Preparation method of nano cerium dioxide particles

Abstract

The invention discloses a preparation method of nano cerium dioxide particles, and the preparation method of the nano cerium dioxide particles comprises the following steps: dissolving cerium nitrate hexahydrate in pure water to obtain a cerium nitrate solution; dissolving sodium hydroxide in pure water to obtain a sodium hydroxide solution; adding the cerium nitrate solution into kerosene, then adding span 80 and isopropanol, and stirring to obtain an emulsion; adding the sodium hydroxide solution into the emulsion, and stirring until precipitate appears; and filtering, washing and drying the precipitate, and carrying out annealing treatment in a muffle furnace to prepare the nano cerium dioxide particles. According to the preparation method of the small-particle-size nano cerium dioxide particles, a water-in-oil type reversed-phase microemulsion method is used, the morphology and the particle size of the particles can be effectively regulated and controlled, agglomeration is inhibited, the small-particle-size nano cerium dioxide particles which are uniform in appearance, spherical and uniform in particle size are obtained, and the particle size of the small-particle-size nano cerium dioxide particles reaches 30-50 nm.

Description

Technical Field

[0001] The present invention relates to the technical field of nanomaterials, and in particular to a method for preparing nano cerium dioxide particles. Background Art

[0002] Ceria, due to its unique physical and chemical properties, has been a major scientific research topic in recent years. Currently, ceria is widely used in waste gas treatment, polishing fluids, and gas sensors. Nanoceria particles, due to their large surface area and high chemical activity, often exhibit superior performance compared to their larger counterparts. Because the shape, size, and size distribution of nanoceria particles significantly influence their performance, research into the preparation of nanoceria particles with controllable coarse particle size is of paramount importance.

[0003] In previous studies, nano-cerium dioxide was mostly prepared by co-precipitation, hydrothermal, combustion and other methods. However, these methods have stringent requirements on reaction conditions, and have the defects of difficulty in controlling particle size and easy introduction of impurities, which limits the commercial application of nano-cerium dioxide. Summary of the Invention

[0004] The main purpose of the present invention is to provide a method for preparing nano-cerium dioxide particles, which is simple to operate and has controllable particle size.

[0005] To achieve the above object, the present invention provides a method for preparing nano-cerium dioxide particles, which comprises the following steps:

[0006] dissolving cerium nitrate hexahydrate in pure water to obtain a cerium nitrate solution;

[0007] Dissolve sodium hydroxide in pure water to obtain a sodium hydroxide solution;

[0008] The cerium nitrate solution is added to kerosene, and then Span 80 and isopropyl alcohol are added, and stirred to obtain an emulsion. The sodium hydroxide solution is then added to the emulsion, and stirring is continued until a precipitate appears.

[0009] The precipitate is filtered, washed, dried, and then annealed in a muffle furnace to obtain nano-cerium dioxide particles.

[0010] Optionally, in the step of dissolving cerium nitrate hexahydrate in pure water to obtain a cerium nitrate solution:

[0011] The concentration of cerium nitrate in the cerium nitrate solution is 1-2 mol / L.

[0012] Optionally, in the step of dissolving sodium hydroxide in pure water to obtain a sodium hydroxide solution:

[0013] The concentration of sodium hydroxide in the sodium hydroxide solution is 5-9 mol / L.

[0014] Optionally, in the step of adding the cerium nitrate solution to kerosene, then adding Span 80 and isopropyl alcohol, and stirring to obtain an emulsion:

[0015] The volume ratio of the cerium nitrate solution to kerosene is 1:15-18;

[0016] The mass ratio of the kerosene, Span 80 and isopropyl alcohol is 150-220:12-14:7.

[0017] Optionally, in the step of adding the cerium nitrate solution to kerosene, then adding Span 80 and isopropyl alcohol, and stirring to obtain an emulsion:

[0018] The stirring speed is 300-500 rpm, and the stirring time is 0.5-2 h.

[0019] Optionally, the cerium nitrate solution is added to kerosene, and then Span 80 and isopropyl alcohol are added, and stirred to obtain an emulsion, and then the sodium hydroxide solution is added to the emulsion, and stirring is continued until a precipitate appears:

[0020] The volume ratio of the sodium hydroxide solution to the cerium nitrate solution is 1 to 1.5:2;

[0021] The stirring speed of the continued stirring is 400-800 rpm, and the stirring time is 4-10 hours.

[0022] Optionally, in the step of filtering, washing, and drying the precipitate, and then annealing the precipitate in a muffle furnace to prepare nano-cerium dioxide particles:

[0023] The filtering method includes vacuum filtration.

[0024] Optionally, in the step of filtering, washing, and drying the precipitate, and then annealing the precipitate in a muffle furnace to obtain nano-cerium dioxide particles, the washing comprises:

[0025] First wash with isopropyl alcohol 2 to 3 times, then wash with pure water 2 to 3 times.

[0026] Optionally, in the step of filtering, washing, and drying the precipitate, and then annealing the precipitate in a muffle furnace to prepare nano-cerium dioxide particles:

[0027] The drying temperature is 60-80° C. and the drying time is 20-30 hours.

[0028] Optionally, in the step of filtering, washing, and drying the precipitate, and then annealing the precipitate in a muffle furnace to prepare nano-cerium dioxide particles:

[0029] The annealing temperature of the annealing treatment is 700-800° C., and the annealing time is 0.5-5 hours.

[0030] The present invention provides a preparation method of small-size nano-cerium dioxide particles. The method uses cerium nitrate hexahydrate as a raw material and employs a water-in-oil reverse microemulsion method, so that an aqueous phase is dispersed in a continuous oil phase in the form of nano-scale droplets. This limits the growth range of the nano-particles, effectively controls the morphology and particle size of the particles, and inhibits agglomeration, thereby obtaining small-size nano-cerium dioxide particles with a uniform spherical shape and uniform particle size, wherein the particle size reaches 30 to 50 nm. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] 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 ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic flow chart of an embodiment of a method for preparing nano-cerium dioxide particles provided by the present invention;

[0033] Figure 2 and Figure 3 SEM images of nano-cerium dioxide particles prepared in some embodiments of the present invention;

[0034] Figure 4 and Figure 5 XRD patterns of nano-cerium dioxide particles prepared in some embodiments of the present invention.

[0035] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. Where the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased commercially. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but must be based on the ability of ordinary technicians in this field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that the combination of such technical solutions does not exist and is not within the scope of protection required by the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0037] To prepare nano-cerium dioxide particles with controllable particle size, the inventors discovered that the microemulsion method uses surfactants to separate two immiscible solvents into tiny droplets whose size can be controlled within the nanometer range. The reactants react within these droplets to form solid-phase particles. The advantage of the microemulsion method is that the droplet size can be controlled by varying the ratio of the two solutions, thereby controlling the particle size and shape of the reaction product. Based on these studies, the inventors proposed a method for preparing nano-cerium dioxide particles using the microemulsion method. For details, see [ 1 ]. Figure 1 As shown, in the present invention, the preparation method of the nano cerium dioxide particles comprises the following steps:

[0038] Step S10, dissolving cerium nitrate hexahydrate in pure water to obtain a cerium nitrate solution;

[0039] Step S20, dissolving sodium hydroxide in pure water to obtain a sodium hydroxide solution;

[0040] Step S30, adding the cerium nitrate solution to kerosene, then adding Span 80 and isopropyl alcohol, stirring to obtain an emulsion, then adding the sodium hydroxide solution to the emulsion, stirring until a precipitate appears;

[0041] Step S40: filtering, washing, and drying the precipitate, and then annealing the precipitate in a muffle furnace to obtain nano-cerium dioxide particles.

[0042] The method uses cerium nitrate hexahydrate as a raw material, prepares a cerium nitrate solution and a sodium hydroxide solution respectively, then adds the cerium nitrate solution into kerosene, adds Span 80 and isopropyl alcohol, and stirs evenly to obtain an emulsion, then adds the sodium hydroxide solution into the emulsion, stirs until a large amount of precipitates appear in the system, filters the precipitates, washes and dries to obtain cerium hydroxide solid, and finally places the cerium hydroxide solid in a muffle furnace for annealing treatment to prepare spherical nano-cerium dioxide particles.

[0043] The present invention provides a preparation method of small-size nano-cerium dioxide particles. The method uses cerium nitrate hexahydrate as a raw material and employs a water-in-oil reverse microemulsion method, so that an aqueous phase is dispersed in a continuous oil phase in the form of nano-scale droplets. This limits the growth range of the nano-particles, effectively controls the morphology and particle size of the particles, and inhibits agglomeration, thereby obtaining small-size nano-cerium dioxide particles with a uniform spherical shape and uniform particle size, wherein the particle size reaches 30 to 50 nm.

[0044] It should be noted that the present invention does not strictly limit the order between step S10 and step S20. Step S10 can be performed first and step S20 can be performed later, or step S20 can be performed first and step S10 can be performed later, or step S10 and step S20 can be performed simultaneously. It is only necessary to prepare the cerium nitrate solution and the sodium hydroxide solution separately before step S30.

[0045] In some embodiments of the present invention, in step S10: the concentration of cerium nitrate in the cerium nitrate solution is 1 to 2 mol / L, for example, it can be 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L or 2.0 mol / L, etc.

[0046] In some embodiments of the present invention, in step S20: the concentration of sodium hydroxide in the sodium hydroxide solution is 5 to 9 mol / L, for example, it can be 5 mol / L, 5.5 mol / L, 6 mol / L, 6.5 mol / L, 7 mol / L, 7.5 mol / L, 8 mol / L, 8.5 mol / L or 9 mol / L.

[0047] In some embodiments of the present invention, in step S30, the volume ratio of the cerium nitrate solution to kerosene is 1:15-18, for example, 1:15, 1:16, 1:17, or 1:18, and preferably 1:16; the mass ratio of kerosene, Span 80, and isopropyl alcohol is 150-220:12-14:7, for example, 150:14:7, 170:14:7, 180:14:7, 200:14:7, 200:12:7, 220:14:7, and preferably 200:14:7.

[0048] In some embodiments of the present invention, in step S30: the stirring speed of the stirring is 300-500 rpm, for example, it can be 300 rpm, 350 rpm, 400 rpm, 450 rpm or 500 rpm, etc., and the stirring time of the stirring is 0.5-2 h, for example, it can be 0.5 h, 1 h, 1.5 h or 2 h, etc.

[0049] In some embodiments of the present invention, in step S40: the volume ratio of the sodium hydroxide solution to the cerium nitrate solution is 1 to 1.5:1, for example, it can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4 or 1:1.5, etc.; the stirring speed of the continued stirring is 400 to 800 rpm, for example, it can be 400 rpm, 500 rpm, 600 rpm, 700 rpm or 800 rpm, etc., and the stirring time of the continued stirring is 4 to 10 h, for example, it can be 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h, etc.

[0050] In some embodiments of the present invention, in step S50, the filtration method includes vacuum filtration. The vacuum filtration method has the advantages of high water removal rate and simple operation.

[0051] In some embodiments of the present invention, the washing in step S50 is carried out by sequentially washing with isopropyl alcohol and pure water. Specifically, the washing can be carried out in the following manner: first washing with isopropyl alcohol for 2 to 3 times, and then washing with pure water for 2 to 3 times.

[0052] In some embodiments of the present invention, the drying method in step S50 is preferably oven drying, which is simpler and faster. Furthermore, the drying temperature is 60-80°C, for example, 60°C, 65°C, 70°C, 75°C, or 80°C, and the drying time is 20-30 hours, for example, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours, or 30 hours.

[0053] In some embodiments of the present invention, in step S50: the annealing temperature of the annealing treatment is 700-800°C, for example, it can be set to 700°C, 710°C, 720°C, 730°C, 740°C, 750°C, 760°C, 770°C, 780°C, 790°C or 800°C, etc., and the annealing time of the annealing treatment is 0.5-5h, for example, it can be 0.5h, 1h, 2h, 3h, 4h or 5h, etc.

[0054] The technical solutions of the present invention are further described in detail below in conjunction with specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0055] Example 1

[0056] (1) Dissolve 4.34 g of cerium nitrate hexahydrate in 10 mL of pure water and stir to dissolve to obtain a cerium nitrate aqueous solution with a concentration of 1 mol / L.

[0057] (2) Dissolve 3.2 g of sodium hydroxide in 10 mL of pure water and stir to dissolve to obtain a sodium hydroxide solution with a concentration of 8 mol / L.

[0058] (3) 10 mL of the cerium nitrate aqueous solution obtained in step (1) was added to 200 mL of kerosene, and then 14 g of Span 80 and 7 g of isopropanol were added, and the mixture was stirred at 300 rpm for 1 h to obtain an emulsion.

[0059] (4) 10 mL of the sodium hydroxide solution prepared in step (2) was added to the emulsion prepared in step (3), and stirring was continued at 400 rpm for 4 h. A large amount of precipitate appeared in the system.

[0060] (5) Using a vacuum filtration device to filter the precipitate produced in step (4), the product obtained by vacuum filtration was first washed twice with isopropyl alcohol, then washed twice with pure water, and then placed in an oven for drying at a temperature of 70° C. for 24 h to obtain cerium hydroxide solid.

[0061] (6) The cerium hydroxide solid obtained in step (5) is placed in a muffle furnace and annealed at 700° C. for 0.5 h to obtain spherical nano-cerium dioxide particles.

[0062] Example 2

[0063] (1) Dissolve 86.8 g of cerium nitrate hexahydrate in 100 mL of pure water and stir to dissolve to obtain a cerium nitrate aqueous solution with a concentration of 2 mol / L.

[0064] (2) Dissolve 36 g of sodium hydroxide in 100 mL of pure water and stir to dissolve to obtain a sodium hydroxide solution with a concentration of 9 mol / L.

[0065] (3) 100 mL of the cerium nitrate aqueous solution obtained in step (1) was added to 2000 mL of kerosene, and then 140 g of Span 80 and 70 g of isopropyl alcohol were added, and the mixture was stirred at a speed of 500 rpm for 1 h to obtain an emulsion.

[0066] (4) 10 mL of the sodium hydroxide solution prepared in step (2) was added to the emulsion prepared in step (3), and the mixture was stirred at 800 rpm for 10 h. A large amount of precipitate appeared in the system.

[0067] (5) Using a vacuum filtration device to filter the precipitate produced in step (4), the product obtained by vacuum filtration was first washed with isopropyl alcohol three times, then washed with pure water three times, and then placed in an oven for drying at a temperature of 75° C. for 24 h to obtain cerium hydroxide solid.

[0068] (6) The cerium hydroxide solid obtained in step (5) is placed in a muffle furnace and annealed at 700° C. for 3 h to obtain spherical nano-cerium dioxide particles.

[0069] Example 3

[0070] (1) Dissolve 6.51 g of cerium nitrate hexahydrate in 10 mL of pure water and stir to dissolve to obtain a cerium nitrate aqueous solution with a concentration of 1.5 mol / L.

[0071] (2) Dissolve 2.8 g of sodium hydroxide in 10 mL of pure water and stir to dissolve to obtain a sodium hydroxide solution with a concentration of 7 mol / L.

[0072] (3) 10 mL of the cerium nitrate aqueous solution obtained in step (1) was added to 150 mL of kerosene, and then 14 g of Span 80 and 7 g of isopropanol were added, and the mixture was stirred at 400 rpm for 2 h to obtain an emulsion.

[0073] (4) 10 mL of the sodium hydroxide solution prepared in step (2) was added to the emulsion prepared in step (3), and the mixture was stirred at 500 rpm for 6 h. A large amount of precipitate appeared in the system.

[0074] (5) Using a vacuum filtration device to filter the precipitate produced in step (4), the product obtained by vacuum filtration was first washed twice with isopropyl alcohol, then washed three times with pure water, and then placed in an oven for drying at a temperature of 65° C. for 27 h to obtain cerium hydroxide solid.

[0075] (6) The cerium hydroxide solid obtained in step (5) is placed in a muffle furnace and annealed at 700° C. for 5 h to obtain spherical nano-cerium dioxide particles.

[0076] Example 4

[0077] (1) Dissolve 4.34 g of cerium nitrate hexahydrate in 10 mL of pure water, and stir to dissolve to obtain a cerium nitrate aqueous solution with a concentration of 1 to 2 mol / L.

[0078] (2) Dissolve 2.4 g of sodium hydroxide in 10 mL of pure water and stir to dissolve to obtain a sodium hydroxide solution with a concentration of 6 mol / L.

[0079] (3) 10 mL of the cerium nitrate aqueous solution obtained in step (1) was added to 170 mL of kerosene, and then 14 g of Span 80 and 7 g of isopropyl alcohol were added, and the mixture was stirred at a speed of 350 rpm for 1.5 h to obtain an emulsion.

[0080] (4) 10 mL of the sodium hydroxide solution prepared in step (2) was added to the emulsion prepared in step (3), and stirring was continued at a speed of 700 rpm for 8 h. A large amount of precipitate appeared in the system.

[0081] (5) Using a vacuum filtration device to filter the precipitate produced in step (4), the product obtained by vacuum filtration was first washed with isopropyl alcohol three times, then washed with pure water twice, and then placed in an oven for drying at a temperature of 60° C. for 30 h to obtain cerium hydroxide solid.

[0082] (6) The cerium hydroxide solid obtained in step (5) is placed in a muffle furnace and annealed at 750° C. for 2 h to obtain spherical nano-cerium dioxide particles.

[0083] Example 5

[0084] (1) Dissolve 4.34 g of cerium nitrate hexahydrate in 10 mL of pure water, and stir to dissolve to obtain a cerium nitrate aqueous solution with a concentration of 1 to 2 mol / L.

[0085] (2) Dissolve 2.0 g of sodium hydroxide in 10 mL of pure water and stir to dissolve to obtain a sodium hydroxide solution with a concentration of 5 mol / L.

[0086] (3) 10 mL of the cerium nitrate aqueous solution obtained in step (1) was added to 180 mL of kerosene, and then 14 g of Span 80 and 7 g of isopropyl alcohol were added, and the mixture was stirred at 450 rpm for 1 h to obtain an emulsion.

[0087] (4) 10 mL of the sodium hydroxide solution prepared in step (2) was added to the emulsion prepared in step (3), and stirring was continued at a speed of 600 rpm for 5 h. A large amount of precipitate appeared in the system.

[0088] (5) Using a vacuum filtration device to filter the precipitate produced in step (4), the product obtained by vacuum filtration was first washed twice with isopropyl alcohol, then washed three times with pure water, and then placed in an oven for drying at a temperature of 80° C. for 20 h to obtain cerium hydroxide solid.

[0089] (6) The cerium hydroxide solid obtained in step (5) is placed in a muffle furnace and annealed at 800° C. for 4 h to obtain spherical nano-cerium dioxide particles.

[0090] Since the SEM image results of each embodiment are similar, this paper only uses the SEM images of the nano-spherical cerium dioxide particles prepared in some embodiments as examples for analysis. Figure 2 and Figure 3 Shown are SEM images of the nano-spherical cerium dioxide particles prepared in Example 1 and Example 2, respectively.

[0091] Depend on Figure 2 and Figure 3 It can be seen that the nano-cerium dioxide particles prepared by the method provided by the present invention have a spherical structure, are substantially free of agglomeration, have a regular morphology, and are uniform in particle size. The particle size of the nanospheres reaches 30 to 50 nm.

[0092] Since the XRD pattern results of each embodiment are similar, this paper only uses the XRD of nano-spherical cerium dioxide particles prepared in some embodiments as an example for analysis. Figure 4 and Figure 5 Shown are the XRD patterns of the nano-spherical cerium dioxide particles prepared in Example 1 and Example 2, respectively.

[0093] according to Figure 4 and Figure 5 The XRD data, combined with the Scherrer formula, can be used to calculate the corresponding nanosphere particle size to be 30-50 nm.

[0094] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of the present invention.

Claims

1. A method for preparing nano-cerium dioxide particles, characterized in that: The preparation method of the nano-cerium dioxide particles comprises the following steps: dissolving cerium nitrate hexahydrate in pure water to obtain a cerium nitrate solution; Dissolve sodium hydroxide in pure water to obtain a sodium hydroxide solution; The cerium nitrate solution is added to kerosene, and then Span 80 and isopropyl alcohol are added, and stirred to obtain an emulsion. The sodium hydroxide solution is then added to the emulsion, and stirring is continued until a precipitate appears. The precipitate is filtered, washed, dried, and then annealed in a muffle furnace to obtain nano-cerium dioxide particles.

2. The method for preparing nano-cerium dioxide particles according to claim 1, wherein: In the step of dissolving cerium nitrate hexahydrate in pure water to obtain a cerium nitrate solution: The concentration of cerium nitrate in the cerium nitrate solution is 1-2 mol / L.

3. The method for preparing nano-cerium dioxide particles according to claim 1, wherein: Dissolve sodium hydroxide in pure water to obtain a sodium hydroxide solution: The concentration of sodium hydroxide in the sodium hydroxide solution is 5-9 mol / L.

4. The method for preparing nano-cerium dioxide particles according to claim 1, wherein: In the step of adding the cerium nitrate solution to kerosene, then adding Span 80 and isopropyl alcohol, and stirring to obtain an emulsion: The volume ratio of the cerium nitrate solution to kerosene is 1:15-18; The mass ratio of the kerosene, Span 80 and isopropyl alcohol is 150-220:12-14:

7.

5. The method for preparing nano-cerium dioxide particles according to claim 1, wherein: In the step of adding the cerium nitrate solution to kerosene, then adding Span 80 and isopropyl alcohol, and stirring to obtain an emulsion: The stirring speed is 300-500 rpm, and the stirring time is 0.5-2 h.

6. The method for preparing nano-cerium dioxide particles according to claim 1, wherein: The cerium nitrate solution is added to kerosene, and then Span 80 and isopropyl alcohol are added and stirred to obtain an emulsion. The sodium hydroxide solution is then added to the emulsion and stirring is continued until a precipitate appears. The volume ratio of the sodium hydroxide solution to the cerium nitrate solution is 1 to 1.5:1; The stirring speed of the continued stirring is 400-800 rpm, and the stirring time is 4-10 hours.

7. The method for preparing nano-cerium dioxide particles according to claim 1, wherein: The precipitate is filtered, washed, dried, and then annealed in a muffle furnace to obtain nano-cerium dioxide particles: The filtering method includes vacuum filtration.

8. The method for preparing nano-cerium dioxide particles according to claim 1, wherein: In the step of filtering, washing, and drying the precipitate, and then annealing the precipitate in a muffle furnace to obtain nano-cerium dioxide particles, the washing comprises: First wash with isopropyl alcohol 2 to 3 times, then wash with pure water 2 to 3 times.

9. The method for preparing nano-cerium dioxide particles according to claim 1, wherein: The precipitate is filtered, washed, dried, and then annealed in a muffle furnace to obtain nano-cerium dioxide particles: The drying temperature is 60-80° C. and the drying time is 20-30 hours.

10. The method for preparing nano-cerium dioxide particles according to claim 1, wherein: The precipitate is filtered, washed, dried, and then annealed in a muffle furnace to obtain nano-cerium dioxide particles: The annealing temperature of the annealing treatment is 700-800° C., and the annealing time is 0.5-5 hours.

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