CN113249091B - ATO (antimony tin oxide) coated cesium tungsten bronze composite nano powder and preparation method thereof - Google Patents

Abstract

An ATO-coated cesium tungsten bronze composite nano-powder and a preparation method thereof of the present invention, wherein the coating layer is antimony-doped tin dioxide ATO, and the particles of the composite nano-powder include a cesium tungsten bronze core and a coating of the cesium tungsten For the bronze-doped antimony-doped tin dioxide ATO shell, the general formula of the cesium tungsten bronze core is Cs _x WO ₃ , where 0.1≤x≤0.33. In the preparation process, the surface of cesium tungsten bronze is coated with chemically stable ATO, which isolates the core of cesium tungsten bronze from contact with water or oxygen outside, improves the chemical stability of cesium tungsten bronze, and maintains good dispersibility. Combined with the near-infrared absorption performance of cesium tungsten bronze nanopowder Cs _x WO ₃ , it can be further improved without affecting the high transmittance of visible light and high blocking rate of infrared light of the cesium tungsten bronze core, which is significantly better than the existing infrared blocking rate. coating.

Description

A kind of ATO coated cesium tungsten bronze composite nanopowder and preparation method thereof

Technical field:

The invention belongs to the technical field of transparent heat-insulating powder, and in particular relates to an ATO-coated cesium tungsten bronze composite nano-powder and a preparation method thereof. The powder can be widely used in preparing infrared-blocking heat-insulating coatings and films.

Background technique:

Infrared rays are electromagnetic waves with wavelengths between microwaves and visible light, with wavelengths between 760nm and 2.5mm. Infrared rays, especially near-infrared rays, have obvious thermal effects, accounting for more than half of the solar radiation heat, so they need to be regulated in many fields. In the field of construction, the application of infrared blocking glass/coating/film can reduce the heat of near-infrared radiation, reduce the rise of indoor temperature in summer, reduce the use of refrigeration equipment such as air conditioners, and achieve the purpose of energy saving. In the automotive field, it is also possible to reduce the temperature inside the car by applying infrared blocking glass/coating/film, bringing a better driving experience and achieving the purpose of energy saving.

The reported inorganic materials with strong near-infrared absorption or reflection properties mainly include noble metals (gold, silver, etc.), black compounds (ruthenium, rhodium, and iridium-containing oxides), semiconductor oxides (FTO, AZO, ITO), Rare earth hexaboride (PrB ₆ , NdB ₆ , LaB ₆ , etc.) and tungsten bronze functional materials. This type of conductive oxide powder generally has a strong absorption capacity for near-infrared light with a wavelength greater than 1500nm. Among the tungsten bronze functional materials, cesium tungsten bronze has a strong absorption ability to near-infrared light with a wavelength of 950nm to 1500nm, showing better stability and infrared absorption and photothermal conversion performance than other types of tungsten bronze. The mainstream of preparation and application.

Many literatures show that cesium tungsten bronze (Cs _x WO ₃ ) powder with excellent properties can be prepared by traditional solid-state reaction method, gas-phase method or solvothermal/hydrothermal method. The traditional solid-state reaction method is simple to operate, requires less capital investment, and has a large output. However, this method cannot control the morphology of the obtained product and has high agglomeration. It needs ball milling for secondary refinement before it can be applied. Takeda H et al. used WO ₃ ·NH ₃ as the tungsten source, and M salt containing the required metal elements as the auxiliary raw material. The aqueous solution of the two was fully mixed, dried at 130°C, and then mixed in H ₂ /N ₂ Heating under atmosphere, and finally heating under N ₂ atmosphere at 800°C to obtain the final product, successfully prepared M _0.33 WO ₃ (M=Na, Ti, Rb, Cs) and Na _0.75 WO ₃ . Nanomaterials with various morphologies can be prepared by the gas phase method, but the experimental equipment required by this method is relatively complicated, the requirements for experimental conditions are relatively high, and the capital investment is large. In 1985, M.Green and A.Travlos used commercial WO ₃ powder and metal sodium as raw materials, heated these two materials separately, and prepared sodium tungsten bronze (Na _x WO ₃ ) film by co-evaporation method. The process of preparing tungsten bronze by solvent hydrothermal method is relatively mature, with simple operation and simple equipment, and various products with special shapes can be obtained. Guo CS et al. used ammonium paratungstate as the tungsten source, dissolved ammonium paratungstate in ethylene glycol solution at 190°C, waited for the solution to air-cool to room temperature, then added acetic acid, reacted in a hydrothermal kettle at 200°C for 72 hours, washed and dried to obtain ammonium tungsten bronze , the synthesized ammonium tungsten bronze has excellent near-infrared shielding properties.

However, pure cesium tungsten bronze has insufficient absorption of infrared rays greater than 1500nm, and has strong reducibility, and cesium tungsten bronze is easily oxidized at higher temperatures. At the same time, cesium tungsten bronze is soluble in a strong alkaline solution placed in the air atmosphere, as shown in the following equation.

2Cs _x WO ₃ +x/2O ₂ =xCs ₂ WO ₄ +(2-x)WO ₃

2Cs _x WO ₃ +(8-4x)NaOH+xO ₂ = 4NaWO ₄ +(4-2x)H ₂ O

Invention content:

The purpose of the present invention is to overcome the shortcomings of insufficient stability of cesium tungsten bronze in the prior art, and provide an antimony-doped tin dioxide ATO coating with excellent absorption performance and excellent stability for infrared light with an infrared wavelength greater than 1500 nm. Cesium tungsten bronze composite nanopowder and its preparation method. The chemical stability of cesium tungsten bronze is improved by coating antimony-doped tin dioxide ATO on the surface of cesium tungsten bronze. In addition, the nano-powder maintains good dispersion through the coating of the oxide layer. Moreover, the antimony-doped tin dioxide ATO coating can further improve the absorption capacity of cesium tungsten bronze in the infrared region with a wavelength greater than 1500nm without affecting the high transmittance of visible light. By controlling the thickness and uniformity of the oxide coating layer, the visible light transmission performance of the infrared blocking coating and film prepared by the composite powder is well maintained; when used for light-to-heat conversion, the composite powder is The light-to-heat conversion performance is enhanced by the coating's excellent absorption ability to sunlight.

The preparation process includes: mixing the powder that provides the cesium source and the tungsten source, organic alcohol and organic acid, and performing a hydrothermal reaction to obtain a cesium tungsten bronze precursor solution, washing the cesium tungsten bronze precursor solution three times with deionized water and organic alcohol , cesium tungsten bronze powder is obtained by drying in an oven after several centrifugation operations, the cesium tungsten bronze powder is dissolved in alkaline alcohol solution or aqueous solution, and then the oxide shell is deposited on the cesium tungsten bronze monolayer or layer by layer by hydrolysis. The surface of the tungsten bronze inner core is obtained to obtain the oxide-coated cesium tungsten bronze composite nanopowder.

To achieve the above object, the present invention adopts the following technical solutions:

An ATO-coated cesium tungsten bronze composite nanopowder, the particles of the composite nanopowder include a cesium tungsten bronze core and an ATO shell covering the cesium tungsten bronze core, the general formula of the cesium tungsten bronze core is Cs _x WO ₃ , where 0.1≤x≤0.33, the core of the cesium tungsten bronze is a nanosphere with a particle size of 20-80nm; the thickness of the ATO shell is ≤30nm to avoid further thickening of the composite nanopowder The negative impact caused by the volume visible light transmittance.

The core phase of the ATO-coated cesium tungsten bronze composite nanopowder is a hexagonal Cs _x WO ₃ cesium tungsten bronze phase without impurity phases.

Chemical resistance test: Weigh 2 g of the prepared ATO-coated cesium tungsten bronze composite nanopowder and put them into sodium hydroxide solution with a pH value of 8 and dilute hydrochloric acid solution with a pH value of 6. After stirring for 24 hours, the powder Body wash, dry. Detected by XRD, there was no change in the phase. It shows that the powder has excellent chemical resistance stability.

The preparation method of the described ATO-coated cesium tungsten bronze composite nanopowder comprises the following steps:

Step 1, preparation of cesium tungsten bronze precursor:

(1) Take tungsten source powder and cesium source powder, in molar ratio, tungsten source powder:cesium source powder=3:(0.3～1), weigh with electronic balance, dissolve the two into tungsten solution and cesium solution respectively Finally, mix it with the inducer evenly to obtain the A solution, and the added volume of the inducer is 15% to 25% of the volume sum of the tungsten solution and the cesium solution;

(2) Transfer the above-mentioned A solution to a hydrothermal kettle with a volume of 100ml, seal it and carry out hydrothermal reaction, the temperature is 200-240°C, and the reaction time is 10-16h;

(3) After the reaction is over, wait until the reactor is cooled to room temperature, and take out the precursor solution;

Step 2, cesium tungsten bronze powder preparation:

(1) Wash the precursor solution three times with deionized water and absolute ethanol, and perform multiple centrifugation operations;

(2) Dry in an oven at 60° C. for 12 hours to obtain a dark blue cesium tungsten bronze nanopowder Cs _x WO ₃ .

Step 3, preparation of ATO-coated cesium tungsten bronze composite nanopowder:

(1) dissolving the cesium tungsten bronze nanopowder in absolute ethanol, and adding a dispersant with a mass of 4-8% cesium tungsten bronze powder, and ultrasonically dispersing to form a stable suspension. The ultrasonic power is 10kHz-30KHz, The temperature is 25～60℃, and the time is 20～120min;

(2) In molar ratio, SnCl ₄ solution: SbCl ₃ solution=(8～11):1, mix the two evenly to obtain a clear mixed salt solution, and adjust the pH of the clear mixed salt solution to be 8～10;

(3) Under the condition of an oil bath temperature of 50-80°C, the ammonia solution and the mixed salt solution are slowly added dropwise to the stable suspension at the same time. According to the mass ratio, the solute in the mixed salt solution: cesium tungsten bronze powder = 0.5-0.7, And adjust the pH of the system to 2, use magnetic stirring to ensure the uniformity of the system during the reaction, and mature at 40-60°C for 2-4 hours after the precipitation is completed, so that the generated ATO is deposited on the surface of the cesium tungsten bronze powder core to form a coating layer, and the ATO-coated Cesium tungsten bronze composite nanopowder.

In the step 1(1), both the tungsten source powder and the cesium source powder are dissolved with organic alcohol.

In said step 1(1):

The cesium source is selected from at least one of cesium sulfate, cesium chloride, cesium hydroxide, and cesium carbonate, preferably cesium hydroxide;

The tungsten source is selected from at least one of sodium tungstate, tungsten hexachloride, ammonium tungstate, and ammonium metatungstate, preferably tungsten hexachloride;

Organic alcohol is selected from at least one of ethanol, ethylene glycol, glycerol, benzyl alcohol;

The inducer is at least one selected from glacial acetic acid, oleic acid, citric acid and ascorbic acid, preferably glacial acetic acid.

In the step 1(2), the cesium tungsten bronze inner core is formed by hydrothermal reaction based on the following chemical reaction formula:

CH ₃ CH ₂ OH+CH ₃ COOH=CH ₃ CH ₂ OOCCH ₃ +H ₂ O

2CH ₃ CH ₂ OH=CH ₃ CH ₂ OCH ₂ CH ₃ +H ₂ O

WCl ₆ +3H ₂ O=WO ₃ +6HCl

WO ₃ +xCsOH+x/4C ₂ H ₅ OH=Cs _x WO ₃ +x/4CH ₃ COOH+3x/4H ₂ O

In the step 2 (2), the particle size of the cesium tungsten bronze nanopowder Cs _x WO ₃ is 110-130 nm.

In the described step 3 (1), the dispersant is selected from at least one of polyvinyl alcohol PVA, polyethylene glycol PEG, sodium dodecylbenzenesulfonate SDBS, cetyltrimethylammonium bromide CTAB species, preferably polyethylene glycol PEG.

In the step 3(3), the general formula of ATO is Sb _x Sn _y O ₂ , wherein, x+y=1, y=0.9˜0.99.

In the step 3(3), the concentration of the ammonia solution is 1-3 mol/L.

In the step 3(2), the concentration of the SnCl ₄ solution is 0.125 mol/L, and the concentration of the SbCl ₃ solution is 0.167 mol/L.

In the step 3 (2), the ATO-coated cesium tungsten bronze composite nano-powder is used as an infrared barrier heat-insulation coating to prepare an infrared barrier heat-insulation film, and the visible light transmittance of the infrared barrier heat-insulation film is 32.85% ~79.80%, the absorption band in the near-infrared region is 780-2500nm, and the transmittance in the near-infrared region is ≤32%, showing a good combination of high transmittance of visible light and high absorptivity of near-infrared light. Specifically, the The transmittance of the infrared blocking and heat-insulating film is 75.20% to 79.80% when the wavelength is 390nm, the transmittance is 32.85% to 42.67% when the wavelength is 780nm, and the transmittance is 23.04% to 31.87% when the wavelength is 950nm. The transmittance at 1500nm is 11.03% to 18.99%, and the transmittance at 2500nm is 8.00% to 21.6%.

Beneficial effects of the present invention:

The present invention uses hydrothermal method and chemical hydrolysis method to prepare antimony-doped tin dioxide ATO-coated cesium tungsten bronze composite nano powder in two steps. This process has the advantages of simple control and simple process. The prepared composite nano powder It has excellent volume dispersibility and chemical stability, and can be widely used in infrared barrier energy-saving coatings and films.

The preparation method proposed by the invention is convenient for controlling the phase of the formed product, has simple and convenient process, high product yield, and is suitable for large-scale and low-cost production. The prepared composite powder has the outstanding advantages of excellent dispersion and high chemical stability. The composite powder of the invention can be widely used in the preparation of infrared-blocking and heat-insulating coatings or films.

Description of drawings:

Fig. 1 is the cesium tungsten bronze inner core powder X-ray diffraction (XRD) pattern prepared by the embodiment of the present invention 1;

Fig. 2 is a comparative diagram of the transmission spectra of the ATO-coated cesium tungsten bronze composite nanopowder prepared in Example 1 of the present invention and the cesium tungsten bronze nanomaterial infrared barrier diaphragm.

Detailed ways:

The present invention will be described in further detail below in conjunction with embodiment.

An oxide-coated cesium tungsten bronze composite nanopowder (referred to as "composite nanopowder", "nanopowder", "powder") according to an embodiment of the present invention includes a cesium tungsten bronze inner core and a cesium tungsten bronze coating Core of antimony-doped tin dioxide ATO shell.

The core of cesium tungsten bronze is Cs _x WO ₃ , where 0.1≤x≤0.33. The higher the value of x in this range, the stronger the absorption of infrared rays and the stronger the photothermal conversion effect of the powder. When used in infrared blocking and energy-saving fields (such as energy-saving coatings and films), it is recommended that x take the highest value.

The core of cesium tungsten bronze is a nanosphere with a particle size of 20-80nm.

In a preferred experimental mode, the thickness of the antimony-doped tin dioxide ATO shell is ≤30nm. At this thickness, the antimony-doped tin dioxide ATO shell is transparent, so that the visible light transmission performance of the coating or film prepared by using the composite powder is well maintained.

Specifically, the preparation of cesium tungsten bronze through a hydrothermal process based on the chemical reaction mechanism listed in the following formula is more convenient for simplifying the process, high yield, and stable preparation of cesium tungsten bronze.

CH ₃ CH ₂ OH+CH ₃ COOH=CH ₃ CH ₂ OOCCH ₃ +H ₂ O

2CH ₃ CH ₂ OH=CH ₃ CH ₂ OCH ₂ CH ₃ +H ₂ O

WCl ₆ +3H ₂ O=WO ₃ +6HCl

WO ₃ +xCsOH+x/4C ₂ H ₅ OH=Cs _x WO ₃ +x/4CH ₃ COOH+3x/4H ₂ O

In the reaction of this design, WCl ₆ is used as an oxidant to form the final cesium tungsten bronze phase together with other raw materials under high temperature hydrothermal action. The WCl ₆ is also a tungsten source at the same time, and the reaction cesium tungsten bronze has a clear formation mechanism, which can simplify the process, avoid the generation of by-products, increase the yield, facilitate the control of the reaction, and improve the stability of the reaction.

The cesium source (cesium hydroxide) in the formula is as reducing agent and cesium source, compares with existing use cesium oxide as the preparation method of reducing agent, avoids that cesium oxide is more lively, easily reacts with water, carbon dioxide etc. in the air And affect the measurement and operation.

In some embodiments, the cesium source can be selected from at least one of cesium sulfate, cesium chloride, cesium hydroxide, and cesium carbonate. Under the condition of maintaining equal substance equivalents, based on the principle shown in the chemical reaction formula, these raw materials can be combined arbitrarily without affecting the synthesis of cesium tungsten bronze powder.

The concentration of each raw material in the reaction system can be selected according to the desired final product concentration. The concentration of the final product formed has an effect on the dispersibility and particle size of the powder. Preferably, the concentration of the formed product is below 30%, so that the dispersibility of the powder can be better and the particle size distribution can be more uniform. More preferably, the concentration of the formed product is 10-20%.

The hydrothermal synthesis temperature for synthesizing cesium tungsten bronze is 220°C, and the synthesis time is 12h. When the hydrothermal synthesis temperature is increased, the time for its formation is shortened.

Based on the mechanism shown in the chemical reaction equation disclosed by the present invention, under the selected synthesis conditions, the batching is preferably carried out according to the stoichiometric ratio, and the yield of the obtained product is close to the theoretical value. Accordingly, the concentration of the product in the reaction system and the output of the cesium tungsten bronze powder can be controlled.

The test results show that the conversion rate of tungsten bronze after hydrothermal reaction is ≥99%.

In one embodiment of the present invention, the preparation of oxide-coated cesium tungsten bronze composite nanopowder mainly adopts the following steps by hydrothermal method and chemical hydrolysis method.

Cesium tungsten bronze precursor preparation:

(1) Take tungsten hexachloride and cesium hydroxide powder, weigh the two with an electronic balance at a molar ratio of 3:1, mix them evenly, and obtain A solution;

(2) Transfer the above-mentioned A solution to a 100ml volume hydrothermal kettle, seal it and heat it at 220°C, and the reaction time is 12h;

(3) After the reaction is completed, the precursor solution is taken out after the reactor is cooled to room temperature.

Cesium tungsten bronze powder preparation:

(1) Wash the obtained precursor solution with deionized water and absolute ethanol three times, and perform multiple centrifugation operations;

(2) Dry in an oven at 60° C. for 12 hours to obtain a dark blue nano Cs _0.33 WO ₃ powder sample.

Preparation of antimony-doped tin dioxide ATO-coated cesium tungsten bronze composite nanomaterials:

(1) Dissolve the obtained cesium tungsten bronze powder and one of the dispersants in absolute ethanol, and perform ultrasonic dispersion to form a stable suspension. The coating layer oxide salt and ammonia water are added dropwise to the suspension at the same time, the pH of the suspension is adjusted, and the oxide is deposited on the surface of the cesium tungsten bronze inner core to form a coating layer.

The above-mentioned composite nanometer material can be applied to infrared-blocking and heat-insulating coatings. The infrared-blocking and heat-insulating coating can be used to form an infrared-blocking and heat-insulating film.

Below, further examples are given to describe the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention, and cannot be interpreted as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art according to the above contents of the present invention all belong to the present invention protected range. The following: the specific process parameters of the examples are only an example of the suitable range, that is, those skilled in the art can make a selection within the suitable range through the description herein, and are not limited to the specific numerical values exemplified below.

Example 1:

1.5 mmol WCl ₆ was dissolved in 40 ml of absolute ethanol, and magnetically stirred at room temperature for 10 min to obtain a yellow solution. In a separate beaker, 0.5 mmol CsOH·H ₂ O was dispersed in 20 ml absolute ethanol. Add the obtained cesium hydroxide alcoholic solution and 12ml of glacial acetic acid into the tungsten hexachloride alcoholic solution to obtain a yellow solution. The solution was poured into a hydrothermal reaction kettle, and after the temperature was raised to 220° C., the reaction was carried out for 12 hours. After the reaction is finished, the precursor solution is taken out after the reactor is cooled to room temperature. The obtained precursor solution was washed three times with deionized water and absolute ethanol, and centrifuged several times; dried in an oven at 60°C for 12 hours to obtain a dark blue nano-Cs _0.33 WO ₃ powder sample with a particle size of 110-130nm.

Disperse 2 g of the cesium tungsten bronze powder in absolute ethanol, add a dispersant polyethylene glycol PEG with a mass fraction of 5%, stir thoroughly, and then ultrasonically disperse at 25kHZ and 40°C for 1 hour to obtain a uniform and stable suspension. Concentrations of 0.125mol/L and 0.167mol/L were mixed with SnCl ₄ and SbCl ₃ solutions in a ratio of 10:1 to obtain a uniform and clear mixed salt solution. Keep pH = 9, and 2mol/ L ammonia solution and mixed salt solution are slowly added dropwise to the suspension at the same time to keep the system PH=2, solute in the mixed salt solution: cesium tungsten bronze powder=0.5, use magnetic stirring to ensure that the system is uniform during the reaction, and collect the antimony-doped Tin dioxide ATO coated cesium tungsten bronze composite nanopowder, ATO composition is Sb _0.09 Sn _0..91 O ₂ .

Figure 1 is a powder X-ray diffraction (XRD) pattern of the prepared powder. It can be seen from Figure 1 that the obtained phase is a hexagonal Cs _0.33 WO ₃ cesium tungsten bronze phase, and no other impurity phases have been detected. The result of inductively coupled plasma mass spectrometry analysis on the supernatant was that the WO ₃ content was 0.066 wt%, indicating that the conversion rate of tungsten bronze after the hydrothermal reaction was ≥99%.

Fig. 2 is the comparison chart of transmittance spectra of the ATO-coated cesium tungsten bronze composite nanopowder and the cesium tungsten bronze inner core prepared in this example, wherein the transmittance of the composite nanopowder is 79.80% when the wavelength is 390nm, and the wavelength The transmittance is 38.53% at 780nm, 23.04% at 950nm, 12.00% at 1500nm, and 8.00% at 2500nm.

The particle size range of the composite nanopowder obtained in this example is 20-45 nm. Weigh 2 g of the prepared zinc oxide-coated cesium tungsten bronze composite nanomaterial and put them into sodium hydroxide solution with a pH value of 8 and a dilute hydrochloric acid solution with a pH value of 6. After stirring for 24 hours, the powder is washed and dried. Detected by XRD, there is no change in the phase. It shows that the powder has excellent chemical resistance stability.

Example 2:

Dissolve 1.5mmol WCl ₆ in 40ml absolute ethanol, and stir magnetically for 10min at room temperature to obtain a yellow solution. In a separate beaker, disperse 0.25mmoCsOH· _H2O in 20ml absolute ethanol. Add the obtained cesium hydroxide alcoholic solution and 12ml of glacial acetic acid into the tungsten hexachloride alcoholic solution to obtain a yellow solution. The solution was poured into a hydrothermal reaction kettle, and the temperature was raised to 240° C., and reacted for 10 hours. After the reaction is finished, the precursor solution is taken out after the reactor is cooled to room temperature. The resulting precursor solution was washed three times with deionized water and absolute ethanol, and centrifuged several times; dried in an oven at 60°C for 12 hours to obtain a dark blue nano-Cs _0.17 WO ₃ powder sample with a particle size of 110-130nm.

Disperse 2 g of the cesium tungsten bronze powder in absolute ethanol, add polyethylene glycol PEG as a dispersant with a mass fraction of 5%, stir thoroughly at 25kHZ, 40°C, and then ultrasonically disperse for 1 hour to obtain a uniform and stable suspension , take concentrations of 0.125mol/L and 0.167mol/L respectively in the ratio of 10.5:1 SnCl ₄ and SbCl ₃ solutions and mix to obtain a uniform and clear mixed salt solution, keep pH = 8, under the condition of oil bath temperature 60 ℃ 2mol/L ammonia solution and mixed salt solution are slowly added dropwise to the suspension at the same time to keep the system pH=2, the solute in the mixed salt solution: cesium tungsten bronze powder=0.5, use magnetic stirring to ensure that the system is uniform during the reaction, and collect the Antimony-doped tin dioxide ATO coated cesium tungsten bronze composite nanopowder, ATO composition is Sb _0.05 Sn _0..95 O ₂ .

The particle size of the composite nanopowder obtained in this example is 25-50 nm. The result of inductively coupled plasma mass spectrometry analysis on the supernatant was that the WO ₃ content was 0.066 wt%, indicating that the conversion rate of tungsten bronze after the hydrothermal reaction was ≥99%. The chemical resistance stability is similar to that of Example 1, but due to the decreased content of Cs and Sb, the near-infrared absorption performance of the composite nanomaterial in this example decreases.

Among them, the transmittance of the composite powder is 75.20% when the wavelength is 390nm, the transmittance is 32.85% when the wavelength is 780nm, the transmittance is 31.87% when the wavelength is 950nm, and the transmittance is 18.99% when the wavelength is 1500nm. The transmittance is 21.6% at 2500nm.

Example 3

1.5 mmol WCl ₆ was dissolved in 40 ml of absolute ethanol, and magnetically stirred at room temperature for 10 min to obtain a yellow solution. In a separate beaker, 0.375 mmol CsOH·H ₂ O was dispersed in 20 ml absolute ethanol. Add the obtained cesium hydroxide alcoholic solution and 12ml of glacial acetic acid into the tungsten hexachloride alcoholic solution to obtain a yellow solution. The solution was poured into a hydrothermal reaction kettle, and the temperature was raised to 240° C., and reacted for 10 h. After the reaction is finished, the precursor solution is taken out after the reactor is cooled to room temperature. The resulting precursor solution was washed three times with deionized water and absolute ethanol, and centrifuged several times; dried in an oven at 60°C for 12 hours to obtain a dark blue nano-Cs _0.25 WO ₃ powder sample with a particle size of 110-130nm.

Disperse 2 g of the cesium tungsten bronze powder in absolute ethanol, add a dispersant polyethylene glycol PEG with a mass fraction of 5%, stir thoroughly, and then ultrasonically disperse at 25kHZ and 40°C for 1 hour to obtain a uniform and stable suspension. Concentrations of 0.125mol/L and 0.167mol/L were mixed with SnCl ₄ and SbCl ₃ solutions in a ratio of 10:1 to obtain a uniform and clear mixed salt solution. Keep pH = 9, and 2mol/ L ammonia solution and mixed salt solution are slowly added dropwise to the suspension at the same time to keep the system pH=2, solute in the mixed salt solution: cesium tungsten bronze powder=0.5, use magnetic stirring to ensure that the system is uniform during the reaction, and collect the antimony-doped Tin dioxide ATO coated cesium tungsten bronze composite nanopowder, ATO composition is Sb _0.09 Sn _0..91 O ₂ .

The particle size of the composite nanopowder obtained in this example is 25-50 nm. The result of inductively coupled plasma mass spectrometry analysis on the supernatant was that the WO ₃ content was 0.066 wt%, indicating that the conversion rate of tungsten bronze after the hydrothermal reaction was ≥99%. The chemical resistance stability is similar to that of Example 1, but because the Cs content is lower than that of Example 1, the visible light transmittance of the composite nanomaterial in this example decreases.

Among them, the transmittance of the composite powder is 77.32% when the wavelength is 390nm, the transmittance is 35.94% when the wavelength is 780nm, the transmittance is 26.88% when the wavelength is 950nm, and the transmittance is 16.07% when the wavelength is 1500nm. The transmittance is 9.66% at 2500nm.

Example 4

1.5 mmol WCl ₆ was dissolved in 40 ml of absolute ethanol, and magnetically stirred at room temperature for 10 min to obtain a yellow solution. In a separate beaker, 0.5 mmol CsOH·H ₂ O was dispersed in 25 ml absolute ethanol. Add the obtained cesium hydroxide alcoholic solution and 13ml of glacial acetic acid into the tungsten hexachloride alcoholic solution to obtain a yellow solution. The solution was poured into a hydrothermal reaction kettle, and after the temperature was raised to 220° C., the reaction was carried out for 12 hours. After the reaction is finished, the precursor solution is taken out after the reactor is cooled to room temperature. The obtained precursor solution was washed three times with deionized water and absolute ethanol, and centrifuged several times; dried in an oven at 60°C for 12 hours to obtain a dark blue nano-Cs _0.33 WO ₃ powder sample with a particle size of 110-130nm.

Disperse 2 g of the cesium tungsten bronze powder in absolute ethanol, add a dispersant polyethylene glycol PEG with a mass fraction of 5%, stir thoroughly, and then ultrasonically disperse at 25kHZ and 40°C for 40 minutes to obtain a suspension. The concentrations are respectively 0.125mol/L and 0.167mol/L ratio of 10:1 SnCl ₄ and SbCl ₃ solution mixed to obtain a uniform and clear mixed salt solution, keep pH = 9, under the condition of oil bath temperature 60 ℃, 2mol/L ammonia solution Slowly add the mixed salt solution into the suspension at the same time, keep the system pH=2, the solute in the mixed salt solution: cesium tungsten bronze powder=0.55, use magnetic stirring to ensure the uniformity of the system during the reaction, and collect the antimony-doped tin dioxide ATO coated cesium tungsten bronze composite nanopowder, ATO composition is Sb _0.09 Sn _0..91 O ₂ .

The particle size of the composite nanopowder obtained in this example is 25-55 nm. The result of inductively coupled plasma mass spectrometry analysis on the supernatant was that the WO ₃ content was 0.066 wt%, indicating that the conversion rate of tungsten bronze after the hydrothermal reaction was ≥99%. The chemical resistance stability is similar to that of Example 1, but due to the short ultrasonic dispersion time, the agglomeration phenomenon of the cesium tungsten bronze core has not been well improved, and the visible light transmission performance of the composite nanomaterial in this example has declined.

Among them, the transmittance of the composite powder is 76.22% when the wavelength is 390nm, the transmittance is 34.99% when the wavelength is 780nm, the transmittance is 26.95% when the wavelength is 950nm, and the transmittance is 14.08% when the wavelength is 1500nm. The transmittance is 9.30% at 2500nm.

Example 5

1.5 mmol WCl ₆ was dissolved in 40 ml of absolute ethanol, and magnetically stirred at room temperature for 10 min to obtain a yellow solution. In a separate beaker, 0.5 mmol CsOH·H ₂ O was dispersed in 20 ml absolute ethanol. Add the obtained cesium hydroxide alcoholic solution and 12ml of glacial acetic acid into the tungsten hexachloride alcoholic solution to obtain a yellow solution. The solution was poured into a hydrothermal reaction kettle, and after the temperature was raised to 220° C., the reaction was carried out for 12 hours. After the reaction is finished, the precursor solution is taken out after the reactor is cooled to room temperature. The obtained precursor solution was washed three times with deionized water and absolute ethanol, and centrifuged several times; dried in an oven at 60°C for 12 hours to obtain a dark blue nano-Cs _0.33 WO ₃ powder sample with a particle size of 110-130nm.

Disperse 2 g of the cesium tungsten bronze powder in absolute ethanol, add a dispersant polyvinyl alcohol PVA with a mass fraction of 5%, stir thoroughly, and then ultrasonically disperse at 25kHZ and 40°C for 1 hour to obtain a uniform and stable suspension. The ratio of 0.125mol/L and 0.167mol/L respectively is 10:1 SnCl ₄ and SbCl ₃ solutions are mixed to obtain a uniform and clear mixed salt solution, keep pH=9, and 2mol/L The ammonia solution and the mixed salt solution are slowly added dropwise to the suspension at the same time to keep the pH of the system=2, the solute in the mixed salt solution: cesium tungsten bronze powder=0.5, use magnetic stirring to ensure that the system is uniform during the reaction, and collect the antimony-doped bismuth Tin oxide ATO coated cesium tungsten bronze composite nanopowder, ATO composition is Sb _0.09 Sn _0..91 O ₂ .

The particle size of the composite nanopowder obtained in this example is 30-50 nm. The result of inductively coupled plasma mass spectrometry analysis on the supernatant was that the WO ₃ content was 0.066 wt%, indicating that the conversion rate of tungsten bronze after the hydrothermal reaction was ≥99%. Chemical stability is similar to Example 1.

Among them, the transmittance of the composite powder is 78.63% when the wavelength is 390nm, the transmittance is 42.67% when the wavelength is 780nm, the transmittance is 24.01% when the wavelength is 950nm, and the transmittance is 11.03% when the wavelength is 1500nm. The transmittance is 8.16% at 2500nm.

Comparative example 1:

Dissolve 1.5mmol WCl ₆ in 40ml absolute ethanol, and stir magnetically for 10min at room temperature to obtain a yellow solution. In a separate beaker, disperse 0.15mmoCsOH· _H2O in 20ml absolute ethanol. Add the obtained cesium hydroxide alcoholic solution and 12ml of glacial acetic acid into the tungsten hexachloride alcoholic solution to obtain a yellow solution. The solution was poured into a hydrothermal reaction kettle, and the temperature was raised to 220° C., and reacted for 10 h. After the reaction is finished, the precursor solution is taken out after the reactor is cooled to room temperature. The resulting precursor solution was washed three times with deionized water and absolute ethanol, and centrifuged several times; dried in an oven at 60°C for 12 hours to obtain a dark blue nano-Cs _0.1 WO ₃ powder sample.

Disperse 2 g of the cesium tungsten bronze powder in absolute ethanol, add polyvinyl alcohol (PVA) with a mass fraction of 5%, and ultrasonically disperse for 1 hour at 25kHZ and 40°C to obtain a uniform and stable suspension. The ratio of 0.125mol/L and 0.167mol/L respectively is 10:1 SnCl ₄ and SbCl ₃ solutions are mixed to obtain a uniform and clear mixed salt solution, keep pH=9, and 2mol/L The ammonia solution and the mixed salt solution are slowly added dropwise to the suspension at the same time to keep the pH of the system=2, the solute in the mixed salt solution: cesium tungsten bronze powder=0.5, use magnetic stirring to ensure that the system is uniform during the reaction, and collect the antimony-doped bismuth Tin oxide ATO coated cesium tungsten bronze composite nanopowder, ATO composition is Sb _0.09 Sn _0..91 O ₂ .

The particle size of the composite nanopowder obtained in this example is 25-50 nm. The result of inductively coupled plasma mass spectrometry analysis on the supernatant was that the WO ₃ content was 0.066 wt%, indicating that the conversion rate of tungsten bronze after the hydrothermal reaction was ≥99%. The chemical resistance stability is similar to that of Example 1, but due to the decreased content of Cs and Sb, the near-infrared absorption performance of the composite nanomaterial in this example is poor.

Among them, the transmittance of the composite powder is 68.50% when the wavelength is 390nm, the transmittance is 25.62% when the wavelength is 780nm, the transmittance is 39.91% when the wavelength is 950nm, and the transmittance is 26.09% when the wavelength is 1500nm. The transmittance is 33.96% at 2500nm.

Comparative example 2

1.5 mmol WCl ₆ was dissolved in 40 ml of absolute ethanol, and magnetically stirred at room temperature for 10 min to obtain a yellow solution. In a separate beaker, 0.5 mmol CsOH·H ₂ O was dispersed in 25 ml absolute ethanol. Add the obtained cesium hydroxide alcoholic solution and 13ml of glacial acetic acid into the tungsten hexachloride alcoholic solution to obtain a yellow solution. The solution was poured into a hydrothermal reaction kettle, and after the temperature was raised to 220° C., the reaction was carried out for 12 hours. After the reaction is finished, the precursor solution is taken out after the reactor is cooled to room temperature. The resulting precursor solution was washed three times with deionized water and absolute ethanol, and centrifuged several times; dried in an oven at 60°C for 12 hours to obtain a dark blue nano-Cs _0.33 WO ₃ powder sample.

Disperse 2 g of the cesium tungsten bronze powder in absolute ethanol, add a dispersant polyethylene glycol PEG with a mass fraction of 5%, stir thoroughly at 25kHZ, 40°C, and then ultrasonically disperse for 1 hour to obtain a uniform and stable suspension. Take 0.125mol/L and 0.167mol/L of SnCl ₄ and SbCl ₃ solutions with a ratio of 15:1 and mix them to obtain a uniform and clear mixed salt solution, keep pH=9, and add 2mol /L ammonia solution and mixed salt solution are slowly added dropwise to the suspension simultaneously to keep the system pH=2, solute in the mixed salt solution: cesium tungsten bronze powder=0.5, ensure that the system is even with magnetic stirring in the reaction process, collect the mixed Antimony tin dioxide ATO coated cesium tungsten bronze composite nanopowder, ATO composition is Sb _0.06 Sn _0..94 O ₂ .

The particle size of the composite nanopowder obtained in this example is 30-50 nm. Among them, the transmittance of the composite powder is 67.56% when the wavelength is 390nm, the transmittance is 30.78% when the wavelength is 780nm, the transmittance is 29.68% when the wavelength is 950nm, and the transmittance is 25.63% when the wavelength is 1500nm. The transmittance is 31.96% at 2500nm.

Comparative example 3

1.5 mmol WCl ₆ was dissolved in 40 ml of absolute ethanol, and magnetically stirred at room temperature for 10 min to obtain a yellow solution. In a separate beaker, 0.5 mmol CsOH·H ₂ O was dispersed in 20 ml absolute ethanol. Add the obtained cesium hydroxide alcoholic solution and 12ml of glacial acetic acid into the tungsten hexachloride alcoholic solution to obtain a yellow solution. The solution was poured into a hydrothermal reaction kettle, and after the temperature was raised to 220° C., the reaction was carried out for 12 hours. After the reaction is finished, the precursor solution is taken out after the reactor is cooled to room temperature. The resulting precursor solution was washed three times with deionized water and absolute ethanol, and centrifuged several times; dried in an oven at 60°C for 12 hours to obtain a dark blue nano-Cs _0.33 WO ₃ powder sample.

Disperse 2 g of the cesium tungsten bronze powder in absolute ethanol, add a dispersant polyethylene glycol PEG with a mass fraction of 5%, stir thoroughly, and then ultrasonically disperse at 8kHZ, 40°C for 1 hour to obtain a uniform and stable suspension. Concentrations of 0.125mol/L and 0.167mol/L were mixed with SnCl ₄ and SbCl ₃ solutions in a ratio of 10:1 to obtain a uniform and clear mixed salt solution. Keep pH = 9, and 2mol/ L ammonia solution and mixed salt solution are slowly added dropwise to the suspension at the same time to keep the system pH=2, the solute in the mixed salt solution: cesium tungsten bronze powder=0.55, use magnetic stirring to ensure that the system is uniform during the reaction, and collect the antimony-doped Tin dioxide ATO coated cesium tungsten bronze composite nanopowder, ATO composition is Sb _0.09 Sn _0..91 O ₂ .

The particle size of the composite nanopowder obtained in this example is 35-60 nm. Due to the low frequency of ultrasonic dispersion, cesium tungsten bronze nanoparticles still have agglomeration phenomenon, which cannot guarantee good monodispersity of only one cesium tungsten bronze core in a cladding layer. The transmittance of the composite powder is 390nm. 58.64%, the transmittance is 33.52% when the wavelength is 780nm, the transmittance is 29.01% when the wavelength is 950nm, the transmittance is 20.33% when the wavelength is 1500nm, and the transmittance is 22.81% when the wavelength is 2500nm.

Claims (6)

1. A preparation method for ATO-coated cesium tungsten bronze composite nano-powder, characterized in that, said ATO-coated cesium tungsten bronze composite nano-powder comprises a cesium tungsten bronze core and a cesium tungsten bronze core that coats said cesium tungsten bronze core. ATO shell, the general formula of the cesium tungsten bronze core is Cs _x WO ₃ , where 0.1≤x≤0.33, the cesium tungsten bronze core is a nanosphere with a particle size of 20~80nm; the thickness of the ATO shell is ≤30nm; the core phase of the ATO-coated cesium tungsten bronze composite nanopowder is a hexagonal Cs _x WO ₃ cesium tungsten bronze phase, without impurities; Described preparation method comprises the following steps: Step 1, preparation of cesium tungsten bronze precursor: (1) Take tungsten source powder and cesium source powder, according to the molar ratio, tungsten source powder:cesium source powder=3:(0.3~1), weigh them with an electronic balance, and dissolve the two into tungsten solution and cesium solution respectively Afterwards, mix with the inducer evenly to obtain A solution, the tungsten source is selected from at least one of sodium tungstate, tungsten hexachloride, ammonium tungstate, ammonium metatungstate, and the inducer is selected from glacial acetic acid, oil At least one of acid, citric acid, and ascorbic acid, and the volume of the inducer added is 15% to 25% of the volume sum of the tungsten solution and the cesium solution; (2) Transfer the above-mentioned A solution to a 100ml hydrothermal kettle, seal it for hydrothermal reaction, the temperature is 200~240℃, and the reaction time is 10~16 h; (3) After the reaction is over, wait until the reactor is cooled to room temperature, and take out the precursor solution; Step 2, cesium tungsten bronze powder preparation: (1) Wash the precursor solution three times with deionized water and absolute ethanol, and perform multiple centrifugation operations; (2) drying in an oven at 60° C. for 12 hours to obtain dark blue cesium tungsten bronze nanopowder Cs _x WO ₃ ; Step 3, preparation of ATO-coated cesium tungsten bronze composite nanopowder: (1) Dissolve the cesium tungsten bronze nanopowder in absolute ethanol, and add a dispersant with a mass of 4~8% of the cesium tungsten bronze powder, and perform ultrasonic dispersion to form a stable suspension. The ultrasonic power is 10kHz~30KHz, The temperature is 25~60℃, and the time is 20~120min; (2) In molar ratio, SnCl ₄ solution: SbCl ₃ solution=(8~11):1, mix the two evenly to obtain a clear mixed salt solution, and adjust the pH of the clear mixed salt solution to be 8~10; (3) Under the condition of an oil bath temperature of 50~80°C, slowly add the ammonia solution and the mixed salt solution dropwise into the stable suspension at the same time. According to the mass ratio, the solute in the mixed salt solution: cesium tungsten bronze powder=0.5~0.7, And adjust the pH of the system to 2. During the reaction process, use magnetic stirring to ensure that the system is uniform. After the precipitation is completed, it is aged at 40-60°C for 2-4 hours, so that the generated ATO is deposited on the surface of the cesium tungsten bronze powder core to form a coating layer, and ATO is obtained. Coated cesium tungsten bronze composite nanopowder. 2. the preparation method of ATO coating cesium tungsten bronze composite nanopowder according to claim 1 is characterized in that, in described step 1 (1), cesium source is selected from cesium sulfate, cesium chloride, hydroxide At least one of cesium and cesium carbonate. 3. the preparation method of ATO coating cesium tungsten bronze composite nanopowder according to claim 1, is characterized in that, in described step 2 (2), cesium tungsten bronze nanopowder Cs _x WO ₃ particle size is 110~130nm. 4. the preparation method of ATO coating cesium tungsten bronze composite nanopowder according to claim 1 is characterized in that, in described step 3 (1), dispersant is selected from polyvinyl alcohol PVA, polyethylene glycol At least one of PEG, sodium dodecylbenzenesulfonate SDBS, and cetyltrimethylammonium bromide CTAB. 5. the preparation method of ATO coating cesium tungsten bronze composite nano-powder according to claim 1, is characterized in that, in described step 3 (3), the general formula of ATO is Sb _x Sn _y O ₂ , wherein , x+y=1, y=0.9~0.99. 6. the preparation method of ATO-coated cesium-tungsten bronze composite nano-powder according to claim 1, is characterized in that, in described step 3 (2), ATO-coated cesium-tungsten bronze composite nano-powder is used as infrared barrier Heat-insulating coating, preparing an infrared-blocking heat-insulating film, the visible light transmittance of the infrared-blocking heat-insulating film is 32.85% to 79.80%, the absorption band in the near-infrared light region is 780-2500nm, and the transmittance in the near-infrared light region is ≤ 32%, specifically, the transmittance of the infrared blocking and heat-insulating film is 75.20%~79.80% when the wavelength is 390nm, the transmittance is 32.85%~42.67% when the wavelength is 780nm, and the transmittance is 32.85%~42.67% when the wavelength is 950nm The transmittance is 23.04%~31.87%, the transmittance is 11.03%~18.99% when the wavelength is 1500nm, and the transmittance is 8.00%~21.6% when the wavelength is 2500nm.

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