Preparation method and application of high-entropy oxide material
High-entropy oxide nanoparticles prepared by co-precipitation and high-temperature calcination ball milling processes have solved the problem of efficient formaldehyde removal at low temperatures, achieving high-efficiency catalyst performance and low by-product formation, making them suitable for industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI UNIV
- Filing Date
- 2024-04-13
- Publication Date
- 2026-06-19
AI Technical Summary
Existing technologies struggle to efficiently remove formaldehyde from indoor air at low temperatures, and traditional high-entropy oxide preparation methods cannot produce nanoscale spherical particles with nanoscale layered surfaces, resulting in low formaldehyde degradation efficiency and numerous byproducts.
High-entropy oxide nanoparticles with an average particle size of 10-20 nm were prepared by co-precipitation combined with high-temperature calcination and ball milling. These nanoparticles have high specific surface area and oxygen defects. High-entropy hydroxides were formed by co-precipitation, followed by high-temperature calcination and ball milling to obtain high-entropy oxide materials with multi-dimensional papillary catalytic surfaces.
It significantly improves the efficiency of formaldehyde catalysis by low-temperature plasma, reduces the generation of by-products, and the preparation method is simple and easy to control, making it suitable for industrial applications.
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Figure CN118341439B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of functional nanomaterials technology, specifically to a method for preparing and applying high-entropy oxide materials. Background Technology
[0002] Formaldehyde (HCHO), a major indoor air pollutant, is widely known for its harmful effects on human health and the environment, such as irritation to the eyes, nose, and throat, allergic asthma, lung damage, and even cancer. Nonthermal plasma (NTP) is considered a promising method for removing HCHO due to its non-equilibrium nature, fast reaction speed, low energy cost, and unique ability to initiate physical and chemical reactions at low temperatures. When plasma is used alone to discharge in an air-like mixture, the formation of O3 is unavoidable. Since O3 also contributes to poor indoor air quality, it should be removed from the treated gas. On the other hand, although O3 itself is a relatively weak oxidant in NTPs compared to •O and •OH radicals, there is great potential to rationally utilize the oxidizing power of O3 by tandem NTPs with catalysts. It is necessary to develop catalysts that can synergistically work with NTPs to improve the removal efficiency of gaseous pollutants, increase the selectivity of desired end products, and minimize the formation of unwanted byproducts.
[0003] High entropy oxides (HEOs), with their unique structural features, customizable elemental composition, and associated tunable functions, have emerged as potential candidates for next-generation catalysts in recent years through entropy engineering. The synthesis methods are directly related to the structural properties of HEO catalysts. HEOs are frequently used in catalysis-related applications in the form of nanoparticles and nanoporous structures to optimize their surface area and active sites, thereby improving catalytic performance. However, traditional HEO preparation methods (solid-state synthesis) rely on high-temperature crystallization, which limits the size of the powder particles (sintering is unavoidable) and prevents them from forming nanoparticles. Atomized spray pyrolysis and flame spray pyrolysis technologies can reduce the size of powder particles by shortening the residence time of the powder at high temperatures, but agglomeration inevitably occurs during the synthesis process.
[0004] Therefore, existing technologies all use high temperatures, which cannot produce nanoscale, papillary spherical particles with nanoscale stacked surfaces. Their performance cannot meet the requirements for efficient degradation of HCHO materials at low temperatures. Summary of the Invention
[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a method for preparing high-entropy oxide materials and their applications. By simultaneously improving the formulation and preparation process, a more advanced synthesis method is adopted to achieve rapid low-temperature synthesis of high-entropy oxide nanoparticles. Furthermore, the particle size of most high-entropy oxide particles is controlled to be within 10 nm to 20 nm, while also possessing high specific surface area and oxygen defects. This can solve the technical problems of low catalyst degradation efficiency and numerous by-products in low-temperature plasma synergistic catalysis in existing technologies.
[0006] To achieve the above-mentioned technical objectives, the present invention provides the following technical solution:
[0007] A method for preparing a high-entropy oxide material firstly employs a co-precipitation method, in which a mixed metal salt solution is precipitated in a high-concentration sodium hydroxide solution to form a high-entropy hydroxide. The high-entropy hydroxide is then collected, subjected to high-temperature calcination and ball milling, to obtain spherical high-entropy oxide particles with an average particle size of 15 nm and possessing both high specific surface area and oxygen defects.
[0008] The method for preparing the high-entropy oxide material includes the following steps:
[0009] S1. Dissolve and dilute a mixture of manganese salt, copper salt, cobalt salt, iron salt, nickel salt, and cerium salt to obtain a combined metal precursor solution;
[0010] S2. Add a high-concentration sodium hydroxide solution to a polytetrafluoroethylene petri dish;
[0011] S3. The metal precursor solution is dropped dropwise into a polytetrafluoroethylene petri dish to obtain high-entropy hydroxide.
[0012] S4. Collect the high-entropy hydroxide, wash it until neutral, and place it in an oven to dry.
[0013] S5. The high-entropy hydroxide is calcined at 400-800℃ to obtain a high-entropy oxide;
[0014] S6. The high-entropy oxide is placed in a planetary ball mill and ball-milled to obtain nano-high-entropy oxide particles with an average particle size of 15 nm and high specific surface area and oxygen defects.
[0015] In step S1, the manganese salt is a 50wt% manganese nitrate solution, the copper salt is copper nitrate trihydrate, the cobalt salt is cobalt nitrate hexahydrate, the iron salt is ferric nitrate nonahydrate, the nickel salt is nickel nitrate hexahydrate, and the cerium salt is cerium nitrate hexahydrate.
[0016] In step S1, the first combined metal precursor solution is prepared by a 50wt% manganese nitrate solution with a metal ion molar ratio of 1:1:1:1:1, copper nitrate trihydrate, cobalt nitrate hexahydrate, ferric nitrate nonahydrate, and nickel nitrate hexahydrate; the second combined metal precursor solution is prepared by a 50wt% manganese nitrate solution with a metal ion molar ratio of 1:1:1:1:1, copper nitrate trihydrate, cobalt nitrate hexahydrate, ferric nitrate nonahydrate, and cerium nitrate hexahydrate.
[0017] In step S2, the concentration of sodium hydroxide is 10-20 wt%.
[0018] In step S4, the oven drying temperature is 60°C and the drying time is 12 hours.
[0019] In step S6, the planetary ball mill rotates at 300 rpm and the milling time is 12 h.
[0020] A high-entropy oxide material is prepared by the aforementioned preparation method; the high-entropy oxide material has an average particle size of 15 nm and simultaneously possesses high specific surface area and oxygen defects; multiple high-entropy oxide material particles are arranged to form a catalytic surface with multi-dimensional papillary structures.
[0021] Application of the aforementioned high-entropy oxide material in low-temperature plasma catalysis of HCHO.
[0022] Compared with the prior art, the beneficial effects of the present invention include:
[0023] 1. The preparation method of high-entropy oxide material provided by the present invention mainly involves mixing manganese salt, copper salt, cobalt salt, iron salt, nickel salt and cerium salt, and then reacting them in a polytetrafluoroethylene petri dish containing high concentration of sodium hydroxide to form high-entropy hydroxide; calcining the high-entropy hydroxide at 400~600℃ to obtain high-entropy oxide, and then ball milling it with a planetary ball mill to obtain high-entropy oxide particulate material with nanoscale microstructure, high specific surface area and oxygen defects, and controlling the particle size of most high-entropy oxide particles to be within 10 nm to 20 nm.
[0024] 2. The high-entropy oxide material provided by this invention, due to its nanoscale, high specific surface area and microstructure with more oxygen defects, can significantly improve the efficiency of low-temperature plasma co-catalytic degradation of formaldehyde when applied to formaldehyde, while reducing the generation of by-products.
[0025] 3. The preparation method provided by this invention is simple in steps, easy to control, has stable quality, and is easy to industrialize. Attached Figure Description
[0026] Figure 1 The image shows the XRD pattern of the (MnCuCoFeNi)3O4 material prepared in Example 1 of this invention.
[0027] Figure 2 This is a scanning electron microscope image of the (MnCuCoFeNi)3O4 material prepared in Example 1 of the present invention.
[0028] Figure 3 This is a transmission electron microscope image of the (MnCuCoFeNi)3O4 material prepared in Example 1 of the present invention.
[0029] Figure 4 This is a transmission electron microscope image of the (MnCuCoFeCe)3O4 material prepared in Example 1 of the present invention.
[0030] Figure 5 The diagram shows the low-temperature plasma synergistic catalytic activity of HCHO for the (MnCuCoFeNi)3O4 material prepared in Example 1 of this invention and the materials prepared in Comparative Examples 1 and 2.
[0031] Figure 6 The graph shows the yield of O3 byproducts in low-temperature plasma synergistic catalysis of the (MnCuCoFeNi)3O4 material prepared in Example 1 of this invention and the materials prepared in Comparative Examples 1 and 2.
[0032] Figure 7 NO is a low-temperature plasma-assisted catalytic byproduct of the (MnCuCoFeNi)3O4 material prepared in Example 1 of this invention and the materials prepared in Comparative Examples 1 and 2. x Production chart. Detailed Implementation
[0033] The present invention will now be described in further detail with reference to the accompanying drawings and several specific embodiments, so that those skilled in the art can implement it based on the description.
[0034] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.
[0035] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.
[0036] Basic Implementation
[0037] The method for preparing high-entropy oxide materials provided in this embodiment first employs a co-precipitation method, precipitating a mixed metal salt solution in high-concentration sodium hydroxide to form high-entropy hydroxide. Then, the high-entropy hydroxide is collected, subjected to high-temperature calcination and ball milling, to obtain spherical high-entropy oxide particle materials with an average particle size of 15 nm (most high-entropy oxide particles have a particle size between 10 nm and 20 nm), and possessing both high specific surface area and oxygen defects. The method includes the following steps:
[0038] S1. Dissolve and dilute a mixture of manganese salt, copper salt, cobalt salt, iron salt, nickel salt, and cerium salt to obtain a combined metal precursor solution;
[0039] Wherein, the manganese salt is a 50wt% manganese nitrate solution, the copper salt is copper nitrate trihydrate, the cobalt salt is cobalt nitrate hexahydrate, the iron salt is ferric nitrate nonahydrate, the nickel salt is nickel nitrate hexahydrate, and the cerium salt is cerium nitrate hexahydrate.
[0040] The first metal precursor solution is made of a 50wt% manganese nitrate solution with a metal ion molar ratio of 1:1:1:1:1, copper nitrate trihydrate, cobalt nitrate hexahydrate, ferric nitrate nonahydrate, and nickel nitrate hexahydrate.
[0041] The second metal precursor solution is prepared by a 50wt% manganese nitrate solution with a metal ion molar ratio of 1:1:1:1:1, copper nitrate trihydrate, cobalt nitrate hexahydrate, ferric nitrate nonahydrate, and cerium nitrate hexahydrate.
[0042] S2. Add a high-concentration sodium hydroxide solution (10-20 wt%) to a polytetrafluoroethylene (PTFE) petri dish.
[0043] S3. The metal precursor solution is dropped dropwise into a polytetrafluoroethylene petri dish to obtain high-entropy hydroxide.
[0044] S4. Collect the high-entropy hydroxide, wash it until neutral, and place it in an oven to dry. The oven drying temperature is 60℃ and the time is 12h.
[0045] S5. The high-entropy hydroxide is calcined at 400-800℃ to obtain a high-entropy oxide;
[0046] S6. The high-entropy oxide was placed in a planetary ball mill and milled at a speed of 300 rpm for 12 hours to obtain nano-high-entropy oxide particles with an average particle size of 15 nm and high specific surface area and oxygen defects.
[0047] A high-entropy oxide material is prepared by the aforementioned preparation method; the high-entropy oxide material has an average particle size of 15 nm and simultaneously possesses high specific surface area and oxygen defects; multiple high-entropy oxide material particles are arranged to form a catalytic surface with multi-dimensional papillary structures.
[0048] The application of the high-entropy oxide material in low-temperature plasma catalysis of HCHO.
[0049] To more clearly understand the purpose, technical solution, and advantages of this invention, the following detailed description is provided based on the basic embodiments and in conjunction with several specific embodiments. The specific data used in the specific examples described herein are for illustrative purposes only and are not intended to limit the scope of the invention.
[0050] Example 1
[0051] See appendix Figure 1-7 The preparation method and application of the high-entropy oxide material provided in this example are basically the same as those in the aforementioned basic embodiments, except that:
[0052] The high-entropy oxide material is prepared by the following steps:
[0053] S1. Mix 0.002 mol of 50% manganese nitrate solution, 0.002 mol of copper nitrate trihydrate, 0.002 mol of cobalt nitrate hexahydrate, 0.002 mol of ferric nitrate nonahydrate, and 0.002 mol of nickel nitrate hexahydrate evenly, and dilute to volume in a 10 ml volumetric flask to obtain a mixed metal salt solution.
[0054] S2. Add 10% sodium hydroxide solution to a polytetrafluoroethylene petri dish;
[0055] S3. The metal precursor solution is dropped dropwise into a polytetrafluoroethylene petri dish to obtain high-entropy hydroxide.
[0056] S4. Collect the high-entropy hydroxide, wash it until neutral, and dry it in an oven at 60°C for 12 hours.
[0057] S5. The high-entropy hydroxide is calcined at 400°C to obtain a high-entropy oxide;
[0058] S6. The high-entropy oxide is placed in a planetary ball mill and milled at 300 rpm for 12 hours to obtain a high-entropy oxide material with a high specific surface area.
[0059] observe Figure 1 It can be seen that (MnCuCoFeNi)3O4 was successfully prepared in this embodiment. From Figure 2 , 3It can be seen that the average particle size of the nanoparticles prepared in this embodiment is 15 nm, and the size of the nanoparticles exhibits a diverse distribution. Through particle size analysis of the high-entropy oxide material, the diameter of most particles is concentrated between 10 nm and 20 nm, of which about 60% of the particles have a diameter of around 15 nm. Moreover, it also has a high specific surface area and oxygen defects.
[0060] Example 2
[0061] The preparation method and application of the high-entropy oxide material provided in this example are basically the same as those in the aforementioned basic example 1, except that:
[0062] The high-entropy oxide material is specifically prepared by the following steps:
[0063] S1. Mix 0.002 mol of 50% manganese nitrate solution, 0.002 mol of copper nitrate trihydrate, 0.002 mol of cobalt nitrate hexahydrate, 0.002 mol of ferric nitrate nonahydrate, and 0.002 mol of nickel nitrate hexahydrate evenly, and dilute to volume in a 10 ml volumetric flask to obtain a mixed metal salt solution.
[0064] S2. Add 10% sodium hydroxide solution to a polytetrafluoroethylene petri dish;
[0065] S3. The metal precursor solution is dropped dropwise into a polytetrafluoroethylene petri dish to obtain high-entropy hydroxide.
[0066] S4. Collect the high-entropy hydroxide, wash it until neutral, and dry it in an oven at 60°C for 12 hours.
[0067] S5. The high-entropy hydroxide is calcined at 600°C to obtain a high-entropy oxide;
[0068] S6. The high-entropy oxide is placed in a planetary ball mill and milled at 300 rpm for 12 hours to obtain a high-entropy oxide material with a high specific surface area.
[0069] Example 3
[0070] The preparation method and application of the high-entropy oxide material provided in this example are basically the same as those in the aforementioned basic examples 1-2, except that:
[0071] The high-entropy oxide material proposed in this example is prepared by the following steps:
[0072] S1. Mix 0.002 mol of 50% manganese nitrate solution, 0.002 mol of copper nitrate trihydrate, 0.002 mol of cobalt nitrate hexahydrate, 0.002 mol of ferric nitrate nonahydrate, and 0.002 mol of nickel nitrate hexahydrate evenly, and dilute to volume in a 10 ml volumetric flask to obtain a mixed metal salt solution.
[0073] S2. Add 20% sodium hydroxide solution to a polytetrafluoroethylene petri dish;
[0074] S3. The metal precursor solution is dropped dropwise into a polytetrafluoroethylene petri dish to obtain high-entropy hydroxide.
[0075] S4. Collect the high-entropy hydroxide, wash it until neutral, and dry it in an oven at 60°C for 12 hours.
[0076] S5. The high-entropy hydroxide is calcined at 400°C to obtain a high-entropy oxide;
[0077] S6. The high-entropy oxide is placed in a planetary ball mill and milled at 300 rpm for 12 hours to obtain a high-entropy oxide material with a high specific surface area.
[0078] Example 4
[0079] The preparation method and application of the high-entropy oxide material provided in this example are basically the same as those in the aforementioned basic examples 1-3, except that:
[0080] The high-entropy oxide material proposed in this example is prepared by the following steps:
[0081] S1. Mix 0.002 mol of 50% manganese nitrate solution, 0.002 mol of copper nitrate trihydrate, 0.002 mol of cobalt nitrate hexahydrate, 0.002 mol of ferric nitrate nonahydrate, and 0.002 mol of nickel nitrate hexahydrate evenly, and dilute to volume in a 10 ml volumetric flask to obtain a mixed metal salt solution.
[0082] S2. Add 20% sodium hydroxide solution to a polytetrafluoroethylene petri dish;
[0083] S3. The metal precursor solution is dropped dropwise into a polytetrafluoroethylene petri dish to obtain high-entropy hydroxide.
[0084] S4. Collect the high-entropy hydroxide, wash it until neutral, and dry it in an oven at 60°C for 12 hours.
[0085] S5. The high-entropy hydroxide is calcined at 600°C to obtain a high-entropy oxide;
[0086] S6. The high-entropy oxide is placed in a planetary ball mill and milled at 300 rpm for 12 hours to obtain a high-entropy oxide material with a high specific surface area.
[0087] Example 5
[0088] The preparation method and application of the high-entropy oxide material provided in this example are basically the same as those in the aforementioned basic examples 1-4, except that:
[0089] The high-entropy oxide material proposed in this example is prepared by the following steps:
[0090] S1. Mix 0.002 mol of 50% manganese nitrate solution, 0.002 mol of copper nitrate trihydrate, 0.002 mol of cobalt nitrate hexahydrate, 0.002 mol of ferric nitrate nonahydrate, and 0.002 mol of cerium nitrate hexahydrate evenly, and dilute to volume in a 10 ml volumetric flask to obtain a mixed metal salt solution.
[0091] S2. Add 10% sodium hydroxide solution to a polytetrafluoroethylene petri dish;
[0092] S3. The metal precursor solution is dropped dropwise into a polytetrafluoroethylene petri dish to obtain high-entropy hydroxide.
[0093] S4. Collect the high-entropy hydroxide, wash it until neutral, and dry it in an oven at 60°C for 12 hours.
[0094] S5. The high-entropy hydroxide is calcined at 400°C to obtain a high-entropy oxide;
[0095] S6. The high-entropy oxide is placed in a planetary ball mill and milled at 300 rpm for 12 hours to obtain a high-entropy oxide material with a high specific surface area.
[0096] from Figure 4 As can be seen, the high-entropy oxide material prepared in this embodiment is layered with a diameter of nm.
[0097] Comparative Example 1
[0098] This comparative example presents a catalyst prepared by the following steps:
[0099] S1. Mix 0.002 mol of 50% manganese nitrate solution, 0.002 mol of copper nitrate trihydrate, 0.002 mol of cobalt nitrate hexahydrate, 0.002 mol of ferric nitrate nonahydrate, and 0.002 mol of nickel nitrate hexahydrate evenly, and dilute to volume in a 10 ml volumetric flask to obtain a mixed metal salt solution.
[0100] S2. Add 2% sodium hydroxide solution to a polytetrafluoroethylene beaker;
[0101] S3. The metal precursor solution is dropped dropwise into a polytetrafluoroethylene petri dish to obtain high-entropy hydroxide, and the reaction is carried out for 30 min.
[0102] S4. Collect the high-entropy hydroxide, wash it until neutral, and dry it in an oven at 60°C for 12 hours.
[0103] S5. The high-entropy hydroxide is calcined at 400°C to obtain a high-entropy oxide;
[0104] S6. The high-entropy oxide is placed in a planetary ball mill and milled at 300 rpm for 12 hours to obtain a high-entropy oxide material with a high specific surface area.
[0105] Comparative Example 2
[0106] This comparative example presents a catalyst prepared by the following steps:
[0107] S1. Mix 0.002 mol of 50% manganese nitrate solution, 0.002 mol of copper nitrate trihydrate, 0.002 mol of cobalt nitrate hexahydrate, 0.002 mol of ferric nitrate nonahydrate, and 0.002 mol of nickel nitrate hexahydrate evenly, and dilute to volume in a 10 ml volumetric flask to obtain a mixed metal salt solution.
[0108] S2. Add 2% sodium hydroxide solution to a polytetrafluoroethylene beaker;
[0109] S3. The metal precursor solution is dropped dropwise into a polytetrafluoroethylene petri dish to obtain high-entropy hydroxide, and the reaction is carried out for 30 min.
[0110] S4. Collect the high-entropy hydroxide, wash it until neutral, and dry it in an oven at 60°C for 12 hours.
[0111] S5. The high-entropy hydroxide is calcined at 600°C to obtain a high-entropy oxide;
[0112] S6. The high-entropy oxide is placed in a planetary ball mill and milled at 300 rpm for 12 hours to obtain a high-entropy oxide material with a high specific surface area.
[0113] The low-temperature plasma synergistic catalytic performance of the high-entropy oxide material prepared in this invention was tested in a self-made glass gas chamber. A 240W adjustable plasma discharge plate was used to generate plasma. HCHO was generated by heating formalin within the chamber, with a concentration of 10 ppm. The O3 concentration in the mixed gas inside the chamber was detected using an ozone detector. The vacuum pump flow rate was calibrated using a soap flow meter to control the gas flow rate at 500 ml / min. The gas extracted by the vacuum pump was brought to the probe of a NOx gas detector to obtain the NOx concentration in the mixed gas inside the chamber. Simultaneously, to collect the HCHO concentration, the gas pumped by the vacuum pump was passed into a stoppered graduated test tube used for measuring HCHO using acetylacetone spectrophotometry. Gas data inside the chamber was collected every 30 minutes. Figure 5 It can be seen that, Figure 5 The (MnCuCoFeNi)3O4 high-entropy oxide material prepared in Example 1 using 10% NaOH / HEO-400 achieved a formaldehyde conversion efficiency of 98% under a 240W plasma discharge sheet; while the conversion rate of Comparative Example 1 was only 91%; and the conversion rate of Comparative Example 2 was only 69%. The high-entropy oxide material of Example 1 has relatively better low-temperature plasma synergistic catalytic performance.
[0114] from Figure 6 It can be seen that, Figure 6 The (MnCuCoFeNi)3O4 high-entropy oxide material prepared using 10% NaOH / HEO-400 in Example 1 showed that the byproduct O3 was only 2450 μg / m³ under a 240 W plasma discharge. 3 ); while the O3 in Comparative Example 1 has 6680 (ug / m³) 3 ); Comparative Example 2 O3 has 8090 (ug / m³) 3 The high-entropy oxide material in Example 1 exhibits relatively better O3 degradation performance.
[0115] from Figure 7 It can be seen that, Figure 7 The (MnCuCoFeNi)3O4 high-entropy oxide material prepared in Example 1 using 10% NaOH / HEO-400 exhibited a NOx byproduct of only 0.69 ppm under a 240 W plasma discharge sheet; while Comparative Example 1 showed 3.74 ppm NOx and Comparative Example 2 showed 4.07 ppm NOx. The high-entropy oxide material of Example 1 demonstrates relatively better NOx degradation performance.
[0116] Other beneficial effects:
[0117] This invention relates to a high-entropy oxide material (MnCuCoFeNi)3O4 prepared using a high-entropy strategy. This material is nanosphere-shaped, has a large specific surface area and abundant oxygen defects, which improves the performance of the catalyst in low-temperature plasma synergistic catalysis, increases the formaldehyde elimination rate, and reduces the emission of by-products.
[0118] The method for preparing (MnCuCoFeNi)3O4 high-entropy oxide materials provided by this invention is simple in steps, easy to control, produces stable quality, and is easy to industrialize.
[0119] The product of this invention is applied to low-temperature plasma synergistic catalysis, and has broad application prospects and huge generation potential in the field of low-energy and environmentally friendly technology.
[0120] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A method for preparing a high-entropy oxide material, characterized in that, First, a co-precipitation method is used to precipitate a mixed metal salt solution in sodium hydroxide with a concentration of 10-20 wt% to form a high-entropy hydroxide. Then, the high-entropy hydroxide is collected, calcined at high temperature and ball-milled to obtain spherical high-entropy oxide particles with an average particle size of 15 nm and high specific surface area and oxygen defects. The mixed metal salt solution is either a first combination of metal precursor solutions or a second combination of metal precursor solutions. The first combination of metal precursor solutions is prepared by a 50wt% manganese nitrate solution, copper nitrate trihydrate, cobalt nitrate hexahydrate, ferric nitrate nonahydrate, and nickel nitrate hexahydrate, with a metal ion molar ratio of 1:1:1:1:
1. The second combination of metal precursor solutions is prepared by a 50wt% manganese nitrate solution, copper nitrate trihydrate, cobalt nitrate hexahydrate, ferric nitrate nonahydrate, and cerium nitrate hexahydrate, with a metal ion molar ratio of 1:1:1:1:
1.
2. The method for preparing the high-entropy oxide material according to claim 1, characterized in that, It includes the following steps: S1. Mix and dissolve the metal salts and make up the volume to obtain the corresponding combined metal precursor solution; S2. Add a 10-20 wt% sodium hydroxide solution to a polytetrafluoroethylene petri dish; S3. The metal precursor solution is dropped dropwise into a polytetrafluoroethylene petri dish to obtain high-entropy hydroxide. S4. Collect the high-entropy hydroxide, wash it until neutral, and place it in an oven to dry. S5. The high-entropy hydroxide is calcined at 400-800℃ to obtain a high-entropy oxide; S6. The high-entropy oxide is placed in a planetary ball mill and ball-milled to obtain nano-high-entropy oxide particles with an average particle size of 15 nm and high specific surface area and oxygen defects.
3. The method for preparing the high-entropy oxide material according to claim 2, characterized in that, In step S4, the oven drying temperature is 60°C and the drying time is 12 hours.
4. The method for preparing the high-entropy oxide material according to claim 2, characterized in that, In step S6, the planetary ball mill rotates at 300 rpm and the milling time is 12 h.
5. A high-entropy oxide material, characterized in that, It is prepared by the preparation method according to any one of claims 1-4.
6. The high-entropy oxide material according to claim 5, characterized in that, The high-entropy oxide material has an average particle size of 15 nm and also has a high specific surface area and oxygen defects; multiple high-entropy oxide material particles are arranged to form a catalytic surface with multi-dimensional papillary structure.
7. The application of a high-entropy oxide material as described in any one of claims 5 or 6 in low-temperature plasma catalysis of HCHO.