CN111333098B - Preparation method of cerium dioxide nano cube - Google Patents

Preparation method of cerium dioxide nano cube Download PDF

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CN111333098B
CN111333098B CN201811458907.7A CN201811458907A CN111333098B CN 111333098 B CN111333098 B CN 111333098B CN 201811458907 A CN201811458907 A CN 201811458907A CN 111333098 B CN111333098 B CN 111333098B
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cerium dioxide
dioxide nano
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CN111333098A (en
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王树东
王垚
苏宏久
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Dalian Institute of Chemical Physics of CAS
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer

Abstract

The application discloses a preparation method of cerium dioxide nano-cubic blocks, which comprises the following steps: (a) to obtain a catalyst containing Ce3+Ion, Ce4+Ion(s)And CH3COO‑A mixed solution A of ions; (b) mixing the solution A with alkali liquor B under the condition of inactive gas to obtain solution C containing precipitate; (c) under the condition of inactive gas, heating and aging the solution C containing the precipitate to obtain a suspension D, wherein the solution C contains NO3 ‑(ii) a (d) And carrying out solid-liquid separation on the suspension D to obtain the cerium dioxide nano cubic block. The method is simple and easy to implement, low in cost and high in yield, and cerium dioxide nano cubic blocks with uniform size, high crystallinity and good dispersibility are obtained.

Description

Preparation method of cerium dioxide nano cube
Technical Field
The application relates to a preparation method of cerium dioxide nano-cubes, belonging to the technical field of nano-material preparation.
Background
Rich rare earth resource in China, CeO2As a very important rare earth oxide which is cheap and has a wide application range, the rare earth oxide is widely used in automobile exhaust treatment, chemical mechanical polishing, solid fuel cells, photocatalysts, anticorrosive coatings, gas sensors, ionic thin films, cosmetics and plastic products.
The cerium dioxide belongs to fluorite crystal structure and is characterized by accompanying Ce4+/Ce3+The change in valence state, which can release or store oxygen and keep the crystal structure unchanged, therefore, ceria occupies an indispensable position in the catalytic reaction. Numerous studies show that the morphology and crystal face of cerium dioxide have a great influence on the catalytic effect in the catalytic reaction. Among the crystal planes of cerium oxide, the more common crystal planes are (100), (110), (111). Among the three crystal planes, the (100) crystal plane has the highest surface energy and the strongest oxygen storage and release capacity, and the (100) crystal plane can be fully exposed by the cubic cerium dioxide.
According to the reports of the prior documents, Yan et al (J.Phys. chem.B 2005,109,24380-24385) prepare nano cubic cerium dioxide under the hydrothermal reaction conditions of high-concentration alkali solution and 180 ℃ by adjusting the concentration of alkali and the reaction temperature in the reaction; yang et al (J.AM. CHEM. SOC.2006,128,9330-9331) prepared cerium dioxide nano cubic blocks with uniform size by adjusting the ratio of various reactants in a water/toluene/oleic acid system, wherein the oleic acid is used as a stabilizer and a blocking agent in the reaction, the ratio of water to toluene is also important, and the reaction condition is a hydrothermal reaction at 180 ℃; zhang et al (adv. Mater.2007,19,203-206) prepared nano-cubic ceria blocks with uniform size using capric acid under the conditions of 400 ℃ and supercritical hydrothermal. Subsequently, on the basis of the methods, the cerium dioxide nano cubic block is successfully prepared by related reports, but the preparation methods have the characteristics basically consistent with the three methods, namely high reaction temperature, complex reaction system and harsh reaction conditions. In summary, the preparation of the size-controllable ceria nano-cubic is a research hotspot, and so far, no simple, feasible, cheap and practical synthesis method can prepare the ceria nano-cubic with uniform size in high yield.
Disclosure of Invention
According to one aspect of the application, a preparation method of cerium dioxide nano-cubic blocks is provided, the method is simple and easy to implement, low in cost and high in yield, and the cerium dioxide nano-cubic blocks with uniform size, high crystallinity and good dispersibility are obtained.
The preparation method of the cerium dioxide nano cube comprises the following steps:
(a) to obtain a catalyst containing Ce3+Ion, Ce4+Ion and CH3COO-A mixed solution A of ions;
(b) mixing the solution A with alkali liquor B under the condition of inactive gas to obtain solution C containing precipitate;
(c) under the condition of inactive gas, heating and aging the solution C containing the precipitate to obtain a suspension D, wherein the solution C contains NO3 -；
(d) And carrying out solid-liquid separation on the suspension D to obtain the cerium dioxide nano cubic block.
In the step (a), the mixed solution A is a reaction starting solution, and the main body of the reaction starting solution is Ce3+Ions.
Alternatively, in solution A, Ce3+The ion is derived from Ce3+The soluble salt compound of Ce, the Ce4+The ion is derived from Ce4+The soluble salt compound of (1), the CH3COO-The ion is derived from CH3COO-The soluble salt compound of (1).
Specifically, Ce3+The soluble salt compound is selected from Ce3+Nitrate salt of (1), Ce3+Chlorine salt of (1), Ce3+Sulfate salt of (1), Ce3+For example, cerous nitrate hexahydrate may be used as at least one of the acetates of (a).
The Ce4+The soluble salt compound is selected from Ce4+For example, the nitrate or sulfate of (b) may be cerium ammonium nitrate, cerium sulfate, or cerium ammonium sulfate.
CH3COO-The soluble salt compound of (1), the CH3COO-The soluble salt compound is selected from ammonium acetate, sodium acetate, potassium acetate, Ce3+At least one of acetate salts of (a). For example, sodium acetate may be used.
Alternatively, in solution A, Ce4+Ion and Ce3+The molar ratio of ions is 1: 10000-1: 1. ce4+Ion and Ce3+The upper limit of the ion molar ratio is selected from 1: 100. 1: 26.7, 1: 4. 1: 1, Ce4+Ion and Ce3+The lower limit of the ion molar ratio is selected from 1: 10000. 1: 100. 1: 26.7, 1: 4.
alternatively, in solution A, CH3COO-Ion and Ce3+The molar ratio of ions is 1: 500-1: 1. CH3COO-Ion and Ce3+The upper limit of the molar ratio of the ions is selected from 1: 2. 1: 1.5, 1: 1, CH3COO-Ion and Ce3+The lower limit of the molar ratio of the ions is selected from 1: 500. 1: 2. 1: 1.5.
before the solution A is subjected to the next reaction, the solution A is preferably protected by using an inert gas in advance to ensure that the solution A is in an inert atmosphere state.
Step (b) is to form a reaction precursor.
Optionally, the alkali in the alkali liquor B is at least one selected from ammonia water, ammonia gas, organic amine and alkali metal hydroxide;
preferably, the hydroxide of the alkali metal is at least one of NaOH and KOH.
Preferably, the organic amine comprises at least one of monoethanolamine, diethanolamine, triethanolamine, propanolamine, methylamine.
In the step (B), the mixing temperature of the solution A and the alkali liquor B is 5-40 ℃.
Ce in solution A3+Ions and Ce4+The total number of moles of ions and OH in the alkali liquor B-Is 1: 5 or less.
After the alkali liquor B is prepared, preferably, an inert gas is used for protection in advance to ensure that the alkali liquor B is in an inert atmosphere state.
In the mixing process of the solution A and the alkali liquor B, the mixing process must be carried out in the presence of inactive gas.
The heat aging treatment in the step (c) is a post-heat treatment of the reaction system obtained in the step (b).
Optionally, the aging temperature of the heating and aging treatment is 60-90 ℃, and the aging time is 1-5 h.
The upper limit of the aging temperature of the heating and aging treatment is selected from 70 ℃, 80 ℃ and 90 ℃, and the lower limit of the aging temperature of the heating and aging treatment is selected from 60 ℃, 70 ℃ and 80 ℃.
The upper limit of the aging time is selected from 3h and 5h, and the lower limit of the aging time is selected from 1h and 3 h.
Alternatively, NO in solution C3 -Ion and Ce3+The molar ratio of ions is 1: 5-6: 1.
optionally, the solution A also contains nitric acid and/or a soluble nitrate.
Optionally, the lye B also contains soluble nitrates.
During the heating and ageing process, the reaction system must ensure that NO is contained3 -Ions. NO3 -The source of the ions may be Ce in the solution A3+And Ce4+Soluble nitrate-based compounds of (1), such as cerous nitrate, ceric ammonium nitrate; may also originate from the addition of nitric acid and/or soluble nitrates in solution A; can also be added from alkali liquor BIs added to the aqueous solution.
The solution C must be heated and aged in the presence of an inert gas.
Optionally, the inert gas is selected from at least one of nitrogen, carbon monoxide, noble gases. The rare gas means a gas formed of a group 0 element.
In the step (D), the suspension D is subjected to solid-liquid separation, and for example, a filtration method or a centrifugation method may be employed. The filter cake can be washed to remove soluble salt while solid-liquid separation is carried out. Drying the washed filter cake to obtain powder, and preparing the powder into colloidal suspension for storage.
According to another aspect of the present application, there is also provided cerium oxide nano-cubes obtained according to the above preparation method.
The beneficial effects that this application can produce include:
the preparation method of the cerium dioxide nano cube provided by the application is simple and easy to implement, low in cost and high in yield, and the prepared cerium dioxide nano cube is high in crystallinity, uniform in particle size and 10-40nm in particle size.
Drawings
FIG. 1 is an XRD pattern of sample # 1 prepared in example 1;
FIG. 2 is a TEM image of sample # 1 prepared in example 1;
FIG. 3 is a TEM image of sample # 1 prepared in example 2;
FIG. 4 is a TEM image of sample # 1 prepared in example 3;
fig. 5 is a TEM image of sample # 1 prepared in example 4.
Detailed Description
The present application will be described in detail with reference to examples, but the present application is not limited to these examples.
Unless otherwise specified, the raw materials and catalysts in the examples of the present application were all purchased commercially.
In this application, XRD analysis used an X' Pert PRO X-ray diffractometer from pananace (PANalytical) of the netherlands, Cu target, K α radiation source (λ ═ 0.15418nm), voltage 40KV, and current 40 mA.
TEM analysis was carried out using a JEM-2100 transmission electron microscope (JOEL corporation) with an electron gun LaB6 and an acceleration voltage of 200 kv.
Example 1
Solution A was prepared by adding 104.2g of cerous nitrate hexahydrate, 34.5g of ammonium ceric nitrate and 20.2g of sodium acetate to 1.2L of deionized water. The solution A was charged into a vessel and purged with nitrogen gas for 2 hours under stirring.
180ml of 28 wt% ammonia solution was mixed with 0.5L of deionized water to prepare an alkali solution B, which was placed in a reactor and purged with nitrogen gas for 2 hours while stirring. After 2 hours, the prepared solution a was added to an alkaline solution B containing ammonia to obtain a solution C.
After the mixing is finished, heating up is started, the temperature of the solution C is heated to 90 ℃, then the solution C is kept at 90 ℃ for 5 hours, suspension D is obtained, and nitrogen is continuously introduced in the heating up process and the heat preservation process.
After the reaction is finished, stopping introducing the nitrogen when the temperature of the reaction system is reduced to room temperature. And centrifuging the suspension D, dispersing the filter cake into the suspension by using deionized water, performing secondary centrifugal washing, and repeating for 3-5 times until the filtrate is neutral. And (4) putting the finally obtained filter cake into an oven, and drying at 60 ℃ to obtain cerium dioxide nano cubic blocks which are recorded as sample No. 1.
Example 2
Solution A was prepared by adding 104.2g of cerous nitrate hexahydrate, 34.5g of ammonium ceric nitrate and 20.2g of sodium acetate to 1.2L of deionized water. The solution A was charged into a vessel and purged with nitrogen gas for 2 hours under stirring.
64g of sodium hydroxide was dissolved in 0.6L of deionized water to prepare an alkali solution B, which was placed in a reactor and purged with nitrogen gas for 2 hours while stirring. After 2 hours, the prepared solution a was added to an alkali solution B containing sodium hydroxide to obtain a solution C.
After the mixing is finished, heating up is started, the temperature of the solution C is heated to 70 ℃, then the solution C is kept at 70 ℃ for 3 hours, suspension D is obtained, and nitrogen is continuously introduced in the heating up process and the heat preservation process.
After the reaction is finished, stopping introducing the nitrogen when the temperature of the reaction system is reduced to room temperature. And centrifuging the suspension D, dispersing the filter cake into the suspension by using deionized water, performing secondary centrifugal washing, and repeating for 3-5 times until the filtrate is neutral. And (4) putting the finally obtained filter cake into an oven, and drying at 60 ℃ to obtain cerium dioxide nano cubic blocks which are recorded as sample No. 2.
Example 3
Solution A was prepared by adding 104.2g of cerous nitrate hexahydrate, 1.3g of ammonium ceric nitrate and 7.9g of sodium acetate to 1.2L of deionized water. The solution A was charged into a vessel and purged with nitrogen gas for 2 hours under stirring.
48g of sodium hydroxide is dissolved in 0.6L of deionized water to prepare an alkali liquor B, the alkali liquor B is placed in a reactor, and nitrogen is introduced to purge the reactor for 2 hours under the stirring condition. After 2 hours, the prepared solution a was added to an alkali solution B containing sodium hydroxide to obtain a solution C.
After the mixing is finished, heating up is started, the temperature of the solution C is heated to 90 ℃, then the solution C is kept at 90 ℃ for 5 hours, suspension D is obtained, and nitrogen is continuously introduced in the heating up process and the heat preservation process.
After the reaction is finished, stopping introducing the nitrogen when the temperature of the reaction system is reduced to room temperature. And centrifuging the suspension D, dispersing the filter cake into the suspension by using deionized water, performing secondary centrifugal washing, and repeating for 3-5 times until the filtrate is neutral. And (4) putting the finally obtained filter cake into an oven, and drying at 60 ℃ to obtain cerium dioxide nano cubic blocks which are recorded as # 3 samples.
Example 4
Solution A was prepared by adding 104.2g of cerous nitrate hexahydrate, 5.0g of ceric ammonium nitrate, 12.0g of sodium nitrate, and 19.7g of sodium acetate to 1.2L of deionized water. The solution A was charged into a vessel and purged with nitrogen gas for 2 hours under stirring.
90ml of 28 wt% ammonia solution was mixed with 0.5L of deionized water to prepare an alkali solution B, which was placed in a reactor and purged with nitrogen gas for 2 hours while stirring. After 2 hours, the prepared solution a was added to an alkali solution B containing sodium hydroxide to obtain a solution C.
After the mixing is finished, heating up, heating the solution C to 80 ℃, then keeping the temperature at 80 ℃ for 3h to obtain a suspension D, and continuously introducing nitrogen in the heating up process and the heat preservation process.
After the reaction is finished, stopping introducing the nitrogen when the temperature of the reaction system is reduced to room temperature. And centrifuging the suspension D, dispersing the filter cake into the suspension by using deionized water, performing secondary centrifugal washing, and repeating for 3-5 times until the filtrate is neutral. And (4) putting the finally obtained filter cake into an oven, and drying at 60 ℃ to obtain cerium dioxide nano cubic blocks which are marked as # 4 samples.
Example 5 Crystal Structure testing
XRD crystal structure analysis was performed on samples # 1 to # 4, respectively, as shown typically in FIG. 1. Fig. 1 is an XRD pattern of sample # 1 prepared in example 1, and it can be seen from the pattern that the sample has high crystallinity, clearly showing the diffraction peak positions of the crystal planes of the cerium oxide structure (111), (200), (220), (311), (222), (400), (331), (420), (422).
The other samples had a similar XRD pattern to sample # 1, all having good crystallinity and a complete ceria crystal structure.
EXAMPLE 6 morphology testing of crystals
TEM lens morphology tests are respectively carried out on samples 1# -4 #, and the test results are shown in FIGS. 2-5. Fig. 2 is a TEM image of sample 1# prepared in example 1, fig. 3 is a TEM image of sample 1# prepared in example 2, fig. 4 is a TEM image of sample 1# prepared in example 3, and fig. 5 is a TEM image of sample 1# prepared in example 4.
As can be seen from FIGS. 2 to 5, the cerium oxide nano-cubes prepared in examples 1 to 4 have good uniformity and a particle size of 10 to 40 nm.
Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.

Claims (7)

1. A preparation method of cerium dioxide nano-cubic blocks is characterized by comprising the following steps:
(a) to obtain a catalyst containing Ce3+Ion, Ce4+Ion and CH3COO-A mixed solution A of ions;
(b) mixing the solution A with alkali liquor B under the condition of inactive gas to obtain solution C containing precipitate;
(c) under the condition of inactive gas, heating and aging the solution C containing the precipitate to obtain a suspension D, wherein the solution C contains NO3 -；
(d) Carrying out solid-liquid separation on the suspension D to obtain the cerium dioxide nano cubic block;
the Ce3+The ion is derived from Ce3+The soluble salt compound of Ce, the Ce4+The ion is derived from Ce4+The soluble salt compound of (1), the CH3COO-The ion is derived from CH3COO-Soluble salt compounds of (4);
in the solution A, Ce4+Ion and Ce3+The molar ratio of ions is 1: 10000-1: 1, CH3COO-Ion and Ce3+The molar ratio of ions is 1: 500-1: 1;
the alkali in the alkali liquor B is at least one selected from ammonia water, ammonia gas, organic amine and alkali metal hydroxide;
NO in the solution C3 -Ion and Ce3+The molar ratio of ions is 1: 5-6: 1;
the particle size of the cerium dioxide nano cube is 10-40 nm.
2. The method according to claim 1, wherein the organic amine comprises at least one of monoethanolamine, diethanolamine, triethanolamine, propanolamine, and methylamine.
3. The method according to claim 1, wherein the heating and aging temperature is 60 to 90 ℃ and the aging time is 1 to 5 hours.
4. The method according to claim 1, wherein the solution A further contains nitric acid and/or a soluble nitrate.
5. The method according to claim 1, wherein the lye B further comprises a soluble nitrate salt.
6. The production method according to claim 1, wherein the inert gas is at least one selected from the group consisting of nitrogen, carbon monoxide, and noble gases.
7. The cerium oxide nano-cube obtained by the preparation method according to any one of claims 1 to 6.
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