Porous silicon-based nanomaterials, methods of synthesis and applications thereof

Abstract

The application discloses a porous silicon-based nanomaterial, which comprises a silicon-based nanomaterial and a porous silicon-based nanomaterial with surface functional group modification, has a pore size of 2-200 nm, a specific surface area of 100-800 m 2 / g, and a pore volume of 0.5-5.0 cm 3 / g. The application further discloses a preparation method of the porous silicon-based nanomaterial, and application of the nanomaterial in protein enrichment and proteomic sample preparation of a biological sample.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterial application, and relates to a type of porous silicon-based nanomaterial, a synthesis method and an application thereof. Background Art

[0002] Proteomics is the study of the composition, structure, function, and interactions of all proteins in an organism. It aims to systematically and comprehensively understand biological processes at the protein level, including the onset and progression of disease and cellular metabolism. The diversity and complexity of proteins in organisms make proteomics research more challenging, while also providing more information on potential functions and interactions. Compared to genomics, transcriptomics, and metabolomics, proteomics research can reveal the relationship between protein structure and function, infer the functions of unknown proteins, and predict the interactions between proteins and other molecules. This is of great significance for drug design, disease diagnosis, and treatment.

[0003] Mass spectrometry technology has the advantages of rapidity, high sensitivity, high resolution, and high throughput. It can accurately measure the relative molecular mass, amino acid sequence, post-translational modification, and protein-protein interactions of proteins and peptides, making it the preferred method in proteomics research. MS-based proteomics has become increasingly mature in the past decade. The development of advanced high-resolution mass spectrometry instruments has promoted large-scale analysis of proteomics research and provided a deeper understanding of the properties of proteins (such as post-translational modifications, interactions, and biochemical functions). The mass spectrometry-based protein workflow includes (1) sample preparation, (2) peptide separation, (3) mass spectrometry detection, and (4) data analysis. Sample preparation is a key stage that affects the overall efficiency of proteomics research, but the low reproducibility and low throughput of sample preparation have become the main bottlenecks for many cutting-edge biomedical applications.

[0004] In-solution digestion-based sample preparation is a traditional yet popular method for digesting proteins into peptides. Its workflow includes protein extraction from biological samples, protein denaturation / purification, reduction, alkylation, enzymatic digestion, desalting, and peptide isolation. First, protein extraction from biological samples is challenging, as protein concentrations in biological samples span at least six orders of magnitude. For example, plasma contains approximately 10,000 proteins, ranging from albumin at 35-50 mg / mL to low-abundance proteins at pg / mL. Plasma and serum samples often require depletion of high-abundance proteins to identify low-abundance proteins. Immunodepletion (spin columns and LC) and magnetic beads can remove up to 20 of the most abundant plasma proteins, but this can result in carryover, low reproducibility, low throughput, and loss of albumin-bound proteins. Second, protein denaturation requires high concentrations of denaturants, such as 8M urea, to solubilize proteins and denature their three-dimensional structure. High denaturant concentrations inhibit enzymatic digestion, so protein samples are often diluted to reduce the urea concentration before enzyme addition. At the same time, the sample needs to be incubated for at least 30 minutes after adding reducing agents such as dithiothreitol, tris(2-carboxyethyl)phosphine (TCEP), and tris(3-hydroxypropyl)phosphine to reduce the sample. Further addition of alkylating agents such as iodoacetamide and iodoacetic acid requires incubation in the dark. Finally, enzymatic digestion of proteins requires a long enzymatic hydrolysis time (usually overnight) and a large amount of starting material (usually >100μg), which is extremely unfavorable for the processing of trace or precious biological samples. Due to the multi-step operation in sample preparation, the in-solution digestion method has a large amount of sample loss, which limits its application in proteomic analysis with limited starting material. At the same time, the cumbersome workflow is inefficient and is not suitable for clinical proteomics and in vivo studies that require high sample processing throughput, reproducibility, and sensitivity.

[0005] Sample preparation is the most critical stage in proteomics research, but it is time-consuming, labor-intensive and prone to errors. Researchers have developed many methods to replace in-solution digestion, including on-membrane digestion (MStern, FASP, and fa-SPEED), magnetic bead-based digestion (proteomic reactor, SP3, and C4-tip), and digestion based on immobilized enzyme reactors to reduce time, increase throughput and improve reproducibility. Currently, these methods have also been successfully applied to proteomics research, but there are still certain limitations in sample preparation for clinical research and biomedical applications. Therefore, there is an urgent need for a sample preparation technology that improves the accuracy and reproducibility of the sample preparation process, integrates multiple steps of sample preparation, thereby reducing sample loss caused by manual transfer steps, simplifying the workflow, and improving the efficiency of proteomics research. Summary of the Invention

[0006] In response to the above problems, the present invention provides a type of proteomics sample preparation technology based on porous silicon-based nanomaterials. The porous silicon-based nanomaterials proposed in the present invention have a mesoporous (pore diameter of 2-50nm) and / or macroporous (pore diameter>50nm) structure and a large specific surface area, which can effectively adsorb and enrich protein molecules of appropriate size. At the same time, the material of the present invention can also introduce nanopores of appropriate size through different synthesis methods, which can not only expand the specific surface area, modify more functional groups on the surface, enhance specific recognition performance, but also have a volume exclusion effect on molecules of certain sizes, significantly improving the enrichment efficiency of protein molecules. At the same time, the protein denaturation, reduction and alkylation steps are integrated into one step, which greatly shortens the sample preparation time.

[0007] The present invention provides a class of porous silicon-based nanomaterials, including silicon-based nanomaterials with a mesoporous structure (pore size of 2-50 nm) and / or a macroporous structure (pore size > 50 nm) and porous silicon-based nanomaterials modified with surface functional groups;

[0008] The porous silicon-based nanomaterial has a pore size of 2-200 nm and a specific surface area of ​​100-800 m 2 / g, pore volume of 0.5-5.0cm 3 / g porous silica material; preferably, a pore size of 50-200nm, a specific surface area of ​​100-800m 2 / g, pore volume of 0.5-5.0cm 3 / g of macroporous ordered silica materials.

[0009] The porous silicon-based nanomaterial can be modified with surface functional groups to synthesize a functionalized porous silicon-based nanomaterial.

[0010] Among them, the surface functional groups in the surface functional group modification refer to hydroxyl-OH, thiol-SH, amino-NH2, nitro-NO2, carboxyl-COOH, sulfonic acid group-SO3H, phosphate group-PO3H2, carbamate group-NHCOCH3, azido-N3, charged group, boronic acid group, aromatic group, carbohydrate modification, metal oxide modification, halogen modification, silicone modification, aldehyde and ketone modification, polyethylene glycol modification, hydrophobic group, hydrophilic group, cationic coating, anionic coating, etc.

[0011] The present invention also provides a method for preparing porous silicon-based nanomaterials, the specific steps of which are as follows:

[0012] (1) dissolving a surfactant and an inorganic salt in a buffer solution to obtain a uniform solution, and then adding a silicon source to react for a certain period of time to form a uniform solution;

[0013] (2) subjecting the uniform solution obtained in step (1) to hydrothermal treatment;

[0014] (3) The solution obtained in step (2) is filtered, washed, dried and then calcined to obtain a porous silica material.

[0015] In the step (1), the surfactant is selected from one or more of quaternary ammonium salt cationic surfactants, primary amine salt cationic surfactants, long-chain alkyl sulfate, phosphate, carboxylate anionic surfactants, long-chain alkylamine, polyoxyethylene ether and block copolymer nonionic surfactants; preferably, it is a block copolymer nonionic surfactant.

[0016] The inorganic salt is selected from one or more of sulfates, phosphates, carbonates and carboxylates, etc.; preferably, it is phosphate.

[0017] The concentration of the inorganic salt is 0.01-1.0M; preferably, 0.3M.

[0018] The buffer solution is a NaH2PO4-Na2HPO4, H3PO4-Na2HPO4, NaAc-HAc or H2CO3-NaHCO3 buffer system with a pH of 2-7, preferably, NaH2PO4-Na2HPO4, pH=6.

[0019] The silicon source is selected from tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), etc.; preferably, it is TMOS.

[0020] The mass ratio of the surfactant to the silicon source is (0.5-2):1; preferably, it is 0.7:1.

[0021] The reaction temperature is 25-70°C; preferably, 30°C.

[0022] The reaction time is 10-48 hours; preferably, 12 hours.

[0023] In the step (2), the temperature of the hydrothermal treatment is 50-200°C; preferably, 120°C.

[0024] The hydrothermal treatment time is 10-48 hours; preferably, 12 hours.

[0025] In the step (3), the drying temperature is 25-70°C; preferably, 40°C.

[0026] The drying time is 5-12 hours; preferably, 8 hours.

[0027] The calcination temperature is 300-800°C; preferably, 500°C.

[0028] The calcination time is 2-10 hours; preferably, 5 hours.

[0029] The present invention also provides porous silicon-based nanomaterials prepared by the above method.

[0030] The porous silicon-based nanomaterial has a pore size of 2-200 nm and a specific surface area of ​​100-800 m 2 / g, pore volume of 0.5-5.0cm 3 / g of macroporous ordered silica material; preferably, a pore size of 50-200nm and a specific surface area of ​​100-800m 2 / g, pore volume of 0.5-5.0cm 3 / g of macroporous ordered silica materials.

[0031] The present invention also provides application of the porous silicon-based nanomaterial in protein enrichment and proteomics sample preparation in biological samples.

[0032] In a specific embodiment, in the application of the present invention, the protein denaturation, reduction and alkylation steps are integrated into a single step.

[0033] Compared with existing materials used for proteomics sample preparation, the material synthesis of the present invention has the following advantages: low raw material cost, mild and controllable reaction conditions, simple operation, and easy synthesis; by changing experimental conditions such as feed ratio, reaction temperature, buffer solution pH, etc., silicon-based materials with different pore sizes and / or specific surface areas can be synthesized; at the same time, the material surface can be modified with functional groups to increase its specific enrichment of proteins; the synthesized porous silicon-based nanomaterial has a suitable pore size and a large specific surface area, has been successfully used for protein enrichment, and has excellent performance, and has broad application prospects in the field of proteomics sample preparation.

[0034] The present invention also provides a method for preparing a proteomic sample from a biological sample based on a porous silicon-based nanomaterial. The method comprises: first, adding the porous silicon-based nanomaterial to the biological sample to enrich the protein, and then performing protein lysis, reduction and alkylation, protein digestion, and protein desalting to obtain the proteomic sample. In a specific embodiment, the method comprises the following steps:

[0035] (1) Protein extraction: cells, tissues and other samples are added with corresponding lysis buffer to homogenize the samples and then protein solution is extracted. Biological fluids (serum, plasma, etc.) are directly used without dilution;

[0036] (2) Protein enrichment: The porous silicon-based nanomaterials were added to the protein sample (protein: material (w:w) = 0.2-10:1), placed on a thermomixer at 37°C, incubated at 300-1500 rpm for 5-30 minutes, centrifuged, the supernatant removed, and washed three times;

[0037] (3) Protein lysis, reduction and alkylation: add protein lysis, reduction and alkylation buffer reagents, place on a thermomixer at 70-95°C, 300-1500 rpm and incubate for 5-60 minutes; the final concentration of protein lysis reagent is 5-50 mM, the final concentration of reducing reagent is 5-100 mM, the final concentration of alkylating reagent is 10-100 mM, the buffer:protein = 1-100:1, and the buffer pH is 7-8.5;

[0038] (4) Protein digestion: Add digestive enzyme at a ratio of 1:20 to 1:100 based on the BCA protein quantification results. Incubate on a thermomixer at 37°C, 300-1500 rpm for 0.5-6 hours. Add stop reagent and mix well to stop the enzymatic reaction. Centrifuge at 10,000-20,000 g for 1-10 minutes and aspirate the supernatant.

[0039] (5) Protein desalting: The supernatant was loaded into a C18 desalting column for desalting. The eluate was concentrated using a vacuum refrigerated centrifugal concentrator and stored at -80°C for LC-MS / MS detection.

[0040] The proteomics sample preparation method provided by the present invention has the following advantages over existing sample preparation methods: the sample preparation technology of the present invention does not require the pre-removal of high-abundance proteins, and achieves indiscriminate enrichment of protein samples through surface modification of porous silicon-based nanomaterials and the combination of different porous silicon-based nanomaterials, thereby achieving indiscriminate enrichment and concentration normalization of high- and low-abundance proteins within the pores of the nanomaterials; by integrating multiple steps of protein sample preparation, the workflow is simplified, the time is greatly shortened, and work efficiency is improved, so that sample preparation can be completed within 1 to 8 hours; the materials used in this technology are inexpensive, with a cost of 0.2 yuan per 100 μl sample, and it is expected to be widely used in clinical testing in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 This is a characterization picture of the porous silicon-based nanomaterial prepared in specific embodiment 1 of the present invention. Figure 1a is a transmission electron microscope TEM characterization image, Figure 1 b is the SEM characterization image, Figure 1 c is the nitrogen adsorption-desorption isotherm characterization diagram.

[0043] Figure 2 The porous silicon-based nanomaterials in specific embodiments 5 and 6 of the present invention are enriched with fetal bovine serum (FBS) ( Figure 2 a) and plasma samples ( Figure 2 b) The number of protein groups identified by LC-MS / MS was compared with the protein identification results of samples processed by commercial kits. DETAILED DESCRIPTION

[0044] The present invention is further described in detail with reference to the following specific examples and accompanying drawings. The processes, conditions, experimental methods, etc. for implementing the present invention, except for those specifically mentioned below, are common knowledge and common common sense in the art and are not particularly limited by the present invention.

[0045] Example 1: Preparation of porous silicon-based nanomaterials

[0046] 0.7 g of block copolymer P123 (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer PEO-PPO-PEO), 0.3 g of CTAB, and 1.4 g of Na2SO4 were dissolved in 30 g of NaAc-HAc buffer solution with a pH of 4 and reacted at 30°C for 1 h. 1.5 g of TMOS was added to the homogeneous solution and the reaction was continued for 12 hours. The solution was then hydroheated at 120°C for 12 hours, filtered, washed, and dried. After drying, the solution was calcined at 500°C for 5 hours to obtain a pore size of 50 nm and a specific surface area of ​​217 m 2 / g, pore volume 3.9cm 3 / g of porous silica nanomaterials.

[0047] Figure 1 This is a characterization picture of the porous silicon-based nanomaterial prepared in Example 1. Figure 1 a is a transmission electron microscope TEM characterization image, Figure 1 b is the SEM characterization image, Figure 1 c is the nitrogen adsorption-desorption isotherm characterization diagram.

[0048] Example 2: Preparation of porous silicon-based nanomaterials

[0049] 0.7 g of block copolymer F-127 (poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) PPG-PEG-PPG), 0.3 g of CTAB and 1.4 g of Na3PO4 were dissolved in 30 g of NaH2PO4-Na2HPO4 buffer solution with a pH of 6 and reacted at 30°C for 1 h. 1.5 g of TMOS was added to the above homogeneous solution and the reaction was continued for 12 hours. The product was then hydroheated at 120°C for 12 hours, filtered, washed and dried. After drying, the product was calcined at 500°C for 5 hours to obtain a product with a pore size of 20 nm and a specific surface area of ​​291 m 2 / g, pore volume 2.7cm 3 / g of porous silica nanomaterials.

[0050] Example 3: Preparation of porous silicon-based nanomaterials

[0051] 1.4 g of block copolymer F-127, 0.6 g of CTAB and 1.4 g of Na3PO4 were dissolved in 30 g of NaH2PO4-Na2HPO4 buffer solution with a pH of 6 and reacted at 30°C for 1 h. 1.5 g of TMOS was added to the homogeneous solution and the reaction was continued for 12 h. The solution was then hydrothermaled at 120°C for 12 h, filtered, washed and dried. After drying, the solution was calcined at 500°C for 5 h to obtain a pore size of 70 nm and a specific surface area of ​​174 m 2 / g, pore volume 3.1cm 3 / g of porous silica nanomaterials.

[0052] Example 4: Preparation of porous silicon-based nanomaterials

[0053] 0.7 g of block copolymer F-127, 0.3 g of CTAB and 1.4 g of Na3PO4 were dissolved in 30 g of NaH2PO4-Na2HPO4 buffer solution with a pH of 6 and reacted at 50°C for 1 h. 1.0 g of TEOS was added to the homogeneous solution and the reaction was continued for 12 hours. The solution was then hydrothermaled at 120°C for 12 hours, filtered, washed and dried. After drying, the solution was calcined at 500°C for 5 hours to obtain a pore size of 10 nm and a specific surface area of ​​332 m 2 / g, pore volume 1.0cm 3 / g of porous silica nanomaterials.

[0054] Example 5: Porous silicon-based nanomaterials for proteomics sample preparation of fetal bovine serum (FBS)

[0055] Step 1: Prepare a high-concentration mother solution of porous silicon-based nanomaterials. Mix equal volumes of the mother solution of porous silicon-based nanomaterials prepared in Example 1 of the present invention and equal volumes of fetal bovine serum sample, incubate on a constant temperature mixer at 37°C and 1000 rpm for 20 minutes, remove the supernatant by centrifugation, and wash the precipitate three times.

[0056] Step 2: Add 10 mM sodium deoxycholate (SDC), 5 mM tris(2-carboxyethyl)phosphine hydrochloride (TCEP-HCl), and 20 mM iodoacetamide (IAA) to the sample in step 1, and place in a thermomixer at 95°C for 10 min.

[0057] Step 3: After the sample returns to room temperature, add trypsin and incubate at 37°C, 1000 rpm for 2 h.

[0058] Step 4: After the enzymatic hydrolysis is completed, add a 1% formic acid aqueous solution to stop the enzymatic hydrolysis reaction, centrifuge at 13000g for 3 minutes, and aspirate the supernatant;

[0059] Step 5: After desalting the enzymatic hydrolysate using a C18 desalting column, the sample was concentrated and reconstituted with 0.1% formic acid aqueous solution, and protein identification was performed using LC-MS / MS.

[0060] After the protein in the sample was enriched by porous silicon-based nanomaterials and sample pretreatment, the results of LC-MS / MS detection were analyzed ( Figure 2 a) Compared with serum samples without material treatment and samples treated with commercial kits, the protein sample preparation process based on porous silicon nanomaterials identified more proteomes.

[0061] Example 6: Porous silicon-based nanomaterials for proteomics sample preparation of plasma samples

[0062] Step 1: Prepare a high-concentration mother solution of porous silicon-based nanomaterials. Mix equal volumes of the mother solution of porous silicon-based nanomaterials prepared in Example 1 of the present invention and equal volumes of plasma sample, then incubate in a constant temperature mixer at 37°C and 1000 rpm for 20 minutes. Centrifuge to remove the supernatant, and wash the precipitate three times.

[0063] Step 2: Add 10 mM sodium deoxycholate (SDC), 5 mM tris(2-carboxyethyl)phosphine hydrochloride (TCEP-HCl), and 20 mM iodoacetamide (IAA) to the sample in step 1, and place in a thermomixer at 95°C for 5 min.

[0064] Step 3: After the sample returns to room temperature, add trypsin and incubate at 37°C, 1000 rpm for 2 h.

[0065] Step 4: After the enzymatic hydrolysis is completed, add a 1% formic acid aqueous solution to stop the enzymatic hydrolysis reaction, centrifuge at 13000g for 3 minutes, and aspirate the supernatant;

[0066] Step 5: After desalting the enzymatic hydrolysate using a C18 desalting column, the sample was concentrated and reconstituted with 0.1% formic acid aqueous solution, and protein identification was performed using LC-MS / MS.

[0067] After the protein in the sample was enriched by porous silicon-based nanomaterials and sample pretreatment, the results of LC-MS / MS detection were analyzed ( Figure 2 b) Compared with plasma samples that were not treated with the material and samples treated with commercial kits, the protein sample preparation process based on porous silicon-based nanomaterials identified more proteomes, indicating that the porous silicon-based nanomaterials in the present invention have the advantages of low cost, simplicity and high efficiency in protein sample preparation.

[0068] The protection content of the present invention is not limited to the above embodiments. Without departing from the spirit and scope of the present invention, changes and advantages that can be thought of by those skilled in the art are included in the present invention and are protected by the appended claims.

Claims

1. Application of porous silicon-based nanomaterials in proteomics sample preparation, characterized in that: In the application, the protein denaturation, reduction and alkylation steps are integrated into one step; the porous silicon-based nanomaterials include silicon-based nanomaterials with mesoporous and / or macroporous structures and porous silicon-based nanomaterials with surface functional group modifications; The preparation method of the porous silicon-based nanomaterial comprises the following steps: Step (1): dissolving a surfactant and an inorganic salt in a buffer solution to obtain a uniform solution, adding a silicon source and continuing the reaction for a certain period of time to form a uniform solution; the inorganic salt is selected from one or more of sulfates, phosphates, carbonates and carboxylates; Step (2): subjecting the uniform solution obtained in step (1) to hydrothermal treatment; Step (3): Filter the solution obtained in step (2), wash, dry and then calcine to obtain a porous silicon-based nanomaterial.

2. The use according to claim 1, characterized in that The pore size of the mesoporous structure is 2-50 nm; the pore size of the macroporous structure is >50 nm; and / or, The porous silicon-based nanomaterial has a pore size of 2-200 nm and a specific surface area of ​​100-800 m 2 / g, pore volume of 0.5-5.0 cm 3 / g.

3. The use according to claim 1, characterized in that In the step (1), The surfactant is selected from one or more of quaternary ammonium salt cationic surfactants, primary amine salt cationic surfactants, long-chain alkyl sulfate, phosphate, carboxylate anionic surfactants, long-chain alkylamine, polyoxyethylene ether and block copolymer nonionic surfactants; The concentration of the inorganic salt is 0.01-1.0M; The silicon source is selected from one of tetramethyl orthosilicate TMOS and tetraethyl orthosilicate TEOS; The mass ratio of the surfactant to the silicon source is (0.5-2):1; The reaction temperature is 25-70°C; and / or, The reaction time is 10-48 hours.

4. The use according to claim 1, wherein In the step (2), the temperature of the hydrothermal treatment is 50-200° C.; and / or the time of the hydrothermal treatment is 10-48 hours.

5. The use according to claim 1, characterized in that In the step (3), the drying temperature is 25-70°C; the drying time is 5-12 hours; the calcination temperature is 300-800°C; and / or the calcination time is 2-10 hours.

6. A method for preparing proteomics samples in biological samples using porous silicon-based nanomaterials, characterized in that: Adding the porous silicon-based nanomaterial to a protein sample, performing protein enrichment, protein lysis, reduction and alkylation, protein digestion, and protein desalting to obtain the proteomics sample; The porous silicon-based nanomaterials include silicon-based nanomaterials with mesoporous and / or macroporous structures and porous silicon-based nanomaterials with surface functional group modification; The preparation method of the porous silicon-based nanomaterial comprises the following steps: Step (1): dissolving a surfactant and an inorganic salt in a buffer solution to obtain a uniform solution, adding a silicon source and continuing the reaction for a certain period of time to form a uniform solution; the inorganic salt is selected from one or more of sulfates, phosphates, carbonates and carboxylates; Step (2): subjecting the uniform solution obtained in step (1) to hydrothermal treatment; Step (3): Filter the solution obtained in step (2), wash, dry and then calcine to obtain a porous silicon-based nanomaterial.

7. The method according to claim 6, wherein The pore size of the mesoporous structure is 2-50 nm; the pore size of the macroporous structure is >50 nm; and / or, The porous silicon-based nanomaterial has a pore size of 2-200 nm and a specific surface area of ​​100-800 m 2 / g, pore volume of 0.5-5.0 cm 3 / g.

8. The method according to claim 6, wherein In the step (1), The surfactant is selected from one or more of quaternary ammonium salt cationic surfactants, primary amine salt cationic surfactants, long-chain alkyl sulfate, phosphate, carboxylate anionic surfactants, long-chain alkylamine, polyoxyethylene ether and block copolymer nonionic surfactants; The concentration of the inorganic salt is 0.01-1.0M; The silicon source is selected from one of tetramethyl orthosilicate TMOS and tetraethyl orthosilicate TEOS; The mass ratio of the surfactant to the silicon source is (0.5-2):1; The reaction temperature is 25-70°C; and / or, The reaction time is 10-48 hours.

9. The method according to claim 6, wherein In the step (2), the temperature of the hydrothermal treatment is 50-200° C.; and / or the time of the hydrothermal treatment is 10-48 hours.

10. The method according to claim 6, wherein In the step (3), the drying temperature is 25-70°C; the drying time is 5-12 hours; the calcination temperature is 300-800°C; and / or the calcination time is 2-10 hours.

Images