A method for preparing high-entropy oxide nanoparticles

Abstract

This invention provides a method for preparing high-entropy oxide nanoparticles, comprising: S1, dissolving at least five metal salts in water at an equimolar or near-equimolar ratio to obtain a mixed metal salt solution; S2, preparing a precipitant solution, adding a polymeric dispersant with carboxyl or anhydride-rich side chains and an ionic surfactant to the precipitant solution to obtain a precipitant solution containing a composite dispersant; S3, under stirring conditions, slowly adding the mixed metal salt solution dropwise to the precipitant solution containing the composite dispersant to carry out a co-precipitation reaction to obtain a high-entropy hydroxide precursor; S4, calcining the high-entropy hydroxide precursor to obtain high-entropy oxide nanoparticles. This invention, by introducing a composite dispersant system and combining it with a reverse co-precipitation process, effectively solves the problems of heterogeneous agglomeration and component segregation in the co-precipitation process of multi-metal ions, and prepares high-entropy oxide nanoparticles with highly uniform elemental distribution and high dispersion.

Description

Technical Field

[0001] This invention relates to the field of high-entropy oxide nanomaterials technology, and specifically to a method for preparing high-entropy oxide nanoparticles. Background Technology

[0002] High-entropy oxides (HEOs) exhibit great potential in catalysis and energy storage due to their high-entropy effect and lattice distortion effect. Coprecipitation is one of the mainstream methods for preparing HEOs, but it faces a key common technical challenge: because the precipitation pH and kinetic rates of at least five metal ions in the system vary significantly, component segregation and stepwise precipitation easily occur during coprecipitation, resulting in uneven composition and severe hard agglomeration of the generated precursor particles. The oxide particles obtained after calcination have large particle size, low specific surface area, and uneven elemental distribution, which severely restricts their performance.

[0003] Existing technologies attempt to improve agglomeration using dispersants, but these are mostly general solutions that fail to address the unique complexity of co-precipitation in high-entropy systems. For example, patent CN118594558A discloses the use of polyethylene glycol or ethylene glycol as a dispersant in the preparation of perovskite-type high-entropy catalysts with specific ratios. These single, nonionic dispersants rely primarily on steric hindrance, and in the dynamic precipitation environment of complex ion coexistence, their effectiveness in regulating the precipitation sequence of different metal ions and suppressing initial agglomeration caused by different precipitation rates is limited. Patent CN118930227A discloses the use of a combination of multiple dispersants (such as polyvinylpyrrolidone and sodium dodecylbenzenesulfonate) in the preparation of target slurry through sand milling. However, this technology addresses the physical agglomeration problem during the post-processing grinding of synthesized solid oxide powders and does not involve in-situ controlled nucleation and growth from the ionic state in the liquid phase.

[0004] Therefore, there is an urgent need for a method that can actively regulate the co-precipitation behavior of multiple metal ions during the co-precipitation synthesis stage, so as to achieve uniform nucleation and stable growth of nanoparticles from the source. Summary of the Invention

[0005] In view of the technical problems existing in the background art, the present invention provides a method for preparing high-entropy oxide nanoparticles, aiming to solve the technical problems of heterogeneous agglomeration and component segregation in the process of multi-metal ion co-precipitation.

[0006] In a first aspect, the present invention provides a method for preparing high-entropy oxide nanoparticles, comprising the following steps: S1. Dissolve at least five metal salts in water in an equimolar or near-equimolar ratio to obtain a mixed metal salt solution; S2. Prepare a precipitant solution by adding a high molecular weight polymer dispersant and anionic surfactant with side chains rich in carboxyl or anhydride groups to the precipitant solution to obtain a precipitant solution containing a composite dispersant. S3. Under stirring conditions, the metal salt mixed solution is slowly added dropwise to the precipitant solution containing the composite dispersant to carry out a co-precipitation reaction. After solid-liquid separation, washing, and drying, a high-entropy hydroxide precursor is obtained. S4. High-entropy oxide nanoparticles are obtained by calcining the high-entropy hydroxide precursor.

[0007] Preferably, in step S1, the metal salt is selected from nitrates, sulfates and / or chlorides of transition metals; the transition metals include Fe, Co, Ni, Cr, Mn, Cu, Zn, Mg and Al; the concentration of the metal salt mixed solution is 0.01~1 mol / L.

[0008] Preferably, in step S2, the concentration of the precipitant solution is 0.1~5 mol / L; the precipitant in the precipitant solution includes at least one of sodium hydroxide, ammonia, sodium carbonate, ammonium bicarbonate, and sodium bicarbonate.

[0009] Preferably, in step S2, the amount of polymeric dispersant added is 0.5% to 5% of the total mass of the target metal oxide; the amount of ionic surfactant added is 0.1% to 2% of the total mass of the target metal oxide.

[0010] Preferably, in step S2, the ionic surfactant includes at least one of sodium dodecylbenzenesulfonate and hexadecyltrimethylammonium bromide.

[0011] Preferably, in step S2, the polymer dispersant includes at least one of polyacrylic acid, polymethacrylic acid, and styrene-maleic anhydride copolymer.

[0012] Preferably, in step S3, the conditions for the coprecipitation reaction are as follows: the reaction temperature is 60~80℃, the reaction time is 2~4 hours, and the pH value of the reaction system is 9~11.

[0013] Preferably, in step S3, the drying temperature is 80~100℃ and the drying time is 12~24h.

[0014] Preferably, in step S4, the calcination temperature is 400~600℃, the calcination time is 2~4 hours, and the calcination atmosphere is air.

[0015] In a second aspect, the present invention provides high-entropy oxide nanoparticles prepared by the preparation method described in the first aspect.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention adopts a composite dispersion system of a high molecular weight polymer dispersant with carboxyl-rich side chain and an ionic surfactant. Through the selective coordination ability of metal ions, the precipitation kinetics of various metal ions are effectively controlled, so that metal ions can nucleate synchronously under similar conditions, thereby fundamentally inhibiting the occurrence of component segregation. (2) The present invention significantly inhibits agglomeration during the coprecipitation process by constructing a synergistic stabilization mechanism with polymer dispersants and ionic surfactants, so that the precursor particles are kept in a nanoscale dispersed state; the composite dispersant can be completely decomposed and removed during calcination, without introducing impurity elements; (3) The high-entropy oxide nanoparticles obtained by this invention have the characteristics of high dispersibility, large specific surface area and uniform element distribution; (4) The method of the present invention is simple, low-cost, easy to scale up, and applicable to the preparation of a variety of high-entropy oxide systems, and has broad prospects for industrial application. Attached Figure Description

[0017] Figure 1 EDS image of the high-entropy oxide nanoparticles obtained in Example 1 of this invention; Figure 2 This is an EDS image of the high-entropy oxide nanoparticles prepared in Comparative Example 1 of this invention. Detailed Implementation

[0018] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0019] To address the technical problems of heterogeneous agglomeration and component segregation of ions during the co-precipitation process of high-entropy oxide nanoparticles prepared by existing multi-metal co-precipitation methods, this invention provides a method for preparing high-entropy oxide nanoparticles. By introducing a composite dispersant system with "kinetic regulation" and "dual stabilization of steric hindrance and electrostatic repulsion" functions, combined with an optimized precipitation process, the heterogeneous agglomeration and component segregation problems during multi-metal ion co-precipitation are effectively solved, resulting in high-entropy oxide nanoparticles with highly uniform elemental distribution and high dispersion.

[0020] In a first aspect, embodiments of the present invention provide a method for preparing high-entropy oxide nanoparticles, comprising the following steps: S1. Dissolve at least five metal salts in water in an equimolar or near-equimolar ratio to obtain a mixed metal salt solution; S2. Prepare a precipitant solution by adding a high molecular weight polymer dispersant and anionic surfactant with side chains rich in carboxyl or anhydride groups to the precipitant solution to obtain a precipitant solution containing a composite dispersant. S3. Under stirring conditions, the metal salt mixed solution is slowly added dropwise to the precipitant solution containing the composite dispersant to carry out a co-precipitation reaction. After solid-liquid separation, washing, and drying, a high-entropy hydroxide precursor is obtained. S4. High-entropy oxide nanoparticles are obtained by calcining the high-entropy hydroxide precursor.

[0021] In the technical solution of this invention embodiment, the invention employs a functionalized compounding of a polymer dispersant with specific functional groups and an ionic surfactant. Specifically, the carboxyl or anhydride groups of the polymer (such as polyacrylic acid, styrene-maleic anhydride copolymer) react with different metal ions (such as Fe...). 3+ Co 2+ Ni 2+ Cr 3+ The differential complexation constants of these dispersants allow them to selectively complex rapidly precipitating ions in the early stages of precipitation, thus "buffering" the precipitation rate and promoting the synchronous co-precipitation of all metal ions, ensuring component homogeneity from the kinetic source. Ionic surfactants (such as sodium dodecylbenzenesulfonate and hexadecyltrimethylammonium bromide) provide strong electrostatic repulsion. These two dispersants construct a synergistic stabilization mechanism: the hydrophobic segments of the polymer and the long alkyl chains of the ionic surfactant interact hydrophobically to form a denser and more robust "composite micelle" adsorption layer on the particle surface. This composite layer simultaneously exerts a triple effect of "kinetic buffering" (through functional group complexation), "steric hindrance" (through polymer chains and composite micelles), and "electrostatic repulsion" (through ionic end groups), resulting in a stabilizing effect far superior to a single mechanism. In addition, in the coprecipitation reaction, the present invention adopts a reverse coprecipitation process, in which a solution containing multiple metal ions is added dropwise to a precipitant containing a composite dispersant, so that the particles nucleate and grow in an alkaline environment most conducive to dispersion, which further enhances the effect of the dispersant and avoids rapid agglomeration caused by local overconcentration during forward addition.

[0022] Furthermore, in some embodiments, in step S1, the metal salt is selected from nitrates, sulfates and / or chlorides of transition metals; the transition metals include Fe, Co, Ni, Cr, Mn, Cu, Zn, Mg and Al.

[0023] Furthermore, in some embodiments, in step S1, the concentration of the metal salt mixed solution is 0.01~1 mol / L.

[0024] Furthermore, in some embodiments, in step S2, the concentration of the precipitant solution is 0.1~5 mol / L; the precipitant in the precipitant solution includes at least one of sodium hydroxide, ammonia, sodium carbonate, ammonium bicarbonate, and sodium bicarbonate.

[0025] Furthermore, in some embodiments, in step S2, the amount of polymeric dispersant added is 0.5% to 5% of the total mass of the target metal oxide, and the amount of ionic surfactant added is 0.1% to 2% of the total mass of the target metal oxide.

[0026] In the technical solution of this invention, the ratio of polymeric dispersant to ionic surfactant is obtained through extensive experimental optimization. If the amount of polymeric dispersant is too low, the steric hindrance effect is insufficient, making it difficult to effectively inhibit particle aggregation; if the amount is too high, it will hinder the mass transfer process and may lead to over-coating. If the amount of ionic surfactant is too low, the electrostatic repulsion effect is weak; if the amount is too high, it may interfere with the normal progress of the precipitation reaction.

[0027] Furthermore, in some embodiments, in step S2, the polymeric dispersant includes at least one of polyacrylic acid, polymethacrylic acid, and styrene-maleic anhydride copolymer.

[0028] In the technical solution of this invention embodiment, polyacrylic acid and polymethacrylic acid have a straight-chain structure, high carboxyl group density, and strong complexing ability for metal ions; the styrene-maleic anhydride copolymer has a rigid benzene ring skeleton and reactive anhydride groups, and the anhydride hydrolyzes into carboxylate under alkaline conditions, while the benzene ring structure gives it a stronger steric hindrance effect.

[0029] Furthermore, in some embodiments, in step S2, the ionic surfactant includes at least one of sodium dodecylbenzenesulfonate and hexadecyltrimethylammonium bromide.

[0030] In the technical solution of this invention embodiment, the selection of ionic surfactant is related to the average isoelectric point of the target metal ion. When precipitation is performed under alkaline conditions, anionic surfactants such as sodium dodecylbenzenesulfonate (SDBS) are preferred to enhance the negative charge on the particle surface and strengthen electrostatic repulsion.

[0031] Furthermore, in some embodiments, in step S3, the rate of slow addition is 0.5~5 mL / min.

[0032] Furthermore, in some embodiments, the conditions for the coprecipitation reaction in step S3 are as follows: the reaction temperature is 60~80℃, the reaction time is 2~4 hours, and the pH value of the reaction system is 9~11.

[0033] Furthermore, in some embodiments, in step S3, the drying temperature is 80~100℃ and the drying time is 12~24h.

[0034] Furthermore, in some embodiments, in step S4, the calcination temperature is 400~600℃, the calcination time is 2~4 hours, and the calcination atmosphere is air.

[0035] In the technical solution of this invention embodiment, the calcination temperature range allows the hydroxide precursor to be completely converted into the oxide crystalline phase, while simultaneously inhibiting abnormal grain growth caused by high temperature. During the calcination process, the composite dispersant undergoes thermal decomposition, escaping in the form of gaseous products such as CO2, H2O, and NH3, leaving no impurities and ensuring the high purity of the final product.

[0036] Secondly, embodiments of the present invention provide high-entropy oxide nanoparticles, which are prepared by the preparation method described in the first aspect.

[0037] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0038] Example 1 A method for preparing high-entropy oxide nanoparticles, the specific steps of which are as follows: (1) Preparation of metal salt solution: Take 0.01 mol each of magnesium nitrate, cobalt nitrate, nickel nitrate, copper nitrate and zinc nitrate in equal molar ratio, dissolve them in 500 mL of deionized water to obtain a mixed metal salt solution; (2) Preparation of precipitant: Prepare a 2 mol / L sodium hydroxide / sodium carbonate (molar ratio 1:2) mixed solution as precipitant; (3) Construction of synergistic dispersion system: Add polymeric dispersant PAA (polyacrylic acid, 1.5 wt% of the total mass of the target metal oxide) and ionic surfactant SDBS (sodium dodecylbenzene sulfonate, 0.8 wt% of the total mass of the target metal oxide) to the precipitant solution and stir until completely dissolved to form a precipitant solution containing composite dispersant; (4) Reverse coprecipitation reaction: Under stirring conditions, the metal salt mixed solution prepared in step (1) is slowly added dropwise (dropping rate 1 mL / min) to the precipitant solution containing composite dispersant prepared in step (3) by a constant flow pump. The pH value of the entire reaction system is controlled to be 10, the reaction temperature is 60℃, and the reaction time is 2 hours to obtain a high entropy hydroxide coprecipitation suspension. (5) Washing and drying: After filtering the high-entropy hydroxide coprecipitate suspension, the precipitate was washed with deionized water and ethanol until neutral, and then vacuum dried at 80 °C for 12 hours to obtain a loose high-entropy hydroxide precursor powder. (6) Calcination treatment: The dried precursor was calcined in air at a heating rate of 2 °C / min to 500 °C for 3 hours, and then naturally cooled to obtain MgCoNiCuZnO high-entropy oxide nanoparticles.

[0039] The product obtained in this embodiment has a specific surface area of ​​150 m², as determined by testing. 2 / g; Figure 1 The EDS image of the product in this embodiment shows that the sample particles are uniformly dispersed and the elements are evenly distributed.

[0040] Example 2 A method for preparing high-entropy oxide nanoparticles, the specific steps of which are as follows: (1) Preparation of metal salt solution: Take 0.01 mol each of ferric nitrate, cobalt nitrate, nickel nitrate, chromium nitrate and manganese nitrate in equal molar ratio, dissolve in 500 mL of deionized water to obtain a mixed metal salt solution; (2) Preparation of precipitant: Prepare a 2 mol / L sodium hydroxide solution as the precipitant; (3) Construction of synergistic dispersion system: Add polymeric dispersant SMA (styrene-maleic anhydride copolymer, 2 wt% of the total mass of the target metal oxide) and ionic surfactant CTAB (hexadecyltrimethylammonium bromide, 0.8 wt% of the total mass of the target metal oxide) to the precipitant solution and stir until completely dissolved to form a precipitant solution containing composite dispersant; (4) Reverse coprecipitation reaction: Under stirring conditions, the metal salt mixed solution prepared in step (1) is slowly added dropwise (dropping rate 1 mL / min) to the precipitant solution containing composite dispersant prepared in step (3) by a constant flow pump. The pH value of the entire reaction system is controlled to be 10, the reaction temperature is 60℃, and the reaction time is 2 hours to obtain a high entropy hydroxide coprecipitation suspension. (5) Washing and drying: After filtering the high-entropy hydroxide coprecipitate suspension, the precipitate was washed with deionized water and ethanol until neutral, and then vacuum dried at 100 °C for 12 hours to obtain a loose high-entropy hydroxide precursor powder. (6) Calcination treatment: The dried precursor was calcined in air at a heating rate of 2 °C / min to 600 °C for 4 hours, and then naturally cooled to obtain (FeCoNiCrMn)3O4 high-entropy oxide nanoparticles. Testing showed that the precipitated elements were uniformly distributed in the product, with a specific surface area of ​​180 m². 2 / g.

[0041] Comparative Example 1 The difference between this comparative example and Example 1 is that no dispersant is added; all other conditions are the same as in Example 1. The specific steps are as follows: (1) Preparation of metal salt solution: Take 0.01 mol each of magnesium nitrate, cobalt nitrate, nickel nitrate, copper nitrate and zinc nitrate in equal molar ratio, dissolve them in 500 mL of deionized water to obtain a mixed metal salt solution; (2) Preparation of precipitant: Prepare a 2 mol / L sodium hydroxide / sodium carbonate (molar ratio 1:2) mixed solution as precipitant; (3) Reverse coprecipitation reaction: Under stirring conditions, the metal salt mixed solution prepared in step (1) is slowly added dropwise (dropping rate 1 mL / min) to the precipitant solution prepared in step (2) by a constant flow pump. The pH value of the entire reaction system is controlled to be 10, the reaction temperature is 60℃, and the reaction time is 2 hours to obtain a high-entropy hydroxide coprecipitation suspension. (4) Washing and drying: After filtering the high-entropy hydroxide coprecipitate suspension, the precipitate was washed with deionized water and ethanol until neutral, and then vacuum dried at 80 °C for 12 hours to obtain a loose high-entropy hydroxide precursor powder. (5) Calcination treatment: The dried precursor was calcined in air at a heating rate of 2 °C / min to 500 °C for 3 hours, and then naturally cooled to obtain MgCoNiCuZnO high-entropy oxide nanoparticles.

[0042] Testing revealed that the product obtained in this comparative example had a particle size of 100-200 nm, exhibited severe agglomeration, highly uneven elemental distribution, and significant elemental segregation, with a specific surface area of ​​only 50 m². 2 / g; Figure 2 This is the EDS image of the product in this comparative example.

[0043] Comparative Example 2 The difference between this comparative example and Example 1 is that only PAA is added, and no ionic surfactant is added; all other conditions are the same as in Example 1. The specific steps are as follows: (1) Preparation of metal salt solution: Take 0.01 mol each of magnesium nitrate, cobalt nitrate, nickel nitrate, copper nitrate and zinc nitrate in equal molar ratio, dissolve them in 500 mL of deionized water to obtain a mixed metal salt solution; (2) Preparation of precipitant: Prepare a 2 mol / L sodium hydroxide / sodium carbonate (molar ratio 1:2) mixed solution as precipitant; (3) Construction of the dispersion system: Add the polymer dispersant PAA (polyacrylic acid, 2.3 wt% of the total mass of the target metal oxide) to the precipitant solution and stir until completely dissolved to form a precipitant solution containing the dispersant; (4) Reverse coprecipitation reaction: Under stirring conditions, the metal salt mixed solution prepared in step (1) is slowly added dropwise (dropping rate 1 mL / min) to the precipitant solution containing dispersant prepared in step (3) by a constant flow pump. The pH value of the entire reaction system is controlled to be 10, the reaction temperature is 60℃, and the reaction time is 2 hours to obtain a high entropy hydroxide coprecipitation suspension. (5) Washing and drying: After filtering the high-entropy hydroxide coprecipitate suspension, the precipitate was washed with deionized water and ethanol until neutral, and then vacuum dried at 80 °C for 12 hours to obtain a loose high-entropy hydroxide precursor powder. (6) Calcination treatment: The dried precursor was calcined in air at a heating rate of 2 °C / min to 500 °C for 3 hours, and then naturally cooled to obtain MgCoNiCuZnO high-entropy oxide nanoparticles.

[0044] Testing revealed that the product obtained in this comparative example had an uneven elemental distribution and a specific surface area of ​​only 120 m². 2 / g.

[0045] Comparative Example 3 The difference between this comparative example and Example 1 is that only SDBS is added, without the addition of a polymer dispersant; all other conditions are the same as in Example 1. The specific steps are as follows: (1) Preparation of metal salt solution: Take 0.01 mol each of magnesium nitrate, cobalt nitrate, nickel nitrate, copper nitrate and zinc nitrate in equal molar ratio, dissolve them in 500 mL of deionized water to obtain a mixed metal salt solution; (2) Preparation of precipitant: Prepare a 2 mol / L sodium hydroxide / sodium carbonate (molar ratio 1:2) mixed solution as precipitant; (3) Construction of the dispersion system: Add ionic surfactant SDBS (2.3 wt% of the total mass of the target metal oxide) to the precipitant solution and stir until completely dissolved to form a precipitant solution containing the dispersant; (4) Reverse coprecipitation reaction: Under stirring conditions, the metal salt mixed solution prepared in step (1) is slowly added dropwise (dropping rate 1 mL / min) to the precipitant solution containing dispersant prepared in step (3) by a constant flow pump. The pH value of the entire reaction system is controlled to be 10, the reaction temperature is 60℃, and the reaction time is 2 hours to obtain a high entropy hydroxide coprecipitation suspension. (5) Washing and drying: After filtering the high-entropy hydroxide coprecipitate suspension, the precipitate was washed with deionized water and ethanol until neutral, and then vacuum dried at 80 °C for 12 hours to obtain a loose high-entropy hydroxide precursor powder. (6) Calcination treatment: The dried precursor was calcined in air at a heating rate of 2 °C / min to 500 °C for 3 hours, and then naturally cooled to obtain MgCoNiCuZnO high-entropy oxide nanoparticles.

[0046] Testing revealed that the product obtained in this comparative example had an uneven elemental distribution and a specific surface area of ​​only 90 m². 2 / g.

[0047] Comparative Example 4 The difference between this comparative example and Example 1 is that step (4) uses forward dropwise addition (the precipitant is added dropwise to the metal salt solution), and the composition of the composite dispersant is the same as in Example 1; step (4) is as follows: Under stirring conditions, the precipitant solution containing dispersant prepared in step (3) is slowly added dropwise (dropping rate 1 mL / min) to the metal salt mixed solution prepared in step (1) by a constant flow pump. The pH value of the entire reaction system is controlled to be 10, the reaction temperature is 60℃, and the reaction time is 2 hours to obtain a high-entropy hydroxide coprecipitation suspension.

[0048] The remaining steps and parameters are the same as in Example 1.

[0049] The product obtained in this comparative example has a relatively uniform elemental distribution and a specific surface area of ​​110 m². 2 / g.

[0050] Comparative Example 5 The difference between this comparative example and Example 1 is that in step (3), PAA (polyacrylic acid, 1.5wt%) in the composite dispersant is replaced with polyethylene glycol, while other conditions are the same as in Example 1.

[0051] The product obtained in this comparative example exhibits some elemental segregation, with a specific surface area of ​​97 m². 2 / g. The hydroxyl groups of polyethylene glycol have a weaker ability to complex metal ions than the carboxyl groups, and are not very effective in regulating the precipitation rate of different metal ions.

[0052] The test results above show that the present invention significantly improves the elemental distribution uniformity and dispersion performance of high-entropy oxide nanoparticles by constructing a composite dispersion system with the synergistic effect of polymeric dispersants and ionic surfactants, and by combining it with a reverse coprecipitation process.

[0053] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A method for preparing high-entropy oxide nanoparticles, characterized in that, Includes the following steps: S1. Dissolve at least five metal salts in water in an equimolar or near-equimolar ratio to obtain a mixed metal salt solution; S2. Prepare a precipitant solution by adding a high molecular weight polymer dispersant and an ionic surfactant with side chains rich in carboxyl or anhydride groups to the precipitant solution to obtain a precipitant solution containing a composite dispersant. S3. Under stirring conditions, the metal salt mixed solution is slowly added dropwise to the precipitant solution containing the composite dispersant to carry out a co-precipitation reaction. After solid-liquid separation, washing, and drying, a high-entropy hydroxide precursor is obtained. S4. The high-entropy hydroxide precursor is calcined to obtain high-entropy oxide nanoparticles.

2. The method for preparing high-entropy oxide nanoparticles according to claim 1, characterized in that, In step S1, the metal salt is selected from nitrates, sulfates, and / or chlorides of transition metals; the transition metals include Fe, Co, Ni, Cr, Mn, Cu, Zn, Mg, and Al; And / or, in step S1, the concentration of the metal salt mixed solution is 0.01~1 mol / L.

3. The method for preparing high-entropy oxide nanoparticles according to claim 1, characterized in that, In step S2, the concentration of the precipitant solution is 0.1~5 mol / L; And / or, the precipitant in the precipitant solution includes at least one of sodium hydroxide, ammonia, sodium carbonate, ammonium bicarbonate, and sodium bicarbonate.

4. The method for preparing high-entropy oxide nanoparticles according to claim 1, characterized in that, In step S2, the amount of the polymer dispersant added is 0.5% to 5% of the total mass of the target metal oxide; the amount of the ionic surfactant added is 0.1% to 2% of the total mass of the target metal oxide.

5. The method for preparing high-entropy oxide nanoparticles according to claim 1, characterized in that, In step S2, the ionic surfactant includes at least one of sodium dodecylbenzenesulfonate and hexadecyltrimethylammonium bromide.

6. The method for preparing high-entropy oxide nanoparticles according to claim 1, characterized in that, In step S2, the polymer dispersant includes at least one of polyacrylic acid, polymethacrylic acid, and styrene-maleic anhydride copolymer.

7. The method for preparing high-entropy oxide nanoparticles according to claim 1, characterized in that, In step S3, the conditions for the coprecipitation reaction are as follows: the reaction temperature is 60~80℃, the reaction time is 2~4 hours, and the pH value of the reaction system is 9~11.

8. The method for preparing high-entropy oxide nanoparticles according to claim 1, characterized in that, In step S3, the drying temperature is 80~100℃ and the drying time is 12~24h.

9. The method for preparing high-entropy oxide nanoparticles according to claim 1, characterized in that, In step S4, the calcination temperature is 400~600℃, the calcination time is 2~4 hours, and the calcination atmosphere is air.

10. A high-entropy oxide nanoparticle, characterized in that, It is prepared by the preparation method of high-entropy oxide nanoparticles according to any one of claims 1 to 9.

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