Leaf divergent cobalt particle and preparation method thereof

Abstract

The invention provides a leaf divergent cobalt particle and a preparation method thereof, and belongs to the field of material synthesis, and the preparation method comprises the following steps: 1) adding cobalt salt and an alkaline substance into a solvent, and uniformly stirring and mixing to obtain a mixed solution A; 2) adding a reducing agent into the mixed solution A, and uniformly stirring again to obtain a mixed solution B; and (3) transferring the mixed solution B into a high-pressure reaction kettle, carrying out solvothermal reaction, and after the reaction is finished, carrying out magnetic separation on the obtained solid, washing and drying to obtain the leaf-divergent cobalt particles, according to the preparation method, water and ethidene diamine are adopted as solvents, the cobalt particles which are uniform in dispersity and good in morphology control can be obtained without adding other surfactants for regulation, and the specific morphology of the product can be further controlled through original regulation.

Description

Technical Field

[0001] The present invention belongs to the field of material synthesis and preparation, and particularly relates to the synthesis of leaf-divergent cobalt particles and a method for making magnetic composite materials using the same. Background Art

[0002] Cobalt, as a soft magnetic material with high magnetic saturation intensity and low magnetic coercivity, has very broad application prospects in the fields of ceramics, catalysis, magnetic materials, and aerospace. At the same time, the morphology, size, and crystal structure of cobalt particles have a significant impact on its physical and chemical properties. For example, the electromagnetic properties of cobalt magnetic particles with special morphologies (such as chain-like, sheet-like, flower-like, and rice-ear-like) are often superior to those of spherical morphologies. Therefore, the preparation of cobalt particles with special morphologies is of great significance. In the literature "Facile synthesis of leaf-like cobalt microstructures at low temperature

Micro&Nano Letters, 9(2014)312 - 314

International Journal of Hydrogen Energy, 35(2020)17311 - 17319

Materials Chemistry and Physics 91(2005)293–297

[0003] Invention

[0004] The object of the present invention is to propose a synthesis method of leaf-divergent cobalt particles and a method for making magnetic composite materials using the same in view of the problems existing in the background art.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing leaf-divergent cobalt particles, comprising the following steps:

[0007] Step 1: Add cobalt salt and alkaline substance into a solvent, stir and mix evenly to obtain a mixed solution A; wherein, the concentration of the cobalt salt in the mixed solution A is 0.01 - 0.1 mol / L, and the concentration of the alkaline substance is 0.2 - 2 mol / L;

[0008] Step 2: Add a reducing agent to the mixed solution A obtained in Step 1, stir evenly to obtain a mixed solution B, wherein the concentration of the added reducing agent in the mixed solution B is 0.01 - 4 mol / L;

[0009] Step 3: Transfer the mixed solution B obtained in Step 2 to a high-pressure reaction kettle for solvothermal reaction. After the reaction is completed, after magnetic separation, wash alternately with deionized water and alcohol, and then dry in an oven at 60 °C to obtain the leaf-divergent cobalt particles.

[0010] As a preferred mode, the solvent in Step 1 is one or two of deionized water, ethylenediamine, and ethylene glycol.

[0011] As a preferred mode, the cobalt salt in Step 1 is one or several of cobalt sulfate, cobalt acetate, or cobalt chloride;

[0012] As a preferred mode, the alkaline substance in Step 1 is one or several of sodium hydroxide or potassium hydroxide.

[0013] As a preferred mode, the reducing agent in Step 2 is one or several of ascorbic acid, sodium borohydride, sodium hypophosphite, or hydrazine hydrate.

[0014] As a preferred mode, the reaction time of the solvothermal reaction in Step 3 is 2 - 8 h, the reaction temperature is 130 - 200 °C, and the drying time is 6 - 24 h.

[0015] The second object of the present invention is to provide a leaf-divergent cobalt particle obtained by the above preparation method.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. The preparation method of the leaf-divergent cobalt particles provided by the present invention uses water, ethylene glycol, and ethylenediamine as solvents, and cobalt particles with uniform dispersion and good morphology control can be obtained without a surfactant.

[0018] 2. The preparation method of the leaf-divergent cobalt particles provided by the present invention only needs to change the proportion of raw materials to regulate the obtained products.

[0019] 3. The preparation method of the leaf-divergent cobalt particles provided by the present invention has relatively mild reaction conditions, and both the sample yield and purity are relatively good. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Scanning electron microscope image (SEM) of the magnetic cobalt particles prepared in Example 1

[0021] Figure 2 X-ray diffraction pattern (XRD) of the magnetic cobalt particles prepared in Example 1

[0022] Figure 3 Scanning electron microscope image (SEM) of the magnetic cobalt particles prepared in Example 2

[0023] Figure 4 X-ray diffraction pattern (XRD) of the magnetic cobalt particles prepared in Example 2 DETAILED DESCRIPTION OF THE INVENTION

[0024] The following specific examples illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0025] The examples provide a preparation method of leaf-divergent cobalt particles, including the following steps:

[0026] Step 1: Add a cobalt salt and an alkaline substance into a solvent, stir and mix evenly to obtain a mixed solution A; wherein, the concentration of the cobalt salt in the mixed solution A is 0.01 - 0.1 mol / L, and the concentration of the alkaline substance is 0.2 - 2 mol / L;

[0027] Step 2: Add a reducing agent to the mixed solution A obtained in Step 1, stir evenly to obtain a mixed solution B, wherein the concentration of the added reducing agent in the mixed solution B is 0.01 - 4 mol / L;

[0028] Step 3: Transfer the mixed solution B obtained in Step 2 to a high-pressure reaction kettle for solvothermal reaction. After the reaction is completed, after magnetic separation, wash with deionized water and alcohol alternately 3 times, and then dry in an oven at 60 °C to obtain the leaf-divergent cobalt particles.

[0029] In some embodiments, the solvent in Step 1 is one or two of deionized water, ethylenediamine, and ethylene glycol.

[0030] In some embodiments, the cobalt salt described in step 1 is one or more of cobalt sulfate, cobalt acetate, or cobalt chloride;

[0031] In some embodiments, the basic substance described in step 1 is one or more of sodium hydroxide or potassium hydroxide.

[0032] In some embodiments, the reducing agent described in step 2 is one or more of ascorbic acid, sodium borohydride, sodium hypophosphite, or hydrazine hydrate.

[0033] In some embodiments, the reaction time of the solvothermal reaction described in step 3 is 2 - 8 h, the reaction temperature is 130 - 200 °C, and the drying time is 6 - 24 h.

[0034] Example 1

[0035] A method for preparing leaf - diverging cobalt particles, the specific steps are as follows:

[0036] (1) Dissolve 0.119 g of cobalt chloride and 0.1 g of sodium hydroxide in a mixed solution of 10 mL of water and 40 mL of ethylenediamine. After sufficient dissolution by magnetic stirring, a mixed solution A is obtained;

[0037] (2) Add 1 mL of hydrazine hydrate to the above - mentioned mixed solution A, and stir evenly again to obtain a mixed solution B;

[0038] (3) Add the obtained mixed solution B to a 100 - mL high - pressure reaction kettle with a polytetrafluoroethylene lining, react at 130 °C for 4 h, naturally cool to room temperature, and then obtain the product by magnetic separation; the product is washed alternately with deionized water and absolute ethanol for multiple times and then placed in an oven at 60 °C for drying for 6 h to obtain magnetic particles.

[0039] The microscopic morphology of the magnetic cobalt particles prepared in Example 1 of the present invention is as Figure 1 shown. The results show that the microscopic morphology of the prepared sample is leaf - shaped; the X - ray diffraction peak pattern of the prepared magnetic solid cobalt particles is as Figure 2 shown. The results show that the prepared sample is a single - element cobalt with a pure hcp phase structure.

[0040] Example 2

[0041] A method for preparing leaf - diverging cobalt particles, the specific steps are as follows:

[0042] (1) Dissolve 0.119 g of cobalt chloride and 0.1 g of sodium hydroxide in a mixed solution of 10 mL of water and 40 mL of ethylenediamine. After sufficient dissolution by magnetic stirring, a mixed solution A is obtained;

[0043] (2) Add 1 mL of hydrazine hydrate to the above - mentioned mixed solution A, and stir evenly again to obtain a mixed solution B;

[0044] (3) Add the obtained mixed solution B into a 100 mL high-pressure reactor with a polytetrafluoroethylene liner, react at 200 °C for 2 h, naturally cool to room temperature, and then obtain the product by magnetic separation; the product is washed alternately with deionized water and absolute ethanol for multiple times and then dried in an oven at 60 °C for 6 h to obtain magnetic particles.

[0045] The microscopic morphology of the magnetic native cobalt particles prepared in Example 2 of the present invention is as Figure 3 shown. The results show that the microscopic morphology of the prepared sample is in a shape of stacked and divergent leaves; the X-ray diffraction peak pattern of the prepared magnetic solid cobalt particles is as Figure 4 shown. The results show that the prepared sample is elemental cobalt with a pure hcp phase structure.

[0046] The above embodiments merely illustrate the principles and effects of the present invention, rather than limiting the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing leaf-shaped divergent cobalt particles, characterized in that: The following steps are involved: Step 1, adding a cobalt salt and an alkaline substance into a solvent, stirring and mixing them uniformly to obtain a mixed solution A; wherein the concentration of the cobalt salt in the mixed solution A is 0.01 to 0.1 mol / L, and the concentration of the alkaline substance is 0.2 to 2 mol / L; Step 2, adding a reducing agent to the mixed solution A obtained in step 1, stirring evenly to obtain a mixed solution B, wherein the concentration of the added reducing agent in the mixed solution B is 0.01 to 4 mol / L; Step 3, transferring the mixed solution B obtained in step 2 to a high-pressure reactor for solvent thermal reaction. After the reaction is completed, the mixed solution B is subjected to magnetic separation and washed alternately with deionized water and alcohol, and then dried in an oven at 60 degrees Celsius to obtain the leaf-shaped divergent cobalt particles.

2. The method for preparing leaf-shaped divergent cobalt particles according to claim 1, characterized in that: The solvent in step 1 is one or two of deionized water, ethylenediamine, and ethylene glycol.

3. The method for preparing leaf-shaped divergent cobalt particles according to claim 1, characterized in that: The cobalt salt in step 1 is one or more of cobalt sulfate, cobalt acetate or cobalt chloride.

4. The method for preparing leaf-shaped divergent cobalt particles according to claim 1, characterized in that: The alkaline substance in step 1 is one or more of sodium hydroxide or potassium hydroxide.

5. The method for preparing leaf-shaped divergent cobalt particles according to claim 1, characterized in that: The reducing agent in step 2 is one or more of ascorbic acid, sodium borohydride, sodium hypophosphite or hydrazine hydrate.

6. The method for preparing leaf-shaped divergent cobalt particles according to claim 1, characterized in that: The reaction time of the solvent thermal reaction in step 3 is 2 to 8 hours, the reaction temperature is 130 to 200° C., and the drying time is 6 to 24 hours.

7. A leaf-shaped cobalt particle, characterized in that The method is obtained by the preparation method according to any one of claims 1 to 6.

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