Preparation method of high specific surface area nanometer cerium phosphate material

Abstract

This invention discloses a method for preparing high specific surface area cerium phosphate nanoparticles. The modified corn starch in this invention exhibits good water solubility, resulting in a solution with good suspension and stability after dissolving in water. This suspension stability provides a spatial carrier for the formation of cerium phosphate nanoparticles. A network structure is formed through hydrogen bonding between the molecular weight chains of the modified corn starch, allowing control over the uniformity of cerium phosphate particle size. Different specific surface area values ​​of cerium phosphate can be controlled by adjusting the concentration of the modified corn starch. The modified corn starch can be removed through subsequent high-temperature sintering and washing, ultimately yielding high-purity cerium phosphate nanoparticles. These nanoparticles possess uniformity and high specific surface area, making them suitable for applications in electrode materials, adsorbent materials, luminescent materials, and polymer nanofillers.

Description

Technical Field

[0001] This invention belongs to the field of rare earth material preparation technology, specifically relating to a method for preparing high specific surface area nano-cerium phosphate material. Background Technology

[0002] Rare earth elements, due to their 4f electron characteristic, possess many unique physicochemical properties, as do their compounds. Cerium phosphate, a rare earth compound, exhibits electrical conductivity, fluorescence, and catalytic activity, making it suitable for use as a mesoporous material, conductive material, luminescent material, catalytic material, humidity sensor, and thermal insulation material. When fabricated at the nanoscale, it can be used as an adsorbent material, mounted on electrodes, to redox small molecule compounds. This allows for the detection of minute amounts of these compounds via electrochemical signals, offering high sensitivity and stable testing characteristics.

[0003] Smaller rare-earth cerium phosphate particle sizes result in larger specific surface areas and stronger redox capabilities, which are more advantageous for fabricating highly sensitive detection materials. CN 101704543 A discloses a method for preparing cerium phosphate nanowires, including: preparing Ce... 3+ Salt solution in PO4 3- A mixture of salt solutions is prepared, the pH of which is adjusted to 0.8–1.5. The mixture is stirred for 0.3–1.5 h, and then aged in a water bath at 90–95 °C for at least 2 h under normal pressure to obtain hexagonal cerium phosphate nanowires. The optimal nanoscale size is an average diameter of 26 nm and an average length of 460 nm. CN 101935026 A discloses a method for hydrothermal synthesis of cerium phosphate nanospheres, including: controlling Ce... 3+ A cerium salt aqueous solution with a molar ratio of 1:1 to 10 was mixed with a 0.1–0.8 mol / L polyphosphoric acid aqueous solution, and 0.1–5% (mass fraction) of dispersant was added. Under heating and vigorous stirring, the mixture was allowed to become clear. The solution was then placed in a reactor for a hydrothermal reaction. After the reaction, the product was cooled to room temperature, washed, dried, and subjected to calcination heat treatment to obtain cerium phosphate micro-nanospheres with a diameter of several hundred nanometers. The literature "Synthesis, Characterization, and Exploration of Propane Oxidative Dehydrogenation of Mesoporous Cerium Phosphate Catalysts" reports the synthesis of a catalyst with a specific surface area of ​​152.5 μm using surfactant F172 as a template via a hydrothermal method. 2 / g of nano-cerium phosphate. The above methods are still quite complex and costly, making them difficult to apply industrially. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the prior art and provide a method for preparing high specific surface area nano-cerium phosphate materials.

[0005] The technical solution of the present invention is as follows:

[0006] A method for preparing high specific surface area cerium phosphate nanomaterials includes the following steps:

[0007] (1) Mix modified corn starch with deionized water, heat and stir to dissolve, cool to room temperature and filter to obtain modified corn starch solution;

[0008] (2) Mix phosphate with deionized water, stir to dissolve at room temperature, and then filter to obtain a phosphate solution;

[0009] (3) Mix soluble cerium salt with deionized water, stir to dissolve at room temperature, and then filter to obtain a cerium salt solution;

[0010] (4) At room temperature, while stirring, slowly add the above phosphate solution to the above modified corn starch solution. After the addition is complete, continue stirring for 3-5 hours and adjust the pH to 4-6 with phosphate solution.

[0011] (5) At room temperature, while stirring, add the above cerium salt solution dropwise to the material obtained in step (4) over 50-80 minutes. After the addition is complete, continue stirring and reacting for 5-8 hours.

[0012] (6) The material obtained in step (5) is subjected to a hydrothermal reaction. The conditions for the hydrothermal reaction are: 115-125℃, 3-5h; 145-155℃, 5-7h; 195-205℃, 7-9h.

[0013] (7) After filtering the material obtained in step (6), wash it with deionized water and anhydrous ethanol, and then dry it to obtain the product powder.

[0014] (8) The above-mentioned reactive powder is sintered to obtain the high specific surface area nano-cerium phosphate material.

[0015] In a preferred embodiment of the present invention, the modified corn starch is pregelatinized corn starch or oxidized corn starch. It is known in the art that pregelatinized corn starch is a modified corn starch produced through deep processing of native corn starch, which is obtained by extrusion, heating, expansion, followed by pulverization and sieving; oxidized corn starch is a modified corn starch obtained by reacting corn starch with an oxidizing agent in acidic, alkaline, or neutral media to oxidize the corn starch.

[0016] More preferably, the modified corn starch has an effective modified corn starch content of ≥99%, an ash content of ≤0.3%, a pH value of 5-8 for a 1-5% aqueous solution, a protein content of ≤2%, an amylose content of ≤10%, and a molecular weight of 30,000-60,000.

[0017] In a preferred embodiment of the present invention, the phosphate includes at least one of sodium phosphate, potassium phosphate, sodium hydrogen phosphate, potassium hydrogen phosphate, sodium dihydrogen phosphate, and potassium dihydrogen phosphate.

[0018] More preferably, the phosphate is one or two of sodium phosphate, sodium hydrogen phosphate, potassium hydrogen phosphate, sodium dihydrogen phosphate, and potassium dihydrogen phosphate.

[0019] In a preferred embodiment of the present invention, the soluble cerium salt includes at least one of cerium chloride heptahydrate, anhydrous cerium chloride, cerium nitrate hexahydrate, and anhydrous cerium nitrate.

[0020] More preferably, the soluble cerium salt is one or two of cerium chloride heptahydrate, anhydrous cerium chloride, cerium nitrate hexahydrate, and anhydrous cerium nitrate.

[0021] In a preferred embodiment of the present invention, the mass ratio of the modified corn starch, phosphate and soluble cerium salt is 1.8-4.2:4.9-7.0:9.8-17.5.

[0022] In a preferred embodiment of the present invention, the conditions for the hydrothermal reaction are: 120°C for 4 hours; 150°C for 6 hours; and 200°C for 8 hours.

[0023] In a preferred embodiment of the present invention, the sintering temperature is 500-700°C and the time is 3-5 hours.

[0024] The beneficial effects of this invention are as follows: The modified corn starch in this invention has good water solubility, and the solution exhibits good suspension and stability after dissolving in water. This suspension stability provides a spatial carrier for the generation of nano-cerium phosphate. A network structure is formed through hydrogen bonding between the molecular weight chains of the modified corn starch, which can control the uniformity of cerium phosphate particle size. Different specific surface area values ​​of cerium phosphate can be controlled by adjusting the concentration of the modified corn starch. The modified corn starch can be removed through subsequent high-temperature sintering and washing, ultimately obtaining high-purity cerium phosphate nanoparticles. The nanoparticles have uniformity and high specific surface area, making them suitable for application in electrode materials, adsorbent materials, luminescent materials, polymer nanofillers, and other materials.

[0025] 2. The process of the present invention is simple, the conditions are controllable, and the cost is low. Attached Figure Description

[0026] Figure 1 This is a SEM image of the high specific surface area nano-cerium phosphate material obtained in Example 4 of the present invention.

[0027] Figure 2 This is a SEM image of the comparative nano-cerium phosphate material obtained in Comparative Example 1 of this invention. Detailed Implementation

[0028] The technical solution of the present invention will be further explained and described below with reference to specific embodiments and accompanying drawings.

[0029] Example 1

[0030] (1) Preparation of pregelatinized corn starch solution: Add 1.8g of pregelatinized corn starch to 100mL of deionized water, heat and stir at 45℃ for 16h, cool at room temperature after complete dissolution, filter and set aside.

[0031] (2) Preparation of sodium hydrogen phosphate solution: Under stirring conditions, 5.64 g of sodium hydrogen phosphate was added to 50 mL of deionized water, stirred at room temperature for 18 min, filtered, and set aside.

[0032] (3) Preparation of anhydrous cerium nitrate solution: Under stirring conditions, 13.04 g of anhydrous cerium nitrate was added to 50 mL of deionized water, stirred at room temperature for 26 min, filtered, and set aside.

[0033] (4) Under room temperature and stirring conditions, slowly add sodium hydrogen phosphate solution to pregelatinized corn starch solution. After the addition is complete, continue stirring for 3.5 hours and adjust the pH value of the solution with 10% dilute phosphoric acid to control the pH value at around 5.

[0034] (5) Under room temperature and stirring conditions, anhydrous cerium nitrate solution is slowly added dropwise to the material obtained in step (4). The addition time is controlled at 40 min. After the addition is completed, the reaction is stirred for 6.5 h.

[0035] (6) Hydrothermal reaction: The material obtained in step (5) is placed in a polytetrafluoroethylene tank with a stainless steel shell. Then, the tank is placed in a muffle furnace for hydrothermal reaction. The reaction conditions are: 120℃, 4h; 150℃, 6h; 200℃, 8h.

[0036] (7) Drying treatment: After the reaction is completed, the material obtained in step (6) is filtered, washed twice with 100mL deionized water + 100mL ethanol, and dried in a 70℃ forced-air oven for 12h to obtain the product powder.

[0037] (8) Sintering treatment: The above product powder is placed in a muffle furnace and subjected to sintering heat treatment at a temperature of 650°C for 4 hours to obtain the high specific surface area nano-cerium phosphate material.

[0038] The test results of the high specific surface area nano-cerium phosphate material obtained in this embodiment are shown in the table below:

[0039] Table 1

[0040] Serial Number Test Project Measured value 1 Average particle size / nm 135 2 <![CDATA[BET / m 2 ·g -1 ]]> 123.5

[0041] Example 2

[0042] (1) Preparation of pregelatinized corn starch solution: Add 2.2g of pregelatinized corn starch to 200mL of deionized water, heat and stir at 50℃ for 14h, and after it is completely dissolved, cool at room temperature, filter and set aside.

[0043] (2) Preparation of sodium phosphate solution: Under stirring conditions, 6.55g of sodium phosphate was added to 50mL of deionized water, stirred at room temperature for 22min, filtered, and set aside.

[0044] (3) Preparation of cerium chloride heptahydrate solution: Under stirring conditions, 14.90 g of cerium chloride heptahydrate was added to 50 mL of deionized water, stirred at room temperature for 14 min, filtered, and set aside.

[0045] (4) Under room temperature and stirring conditions, the sodium phosphate solution was slowly added dropwise to the pregelatinized corn starch solution. After the addition was completed, stirring was continued for 4 hours. The pH value of the solution was adjusted with 10% dilute phosphoric acid to control the pH value at around 4.

[0046] (5) Under room temperature and stirring conditions, the cerium chloride heptahydrate solution is slowly added dropwise to the material obtained in step (4). The addition time is controlled at 50 min. After the addition is completed, the reaction is stirred for 5.5 h.

[0047] (6) Hydrothermal reaction: The material obtained in step (5) is placed in a polytetrafluoroethylene tank with a stainless steel shell. Then, the tank is placed in a muffle furnace for hydrothermal reaction. The reaction conditions are: 120℃, 4h; 150℃, 6h; 200℃, 8h.

[0048] (7) Drying treatment: After the reaction is completed, the material obtained in step (6) is filtered, washed twice with 100mL deionized water + 100mL ethanol, and dried in a 70℃ forced-air oven for 12h to obtain the product powder.

[0049] (8) Sintering treatment: The above product powder is placed in a muffle furnace for sintering heat treatment. The sintering temperature is 550℃ and the sintering time is 4h to obtain the high specific surface area nano-cerium phosphate material.

[0050] The test results of the high specific surface area nano-cerium phosphate material obtained in this embodiment are shown in the table below:

[0051] Table 2

[0052]

[0053]

[0054] Example 3

[0055] (1) Preparation of oxidized corn starch solution: Add 2.6g of oxidized corn starch to 200mL of deionized water, heat and stir at 40℃ for 12h, and after complete dissolution, cool at room temperature, filter and set aside.

[0056] (2) Preparation of potassium dihydrogen phosphate solution: Under stirring conditions, 5.44 g of potassium dihydrogen phosphate was added to 50 mL of deionized water, stirred at room temperature for 10 min, filtered, and set aside.

[0057] (3) Preparation of cerium nitrate hexahydrate solution: Under stirring conditions, 17.36 g of cerium nitrate hexahydrate was added to 50 mL of deionized water, stirred at room temperature for 18 min, filtered, and set aside.

[0058] (4) Under room temperature and stirring conditions, potassium dihydrogen phosphate solution was slowly added dropwise to the oxidized corn starch solution. After the addition was completed, stirring was continued for 5 hours. The pH value of the solution was adjusted with 10% dilute phosphoric acid to control the pH value at around 6.

[0059] (5) Under room temperature and stirring conditions, the cerium nitrate hexahydrate solution was slowly added dropwise to the material obtained in step (4). The addition time was controlled at 45 min. After the addition was completed, the reaction was stirred for 7 h.

[0060] (6) Hydrothermal reaction: The material obtained in step (5) is placed in a polytetrafluoroethylene tank with a stainless steel shell. Then, the tank is placed in a muffle furnace for hydrothermal reaction. The reaction conditions are: 120℃, 4h; 150℃, 6h; 200℃, 8h.

[0061] (7) Drying treatment: After the reaction is completed, the material obtained in step (6) is filtered, washed twice with 100mL deionized water + 100mL ethanol, and dried in a 70℃ forced-air oven for 12h to obtain the product powder.

[0062] (8) Sintering treatment: The above product powder is placed in a muffle furnace and subjected to sintering heat treatment at a temperature of 500°C for 4 hours to obtain the high specific surface area nano-cerium phosphate material.

[0063] The test results of the high specific surface area nano-cerium phosphate material obtained in this embodiment are shown in the table below:

[0064] Table 3

[0065] Serial Number Test Project Measured value 1 Average particle size / nm 130 2 <![CDATA[BET / m 2 ·g -1 ]]> 123.6

[0066] Example 4

[0067] (1) Preparation of pregelatinized corn starch solution: Add 3.0g of pregelatinized corn starch to 200mL of deionized water, heat and stir at 55℃ for 18h, and after it is completely dissolved, cool at room temperature, filter and set aside.

[0068] (2) Preparation of a mixed solution of sodium hydrogen phosphate and sodium dihydrogen phosphate: Under stirring conditions, 2.52 g of sodium hydrogen phosphate and 2.40 g of sodium dihydrogen phosphate were added to 50 mL of deionized water, stirred at room temperature for 26 min, filtered, and set aside.

[0069] (3) Preparation of cerium chloride solution: Under stirring conditions, 9.85g of cerium chloride was added to 50mL of deionized water, stirred at room temperature for 30min, filtered, and set aside.

[0070] (4) Under room temperature and stirring conditions, the mixed solution of sodium hydrogen phosphate and sodium dihydrogen phosphate was slowly added dropwise to the pregelatinized corn starch solution. After the addition was completed, stirring was continued for 4.5 hours. The pH value of the solution was adjusted with 10% dilute phosphoric acid to control the pH value at around 4.

[0071] (5) Under room temperature and stirring conditions, slowly add cerium chloride solution to the material obtained in step (4) for 30 minutes. After the addition is completed, continue stirring for 8 hours.

[0072] (6) Hydrothermal reaction: The material obtained in step (5) is placed in a polytetrafluoroethylene tank with a stainless steel shell. Then, the tank is placed in a muffle furnace for hydrothermal reaction. The reaction conditions are: 120℃, 4h; 150℃, 6h; 200℃, 8h.

[0073] (7) Drying treatment: After the reaction is completed, the material obtained in step (6) is filtered, washed twice with 100mL deionized water + 100mL ethanol, and dried in a 70℃ forced-air oven for 12h to obtain the product powder.

[0074] (8) Sintering treatment: The above-mentioned product powder was placed in a muffle furnace for sintering heat treatment at a temperature of 600℃ for 4 hours, to obtain the following product powder: Figure 1 The high specific surface area nano-cerium phosphate material shown.

[0075] The test results of the high specific surface area nano-cerium phosphate material obtained in this embodiment are shown in the table below:

[0076] Table 4

[0077] Serial Number Test Project Measured value 1 Average particle size / nm 110 2 <![CDATA[BET / m 2 ·g -1 ]]> 155.2

[0078] Example 5

[0079] (1) Preparation of oxidized corn starch solution: Add 3.4g of oxidized corn starch to 200mL of deionized water, heat and stir at 50℃ for 22h, and after it is completely dissolved, cool at room temperature, filter and set aside.

[0080] (2) Preparation of potassium hydrogen phosphate solution: Under stirring conditions, 6.96 g of potassium hydrogen phosphate was added to 50 mL of deionized water, stirred at room temperature for 14 min, filtered, and set aside.

[0081] (3) Preparation of cerium chloride heptahydrate solution: Under stirring conditions, 14.90 g of cerium chloride heptahydrate was added to 50 mL of deionized water, stirred at room temperature for 10 min, filtered, and set aside.

[0082] (4) Under room temperature and stirring conditions, potassium hydrogen phosphate solution was slowly added dropwise to the oxidized corn starch solution. After the addition was completed, stirring was continued for 3 hours. The pH value of the solution was adjusted with 10% dilute phosphoric acid to control the pH value at around 6.

[0083] (5) Under room temperature and stirring conditions, the cerium chloride heptahydrate solution is slowly added dropwise to the material obtained in step (4). The addition time is controlled at 35 min. After the addition is completed, the reaction is stirred for 5.5 h.

[0084] (6) Hydrothermal reaction: The material obtained in step (5) is placed in a polytetrafluoroethylene tank with a stainless steel shell. Then, the tank is placed in a muffle furnace for hydrothermal reaction. The reaction conditions are: 120℃, 4h; 150℃, 6h; 200℃, 8h.

[0085] (7) Drying treatment: After the reaction is completed, the material obtained in step (6) is filtered, washed twice with 100mL deionized water + 100mL ethanol, and dried in a 70℃ forced-air oven for 12h to obtain the product powder.

[0086] (8) Sintering treatment: The above product powder is placed in a muffle furnace and subjected to sintering heat treatment at a temperature of 650°C for 4 hours to obtain the high specific surface area nano-cerium phosphate material.

[0087] The test results of the high specific surface area nano-cerium phosphate material obtained in this embodiment are shown in the table below:

[0088] Table 5

[0089] Serial Number Test Project Measured value 1 Average particle size / nm 142 2 <![CDATA[BET / m 2 ·g- 1 ]]> 114.8

[0090] Example 6

[0091] (1) Preparation of oxidized corn starch solution: Add 3.8g of oxidized corn starch to 200mL of deionized water, heat and stir at 45℃ for 24h, and after complete dissolution, cool at room temperature, filter and set aside.

[0092] (2) Preparation of potassium phosphate and sodium hydrogen phosphate mixed solution: Under stirring conditions, 4.24 g potassium phosphate and 2.40 g sodium hydrogen phosphate were added to 50 mL deionized water, stirred at room temperature for 30 min, filtered and set aside.

[0093] (3) Preparation of cerium nitrate hexahydrate solution: Under stirring conditions, 17.36 g of cerium nitrate hexahydrate was added to 50 mL of deionized water, stirred at room temperature for 22 min, filtered, and set aside.

[0094] (4) Under room temperature and stirring conditions, the mixed solution of potassium phosphate and sodium hydrogen phosphate was slowly added dropwise to the oxidized corn starch solution. After the addition was completed, stirring was continued for 4 hours. The pH value of the solution was adjusted with 10% dilute phosphoric acid to control the pH value at around 5.

[0095] (5) Under room temperature and stirring conditions, the cerium nitrate hexahydrate solution is slowly added dropwise to the material obtained in step (4). The addition time is controlled at 45 min. After the addition is completed, the reaction is stirred for 5 h.

[0096] (6) Hydrothermal reaction: The material obtained in step (5) is placed in a polytetrafluoroethylene tank with a stainless steel shell. Then, the tank is placed in a muffle furnace for hydrothermal reaction. The reaction conditions are: 120℃, 4h; 150℃, 6h; 200℃, 8h.

[0097] (7) Drying treatment: After the reaction is completed, the material obtained in step (6) is filtered, washed twice with 100mL deionized water + 100mL ethanol, and dried in a 70℃ forced-air oven for 12h to obtain the product powder.

[0098] (8) Sintering treatment: The above product powder is placed in a muffle furnace and subjected to sintering heat treatment at a temperature of 500°C for 4 hours to obtain the high specific surface area nano-cerium phosphate material.

[0099] The test results of the high specific surface area nano-cerium phosphate material obtained in this embodiment are shown in the table below:

[0100] Table 6

[0101] Serial Number Test Project Measured value 1 Average particle size / nm 127 2 <![CDATA[BET / m 2 ·g -1 ]]> 121.6

[0102] Example 7

[0103] (1) Preparation of pregelatinized corn starch solution: Add 4.2g of pregelatinized corn starch to 200mL of deionized water, heat and stir at 55℃ for 20h, and after it is completely dissolved, cool at room temperature, filter and set aside.

[0104] (2) Preparation of sodium hydrogen phosphate solution: Under stirring conditions, 5.64 g of sodium hydrogen phosphate was added to 50 mL of deionized water, stirred at room temperature for 26 min, filtered, and set aside.

[0105] (3) Preparation of a mixed solution of cerium chloride heptahydrate and cerium nitrate hexahydrate: Under stirring conditions, 7.45 g of cerium chloride heptahydrate and 8.68 g of cerium nitrate hexahydrate were added to 50 mL of deionized water, stirred at room temperature for 18 min, filtered, and set aside.

[0106] (4) Under room temperature and stirring conditions, slowly add sodium hydrogen phosphate solution to pregelatinized corn starch solution. After the addition is complete, continue stirring for 4.5 hours and adjust the pH value of the solution with 10% dilute phosphoric acid to control the pH value at around 5.

[0107] (5) Under room temperature and stirring conditions, the mixed solution of cerium chloride heptahydrate and cerium nitrate hexahydrate is slowly added dropwise to the material obtained in step (4). The addition time is controlled at 35 min. After the addition is completed, the reaction is stirred for 6 h.

[0108] (6) Hydrothermal reaction: The material obtained in step (5) is placed in a polytetrafluoroethylene tank with a stainless steel shell. Then, the tank is placed in a muffle furnace for hydrothermal reaction. The reaction conditions are: 120℃, 4h; 150℃, 6h; 200℃, 8h.

[0109] (7) Drying treatment: After the reaction is completed, the material obtained in step (6) is filtered, washed twice with 100mL deionized water + 100mL ethanol, and dried in a 70℃ forced-air oven for 12h to obtain the product powder.

[0110] (8) Sintering treatment: The above product powder is placed in a muffle furnace and subjected to sintering heat treatment at a temperature of 700°C for 4 hours to obtain the high specific surface area nano-cerium phosphate material.

[0111] The test results of the high specific surface area nano-cerium phosphate material obtained in this embodiment are shown in the table below:

[0112] Table 7

[0113] Serial Number Test Project Measured value 1 Average particle size / nm 151 2 <![CDATA[BET / m 2 ·g -1 ]]> 114.4

[0114] Comparative Example 1

[0115] (1) Add 0g of pregelatinized corn starch to 200mL of deionized water, heat and stir at 55℃ for 18h, and after it is completely dissolved, cool at room temperature, filter and set aside.

[0116] (2) Preparation of a mixed solution of sodium hydrogen phosphate and sodium dihydrogen phosphate: Under stirring conditions, 2.52 g of sodium hydrogen phosphate and 2.40 g of sodium dihydrogen phosphate were added to 50 mL of deionized water, stirred at room temperature for 26 min, filtered, and set aside.

[0117] (3) Preparation of cerium chloride solution: Under stirring conditions, 9.85g of cerium chloride was added to 50mL of deionized water, stirred at room temperature for 30min, filtered, and set aside.

[0118] (4) Under room temperature and stirring conditions, the mixed solution of sodium hydrogen phosphate and sodium dihydrogen phosphate is slowly added dropwise to the material obtained in step (1). After the addition is completed, stirring is continued for 4.5 hours, and the pH value of the solution is adjusted with 10% dilute phosphoric acid to control the pH value at around 4.

[0119] (5) Under room temperature and stirring conditions, slowly add cerium chloride solution to the material obtained in step (4) for 30 minutes. After the addition is completed, continue stirring for 8 hours.

[0120] (6) Hydrothermal reaction: The material obtained in step (5) is placed in a polytetrafluoroethylene tank with a stainless steel shell. Then, the tank is placed in a muffle furnace for hydrothermal reaction. The reaction conditions are: 120℃, 4h; 150℃, 6h; 200℃, 8h.

[0121] (7) Drying treatment: After the reaction is completed, the material obtained in step (6) is filtered, washed twice with 100mL deionized water + 100mL ethanol, and dried in a 70℃ forced-air oven for 12h to obtain the product powder.

[0122] (8) Sintering treatment: The above-mentioned product powder was placed in a muffle furnace for sintering heat treatment at a temperature of 600℃ for 4 hours, to obtain the following product powder: Figure 2 The comparison shows cerium phosphate nanomaterials.

[0123] The test results of the comparative nano-cerium phosphate material obtained in this comparative example are shown in the table below:

[0124] Table 8

[0125] Serial Number Test Project Measured value 1 Average particle size / nm 254 2 <![CDATA[BET / m 2 ·g -1 ]]> 89.7

[0126] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A method for preparing a high specific surface area nano-cerium phosphate material, characterized in that: Includes the following steps: (1) Mix the modified corn starch with deionized water, heat and stir to dissolve, cool to room temperature and filter to obtain a modified corn starch solution; the modified corn starch is pregelatinized corn starch or oxidized corn starch; (2) Mix phosphate with deionized water, stir to dissolve at room temperature, and then filter to obtain a phosphate solution; (3) Mix soluble cerium salt with deionized water, stir to dissolve at room temperature, and then filter to obtain a cerium salt solution; The mass ratio of modified corn starch, phosphate, and soluble cerium salt is 1.8-4.2: 4.9-7.0: 9.8-17.

5. (4) At room temperature, while stirring, slowly add the above phosphate solution to the above modified corn starch solution. After the addition is complete, continue stirring for 3-5 hours and adjust the pH to 4-6 with phosphate solution. (5) At room temperature, while stirring, add the above cerium salt solution dropwise to the material obtained in step (4). The dropwise addition time is controlled at 30-50 min. After the dropwise addition is completed, continue stirring and reacting for 5-8 h. (6) The material obtained in step (5) is subjected to a hydrothermal reaction. The conditions for the hydrothermal reaction are: 115-125℃, 3-5h; 145-155℃, 5-7h; 195-205℃, 7-9h. (7) After filtering the material obtained in step (6), wash it with deionized water and anhydrous ethanol, and then dry it to obtain the product powder. (8) The above product powder is sintered to obtain the high specific surface area nano-cerium phosphate material.

2. The preparation method according to claim 1, characterized in that: The modified corn starch has an effective modified corn starch content of ≥99%, ash content of ≤0.3%, pH value of 1-5% aqueous solution of 5-8, protein content of ≤2%, amylose content of ≤10%, and molecular weight of 30000-60000.

3. The preparation method according to claim 1, characterized in that: The phosphate includes at least one of sodium phosphate, potassium phosphate, sodium hydrogen phosphate, potassium hydrogen phosphate, sodium dihydrogen phosphate, and potassium dihydrogen phosphate.

4. The preparation method according to claim 1, characterized in that: The soluble cerium salt includes at least one of cerium chloride heptahydrate, anhydrous cerium chloride, cerium nitrate hexahydrate, and anhydrous cerium nitrate.

5. The preparation method according to claim 1, characterized in that: The conditions for the hydrothermal reaction are: 120℃, 4h; 150℃, 6h; 200℃, 8h.

6. The preparation method according to claim 1, characterized in that: The sintering temperature is 500-700℃ and the time is 3-5h.

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