阅读说明：本技术 一种低温制备纳米ito粉末的方法 (Method for preparing nano ITO powder at low temperature ) 是由 唐智勇 于 2021-02-02 设计创作，主要内容包括：本发明公开了一种低温制备纳米ITO粉末的方法,属于纳米ITO粉末加工技术领域,该方法包括以下步骤：S1、王水溶液的配制：将浓盐酸和浓硝酸按容积比l:3配成王水溶液；S2、溶解、混合：取40ml王水溶液,然后称取10-20g金属铟和3-5g四氯化锡使其依次溶于王水溶液中,搅拌均匀后,备用,得到混合物；S3、共沉淀：在搅拌下,将氢氧化钠溶液加入到步骤S2得到的混合物中,两者共沉淀后,得到氢氧化铟和氢氧化锡的胶体前驱物；S4、过滤、洗涤：用蒸馏水洗涤步骤S3得到的胶体前驱物2-4次,得到铟锡氢氧化物；S5、反应。本发明解决了现有水热法制备工艺对设备耐温能力要求高的问题。(The invention discloses a method for preparing nano ITO powder at low temperature, belonging to the technical field of nano ITO powder processing, comprising the following steps: s1, preparing aqua regia solution: preparing concentrated hydrochloric acid and concentrated nitric acid into aqua regia solution according to the volume ratio l: 3; s2, dissolving and mixing: taking 40ml of aqua regia solution, then weighing 10-20g of metal indium and 3-5g of stannic chloride to be sequentially dissolved in the aqua regia solution, and uniformly stirring for later use to obtain a mixture; s3, coprecipitation: adding a sodium hydroxide solution into the mixture obtained in the step S2 under stirring, and obtaining a colloid precursor of indium hydroxide and tin hydroxide after the sodium hydroxide solution and the mixture are subjected to coprecipitation; s4, filtering and washing: washing the colloid precursor obtained in the step S3 with distilled water for 2-4 times to obtain indium tin oxide; and S5, reacting. The invention solves the problem that the existing hydrothermal method preparation technology has high requirement on the temperature resistance of equipment.)

1. A method for preparing nano ITO powder at low temperature is characterized in that: the method comprises the following steps:

s1 preparation of aqua regia solution

Preparing 80ml of aqua regia solution from concentrated hydrochloric acid and concentrated nitric acid according to the volume ratio of l: 3;

s2, dissolving and mixing

Taking 40ml of aqua regia solution, then weighing 10-20g of metal indium and 3-5g of stannic chloride to be sequentially dissolved In the aqua regia solution, and uniformly stirring for later use to obtain In₂O₃：SnO₂A mixture of (8-10): l by weight;

s3 coprecipitation

Adding a sodium hydroxide solution into the mixture obtained in the step S2 under stirring, and obtaining a colloid precursor of indium hydroxide and tin hydroxide after the sodium hydroxide solution and the mixture are subjected to coprecipitation;

s4, filtering and washing

Washing the colloid precursor obtained in the step S3 with distilled water for 2-4 times to obtain indium tin oxide;

s5, reaction

Drying the indium tin hydroxide obtained in the step S4 at 90-110 ℃ for 4h, then placing the dried precursor into a high-pressure kettle, filling argon gas with the pressure of 0.8MPa, and then placing the high-pressure kettle on an electric furnace for heating; when the temperature rises to 250 ℃, the pressure is 1.5MPa, then the autoclave is deflated again until the pressure in the autoclave is reduced to 1.0MPa, the temperature is continuously raised to 300 ℃, the reaction is continued for 4 hours, and after the reaction is finished, the autoclave is taken out and naturally cooled to the normal temperature, so that the ITO nano-particles are obtained.

2. The method for preparing nano ITO powder at low temperature according to claim 1, wherein: in step S4, the colloidal precursor obtained in step S3 is washed with distilled water 2-4 times until AgNO is used₃The colloidal precursor is detected to be Cl-free by the solution^-。

3. The method for preparing nano ITO powder at low temperature according to claim 1, wherein: in step S5, when the temperature rises to 250 ℃, the pressure is 1.5MPa, then the autoclave is deflated again until the pressure in the autoclave is reduced to 1.0MPa, the temperature is continuously raised to 300 ℃, the pressure in the autoclave is observed, the pressure in the autoclave is maintained to be 1.0MPa by repeated deflation, and the reaction is continued for 4 hours.

4. The method for preparing nano ITO powder at low temperature according to any one of claims 1 to 3, wherein: the autoclave comprises an autoclave body (1), a cover plate (2), a heat exchanger (5), a walking device (9) and a mounting plate (10);

the cover plate (2) is covered on the top of the kettle body (1), an air discharging pipe (3) is connected between the kettle body (1) and the heat exchanger (5), a switch valve (4) is installed on the air discharging pipe (3), a cold fluid inlet (7) for cold medium to enter and exit, a cold fluid outlet (6) and an exhaust pipe (8) for gas to be discharged are arranged on the heat exchanger (5), and the exhaust pipe (8) is used for guiding the gas after heat exchange to a high place to be discharged;

the walking device (9) is used for evacuating the gas exhausted by the exhaust pipe (8) so as to uniformly diffuse the gas all around, and the walking device (9) is fixed on the mounting plate (10).

5. The method for preparing nano ITO powder at low temperature according to claim 4, wherein: the walking device (9) comprises an exhaust tube (91), an exhaust hood (92), a movable rod (93), a spring (95) and a fixed block (98);

the upper end and the lower end of the exhaust funnel (91) are both provided with openings, the upper end of the exhaust funnel (91) is fixed on the mounting plate (10), the exhaust hood (92) is positioned below the exhaust funnel (91) and covers the exhaust port of the exhaust pipe (8), the fixing block (98) is positioned in the exhaust funnel (91) and fixed on the exhaust hood (92), the exhaust hood (92) is provided with a through hole (97), and the through hole (97) penetrates through the fixing block (98) and the exhaust hood (92) so that gas enters the exhaust funnel (91) through the through hole (97);

spring (95) are located in aiutage (91) and the lower extreme is fixed on fixed block (98), and the upper end is fixed on mounting panel (10), aiutage (91) circumference surface is offered and is used for gaseous outside exhaust grid hole (94), movable rod (93) one end is fixed on fixed block (98), and the other end passes grid hole (94), grid hole (94) length direction with aiutage (91) axial direction is unanimous, so that movable rod (93) are in reciprocate in grid hole (94).

6. The method for preparing nano ITO powder at low temperature according to claim 5, wherein: the exhaust hood (92) is of an inverted funnel shape and has a circular top view projection.

7. The method for preparing nano ITO powder at low temperature according to claim 6, wherein: the exhaust hood (92) is made of soft rubber, a plurality of notches (96) are formed in the exhaust hood (92), the notches (96) are evenly distributed on the exhaust hood (92) by taking the center of the exhaust hood (92) as the center of a circle, and the notches (96) are fan-shaped notches and two straight lines are arranged around the through hole (97).

8. The method for preparing nano ITO powder at low temperature according to claim 5, wherein: the grid holes (94) are arranged in a plurality, and the grid holes (94) are uniformly distributed around the exhaust funnel (91).

9. The method for preparing nano ITO powder at low temperature according to claim 4, wherein: the mounting plate (10) is provided with mounting holes, so that the mounting plate (10) is connected to an indoor ceiling or a wall body through the mounting holes in a bolted mode.

10. The method for preparing nano ITO powder at low temperature according to claim 4, wherein: the cold medium is circulating water.

Technical Field

The invention relates to the technical field of nano ITO powder processing, in particular to a method for preparing nano ITO powder at low temperature.

Background

Indium Tin Oxide (ITO) is an important semiconductor ceramic material, and the main component is In₂O₃、SnO₂The conductivity is enhanced by doping tetravalent tin into the indium oxide lattice. The ITO film has wide application prospect in the high-technology fields of photoelectrons, sensors, solar energy, wide-spectrum stealth and the like due to the excellent comprehensive properties of transparency, conductivity, heat insulation, infrared reflection, radar wave transmission and the like, and can be used as an electrode of electrochemical reaction to effectively decompose industrial waste. Adopts ITO target material channelThe ITO thin film prepared by vacuum coating and other ways has become an indispensable key material for flat panel displays such as TFT-LCD, PDP and the like, and the ITO target is promoted to develop into a remarkable strategic high-tech industry. The nano ITO powder is used as the basis of the whole ITO industrial chain, can be sputtered into an ITO film through a target material, can be applied to a coating in a grouting mode, and can also be directly used for preparing a nano composite material, so that the application prospect is good. Therefore, the development of the nano ITO powder preparation technology with simple process, high yield, environmental friendliness and excellent product is very important for the development of ITO and downstream industries.

The hydrothermal method is to heat and create a high-temperature and high-pressure environment in a sealed pressure container, so that the salt solution of indium and tin reacts in an alkaline environment, thereby preparing the nano powder. The method has simple process, does not need high-temperature roasting treatment, has good powder dispersion performance, almost has no agglomeration or only weak agglomeration, but has lower yield and high requirements on the temperature resistance and pressure resistance of equipment.

In order to optimize the hydrothermal process and reduce the dependence on production equipment, the invention provides a method for preparing nano ITO powder at low temperature.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for preparing nano ITO powder at a low temperature, which solves the problem that the existing hydrothermal preparation process has high requirement on the temperature resistance of equipment.

In order to achieve the purpose, the invention provides the following technical scheme:

a method for preparing nano ITO powder at low temperature comprises the following steps:

s1 preparation of aqua regia solution

Preparing 80ml of aqua regia solution from concentrated hydrochloric acid and concentrated nitric acid according to the volume ratio of l: 3;

s2, dissolving and mixing

Taking 40ml of aqua regia solution, then weighing 10-20g of metal indium and 3-5g of stannic chloride to be sequentially dissolved In the aqua regia solution, and uniformly stirring for later use to obtain In₂O₃：SnO₂A mixture of (8-10): l by weight;

s3 coprecipitation

Adding a sodium hydroxide solution into the mixture obtained in the step S2 under stirring, and obtaining a colloid precursor of indium hydroxide and tin hydroxide after the sodium hydroxide solution and the mixture are subjected to coprecipitation;

s4, filtering and washing

Washing the colloid precursor obtained in the step S3 with distilled water for 2-4 times to obtain indium tin oxide;

s5, reaction

Drying the indium tin hydroxide obtained in the step S4 at 90-110 ℃ for 4h, then placing the dried precursor into a high-pressure kettle, filling argon gas with the pressure of 0.8MPa, and then placing the high-pressure kettle on an electric furnace for heating; when the temperature rises to 250 ℃, the pressure is 1.5MPa, then the autoclave is deflated again until the pressure in the autoclave is reduced to 1.0MPa, the temperature is continuously raised to 300 ℃, the reaction is continued for 4 hours, and after the reaction is finished, the autoclave is taken out and naturally cooled to the normal temperature, so that the ITO nano-particles are obtained.

More preferably: in step S4, the colloidal precursor obtained in step S3 is washed with distilled water 2-4 times until AgNO is used₃The colloidal precursor is detected to be Cl-free by the solution^-。

More preferably: in step S5, when the temperature rises to 250 ℃, the pressure is 1.5MPa, then the autoclave is deflated again until the pressure in the autoclave is reduced to 1.0MPa, the temperature is continuously raised to 300 ℃, the pressure in the autoclave is observed, the pressure in the autoclave is maintained to be 1.0MPa by repeated deflation, and the reaction is continued for 4 hours.

More preferably: the autoclave comprises an autoclave body, a cover plate, a heat exchanger, a walking device and a mounting plate;

the cover plate is covered on the top of the kettle body, a gas discharging pipe is connected between the kettle body and the heat exchanger, a switch valve is installed on the gas discharging pipe, a cold fluid inlet and a cold fluid outlet for cold medium to enter and exit and a gas discharging pipe for gas to be discharged are arranged on the heat exchanger, and the gas after heat exchange is guided to a high place to be discharged;

the walking device is used for evacuating the gas exhausted by the exhaust pipe so as to uniformly diffuse the gas all around, and the walking device is fixed on the mounting plate.

More preferably: the walking device comprises an exhaust funnel, an exhaust hood, a movable rod, a spring and a fixed block;

the upper end and the lower end of the exhaust funnel are both provided with openings, the upper end of the exhaust funnel is fixed on the mounting plate, the exhaust hood is positioned below the exhaust funnel and covers the exhaust port of the exhaust pipe, the fixed block is positioned in the exhaust funnel and fixed on the exhaust hood, the exhaust hood is provided with a through hole, and the through hole penetrates through the fixed block and the exhaust hood so that gas enters the exhaust funnel through the through hole;

the spring is located in the aiutage and the lower extreme is fixed on the fixed block, and the upper end is fixed on the mounting panel, the aiutage circumference surface is offered and is used for the outside exhaust grid hole of gas, movable rod one end is fixed on the fixed block, and the other end passes the grid hole, grid hole length direction with aiutage axial direction is unanimous, so that the movable rod is in downthehole reciprocating of grid.

More preferably: the exhaust hood is of an inverted funnel shape and has a circular top view projection.

More preferably: the exhaust hood is made of soft rubber, a plurality of gaps are formed in the exhaust hood, the gaps are evenly distributed on the exhaust hood by taking the center of the exhaust hood as a circle center, and the gaps are fan-shaped gaps and two straight lines of included angles are located around the through holes.

More preferably: the grid hole is provided with a plurality ofly, a plurality ofly the grid hole equipartition is in exhaust stack is all around.

More preferably: the mounting plate is provided with mounting holes, so that the mounting plate is connected to an indoor ceiling or a wall body through bolts through the mounting holes.

More preferably: the cold medium is circulating water.

In conclusion, the invention has the following beneficial effects: in order to produce ITO, it is most important to perform chemical equilibrium in the dehydration reaction in the forward reaction direction as much as possible. In the heating process, the argon is heated, the pressure in the system is increased, and the generated water vapor also increases the pressure, so that the dehydrogenation is prevented from being carried out smoothly. Thus, when the pressure is increased to 1.5MPa, the gas is released to reduce the pressure to 1.0MPa, and the generation of the oxide is promoted by reducing the water vapor in the reaction system by the gas release. Meanwhile, because of the existence of pressure intensity, the crystal can grow slowly in the reaction kettle, and the good crystallization condition can be ensured. The invention mainly has the following characteristics:

1. the reaction condition becomes softer, ideal nanometer ITO powder can be generated under the condition of 300 ℃, and the nanometer ITO powder can be obtained by a coprecipitation method at the temperature of more than 600 ℃ basically when the ordinary ITO powder preparation process is at the temperature of more than 500 ℃. The invention solves the problem that the existing hydrothermal method preparation technology has high requirement on the temperature resistance of equipment.

2. The particle size of the particles obtained by the method is 10-20nm, and the method is more favorable for preparing the target material.

Drawings

FIG. 1 is a block flow diagram of an embodiment, which is mainly used for embodying a method for preparing nano ITO powder at a low temperature;

FIG. 2 is a schematic structural view of an embodiment, mainly used for embodying the structure of an autoclave;

FIG. 3 is a schematic structural diagram of an embodiment, which is mainly used for embodying the structure of the walking device;

FIG. 4 is a schematic structural view of the embodiment, which is mainly used for embodying a fitting structure between the walking device and the exhaust hood;

FIG. 5 is a schematic structural view of the embodiment, mainly used for embodying the structure of the exhaust hood;

fig. 6 is a schematic structural diagram of the embodiment, which is mainly used for embodying the structure of the exhaust hood.

In the figure, 1, a kettle body; 2. a cover plate; 3. discharging the air pipe; 4. an on-off valve; 5. a heat exchanger; 6. a cold fluid outlet; 7. a cold fluid inlet; 8. an exhaust pipe; 9. a walking device; 91. an exhaust funnel; 92. an exhaust hood; 93. a movable rod; 94. grid holes; 95. a spring; 96. a notch; 97. a through hole; 98. a fixed block; 10. and (7) mounting the plate.

Detailed Description

The invention is described in detail below with reference to the figures and examples.

Example 1: a method for preparing nano ITO powder at low temperature, as shown in figure 1, comprises the following steps:

s1 preparation of aqua regia solution

Preparing 80ml of aqua regia solution from concentrated hydrochloric acid and concentrated nitric acid according to the volume ratio of l: 3;

s2, dissolving and mixing

Taking 40ml of aqua regia solution, then weighing 16g of metal indium (99.99%) and 3.4g of stannic chloride to be sequentially dissolved In the aqua regia solution, and uniformly stirring for later use to obtain In₂O₃：SnO₂A mixture in a weight ratio of 9: l;

s3 coprecipitation

Adding a sodium hydroxide solution into the mixture obtained in the step S2 under stirring to make the mixture neutral, and obtaining a colloid precursor of indium hydroxide and tin hydroxide after the two are coprecipitated;

s4, filtering and washing

Washing the colloidal precursor obtained in step S3 with distilled water for 2-4 times until AgNO is used₃The colloidal precursor is detected to be Cl-free by the solution^-；

S5, reaction

Drying the indium tin hydroxide obtained in the step S4 at 100 ℃ for 4h, then placing the dried precursor into a high-pressure kettle, filling argon gas with the pressure of 0.8MPa, and then placing the high-pressure kettle on an electric furnace for heating; when the temperature rises to 250 ℃, the pressure is 1.5MPa, then the autoclave is deflated again until the pressure in the autoclave is reduced to 1.0MPa, the temperature is continuously raised to 300 ℃, the pressure in the autoclave is observed, the pressure in the autoclave is kept to be 1.0MPa by repeated deflation, and the reaction is continued for 4 hours. And (3) taking out the reaction kettle for safety, wherein the pressure in the high-pressure kettle is not more than 1.5MPa, and naturally cooling the reaction kettle to normal temperature after the reaction is finished to obtain the ITO nano-particles.

The chemical reactions that take place in the above process are as follows:

InCl₃+OH^-→In(OH)₃+Cl^-

SnCl₄+OH^-→Sn(OH)₄+Cl^-

In(OH)₃→In₂O₃+H₂O

Sn(OH)₄→SnO₂+H₂O

In₂O₃+SnO₂→ITO

in the above technical solution, it is most critical to generate ITO that the chemical equilibrium is carried out in the direction of the forward reaction as much as possible in the dehydration reaction. In the heating process, the argon is heated, the pressure in the system is increased, and the generated water vapor also increases the pressure, so that the dehydrogenation is prevented from being carried out smoothly. Thus, when the pressure is increased to 1.5MPa, the gas is released to reduce the pressure to 1.0MPa, and the generation of the oxide is promoted by reducing the water vapor in the reaction system by the gas release. Meanwhile, because of the existence of pressure intensity, the crystal can grow slowly in the reaction kettle, and the good crystallization condition can be ensured. The invention mainly has the following characteristics:

2. the reaction condition becomes softer, ideal nanometer ITO powder can be generated under the condition of 300 ℃, and the nanometer ITO powder can be obtained by a coprecipitation method at the temperature of more than 600 ℃ basically when the ordinary ITO powder preparation process is at the temperature of more than 500 ℃.

3. The particle size of the particles obtained by the method is 10-20nm, and the method is more favorable for preparing the target material.

Referring to fig. 2 to 6, the autoclave comprises a vessel body 1, a cover plate 2, a heat exchanger 5, a spreader 9 and a mounting plate 10. The cover plate 2 covers the top of the kettle body 1, an air release pipe 3 is connected between the kettle body 1 and the heat exchanger 5, and a switch valve 4 is installed on the air release pipe 3. One end of the air release pipe 3 is connected on the cover plate 2, and the other end is connected with an air inlet of the heat exchanger 5. The heat exchanger 5 is provided with a cold fluid inlet 7 for the inlet and outlet of a cold medium, a cold fluid outlet 6 and an exhaust pipe 8 for the exhaust of gas, and the cold medium is circulating cold water. The exhaust pipe 8 is used for guiding the gas after heat exchange to the high position in the room for discharging.

In the above technical solution, in step S5, the pressure in the kettle needs to be continuously reduced by the vent gas, so the on-off valve 4 needs to be opened frequently to vent the gas in the kettle to the outside through the vent pipe 8. When the traditional high-pressure autoclave is deflated, the valve is opened to directly discharge the air outwards, however, in the invention, the temperature in the autoclave body 1 is 250-300 ℃, on one hand, the direct discharge is easy to accidentally injure workers, and can cause the indoor temperature to be increased, and on the other hand, the heat loss can be caused, therefore, the heat exchanger 5 is arranged, the high-temperature gas in the autoclave body 1 firstly exchanges heat through the heat exchanger 5 and then is guided to the high altitude for discharge, so that the heat of the high-temperature gas can be effectively recovered, the potential safety hazard can be reduced, and the indoor temperature can not be influenced basically.

Referring to fig. 2 to 6, the diffuser 9 is used to disperse the gas discharged from the gas discharge pipe 8, so as to uniformly diffuse the gas around and prevent the gas from being discharged too intensively. The walking device 9 is fixed on a mounting plate 10, and the mounting plate 10 is provided with mounting holes so as to connect the mounting plate 10 on an indoor ceiling or a wall body through the mounting holes. The walking device 9 includes an exhaust funnel 91, an exhaust hood 92, a movable rod 93, a spring 95, and a fixed block 98. The exhaust funnel 91 is cylindrical, the upper end and the lower end of the exhaust funnel are both provided with openings, and the upper end of the exhaust funnel 91 is fixed on the mounting plate 10. The exhaust hood 92 is located below the exhaust funnel 91 and covers the exhaust port of the exhaust pipe 8, the exhaust hood 92 is made of soft rubber, and the exhaust hood 92 is of an inverted funnel shape and has a circular top view. The lower end surface of the exhaust pipe 91 is in contact with the top surface of the exhaust hood 92, and the center of the exhaust hood 92 is located on the axis of the exhaust pipe 91. The exhaust pipe 8 extends into the exhaust hood 92 and does not contact with the side wall of the exhaust hood 92, and the central axis of the exhaust pipe 8 and the central axis of the exhaust pipe 91 are on the same vertical line.

Referring to fig. 2-6, the fixing block 98 is disposed in the exhaust funnel 91 and fixed to the exhaust hood 92, and the exhaust hood 92 is provided with a through hole 97, and the through hole 97 penetrates through the fixing block 98 and the exhaust hood 92, so that the air enters the exhaust funnel 91 through the through hole 97. The spring 95 is located in the exhaust funnel 91, the lower end of the spring is fixed on the fixing block 98, the upper end of the spring is fixed on the mounting plate 10, and the circumferential surface of the exhaust funnel 91 is provided with a grid hole 94 for discharging gas outwards. The grid holes 94 are provided in plurality, and the grid holes 94 are uniformly distributed around the exhaust funnel 91. One end of the movable rod 93 is fixed on the fixed block 98, the other end passes through the grid hole 94, and the length direction of the grid hole 94 is consistent with the axial direction of the exhaust funnel 91, so that the movable rod 93 can move up and down in the grid hole 94. A plurality of gaps 96 are formed in the exhaust hood 92, the gaps 96 are uniformly distributed on the exhaust hood 92 by taking the center of the exhaust hood 92 as the center of a circle, the gaps 96 are fan-shaped gaps, and the included angle between the two straight lines is located around the through hole 97.

In the technical scheme, because the pressure in the kettle is high, if the pressure in the kettle is directly exhausted, high-pressure gas can be intensively sprayed to one position, so that the kettle body 1 can vibrate and bring high noise, even if the gas is cooled by circulating cold water, the temperature is still below 35 ℃, and certain potential safety hazard can be brought if the gas is intensively sprayed, therefore, the invention is provided with the step dispersing device 9, when the high-pressure gas is sprayed out through the exhaust pipe 8, the exhaust cover 92 drives the fixed block 98 and the movable rod 93 to move upwards under the action of pressure, one part of the gas discharged by the exhaust pipe 8 is diffused to the periphery of the exhaust cover 92 under the exhaust cover 92, one part of the gas is dispersed to the upper part of the exhaust cover 92 through the notch 96, the rest part of the gas enters the exhaust cylinder 91 through the notch 96 and the through hole 97, and finally is dispersed to the periphery of the exhaust cylinder 91 through the grid hole 94, so that the gas dispersing effect is good, so as to prevent the high-pressure gas from being intensively discharged. In addition, when the high-pressure gas is sprayed to the exhaust hood 92, the exhaust hood 92 pushes the spring 95 upwards, at this time, the gap 96 of the exhaust hood 92 becomes smaller gradually, the exhaust hood 92 moves slowly towards the exhaust pipe 91, and the impact force is transmitted to the spring 95 through the exhaust hood 92.

Example 2: a method for preparing nano ITO powder at low temperature, which is different from the embodiment 1, comprising the following steps:

s1 preparation of aqua regia solution

Preparing 80ml of aqua regia solution from concentrated hydrochloric acid and concentrated nitric acid according to the volume ratio of l: 3;

s2, dissolving and mixing

Taking 40ml of aqua regia solution, then weighing 10g of metal indium (99.99%) and 3g of stannic chloride to be sequentially dissolved In the aqua regia solution, and uniformly stirring for later use to obtain In₂O₃：SnO₂A mixture in a weight ratio of 8: l;

s3 coprecipitation

Adding a sodium hydroxide solution into the mixture obtained in the step S2 under stirring to make the mixture neutral, and obtaining a colloid precursor of indium hydroxide and tin hydroxide after the two are coprecipitated;

s4, filtering and washing

Washing the colloidal precursor obtained in step S3 with distilled water for 2-4 times until AgNO is used₃The colloidal precursor is detected to be Cl-free by the solution^-；

S5, reaction

Drying the indium tin hydroxide obtained in the step S4 at 100 ℃ for 4h, then placing the dried precursor into a high-pressure kettle, filling argon gas with the pressure of 0.8MPa, and then placing the high-pressure kettle on an electric furnace for heating; when the temperature rises to 250 ℃, the pressure is 1.5MPa, then the autoclave is deflated again until the pressure in the autoclave is reduced to 1.0MPa, the temperature is continuously raised to 300 ℃, the pressure in the autoclave is observed, the pressure in the autoclave is kept to be 1.0MPa by repeated deflation, and the reaction is continued for 4 hours. And (3) taking out the reaction kettle for safety, wherein the pressure in the high-pressure kettle is not more than 1.5MPa, and naturally cooling the reaction kettle to normal temperature after the reaction is finished to obtain the ITO nano-particles.

Example 3: a method for preparing nano ITO powder at low temperature, which is different from the embodiment 1, comprising the following steps:

s1 preparation of aqua regia solution

Preparing 80ml of aqua regia solution from concentrated hydrochloric acid and concentrated nitric acid according to the volume ratio of l: 3;

s2, dissolving and mixing

Taking 40ml of aqua regia solution, then weighing 10g of metal indium (99.99%) and 3g of stannic chloride to be sequentially dissolved In the aqua regia solution, and uniformly stirring for later use to obtain In₂O₃：SnO₂A mixture in a weight ratio of 8: l;

s3 coprecipitation

Adding a sodium hydroxide solution into the mixture obtained in the step S2 under stirring to make the mixture neutral, and obtaining a colloid precursor of indium hydroxide and tin hydroxide after the two are coprecipitated;

s4, filtering and washing

With distilled waterWashing the colloidal precursor obtained in step S3 for 2-4 times until AgNO is used₃The colloidal precursor is detected to be Cl-free by the solution^-；

S5, reaction

Drying the indium tin hydroxide obtained in the step S4 at 100 ℃ for 4h, then placing the dried precursor into a high-pressure kettle, filling argon gas with the pressure of 0.8MPa, and then placing the high-pressure kettle on an electric furnace for heating; when the temperature rises to 250 ℃, the pressure is 1.5MPa, then the autoclave is deflated again until the pressure in the autoclave is reduced to 1.0MPa, the temperature is continuously raised to 300 ℃, the pressure in the autoclave is observed, the pressure in the autoclave is kept to be 1.0MPa by repeated deflation, and the reaction is continued for 4 hours. And (3) taking out the reaction kettle for safety, wherein the pressure in the high-pressure kettle is not more than 1.5MPa, and naturally cooling the reaction kettle to normal temperature after the reaction is finished to obtain the ITO nano-particles.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that several improvements and modifications without departing from the principle of the present invention will occur to those skilled in the art, and such improvements and modifications should also be construed as within the scope of the present invention.