washing solutions being deionized water, ethanol, and isopropanol, respectively.

12. The method for preparing γ-phase gallium oxide nanosheets according to claim 1, characterized in that, The drying process employs vacuum drying at a temperature of 80℃-120℃ for 10-14 hours.

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