A hydrophilic cerium oxide nanosphere, its preparation method and application

Abstract

This invention belongs to the field of cerium oxide nanomaterials technology, and relates to a hydrophilic cerium oxide nanosphere, its preparation method, and its applications. The hydrophilic cerium oxide nanospheres have a spherical structure with an average particle size of 50-500 nm, and are made of sulfur-doped cerium oxide; the water contact angle of the hydrophilic cerium oxide nanospheres is ≤30°. The preparation method involves mixing cerium salt with an alcohol compound and a hydrophilic modifier, followed by a solvothermal reaction to obtain a cerium-based precursor; under an oxidizing atmosphere, the cerium-based precursor is heated to 500-800℃ for calcination and pyrolysis. The hydrophilic cerium oxide nanospheres provided by this invention incorporate elements such as sulfur, changing the inert surface of cerium oxide to a hydrophilic surface, fundamentally altering the hydrophilic properties of cerium oxide, which is beneficial for improving its dispersion stability in water or alcohol, and shows broad application prospects in catalysis, polishing, luminescence, and ultraviolet absorption.

Description

Technical Field

[0001] This invention belongs to the field of cerium oxide nanomaterials technology, and relates to a hydrophilic cerium oxide nanosphere, its preparation method and application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Cerium oxide (CeO2) is a rare earth oxide material with excellent oxygen storage and release capabilities, high catalytic activity, good UV shielding properties, and chemical stability. It is mainly used in automotive exhaust purification catalysts, polishing powders for precision glass / optical components, glass decolorizing and clarifying agents, solid oxide fuel cell electrolytes, and UV absorbing materials. Cerium oxide is generally synthesized using high-temperature hydrothermal or calcination methods. However, the cerium oxide nanoparticles obtained by these methods tend to aggregate and exhibit poor dispersion stability in water or alcohol, limiting the applications of cerium oxide.

[0004] To improve the dispersion stability of cerium oxide in water or alcohol, hydrophilic polymers or surfactants can be used to hydrophilize cerium oxide. However, this treatment method can only improve the dispersion stability of cerium oxide in water or alcohol through physical modification or intermolecular forces. Not only are the operation steps cumbersome, but it also cannot fundamentally solve the intrinsic properties of cerium oxide, and has strong limitations. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a hydrophilic cerium oxide nanosphere, its preparation method, and its applications. The hydrophilic cerium oxide nanosphere provided by the present invention incorporates elements such as N and S, which transforms the inert surface of cerium oxide into a hydrophilic surface, fundamentally altering the hydrophilic properties of cerium oxide. This improves its dispersion stability in water or alcohol and demonstrates broad application prospects in fields such as catalysis, polishing, luminescence, and ultraviolet absorption.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] In a first aspect, there is a hydrophilic cerium oxide nanosphere, which has a spherical structure with an average particle size of 50~500 nm and is made of cerium oxide doped with sulfur; the water contact angle of the hydrophilic cerium oxide nanosphere is ≤30°.

[0008] The hydrophilic cerium oxide nanospheres provided by this invention are made of sulfur-doped cerium oxide. S has strong electronegativity and easily forms hydrogen bonds with water or alcohol. In addition, doping causes defect structures to be generated in the cerium oxide nanospheres, so that the doped cerium oxide carries a certain charge. Through the synergistic effect of the above, the hydrophilicity of cerium oxide is increased, and its dispersion stability in water or alcohol is also increased.

[0009] On the other hand, a method for preparing hydrophilic cerium oxide nanospheres includes the following steps:

[0010] A cerium salt is mixed with an alcohol compound and a hydrophilic modifier, and then subjected to a solvothermal reaction to obtain a cerium-based precursor; the hydrophilic modifier is one or more of aminobenzenesulfonic acid or its salt, taurine or its salt, N-acyltaurine or its salt, and polyaniline sulfonic acid or its salt.

[0011] The cerium-based precursor is obtained by calcining and pyrolyzing it at 500-800°C under an oxidizing atmosphere.

[0012] In the solvothermal reaction process, this invention adds alcohol compounds, which not only act as reducing agents to adjust the oxidation state of cerium, but also as structure directing agents to control particle size and morphology, and as complexing agents to stabilize metal ions and control the crystallization rate. Simultaneously, this invention introduces amino and sulfonic acid groups into the cerium-based precursor by adding sodium aminobenzenesulfonate. Then, through oxidative calcination and pyrolysis, sulfur is doped into cerium oxide, allowing hydrophilic elements (such as sulfur) to be incorporated without altering the cerium oxide crystal structure. The morphology is controlled to be a spherical structure with an average particle size of 50-500 nm, forming hydrophilic cerium oxide nanospheres with the characteristics described in the first aspect of this invention, thereby increasing the hydrophilicity of cerium oxide and its dispersion stability in water or alcohol.

[0013] Thirdly, the application of the above-mentioned hydrophilic cerium oxide nanospheres or the hydrophilic cerium oxide nanospheres obtained by the above preparation method in catalysis, polishing, luminescence or ultraviolet absorption.

[0014] The beneficial effects of this invention are as follows:

[0015] The hydrophilic cerium oxide nanospheres provided by this invention incorporate sulfur doping into cerium oxide. Due to the strong electronegativity of sulfur, it readily forms hydrogen bonds with water or alcohol. Furthermore, the defective structures created by the incorporation of sulfur enable cerium oxide to carry a certain charge. This not only increases the hydrophilicity of the cerium oxide nanospheres but also enhances the electrostatic repulsion between cerium oxide particles, thereby increasing their dispersibility in water or alcohol.

[0016] In the preparation of hydrophilic cerium oxide nanospheres, this invention introduces hydrophilic groups such as amino and sulfonic acid groups into the cerium-based precursor by adding sodium aminobenzenesulfonate in a solvothermal reaction. Then, through oxidative calcination and pyrolysis, sulfur is doped into the cerium oxide, increasing its hydrophilicity and consequently its dispersibility in water or alcohol. The preparation method of this invention is simple to operate and fundamentally alters the hydrophilicity and dispersibility of cerium oxide, making it suitable for a wide range of applications. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 This is a SEM image of the hydrophilic CeO2 prepared in Example 3 of the present invention;

[0019] Figure 2 The image shows the XRD pattern of the hydrophilic CeO2 prepared in Example 3 of this invention.

[0020] Figure 3 EDS energy spectrum of hydrophilic CeO2 prepared in Example 3 of the present invention. A is electron micrograph, B is Ce Lα1, C is OH Kα1, and D is SKα1.

[0021] Figure 4 The image shows the contact angle results of ordinary CeO2 (A) prepared in Comparative Example 1 and hydrophilic CeO2 (B) prepared in Example 3 of this invention.

[0022] Figure 5 Images of ordinary CeO2 (A) prepared in Comparative Example 1 and hydrophilic CeO2 (B) prepared in Example 3 after standing in water for one day. Detailed Implementation

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] Given that cerium oxide prepared by existing methods is prone to aggregation and has poor dispersion stability in water or alcohol, and that modification methods are difficult to fundamentally change the hydrophilicity of cerium oxide, this invention proposes a hydrophilic cerium oxide nanosphere, its preparation method, and its application.

[0026] In a typical embodiment of the present invention, a hydrophilic cerium oxide nanosphere is provided, which has a spherical structure with an average particle size of 50~500 nm and is made of cerium oxide doped with sulfur; the water contact angle of the hydrophilic cerium oxide nanosphere is ≤30°.

[0027] In some embodiments, the average particle size of the spherical structure is 100~300 nm, preferably 150~250 nm.

[0028] In some embodiments, the water contact angle of the hydrophilic cerium oxide nanospheres is 20~30°, preferably 24~26°.

[0029] Another embodiment of the present invention provides a method for preparing hydrophilic cerium oxide nanospheres, comprising the following steps:

[0030] A cerium salt is mixed with an alcohol compound and a hydrophilic modifier, and then subjected to a solvothermal reaction to obtain a cerium-based precursor; the hydrophilic modifier is one or more of aminobenzenesulfonic acid (which may be p-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, or o-aminobenzenesulfonic acid) or its salt, taurine or its salt, N-acyltaurine or its salt, and polyaniline sulfonic acid or its salt.

[0031] The cerium-based precursor is obtained by calcining and pyrolyzing it at 500-800°C under an oxidizing atmosphere.

[0032] The cerium salts mentioned in this invention refer to compounds whose cation is cerium ion, such as cerium nitrate, cerium sulfate, cerium chloride, cerium acetate, etc.

[0033] The alcohol compounds mentioned in this invention refer to compounds containing alcohol hydroxyl groups, such as methanol, ethanol, ethylene glycol, glycerol, etc. Among them, alcohol compounds such as ethylene glycol and glycerol containing at least two hydroxyl groups have better effects on morphology adjustment and crystallization rate adjustment.

[0034] In some embodiments, the molar ratio of cerium salt to hydrophilic modifier is 1.0~20.0:1, preferably 1.0~10.0:1, more preferably 4.0~9.0:1, and even more preferably 6.0~7.0:1. Studies have shown that a molar ratio of cerium salt to hydrophilic modifier of 6.0~7.0:1 results in better hydrophilicity.

[0035] In some embodiments, a precipitant is added to the solvothermal reaction system. Adding a precipitant adjusts the solution pH, promoting cerium salt precipitation and aging, and further facilitating the regulation of precursor morphology. The precipitant described in this invention is a compound that causes cerium salt to precipitate by adjusting the pH; it can be ammonia, hydroxides of alkali metals (Li, Na, K, etc., Group I metals), etc.

[0036] The solvothermal reaction described in this invention refers to a reaction carried out under closed conditions using a non-aqueous solvent, and heated to a pressure atmosphere higher than atmospheric pressure. In some embodiments, the temperature of the solvothermal reaction is 80~200℃. Specifically, the time of the solvothermal reaction is 6~20h. The solvothermal reaction is more effective under these conditions, especially when the temperature is 115~125℃.

[0037] In some embodiments, after the solvothermal reaction, the sample is washed and dried, and then subjected to calcination pyrolysis. This removes unreacted raw materials and completely removes the solvent adhering to the precursor, preventing excessively rapid temperature rise during calcination pyrolysis, which could lead to rapid solvent evaporation and affect the structure of the cerium oxide nanospheres.

[0038] Specifically, washing is performed using an ethanol-water solution. The washing effect is better with an ethanol-water solution. More specifically, the volume ratio of ethanol to water in the ethanol-water solution is 1:0.9~1.1.

[0039] Specifically, the drying temperature is 55~65℃, and the drying time is 10~14 h. This facilitates the complete removal of the solvent.

[0040] In some embodiments, the calcination and pyrolysis time is 5-10 h.

[0041] A third embodiment of the present invention provides an application of the above-described hydrophilic cerium oxide nanospheres or the hydrophilic cerium oxide nanospheres obtained by the above preparation method in catalysis, polishing, luminescence or ultraviolet absorption.

[0042] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0043] Example 1

[0044] A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps:

[0045] (1) Mix 2 ml of 25wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to solution A and mix well to obtain solution B.

[0046] (2) Dissolve 0.2 g of sodium p-aminobenzenesulfonate (SAS) in 5 ml of water to prepare SAS aqueous solution. Add the SAS aqueous solution to the B solution obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, transfer to a high-pressure reactor for reaction. The reaction temperature is 80 ℃ and the reaction time is 18 h.

[0047] (3) The material obtained in step (2) is centrifuged and the solid after separation is washed three times with an ethanol-water solution (ethanol to water volume ratio of 1:1), and then placed in a 60 ℃ oven for 12 h to dry for later use.

[0048] (4) Place the dried material from step (3) in a tube furnace and heat it to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres are obtained.

[0049] Example 2

[0050] A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps:

[0051] (1) Mix 2 ml of 25wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to solution A and mix well to obtain solution B.

[0052] (2) Dissolve 0.2 g of sodium p-aminobenzenesulfonate (SAS) in 5 ml of water to prepare SAS aqueous solution. Add the SAS aqueous solution to the B solution obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, transfer to a high-pressure reactor for reaction. The reaction temperature is 200 ℃ and the reaction time is 18 h.

[0053] (3) The material obtained in step (2) is centrifuged and the solid after separation is washed three times with an ethanol-water solution (ethanol to water volume ratio of 1:1), and then placed in a 60℃ oven for 12 h to dry for later use.

[0054] (4) Place the dried material from step (3) in a tube furnace and heat it to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres are obtained.

[0055] Example 3

[0056] A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps:

[0057] (1) Mix 2 ml of 25wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to solution A and mix well to obtain solution B.

[0058] (2) Dissolve 0.2 g of sodium p-aminobenzenesulfonate (SAS) in 5 ml of water to prepare SAS aqueous solution. Add the SAS aqueous solution to the B solution obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, transfer to a high-pressure reactor for reaction. The reaction temperature is 120 ℃ and the reaction time is 18 h.

[0059] (3) The material obtained in step (2) is centrifuged and the solid after separation is washed three times with an ethanol-water solution (ethanol to water volume ratio of 1:1), and then placed in a 60℃ oven for 12 h to dry for later use.

[0060] (4) Place the dried material from step (3) in a tube furnace and heat it to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres are obtained.

[0061] Example 4

[0062] A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps:

[0063] (1) Mix 0.15 g NaOH and 100 ml ethylene glycol evenly to obtain solution A, and add 3 g Ce(NO3)3·6H2O to the above solution A and mix evenly to obtain solution B.

[0064] (2) Dissolve 0.2 g of sodium p-aminobenzenesulfonate (SAS) in 5 ml of water to prepare SAS aqueous solution. Add the SAS aqueous solution to the B solution obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, transfer to a high-pressure reactor for reaction. The reaction temperature is 120 ℃ and the reaction time is 18 h.

[0065] (3) The material obtained in step (2) is centrifuged and the solid after separation is washed three times with an ethanol-water solution (ethanol to water volume ratio of 1:1), and then placed in a 60℃ oven for 12 h to dry for later use.

[0066] (4) Place the dried material from step (3) in a tube furnace and heat it to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres are obtained.

[0067] Example 5

[0068] A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps:

[0069] (1) Mix 2 ml of 25wt% ammonia water and 80 ml of glycerol evenly to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to the above solution A and mix evenly to obtain solution B.

[0070] (2) Dissolve 0.2 g of sodium p-aminobenzenesulfonate (SAS) in 5 ml of water to prepare SAS aqueous solution. Add the SAS aqueous solution to the B solution obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, transfer to a high-pressure reactor for reaction. The reaction temperature is 120 ℃ and the reaction time is 18 h.

[0071] (3) The material obtained in step (2) is centrifuged and the solid after separation is washed three times with an ethanol-water solution (ethanol to water volume ratio of 1:1), and then placed in a 60℃ oven for 12 h to dry for later use.

[0072] (4) Place the dried material from step (3) in a tube furnace and heat it to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres are obtained.

[0073] Example 6

[0074] A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps:

[0075] (1) Add 3 g Ce(NO3)3·6H2O to 100 ml ethylene glycol and mix well to obtain solution A.

[0076] (2) Dissolve 0.2 g of sodium p-aminobenzenesulfonate (SAS) in 5 ml of water to prepare SAS aqueous solution. Add the SAS aqueous solution to solution A obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, transfer to a high-pressure reactor for reaction. The reaction temperature is 120 ℃ and the reaction time is 18 h.

[0077] (3) The material obtained in step (2) is centrifuged and the solid after separation is washed three times with an ethanol-water solution (ethanol to water volume ratio of 1:1), and then placed in a 60℃ oven for 12 h to dry for later use.

[0078] (4) Place the dried material from step (3) in a tube furnace and heat it to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres are obtained.

[0079] Example 7

[0080] A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps:

[0081] (1) Mix 2 ml of 25wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to solution A and mix well to obtain solution B.

[0082] (2) 1.35 g of sodium p-aminobenzenesulfonate was added to 5 ml of water to dissolve and prepare SAS aqueous solution. The SAS aqueous solution was added to the B solution obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, the mixture was transferred to a high-pressure reactor for reaction. The reaction temperature was 120 °C and the reaction time was 18 h.

[0083] (3) The material obtained in step (2) is centrifuged and the solid after separation is washed three times with an ethanol-water solution (ethanol to water volume ratio of 1:1), and then placed in a 60℃ oven for 12 h to dry for later use.

[0084] (4) Place the dried material from step (3) in a tube furnace and heat it to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres are obtained.

[0085] Example 8

[0086] A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps:

[0087] (1) Mix 2 ml of 25wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to solution A and mix well to obtain solution B.

[0088] (2) Dissolve 0.07 g of sodium p-aminobenzenesulfonate (SAS) in 5 ml of water to prepare SAS aqueous solution. Add the SAS aqueous solution to solution B obtained in step (1) to obtain dispersion. After stirring and ultrasonic mixing, transfer to high pressure reactor for reaction. The reaction temperature is 120 ℃ and the reaction time is 18 h.

[0089] (3) The material obtained in step (2) is centrifuged and the solid after separation is washed three times with an ethanol-water solution (ethanol to water volume ratio of 1:1), and then placed in a 60℃ oven for 12 h to dry for later use.

[0090] (4) Place the dried material from step (3) in a tube furnace and heat it to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres are obtained.

[0091] Example 9

[0092] A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps:

[0093] (1) Mix 2 ml of 25wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to solution A and mix well to obtain solution B.

[0094] (2) Dissolve 0.2 g of N-acyl taurate sodium in 5 ml of water to prepare an aqueous solution of N-acyl taurate sodium. Add the aqueous solution of N-acyl taurate sodium to the solution B obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, transfer it to a high-pressure reactor for reaction. The reaction temperature is 120 °C and the reaction time is 18 h.

[0095] (3) The material obtained in step (2) is centrifuged and the solid after separation is washed three times with an ethanol-water solution (ethanol to water volume ratio of 1:1), and then placed in a 60 ℃ oven for 12 h to dry for later use.

[0096] (4) Place the dried material from step (3) in a tube furnace and heat it to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres are obtained.

[0097] Example 10

[0098] (1) Mix 2 ml of 25wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to solution A and mix well to obtain solution B.

[0099] (2) Dissolve 0.2 g of polyaniline sulfonic acid in 5 ml of water to prepare a polyaniline sulfonic acid aqueous solution. Add the polyaniline sulfonic acid aqueous solution to the B solution obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, transfer it to a high-pressure reactor for reaction. The reaction temperature is 120 °C and the reaction time is 18 h.

[0100] (3) The material obtained in step (2) is centrifuged and the solid after separation is washed three times with an ethanol-water solution (ethanol to water volume ratio of 1:1), and then placed in a 60 ℃ oven for 12 h to dry for later use.

[0101] (4) Place the dried material from step (3) in a tube furnace and heat it to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres are obtained.

[0102] Example 11

[0103] (1) Mix 2 ml of 25wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to solution A and mix well to obtain solution B.

[0104] (2) Dissolve 0.2 g of sodium o-aminobenzenesulfonate in 5 ml of water to prepare an aqueous solution of sodium o-aminobenzenesulfonate. Add the aqueous solution of sodium o-aminobenzenesulfonate to the solution B obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, transfer it to a high-pressure reactor for reaction. The reaction temperature is 120 °C and the reaction time is 18 h.

[0105] (3) The material obtained in step (2) is centrifuged and the solid after separation is washed three times with an ethanol-water solution (ethanol to water volume ratio of 1:1), and then placed in a 60℃ oven for 12 h to dry for later use.

[0106] (4) Place the dried material from step (3) in a tube furnace and heat it to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres are obtained.

[0107] Comparative Example 1

[0108] This embodiment is the same as Embodiment 3, except that sodium aminobenzenesulfonate was not added in step (2), and ordinary CeO2 nanospheres were finally obtained.

[0109] The microstructure characterization of the hydrophilic CeO2 nanospheres prepared in Example 3 is as follows: Figure 1 As shown. From Figure 1 As can be seen, the prepared CeO2 material consists of uniformly distributed nanospheres with a uniform particle size of approximately 200 nm.

[0110] The XRD pattern of the hydrophilic CeO2 nanospheres prepared in Example 3 is shown below. Figure 2 As shown. Figure 2 This indicates that the hydrophilic CeO2 nanospheres have only CeO2 as their crystal phase, proving that CeO2 has a high crystal phase purity.

[0111] The EDS spectrum of the hydrophilic CeO2 nanospheres prepared in Example 3 is as follows: Figure 3 As shown in A, B, C, and D. Figure 3 This indicates that the hydrophilic CeO2 nanospheres contain not only Ce and O elements, but also S elements, and the contents of each element are shown in Table 1.

[0112] Table 1. Element content of hydrophilic CeO2 nanospheres prepared in Example 3

[0113]

[0114] at the same time, Figure 2 and Figure 3 The results show that the addition of sulfur did not cause the hydrophilic CeO2 nanospheres to develop a new crystal phase, indicating that sulfur is doped into the CeO2 lattice.

[0115] The contact angles of ordinary CeO2 prepared in Comparative Example 1 and hydrophilic CeO2 prepared in Example 3 are as follows: Figure 4 As shown in A and B, the contact angle of ordinary CeO2 is 121°, while that of hydrophilic CeO2 is only 25°. The contact angles of hydrophilic CeO2 prepared in other embodiments were also measured, and the results are shown in Table 2.

[0116] Table 2 Water contact angles of Examples 1-11 and Comparative Example 1

[0117]

[0118] Table 2 shows that the hydrophilic CeO2 prepared in Examples 1-11 all exhibited good hydrophilicity by reducing their water contact angle. The solvothermal reaction temperature significantly affected the hydrophilicity; the hydrophilicity of CeO2 was better at reaction temperatures of 100-200℃, especially 110-130℃. Specifically, the hydrophilic CeO2 prepared with the addition of a precipitant showed higher hydrophilicity compared to the hydrophilic CeO2 prepared without the precipitant (Example 6). Choosing sodium p-aminobenzenesulfonate as the hydrophilic modifier was more beneficial in improving the hydrophilicity of CeO2 compared to adding other hydrophilic modifiers.

[0119] 0.5 g of ordinary CeO2 prepared in Comparative Example 1 and 0.5 g of hydrophilic CeO2 prepared in Example 3 were added to 25 ml of water respectively, and the mixtures were sonicated for 30 min to obtain dispersions. After standing for one day, the dispersions were... Figure 5 As shown in A and B, ordinary CeO2 exhibited significant aggregation, while hydrophilic CeO2 showed good dispersion. The precipitation amounts of both are shown in Table 3.

[0120] Table 3. Precipitation amounts of ordinary and hydrophilic CeO2

[0121]

[0122] Table 3 shows that the precipitation amount of ordinary CeO2 is much higher than that of hydrophilic CeO2, which proves that the hydrophilic CeO2 provided by the present invention has good dispersion stability in water.

[0123] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing hydrophilic cerium oxide nanospheres, characterized in that, Includes the following steps: A cerium salt is mixed with an alcohol compound and a hydrophilic modifier, and then subjected to a solvothermal reaction to obtain a cerium-based precursor; the hydrophilic modifier is one or more of aminobenzenesulfonic acid or its salt, taurine or its salt, N-acyltaurine or its salt, and polyaniline sulfonic acid or its salt. The cerium-based precursor is obtained by calcining and pyrolyzing it at 500-800°C under an oxidizing atmosphere.

2. The preparation method according to claim 1, characterized in that, The alcohol compound is ethylene glycol or glycerol.

3. The preparation method according to claim 1, characterized in that, The molar ratio of cerium salt to hydrophilic modifier is 6.0~7.0:

1.

4. The preparation method according to claim 1, characterized in that, A precipitant is added to the reaction system of a solvothermal reaction.

5. The preparation method according to claim 1, characterized in that, The temperature of the solvothermal reaction is 80~200℃, and the reaction time is 6~20h.

6. The preparation method according to claim 1, characterized in that, After the solvothermal reaction, the mixture is washed and dried, and then subjected to calcination and pyrolysis.

7. A hydrophilic cerium oxide nanosphere, characterized in that, The nanospheres are prepared by the method described in any one of claims 1-6, and have a spherical structure with an average particle size of 50-500 nm. The nanospheres are made of cerium oxide doped with sulfur. The water contact angle of the hydrophilic cerium oxide nanospheres is ≤30°.

8. The hydrophilic cerium oxide nanospheres as described in claim 7, characterized in that, The average particle size of the spherical structure is 150~250nm.

9. The hydrophilic cerium oxide nanospheres as described in claim 7, characterized in that, The water contact angle of the hydrophilic cerium oxide nanospheres is 24~26°.

10. The application of hydrophilic cerium oxide nanospheres obtained by any one of the preparation methods of claims 1-6 or any one of claims 7-9 in catalysis, polishing, luminescence or ultraviolet absorption.

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