CN114604889A - A kind of preparation method of copper-based oxide La2CuO4 powder material - Google Patents

Abstract

The invention discloses a preparation method of a copper-based oxide _La2CuO4 powder material. The method comprises the following steps: mixing lanthanum _{oxide La2O3} and copper oxide _CuO and placing them in a ball mill; vacuumizing the ball mill to make the vacuum If the temperature is less than 6Pa, then fill the ball mill tank with argon, repeat the above steps at least three times and then dry grinding; after the dry grinding, inject argon and anhydrous ethanol into the air inlet and outlet of the ball mill tank respectively, At the end, close the air outlet and the air inlet in turn, and perform wet grinding; the nano powder obtained by drying the wet-milled mixture is placed in a mold, and pressed into a sheet-like sample by an electric powder tableting machine, and placed in a crucible; The crucible is placed in a resistance furnace for heating and heat preservation, and then cooled to room temperature with the resistance furnace; the flake samples in the crucible are taken out for grinding and sieving to obtain nano-powders of copper-based oxides. The present invention realizes La ₂ CuO ₄ The simple preparation of powder, low cost, short time and controllable particle size, can be used for large-scale industrial production.

Description

A kind of preparation method of copper-based oxide La2CuO4 powder material

technical field

The invention relates to the technical field of copper-based oxides, in particular to a preparation method of a copper-based oxide La ₂ CuO ₄ powder material.

Background technique

The copper-based oxide La ₂ CuO ₄ is a layered perovskite-like (La ₂ CuO 3 ) formed by overlapping a perovskite layer (LaCuO ₃ ) and a salt rock layer (LaO) in a ratio of 1:1 along the c-axis direction. ₄ ) Composite oxides. In this layered structure, the interface between LaO layer and LaCuO ₃ layer has a strong scattering effect on phonons, so La ₂ CuO ₄ has low thermal conductivity, and the composite oxide of this structure is easy to form an oxygen-deficient type The non-stoichiometric compounds have good oxygen exchange and diffusion capacity, so they can be used as a new type of oxygen-sensitive material with development prospects. In recent years, it has been found that La ₂ CuO ₄ has a large Seebeck coefficient. According to literature records, its Seebeck coefficient at room temperature can reach 340uV/K. By optimizing electrical properties and reducing thermal conductivity, it can be A good ZT value is obtained in the system, which becomes a potential thermoelectric material. In addition, La ₂ CuO ₄ also has good application potential in catalytic oxidation of organic matter, catalytic purification of automobile exhaust and catalytic elimination of nitrogen oxides.

During the preparation of this perovskite-type composite oxide, different preparation methods have a great influence on the physical and chemical properties of the samples, such as structure, morphology, particle size, specific surface area and even the catalytic activity of the reaction. For example, solid-state reaction method, self-propagating combustion method, sol-gel method, etc. Most of the above-mentioned chemical methods are used to synthesize nanomaterials by sol-gel method, which has small yield and long time. When the metal ions cannot be completely complexed, the polymerization reaction cannot be carried out. The practical application of this process is limited.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of a copper-based oxide La ₂ CuO ₄ powder material.

The technical solution for realizing the object of the present invention is: a preparation method of a copper-based oxide La ₂ CuO ₄ powder material, comprising the following steps:

1) adopt lanthanum oxide La ₂ O ₃ and copper oxide CuO to carry out batching mixing and put into ball mill tank;

2) carry out vacuum treatment to the ball mill jar, so that the vacuum degree is less than 6Pa, then fill the ball mill jar with argon, repeat the above steps at least three times and then carry out dry grinding;

3) After the dry grinding, inject argon and dehydrated alcohol into the air inlet and the air outlet of the ball mill jar simultaneously, close the air outlet and the air inlet after the injection, and perform wet grinding;

4) The nanopowder obtained by drying the wet-milled mixture is placed in a mold, compressed into a sheet-like sample by an electric powder press, and placed in a crucible with 99% alumina;

5) Put the crucible into the resistance furnace for heating and heat preservation, and then cool down to room temperature with the resistance furnace;

6) Take out the flake sample in the crucible for grinding and sieving to obtain nano-powder of copper-based oxide.

Further, the rotational speed of the dry grinding is 100-500rpm, and the time is 15min-96h.

Further, the rotational speed of the wet grinding is 50-300 rpm, and the time is 15 min-12 h.

Further, the drying temperature is 20-200° C., and the time is 4-20 h.

Further, the pressure of the electric powder tablet press is 10-50MPa;

Further, the diameter of the sheet-like sample is 12.5 mm, and the height is a cylindrical sheet body of 3-15 mm.

Further, for heating and heat preservation in the resistance furnace, the temperature is first heated to 750 to 900°C at a rate of 50 to 150°C/h, and then heated to 800 to 950°C at a rate of 20 to 50°C/h, and kept for 5 to 50°C. 24h.

Compared with the prior art, the beneficial effects of the present invention:

The present invention realizes simple preparation of La ₂ CuO ₄ powder, low cost, short time, controllable particle size (adjusting ball milling speed, ball milling time and sieve aperture), and can be used for large-scale industrial production.

Description of drawings

Fig. 1 is the X-ray diffraction (XRD) pattern of the copper-based oxide powder prepared in Examples 3, 4 and 5 of the present invention;

Fig. 2 is the transmission electron microscope (TEM) figure of the copper-based oxide powder material of the present invention;

3 is an enlarged view of a transmission electron microscope (TEM) of the copper-based oxide powder material of the present invention.

Detailed ways

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

La ₂ O ₃ :CuO=1:1 used in the following examples is a conventional stoichiometric ratio, and a single La ₂ CuO ₄ phase can be synthesized according to this ratio.

Example 1

A preparation method of a copper-based oxide La ₂ CuO ₄ powder material, comprising:

Step 1. Use high-purity La ₂ O ₃ and CuO oxides as initial raw materials, and mix them into powder according to the ratio of La ₂ O ₃ :CuO=1:1;

Step 2. Put the mixed powder into the ball mill tank. In order to prevent the powder from deteriorating in the air, vacuum the ball mill tank filled with the powder so that the vacuum degree is less than 6Pa. After the vacuum is exhausted, the ball mill tank is filled with argon gas. , in order to remove the air in the tank, the above vacuum treatment, inflating argon process is cycled for more than three times, the rotation speed of the control ball mill tank is 100rpm, the time is 15min, and dry grinding is performed;

During the dry grinding operation, the mutual grinding effect between the powder particles is large, which is conducive to the roundness of the particle shape, and the compact density is also higher;

Step 3. In order to prevent the powder from agglomerating and make the ball milling more uniform, after the dry grinding, inject argon into the air inlet of the ball mill, and inject anhydrous ethanol into the air outlet of the ball mill. After ethanol, close the air outlet first and then the air inlet; control the rotational speed of the ball mill tank to be 50rpm and the time to be 15min, and perform wet grinding;

In the process of wet grinding, anhydrous ethanol is added to limit the agglomeration of the powder and promote particle refinement, so the refining efficiency of wet grinding is higher. The dry grinding and wet grinding are combined, and the time of dry grinding and wet grinding is adjusted. The rotation speed can get the desired particle size;

Step 4: drying the wet-milled mixture at a drying temperature of 20° C. and a time of 4 hours, finally obtaining a nano-powder in which La ₂ O ₃ and CuO are fully mixed and uniform;

Step 5. Put the nano powder into a mold with a diameter of 12.5mm, press it into a cylindrical sheet with a diameter of 12.5mm and a height of 15mm under the pressure of 10MPa of an electric powder tablet press, and evenly put it into a 99% oxidized tablet. In the aluminum crucible, cover the crucible cover;

Step 6. Put the crucible containing the sheet sample into the box-type resistance furnace evenly. The temperature control program of the box-type resistance furnace is: firstly raise the temperature to 750°C at a rate of 50°C/h, and then increase the temperature to 750°C at a rate of 20°C/h. The temperature was raised to 800°C at a rate of h, kept for 5h, and then cooled to room temperature with the furnace;

Step 6: Take out the flake sample obtained after the solid-state reaction in Step 5 from the crucible, grind it into powder with a mortar, and then sieve it with a 200-mesh sieve to finally obtain La ₂ CuO ₄ nano-powder.

Example 2

A preparation method of a copper-based oxide La ₂ CuO ₄ powder material, comprising:

Step 1. Use high-purity La ₂ O ₃ and CuO oxides as initial raw materials, and mix them into powder according to the ratio of La ₂ O ₃ :CuO=1:1;

Step 2. Put the mixed powder into the ball mill tank. In order to prevent the powder from oxidizing and changing the price, vacuum treatment is performed on the ball mill tank filled with the powder, so that the vacuum degree is less than 6Pa. After vacuuming, the ball mill tank is filled with argon, in order to eliminate For the air in the tank body, the above vacuum treatment and argon gas filling process are cycled for more than three times, and the rotation speed of the ball mill tank is controlled to be 500rpm and the time is 96h, and dry grinding is performed;

Step 3. In order to prevent the powder from agglomerating and make the ball milling more uniform, after the dry grinding, inject argon into the air inlet of the ball mill, and inject anhydrous ethanol into the air outlet of the ball mill. After ethanol, first close the air outlet and then close the air inlet; control the speed of the ball mill to 300rpm and the time to 12h, and perform wet grinding;

Step 4, drying the wet-milled mixture at a drying temperature of 200° C. and a time of 20 hours, finally obtaining a nano-powder in which La ₂ O ₃ and CuO are fully mixed and uniform;

Step 5. Put the nano powder into a mold with a diameter of 12.5mm, press it into a cylindrical sheet with a diameter of 12.5mm and a height of 3mm under the pressure of 50MPa by an electric powder tablet press, and evenly put it into 99% oxidized In the aluminum crucible, cover the crucible cover;

Step 6. Put the crucible containing the sheet samples into the box-type resistance furnace evenly. The temperature control program of the box-type resistance furnace is: firstly raise the temperature to 900°C at a rate of 150°C/h, and then increase the temperature at 50°C/h. The temperature was raised to 950°C at a rate of h, kept for 24h, and then cooled to room temperature with the furnace;

Step 6: Take out the flake sample obtained after the solid-state reaction in Step 5, grind it into powder with a mortar, and then sieve it with a 500-mesh sieve to finally obtain La ₂ CuO ₄ nano-powder.

Example 3

A preparation method of a copper-based oxide La ₂ CuO ₄ powder material, comprising:

Step 1. Use high-purity La ₂ O ₃ and CuO oxides as initial raw materials, and mix them into powder according to the ratio of La ₂ O ₃ :CuO=1:1;

Step 2. Put the mixed powder into the ball mill tank. In order to prevent the powder from oxidizing and changing the price, vacuum treatment is performed on the ball mill tank filled with the powder, so that the vacuum degree is less than 6Pa. After vacuuming, the ball mill tank is filled with argon, in order to eliminate For the air in the tank body, the above vacuum treatment and argon gas filling process are cycled for more than three times, and the rotation speed of the ball mill tank is controlled to be 300rpm and the time is 300min, and dry grinding is performed;

Step 3. In order to prevent the powder from agglomerating and make the ball milling more uniform, after the dry grinding, inject argon into the air inlet of the ball mill, and inject anhydrous ethanol into the air outlet of the ball mill. After ethanol, close the air outlet first and then close the air inlet; control the rotational speed of the ball mill jar to 300rpm and the time to 300min to perform wet grinding;

Step 4: drying the wet-milled mixture, the drying temperature is 50°C, and the drying time is 10h, and finally a nano-powder in which La ₂ O ₃ and CuO are fully mixed and uniform is obtained;

Step 5. Put the nano powder into a mold with a diameter of 12.5mm, press it into a cylindrical sheet with a diameter of 12.5mm and a height of 3mm under the pressure of 50MPa by an electric powder tablet press, and evenly put it into 99% oxidized In the aluminum crucible, cover the crucible cover;

Step 6. Put the crucible containing the sheet sample into the box-type resistance furnace evenly. The temperature control program of the box-type resistance furnace is: firstly raise the temperature to 800°C at a rate of 100°C/h, and then increase the temperature at a rate of 20°C/h. The temperature was raised to 850 °C at a rate of h, kept for 12 h, and then cooled to room temperature with the furnace;

Step 6: Take out the flake sample obtained after the solid-state reaction in Step 5 from the crucible, grind it into powder with a mortar, and then sieve it with a 200-mesh sieve to finally obtain La ₂ CuO ₄ nano-powder.

Example 4

A preparation method of a copper-based oxide La ₂ CuO ₄ powder material, comprising:

Step 1. Use high-purity La ₂ O ₃ and CuO oxides as initial raw materials, and mix them into powder according to the ratio of La ₂ O ₃ :CuO=1:1;

Step 2. Put the mixed powder into the ball mill tank. In order to prevent the powder from oxidizing and changing the price, vacuum treatment is performed on the ball mill tank filled with the powder, so that the vacuum degree is less than 6Pa. After vacuuming, the ball mill tank is filled with argon, in order to eliminate For the air in the tank body, the above vacuum treatment and argon gas filling process are cycled for more than three times, and the rotation speed of the ball mill tank is controlled to be 300rpm and the time is 300min, and dry grinding is performed;

Step 3. In order to prevent the powder from agglomerating and make the ball milling more uniform, after the dry grinding, inject argon into the air inlet of the ball mill, and inject anhydrous ethanol into the air outlet of the ball mill. After ethanol, close the air outlet first and then close the air inlet; control the rotational speed of the ball mill jar to 300rpm and the time to 300min to perform wet grinding;

Step 4: drying the wet-milled mixture, the drying temperature is 50°C, and the drying time is 10h, and finally a nano-powder in which La ₂ O ₃ and CuO are fully mixed and uniform is obtained;

Step 5. Put the nano powder into a mold with a diameter of 12.5mm, press it into a cylindrical sheet with a diameter of 12.5mm and a height of 3mm under the pressure of 50MPa by an electric powder tablet press, and evenly put it into 99% oxidized In the aluminum crucible, cover the crucible cover;

Step 6. Put the crucible containing the sheet sample into the box-type resistance furnace evenly. The temperature control program of the box-type resistance furnace is: firstly raise the temperature to 850°C at a rate of 100°C/h, and then increase the temperature at a rate of 20°C/h. The temperature was raised to 900 °C at a rate of h, kept for 12 h, and then cooled to room temperature with the furnace;

Step 6: Take out the flake sample obtained after the solid-state reaction in Step 5 from the crucible, grind it into powder with a mortar, and then sieve it with a 200-mesh sieve to finally obtain La ₂ CuO ₄ nano-powder.

Example 5

A preparation method of a copper-based oxide La ₂ CuO ₄ powder material, comprising:

Step 1. Use high-purity La ₂ O ₃ and CuO oxides as initial raw materials, and mix them into powder according to the ratio of La ₂ O ₃ :CuO=1:1;

Step 2. Put the mixed powder into the ball mill tank. In order to prevent the powder from oxidizing and changing the price, vacuum treatment is performed on the ball mill tank filled with the powder, so that the vacuum degree is less than 6Pa. After vacuuming, the ball mill tank is filled with argon, in order to eliminate For the air in the tank body, the above vacuum treatment and argon gas filling process are cycled for more than three times, and the rotation speed of the ball mill tank is controlled to be 300rpm and the time is 300min, and dry grinding is performed;

Step 3. In order to prevent the powder from agglomerating and make the ball milling more uniform, after the dry grinding, inject argon into the air inlet of the ball mill, and inject anhydrous ethanol into the air outlet of the ball mill. After ethanol, close the air outlet first and then close the air inlet; control the rotational speed of the ball mill jar to 300rpm and the time to 300min to perform wet grinding;

Step 4: drying the wet-milled mixture, the drying temperature is 50°C, and the drying time is 10h, and finally a nano-powder in which La ₂ O ₃ and CuO are fully mixed and uniform is obtained;

Step 5. Put the nano powder into a mold with a diameter of 12.5mm, press it into a cylindrical sheet with a diameter of 12.5mm and a height of 3mm under the pressure of 50MPa by an electric powder tablet press, and evenly put it into 99% oxidized In the aluminum crucible, cover the crucible cover;

Step 6. Put the crucible containing the sheet sample into the box-type resistance furnace evenly. The temperature control program of the box-type resistance furnace is: firstly raise the temperature to 900°C at a rate of 100°C/h, and then increase the temperature to 900°C at a rate of 20°C/h. The temperature was raised to 950 °C at a rate of h, kept for 12 h, and then cooled to room temperature with the furnace;

Step 6. Take out the flake sample obtained after the solid-state reaction in Step 5, grind it into powder with a mortar, and then sieve it with a -200 mesh sieve to finally obtain La ₂ CuO ₄ nano-powder.

In Figure 1, a, b, and c are the X-ray diffraction (XRD) patterns of the copper-based oxide powders prepared in Examples 3, 4, and 5, respectively. It can be seen from Figure 1 that all the characteristic peaks of the powder are La ₂ CuO ₄ characteristic line (PDF#38-0709).

The above examples are only to describe the present invention in detail, but the protection scope of the present invention is not limited to this. Any person familiar with the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, all should be covered in this invention. within the scope of protection of the invention.

Claims (7)

1. a preparation method of copper-based oxide La ₂ CuO ₄ powder material, is characterized in that, comprises the steps: 1) adopt lanthanum oxide La ₂ O ₃ and copper oxide CuO to carry out batching mixing and put into ball mill tank; 2) carry out vacuum treatment to the ball mill jar, so that the vacuum degree is less than 6Pa, then fill the ball mill jar with argon, repeat the above steps at least three times and then carry out dry grinding; 3) After the dry grinding, inject argon and dehydrated alcohol into the air inlet and the air outlet of the ball mill jar simultaneously, close the air outlet and the air inlet after the injection, and perform wet grinding; 4) The nanopowder obtained by drying the wet-milled mixture is placed in a mold, compressed into a sheet-like sample by an electric powder press, and placed in a crucible with 99% alumina; 5) Put the crucible into the resistance furnace for heating and heat preservation, and then cool down to room temperature with the resistance furnace; 6) Take out the flake sample in the crucible for grinding and sieving to obtain nano-powder of copper-based oxide. 2 . The preparation method of the copper-based oxide La ₂ CuO ₄ powder material according to claim 1 , wherein the dry grinding speed is 100-500 rpm, and the time is 15 min-96 h. 3 . 3 . The method for preparing copper-based oxide La ₂ CuO ₄ powder material according to claim 1 , wherein the rotational speed of the wet grinding is 50-300 rpm, and the time is 15 min-12 h. 4 . 4 . The preparation method of the copper-based oxide La ₂ CuO ₄ powder material according to claim 1 , wherein the drying temperature is 20-200° C. and the time is 4-20 h. 5 . 5 . The method for preparing copper-based oxide La ₂ CuO ₄ powder material according to claim 1 , wherein the pressure of the electric powder tableting machine is 10-50 MPa. 6 . 6 . The method for preparing copper-based oxide La ₂ CuO ₄ powder material according to claim 1 , wherein the sheet-like sample has a diameter of 12.5 mm and a cylindrical sheet with a height of 3-15 mm. 7 . 7 . The preparation method of the copper-based oxide La ₂ CuO ₄ powder material according to claim 1 , wherein the heating and heat preservation in the resistance furnace are first heated at a rate of 50-150° C./h to a temperature of 50-150° C./h. 750～900℃, then raise the temperature to 800～950℃ at a rate of 20～50℃/h, and keep the temperature for 5～24h.

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