Preparation method of ferromagnetic spinel type high-entropy oxide material

Abstract

The invention belongs to the technical field of preparation of high-entropy oxides, and discloses a preparation method of a ferromagnetic spinel type high-entropy oxide material, the chemical formula of the ferromagnetic spinel type high-entropy oxide material is (Mn < 0.2 > Fe < 0.2 > Co < 0.2 > Ni < 0.2 > X < 0.2 >) 3O4, X is one of Cr and Cu, and X is one of Ni and Cu. The preparation method comprises the following steps: weighing each metal nitrate according to the stoichiometric ratio of each element in the chemical formula (Mn0. 2Fe0. 2Co0. 2Ni0. 2X0. 2) 3O4, adding the metal nitrate and a template agent into deionized water, dissolving, and carrying out ultrasonic treatment to obtain a precursor solution; drying the precursor solution into sol; and calcining the sol-like precursor to obtain the ferromagnetic spinel type high-entropy oxide material. The high-entropy oxide material is controllable in morphology, shows stable ferrimagnetism, and has huge application prospects in the fields of magnetic catalysis, magnetic storage and the like.

Description

Technical Field

[0001] This invention belongs to the field of high-entropy oxide preparation technology, and relates to a method for preparing a ferrimagnetic spinel-type high-entropy oxide material. Background Technology

[0002] In recent years, the concept of "high entropy" has been extended to various materials, such as high-entroy alloys, high-entroy oxides, high-entroy carbides, high-entroy fluorides, and high-entroy sulfides. High-entroy materials (HEMs) are composed of multiple elements (five or more) in equimolar or near-equimolar ratios and can be applied in multiple fields such as electrodes, ceramic materials, semiconductors, energy storage, and catalysis. High-entroy oxides (HEOs) break away from the traditional design concept of doped oxides, extending the design concept of high-entroy alloys to the oxide field, and are a new type of ceramic material. They are composed of five or more oxides in equimolar or near-equimolar ratios. High-entroy oxide systems, on the one hand, have high configurational entropy, making them prone to forming simple solid solution structures such as rock salt, fluorite, spinel (A3O4), or perovskite (ABO3); on the other hand, because the principal components tend to be randomly arranged, i.e., their chemical composition is in a disordered state, resulting in properties that differ from traditional doped oxides.

[0003] High-entropy nanoparticles, as a cutting-edge branch of the high-entropy materials family, exhibit advantages such as high strength, high stability, and high catalytic activity due to their unique high-entropy effect, lattice distortion effect, and slow diffusion effect. Ferromagnetic high-entropy nanoparticles, possessing both morphological characteristics and magnetic ordering properties, have attracted significant attention in fields such as semiconductors, spintronics, magnetocatalysis, and magnetic refrigeration. Currently, the preparation of high-entropy materials is mainly in particulate form, and nanoparticle sheet structures with ferrimagnetism are not yet widely adopted.

[0004] Because high-entropy materials involve multiple main elements with significantly different physicochemical properties, problems arise such as the difficulty in achieving uniform mixing of elements and the challenge in precisely controlling the structure of nanoparticle sheets, affecting the stability of the material's ferrimagnetic properties. Taking the template method as an example, by designing templates with specific structures, the atoms of high-entropy materials are guided to arrange themselves in an orderly manner on the template surface, thereby forming nanoparticle sheets with specific morphologies and sizes, providing a new direction for the structural control of high-entropy nanoparticle sheets or granular blocks.

[0005] Although significant progress has been made in the preparation of high-entropy nanoparticle sheets or granular masses, challenges remain, such as demanding equipment requirements, stringent reaction conditions, and difficulties in controlling the size, shape, and elemental distribution of nanoparticle sheets. These challenges not only significantly increase production costs but also hinder large-scale industrial production. Some high-temperature, high-pressure synthesis processes place extremely high demands on the high-temperature and high-pressure resistance of the reaction equipment, resulting in high purchase and maintenance costs. Poor size uniformity of the prepared nanoparticle sheets can lead to unstable subferromagnetic properties in practical applications; uneven elemental distribution weakens the unique performance advantages of high-entropy nanoparticle sheets or granular masses. Therefore, there is a need to develop a low-cost preparation method suitable for large-scale production, with controllable nanoparticle structure and stable subferromagnetic properties. Summary of the Invention

[0006] This invention addresses the technical problems of non-uniform size and unstable magnetic properties of high-entropy oxide nanosheets by providing a method for preparing ferrimagnetic spinel-type high-entropy oxide materials. The method employs a sol-gel combined calcination process, which allows for controllable product morphology and exhibits stable ferrimagnetism. This method has great application potential in fields such as magnetic catalysis, magnetic storage, and spintronic devices.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a method for preparing a ferrimagnetic spinel-type high-entropy oxide material, wherein the chemical formula of the ferrimagnetic spinel-type high-entropy oxide material is (Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 X 0.2 X is either Cr or Cu, and the preparation method includes the following steps: a) Arrange the various metal nitrates according to their chemical formulas (Mn) 0.2 Fe 0.2 Co 0.2 Ni 0.2 X 0.2 Weigh the stoichiometric ratio of each element in 3O4, add it together with the template agent to deionized water to dissolve, and sonicate to obtain the precursor solution. b) Dry the precursor solution to a sol state; c) The sol-like precursor is calcined to obtain a ferrimagnetic spinel-type high-entropy oxide material.

[0008] In the above technical solution, each of the metal nitrates is manganese nitrate, ferric nitrate, cobalt nitrate, nickel nitrate, chromium nitrate, or copper nitrate.

[0009] In the above technical solution, the template agent is glucose and glycine.

[0010] In the above technical solution, the ultrasound time is 5 minutes.

[0011] In the above technical solution, the drying temperature is 80 ℃ and the drying time is 5 h.

[0012] In the above technical solution, the calcination temperature is 800 ℃ and the calcination time is 25 min.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) The present invention uses a sol-gel combined calcination method to prepare a five-element spinel-type high-entropy oxide. The product exhibits ferrimagnetism and has a large specific surface area. The synergistic effect of the structure and ferrimagnetic properties enhances the magnetic stability of the material, which has great application prospects in the fields of magnetic catalysis, magnetic storage, and spintronic devices. 2) This invention achieves morphological transformation (from nanosheets to bulk materials) by controlling elements, providing a low-cost path for customized magnetic products. Attached Figure Description

[0014] Figure 1 This is a scanning electron microscope image of the pentagonal spinel high-entropy oxide of Embodiment 1 of the present invention.

[0015] Figure 2 This is an X-ray powder diffraction characterization pattern of the pentagonal spinel high-entropy oxide of Example 1 of the present invention.

[0016] Figure 3 This is an atomic force microscope image of the pentagonal spinel high-entropy oxide of Embodiment 1 of the present invention.

[0017] Figure 4 This is an atomic force microscopy image of the pentagonal spinel high-entropy oxide of Embodiment 1 of the present invention.

[0018] Figure 5 This is a transmission electron microscope image of the pentagonal spinel high-entropy oxide of Embodiment 1 of the present invention.

[0019] Figure 6 This is a graph showing the magnetic susceptibility versus temperature of the pentagonal spinel high-entropy oxide of Example 1 of the present invention.

[0020] Figure 7 This is a curve showing the change in magnetization intensity of the pentagonal spinel high-entropy oxide as a function of magnetic field strength in Example 1 of the present invention.

[0021] Figure 8 This is a scanning electron microscope image of the pentagonal spinel high-entropy oxide of Embodiment 2 of the present invention.

[0022] Figure 9 This is an X-ray powder diffraction characterization pattern of the pentagonal spinel high-entropy oxide of Example 2 of the present invention.

[0023] Figure 10 This is a magnetic susceptibility-temperature curve of the pentagonal spinel high-entropy oxide of Example 2 of the present invention.

[0024] Figure 11 This is a curve showing the change in magnetization intensity of the pentagonal spinel high-entropy oxide as a function of magnetic field strength in Example 2 of the present invention. Detailed Implementation

[0025] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the test methods in the following embodiments are conventional methods.

[0026] Example 1 Preparation of pentagonal spinel-type high-entropy oxide (Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 Cr 0.2 )3O4 Five-element spinel-type high-entropy oxide (Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 Cr 0.2 The specific preparation steps for 3O4 are as follows: a) Weigh out 0.2 mol of 50% manganese nitrate solution, 0.2 mol of ferric nitrate nonahydrate, 0.2 mol of cobalt nitrate hexahydrate, 0.2 mol of nickel nitrate hexahydrate, and 0.2 mol of chromium nitrate nonahydrate. Add them together with glucose (13.7 mmol) and glycine (13.0 mmol) to 30 mL of deionized water and dissolve. Place the solution in an ultrasonic cleaner and sonicate for 5 min to obtain the precursor solution. b) Dry the precursor solution in an 80 ℃ oven until it becomes a sol; c) The sol-like precursor was placed in a muffle furnace and calcined at 800 °C for 25 min to obtain a ferrimagnetic spinel-type high-entropy oxide material.

[0027] The product characterization and results of this embodiment are as follows: Figure 1 Scanning electron microscope images show that the product is a nanosheet formed by uniformly arranged nanoparticles, with a porous structure on the surface; Figure 2 The X-ray diffraction pattern shows that the product is a pure phase with no impurity peaks and has high crystallinity. Figure 3 The atomic force microscope image on the left shows that the product is a nanosheet-like structure. Figure 4The data graph corresponding to the atomic force microscopy image shows that the thickness of the nanosheet is about 3~4 nm. Figure 5 The image is a transmission electron microscope image, and its morphology further indicates that the product is a nanoparticle sheet.

[0028] Figure 6 The magnetic susceptibility-temperature curves show that the zero field-cooled (ZFC) and field-cooled (FC) magnetic susceptibility-temperature curves of this product are bifurcated. The curve trend indicates that there is a magnetic transformation, and the magnetic behavior is affected by temperature and field-cooling history. Low temperature will cause differences in the order of magnetic domains, while high temperature will cause thermal motion to weaken the magnetic order. Figure 7 The curve of magnetization intensity versus magnetic field strength shows that the product exhibits ferrimagnetism at 5K and 300K, and the ferrimagnetism intensity weakens as the temperature increases.

[0029] Example 2 Preparation of pentagonal spinel-type high-entropy oxide (Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 Cu 0.2 )3O4 Five-element spinel-type high-entropy oxide (Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 Cu 0.2 The specific preparation steps for 3O4 are as follows: a) Weigh out 50% manganese nitrate solution (0.2 mol), ferric nitrate nonahydrate (0.2 mol), cobalt nitrate hexahydrate (0.2 mol), nickel nitrate hexahydrate (0.2 mol), and copper nitrate trihydrate (0.2 mol), add them together with glucose (13.7 mmol) and glycine (13.0 mmol) to 30 mL of deionized water to dissolve them, and place them in an ultrasonic cleaner and sonicate for 5 min to obtain the precursor solution; b) Dry the precursor solution in an 80 ℃ oven until it becomes a sol; c) The sol-like precursor was placed in a muffle furnace and calcined at 800 °C for 25 min to obtain a ferrimagnetic spinel-type high-entropy oxide material.

[0030] The product characterization and results of this embodiment are as follows: Figure 8 Scanning electron microscope images show that the product is a blocky structure formed by uniformly arranged nanoparticles with a porous structure on the surface. Figure 9 The X-ray diffraction pattern showed that the product was a pure phase with no impurity peaks and the sample had high crystallinity.

[0031] Figure 10The magnetic susceptibility-temperature curves show that the zero field-cooled (ZFC) and field-cooled (FC) magnetic susceptibility-temperature curves of this product are bifurcated. The curve trend indicates that there is a magnetic transformation, and the magnetic behavior is affected by temperature and field-cooling history. Low temperature will cause differences in the order of magnetic domains, while high temperature will cause thermal motion to weaken the magnetic order. Figure 11 The curves showing the change in magnetization intensity with magnetic field strength indicate that the product exhibits ferrimagnetism at 5K and 300K, and the ferrimagnetism intensity weakens as the temperature increases.

[0032] The embodiments described above are merely preferred embodiments of the present invention and are only used to explain the present invention. They are not intended to limit the scope of the present invention. For those skilled in the art, other implementation methods can be easily made by substitution or modification based on the technical content disclosed in this specification. Therefore, all changes and improvements made on the principle of the present invention should be included within the scope of the patent application of the present invention.

Claims

1. A method for preparing a ferrimagnetic spinel-type high-entropy oxide material, characterized in that, The chemical formula of the ferrimagnetic spinel-type high-entropy oxide material is (Mn) 0.2 Fe 0.2 Co 0.2 Ni 0.2 X 0.2 X is either Cr or Cu, and the preparation method includes the following steps: a) Arrange the various metal nitrates according to their chemical formulas (Mn) 0.2 Fe 0.2 Co 0.2 Ni 0.2 X 0.2 Weigh the stoichiometric ratio of each element in 3O4, add it together with the template agent to deionized water to dissolve, and sonicate to obtain the precursor solution. b) Dry the precursor solution to a sol state; c) The sol-like precursor is calcined to obtain a ferrimagnetic spinel-type high-entropy oxide material.

2. The preparation method according to claim 1, characterized in that, The metal nitrates mentioned are manganese nitrate, ferric nitrate, cobalt nitrate, nickel nitrate, chromium nitrate, or copper nitrate.

3. The preparation method according to claim 1, characterized in that, The template agent is glucose and glycine.

4. The preparation method according to claim 1, characterized in that, The ultrasound duration is 5 minutes.

5. The preparation method according to claim 1, characterized in that, The drying temperature is 80 ℃ and the drying time is 5 hours.

6. The preparation method according to claim 1, characterized in that, The calcination temperature is 800 ℃ and the calcination time is 25 min.

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