CN111977693B - Device for preparing cesium tungsten bronze spherical nanocrystals and application method thereof - Google Patents

Abstract

The invention provides a device for preparing cesium tungsten bronze spherical nanocrystals, which includes a reaction device (1), a cooling device (2), a tube furnace (3), a vacuum pump (4), a waste gas collection device (5) and an air guide tube; Among them, the reaction device (1) includes a reaction chamber (11), a cylindrical cooling pipe (12), an ultrasonic atomizer (13) and a solution holding device (14), and the cooling device (2) includes a water inlet pipe (21), Outlet pipe (22) and cooling box (23). The cesium tungsten bronze nanocrystals prepared by the device are composed of monodisperse solid microspheres, and each microsphere is formed by stacking nanocrystal grains, and the grains are combined with weak force, so that the solid microspheres will not appear. Agglomeration problem, very easy to grind into well-dispersed nanocrystals, which can be used for high-quality cesium tungsten bronze nano-ink configuration; at the same time, the preparation of cesium tungsten bronze nanocrystals by this device is easy to operate, strong in practicability, and short in cycle, and can be used in large-scale Production.

Description

A device for preparing spherical nanocrystals of cesium tungsten bronze and its application method

technical field

The invention relates to the technical field of transparent heat-insulating materials and coatings, in particular to a device for preparing spherical nanocrystals of cesium tungsten bronze and a method for using the same.

Background technique

Cesium tungsten bronze (Cs _x WO ₃ ) is a non-stoichiometric functional compound with a special structure of oxygen octahedron, which has low resistivity and low-temperature superconductivity. Cesium tungsten bronze film has good near-infrared shielding performance and little absorption of visible light, so it can be used as a good near-infrared heat insulation material. At the same time, it has been found that cesium tungsten bronze can be processed into nanomaterials and then configured into ink, which can be combined with polymers, and heat insulation products with high optical quality can be prepared by spraying, scraping, roller coating and other methods, and the manufacturing cost is very low. Low, it has very attractive application prospects in the automotive and construction fields.

At present, the cesium tungsten bronze nanopowder is mainly synthesized by citric acid-induced hydrothermal synthesis. The general process is: cesium source, citric acid, and tungsten source are added to the reactor, and the liquid product is obtained by hydrothermal reaction at 190 ° C for 3 days. The product is extracted, washed, separated, and dried to prepare cesium tungsten bronze nanopowder; or after mixing tungsten source, thiourea, pH regulator, oleylamine, cesium source and water, the , prepared after 10-30 hours of reaction, but the hydrothermal synthesis method has low yield, high pressure and long reaction cycle, which has potential safety hazards and is not suitable for large-scale production.

In addition, cesium tungsten bronze nanomaterials also have technical problems such as easy agglomeration and difficult dispersion. After being formulated into ink, the stability of the ink will be poor, which will bring some difficulties to practical applications.

Contents of the invention

For the above existing problems in the prior art, the object of the present invention is to provide a device for preparing spherical nanocrystals of cesium tungsten bronze, which can prepare spherical nanocrystals of cesium tungsten bronze with good dispersion and not easy to agglomerate. Cesium tungsten bronze spherical nanocrystals can form relatively stable dispersions in common solvents, such as deionized water, ethanol, ethylene glycol methyl ether, dichloromethane, etc.; at the same time, the device is simple to operate and can prepare cesium tungsten bronze spherical nanocrystals The reaction cycle is short, and it can be used for large-scale and large-scale production.

Another object of the present invention is to provide the above method for preparing the cesium tungsten bronze spherical nanocrystal device.

The object of the present invention is achieved through the following technical solutions:

A device for preparing spherical nanocrystals of cesium tungsten bronze, characterized in that it includes a reaction device, a cooling device, a tube furnace, a vacuum pump, a waste gas collection device and an air guide tube; the reaction device includes a reaction chamber, a cylindrical cooling tube, an ultrasonic Atomizer and solution holding device, the cylindrical cooling pipe is an annular pipe with a "U" shape in cross section, and the reaction chamber is a cylindrical cavity installed in the "U" shape of the cylindrical cooling pipe. Inside the U"-shaped groove, the inner wall of the cylindrical cooling pipe is coplanar with the outer wall of the reaction chamber, the ultrasonic atomizer is installed at the bottom of the reaction chamber, and the solution holding device is installed on the ultrasonic mist The upper side of the carburetor, and the outer wall of the solution storage device is fixedly connected with the side wall of the reaction chamber; the cooling device includes a water inlet pipe, a water outlet pipe and a cooling box, and one end of the water inlet pipe is connected to the cylindrical cooling pipe. The water inlet at the top of the side is connected, and the other end is connected with the corresponding side of the cooling box. One end of the water outlet pipe is connected with the water outlet at the top of the cylindrical cooling pipe away from the water inlet, and the other end is connected with the corresponding side of the cooling box. And the water inlet is higher than the water outlet; the top of the reaction chamber is respectively connected with a "T" shaped air duct and an "L" shaped air duct, and the "T" shaped air duct is connected to the "L" All shaped air ducts extend through the top of the reaction chamber into the chamber, the bottom of the "T" shaped air duct is lower than the bottom of the "L" shaped air duct and the "T" shaped air duct is connected to the "L" The bottom of the air duct is not in contact with the solution storage device, the other end of the "L" air duct is connected to the tube furnace, and the end of the tube furnace away from the "L" air duct is respectively The exhaust gas collection device and the vacuum pump are connected through the outlet pipe and the vacuum pipe; the "L" shaped air guide pipe between the reaction chamber and the tube furnace is connected to a first air inlet pipe, and the first air inlet pipe is connected to the said tube furnace. One end of the "T"-shaped air duct is communicated with a second air intake pipe at the same time; the three sections at the inflection point of the "T"-shaped air duct are respectively provided with a first air guide valve, a second air guide valve, and a third air guide valve, the second air intake pipe is provided with a fourth air guide valve, the end of the first air intake pipe away from the "L" shaped air guide pipe is provided with a fifth air guide valve and the second air intake pipe is connected to the The connection point of the first air intake pipe and the connection point of the "T"-shaped air guide pipe and the first air intake pipe are all located between the fifth air guide valve and the "L"-shaped air guide pipe. A sixth air guide valve is arranged on the trachea, and a seventh air guide valve is arranged on the vacuum tube.

For further optimization, the solution holding device is an arc-shaped structure.

For further optimization, the cooling box is provided with a cooling switch for controlling the circulating flow of cooling water.

The method for using the device for preparing cesium tungsten bronze spherical nanocrystals is characterized in that:

a. Solution preparation and preparation: Dissolve tungsten source and cesium source in deionized water to form a solution and put it into the solution holding device, close all gas guide valves (ie, the first gas guide valve, the second gas guide valve, the second The third air guide valve, the fourth air guide valve, the fifth air guide valve, the sixth air guide valve, and the seventh air guide valve), turn on the cooling switch to make the cooling water circulate in the cooling box and the U”-shaped cooling pipe;

b. Precursor preparation: heat the tube furnace to the target temperature and keep it warm, then turn on the power supply of the ultrasonic atomizer to atomize the aqueous solution of the cesium source and the tungsten source into aerosol, open the first gas guide valve, the third gas guide valve and the sixth Gas guide valve, the carrier gas is introduced from the first gas guide valve, and the gas mist moves into the tube furnace with the carrier gas, where it is thermally cracked in the tube furnace, and white visible cesium tungsten bronze is deposited on the inner wall of the tube furnace Precursor;

c. Precursor drying: turn off the heating power of the tube furnace and the first, third, and sixth gas valves, open the seventh gas valve and the vacuum pump, and vacuumize and dry the tube furnace. Dry the precursor powder in the tube furnace;

d. Annealing treatment: close the seventh gas guiding valve, open the first gas guiding valve, the second gas guiding valve and the fourth gas guiding valve, pass H ₂ from the fourth gas guiding valve, and from the first gas guiding valve and the fourth gas guiding valve Introduce N ₂ into the second gas guiding valve, and control the air pressure, then close the first gas guiding valve, the second gas guiding valve and the fourth gas guiding valve to heat and keep the tube furnace warm;

e. Completion of the preparation: turn off the power of the tube furnace, and after natural cooling, open the fifth gas guide valve and let in air. When the air pressure is consistent with the external pressure, open the tube furnace and take out the cesium tungsten bronze nanocrystal.

For further optimization, the tungsten source is any one of ammonium tungstate and ammonium metatungstate or a mixture thereof.

For further optimization, the cesium source is any one of cesium hydroxide and cesium carbonate or a mixture thereof.

For further optimization, the molar ratio of tungsten element to cesium element in the solution in step a is 0.2-0.33:1.

For further optimization, the concentration of tungsten (ie W ⁶⁺ ) in the solution in step a is 0.2-1 mol/L.

For further optimization, the target temperature in step b is 120-230° C., and the time for heat preservation and thermal cracking is 30-300 min.

For further optimization, in the step b, the ultrasonic atomizer fully atomizes the aqueous solution of the cesium source and the tungsten source into an aerosol of 20-30 μm, and the atomization rate is 2-8 mL/min.

For further optimization, the carrier gas introduced in the step b is any one of argon, nitrogen or a mixture thereof, and the gas flow rate is 5-12 mL/min.

For further optimization, the vacuum degree of vacuum drying in the step c is -0.05～-0.06MPa.

For further optimization, the volume ratio of H ₂ to N ₂ introduced in step c is 1/20-1/5, and the pressure in the tube furnace is 0.02-0.07 MPa.

For further optimization, in the step d, the temperature for heating the tube furnace is 400-550° C., and the holding time is 1-5 hours.

For further optimization, the cesium tungsten bronze nanocrystals in the step e are regular solid microspheres with a diameter of 2-5 μm, and the solid microspheres are independent of each other; each microsphere is formed by stacking crystal grains of 20-50 nm.

In the conventional preparation process, cesium tungsten bronze nanomaterials have technical problems such as easy agglomeration and difficult dispersion, which lead to poor stability and easy precipitation and impurities after being prepared into ink. The present invention uses a high-energy dispersion mechanism produced by a specific ultrasonic atomization process, and cooperates with a specific concentration of raw materials to ensure that cesium ions enter the tungsten source and disperse evenly, and at the same time disperse the mixed solution into several small droplets; then use specific temperature thermal cracking process, the small droplets after ultrasonic atomization are cracked into aggregates with incomplete grain development, thereby reducing the force between quasi-grains and quasi-grains. At the same time, the thermal cracking process at a specific temperature further ensures The cesium ions are evenly dispersed in the droplets; finally, combined with vacuum drying, a mixed gas of _H2 and _N2 and annealing treatment, part of the hexavalent tungsten ions are reduced to pentavalent tungsten ions to form a tungsten oxide lattice. The ions are always uniformly dispersed in the tungsten source. Therefore, when the tungsten source forms a lattice, the cesium ions fill in the tungsten oxide lattice in situ, thereby forming stable, small interaction force, and easy to disperse crystal grains. The regular solid nanospheres formed by the accumulation of crystal grains with small interaction force can avoid the agglomeration of cesium tungsten bronze nanomaterials, ensure good dispersion of cesium tungsten bronze nanomaterials, and improve the heat insulation performance of tungsten bronze nanomaterials.

The present invention has following technical effect:

The invention provides a device for preparing cesium tungsten bronze spherical nanocrystals. The cesium tungsten bronze nanocrystals prepared by the device are composed of monodisperse solid microspheres, and each microsphere is formed by stacking nanocrystal grains. Combined with a weak force, the solid microspheres will not have agglomeration problems, and it is very easy to grind into well-dispersed nanocrystals, which are used for high-quality cesium tungsten bronze nano-ink configuration. At the same time, after the solid microspheres prepared by the device are ground, they can easily be modified to form relatively stable dispersions in common solvents, such as deionized water, ethanol, ethylene glycol methyl ether, dichloromethane, etc., so they can be used with Compatible with low-cost spray coating, blade coating, roller coating, inkjet printing, spin coating and other technologies, it can be applied in the field of heat insulation, with a wide range of applications and a wide range of applications.

The device is simple in operation, strong in practicability, and has a short period of preparation of cesium tungsten bronze, and can be used in large-scale and large-scale production. In addition, the raw materials for preparing cesium tungsten bronze in this device do not need other materials except tungsten source, cesium source and deionized water. Auxiliaries, solvents, stabilizers, single-phase, high-purity products, and raw materials are environmentally friendly substances. The production and use process does not produce toxic and harmful substances that have a greater impact on nature and humans, which meets the current needs of environmental protection and economic savings.

Description of drawings

Fig. 1 is a schematic structural diagram of a device for preparing cesium tungsten bronze spherical nanocrystals in an embodiment of the present invention.

Fig. 2 is a scanning electron microscope image of cesium tungsten bronze spherical nanocrystals prepared in the example of the present invention.

Fig. 3 is an X-ray diffraction pattern of cesium tungsten bronze spherical nanocrystals prepared in the examples of the present invention.

Fig. 4 is a scanning electron microscope image of monodisperse cesium tungsten bronze spherical nanocrystals prepared in the example of the present invention after wet grinding.

Fig. 5 is a nano-ink prepared from spherical nanocrystals of cesium tungsten bronze prepared in the embodiment of the present invention.

Fig. 6 is a transmittance curve of a nanocomposite thin film prepared from cesium tungsten bronze spherical nanocrystals prepared in an example of the present invention.

Among them, 1. Reaction device; 11. Reaction chamber; 12. Cylindrical cooling pipe; 13. Ultrasonic atomizer; 14. Solution holding device; 2. Cooling device; 21. Water inlet pipe; 22. Water outlet pipe; 23. Cooling box; 3. Tube furnace; 4. Vacuum pump; 5. Exhaust gas collection device; 61. "T" shaped air duct; 62. "L" shaped air duct; 63. First air intake pipe; 64. Second air intake pipe ; 65, vacuum tube; 66, air outlet pipe; 611, the first air guide valve; 612, the second air guide valve; 613, the third air guide valve; 614, the fourth air guide valve; 615, the fifth air guide valve; 616, the sixth air guide valve; 617, the seventh air guide valve.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1:

As shown in Figure 1, a kind of device for preparing cesium tungsten bronze spherical nanocrystal is characterized in that: comprise reaction device 1, cooling device 2, tube furnace 3, vacuum pump 4, waste gas collecting device 5 and air guide tube; Reaction device 1 Including a reaction chamber 11, a cylindrical cooling pipe 12, an ultrasonic atomizer 13 and a solution holding device 14, the cylindrical cooling pipe 12 is an annular pipe with a "U" shape in cross section, and the reaction chamber 11 is a cylindrical cavity 1. It is installed inside the "U" shaped groove of the cylindrical cooling pipe 12, the inner wall of the cylindrical cooling pipe 12 is coplanar with the outer wall of the reaction chamber 11, the ultrasonic atomizer 13 is installed at the bottom of the reaction chamber 11, and the solution holding device 14 Installed on the upper side of the ultrasonic atomizer 13, and the outer wall of the solution holding device 14 is fixedly connected to the side wall of the reaction chamber 11. The solution holding device 14 is an arc structure, similar to a bowl structure; the cooling device 2 includes a water inlet pipe 21, Water outlet pipe 22 and cooling box 23, one end of water inlet pipe 21 communicates with the water inlet at the top of one side of cylindrical cooling pipe 12, and the other end communicates with the corresponding side of cooling box 23, and one end of water outlet pipe 22 is far away from the water inlet at the top of cylindrical cooling pipe 12 The water outlet is connected, and the other end is connected with the corresponding side of the cooling box 23, and the water inlet is higher than the water outlet; the cooling box 23 is provided with a cooling switch for controlling the circulation of cooling water. The top of the reaction chamber 11 is respectively connected with a "T"-shaped air duct 61 and an "L"-shaped air duct 62, and the "T"-shaped air duct 61 and the "L"-shaped air duct 62 both penetrate the top of the reaction chamber 11 and extend into the chamber , the bottom of the "T"-shaped airway 61 is lower than the bottom 62 of the "L"-shaped airway and the bottom of the "T"-shaped airway 61 and the bottom of the "L"-shaped airway 62 are not in contact with the solution holding device 14, and the "L"-shaped The other end of the air guide pipe 62 communicates with the tube furnace 3, and the end of the tube furnace 3 away from the "L"-shaped air guide tube 62 is respectively connected to the waste gas collection device 5 and the vacuum pump 4 through the outlet pipe 66 and the vacuum tube 65; The "L"-shaped air duct 62 between the furnaces 3 communicates with a first air intake pipe 63, and the first air intake pipe 63 communicates with one end of the "T"-shaped air duct 61 and communicates with a second air intake pipe 64 at the same time; "T" The first air guide valve 611, the second air guide valve 612, and the third air guide valve 613 are respectively arranged in three sections at the inflection point of the font air guide pipe 61, and a fourth air guide valve 614 is set on the second air intake pipe 64, and the first air guide valve 614 is set on the first air intake pipe 64. The end of the air pipe 63 away from the "L"-shaped air guide pipe 62 is provided with a fifth air guide valve 615 and the connection point between the second air intake pipe 64 and the first air intake pipe 63, and the connection between the "T"-shaped air guide pipe 61 and the first air intake pipe 63 The points are all located between the fifth air guide valve 615 and the “L” shaped air guide pipe 62 , the sixth air guide valve 616 is arranged on the air outlet pipe 66 , and the seventh air guide valve 617 is arranged on the vacuum tube 65 .

Example 2:

A method for using a device for preparing cesium tungsten bronze spherical nanocrystals, characterized in that:

a. Solution preparation and preparation work: Dissolve ammonium tungstate and cesium hydroxide in deionized water to form a solution and put it into the solution holding device 14, and close all air guide valves (i.e. the first air guide valve 611, the second air guide valve Air valve 612, the third air guide valve 613, the fourth air guide valve 614, the fifth air guide valve 615, the sixth air guide valve 616, the seventh air guide valve 617), open the cooling switch, make the cooling water flow in the cooling box 23 and the U"-shaped cooling pipe 12; wherein, the molar ratio of tungsten to cesium in the solution is 0.33:1, and the concentration of tungsten (that is, W ⁶⁺ ) is 0.2 mol/L.

b. Precursor preparation: heat the tube furnace at 3 to 120°C and keep it warm, then turn on the power supply of the ultrasonic atomizer 13 to fully atomize the cesium source and tungsten source aqueous solution into a 20 μm aerosol, the atomization rate is 2mL/min, turn on the second A gas guide valve 611, a third gas guide valve 613, and a sixth gas guide valve 616, argon gas is introduced from the first gas guide valve 611 as a carrier gas, and the gas flow rate is 5mL/min, and the gas mist follows the movement of the carrier gas Go to the tube furnace 3 and perform thermal cracking in the tube furnace 3 for 260 minutes, and finally deposit a white and visible cesium tungsten bronze precursor on the inner wall of the tube furnace 3;

c. Precursor drying: turn off the heating power supply of the tube furnace 3 and the first gas guide valve 611, the third gas guide valve 613, and the sixth gas guide valve 616, open the seventh gas guide valve 617 and the vacuum pump 4, and the tube furnace Carry out vacuum drying, the vacuum degree is -0.05MPa, and fully dry the precursor powder in the tube furnace 3;

d. Annealing treatment: close the seventh gas guiding valve 617, open the first gas guiding valve 611, the second gas guiding valve 612 and the fourth gas guiding valve 614, pass in H ₂ from the fourth gas guiding valve 614, A gas guide valve 611 and a second gas guide valve 612 are fed with N ₂ to control the air pressure, wherein the volume ratio of H ₂ to N ₂ is 1/20, the pressure in the tube furnace 3 is 0.02MPa, and then close the first A gas-guiding valve 611, a second gas-guiding valve 612 and a fourth gas-guiding valve 614 are used to heat the tube furnace 3 to 400°C, and the holding time is 1h;

e, complete the preparation: turn off the power supply of the tube furnace 3, after natural cooling, open the fifth gas guide valve 615, and feed air, when the air pressure is consistent with the external air pressure, open the tube furnace 3, and take out the cesium tungsten bronze nanocrystal; , cesium tungsten bronze nanocrystals are regular solid microspheres with a diameter of about 2 μm, and the solid microspheres are independent of each other; each microsphere is formed by stacking grains of about 20 nm.

Figure 3 is the X-ray diffraction pattern of the monodisperse cesium tungsten bronze spherical nanocrystals prepared in Example 1. It can be seen that the precursor is an incompletely developed quasi-grain before annealing and after thermal cracking, and it is high-purity Cs after annealing _0.33 WO ₃ , its crystal form is complete and its performance is stable.

Example 3:

A method for using a device for preparing cesium tungsten bronze spherical nanocrystals, characterized in that:

a. Solution preparation and preparation: Dissolve the mixture of ammonium tungstate and ammonium metatungstate, cesium hydroxide and cesium carbonate in deionized water to form a solution and put it into the solution holding device 14, and close all the gas guide valves (i.e. the first air guide valve 611, the second air guide valve 612, the third air guide valve 613, the fourth air guide valve 614, the fifth air guide valve 615, the sixth air guide valve 616, the seventh air guide valve 617 ), turn on the cooling switch, and make the cooling water circulate in the cooling box 23 and the U "shaped cooling pipe 12; wherein, the molar ratio of tungsten element and cesium element in the solution is 0.27:1, and the concentration of tungsten (ie W ⁶⁺ ) It is 0.6mol/L.

b. Precursor preparation: heat the tube furnace at 3 to 160°C and keep it warm, then turn on the power supply of the ultrasonic atomizer 13 to fully atomize the cesium source and tungsten source aqueous solution into a 25 μm aerosol, the atomization rate is 6mL/min, turn on the second A gas pilot valve 611, a third gas pilot valve 613, and a sixth gas pilot valve 616, argon gas is introduced from the first gas pilot valve 611 as a carrier gas, and the gas flow rate is 9mL/min, and the gas mist follows the movement of the carrier gas Go to the tube furnace 3 and perform thermal cracking in the tube furnace 3 for 180 minutes, and finally deposit a white and visible cesium tungsten bronze precursor on the inner wall of the tube furnace 3;

c. Precursor drying: turn off the heating power supply of the tube furnace 3 and the first gas guide valve 611, the third gas guide valve 613, and the sixth gas guide valve 616, open the seventh gas guide valve 617 and the vacuum pump 4, and the tube furnace Carry out vacuum drying, the vacuum degree is -0.055MPa, and fully dry the precursor powder in the tube furnace 3;

d. Annealing treatment: close the seventh gas guiding valve 617, open the first gas guiding valve 611, the second gas guiding valve 612 and the fourth gas guiding valve 614, pass in H ₂ from the fourth gas guiding valve 614, A gas guide valve 611 and a second gas guide valve 612 are fed with _N2 , and the air pressure is controlled, wherein the volume ratio of _H2 to _N2 is 1/10, and the air pressure in the tube furnace 3 is 0.04MPa, and then close the first One air guide valve 611, the second air guide valve 612 and the fourth air guide valve 614, heat the tube furnace 3 to 480°C, and the holding time is 3h;

e, complete the preparation: turn off the power supply of the tube furnace 3, after natural cooling, open the fifth gas guide valve 615, and feed air, when the air pressure is consistent with the external air pressure, open the tube furnace 3, and take out the cesium tungsten bronze nanocrystal; , cesium tungsten bronze nanocrystals are regular solid microspheres with a diameter of about 3 μm, and the solid microspheres are independent of each other; each microsphere is formed by stacking grains of about 30 nm.

Add 40mL ethanol and 1mL silane coupling agent to the 10g monodisperse cesium tungsten bronze spherical nanocrystal prepared by Example 3, after grinding, it becomes a monodisperse nanocrystal with a particle size of about 30nm, as shown in Figure 4; at the same time, After the monodisperse cesium tungsten bronze spherical nanocrystals in Example 3 were wet-ground, ethanol was added to configure a nano-ink with a concentration of 5wt%. Tungsten bronze spherical nanocrystals have good dispersion and are not easy to agglomerate.

Example 4:

A method for using a device for preparing cesium tungsten bronze spherical nanocrystals, characterized in that:

a. Solution preparation and preparation work: Dissolve ammonium metatungstate and cesium carbonate in deionized water to form a solution and put it into the solution holding device 14, and close all air guide valves (i.e. the first air guide valve 611, the second guide valve Air valve 612, the third air guide valve 613, the fourth air guide valve 614, the fifth air guide valve 615, the sixth air guide valve 616, the seventh air guide valve 617), open the cooling switch, make the cooling water flow in the cooling box 23 and U"-shaped cooling pipe 12; wherein, the molar ratio of tungsten element to cesium element in the solution is 0.2:1, and the concentration of tungsten (that is, W ⁶⁺ ) is 1mol/L.

b. Precursor preparation: heat the tube furnace at 3 to 220°C and keep it warm, then turn on the power supply of the ultrasonic atomizer 13 to fully atomize the cesium source and tungsten source aqueous solution into a 30 μm aerosol with an atomization rate of 8mL/min, turn on the second A gas pilot valve 611, a third gas pilot valve 613, and a sixth gas pilot valve 616, argon gas is introduced from the first gas pilot valve 611 as a carrier gas, and the gas flow rate is 12mL/min, and the gas mist follows the movement of the carrier gas Go to the tube furnace 3 and perform thermal cracking in the tube furnace 3 for 100 minutes, and finally deposit a white and visible cesium tungsten bronze precursor on the inner wall of the tube furnace 3;

c. Precursor drying: turn off the heating power supply of the tube furnace 3 and the first gas guide valve 611, the third gas guide valve 613, and the sixth gas guide valve 616, open the seventh gas guide valve 617 and the vacuum pump 4, and the tube furnace Carry out vacuum drying, the vacuum degree is -0.06MPa, and fully dry the precursor powder in the tube furnace 3;

d. Annealing treatment: close the seventh gas guiding valve 617, open the first gas guiding valve 611, the second gas guiding valve 612 and the fourth gas guiding valve 614, pass in H ₂ from the fourth gas guiding valve 614, _N2 is passed into the first gas guide valve 611 and the second gas guide valve 612, and the air pressure is controlled, wherein the volume ratio of _H2 to _N2 is 1/5, and the air pressure in the tube furnace 3 is 0.07MPa, and then the first A gas guiding valve 611, a second gas guiding valve 612 and a fourth gas guiding valve 614 are used to heat the tube furnace 3 to 550° C., and the holding time is 5 hours;

e, complete the preparation: turn off the power supply of the tube furnace 3, after natural cooling, open the fifth gas guide valve 615, and feed air, when the air pressure is consistent with the external air pressure, open the tube furnace 3, and take out the cesium tungsten bronze nanocrystal; , cesium tungsten bronze nanocrystals are regular solid microspheres with a diameter of about 5 μm, and the solid microspheres are independent of each other; each microsphere is formed by stacking grains of about 50 nm.

Add 10 g of monodisperse cesium tungsten bronze spherical nanocrystals prepared in Example 4 to 40 mL of ethylene glycol methyl ether and 1 mL of silane coupling agent, and after grinding, add ethylene glycol methyl ether to configure a nano-ink with a concentration of 5 wt%.

The above-mentioned nano-ink is added to a volume of 20% polyurethane acrylate prepolymer, then sprayed on the glass surface, and after ultraviolet curing, a cesium tungsten bronze nanocomposite film is obtained on the glass surface; the transmittance of the above cesium tungsten bronze nanocomposite film The curve is shown in Figure 6. It can be seen from the figure that 1.5mg/m ² cesium tungsten bronze material can block more than 80% of infrared rays, while the transmittance of the film in the visible light region remains at about 70%.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (3)

1. A device for preparing cesium tungsten bronze spherical nanocrystals, characterized in that it comprises a reaction device (1), a cooling device (2), a tube furnace (3), a vacuum pump (4), a waste gas collection device (5) and Air duct; the reaction device (1) includes a reaction chamber (11), a cylindrical cooling tube (12), an ultrasonic nebulizer (13) and a solution holding device (14), and the cylindrical cooling tube (12) It is an annular tube with a "U" shape in cross section, and the reaction chamber (11) is a cylindrical cavity, which is installed inside the "U" shaped groove of the cylindrical cooling pipe (12). The inner wall of the cylindrical cooling pipe (12) is coplanar with the outer wall of the reaction chamber (11), the ultrasonic atomizer (13) is installed at the bottom of the reaction chamber (11), and the solution holding device (14) Installed on the upper side of the ultrasonic atomizer (13), and the outer wall of the solution holding device (14) is fixedly connected with the side wall of the reaction chamber (11); the cooling device (2) includes a water inlet pipe (21 ), an outlet pipe (22) and a cooling box (23), one end of the water inlet pipe (21) communicates with the water inlet at the top of one side of the cylindrical cooling pipe (12), and the other end communicates with the cooling box (23) The corresponding side is connected, one end of the water outlet pipe (22) is connected with the water outlet at the top of the cylindrical cooling pipe (12) away from the water inlet, and the other end is connected with the corresponding side of the cooling box (23), and the water inlet higher than the water outlet; the cooling box (23) is provided with a cooling switch; the top of the reaction chamber (11) is respectively connected with a "T"-shaped air duct (61) and an "L"-shaped air duct (62), And the "T"-shaped airway (61) and the "L"-shaped airway (62) extend through the top of the reaction chamber (11) into the chamber, and the "T"-shaped airway (61) The bottom is lower than the bottom of the "L"-shaped air duct (62), and the other end of the "L"-shaped air duct (62) communicates with the tube furnace (3), and the tube furnace (3) is far away from the One end of the "L"-shaped air guide tube (62) is respectively connected to the exhaust gas collection device (5) and the vacuum pump (4) through the outlet tube (66) and the vacuum tube (65); between the reaction chamber (11) and the tube type The "L"-shaped air duct (62) between the furnaces (3) communicates with a first air intake pipe (63), and the first air intake pipe (63) is connected to the "T"-shaped air duct (61) One end communicates with a second air intake pipe (64) at the same time; the three sections at the inflection point of the "T"-shaped air guide pipe (61) are respectively provided with a first air guide valve (611) and a second air guide valve (612) . The third air guide valve (613), a fourth air guide valve (614) is arranged on the second air intake pipe (64), and the first air intake pipe (63) is far away from the "L" shaped air guide pipe ( One end of 62) is provided with the fifth air guide valve (615) and the connection point between the second air intake pipe (64) and the first air intake pipe (63), the "T" shaped air guide pipe (61) and the The connection points of the first air intake pipe (63) are all located at the fifth air guide valve (615) Between the "L"-shaped air guide tube (62), a sixth air guide valve (616) is set on the outlet pipe (66), and a seventh air guide valve (617) is set on the vacuum tube (65); The using method of this device specifically comprises the following steps: a. Solution preparation and preparation: Dissolve tungsten source and cesium source in deionized water to form a solution and put it into the solution holding device (14), close all air guide valves, turn on the cooling switch, and make the cooling water flow in the cooling box ( 23) and the circular flow in the cylindrical cooling pipe (12); b. Precursor preparation: heat the tube furnace (3) to the target temperature and keep it warm, then turn on the power of the ultrasonic atomizer (13) to atomize the cesium source and tungsten source aqueous solution into aerosol, and open the first gas guide valve (611) , the third gas guiding valve (613) and the sixth gas guiding valve (616), the carrier gas is introduced from the first gas guiding valve (611), and the gas mist moves into the tube furnace (3) following the carrier gas. The tube furnace (3) is pyrolyzed, and a white visible cesium tungsten bronze precursor is deposited on the inner wall of the tube furnace (3); c. Precursor drying: turn off the heating power of the tube furnace (3) and the first gas pilot valve (611), the third gas pilot valve (613), the sixth gas pilot valve (616), and open the seventh gas pilot valve ( 617) and a vacuum pump (4), vacuumize and dry the tube furnace (3), and fully dry the precursor powder in the tube furnace (3); d. Annealing treatment: close the seventh air guide valve (617), open the first air guide valve (611), the second air guide valve (612) and the fourth air guide valve (614), from the fourth air guide valve ( 614) _{, and N 2 from} the first gas pilot valve (611) and the second gas pilot valve (612), and control the air pressure, and then close the first gas pilot valve (611), the second pilot The gas valve (612) and the fourth gas guide valve (614) are used to heat and keep the tube furnace (3); e. Completion of preparation: turn off the power supply of the tube furnace (3), and after natural cooling, open the fifth gas guide valve (615) and let in air. When the air pressure is consistent with the external pressure, open the tube furnace (3) and take out the cesium Tungsten bronze nanocrystals; the cesium tungsten bronze nanocrystals are regular solid microspheres with a diameter of 2 to 5 μm, and the solid microspheres are independent of each other, and each microsphere is formed by stacking grains of 20 to 50 nm; The tungsten source is any one or a mixture of ammonium tungstate and ammonium metatungstate; the cesium source is any one or a mixture of cesium hydroxide and cesium carbonate; The target temperature in the step b is 120-230°C, the time for heat preservation and thermal cracking is 30-300min; the temperature for heating the tube furnace in the step d is 400-550°C, and the heat preservation time is 1-5h; The molar ratio of tungsten element to cesium element in the solution in step a is 0.2-0.33:1. 2. A kind of device for preparing cesium tungsten bronze spherical nanocrystals according to claim 1, characterized in that: the carrier gas introduced in the step b is any one of argon, nitrogen or its mixture, wherein The gas flow rate is 5-12 mL/min. 3. A device for preparing cesium tungsten bronze spherical nanocrystals according to claim 1, characterized in that: the vacuum degree of vacuum drying in the step c is -0.05～-0.06MPa.

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