Preparation method of superfine cesium tungsten bronze powder

Abstract

The application discloses a preparation method of superfine cesium tungsten bronze powder, which comprises the following steps: mixing a tungsten source, a cesium source and an organic solvent to form a uniform solution under the condition of 80-150 DEG C, and then reacting at 100-300 DEG C to obtain the superfine cesium tungsten bronze powder; the organic solvent is an organic compound with a boiling point not lower than the reaction temperature. The tungsten source and the cesium source are placed in a pure organic solvent to form a uniform solution after heat preservation for a period of time, and then heated to obtain the cesium tungsten bronze nanoparticles with a particle size range of 5-10 nm and uniform particle size or the cesium tungsten bronze nanosheets with a thickness range of 5-10 nm and uniform size.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of superfine cesium tungsten bronze powder and belongs to the technical field of preparation of cesium tungsten bronze powder. BACKGROUND

[0002] Cesium tungsten bronze (Cs x WO3; 0 < x < 0.33) is a non-stoichiometric functional compound, which has been widely concerned in the field of transparent heat insulation energy saving due to its high visible light transmittance and good near-infrared shielding performance, and has been widely applied in the fields of automobile heat insulation film, building curtain wall, energy-saving glass and the like, and has a broad application prospect in the fields of medical treatment, laser printing, electronic packaging, electrochromism and the like.

[0003] There are multiple patent disclosure documents for the preparation of superfine cesium tungsten bronze powder:

[0004] For example, CN109368702A discloses a preparation method of cesium tungstate with a tungsten bronze structure, and the production process mainly comprises the following steps: mixing cesium carbonate, tungsten oxide and deionized water, adding a trace amount of a sintering aid, performing normal-temperature wet ball milling, drying the obtained slurry, performing heat treatment in a mixed atmosphere of H2 and N2, and then performing secondary sintering in an air atmosphere, so as to obtain cesium tungstate powder with a particle size of about 100 nm.

[0005] For example, CN114573030A discloses a preparation method of cesium tungsten bronze powder, and the production process mainly comprises the following steps: dissolving at least one organic acid selected from acetic acid, propionic acid, oxalic acid, carbonic acid, malic acid, gluconic acid, formic acid, lactic acid and benzoic acid in water, dissolving ammonium paratungstate in the aqueous solution of the organic acid, adding a cesium source aqueous solution into the above solution, stirring and drying to obtain a precursor, and then performing annealing treatment at 500-900 DEG C to obtain cesium tungsten bronze powder with a particle size of 20-200 nm.

[0006] For example, CN114014364A discloses an environmentally-friendly method for preparing tungsten bronze nanomaterial, and the production process mainly comprises the following steps: dissolving tungstate, tartaric acid and an alkali metal compound in water, placing the mixture in a hydrothermal reaction kettle and reacting at 120-200 DEG C for 12-24 h, and drying the solid product to obtain tungsten bronze nanomaterial with a particle size of 50-200 nm.

[0007] The present disclosed patent mainly utilizes high-temperature solid-phase reaction, hydrothermal synthesis and other methods to prepare cesium tungsten bronze. However, in the high-temperature solid-phase reaction, in order to make the elements uniformly distributed, a relatively high reaction temperature is usually required, thus the size of the cesium tungsten bronze powder is usually large, and the particle size distribution is uneven, which is difficult to fully exert the near-infrared shielding performance of the cesium tungsten bronze. In the hydrothermal synthesis, the product uniformity is improved due to the presence of the solvent, and the size of the cesium tungsten bronze can be controlled by adding organic matters, but the reaction is still mainly carried out in an aqueous solution, the reaction time is too long, and the utilization of the organic matters is not sufficient, which is difficult to refine the size of the cesium tungsten bronze and efficiently prepare ultra-fine cesium tungsten bronze powder. SUMMARY

[0008] In order to solve the problems in the prior art, the purpose of the present application is to provide a preparation method of ultra-fine cesium tungsten bronze powder, which comprises the following steps: placing a tungsten source and a cesium source in a pure organic solvent to form a uniform solution after heat preservation for a period of time, and then heating to react, so as to obtain cesium tungsten bronze nanoparticles with a particle size range of 5-10 nm and uniform particle size or cesium tungsten bronze nanosheets with a thickness range of 5-10 nm and uniform size.

[0009] In order to achieve the above technical purpose, the present application adopts the following technical scheme:

[0010] A preparation method of ultra-fine cesium tungsten bronze powder, which comprises the following steps: mixing a tungsten source, a cesium source and an organic solvent to form a uniform solution after heat preservation at 80-150℃, and then reacting at 100-300℃ to obtain ultra-fine cesium tungsten bronze powder; the organic solvent is an organic compound with a boiling point not lower than the reaction temperature.

[0011] Preferably, the tungsten source is one or more of tungstic acid, sodium tungstate, ammonium tungstate, ammonium metatungstate, ammonium paratungstate and tungsten chloride.

[0012] Preferably, the cesium source is one or more of cesium hydroxide, cesium carbonate, cesium chloride, cesium oxalate and cesium citrate.

[0013] Preferably, the organic solvent is selected from one or more of organic amines, organic alcohols, organic acids, olefins and alkanes with a boiling point not lower than the reaction temperature; further preferably, the organic solvent is selected from one or more of organic amines with a carbon atom number of 8-36, organic alcohols with a carbon atom number of 7-30, organic acids with a carbon atom number of 5-40, olefins with a carbon atom number of 8-40 and alkanes with a carbon atom number of 8-40; more preferably, the organic solvent is selected from one or more of organic amines, organic alcohols, organic acids, olefins and alkanes with a carbon atom number of 10-20. For example, dodecylamine, hexadecylamine, octadecylamine, oleylamine, dodecanol, hexadecanol, octadecanol, oleyl alcohol, dodecanoic acid, hexadecanoic acid, octadecanoic acid, oleic acid, octene, dodecene, hexadecene, octane, octadecene, dodecane, hexadecane, octadecane, etc.

[0014] Preferably, the molar ratio of the tungsten source to the cesium source is 0.01-1.

[0015] Preferably, the mass ratio of the tungsten source to the organic solvent is 1-100.

[0016] In the preparation of the existing ultrafine cesium tungsten bronze powder, the high-temperature solid-phase reaction method often leads to a powder size that is too large and a non-uniform particle size distribution, and although the hydrothermal synthesis method uses an organic substance to control the size of the cesium tungsten bronze, the main solvent is still water, which is difficult to fully exert the morphology control effect of the organic substance. In the present application, a pure organic compound with a boiling point not lower than the reaction temperature is used as a solvent for regulating the reaction, and the tungsten source and the cesium source are decomposed in the pure organic solvent to obtain a cesium tungsten bronze crystal nucleus, and at the same time, the organic solvent is adsorbed on the surface of the generated cesium tungsten bronze crystal nucleus to prevent the particle or nanosheet from growing further, thereby obtaining an ultrafine cesium tungsten bronze powder. The key of the present application lies in: first, the organic solvent used in the present application has a boiling point not lower than the reaction temperature and will not boil at the reaction temperature; second, after mixing the tungsten source, the cesium source and the organic solvent, the mixture must be first kept warm to form a uniform solution, which can avoid the powder from growing excessively due to agglomeration in the subsequent reaction. Based on the above two points, the organic solvent can fully exert the regulating effect on the size and dispersity of the cesium tungsten bronze, and the cesium tungsten bronze nanoparticles with a particle size range of 5-10 nm and a uniform particle size or the cesium tungsten bronze nanosheets with a thickness range of 5-10 nm and a uniform size are obtained.

[0017] The advantages of the present application are:

[0018] In the present application, a pure organic compound with a boiling point not lower than the reaction temperature is used as a solvent for regulating the reaction, which can fully exert the regulating effect of the organic compound on the size and dispersity of the cesium tungsten bronze, and the cesium tungsten bronze nanoparticles with a particle size range of 5-10 nm and a uniform particle size or the cesium tungsten bronze nanosheets with a thickness range of 5-10 nm and a uniform size are obtained. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The XRD image of the ultrafine cesium tungsten bronze nanoparticles obtained in Example 1. DETAILED DESCRIPTION

[0020] The present application will be further described in detail below in combination with specific examples. The following specific examples are only used to illustrate the present application and are not intended to limit the present application.

[0021] Example 1

[0022] (1) Take ammonium tungstate and cesium chloride with a molar ratio of 1:0.33, and use a mixed solution of oleylamine and oleic acid with a mass ratio of 3:1 as the organic solvent, and the mass ratio of the organic solvent to ammonium tungstate is 1:25;

[0023] (2) The tungsten acid, cesium chloride, and oleic acid in (1) are mixed to form a uniform solution at 100°C for 30 min;

[0024] (3) The uniform solution in (2) is heated to 250°C at 5°C / min and reacted for 10 min;

[0025] (4) When the reaction solution prepared in (3) is naturally cooled to 80°C, it is centrifuged and washed 3 times;

[0026] (5) The sample collected in (4) is vacuum dried at 80°C for 1 h to obtain ultrafine cesium tungsten bronze nanoparticles.

[0027] The ultrafine cesium tungsten bronze nanoparticles prepared in this example have a particle size range of 5-8 nm, and the XRD image is as shown in Figure 1 .

[0028] Example 2

[0029] (1) Tungsten acid and cesium chloride with a molar ratio of 1:0.33 are taken, and a mixed solution of octadecene and oleic acid with a mass ratio of 4:1 is used as an organic solvent, and the mass ratio of the organic solvent to the tungsten acid is 1:16;

[0030] (2) The tungsten acid, cesium chloride, octadecene, and oleic acid in (1) are mixed to form a uniform solution at 120°C for 10 min;

[0031] (3) The uniform solution in (2) is heated to 280°C at 5°C / min and reacted for 10 min;

[0032] (4) When the reaction solution prepared in (3) is naturally cooled to 80°C, it is centrifuged and washed 3 times;

[0033] (5) The sample collected in (4) is vacuum dried at 80°C for 1 h to obtain ultrafine cesium tungsten bronze nanoparticles.

[0034] The ultrafine cesium tungsten bronze nanoparticles prepared in this example have a particle size range of 7-10 nm.

[0035] Example 3

[0036] (1) Ammonium metatungstate and cesium chloride with a molar ratio of 1:0.33 are taken, and a mixed solution of octadecene and octadecanoic acid with a mass ratio of 4:1 is used as an organic solvent, and the mass ratio of the organic solvent to the ammonium metatungstate is 1:30;

[0037] (2) The ammonium metatungstate, cesium chloride, octadecene, and octadecanoic acid in (1) are mixed to form a uniform solution at 80°C for 30 min;

[0038] (3) The uniform solution in (2) is heated to 150°C at 2°C / min and reacted for 5 h;

[0039] (4) When the reaction solution prepared in (3) is naturally cooled to 80°C, centrifugal washing is performed 3 times;

[0040] (5) The sample collected in (4) is vacuum dried at 80°C for 1 h to obtain superfine cesium tungsten bronze nanosheets.

[0041] The superfine cesium tungsten bronze nanosheets prepared in the example have a thickness in the range of 5-10 nm.

[0042] Comparative Example 1

[0043] (1) Ammonium tungstate and cesium chloride with a molar ratio of 1:0.33 are taken, and a mixed solution of oleylamine and oleic acid with a mass ratio of 3:1 is used as an organic solvent, and the mass ratio of the organic solvent to ammonium tungstate is 1:25;

[0044] (2) The ammonium tungstate, cesium chloride, oleylamine and oleic acid in (1) are stirred and mixed, and then heated to 250°C at a rate of 5°C / min, and reacted for 10 min;

[0045] (3) When the reaction solution prepared in (2) is naturally cooled to 80°C, centrifugal washing is performed 3 times;

[0046] (4) The sample collected in (3) is vacuum dried at 80°C for 1 h to obtain superfine cesium tungsten bronze powder.

[0047] The superfine cesium tungsten bronze nanosheets prepared in the example have a thickness in the range of 5-10 nm.

Claims

1. A method for preparing ultrafine cesium tungsten bronze powder, characterized by the steps of: The tungsten source, the cesium source and the organic solvent are mixed and incubated at 80-150 DEG C to form a uniform solution, and then reacted at 100-300 DEG C to obtain cesium tungsten bronze nanoparticles with a particle size range of 5-10 nm and uniform particle size or cesium tungsten bronze nanosheets with a thickness range of 5-10 nm and uniform size; the organic solvent is selected from one or more of organic amines, organic alcohols, organic acids, olefins and alkanes with a boiling point not lower than the reaction temperature. ​ 2. The method for preparing ultrafine cesium tungsten bronze powder according to claim 1, characterized in that: The tungsten source is one or more of tungstic acid, sodium tungstate, ammonium tungstate, ammonium metatungstate, ammonium paratungstate and tungsten chloride.

3. The method for preparing ultrafine cesium tungsten bronze powder according to claim 1, characterized in that: The cesium source is one or more of cesium hydroxide, cesium carbonate, cesium chloride, cesium oxalate and cesium citrate.

4. The method for preparing ultrafine cesium tungsten bronze powder according to claim 1, characterized in that: The organic solvent is selected from one or more of organic amines with a carbon atom number of 8-36, organic alcohols with a carbon atom number of 7-30, organic acids with a carbon atom number of 5-40, olefins with a carbon atom number of 8-40 and alkanes with a carbon atom number of 8-40.

5. The method for preparing ultrafine cesium tungsten bronze powder according to claim 4, characterized in that: The organic solvent is selected from one or more of organic amines, organic alcohols, organic acids, olefins and alkanes with a carbon atom number of 10-20.

6. The method for preparing ultrafine cesium tungsten bronze powder according to claim 5, characterized in that: The organic solvent is selected from one or more of dodecylamine, hexadecylamine, octadecylamine, oleylamine, dodecanol, hexadecanol, octadecanol, oleyl alcohol, dodecanoic acid, hexadecanoic acid, octadecanoic acid, oleic acid, octene, dodecene, hexadecene, octane, octadecene, dodecane, hexadecane and octadecane.

7. The method for preparing ultrafine cesium tungsten bronze powder according to any one of claims 1-3, characterized in that: The molar ratio of the tungsten source to the cesium source is 0.01-1.

8. The method for preparing ultrafine cesium tungsten bronze powder according to any one of claims 1-3, characterized in that: The mass ratio of the tungsten source to the organic solvent is 1-100.

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