CN112939069A - Preparation method of barium titanate @ titanium dioxide nano powder with uniform coating structure - Google Patents
Preparation method of barium titanate @ titanium dioxide nano powder with uniform coating structure Download PDFInfo
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- CN112939069A CN112939069A CN202110378366.2A CN202110378366A CN112939069A CN 112939069 A CN112939069 A CN 112939069A CN 202110378366 A CN202110378366 A CN 202110378366A CN 112939069 A CN112939069 A CN 112939069A
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- C01G23/006—Alkaline earth titanates
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Abstract
The invention discloses a preparation method of barium titanate @ titanium dioxide nanopowder with a uniform coating structure. Next, tetrabutyl titanate (Ti (C)) was used4H9O)4) Hydrolyzing to prepare the titanium dioxide coating layer. And finally, calcining the prepared powder, removing organic matters and simultaneously improving the crystallinity of the titanium dioxide. The method has simple process and obvious effect, and the prepared barium titanate @ titanium dioxide nano powder has a titanium dioxide shell layer with uniform thickness and complete appearance.
Description
Technical Field
The invention relates to a preparation method of barium titanate @ titanium dioxide nano powder with a uniform coating structure, and belongs to the field of inorganic nonmetallic dielectric materials.
Background
The core-shell structure is an orderly assembled structure formed by coating one nano material on the surface of the other nano material through chemical bonds or other interactions, and the components and the proportion of the core shell can be designed according to functional requirements so as to obtain the optimal performance. The unique advantages of the core-shell structure enable the core-shell structure to play an important role in a plurality of fields such as catalysis, magnetism, room temperature multiferroics, electrochemical energy storage, bioengineering and the like.
The present study was focused on obtaining titanium dioxide coated barium titanate nanopowders with uniform thickness and complete morphology. Barium titanate is a very important dielectric material, has good dielectric properties, ferroelectricity, piezoelectricity, nonlinear optical properties and the like, and is widely applied to the fields of microelectronics, photoelectrons, integrated optics and the like. The specific shell structure is designed on the surface of the barium titanate, so that the agglomeration effect of the nano powder can be reduced, and the sintering characteristic, the electrical property and the like of the nano powder can be further regulated and controlled. Therefore, it is very significant to develop a method for preparing barium titanate-based core-shell structure nano powder with simple process, low cost and excellent coating effect.
Disclosure of Invention
The invention provides a preparation method of barium titanate @ titanium dioxide nano powder with a uniform coating structure, which is obtained by modifying the surface of barium titanate with glucose, and comprises the following steps:
(1) sequentially adding glucose and barium titanate nanopowder into deionized water, and performing ultrasonic dispersion to obtain barium titanate-glucose aqueous solution;
(2) carrying out hydrothermal reaction on the barium titanate-glucose aqueous solution to obtain barium titanate with the surface coated with an amorphous carbon layer as modified barium titanate nano powder;
(3) dispersing the modified barium titanate nano powder into absolute ethyl alcohol to obtain a barium titanate suspension;
(4) taking Ti (C)4H9O)4Dissolving the barium titanate powder in an absolute ethyl alcohol solvent, then dropwise adding the solution into the barium titanate suspension in the step (3), stirring at room temperature, then standing to remove supernatant liquid, and drying to obtain powder;
(5) and (4) calcining the powder in the step (4), removing organic matters and simultaneously improving the crystallinity of the titanium dioxide.
Preferably, in the step (1), the mass ratio of barium titanate to glucose is 1:1 to 1: 1.2.
Preferably, in the step (2), the hydrothermal reaction is carried out at a temperature of 150 to 170 ℃ for a holding time of 5 to 7 hours.
Preferably, in the step (3), to ensure uniform dispersion of the nanoparticles, 1g of glucose-modified barium titanate nanopowder is dispersed in at least 120mL of anhydrous ethanol.
Preferably, in the step (4), in order to control the hydrolysis reaction rate so as to obtain a uniform coating layer, 1mL of Ti (C)4H9O)4At least 9mL of absolute ethyl alcohol is needed as a solvent, and the dropping speed of the mixed solution is not more than 0.02 mm/s.
Preferably, the temperature of the calcination in the step (5) is 500 to 550 ℃.
The invention has the beneficial effects that: compared with the prior art, the preparation method has the advantages that the preparation process is simple, the process is easy to control, and the prepared barium titanate @ titanium dioxide nano powder presents a titanium dioxide shell layer with very uniform thickness and very complete appearance, and is different from the method that Ti (C) is directly utilized without adopting glucose to carry out surface modification on barium titanate4H9O)4The appearance of the shell layer of the titanium dioxide prepared by hydrolysis is disordered and irregular. In addition, a large number of development experiments show that after the hydrothermal reaction of glucose, a layer of amorphous carbon is coated on the surface of barium titanate, and the amorphous carbon layer contains more hydroxyl, carboxyl and the likeThe functional group not only facilitates the dispersion of barium titanate in the solution, but also provides an attachment site for the deposition of titanium dioxide, thereby obtaining the barium titanate @ titanium dioxide nano powder with a uniform coating structure.
The features and advantages of the present invention will be described in detail by embodiments in conjunction with the accompanying drawings.
Drawings
FIG. 1 is a TEM photograph of a barium titanate @ titanium dioxide powder prepared in example 1;
FIG. 2(a) is a photograph of barium titanate @ titanium dioxide prepared in example 1 in STEM mode, (b) is the result of EDS line scan analysis of the AB line segment;
FIG. 3 is a powder XRD diffraction pattern of pure barium titanate powder and the barium titanate @ titanium dioxide powder prepared in example 1 after calcination at 500 ℃;
FIG. 4 is a TEM photograph of the barium titanate @ titanium dioxide powder prepared in example 2;
FIG. 5 is a TEM photograph of the barium titanate @ titanium dioxide powder prepared in example 3;
FIG. 6 is a TEM photograph of the barium titanate @ titanium dioxide powder prepared in comparative example 1.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood, however, that the description herein of specific embodiments is only intended to illustrate the invention and not to limit the scope of the invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.
The first embodiment is as follows:
(1) adding 3.0g of glucose into 40mL of deionized water, stirring until the solution is clear, adding 3.0g of barium titanate nano powder, and ultrasonically oscillating for 1 hour to uniformly disperse the barium titanate nano powder in the glucose aqueous solution;
(2) and pouring the ultrasonically dispersed barium titanate-glucose aqueous solution into a reaction kettle for hydrothermal reaction, wherein the temperature of the hydrothermal reaction is 150 ℃, and the heat preservation time is 7 hours. Cooling along with the furnace, removing the upper brown liquid, washing the upper brown liquid for 3 times by using absolute ethyl alcohol, coating an amorphous carbon layer on the surface of the barium titanate, and changing the color of the powder from original white to coffee;
(3) dispersing 0.25g of glucose-modified barium titanate nano powder into 30mL of absolute ethyl alcohol, carrying out ultrasonic oscillation for 1 hour, and then carrying out magnetic stirring at room temperature;
(4) take 1mL of Ti (C)4H9O)4Dissolving the barium titanate powder in 9mL of absolute ethyl alcohol solvent, sucking the mixed solution by using a syringe, slowly dropwise adding the mixed solution into the barium titanate suspension which is magnetically stirred in the step (3) at the speed of 0.02mm/s, after dropwise adding, continuously magnetically stirring at room temperature for 3 hours, then standing to remove supernatant liquid, placing the supernatant liquid in an oven at 60 ℃ for drying, and obtaining an SEM photo of the dried powder which is shown in figure 1 and has a very uniform core-shell structure; FIG. 2 is a line scan of the powder further identifying the shell material as titanium dioxide;
(5) the dried powder was calcined at 500 ℃ for 3 hours in an air atmosphere to remove organic substances and improve the crystallinity of titanium dioxide, and the XRD result of the calcined powder showed that the main phase was barium titanate (as shown in fig. 3).
Example two:
(1) adding 3.45g of glucose into 40mL of deionized water, stirring until the solution is clear, adding 3.0g of barium titanate nano powder, and ultrasonically oscillating for 1 hour to uniformly disperse the barium titanate nano powder in the glucose aqueous solution;
(2) and pouring the ultrasonically dispersed barium titanate-glucose aqueous solution into a reaction kettle for hydrothermal reaction, wherein the temperature of the hydrothermal reaction is 160 ℃, and the heat preservation time is 6 hours. Cooling along with the furnace, removing the upper brown liquid, washing the upper brown liquid for 3 times by using absolute ethyl alcohol, coating an amorphous carbon layer on the surface of the barium titanate, and changing the color of the powder from original white to coffee;
(3) dispersing 0.25g of glucose-modified barium titanate nano powder into 30mL of absolute ethyl alcohol, carrying out ultrasonic oscillation for 1 hour, and then carrying out magnetic stirring at room temperature;
(4) 0.8mL of Ti (C) was taken4H9O)4Dissolving in 9mL of absolute ethanol solvent and injecting by a syringeSucking the mixed solution, slowly dropwise adding the mixed solution into the barium titanate suspension which is magnetically stirred in the step (3) at the speed of 0.02mm/s, after dropwise adding, continuously magnetically stirring at room temperature for 3 hours, then standing to remove the supernatant liquid, and drying in an oven at 60 ℃; the SEM photograph of the dried powder is shown in FIG. 4, and the powder also has a uniform core-shell structure;
(5) and calcining the dried powder for 3 hours at 525 ℃ in an air atmosphere, and removing organic matters and improving the crystallinity of the titanium dioxide.
Example three:
(1) adding 3.6g of glucose into 40mL of deionized water, stirring until the solution is clear, adding 3.0g of barium titanate nano powder, and ultrasonically oscillating for 1 hour to uniformly disperse the barium titanate nano powder in the glucose aqueous solution;
(2) and pouring the ultrasonically dispersed barium titanate-glucose aqueous solution into a reaction kettle for hydrothermal reaction, wherein the temperature of the hydrothermal reaction is 170 ℃, and the heat preservation time is 5 hours. Cooling along with the furnace, removing the upper brown liquid, washing the upper brown liquid for 3 times by using absolute ethyl alcohol, coating an amorphous carbon layer on the surface of the barium titanate, and changing the color of the powder from original white to coffee;
(3) dispersing 0.25g of glucose-modified barium titanate nano powder into 30mL of absolute ethyl alcohol, carrying out ultrasonic oscillation for 1 hour, and then carrying out magnetic stirring at room temperature;
(4) 0.6mL of Ti (C) was taken4H9O)4Dissolving the barium titanate powder in 9mL of absolute ethyl alcohol solvent, sucking the mixed solution by using a syringe, slowly dropwise adding the mixed solution into the barium titanate suspension which is magnetically stirred in the step (3) at the speed of 0.01mm/s, after dropwise adding, continuously magnetically stirring at room temperature for 3 hours, then standing to remove the supernatant liquid, and drying in an oven at 60 ℃; the SEM photograph of the dried powder is shown in FIG. 5, and the powder also has a uniform core-shell structure;
(5) and calcining the dried powder for 3 hours at 550 ℃ in an air atmosphere, and removing organic matters and improving the crystallinity of the titanium dioxide.
Comparative example 1:
(1) dispersing 0.25g of barium titanate nano powder into 30mL of absolute ethyl alcohol, carrying out ultrasonic oscillation for 1 hour, and then carrying out magnetic stirring at room temperature;
(2) take 1mL of Ti (C)4H9O)4Dissolving the barium titanate powder in 9mL of absolute ethyl alcohol solvent, sucking the mixed solution by using a syringe, slowly dropwise adding the mixed solution into the barium titanate suspension which is magnetically stirred in the step (1) at the speed of 0.02mm/s, after dropwise adding, continuously magnetically stirring at room temperature for 3 hours, then standing to remove the supernatant liquid, and drying in an oven at 60 ℃; the SEM photograph of the dried powder is shown in FIG. 6, and the appearance of the shell layer is disordered and irregular;
(3) and calcining the dried powder for 3 hours at 500 ℃ in an air atmosphere, and removing organic matters and improving the crystallinity of the titanium dioxide.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents or improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (7)
1. The preparation method of the barium titanate @ titanium dioxide nano powder with the uniform coating structure is characterized by comprising the following steps of:
(1) sequentially adding glucose and barium titanate nanopowder into deionized water, and performing ultrasonic dispersion to obtain barium titanate-glucose aqueous solution;
(2) carrying out hydrothermal reaction on the barium titanate-glucose aqueous solution to obtain barium titanate with the surface coated with an amorphous carbon layer as modified barium titanate nano powder;
(3) dispersing the modified barium titanate nano powder into absolute ethyl alcohol to obtain a barium titanate suspension;
(4) taking Ti (C)4H9O)4Dissolving the barium titanate powder in an absolute ethyl alcohol solvent, then dropwise adding the solution into the barium titanate suspension in the step (3), stirring at room temperature, then standing to remove supernatant liquid, and drying to obtain powder;
(5) and (4) calcining the powder in the step (4), removing organic matters and simultaneously improving the crystallinity of the titanium dioxide.
2. The preparation method of the barium titanate @ titanium dioxide nanopowder with the uniform coating structure according to claim 1, wherein in the step (1), the mass ratio of the barium titanate nanopowder to the glucose is 1: 1-1: 1.2.
3. The preparation method of barium titanate @ titanium dioxide nanopowder with uniform coating structure as recited in claim 1, wherein in the step (2), the temperature of the hydrothermal reaction is 150 ℃ to 170 ℃ and the holding time is 5 hours to 7 hours.
4. The method for preparing barium titanate @ titanium dioxide nanopowder having a uniform coating structure as claimed in claim 1, wherein in step (3), 1g of the modified barium titanate nanopowder is dispersed in at least 120mL of anhydrous ethanol.
5. The method for preparing barium titanate @ titanium dioxide nanopowder with uniform coating structure of claim 1, wherein in the step (4), 1mL of Ti (C)4H9O)4At least 9mL of absolute ethyl alcohol is needed as a solvent, and the dropping speed of the step (4) is not more than 0.02 mm/s.
6. The method for preparing barium titanate @ titanium dioxide nanopowder having uniform coating structure as claimed in claim 1, wherein the calcination temperature in step (5) is 500 ℃ to 550 ℃.
7. The barium titanate @ titanium dioxide nanopowder with the uniform coating structure prepared by the preparation method of any one of claims 1 to 6, wherein the barium titanate nanopowder is subjected to surface modification by glucose and then directly utilizes Ti (C)4H9O)4Hydrolyzing to obtain the product.
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| CN114210316A (en) * | 2021-11-05 | 2022-03-22 | 中南大学 | Preparation method and application of titanium dioxide-coated barium titanate core-shell structure nanowire ceramic |
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