CN1269739C - Method for preparing pale-antimony mixed nano tin-oxide powder - Google Patents

Abstract

The invention provides a method for preparing light-colored antimony-doped nano tin oxide powder. Including the preparation of acidic mixed solution, ammonia water neutralization precipitation reaction and precipitate washing, drying, sieving and calcining process, it is characterized in that: (1) acidic mixed solution is added dropwise to tin powder, antimony trioxide , the concentration of nitric acid is 1-12mol/L, the concentration of tin in the acidic mixed solution is 0.2-2mol/L, and the ratio of the amount of antimony/tin is 1:100-15:100; (2) the acidic mixed solution And ammonia water is added dropwise to distilled water in the way of co-current dropwise addition, and the pH value is controlled to obtain a precipitate. Finally, it is calcined at 400-900°C for 2-4 hours to obtain a light-colored nano-tin oxide conductive powder with good dispersion, less agglomeration and an average grain size of about 15nm. The resistivity of the antimony-doped nano tin oxide powder is lower than 10 ^-2 Ωcm. The method has the characteristics of simple process, low production cost, large-scale production and the like.

Description

Preparation method of light-colored antimony-doped nano tin oxide powder

technical field

The invention relates to a preparation method of light-colored nano-tin oxide conductive powder, which can be used for antistatic materials, three-proof materials for picture tubes, electrode materials and solar energy conversion devices. It belongs to the field of nanomaterials.

Background technique

Antimony-doped tin oxide, referred to as ATO, is a widely used functional material, widely used in solar energy conversion devices, transparent electrodes, gas-sensitive materials, conductive coatings, smart windows, antistatic materials, and catalytic materials. In recent years, due to the rapid development of nanotechnology, especially nanomaterials, the research on nano-ATO powder has also become a research hotspot.

Nano-tin oxide refers to tin oxide products with a grain size of less than 100nm. Using it to replace micron-sized tin oxide can greatly reduce the amount of tin oxide powder, improve the electrical and optical properties of the powder, catalytic performance, and gas-sensitive materials. Responsiveness. Therefore, nano tin oxide conductive powder has great practical value. The preparation method of ATO mainly contains mechanical mixing method (MKParia et al., J.Mater.Sci., 1982vol.17, p3275-3280), coprecipitation method (J.Rockenberger et al., J.Chem.Phys., 2000, vol .112(9), p4292-4304; Jean C.Robert et al., US Patent5401441 1995), hydrothermal method (C.Goebbert et al., Thin SolidFilms, 1999, vol.351, p79-84), but these Both methods have some shortcomings. The mechanical mixing method is to mechanically mix tin oxide and antimony trioxide and then calcined to obtain conductive powder. Its advantage is that the process is simple and the production cost is low. Its disadvantage is that the particle size of the powder is large and the distribution is wide, the doping is very uneven, and it cannot meet the high application requirements. Now this method has been eliminated. Co-precipitation methods use SnCl ₄ , SbCl ₃ , and HCl as raw materials to form an acidic solution, add a precipitant to produce precipitation, and then wash with distilled water to remove Cl ^- , because the presence of Cl ^- seriously affects the conductivity of the powder, and It will also have a serious corrosion effect on other materials. In addition, the Cl ^- on the surface of the hydrated tin oxide is extremely difficult to remove, so a large amount of distilled water is required for washing, which makes the production cycle longer and the production cost higher. The raw materials of the hydrothermal method are also SnCl ₄ and SbCl ₃ , and due to the expensive equipment and large investment of the hydrothermal method, it is not easy to industrialize.

Therefore, the production of ATO nano conductive powder still has the problems of excessive distilled water consumption, long production cycle and high cost in the production process.

Contents of the invention

The purpose of the present invention is to provide a method for preparing light-colored nano tin oxide conductive powder. The powder obtained by the method has the characteristics of small grain size, less agglomeration and good electrical conductivity, and is suitable for industrial production.

The object of the present invention is implemented like this: take tin powder, antimony trioxide, nitric acid as raw material to be mixed with acidic mixed solution, then carry out precipitation reaction with ammonia water as precipitating agent, precipitate is washed, dried to make hydrated oxide powder Body, after calcining to obtain light-colored nano tin oxide conductive powder. Its reaction condition is:

a. Preparation conditions of acidic mixed solution:

The concentration of nitric acid is 1-12mol·L ^-1 , the concentration of tin in the acidic mixed solution is 0.2-2mol·L ^-1 , the ratio of antimony:tin is 1:100-15:100, and the preparation temperature is 0 -80°C.

b. Precipitation reaction conditions:

The concentration of ammonia water is 1-12mol·L ^-1 , the temperature of the precipitation reaction is 0-80°C, the reaction pH value is 2-10, and the reaction time is 1-2 hours.

c. Precipitation drying conditions:

The drying temperature is 100° C., and the drying time is 2 hours.

d. Precursor calcination conditions:

The calcination temperature is 400-900°C; the calcination time is 2-4 hours.

The process steps are:

a. Carefully add a certain concentration of nitric acid solution dropwise to tin powder and antimony trioxide under vigorous stirring to prepare a clear and transparent light-colored acidic mixed solution. (the preparation of acidic mixed solution is a key step in the preparation method provided by the invention)

b. Prepare a certain concentration of ammonia solution.

c. Under vigorous stirring, the acidic mixed solution and ammonia water of a certain concentration are added dropwise to distilled water at a certain temperature in the manner of co-current dropwise addition, and a certain pH value is controlled to obtain a precipitate.

d. Wash the precipitate twice with distilled water and then twice with absolute ethanol.

e. Dry the precipitate at 100°C for 2 hours, grind it, and pass it through a 200-mesh sieve.

f. Calcining the sieved precursor precipitate at 400-900° C. for 2-4 hours.

The characteristics of the preparation method of the light-colored nano tin oxide conductive powder provided by the invention are:

a. The prepared nano-tin oxide conductive powder has a small grain size, only about 15nm, and less agglomeration.

b. The preparation process is simple, the requirements for equipment are not high, and the industrial production is easy.

c. Using tin powder, antimony trioxide and nitric acid as raw materials, since the nitrate can be completely decomposed during the calcination process, the problem of Cl ^- removal is fundamentally eliminated, thereby greatly reducing the production cost and shortening the production cycle .

Description of drawings

Fig. 1 is the X-ray diffraction pattern of the tin oxide conductive powder obtained by doping with 5% and calcined at 600° C. for 3 hours.

Fig. 2 is a transmission electron micrograph of tin oxide conductive powder obtained by doping with 5% and calcined at 600°C for 3 hours.

Figure 3 is the X-ray diffraction pattern of tin oxide conductive powder obtained by doping with 5% and calcined at 800°C for 2 hours.

Fig. 4 is an X-ray diffraction pattern of the tin oxide conductive powder obtained by doping with 3% and calcined at 400° C. for 3 hours.

Figure 5 is a transmission electron micrograph of the tin oxide conductive powder obtained by doping with 9% and calcined at 700°C for 3 hours.

Detailed ways

Example 1

Accurately weigh 5.93g of Sn powder, 0.39g of Sb ₂ O ₃ powder (the doping ratio is Sn: Sb material ratio is 5%) and put them in a round bottom flask. The round bottom flask is kept at 50°C. ^-1 HNO ₃ was added dropwise to the flask under vigorous stirring until a clear, transparent, light-colored acidic mixed solution was formed in the flask. Add this acidic mixed solution and 6mol·L ^-1 ammonia solution dropwise into a vigorously stirred round-bottomed flask in parallel flow, control the pH value of the reaction to 7, control the reaction temperature to 30°C, and react for 1 hour to obtain precipitation. The precipitate was filtered, washed with distilled water, and suction filtered to remove impurity ions. This washing process was repeated twice, and then washed twice with absolute ethanol. The precipitate was dried at 100°C for 2 hours, ground, and passed through a 200-mesh sieve. The precursor precipitate was calcined at 600°C for 3 hours, and then cooled to room temperature naturally to obtain blue tin oxide powder. Figure 1 is the X-ray diffraction diagram of the powder. The results show that tin oxide has a tetragonal rutile structure, and the diffraction peaks are obviously broadened. The grain size calculated by the Scherrer formula for the (100) crystal plane of the powder is 16nm. Figure 2 is a transmission electron microscope photo of the powder, the particle size of the powder is about 15nm, which is consistent with the results obtained by XRD. The powder has better dispersibility and less agglomeration.

Accurately weigh 1.00g of the above-mentioned conductive powder, place it in a cylindrical mold with a diameter of 20.0mm, and apply a pressure of 4T (ton) per square centimeter to obtain a disc-shaped block, and measure its density with four probes. The resistivity is 0.36Ωcm.

Example 2

Accurately weigh 5.93g of Sn powder, 0.39g of Sb ₂ O ₃ powder (the doping ratio is Sn: Sb material ratio is 5%) and put them in a round bottom flask. ^-1 HNO ₃ was added dropwise to the flask under vigorous stirring until a clear, transparent, light-colored acidic mixed solution was formed in the flask. Add this acidic mixed solution and 8 mol·L ^-1 ammonia solution into a vigorously stirred round-bottomed flask in parallel flow, control the pH value of the reaction to 4, control the reaction temperature to 60°C, and react for 1 hour to obtain precipitation. The precipitate was filtered, washed with distilled water, and suction filtered to remove impurity ions. This washing process was repeated twice, and then washed twice with absolute ethanol. The precipitate was dried at 100°C for 2 hours, ground, and passed through a 200-mesh sieve. Then calcined at 800°C for 2 hours, and cooled naturally to room temperature to obtain blue tin oxide powder. Figure 3 is the X-ray diffraction pattern of the powder, the results show that tin oxide has a tetragonal rutile structure, and the grain size is 23nm calculated from the (100) crystal plane of the powder by the Scherrer formula.

Accurately weigh 1.00g of conductive powder, place it in a cylindrical mold with a diameter of 20.0mm, apply a pressure of 4T (ton) per square centimeter, and make a disc-shaped block, and measure its resistivity with four probes is 0.9Ωcm.

Example 3

Accurately weigh 5.90 g of Sn powder, 0.22 g of Sb ₂ O ₃ powder (the doping ratio is Sn: Sb material ratio is 3%) and place them in a round bottom flask. The temperature of the round bottom flask is kept at 40° C. ^-1 HNO ₃ was added dropwise to the flask under vigorous stirring until a clear, transparent, light-colored acidic mixed solution was formed in the flask. Add this acidic mixed solution and 12mol·L ^-1 ammonia solution into a vigorously stirred round-bottomed flask in parallel flow, control the pH value of the reaction to 10, control the reaction temperature to 80°C, and react for 2 hours to obtain precipitation. The precipitate was filtered, washed with distilled water, and suction filtered to remove impurity ions. This washing process was repeated twice, and then washed twice with absolute ethanol. The precipitate was dried at 100°C for 2 hours, ground, and passed through a 200-mesh sieve. Then calcined at 400°C for 3 hours, and cooled naturally to room temperature to obtain blue tin oxide powder. Figure 4 is the X-ray diffraction pattern of the powder. The results show that the tin oxide has a tetragonal rutile structure, and the diffraction peak broadens significantly. The grain size calculated by the Scherrer formula for the (100) crystal plane of the powder is 10nm.

Accurately weigh 1.00g of conductive powder, place it in a cylindrical mold with a diameter of 20.0mm, apply a pressure of 4T (ton) per square centimeter, and make a disc-shaped block, and measure its resistance with four probes The ratio is 8Ωcm.

Example 4

Accurately weigh 7.2g of Sn powder, 0.8g of Sb ₂ O ₃ powder (the doping ratio is Sn:Sb material ratio is 9%) and put them in a round bottom flask, the temperature of the round bottom flask is kept at 80°C, and 5mo·1L ^-1 HNO ₃ was added dropwise to the flask under vigorous stirring until a clear, transparent, light-colored acidic mixed solution was formed in the flask. Add this acidic mixed solution and 6 mol·L ^-1 ammonia solution dropwise into a vigorously stirred round-bottom flask in parallel flow, control the pH value of the reaction to 7, control the reaction temperature to 20°C, and react for 1 hour to obtain precipitation. The precipitate was filtered, washed with distilled water, and suction filtered to remove impurity ions. This washing process was repeated twice, and then washed twice with absolute ethanol. The precipitate was dried at 100°C for 2 hours, ground, and passed through a 200-mesh sieve. Then calcined at 700°C for 3 hours, and cooled naturally to room temperature to obtain blue tin oxide powder. Figure 5 is a transmission electron microscope photo of the powder, the particle size of the powder is about 17nm, and the agglomeration is less.

Accurately weigh 1.00g of conductive powder, place it in a cylindrical mold with a diameter of 20.0mm, apply a pressure of 4T (ton) per square centimeter, and make a disc-shaped block, and measure its resistance with four probes The ratio is 0.7Ωcm.

Claims (3)

1. A method for preparing antimony-doped nano-tin oxide powder, comprising preparation of an acidic mixed solution, neutralization precipitation reaction in ammonia water, and sediment washing, drying, sieving and calcination processes, characterized in that: (1) The acidic mixed solution is to add nitric acid solution dropwise to tin powder and antimony trioxide, the concentration of nitric acid is 1-12mol/L, the concentration of tin in the acidic mixed solution is 0.2-2mol/L, the antimony/tin The ratio of the amount of substances is 1:100-15:100, and the preparation temperature is 0-80°C; (2) The acidic mixed solution and ammonia water are added dropwise to distilled water in the manner of co-current dropwise addition, and the pH value is controlled to obtain a precipitate; the concentration of the described ammonia solution is 1-12mol/L; the co-current dropwise addition The reaction temperature is 0-80°C, the reaction pH value is 2-10, and the reaction time is 1-2 hours; (3) The precipitate is washed, dried and sieved and calcined at 400-900°C for 2-4 hours; after washing, the precipitate is dried at 100°C for 2 hours. 2. The method for preparing antimony-doped nano-tin oxide powder according to claim 1, characterized in that the precipitate is first washed with distilled water and then washed with absolute ethanol. 3. The method for preparing antimony-doped nano tin oxide powder according to claim 1, characterized in that the precipitate is passed through a 200-mesh sieve after drying.

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