Multi-layer dual-phase graphite oxide nanosheet and preparation method thereof

Abstract

The invention discloses a multilayer dual-phase graphite oxide nanosheet and a preparation method thereof. By controlling the synthesis temperature, the raw material components, the raw material ratio and the reaction time, the multilayer double-phase graphite oxide with a surface amorphous phase and a middle crystal phase is prepared. The method is simple to operate, and the prepared multi-layer dual-phase graphite oxide has good solubility in water and organic solvents and has potential application value.

Description

Technical Field

[0001] The invention relates to the field of graphene material preparation, and in particular to a method for preparing multilayer dual-phase graphite oxide. Background Art

[0002] Graphite is an allotrope of carbon, famous for its layered structure and good electrical and thermal conductivity. Graphite is widely found in nature and is often used as a lubricant, pencil lead, battery electrode material, etc. In addition, graphite has important applications in high-tech fields due to its special physical properties. However, due to the lack of hydrophilic and lipophilic groups on the surface, graphite is difficult to disperse evenly in water and organic solvents, which greatly affects its use and application in many research fields.

[0003] Graphene is a carbonaceous material with a two-dimensional periodic honeycomb lattice structure composed of six-membered carbon rings. It usually presents three states: zero-dimensional fullerene, one-dimensional carbon nanotube (CNT) and three-dimensional graphite. Since the discovery of graphene in 2004, people have conducted a lot of research on it. A single piece of graphene has the highest tensile strength (130GPa) known to date, the highest Young's modulus (1TPa), and the highest carrier mobility (15000cm 2 ·V -1 ·S -1 ) and the fastest heat transfer rate (thermal conductivity 5000W·m -1 ·K -1 ).

[0004] Graphene oxide is obtained by mechanical exfoliation after graphite is oxidized by a strong oxidant in a strong acid medium. It is an important derivative of graphene and can also be regarded as an intermediate product in the process of preparing graphene from graphite by redox method. Unlike graphene, graphene oxide contains some oxygen-containing functional groups in addition to carbon atoms, such as hydroxyl, carboxyl, epoxy, carbonyl, etc. The simultaneous presence of oxygen-containing functional groups and conjugated structures enables graphene oxide to form a stable and uniform dispersion system in water and some polar organic solvents. Due to the influence of the preparation process, there are some holes and defects in the surface of graphene oxide, which makes the mechanical properties, thermal conductivity and electrical conductivity of graphene oxide far lower than the theoretical calculated values ​​of graphene. Summary of the invention

[0005] The present invention provides a novel two-dimensional carbon material which can be uniformly dispersed in water and an organic solvent while retaining the original crystal structure and excellent physical properties of graphite, multilayer dual-phase graphite oxide and a preparation method thereof.

[0006] By controlling the reaction temperature and reaction time, the present invention retains the complete crystal structure of graphite in the middle region of the dual-phase graphite oxide, and generates a random amorphous folded structure on the surface of the sheet layer, with oxygen-containing groups such as hydroxyl and carboxyl, so that the multi-layer dual-phase graphite oxide can be stably dispersed in water and organic solvents.

[0007] The embodiments of the present invention provide the following preparation method:

[0008] 1) Slowly add 1 part of graphite powder into 50ml-200ml concentrated sulfuric acid, the size of the graphite powder is 200 mesh-500 mesh, the reaction temperature is controlled at -30℃~5℃, the reaction time is controlled at 3h-6h, and the stirring speed is controlled at 100r-500r / min;

[0009] 2) Slowly adding several portions of potassium permanganate powder to the solution prepared in step 1), the mass ratio of graphite to potassium permanganate is 1:1-1:6, the reaction temperature is controlled at -30°C to 5°C, the reaction time is controlled at 3h-6h, and the stirring speed is controlled at 100r-500r / min;

[0010] 3) Slowly add 60ml-200ml of a 10%-30% dilute sulfuric acid solution to the solution obtained in step 2) at a dropping speed of 10ml-60ml / h, the reaction temperature is controlled at -10°C to 5°C, the reaction time is controlled at 1h-20h, and the stirring speed is controlled at 100r-500r / min;

[0011] 4) Slowly add 150ml-300ml of deionized water to the solution prepared in step 3) at a dropping speed of 10ml-50ml / h, the reaction temperature is controlled at -10°C to 5°C, the reaction time is controlled at 3h-30h, and the stirring speed is controlled at 100r-500r / min;

[0012] 5) Slowly add the solution prepared in step 4) into a 1500ml-2500ml ice-water mixed bath, stirring while adding, and control the reaction temperature at 0°C;

[0013] 6) Slowly drop 5g-20g of hydrogen peroxide solution into the solution obtained in step 5), stirring while adding, the reaction temperature is controlled at 0°C-5°C, the stirring speed is controlled at 100r / min-300r / min, and the stirring time is 20min-40min;

[0014] 7) Slowly drop a 1%-10% dilute hydrochloric acid solution into the solution prepared in step 6) while stirring, the reaction temperature is controlled at 0°C-5°C, the stirring speed is controlled at 100r-300r / min, the stirring time is 5min-20min, and the mass ratio of potassium permanganate to hydrochloric acid is (2-10):1;

[0015] 8) sealing the solution obtained in step 7) and allowing it to stand at a temperature of 2° C. to 10° C. for 3 to 10 days;

[0016] 9) Pour off the supernatant and repeatedly centrifuge with water until the pH value of the solution is above 5, with a centrifugal speed of 5000-8000 r / min and a centrifugal time of 30 min;

[0017] 10) The multilayer dual-phase graphite oxide solution prepared in 9) is placed at 3° C.-10° C. for subsequent material preparation.

[0018] The beneficial effects of the present invention are:

[0019] (1) Through the dual-phase design of graphite structure, it can be stably dispersed in water and organic solvents while retaining the original crystal structure and excellent physical properties of graphite.

[0020] (2) The preparation method provided by the present invention is simple, low-cost, short-cycle and high-efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a scanning electron microscope image of the dual-phase graphite oxide nanosheet of Example 1;

[0022] Figure 2 The dual-phase graphite oxide nanosheet aqueous dispersion of Example 1;

[0023] Figure 3 is the XRD spectrum of the dual-phase graphite oxide nanosheet aqueous dispersion of Example 1;

[0024] Figure 4 This is a Raman spectrum of the dual-phase graphite sheet of Example 1 and the middle area of ​​the graphite sheet after the surface layer is peeled off;

[0025] Figure 5 The dual-phase graphite oxide nanosheet aqueous dispersion of Example 2;

[0026] Figure 6 is the XRD spectrum of the dual-phase graphite oxide nanosheet aqueous dispersion of Example 2;

[0027] Figure 7 The dual-phase graphite oxide nanosheet aqueous dispersion of Example 3;

[0028] Figure 8 is the XRD spectrum of the dual-phase graphite oxide nanosheet aqueous dispersion of Example 3;

[0029] Fig. 9 The dual-phase graphite oxide nanosheet aqueous dispersion of Example 4;

[0030] Fig.10 is the XRD spectrum of the dual-phase graphite oxide nanosheet aqueous dispersion of Example 4;

[0031] Fig.11 The dual-phase graphite oxide nanosheet aqueous dispersion of Example 5;

[0032] Fig.12 This is the XRD spectrum of the dual-phase graphite oxide nanosheet aqueous dispersion of Example 5. DETAILED DESCRIPTION

[0033] The raw materials used in the present invention, unless otherwise specified, are conventional commercial products, for example, the concentrated sulfuric acid is commercially available concentrated sulfuric acid with a concentration of 98%; the mass fraction of the hydrogen peroxide is 30%. The methods used in the present invention, unless otherwise specified, are conventional methods in the art.

[0034] The embodiments of the present invention are further described below with reference to a plurality of embodiments.

[0035] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0036] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0037] Example 1

[0038] 1) Slowly add 3g of graphite powder into 50ml of concentrated sulfuric acid. The size of the graphite powder is 200 mesh. The reaction temperature is controlled at -5°C, the reaction time is controlled at 3h, and the stirring speed is controlled at 100r / min.

[0039] 2) Slowly adding potassium permanganate powder to the solution obtained in step 1), the mass ratio of graphite to potassium permanganate is 1:6, the reaction temperature is controlled at -5°C, the reaction time is controlled at 3h, and the stirring speed is controlled at 100r / min;

[0040] 3) Slowly add 60 ml of 10% by mass dilute sulfuric acid solution to the solution obtained in step 2) at a dropping speed of 10 ml / h, the reaction temperature is controlled at -5°C, the reaction time is controlled at 6 h, and the stirring speed is controlled at 100 r / min;

[0041] 4) Slowly add 150 ml of deionized water to the solution obtained in step 3) at a dropping speed of 10 ml / h, the reaction temperature is controlled at -5°C, the reaction time is controlled at 15 h, and the stirring speed is controlled at 100 r / min;

[0042] 5) Slowly add the solution prepared in step 4) into a 1500 ml ice-water mixed bath, stirring while adding, and control the reaction temperature at 0°C;

[0043] 6) Slowly drop 5 g of hydrogen peroxide solution into the solution obtained in step 5) while stirring, the reaction temperature is controlled at 0°C, the stirring speed is controlled at 100 r / min, and the stirring time is 20 min;

[0044] 7) Slowly drop 180 g of 1% dilute hydrochloric acid solution into the solution prepared in step 6) while stirring. The reaction temperature is controlled at 0°C, the stirring speed is controlled at 100 r / min, and the stirring time is 5 min.

[0045] 8) sealing the solution obtained in step 7) and allowing it to stand at 2° C. for 3 days;

[0046] 9) Pour off the supernatant and wash repeatedly by centrifugation with water until the pH value of the solution is above 5, with a centrifugal speed of 5000 r / min and a centrifugal time of 30 min;

[0047] 10) The multilayer dual-phase graphite oxide solution prepared in 9) is placed at 3° C. for subsequent material preparation.

[0048] 11) The thickness of the multilayer dual-phase graphene oxide nanosheets prepared in the experiment is 5-7nm. Figure 2 As shown, the aqueous dispersion is uniform and stable.

[0049] according to Figure 3 From the XRD graph of this embodiment shown, it can be seen that two characteristic peaks appear at 2θ=9.96° and 2θ=21.17°, and the corresponding graphite interlayer spacings are 0.89nm and 0.42nm, respectively, which are close to the interlayer spacing of graphene oxide and graphite interlayer spacing, respectively. This indicates that the dual phase is a graphite structure with two different oxidation degrees in the film.

[0050] Figure 4The Raman spectra of the dual-phase graphite sheet of this embodiment and the middle area of ​​the graphite sheet after peeling off the surface layer are shown. The black color is the Raman spectra of the dual-phase graphite sheet, and the appearance of the 2D peak proves the existence of a graphite crystal structure in the graphite sheet; the red color represents the Raman spectra of the middle area of ​​the graphite sheet after peeling off the surface amorphous layer. After peeling off the surface layer, the G peak and the 2D peak are significantly enhanced, proving that the middle area of ​​the dual-phase graphite sheet is an ordered crystal structure of graphite. It can be obtained that the preparation method provided by the present invention can successfully prepare multilayer dual-phase graphite oxide with an outer layer of graphene oxide and an inner layer of graphite.

[0051] Example 2

[0052] 1) Slowly add 3g of graphite powder into 50ml of concentrated sulfuric acid. The size of the graphite powder is 200 mesh. The reaction temperature is controlled at -30°C, the reaction time is controlled at 3h, and the stirring speed is controlled at 100r / min.

[0053] 2) Slowly adding potassium permanganate powder to the solution obtained in step 1), the mass ratio of graphite to potassium permanganate is 1:1, the reaction temperature is controlled at -30°C, the reaction time is controlled at 3h, and the stirring speed is controlled at 100r / min;

[0054] 3) Slowly add 60 ml of 10% by mass dilute sulfuric acid solution to the solution obtained in step 2) at a dropping speed of 60 ml / h, the reaction temperature is controlled at -10°C, the reaction time is controlled at 1 h, and the stirring speed is controlled at 100 r / min;

[0055] 4) Slowly add 150 ml of deionized water to the solution obtained in step 3) at a dropping speed of 10 ml / h, the reaction temperature is controlled at -10°C, the reaction time is controlled at 15 h, and the stirring speed is controlled at 100 r / min;

[0056] 5) Slowly add the solution prepared in step 4) into a 1500 ml ice-water mixed bath, stirring while adding, and control the reaction temperature at 0°C;

[0057] 6) Slowly drop 5 g of hydrogen peroxide solution into the solution obtained in step 5) while stirring, the reaction temperature is controlled at 0°C, the stirring speed is controlled at 100 r / min, and the stirring time is 20 min;

[0058] 7) Slowly drop 50 g of 1% dilute hydrochloric acid solution into the solution prepared in step 6) while stirring. The reaction temperature is controlled at 0°C, the stirring speed is controlled at 100 r / min, and the stirring time is 5 min.

[0059] 8) sealing the solution obtained in step 7) and allowing it to stand at 2° C. for 3 days;

[0060] 9) Pour off the supernatant and wash repeatedly by centrifugation with water until the pH value of the solution is above 5, with a centrifugal speed of 5000 r / min and a centrifugal time of 30 min;

[0061] 10) The multilayer dual-phase graphite oxide solution prepared in 9) is placed at 3° C. for subsequent material preparation.

[0062] 11) The multilayer dual-phase graphene oxide nanosheets prepared in the experiment have a thickness of 40-50 nm and are as follows Figure 5 A homogeneous and stable solution is shown.

[0063] like Figure 6 The XRD graph of this embodiment shown in the figure shows two characteristic peaks at 2θ=10.59° and 2θ=21.53°, and the corresponding graphite interlayer spacings are 0.86nm and 0.41nm, respectively, which are close to the interlayer spacing of graphene oxide and graphite interlayer spacing, respectively. This indicates that the dual phase is a graphite structure with two different oxidation degrees in the film.

[0064] Example 3

[0065] 1) Slowly add 3 g of graphite powder into 200 ml of concentrated sulfuric acid. The size of the graphite powder is 200 mesh. The reaction temperature is controlled at -30 ° C. The reaction time is controlled at 6 h and the stirring speed is controlled at 500 r / min.

[0066] 2) Slowly adding potassium permanganate powder to the solution obtained in step 1), the mass ratio of graphite to potassium permanganate is 1:6, the reaction temperature is controlled at -30°C, the reaction time is controlled at 6h, and the stirring speed is controlled at 500r / min;

[0067] 3) Slowly add 60 ml of 30% by mass dilute sulfuric acid solution to the solution obtained in step 2) at a dropping speed of 30 ml / h, the reaction temperature is controlled at -10°C, the reaction time is controlled at 2 h, and the stirring speed is controlled at 500 r / min;

[0068] 4) Slowly add 150 ml of deionized water to the solution obtained in step 3) at a dropping speed of 30 ml / h, the reaction temperature is controlled at -10°C, the reaction time is controlled at 5 h, and the stirring speed is controlled at 500 r / min;

[0069] 5) Slowly add the solution prepared in step 4) into a 2500 ml ice-water mixed bath, stirring while adding, and control the reaction temperature at 0°C;

[0070] 6) Slowly drop 20 g of hydrogen peroxide solution into the solution obtained in step 5) while stirring, the reaction temperature is controlled at 0°C, the stirring speed is controlled at 100 r / min, and the stirring time is 20 min;

[0071] 7) Slowly drop 100 g of 5% dilute hydrochloric acid solution into the solution prepared in step 6) while stirring. The reaction temperature is controlled at 0°C, the stirring speed is controlled at 300 r / min, and the stirring time is 5 min.

[0072] 8) sealing the solution obtained in step 7) and allowing it to stand at 2° C. for 10 days;

[0073] 9) Pour off the supernatant and repeatedly centrifuge with water until the pH value of the solution is above 5, centrifuge at 8000 r / min, and centrifuge for 30 min;

[0074] 10) The multilayer dual-phase graphite oxide solution prepared in 9) is placed at 3° C. for subsequent material preparation.

[0075] 11) The multilayer dual-phase graphene oxide nanosheets prepared in the experiment have a thickness of 20-30 nm and appear as follows Figure 7 A homogeneous and stable solution is shown.

[0076] like Figure 8 The XRD graph of this embodiment shown in the figure shows two characteristic peaks at 2θ=9.84° and 2θ=20.12°, and the corresponding graphite interlayer spacings are 0.9nm and 0.44nm, respectively, which are close to the interlayer spacing of graphene oxide and graphite interlayer spacing, respectively. This indicates that the dual phase is a graphite structure with two different oxidation degrees in the film.

[0077] Example 4

[0078] 1) Slowly add 3g of graphite powder into 200ml of concentrated sulfuric acid. The size of the graphite powder is 500 mesh. The reaction temperature is controlled at 5°C, the reaction time is controlled at 3h, and the stirring speed is controlled at 500r / min.

[0079] 2) Slowly adding potassium permanganate powder to the solution obtained in step 1), the mass ratio of graphite to potassium permanganate is 1:6, the reaction temperature is controlled at 5° C., the reaction time is controlled at 3 h, and the stirring speed is controlled at 500 r / min;

[0080] 3) Slowly add 200 ml of 10% by mass dilute sulfuric acid solution to the solution obtained in step 2) at a dropping speed of 10 ml / h, a reaction temperature of 5°C, a reaction time of 20 h, and a stirring speed of 100 r / min;

[0081] 4) Slowly add 300 ml of deionized water to the solution obtained in step 3) at a dropping speed of 10 ml / h, a reaction temperature of 5° C., a reaction time of 30 h, and a stirring speed of 100 r / min;

[0082] 5) Slowly add the solution prepared in step 4) into a 1500 ml ice-water mixed bath, stirring while adding, and control the reaction temperature at 0°C;

[0083] 6) Slowly drop 5 g of hydrogen peroxide solution into the solution obtained in step 5) while stirring, the reaction temperature is controlled at 0°C, the stirring speed is controlled at 100 r / min, and the stirring time is 20 min;

[0084] 7) Slowly drop 50 g of 1% dilute hydrochloric acid solution into the solution prepared in step 6) while stirring. The reaction temperature is controlled at 5° C., the stirring speed is controlled at 100 r / min, and the stirring time is 20 min.

[0085] 8) sealing the solution obtained in step 7) and allowing it to stand at 10° C. for 10 days;

[0086] 9) Pour off the supernatant and repeatedly centrifuge with water until the pH value of the solution is above 5, centrifuge at 5000 r / min, and centrifuge for 5 h;

[0087] 10) The multilayer dual-phase graphite oxide solution prepared in 9) was placed at 8°C for subsequent material preparation, and was presented as follows Fig. 9 A homogeneous and stable solution is shown.

[0088] like Fig.10 The XRD graph of this embodiment shown in the figure shows two characteristic peaks at 2θ=10.11° and 2θ=20.58°, and the corresponding graphite interlayer spacings are 0.88nm and 0.43nm, respectively, which are close to the interlayer spacing of graphene oxide and graphite interlayer spacing, respectively. This indicates that the dual phase is a graphite structure with two different oxidation degrees in the film.

[0089] Example 5

[0090] 1) Slowly add 3g of graphite powder into 200ml of concentrated sulfuric acid. The size of the graphite powder is 200 mesh. The reaction temperature is controlled at -20°C, the reaction time is controlled at 4h, and the stirring speed is controlled at 500r / min.

[0091] 2) Slowly adding potassium permanganate powder to the solution prepared in step 1), the mass ratio of graphite to potassium permanganate is 1:5, the reaction temperature is controlled at -20°C, the reaction time is controlled at 4h, and the stirring speed is controlled at 500r / min;

[0092] 3) 150 ml of a 10%-30% dilute sulfuric acid solution was slowly added dropwise to the solution obtained in step 2) at a dropping speed of 50 ml / h, the reaction temperature was controlled at -10°C, the reaction time was controlled at 3 h, and the stirring speed was controlled at 500 r / min;

[0093] 4) Slowly add 300 ml of deionized water to the solution obtained in step 3) at a dropping speed of 50 ml / h, the reaction temperature is controlled at -10°C, the reaction time is controlled at 3 h, and the stirring speed is controlled at 500 r / min;

[0094] 5) Slowly add the solution prepared in step 4) into a 2000 ml ice-water mixed bath, stirring while adding, and control the reaction temperature at 0°C;

[0095] 6) Slowly drop 20 g of hydrogen peroxide solution into the solution obtained in step 5) while stirring, the reaction temperature was controlled at 5° C., the stirring speed was controlled at 300 r / min, and the stirring time was 40 min;

[0096] 7) Slowly drop 50 g of 10% dilute hydrochloric acid solution into the solution obtained in step 6) while stirring, the reaction temperature is controlled at 2° C., the stirring speed is controlled at 200 r / min, and the stirring time is 20 min;

[0097] 8) sealing the solution obtained in step 7) and allowing it to stand at 2° C. for 3 days;

[0098] 9) Pour off the supernatant and repeatedly centrifuge with water until the pH value of the solution is above 5, centrifuge at 8000 r / min, and centrifuge for 30 min;

[0099] 10) The multilayer dual-phase graphite oxide solution prepared in 9) was placed at 10°C for subsequent material preparation, and was presented as follows Fig.11 A homogeneous and stable solution is shown.

[0100] like Fig.12 The XRD graph of this embodiment shown in the figure shows two characteristic peaks at 2θ=10.25° and 2θ=22.15°, and the corresponding graphite interlayer spacings are 0.86nm and 0.4nm, respectively, which are close to the interlayer spacing of graphene oxide and graphite interlayer spacing, respectively. This indicates that the dual phase is a graphite structure with two different oxidation degrees in the film.

[0101] The above embodiments describe in detail the structure, features and effects of the present invention. The above are only preferred embodiments of the present invention. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which do not exceed the scope covered by the specification, should be within the protection scope of the present invention.

[0102] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A multilayer dual-phase graphite oxide nanosheet, characterized in that: The surface of the nanosheet is a graphene oxide structure, and the middle layer is a graphite crystal phase structure.

2. A method for preparing multilayer dual-phase graphite oxide nanosheets, characterized in that: The following steps are involved: 1) Add graphite powder to 50ml-200ml concentrated sulfuric acid, the size of the graphite powder is 200 mesh-500 mesh, control the reaction temperature and reaction time, and control the stirring speed at 100r-500r / min; 2) Add potassium permanganate powder, control the reaction temperature and reaction time, and control the stirring speed at 100r-500r / min; 3) Add 60ml-200ml of dilute sulfuric acid solution dropwise at a rate of 10ml-60ml / h, control the reaction temperature at -10°C to 5°C, the reaction time at 1h-20h, and the stirring speed at 100r-500r / min; 4) Add 150ml-300ml of deionized water dropwise at a rate of 10ml-50ml / h, control the reaction temperature at -10°C to 5°C, the reaction time at 3h-30h, and the stirring speed at 100r-500r / min; 5) Add the solution prepared in step 4) to a 1500ml-2500ml ice-water mixed bath, stirring while adding, and control the reaction temperature at 0°C; 6) Add hydrogen peroxide solution dropwise to remove excess potassium permanganate that has not reacted until no more bubbles are generated; 7) Add dilute hydrochloric acid solution dropwise while stirring, the reaction temperature is controlled at 0℃-5℃, the stirring speed is controlled at 100r-300r / min, and the stirring time is 5min-20min; the mass ratio of potassium permanganate to hydrochloric acid is 2:1-10:1; 8) sealing the solution obtained in step 7) and allowing it to stand at a temperature of 2° C. to 10° C. for 3 to 10 days; 9) Pour off the supernatant, and repeatedly centrifuge and wash at a speed of 5000r-8000r / min until the pH value of the solution is above 5; collect the centrifugal product to obtain dual-phase graphite oxide.

3. The preparation method according to claim 2, characterized in that: The mass ratio of graphite to potassium permanganate in step 1) and step 2) is 1:1-1:

6.

4. The preparation method according to claim 2, characterized in that: In step 1), the reaction temperature is controlled at -30°C to 5°C, and the reaction time is controlled at 3h to 6h.

5. The preparation method according to claim 2, characterized in that: In step 2), the reaction temperature is controlled at -30°C to 5°C, and the reaction time is controlled at 3h to 6h.

6. The preparation method according to claim 2, characterized in that: The mass fraction of the dilute sulfuric acid in step 3) is 10%-30%.

7. The preparation method according to claim 2, characterized in that: The mass of the hydrogen peroxide in step 6) is 5g-20g.

8. The preparation method according to claim 2, characterized in that: The mass fraction of the dilute hydrochloric acid in step 7) is 1%-10%.

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