CN105967721A - A kind of preparation method of Bi2SiO5 porous material - Google Patents

Abstract

The invention discloses a preparation method of a Bi2SiO5 porous material. The preparation method utilizes bismuth nitrate and ethyl orthosilicate as raw materials and anhydrous ethanol and deionized water as solvents and comprises uniformly dispersing ions in xerogel powder through a dispersant and carrying out direct pressing molding and heat treatment to obtain the Bi2SiO5 porous material. The preparation method utilizes complexation action to realize uniform compounding, effectively shortens a preparation period and has the advantages of simple equipment and low cost.

Description

A kind of preparation method of Bi2SiO5 porous material

technical field

The invention belongs to the technical field of materials, and in particular relates to a preparation method of a Bi ₂ SiO ₅ porous material.

Background technique

At present, the crystal phases of compounds discovered and studied in the Bi ₂ O ₃ -SiO ₂ system mainly include Bi ₂ SiO ₅ crystal, Bi ₄ Si ₃ O ₁₂ crystal and Bi ₁₂ SiO ₂₀ crystal phase, and the former one is metastable Compounds, the latter two are stable compounds. Metastable phase Bi ₂ SiO ₅ not only has dielectric, pyroelectric and nonlinear optical properties, but also has ferroelectric properties due to its non-centrosymmetric crystal structure. With its special structural characteristics, the porous material not only overcomes the problem of nano-powder agglomeration, but also makes the material itself have more superior performance. At present, the method of preparing porous materials is mainly to use hydrothermal method, sol-gel method, precipitation method, etc. to synthesize powder, and then use foaming agent, binder, etc. to compound with powder, and prepare porous material after forming. For bulk materials, the preparation period of these methods is long and complicated. This patent aims at the disadvantages of the current preparation methods for preparing porous materials, and invented a short and effective preparation method for Bi ₂ SiO ₅ porous materials.

Contents of the invention

In order to overcome the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a method for preparing a Bi ₂ SiO ₅ porous material, which has the characteristics of simple production process, simple equipment requirements and short cycle time.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A preparation method of Bi ₂ SiO ₅ porous material, comprising the steps of:

(1) Dissolve citric acid in ammonia water to obtain a citric acid solution, measure 1/3 of the citric acid solution, dissolve ethyl orthosilicate in it to form solution A for later use; dissolve bismuth nitrate in the remaining citric acid solution to form Solution B;

(2) Add the dispersant to solution B, then add absolute ethanol and stir to dissolve, add solution A to it under constant stirring, and then adjust the pH value to 8-10 to obtain sol C;

(3) Put sol C in a water bath at 80-85°C for 1.5-3 hours until gelation, then dry at 140-160°C to form xerogel, dry it naturally at room temperature, grind and sieve to obtain xerogel powder ;

(4) The sieved dry powder is directly dry-pressed to form a block green body material, and finally the block green body material is subjected to heat treatment to obtain a Bi ₂ SiO ₅ porous material.

In described step (1), the amount of ammoniacal liquor is as the criterion that can dissolve citric acid.

In the described step (1), the consumption of tetraethyl orthosilicate and bismuth nitrate satisfies the molar ratio of Si and Bi is (2:1)～(1:2), and the sum of Si ion and Bi ion and citric acid The molar ratio is 1:(1~1.5).

In the step (2), the dispersant is composed of ethylenediaminetetraacetic acid, citric acid, diethylenetriaminepentacarboxylic acid, tartaric acid, ethylene glycol and polyethylene glycol.

After the dispersant is added to solution B, the concentration range of each component of the dispersant is 0-0.5 mol/L.

In the step (2), the volume of absolute ethanol is 1/2-1 of the volume of ammonia water.

In the step (4), the heat treatment is to bury the ZnO powder at a temperature of 600°C to 700°C.

Compared with the prior art, the beneficial effects of the present invention are: in the preparation method of the _{Bi2SiO5 porous} material provided by the present invention, ethylenediaminetetraacetic acid, citric acid, diethylenetriaminepentacarboxylic acid, tartaric acid, Ethylene glycol, polyethylene glycol 400, polyethylene glycol 4000, polyethylene glycol 6000, etc. are used as dispersants to make silicon ions and bismuth ions evenly distributed in the gel. The gel is in the form of viscous powder, so that the xerogel can be used for direct compression molding. Combining burial and appropriate heat treatment system, the foaming and decomposition combustion process of organic matter can be used to form Bi ₂ SiO ₅ porous materials. This method can reduce the preparation process such as granulation and aging, so that the process steps are less and the preparation cycle is shortened. The complexation and dispersion effect of the organic matter used makes the crystal phase of the Bi ₂ SiO ₅ porous material pure, and the pore size and distribution are controllable. Good sex.

detailed description

The implementation of the present invention will be described in detail below in conjunction with the examples.

Example 1

A preparation method of Bi ₂ SiO ₅ porous material, comprising the steps of:

(1) Dissolve citric acid in ammonia water (volume concentration 25% to 28%), the amount of ammonia water is subject to the ability to dissolve citric acid, measure 1/3 of the citric acid solution, and dissolve ethyl orthosilicate in it Solution A is formed for subsequent use; bismuth nitrate is dissolved in the remaining citric acid solution to form solution B, wherein Si: Bi (molar ratio)=2:1, the sum of Si ions and Bi ions: citric acid (molar ratio)=1: 1.

(2) Weigh a certain amount of dispersant (composed of ethylenediaminetetraacetic acid, citric acid, diethylenetriaminepentacarboxylic acid, tartaric acid, ethylene glycol, polyethylene glycol, wherein polyethylene glycol includes polyethylene glycol) Glycol 400, Polyethylene Glycol 4000 and Polyethylene Glycol 6000.) Add in solution B, the concentration of each component of dispersant is controlled at 0.5mol/L, add dehydrated alcohol and stir to dissolve (the volume of dehydrated alcohol is ammoniacal liquor 1/2 of the volume), solution A was added thereto under continuous stirring, and then the pH value was adjusted to 8-10 to obtain sol C.

(3) Put Sol C in a water bath at 80°C for 1.5-3 hours until gelation. Then dry at 140° C. to form a xerogel, and then dry it naturally at room temperature, then grind and sieve the powder.

(4) The sieved dry powder is directly dry-pressed to form a block-shaped green body material, and finally the block-shaped green body material is buried and fired in ZnO powder to obtain a Bi ₂ SiO ₅ porous material, and the heat treatment temperature is 700°C. The particle size in the obtained Bi ₂ SiO ₅ porous material is about 100nm-400nm, and the gap size is 80nm-150nm.

Example 2

A preparation method of Bi ₂ SiO ₅ porous material, comprising the steps of:

(1) Dissolve citric acid in ammonia water (volume concentration 25% to 28%), the amount of ammonia water is subject to the ability to dissolve citric acid, measure 1/3 of the citric acid solution, and dissolve ethyl orthosilicate in it Form solution A for later use; dissolve bismuth nitrate in the remaining citric acid solution to form solution B, wherein Si: Bi (molar ratio)=1:2, the sum of Si ions and Bi ions: citric acid (molar ratio)=1: 1.5.

(2) Weigh a certain amount of dispersant (composed of ethylenediaminetetraacetic acid, citric acid, diethylenetriaminepentacarboxylic acid, tartaric acid, ethylene glycol, polyethylene glycol.) Add in solution B, each dispersant The concentration of the components is controlled at 0.5mol/L, add absolute ethanol and stir to dissolve (the volume of absolute ethanol is equal to the volume of ammonia water), add solution A to it under constant stirring, and then adjust the pH value to 8-10 to obtain the sol c.

(3) Put Sol C in a water bath at 85°C for 1.5-3 hours until gelation. Then dry at 160° C. to form a xerogel, and then dry it naturally at room temperature, then grind and sieve the powder.

(4) The sieved dry powder is directly dry-pressed to form a block-shaped green body material, and finally the block-shaped green body material is buried and fired in ZnO powder to obtain a Bi ₂ SiO ₅ porous material, and the heat treatment temperature is 600°C. The particle size in the obtained Bi ₂ SiO ₅ porous material is about 100nm-400nm, and the gap size is 80nm-150nm.

Example 3

A preparation method of Bi ₂ SiO ₅ porous material, comprising the steps of:

(1) Dissolve citric acid in ammonia water (volume concentration 25% to 28%), the amount of ammonia water is subject to the ability to dissolve citric acid, measure 1/3 of the citric acid solution, and dissolve ethyl orthosilicate in it Form solution A for subsequent use; dissolve bismuth nitrate in the remaining citric acid solution to form solution B, wherein Si: Bi (molar ratio)=1:1, the sum of Si ions and Bi ions: citric acid (molar ratio)=1: 1.2.

(2) Weigh a certain amount of dispersant (composed of ethylenediaminetetraacetic acid, citric acid, diethylenetriaminepentacarboxylic acid, tartaric acid, ethylene glycol, polyethylene glycol) and add it to solution B. Each group of dispersant The concentration of each part is controlled at 0.01, 0.1, 0.1, 0.5, 0.5, 0.5mol/L, add absolute ethanol and stir to dissolve (the volume of absolute ethanol is 1/2 of the volume of ammonia water), and add solution A to it under constant stirring , and then adjust the pH value to 8-10 to obtain Sol C.

(3) Put Sol C in a water bath at 85°C for 1.5-3 hours until gelation. Then dry at 150° C. to form a xerogel, and then dry the powder naturally at room temperature and then grind and sieve the powder.

(4) The sieved dry powder is directly dry-pressed to form a block-shaped green body material, and finally the block-shaped green body material is buried and fired in ZnO powder to obtain a Bi ₂ SiO ₅ porous material, and the heat treatment temperature is 650°C. The particle size in the obtained Bi ₂ SiO ₅ porous material is about 100nm-400nm, and the gap size is 80nm-150nm.

Claims (7)

1. a Bi ₂ SiO ₅ preparation method of porous material, is characterized in that, comprises the steps: (1) Dissolve citric acid in ammonia water to obtain a citric acid solution, measure 1/3 of the citric acid solution, dissolve ethyl orthosilicate in it to form solution A for later use; dissolve bismuth nitrate in the remaining citric acid solution to form Solution B; (2) Add the dispersant to solution B, then add absolute ethanol and stir to dissolve, add solution A to it under constant stirring, and then adjust the pH value to 8-10 to obtain sol C; (3) Put sol C in a water bath at 80-85°C for 1.5-3 hours until gelation, then dry at 140-160°C to form xerogel, dry it naturally at room temperature, grind and sieve to obtain xerogel powder ; (4) The sieved dry powder is directly dry-pressed to form a block green body material, and finally the block green body material is subjected to heat treatment to obtain a Bi ₂ SiO ₅ porous material. 2 . The method for preparing the Bi ₂ SiO ₅ porous material according to claim 1 , characterized in that, in the step (1), the amount of ammonia water is based on the ability to dissolve citric acid. 3. according to the described Bi of claim 1 ₂ SiO ₅ preparation method of porous material, it is characterized in that, in described step (1), the consumption of ethyl orthosilicate and bismuth nitrate meets the mol ratio of Si and Bi is (2 :1)～(1:2), and the molar ratio of the sum of Si ions and Bi ions to citric acid is 1:(1～1.5). 4. according to the described _Bi2SiO5 preparation method of claim ₁ , it is characterized in that, in described step (2), described dispersion agent is made of ethylenediaminetetraacetic acid, citric acid, diethylenetriaminepentacarboxylic acid acid, tartaric acid, ethylene glycol and polyethylene glycol. 5 . The method for preparing the Bi ₂ SiO ₅ porous material according to claim 4 , characterized in that, after the dispersant is added to solution B, the concentration range of each component of the dispersant is 0-0.5 mol/L. 6 . The method for preparing the Bi ₂ SiO ₅ porous material according to claim 4 , characterized in that, in the step (2), the volume of absolute ethanol is 1/2-1 of the volume of ammonia water. 7. The preparation method of the _Bi2SiO5 porous material according to claim ₁ , characterized in that, in the step (4), the heat treatment is carried out in the ZnO powder, and the temperature is 600°C-700°C .