A method for synthesizing metal oxide material

Abstract

The present invention discloses a method for synthesizing a metal oxide material, which belongs to the field of oxide materials. The method comprises the following steps: first, selecting metal salts corresponding to five or more metal elements, and dissolving the metal salts in a reducing substance containing a hydroxyl functional group until the metal salts are completely dissolved to form a solution; the metal elements range from Li, Na, K, Mg, Ca, Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Cd, Sn, Cs, La, Ba, Ce, Nd, W, Re, Ir, Pt, and Bi; second, adding tannic acid as a reducing agent to the solution to form a mixed solution; and third, adding a base to the mixed solution for reaction to obtain a multi-element amorphous metal oxide. The present invention can produce a multi-element amorphous metal oxide with low cost, simple and easy operation, short production cycle, and low energy consumption.

Description

Technical Field

[0001] The present invention belongs to the field of oxide materials, and in particular relates to a method for preparing or synthesizing a metal oxide material (multinary amorphous metal oxide). Background Art

[0002] As an important functional material, metal oxide materials have played an indispensable role in catalysis, energy conversion, environmental protection and other fields due to their unique physical and chemical properties. Based on advanced material design concepts, this type of material can be given more excellent performance by adjusting its composition and structure. Specifically, oxide materials with adjustable chemical order structures, by introducing a variety of metal elements, combine them in specific proportions to form a high configurational entropy system, thereby achieving precise control of material stability and functionality. This structural stability stems from the random distribution of multiple elements in the oxide lattice, which significantly increases the configurational entropy of the system, thereby improving the overall stability of the material. Compared with traditional oxide materials, oxides with adjustable chemical order structures not only have significantly improved structural complexity, but also exhibit unique advantages in electronic structure and thermodynamic properties, making them suitable for a variety of application scenarios.

[0003] In order to optimize the performance of this type of oxide material, it is necessary to start from the entropy effect and precisely control the type and proportion of metal elements by regulating the entropy of the components. The synergistic effect of different metal ions in the lattice allows the electronic structure and energy band characteristics to be flexibly adjusted, thereby improving the performance of the material in catalysis, electrochemical energy storage and other fields. In addition, the performance regulation of metal oxide materials not only depends on the entropy of the components, but also includes the control of diffusion entropy and vibration entropy. By adjusting the diffusion entropy, the material can be controlled to transform between the crystalline and amorphous states, thereby affecting its microstructure and system stability. For example, in the amorphous structure, short-range order and long-range disorder coexist, which makes the material have higher structural relaxation and adaptability, thereby exhibiting more stable and flexible physical and chemical properties.

[0004] Although this type of oxide material has shown great application potential, its synthesis still faces many challenges. Traditional solid-phase and liquid-phase synthesis methods are relatively complex and often require strict experimental conditions, which makes it difficult to control the uniformity and consistency of the material. In addition, the interactions between atoms in multi-component systems are complex, and the regulation of enthalpy and entropy is relatively difficult. Especially in the process of transformation between crystalline and amorphous states, how to effectively control diffusion entropy and vibration entropy remains a difficult problem in the synthesis of multi-component amorphous metal oxide materials. Therefore, it is particularly important to develop a new method that is simple in process, low in cost, and can be used to prepare such metal oxides in batches. This method can reduce production costs, improve production efficiency, and help realize the large-scale application of materials in industry, providing new opportunities for further promoting the development of materials science and technology. Summary of the Invention

[0005] In view of this, the present invention provides a method for synthesizing metal oxide materials, which can produce multi-component amorphous metal oxides, has low cost, simple and easy operation, short production cycle, low energy consumption, and certain adjustability.

[0006] The present invention provides a method for synthesizing a metal oxide material, comprising the following steps:

[0007] Step 1: Select metal salts corresponding to five or more metal elements, dissolve all of the metal salts in a reducing substance containing an ethanol group, and stir until the metal salts are completely dissolved to form a solution; the metal elements range from Li, Na, K, Mg, Ca, Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Cd, Sn, Cs, La, Ba, Ce, Nd, W, Re, Ir, Pt and Bi;

[0008] Step 2: adding tannic acid as a reducing agent to the solution and continuously stirring to form a mixed solution;

[0009] Step three, adding a base to the mixed solution for reaction, wherein the base is sodium hydroxide and / or potassium hydroxide, and separating to obtain a multi-element amorphous metal oxide.

[0010] The basic principles of the embodiments of the present invention include: in the present invention, tannic acid is selected as a reducing agent, which forms a strong reducing environment together with alcohols or their derivatives that also have reducing properties, which can overcome the differences in electron density between some metal ions and simultaneously reduce a variety of different metal ions to dispersed monomers. When the metal salt precursor enters the solution, its relatively stable state is destroyed. Since the concentrations of various element monomers are almost uniform, the metal elements are eventually randomly distributed. At the same time, the reaction can occur in a very short time. In the process of limited atomic monomer diffusion and rapid nucleation, due to the different distributions of different monomers and differences in diffusion kinetics, it is difficult to form long-range order. The system energy is eventually in a metastable state, realizing the non-equilibrium synthesis of metal oxides.

[0011] In a specific embodiment of the present invention, a plurality of metal salts can be weighed, dissolved in a reducing substance containing a hydroxyl functional group, and stirred for 2-60 minutes until the metal salts are completely uniform, thereby obtaining a stable solution containing the metal salts.

[0012] In step 1, the metal salt is one or more of a metal hydrochloride (chloride), nitrate, nitrite, sulfate, and acetylacetonate; specifically, chloride, nitrate, or acetylacetonate (e.g., Pd(acac)2), some of which are hydrates. Preferably, the concentration of each metal in the ethanol or its derivative is 4 g / L.-1 .

[0013] The metal elements are composed of five or more elements selected from lithium (Li), sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), strontium (Sr), zirconium (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), cadmium (Cd), tin (Sn), cesium (Cs), lanthanum (La), barium (Ba), cerium (Ce), neodymium (Nd), tungsten (W), rhenium (Re), iridium (Ir), platinum (Pt), and bismuth (Bi); the types and proportions of the elements can be adjusted arbitrarily, and specifically can be equal in mass. Furthermore, the metal elements are at least five of Mg, Ca, Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Cd, Sn, Cs, La, Ba, Ce, Nd, W, Re, Ir and Pt.

[0014] In some embodiments, the metal elements include: Mg, Al, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Cd, Sn, Ba, Ce, W, Ir, and Pt (a total of 24 elements); or, the metal elements include: Mg, Al, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Ru, Cd, Ce, and Ir (a total of 16 elements). In other embodiments, the metal elements include Cr, Fe, Co, Ni, and Cu, or include Mn, Fe, Co, Ni, and Cu.

[0015] In the step 1, the reducing substance containing a hydroxyl functional group is a solvent, preferably one of ethylene glycol, ethanol, ethanolamine, β-mercaptoethanol and diethylene glycol, further ethylene glycol or diethylene glycol.

[0016] The second step of the embodiment of the present invention is to add tannic acid to the aforementioned solution and continue stirring to keep the mixed solution uniform. Tannic acid, also known as tannic acid, tannin, etc., is a polyphenol substance widely distributed in plants; in the embodiment of the present invention, it is C 76 H 52 O 46 (reagent grade, 98%).

[0017] In step 2, the concentration of tannic acid in the mixed solution is 0.1-5 g / L; after adding tannic acid, the concentration of tannic acid in the solution can be 0.5-3 g·L -1 , specifically 2g / L.

[0018] After obtaining the mixed solution, in a specific embodiment of the present invention, an alkaline solution of sodium hydroxide / potassium hydroxide (preferably an aqueous sodium hydroxide solution) can be slowly added dropwise, and stirring can be continued for at least 5 minutes to promote the reaction. The actual reaction time in the embodiment of the present invention is very short, almost instantaneous after the addition of the alkaline solution. The stirring time is controlled to a certain extent to promote the full progress of the reaction; the reaction is carried out at room temperature. In the embodiment of the present invention, a multinary amorphous metal oxide is prepared by a liquid phase reaction. In its amorphous structure, short-range order and long-range disorder coexist.

[0019] In the step 3, it is preferred to add an alkaline solution with a concentration of 0.1-10 mol / L to the mixed solution and react under stirring conditions; the concentration of the added sodium hydroxide solution can be 0.5-2 mol / L, specifically 1 mol / L.

[0020] In the step three, after the reaction, the final product is collected by centrifugation to remove impurities in the solution; the sample is washed with water several times to ensure that no alcohol or its derivatives remain in the sample, and dried to obtain a dry multi-element amorphous metal oxide containing multiple metal elements.

[0021] In step 3, the centrifugal separation is performed at a speed of 7000-8000 rpm for 5-10 minutes, and the sample is washed with water 5-10 times. Preferably, the centrifugal separation and washing with water are performed at a speed of 8000 rpm for 5 minutes, and the sample is washed with deionized water 8 times.

[0022] In step 3, the drying step includes: placing the washed product under vacuum drying at 50-90°C to remove the remaining solvent overnight (12 hours) to obtain the sample material. The drying temperature can be 60-80°C.

[0023] Compared with the prior art, the present invention has the following technical effects: the method for synthesizing metal oxide materials in the embodiment of the present invention adopts a liquid phase co-precipitation method, which realizes the simple preparation of uniform amorphous multi-element oxides at room temperature. It is a low-cost, energy-saving, high-production-efficiency, and simple-process synthesis method; the present invention provides a new idea for the batch preparation of amorphous metal oxides. The synthesis method in the present invention covers 33 kinds of metal elements and has a certain universality; at the same time, it can also be independently selected from the elements according to application requirements, and has the characteristics of customized synthesis. The metal oxides synthesized in the present invention have the characteristics of adjustable structural order. By controlling the diffusion rate of atomic monomers in the rapid nucleation process, selective synthesis from crystalline to amorphous can be achieved.

[0024] In summary, the present invention has developed a universal synthesis strategy for a multinary amorphous metal oxide material with adjustable structural order and customizable elemental composition. The material has a nanomorphology (the material size is about 500 nm under a transmission electron microscope) and can be used as a catalyst. The method of the present invention has low cost, simple process operation, short production cycle, low energy consumption, and high efficiency, and can be customized and mass-produced. It is a synthesis strategy for metal oxide nanocatalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 XRD results of the multi-element amorphous metal oxide containing Mg, Al, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Cd, Sn, Ba, Ce, W, Ir, and Pt elements prepared in Example 1;

[0027] Figure 2 The XRD results of the multi-element amorphous metal oxide containing Mg, Al, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Ru, Cd, Ce, and Ir elements prepared in Example 2 are as follows;

[0028] Figure 3 This is a metal element distribution diagram of the multi-element amorphous metal oxide containing Mg, Al, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Ru, Cd, Ce, and Ir elements prepared in Example 2;

[0029] Figure 4 The XRD results of the multi-element amorphous metal oxide containing Cr, Fe, Co, Ni, and Cu elements in Example 3 are shown;

[0030] Figure 5 The XRD results of the multi-element amorphous metal oxide containing Mn, Fe, Co, Ni, and Cu elements in Example 4 are shown;

[0031] Figure 6 XRD results of the amorphous metal oxide containing Ru element in Comparative Example 1;

[0032] Figure 7 This is a metal element distribution diagram of the amorphous metal oxide containing Ru element in Comparative Example 1;

[0033] Figure 8 This is the XRD result of the crystalline metal oxide containing Cu element in Comparative Example 2;

[0034] Figure 9 This is the XRD result of the amorphous metal oxide containing Cu element in Comparative Example 3;

[0035] Figure 10 The XRD results of the multi-element amorphous metal oxide containing Fe, Co, Ni, Cu, and Pd elements in Example 5 are shown;

[0036] Figure 11 This is a metal element distribution diagram of the multi-component amorphous metal oxide containing Fe, Co, Ni, Cu, and Pd elements in Example 5;

[0037] Figure 12 1 is the XRD result of the amorphous metal oxide containing Co element in Comparative Example 4. DETAILED DESCRIPTION

[0038] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0039] In order to better illustrate the present invention, the following examples are provided to further illustrate the present invention. In the examples, all raw reagents and materials are commercially available, and the experimental methods without specific experimental conditions are conventional methods and conditions well known in the art.

[0040] Example 1

[0041] Weigh 0.05 g each of MgCl2·6H2O, AlCl3·6H2O, CaCl2, CrCl3·6H2O, MnCl2·4H2O, FeCl3·9H2O, CoCl2·6H2O, NiCl2·6H2O, CuCl2·2H2O, ZnCl2, SrCl2·6H2O, ZrCl4, NbCl5, MoCl5, RuCl3·H2O, RhCl3, PdCl2, CdCl2, SnCl4, BaCl2·2H2O, CeCl3·6H2O, WCl6, IrCl3·xH2O, and PtCl2, and dissolve them in 240 mL of ethylene glycol. Stir well to obtain a solution containing metal salts. Then weigh 480 mg of tannic acid and add it to the above solution. Stir well, and then add 12 mL of 1.0 mol·L -1The reaction was continued with stirring at room temperature for 60 minutes to promote sufficient reaction. The resulting solution was centrifuged at 8000 rpm for 5 minutes and washed eight times with deionized water (the same as in the following examples). The washed product was vacuum-dried at 80°C overnight to obtain a multi-element amorphous metal oxide containing Mg, Al, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Cd, Sn, Ba, Ce, W, Ir, and Pt (1.91 g of product was obtained).

[0042] Figure 1 There is no obvious diffraction peak in the X-ray diffraction (XRD) pattern, which proves the amorphous structure of the substance.

[0043] Example 2

[0044] Weigh 0.05 g each of MgCl2·6H2O, AlCl3·6H2O, CaCl2, CrCl3·6H2O, MnCl2·4H2O, FeCl3·9H2O, CoCl2·6H2O, NiCl2·6H2O, CuCl2·2H2O, ZnCl2, ZrCl4, NbCl5, RuCl3·H2O, CdCl2, CeCl3·6H2O, and IrCl3·xH2O, and dissolve them in 160 mL of ethylene glycol. Stir well to obtain a solution containing metal salts. Then weigh 320 mg of tannic acid and add it to the above solution. Stir well and then add 8 mL of 1.0 mol·L -1 The reaction was continued with stirring at room temperature for 60 minutes to promote the complete reaction. The reaction solution was centrifuged and washed several times with deionized water. The washed product was vacuum dried at 80°C overnight to obtain a multi-element amorphous metal oxide containing Mg, Al, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Ru, Cd, Ce, and Ir.

[0045] Figure 2 There is no obvious diffraction peak in the XRD diffraction pattern, which proves the amorphous structure of the substance. Figure 3 The metal element distribution diagram shows that all metal elements are evenly distributed in the sample material.

[0046] Example 3

[0047] Weigh 0.2 g each of CrCl3·6H2O, FeCl3·9H2O, CoCl2·6H2O, NiCl2·6H2O, and CuCl2·2H2O, and dissolve them in 200 mL of ethylene glycol. Stir evenly to obtain a solution containing metal salts. Then weigh 400 mg of tannic acid and add it to the above solution. Stir evenly and then add 10 mL of 1.0 mol·L -1 The reaction was continued with stirring at room temperature for 30 minutes to promote the complete reaction. The resulting solution was centrifuged and washed several times with deionized water. The washed product was then vacuum dried overnight at 80°C to obtain a multi-element amorphous metal oxide containing Cr, Fe, Co, Ni, and Cu.

[0048] Figure 4 There is no obvious diffraction peak in the XRD diffraction pattern, which proves the amorphous structure of the substance.

[0049] Example 4

[0050] Weigh 0.2 g each of MnCl2·4H2O, FeCl3·9H2O, CoCl2·6H2O, NiCl2·6H2O, and CuCl2·2H2O, and dissolve them in 200 mL of ethylene glycol. Stir evenly to obtain a solution containing metal salts. Then weigh 400 mg of tannic acid and add it to the mixed solution. Stir evenly and then add 10 mL of 1.0 mol·L -1 The reaction was continued with stirring at room temperature for 30 minutes to promote the complete reaction. The resulting solution was centrifuged and washed several times with deionized water. The washed product was then vacuum-dried at 80°C overnight to obtain a multi-element amorphous metal oxide containing Mn, Fe, Co, Ni, and Cu.

[0051] Figure 5 There is no obvious diffraction peak in the XRD diffraction pattern, which proves the amorphous structure of the substance.

[0052] Comparative Example 1

[0053] Weigh 0.2 g of RuCl3·H2O and dissolve it in 40 mL of ethylene glycol. Stir well to obtain a solution containing metal salts. Then weigh 80 mg of tannic acid and add it to the above solution. Stir well and add 2 mL of tannic acid to obtain a concentration of 1.0 mol·L -1 The reaction was continued with stirring at room temperature for 5 minutes to promote the complete reaction. The solution was centrifuged and washed several times with deionized water. Finally, the washed product was vacuum-dried at 80°C overnight to obtain an amorphous metal oxide containing Ru.

[0054] Figure 6There is no obvious diffraction peak in the XRD diffraction pattern, which proves the amorphous structure of the substance; Figure 7 The metal element distribution shows that the metal element Ru is evenly distributed in the sample material.

[0055] Comparative Example 2

[0056] Weigh 0.2 g of CuCl2·2H2O and dissolve it in 40 mL of ethylene glycol. Stir well to obtain a solution containing metal salts. Then weigh 80 mg of tannic acid and add it to the mixed solution. Stir well and add 10 mL of 1.0 mol·L -1 The reaction was continued with stirring at room temperature for 5 minutes to promote the complete reaction. The solution was centrifuged and washed several times with deionized water. The washed product was vacuum dried at 80°C overnight to obtain a crystalline metal oxide containing the Cu element.

[0057] Figure 8 The obvious diffraction peaks in the XRD diffraction pattern prove the CuO crystalline structure of the material.

[0058] Comparative Example 3

[0059] Weigh 0.2 g of Cu(NO3)2·2H2O and dissolve it in 40 mL of ethylene glycol. Stir well to obtain a solution containing metal salts. Then weigh 80 mg of tannic acid and add it to the mixed solution. Stir well and add 2 mL of 1.0 mol·L -1 The reaction was continued with stirring at room temperature for 5 minutes to promote the complete reaction. The solution was centrifuged and washed several times with deionized water. Finally, the washed product was vacuum-dried at 80°C overnight to obtain an amorphous metal oxide containing the Cu element.

[0060] Figure 9 There is no obvious diffraction peak in the XRD diffraction pattern, which proves the amorphous structure of the substance.

[0061] Example 5

[0062] Weigh 0.2 g each of Pd(acac)2, FeCl3·9H2O, CoCl2·6H2O, NiCl2·6H2O, and CuCl2·2H2O, and dissolve them in 200 mL of ethylene glycol. Stir evenly to obtain a solution containing metal salts. Then weigh 400 mg of tannic acid and add it to the above solution. Stir evenly and then add 10 mL of 1.0 mol·L -1The reaction was continued with stirring at room temperature for 30 minutes to promote the complete reaction. The solution was centrifuged and washed several times with deionized water. The washed product was vacuum dried at 80°C overnight to obtain a multi-element amorphous metal oxide containing Mn, Fe, Co, Ni, and Cu.

[0063] Figure 10 The absence of obvious diffraction peaks in the XRD diffraction pattern proves the amorphous structure of the substance. Figure 11 The metal element distribution shows that all metal elements are evenly distributed in the catalyst.

[0064] Comparative Example 4

[0065] Weigh 0.2 g of CoCl2·6H2O and dissolve it in 40 mL of diethylene glycol. Stir well to obtain a solution containing metal salts. Then weigh 80 mg of tannic acid and add it to the mixed solution. Stir well and add 2 mL of 1.0 mol·L -1 The reaction was continued with stirring at room temperature for 5 minutes to promote the complete reaction. The solution was centrifuged and washed several times with deionized water. Finally, the washed product was vacuum-dried at 80°C overnight to obtain an amorphous metal oxide containing the Co element.

[0066] Figure 12 There is no obvious diffraction peak in the XRD diffraction pattern, which proves the amorphous structure of the substance.

[0067] As can be seen from the above examples, the embodiment of the present application is a method for preparing an amorphous oxide with certain universality. The method is a liquid phase coprecipitation synthesis method, which utilizes the difference in electron density and diffusion dynamics between metal ions to quickly synthesize amorphous oxides with uniform disorder and adjustable degree, providing a new preparation process for the field of amorphous oxide synthesis. At the same time, the present invention has the advantages of energy saving, high production efficiency, simple and easy process, green and environmental protection, and no need for complex post-processing, and has the characteristics of customizability and mass production.

[0068] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0069] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for synthesizing a metal oxide material, characterized in that: The following steps are involved: Step 1: Select metal salts corresponding to five or more metal elements, dissolve all of the metal salts in a reducing substance containing a hydroxyl functional group, and stir until the metal salts are completely dissolved to form a solution; the metal elements range from at least five of Mg, Ca, Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Cd, Sn, Cs, La, Ba, Ce, Nd, W, Re, Ir, and Pt; the reducing substance is one of ethylene glycol, ethanol, ethanolamine, β-mercaptoethanol, and diethylene glycol; the five or more metal salts are of equal mass; Step 2: adding tannic acid as a reducing agent to the solution and continuously stirring to form a mixed solution; Step 3: adding 1 mol / L alkaline solution to the mixed solution for reaction, wherein the alkaline solution is sodium hydroxide solution, and separating to obtain multinary amorphous metal oxide.

2. The method for synthesizing the metal oxide material according to claim 1, wherein: In the step 1, the metal salt is one or more of metal hydrochloride, nitrate, nitrite, sulfate and acetylacetonate.

3. The method for synthesizing the metal oxide material according to claim 1, wherein: In the step 2, the concentration of tannic acid in the mixed solution is 0.1-5 g / L.

4. The method for synthesizing the metal oxide material according to any one of claims 1 to 3, characterized in that: In the step three, after the reaction, the final product is collected by centrifugation, washed with water, and dried to obtain a dry multi-component amorphous metal oxide.

5. The method for synthesizing the metal oxide material according to claim 4, wherein: In the step 3, the rotation speed of the centrifugal separation is 7000-8000 rpm, and the time is 5-10 minutes.

6. The method for synthesizing the metal oxide material according to claim 5, characterized in that: In the step 3, the centrifugal separation is followed by washing with water for 5-10 times.

7. The method for synthesizing the metal oxide material according to claim 4, wherein: In the step 3, the drying comprises: placing the product after washing with water under vacuum drying at 50-90° C. overnight.

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