CN114368773B - Method for preparing cerium oxide nano particles by two-step method - Google Patents

Abstract

The invention discloses a method for preparing cerium dioxide nano particles by a two-step method, which adopts a strategy of precipitation and oxidation, and comprises the following specific steps: at normal temperature, willWeighed Ce (NO) ₃ ) ₃ ·6H ₂ O and NaOH are respectively dissolved in water; mixing the two solutions, and stirring for 15 min; then the obtained precipitate is centrifugally washed and then is dried in a vacuum drying oven at 60 ℃; exposing the dried sample to air to slowly oxidize the surface of the sample; then dispersing in water, adding hydrogen peroxide solution, and carrying out water bath 2h at 40 ℃ to obtain the cerium oxide nano particles. The cerium oxide nano particles obtained under the conditions of no surfactant and no need of high-temperature calcination have primary particle sizes within 5-15 nm and secondary particle sizes within 120-460 nm, and the preparation method is simple in synthesis process, environment-friendly, low in preparation raw material cost, low in equipment requirement, high in production efficiency, good in reproducibility and easy for industrial production.

Description

A kind of method that prepares ceria nanoparticle with two-step method

technical field

The invention relates to a synthesis method of rare earth materials, in particular to a synthesis of ceria nanoparticles.

Background technique

Ceria is an inexpensive and versatile light rare earth material. Mainly used in polishing materials, luminescent materials, ultraviolet absorbers, functional ceramic materials, glass decolorizers, automobile exhaust purification, catalyst carriers, etc.

At present, the methods for synthesizing ceria nanoparticles include: spray pyrolysis method, microemulsion method, hydrothermal method, precipitation method, sol-gel method, etc. The spray pyrolysis method requires high equipment. The microemulsion method has the disadvantages of high raw material cost, complicated process, and environmental pollution. The precursors obtained by the hydrothermal method and precipitation method generally need to be calcined at high temperature, which is easy to agglomerate and consumes high energy. So that it is limited in industrial production and application.

The preparation idea of the above-mentioned traditional method can generally be divided into the following two steps: the first step is to use a precipitating agent or a complexing agent to react with a cerium salt to obtain cerium hydroxide or a complex of cerium as a precursor of cerium oxide; In the second step, the precursor is converted into ceria nanomaterials by high-temperature calcination, condensation and reflux.

The Chinese patent application with the publication number CN107381616A discloses a method for preparing cerium dioxide nanoparticles with organic templates, using cerium nitrate as the source of cerium, and using 2-methylimidazole as the template material. The molar ratio is 67.1:55 to configure the solution, mix and stir at room temperature, centrifuge, wash and dry, put the above complex in a muffle furnace, and calcinate at 300-400°C for 3 hours to obtain nano-ceria.

The Chinese patent application with the publication number CN110577233A discloses a method for preparing cerium dioxide nanoparticles by high-temperature calcination, using cerium nitrate and dimethyl oxalate as the cerium source and complexing agent respectively, and configuring cerium nitrate and dimethyl oxalate respectively Mix and stir the aqueous ester solution, add carbon black to prevent agglomeration, react at 60°C for 20h, filter, wash and dry, then calcinate at 700°C for 2h to obtain cerium dioxide nanoparticles.

A Chinese patent application with publication number CN107522221A discloses a method for preparing cerium dioxide nanoparticles with an inorganic template, using cerium nitrate as a cerium source, ammonium bicarbonate as a template material, and the mass ratio of ammonium bicarbonate to cerium nitrate is Prepare the solution at 5:1, adjust the pH of the ammonium bicarbonate solution to 6.5-7.5, mix and stir at room temperature, centrifugally wash and dry, place the above complex in a muffle furnace, and calcinate at 450°C for 1.5 hours to obtain nano-dioxide cerium.

It can be seen from the above several preparation methods that the current methods for preparing high-quality ceria still have disadvantages such as easy agglomeration, high energy consumption, difficult disposal of waste gas and waste, and difficult application in large-scale production. Therefore, it is difficult to adopt a method that can effectively avoid agglomeration and consume less energy in the step of converting the precursor into ceria nanoparticles.

Contents of the invention

In order to solve the problem of easy agglomeration and high energy consumption in the preparation of ceria nanoparticles in the prior art, the present invention proposes a two-step method for preparing ceria nanoparticles based on the idea of first precipitation and then oxidation, which does not require high temperature The calcination energy consumption is low, and the primary particle diameter of the prepared ceria nanoparticles is within 5-15nm, and the secondary particle diameter is within 120-460nm. The method has the advantages of simple synthesis process, green, good reproducibility, high yield and the like.

A method for preparing ceria nanoparticles by a two-step method, the method adopts a strategy of first precipitating and then oxidation, and the specific steps are as follows:

(1) Dissolve the weighed Ce(NO ₃ ) ₃ 6H ₂ O (cerium nitrate hexahydrate) and NaOH (sodium hydroxide) in water respectively at room temperature;

(2) The two solutions obtained in step (1) were mixed and stirred for 15min, and precipitation occurred in the solution;

(3) The obtained precipitate is centrifugally washed and dried to obtain a cerium hydroxide sample;

(4) Expose the sample to the air for 1 to 1.5 days to slowly oxidize the surface;

(5) Disperse the obtained sample in water, and add 1-8 mL of 30% hydrogen peroxide solution in a water bath at 40° C. to oxidize again to obtain ceria nanoparticles.

Further, the molar ratio of Ce(NO ₃ ) ₃ ·6H ₂ O to NaOH is 1:4.

Further, the water bath time is 1-5 hours.

Further, in step (3), the obtained precipitate is centrifuged and washed three times with deionized water, and dried in a vacuum oven at 60° C. for 1 to 1.5 days.

Compared with the existing preparation technology, the present invention has the following advantages:

The primary particle size of the cerium oxide nanoparticles prepared by the method is within 5-15nm, and the secondary particle size is within 120-460nm. The synthesis process is simple, no high-temperature treatment is required, low requirements for equipment, green, good reproducibility, and high yield. high.

Description of drawings

FIG. 1 is an XRD pattern of ceria nanoparticles prepared in Example 1.

FIG. 2 is an SEM image of ceria nanoparticles prepared in Example 1.

FIG. 3 is a TEM image of ceria nanoparticles prepared in Example 1.

4 is a particle size analysis diagram of ceria nanoparticles prepared in Example 1.

FIG. 5 is an SEM image of ceria nanoparticles prepared in Example 2.

FIG. 6 is an SEM image of ceria nanoparticles prepared in Example 3.

FIG. 7 is an SEM image of ceria nanoparticles prepared in Example 4.

FIG. 8 is an SEM image of ceria nanoparticles prepared in Example 5.

Detailed ways

In order to understand the above-mentioned purpose, features and advantages of the present invention more clearly, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. In the following description, many specific details are set forth in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described here, therefore, the present invention is not limited to the specific embodiments disclosed below limit.

Example 1

At room temperature, weigh 5 mmol of cerium nitrate hexahydrate and 20 mmol of sodium hydroxide and dissolve them in water respectively, pour the cerium nitrate solution into the sodium hydroxide solution, stir for 15 minutes, wash with deionized water at high speed for three times, and put it in a vacuum at 60°C Dry in a drying oven for 1 day to obtain a cerium hydroxide sample, then expose the cerium hydroxide sample to the air for 1 day to allow it to oxidize slowly, then disperse the obtained sample in water, add 5 mL of 30% Hydrogen peroxide solution in a water bath at 40° C. for 2 h to obtain light yellow ceria nanoparticles. FIG. 1 is an XRD pattern of ceria nanoparticles prepared in this example.

FIG. 2 is an SEM image of ceria nanoparticles prepared in this example. FIG. 3 is a TEM image of ceria nanoparticles prepared in this example. Fig. 4 is a particle size analysis diagram of ceria nanoparticles prepared in this example. It can be known from Figures 1 to 4 that the nanomaterial synthesized in this example has a cubic fluorite structure and has a high purity. The primary particle diameter of the prepared cerium dioxide nanoparticles is within 5-15nm, and the secondary particle diameter is within 120-460nm.

Example 2

At room temperature, weigh 5 mmol of cerium nitrate hexahydrate and 20 mmol of sodium hydroxide and dissolve them in water respectively, pour the cerium nitrate solution into the sodium hydroxide solution, stir for 15 minutes, wash with deionized water at high speed for three times, and put it in a vacuum at 60°C Dry in a drying oven for 1 day to obtain a cerium hydroxide sample, then expose the cerium hydroxide sample to the air for 1 day to allow it to oxidize slowly, then disperse the obtained sample in water, add 5 mL of 30% hydrogen peroxide solution in a water bath at 40° C. for 1 h to obtain light yellow ceria nanoparticles. FIG. 5 is an SEM image of ceria nanoparticles prepared in this example.

Example 3

At room temperature, weigh 5 mmol of cerium nitrate hexahydrate and 20 mmol of sodium hydroxide and dissolve them in water respectively, pour the cerium nitrate solution into the sodium hydroxide solution, stir for 15 minutes, wash with deionized water at high speed for three times, and put it in a vacuum at 60°C Dry in a drying oven for 1 day to obtain a cerium hydroxide sample, then expose the cerium hydroxide sample to the air for 1 day to allow it to oxidize slowly, then disperse the obtained sample in water, add 5 mL of 30% hydrogen peroxide solution in a water bath at 40° C. for 3 h to obtain light yellow ceria nanoparticles. FIG. 6 is an SEM image of ceria nanoparticles prepared in this example.

Example 4

At room temperature, weigh 5 mmol of cerium nitrate hexahydrate and 20 mmol of sodium hydroxide and dissolve them in water respectively, pour the cerium nitrate solution into the sodium hydroxide solution, stir for 15 minutes, wash with deionized water at high speed for three times, and put it in a vacuum at 60°C Dry in a drying oven for 1 day to obtain a cerium hydroxide sample, then expose the cerium hydroxide sample to the air for 1 day to allow it to oxidize slowly, then disperse the obtained sample in water, add 5 mL of 30% hydrogen peroxide solution in a water bath at 40° C. for 4 h to obtain light yellow ceria nanoparticles. FIG. 7 is an SEM image of ceria nanoparticles prepared in this example.

Example 5

At room temperature, weigh 5 mmol of cerium nitrate hexahydrate and 20 mmol of sodium hydroxide and dissolve them in water respectively, pour the cerium nitrate solution into the sodium hydroxide solution, stir for 15 minutes, wash with deionized water at high speed for three times, and put it in a vacuum at 60°C Dry in a drying oven for 1 day to obtain a cerium hydroxide sample, then expose the cerium hydroxide sample to the air for 1 day to allow it to oxidize slowly, then disperse the obtained sample in water, add 5 mL of 30% hydrogen peroxide solution in a water bath at 40° C. for 5 h to obtain light yellow ceria nanoparticles. FIG. 8 is an SEM image of ceria nanoparticles prepared in this example.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (5)

1. A method for preparing cerium oxide nano particles by a two-step method, which is characterized by comprising the following specific steps:

(1) At normal temperature, the weighed Ce (NO ₃ ) ₃ ·6H ₂ O and NaOH are respectively dissolved in water;

(2) Mixing and stirring the two solutions obtained in the step (1) for 15min, wherein the solution precipitates;

(3) Centrifuging, washing and drying the obtained precipitate to obtain a cerium hydroxide sample;

(4) Exposing the cerium hydroxide sample in air for 1-1.5 days to oxidize the surface slowly;

(5) Dispersing the obtained sample in water, adding 1-8 mL of 30% hydrogen peroxide solution in mass fraction under the water bath condition of 40 ℃ for reoxidation to obtain the cerium dioxide nano particles.

2. The method for preparing cerium oxide nanoparticles by a two-step process according to claim 1, wherein said Ce (NO ₃ ) ₃ ·6H ₂ The molar ratio of O to NaOH was 1:4.

3. The method for preparing cerium oxide nanoparticles by a two-step process according to claim 1, wherein the water bath time is 1 to 5 hours.

4. The method for preparing cerium oxide nano particles by a two-step method according to claim 1, wherein in the step (3), the obtained precipitate is centrifugally washed three times with deionized water and then dried in a vacuum drying oven at 60 ℃ for 1 to 1.5 days.

5. The cerium oxide nanoparticle prepared by the method according to any one of claims 1 to 3, wherein the cerium oxide nanoparticle has a primary particle size of 5 to 15nm and a secondary particle size of 120 to 460 nm.

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