Hydrophilic cerium oxide nanosphere as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of cerium oxide nanomaterials, and relates to a hydrophilic cerium oxide nanosphere as well as a preparation method and application thereof. The structure of the hydrophilic cerium oxide nanosphere is a spherical structure with the average particle size of 50-500 nm, and the material of the hydrophilic cerium oxide nanosphere is sulfur-doped cerium oxide; the water contact angle of the hydrophilic cerium oxide nanosphere is less than or equal to 30 degrees. The preparation method comprises the following steps: mixing cerium salt with an alcohol compound and a hydrophilic modifier, and then carrying out solvothermal reaction to obtain a cerium-based precursor; and heating the cerium-based precursor to 500-800 DEG C under an oxidizing atmosphere condition, and carrying out calcination pyrolysis. Elements such as S are doped into the hydrophilic cerium oxide nanosphere provided by the invention, and the inert surface of cerium oxide is changed into a hydrophilic surface, so that the hydrophilic performance of cerium oxide is essentially changed, the dispersion stability of cerium oxide in water or alcohol is favorably improved, and the hydrophilic cerium oxide nanosphere shows a wide application prospect in the fields of catalysis, polishing, luminescence, ultraviolet absorption and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of cerium oxide nanomaterials and relates to hydrophilic cerium oxide nanospheres and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Cerium oxide (CeO2) is a rare earth oxide material with excellent oxygen storage and release capacity, high catalytic activity, good UV shielding properties, and chemical stability. It is primarily used in automotive exhaust purification catalysts, polishing powders for precision glass / optical components, glass decolorizers and clarifiers, electrolytes for solid oxide fuel cells, and UV-absorbing materials. Cerium oxide is typically synthesized using high-temperature hydrothermal or calcination steps. However, the resulting cerium oxide nanoparticles are prone to aggregation and exhibit poor dispersion stability in water or alcohol, limiting their application.

[0004] In order to improve the dispersion stability of cerium oxide in water or alcohol, hydrophilic polymers or surfactants can be used to treat cerium oxide for hydrophilicity. 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 is the operation step cumbersome, but it also cannot fundamentally solve the intrinsic properties of cerium oxide and has strong limitations. Summary of the Invention

[0005] In order to address the deficiencies of the prior art, the present invention aims to provide a hydrophilic cerium oxide nanosphere, a preparation method and application thereof. The hydrophilic cerium oxide nanosphere provided by the present invention is doped with elements such as N and S, which changes the inert surface of cerium oxide into a hydrophilic surface, essentially changing the hydrophilic properties of cerium oxide, which is beneficial to improving its dispersion stability in water or alcohol, and shows broad application prospects in the fields of catalysis, polishing, luminescence, ultraviolet absorption, etc.

[0006] In order to achieve the above object, the technical solution of the present invention is: In a first aspect, a hydrophilic cerium oxide nanosphere is a spherical structure with an average particle size of 50 to 500 nm, and is made of cerium oxide doped with sulfur; the water contact angle of the hydrophilic cerium oxide nanosphere is ≤30°.

[0007] The hydrophilic cerium oxide nanospheres provided by the present invention are made of sulfur-doped cerium oxide. S has a strong electronegativity and easily forms hydrogen bonds with water or alcohol. In addition, after doping, the cerium oxide nanospheres produce defective structures, which makes the doped cerium oxide have a certain charge. Through the synergistic effects of the above, the hydrophilic properties of cerium oxide are increased, while its dispersion stability in water or alcohol is also improved.

[0008] On the other hand, a method for preparing hydrophilic cerium oxide nanospheres comprises 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 polyanilinesulfonic acid or its salt; The cerium-based precursor is heated to 500-800° C. in an oxidizing atmosphere, and calcined and pyrolyzed to obtain the product.

[0009] In the solvent-thermal reaction process of the present invention, an alcohol compound is added, which not only serves as a reducing agent to adjust the oxidation state of cerium, but also serves as a structure-directing agent to control particle size and morphology, and also serves as a complexing agent to stabilize metal ions and control the crystallization rate. Simultaneously, the present invention introduces amino and sulfonic acid groups into a cerium-based precursor by adding sodium aminobenzenesulfonate. Then, sulfur is doped into the cerium oxide through oxidative calcination and thermal decomposition, and hydrophilic elements (such as sulfur) are doped into the cerium oxide without changing the crystal structure of the cerium oxide. The morphology is controlled to be a spherical structure with an average particle size of 50 to 500 nm, so that hydrophilic cerium oxide nanospheres having the characteristics described in the first aspect of the present invention are formed, thereby increasing the hydrophilicity of the cerium oxide and simultaneously increasing its dispersion stability in water or alcohol.

[0010] In a third aspect, a use of the hydrophilic cerium oxide nanospheres or the hydrophilic cerium oxide nanospheres obtained by the above preparation method in catalysis, polishing, luminescence or ultraviolet absorption.

[0011] The beneficial effects of the present invention are: The hydrophilic cerium oxide nanospheres provided by the present invention are prepared by doping cerium oxide with sulfur. Due to the strong electronegativity of sulfur, hydrogen bonds are easily formed with water or alcohol. In addition, the defective structure generated by the incorporation of sulfur can make the cerium oxide have a certain charge, which not only increases the hydrophilicity of the cerium oxide nanospheres, but also increases the electrostatic repulsion between the cerium oxide particles, thereby increasing their dispersibility in water or alcohol.

[0012] In the process of preparing hydrophilic cerium oxide nanospheres, sodium aminobenzenesulfonate is added in a solvothermal reaction to introduce hydrophilic groups such as amino and sulfonic acid groups into the cerium-based precursor. The precursor is then subjected to oxidative calcination and thermal decomposition, thereby doping sulfur into the cerium oxide. This increases the hydrophilicity of the cerium oxide and, consequently, its dispersibility in water or alcohol. The preparation method of the present invention is simple to operate, fundamentally improves the hydrophilicity and dispersibility of cerium oxide, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0014] Figure 1 This is a SEM image of the hydrophilic CeO2 prepared in Example 3 of the present invention; Figure 2 This is the XRD pattern of the hydrophilic CeO2 prepared in Example 3 of the present invention; Figure 3 This is the EDS spectrum of the hydrophilic CeO2 prepared in Example 3 of the present invention, A is the electron micrograph, B is Ce Lα1, C is O Kα1, and D is S Kα1; Figure 4 The contact angle results of ordinary CeO2 (A) prepared in Comparative Example 1 of the present invention and hydrophilic CeO2 (B) prepared in Example 3 are shown; Figure 5 These are pictures of ordinary CeO2 (A) prepared in Comparative Example 1 of the present invention and hydrophilic CeO2 (B) prepared in Example 3 after standing in water for one day. DETAILED DESCRIPTION

[0015] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0016] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0017] Since cerium oxide prepared by existing methods is easy to aggregate and has poor dispersion stability in water or alcohol, and its modification method is difficult to fundamentally change the hydrophilicity of cerium oxide, the present invention proposes a hydrophilic cerium oxide nanosphere and its preparation method and application.

[0018] A typical embodiment of the present invention provides 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°.

[0019] In some embodiments, the average particle size of the spherical structures is 100-300 nm, preferably 150-250 nm.

[0020] In some embodiments, the water contact angle of the hydrophilic cerium oxide nanospheres is 20-30°, preferably 24-26°.

[0021] Another embodiment of the present invention provides a method for preparing hydrophilic cerium oxide nanospheres, comprising 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 (which may be p-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, or o-aminobenzenesulfonic acid) or a salt thereof, taurine or a salt thereof, N-acyltaurine or a salt thereof, and polyanilinesulfonic acid or a salt thereof; The cerium-based precursor is heated to 500-800° C. in an oxidizing atmosphere, and calcined and pyrolyzed to obtain the product.

[0022] The cerium salt described in the present invention refers to a compound whose cation is a cerium ion, such as cerium nitrate, cerium sulfate, cerium chloride, cerium acetate, etc.

[0023] The alcohol compounds described in the present invention refer to compounds containing alcoholic hydroxyl groups, such as methanol, ethanol, ethylene glycol, glycerol, etc., among which alcohol compounds containing at least two hydroxyl groups such as ethylene glycol and glycerol have better effects on morphology regulation and crystallization rate regulation.

[0024] In some embodiments, the molar ratio of the cerium salt to the hydrophilic modifier is 1.0 to 20.0:1, preferably 1.0 to 10.0:1, more preferably 4.0 to 9.0:1, and even more preferably 6.0 to 7.0:1. Studies have shown that a molar ratio of cerium salt to hydrophilic modifier of 6.0 to 7.0:1 achieves a better hydrophilic effect.

[0025] In some embodiments, a precipitant is added to the solvothermal reaction system. By adding the precipitant, the pH of the solution is adjusted to promote precipitation and aging of the cerium salt, further facilitating the adjustment of the precursor morphology. The precipitant described herein is a compound that precipitates the cerium salt by adjusting the pH. It can include ammonia, alkali metal hydroxides (Group I metals such as Li, Na, and K), and the like.

[0026] The solvothermal reaction described herein is a reaction conducted under closed conditions using a non-aqueous solvent and heating the reaction system to a pressure above atmospheric pressure. In some embodiments, the solvothermal reaction temperature is 80-200°C. Specifically, the solvothermal reaction time is 6-20 hours. Solvothermal reactions are more effective under these conditions, particularly when the solvothermal reaction temperature is 115-125°C.

[0027] In some embodiments, the solvent thermal reaction is followed by washing and drying, and then calcination and pyrolysis are performed to remove unreacted raw materials and completely remove the solvent attached to the precursor, thereby preventing the temperature from rising too quickly during the calcination and pyrolysis process, which would cause the solvent to evaporate too quickly and affect the structure of the cerium oxide nanospheres.

[0028] Specifically, an ethanol-water solution is used for washing. The washing effect of the ethanol-water solution is better. More specifically, the volume ratio of ethanol to water in the ethanol-water solution is 1:0.9-1.1.

[0029] Specifically, the drying temperature is 55-65°C and the drying time is 10-14 hours, which is conducive to completely removing the solvent.

[0030] In some embodiments, the calcination and pyrolysis time is 5 to 10 hours.

[0031] A third embodiment of the present invention provides a use of the hydrophilic cerium oxide nanospheres or the hydrophilic cerium oxide nanospheres obtained by the above preparation method in catalysis, polishing, luminescence or ultraviolet absorption.

[0032] In order to enable those skilled in the art to more clearly 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.

[0033] Example 1 A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps: (1) Mix 2 ml of 25 wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to the above solution A and mix well to obtain solution B.

[0034] (2) 0.2 g of sodium p-aminobenzenesulfonate (SAS) was added to 5 ml of water to dissolve it to prepare a SAS aqueous solution. The SAS aqueous solution was added to the solution B obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, the dispersion was transferred to a high-pressure reactor for reaction at a temperature of 80 °C and a reaction time of 18 h.

[0035] (3) The material obtained in step (2) was centrifuged and the separated solid was washed three times with an ethanol-water solution (the volume ratio of ethanol to water was 1:1), and then placed in a 60 ° C oven for 12 h for drying.

[0036] (4) The material dried in step (3) was placed in a tube furnace and heated to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres were obtained.

[0037] Example 2 A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps: (1) Mix 2 ml of 25 wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to the above solution A and mix well to obtain solution B.

[0038] (2) 0.2 g of sodium p-aminobenzenesulfonate (SAS) was added to 5 ml of water to dissolve it to prepare a SAS aqueous solution. The SAS aqueous solution was added to the solution B obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, the dispersion was transferred to a high-pressure reactor for reaction at a temperature of 200 °C and a reaction time of 18 h.

[0039] (3) The material obtained in step (2) was centrifuged and the separated solid was washed three times with an ethanol-water solution (the volume ratio of ethanol to water was 1:1), and then placed in a 60°C oven for 12 h for drying.

[0040] (4) The material dried in step (3) was placed in a tube furnace and heated to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres were obtained.

[0041] Example 3 A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps: (1) Mix 2 ml of 25 wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to the above solution A and mix well to obtain solution B.

[0042] (2) 0.2 g of sodium p-aminobenzenesulfonate (SAS) was added to 5 ml of water to dissolve it to prepare a SAS aqueous solution. The SAS aqueous solution was added to the solution B obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, the dispersion was transferred to a high-pressure reactor for reaction at a temperature of 120 °C and a reaction time of 18 h.

[0043] (3) The material obtained in step (2) was centrifuged and the separated solid was washed three times with an ethanol-water solution (the volume ratio of ethanol to water was 1:1), and then placed in a 60°C oven for 12 h for drying.

[0044] (4) The material dried in step (3) was placed in a tube furnace and heated to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres were obtained.

[0045] Example 4 A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps: (1) Mix 0.15 g of NaOH and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to the above solution A and mix well to obtain solution B.

[0046] (2) 0.2 g of sodium p-aminobenzenesulfonate (SAS) was added to 5 ml of water to dissolve it to prepare a SAS aqueous solution. The SAS aqueous solution was added to the solution B obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, the dispersion was transferred to a high-pressure reactor for reaction at a temperature of 120 °C and a reaction time of 18 h.

[0047] (3) The material obtained in step (2) was centrifuged and the separated solid was washed three times with an ethanol-water solution (the volume ratio of ethanol to water was 1:1), and then placed in a 60°C oven for 12 h for drying.

[0048] (4) The material dried in step (3) was placed in a tube furnace and heated to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres were obtained.

[0049] Example 5 A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps: (1) Mix 2 ml of 25 wt% ammonia water and 80 ml of propylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to the above solution A and mix well to obtain solution B.

[0050] (2) 0.2 g of sodium p-aminobenzenesulfonate (SAS) was added to 5 ml of water to dissolve it to prepare a SAS aqueous solution. The SAS aqueous solution was added to the solution B obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, the dispersion was transferred to a high-pressure reactor for reaction at a temperature of 120 °C and a reaction time of 18 h.

[0051] (3) The material obtained in step (2) was centrifuged and the separated solid was washed three times with an ethanol-water solution (the volume ratio of ethanol to water was 1:1), and then placed in a 60°C oven for 12 h for drying.

[0052] (4) The material dried in step (3) was placed in a tube furnace and heated to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres were obtained.

[0053] Example 6 A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps: (1) Add 3 g of Ce(NO3)3·6H2O to 100 ml of ethylene glycol and mix well to obtain solution A.

[0054] (2) 0.2 g of sodium p-aminobenzenesulfonate (SAS) was added to 5 ml of water to dissolve it to prepare a SAS aqueous solution. The SAS aqueous solution was added to the solution A obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, the dispersion was transferred to a high-pressure reactor for reaction at a temperature of 120 °C and a reaction time of 18 h.

[0055] (3) The material obtained in step (2) was centrifuged and the separated solid was washed three times with an ethanol-water solution (the volume ratio of ethanol to water was 1:1), and then placed in a 60°C oven for 12 h for drying.

[0056] (4) The material dried in step (3) was placed in a tube furnace and heated to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres were obtained.

[0057] Example 7 A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps: (1) Mix 2 ml of 25 wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to the above solution A and mix well to obtain solution B.

[0058] (2) 1.35 g of sodium p-aminobenzenesulfonate was added to 5 ml of water to dissolve it to prepare a SAS aqueous solution. The SAS aqueous solution was added to the solution B obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, the dispersion was transferred to a high-pressure reactor for reaction at a temperature of 120 °C and a reaction time of 18 h.

[0059] (3) The material obtained in step (2) was centrifuged and the separated solid was washed three times with an ethanol-water solution (the volume ratio of ethanol to water was 1:1), and then placed in a 60°C oven for 12 h for drying.

[0060] (4) The material dried in step (3) was placed in a tube furnace and heated to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres were obtained.

[0061] Example 8 A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps: (1) Mix 2 ml of 25 wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to the above solution A and mix well to obtain solution B.

[0062] (2) 0.07 g of sodium p-aminobenzenesulfonate (SAS) was added to 5 ml of water to dissolve it to prepare a SAS aqueous solution. The SAS aqueous solution was added to the solution B obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, the dispersion was transferred to a high-pressure reactor for reaction at a temperature of 120 °C and a reaction time of 18 h.

[0063] (3) The material obtained in step (2) was centrifuged and the separated solid was washed three times with an ethanol-water solution (the volume ratio of ethanol to water was 1:1), and then placed in a 60°C oven for 12 h for drying.

[0064] (4) The material dried in step (3) was placed in a tube furnace and heated to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres were obtained.

[0065] Example 9 A method for preparing hydrophilic CeO2 nanospheres, comprising the following steps: (1) Mix 2 ml of 25 wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to the above solution A and mix well to obtain solution B.

[0066] (2) 0.2 g of sodium N-acyl taurate was added to 5 ml of water to dissolve it to prepare an aqueous solution of sodium N-acyl taurate. The aqueous solution of sodium N-acyl taurate was added to solution B obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, the dispersion was transferred to a high-pressure reactor for reaction at a temperature of 120 °C and a reaction time of 18 h.

[0067] (3) The material obtained in step (2) was centrifuged and the separated solid was washed three times with an ethanol-water solution (the volume ratio of ethanol to water was 1:1), and then placed in a 60 ° C oven for 12 h for drying.

[0068] (4) The material dried in step (3) was placed in a tube furnace and heated to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres were obtained.

[0069] Example 10 (1) Mix 2 ml of 25 wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to the above solution A and mix well to obtain solution B.

[0070] (2) 0.2 g of polyaniline sulfonic acid was added to 5 ml of water to dissolve it to prepare a polyaniline sulfonic acid aqueous solution. The polyaniline sulfonic acid aqueous solution was added to the solution B obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, the dispersion was transferred to a high-pressure reactor for reaction at a reaction temperature of 120 °C and a reaction time of 18 h.

[0071] (3) The material obtained in step (2) was centrifuged and the separated solid was washed three times with an ethanol-water solution (the volume ratio of ethanol to water was 1:1), and then placed in a 60 ° C oven for 12 h for drying.

[0072] (4) The material dried in step (3) was placed in a tube furnace and heated to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres were obtained.

[0073] Example 11 (1) Mix 2 ml of 25 wt% ammonia water and 100 ml of ethylene glycol to obtain solution A. Add 3 g of Ce(NO3)3·6H2O to the above solution A and mix well to obtain solution B.

[0074] (2) 0.2 g of sodium o-aminobenzenesulfonate was added to 5 ml of water to dissolve it to prepare an aqueous sodium o-aminobenzenesulfonate solution. The aqueous sodium o-aminobenzenesulfonate solution was added to solution B obtained in step (1) to obtain a dispersion. After stirring and ultrasonic mixing, the dispersion was transferred to a high-pressure reactor for reaction at a reaction temperature of 120 °C and a reaction time of 18 h.

[0075] (3) The material obtained in step (2) was centrifuged and the separated solid was washed three times with an ethanol-water solution (the volume ratio of ethanol to water was 1:1), and then placed in a 60°C oven for 12 h for drying.

[0076] (4) The material dried in step (3) was placed in a tube furnace and heated to 600 °C in an air atmosphere for pyrolysis for 5 h. After pyrolysis, hydrophilic CeO2 nanospheres were obtained.

[0077] Comparative Example 1 This embodiment is the same as embodiment 3, except that sodium aminobenzenesulfonate is not added in step (2), and ordinary CeO2 nanospheres are finally obtained.

[0078] The microstructure of the hydrophilic CeO2 nanospheres prepared in Example 3 is characterized as follows: Figure 1 As shown. Figure 1 It can be seen that the prepared CeO2 material is uniformly distributed nanospheres with a uniform particle size of about 200 nm.

[0079] The XRD spectrum of the hydrophilic CeO2 nanospheres prepared in Example 3 is as follows: Figure 2 shown. Figure 2 It shows that the crystal phase of the hydrophilic CeO2 nanospheres is only CeO2, proving that the crystal phase purity of CeO2 is high.

[0080] 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 It shows that the hydrophilic CeO2 nanospheres contain not only Ce and O elements, but also S elements. The contents of each element are shown in Table 1.

[0081] Table 1 Content of various elements in the hydrophilic CeO2 nanospheres prepared in Example 3

[0082] at the same time, Figure 2 and Figure 3 The results show that the addition of S element does not produce a new crystal phase of hydrophilic CeO2 nanospheres, which indicates that the S element is doped into the CeO2 lattice.

[0083] The contact angles of the ordinary CeO2 prepared in Comparative Example 1 and the hydrophilic CeO2 prepared in Example 3 are as follows: Figure 4 As shown in Figures A and B, the contact angle of ordinary CeO2 is 121°, while the contact angle of hydrophilic CeO2 is only 25°. The contact angles of hydrophilic CeO2 prepared in other examples were also tested, and the results are shown in Table 2.

[0084] Table 2 Water contact angles of Examples 1-11 and Comparative Example 1

[0085] Table 2 shows that the hydrophilic CeO2 prepared in Examples 1-11 all exhibited low water contact angles, indicating excellent hydrophilic properties. The solvothermal reaction temperature significantly impacted the hydrophilic properties, with the hydrophilic CeO2 exhibiting enhanced hydrophilicity when the reaction temperature ranged from 100°C to 200°C, particularly from 110°C to 130°C. Compared to the hydrophilic CeO2 prepared without the addition of a precipitant (Example 6), the hydrophilic CeO2 prepared with the addition of a precipitant exhibited even higher hydrophilicity. Compared to other hydrophilic modifiers, the use of sodium p-aminobenzenesulfonate as a hydrophilic modifier was more beneficial in improving the hydrophilicity of the hydrophilic CeO2.

[0086] 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, and ultrasonicated for 30 min to obtain a dispersion. After standing for one day, the dispersion was Figure 5 As shown in Figures A and B, the ordinary CeO2 exhibits obvious coagulation, while the hydrophilic CeO2 is well dispersed. The precipitation amounts of the two are shown in Table 3.

[0087] Table 3 Precipitation amount of ordinary and hydrophilic CeO2

[0088] 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.

[0089] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A hydrophilic cerium oxide nanosphere, characterized in that The structure is a spherical structure with an average particle size of 50-500 nm, and its material is cerium oxide doped with sulfur; the water contact angle of the hydrophilic cerium oxide nanospheres is ≤30°.

2. The hydrophilic cerium oxide nanospheres according to claim 1, wherein: The average particle size of the spherical structure is 150~250nm.

3. The hydrophilic cerium oxide nanospheres according to claim 1, wherein: The water contact angle of the hydrophilic cerium oxide nanospheres is 24-26°.

4. A method for preparing hydrophilic cerium oxide nanospheres, characterized in that: The steps include: 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 polyanilinesulfonic acid or its salt; The cerium-based precursor is heated to 500-800° C. in an oxidizing atmosphere, and calcined and pyrolyzed to obtain the product.

5. The preparation method according to claim 4, characterized in that: The alcohol compound is ethylene glycol or glycerol.

6. The preparation method according to claim 4, wherein: The molar ratio of the cerium salt to the hydrophilic modifier is 6.0-7.0:

1.

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

8. The preparation method according to claim 4, wherein: The temperature of the solvothermal reaction is 80~200℃, and the time of the solvothermal reaction is 6~20h.

9. The preparation method according to claim 4, wherein: The solvent thermal reaction is followed by washing and drying, and then calcination and pyrolysis.

10. Use of the hydrophilic cerium oxide nanospheres according to any one of claims 1 to 3 or the hydrophilic cerium oxide nanospheres obtained by the preparation method according to any one of claims 4 to 9 in catalysis, polishing, luminescence or ultraviolet absorption.

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