Method for quantitatively preparing lamellar cerium dioxide
By controlling the reaction conditions and raw material ratio during the preparation process of nano ceria, stable sheet-like ceria was successfully prepared, which solved the problem of difficult control of particle size and morphology and unstable catalytic performance in the prior art, and achieved efficient and low-energy consumption quantitative preparation and industrial production.
Patent Information
- Application Number
- CN202510204148.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-24
- Publication Date
- 2025-05-13
AI Technical Summary
In the prior art, when preparing nano ceria, it is difficult to control the particle size and morphology, resulting in unstable catalytic performance, and the product morphology is easily changed during the expansion of production, affecting the catalytic performance.
Stable sheet-like cerium dioxide was prepared by mixing the soluble cerium salt solution with the precipitant solution, stirring, and solid-liquid separation, washing, drying and calcining. This method ensures the stability of the product's morphology and structure by controlling the reaction conditions and the proportion of raw materials.
Quantitative preparation of sheet-like ceria is realized, ensuring the morphology and structural stability of the product, and the catalytic performance does not decay when the raw material is doubled, making it suitable for industrial large-scale production.
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Figure CN119976924A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of nano functional material preparation, and more specifically relates to a method for quantitatively preparing lamellar cerium dioxide. Background Art
[0002] Cerium oxide (CeO2) is a material with unique physical and chemical properties, which is widely used in catalysis, energy storage, environmental protection and other fields. In particular, cerium oxide plays a vital role in automobile exhaust catalysts, fuel cells, photocatalysis and oxygen sensors. Its main feature is that it can 4+ and Ce 3+ The reversible redox reaction between cerium oxide and cerium oxide forms oxygen defects, thereby improving its catalytic activity. In addition, cerium oxide has a large specific surface area, high chemical stability and good thermal stability, making it an indispensable material in many industrial applications.
[0003] The catalytic performance of cerium oxide is closely related to its microstructure, especially the distribution of particle size, crystal morphology and surface defects. Therefore, how to optimize the preparation process of cerium oxide to control its particle size, morphology and surface defects has become an important topic in the current research on cerium oxide. At present, there are many methods for the preparation of CeO2, and since the corresponding properties of CeO2 are closely related to its morphology, the synthesis of its morphology has become an important way to adjust its performance. At present, many methods, including spray pyrolysis, sonochemistry and microwave-assisted thermal decomposition, electrosynthesis, homogeneous precipitation and hydrothermal methods, have been successfully used to prepare nano-cerium dioxide particles. In recent decades, CeO2 particles of various morphologies, including nanorods, nanotubes, nanowires and nanosheets, have been gradually developed, but they face the problems of difficulty in controlling particle size and morphology, high energy consumption and high production cost. That is, the morphology of the product obtained by the method existing in the laboratory often changes when the production is expanded, resulting in a significant change in its catalytic performance. Therefore, how to provide a method for preparing cerium dioxide that is efficient, low in energy consumption, and can be used for quantitative preparation without significantly changing the morphology or affecting its catalytic performance has become a difficult problem that urgently needs to be overcome in this field. Summary of the invention
[0004] The purpose of the present invention is to provide a method for quantitatively preparing lamellar cerium dioxide, so as to solve the problems existing in the above-mentioned prior art, realize the quantitative preparation of lamellar cerium dioxide, and the structure and morphology of the prepared cerium dioxide are stable.
[0005] To achieve the above object, the present invention provides the following solutions:
[0006] One of the technical solutions of the present invention is to provide a method for quantifiable preparation of lamellar cerium dioxide, the steps comprising:
[0007] The soluble cerium salt solution and the precipitant solution are mixed, stirred, and solid-liquid separation is performed to collect the solid product and the filtrate;
[0008] The solid product is washed, dried and calcined to obtain the lamellar cerium dioxide.
[0009] The filtrate obtained in the present invention can be recycled and used repeatedly as a solvent for preparing a soluble cerium salt solution and a precipitant solution.
[0010] Furthermore, the solvent of the soluble cerium salt solution includes ethanol or the filtrate.
[0011] Furthermore, the solvent of the precipitant solution includes water and / or the filtrate.
[0012] Furthermore, the precipitant in the precipitant solution is ammonium carbonate and / or ammonium bicarbonate.
[0013] Furthermore, the soluble cerium salt includes at least one of cerium nitrate, cerium acetate and cerium oxalate.
[0014] Furthermore, the molar volume ratio of the soluble cerium salt to the solvent in the soluble cerium salt solution is 10-25 mmol:20-200 mL.
[0015] Furthermore, the molar volume ratio of the precipitant to the solvent in the precipitant solution is 30-60 mmol: 20-200 mL.
[0016] Furthermore, the volume ratio of the solvent in the soluble cerium salt solution to the solvent in the precipitant solution is 1:1.
[0017] Furthermore, the stirring speed is 200-600 rpm and the time is 8-16 hours.
[0018] Furthermore, the washing is performed at least once using water and ethanol in sequence.
[0019] Furthermore, the drying temperature is 60-80° C. and the drying time is 6-12 hours.
[0020] Furthermore, the calcination temperature is 300-600°C, the heating rate is 1-5°C / min, and the time is 3-6h.
[0021] The second technical solution of the present invention is to provide a lamellar cerium dioxide prepared by the above method.
[0022] The present invention discloses the following technical effects:
[0023] The present invention provides a method for quantifiable preparation of lamellar cerium dioxide. Under the preparation method specified in the present application, even if the raw materials are doubled to prepare cerium dioxide, the morphology and structure of the prepared cerium dioxide will not change, and it has excellent stability and excellent performance, which provides certain technical support for the large-scale production of stable morphology of cerium dioxide. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:
[0025] Figure 1 This is the XRD spectrum of the product in Example 1.
[0026] Figure 2 The following are SEM images of the product of Example 1 at different magnifications.
[0027] Figure 3 The following are SEM images of the product of Example 2 at different magnifications.
[0028] Figure 4 These are SEM images of the product of Example 3 at different magnifications.
[0029] Figure 5 The following are SEM images of the product of Example 4 at different magnifications.
[0030] Figure 6 The following are SEM images of the product of Comparative Example 1 at different magnifications.
[0031] Figure 7 The following are SEM images of the product of Comparative Example 2 at different magnifications.
[0032] Figure 8 This is the SEM image of the product of Comparative Example 3.
[0033] Fig. 9 From left to right are CeO2 prepared in Examples 1-4. DETAILED DESCRIPTION
[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0035] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.
[0036] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.
[0037] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.
[0038] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.
[0039] Cerium nitrate, cerium acetate and cerium oxalate were selected because of their high solubility and thermal decomposition properties. They can be completely decomposed into CeO2 during calcination, while releasing gaseous byproducts (such as NO x , CO2) to avoid impurity residues. Anions regulate the crystallization behavior of precursors through coordination and promote the formation of layered precursors.
[0040] Ammonium carbonate / ammonium bicarbonate can provide a mild alkaline environment by controlling CO3 2- The release rate achieves uniform precipitation, and its low decomposition temperature (such as ammonium carbonate decomposes at about 58°C) ensures complete removal during calcination, avoiding interference of impurities with the final cerium dioxide product.
[0041] The introduction of ethanol reduces the polarity of the solution, regulates the anisotropic growth of crystals through interfacial tension, and promotes the formation of two-dimensional sheets. The filtrate is recycled by retaining trace amounts of NH4 + or CO3 2- , stabilize the ionic strength and pH of the reaction system, and also ensure morphology consistency.
[0042] The ratio of cerium salt (10-25mmol / 20-200mL) to precipitant (30-60mmol / 20-200mL) balances the nucleation and growth rates. At low concentrations, crystal growth is dominant, which is conducive to the expansion of the lamellar structure. The volume ratio of 1:1 ensures full contact between the reactants and avoids local concentration gradients.
[0043] The rotation speed of 200-600rpm provides moderate mixing to avoid high-speed shearing to damage the fragile precursor lamellae. The long reaction time of 8-16h ensures complete precipitation and directional growth of crystals. Water washing removes soluble salts, and ethanol washing replaces water to reduce drying stress and prevent structural collapse. Drying at 60-80℃ retains the structural integrity of the precursor; calcination at 300-600℃ matches the decomposition temperature of cerium carbonate (usually >300℃), and the heating rate of 1-5℃ / min relieves thermal stress and avoids sintering of lamellae. After calcination, CeO2 inherits the morphology of the precursor and forms a stable lamellae structure.
[0044] Filtrate reuse not only reduces waste liquid discharge, but also the residual NH4 + The pH of subsequent reactions can be adjusted, and trace Ce 3+ It may act as a seed to induce heterogeneous nucleation, improve batch-to-batch consistency, and achieve morphological stability in large-scale preparation.
[0045] The lamellar structure gives CeO2 a high specific surface area and exposed active crystal faces (such as the highly active {100} face), enhancing its catalytic oxidation performance. This method locks the morphology through parameter synergy to ensure that the performance does not decay in mass production, providing a reliable basis for industrial applications.
[0046] It can be seen that the present invention realizes the controllable preparation and large-scale stable output of lamellar cerium dioxide through raw material adaptation, ratio optimization, step coordination and cycle process design, and has both environmental friendliness and structure-performance advantages.
[0047] The raw materials and reagents used in the specific embodiments of the present invention are all commercially available products.
[0048] The "room temperature" and "normal temperature" involved in the specific implementation scheme of the present invention both refer to 20-30°C.
[0049] Example 1
[0050] Method for quantifying the preparation of lamellar cerium dioxide:
[0051] S1. Weigh 20 mmol of cerium nitrate and dissolve it in 100 mL of ethanol to prepare an ethanol solution of cerium nitrate;
[0052] S2, weigh 48mmol of ammonium bicarbonate and dissolve it in 100mL of water to prepare an aqueous solution of ammonium bicarbonate;
[0053] S3, quickly pouring the aqueous solution of ammonium bicarbonate obtained in step S2 into the ethanol solution of cerium nitrate obtained in step S1, stirring at room temperature for 12 h (400 rpm), filtering and separating to obtain a filtrate and a precipitated product, washing the precipitated product with deionized water and ethanol successively, repeating 3 times, and then drying in an oven at 80° C. for 12 h to obtain a light yellow powder;
[0054] S4. Place the light yellow powder obtained in step S3 in a muffle furnace, raise the temperature to 450° C. at 2° C. / min, and calcine for 5 h to obtain CeO2, about 2.8 g.
[0055] The CeO2 product obtained in Example 1 was subjected to X-ray diffraction (XRD), and its diffraction spectrum was as follows: Figure 1 As shown; the SEM image of CeO2 is as follows Figure 2 shown.
[0056] Example 2
[0057] Method for quantifying the preparation of lamellar cerium dioxide:
[0058] S1. Weigh 60 mmol of cerium nitrate and dissolve it in 300 mL of ethanol to prepare an ethanol solution of cerium nitrate;
[0059] S2, weigh 144mmol of ammonium bicarbonate and dissolve it in 300mL of water to prepare an aqueous solution of ammonium bicarbonate;
[0060] S3, quickly pouring the aqueous solution of ammonium bicarbonate obtained in step S2 into the ethanol solution of cerium nitrate obtained in step S1, stirring at room temperature for 12 h (400 rpm), filtering and separating to obtain a filtrate and a precipitated product, washing the precipitated product with deionized water and ethanol successively, repeating 3 times, and then drying in an oven at 80° C. for 12 h to obtain a light yellow powder;
[0061] S4. Place the light yellow powder obtained in step S3 in a muffle furnace, raise the temperature to 450° C. at a rate of 2° C. / min, and calcine for 5 h to obtain CeO2, about 8.4 g.
[0062] The SEM image of the CeO2 product obtained in Example 2 is as follows: Figure 3 shown.
[0063] Example 3
[0064] Method for quantifying the preparation of lamellar cerium dioxide:
[0065] S1, weighing 60 mmol of cerium nitrate and dissolving it in 300 mL of the filtrate separated in step S3 of Example 2 to prepare a cerium nitrate solution;
[0066] S2, weighing 144 mmol of ammonium bicarbonate and dissolving it in 100 mL of water, then adding 200 mL of the filtrate separated in step S3 of Example 2 to prepare an ammonium bicarbonate solution;
[0067] S3, quickly pouring the ammonium bicarbonate solution prepared in step S2 into the cerium nitrate solution prepared in step S1, stirring at room temperature for 12 hours (400 rpm), filtering and separating to obtain a filtrate and a precipitate product, washing the precipitate product with deionized water and ethanol successively, repeating 3 times, and then drying in an oven at 80° C. for 12 hours to obtain a light yellow powder;
[0068] S4. Place the light yellow powder obtained in step S3 in a muffle furnace, raise the temperature to 450° C. at a rate of 2° C. / min, and calcine for 5 h to obtain CeO2, about 8.4 g.
[0069] The SEM image of the CeO2 product obtained in Example 3 is as follows: Figure 4 shown.
[0070] Example 4
[0071] Method for quantifying the preparation of lamellar cerium dioxide:
[0072] S1. Weigh 100 mmol of cerium nitrate and dissolve it in 500 mL of ethanol to prepare an ethanol solution of cerium nitrate;
[0073] S2, weigh 240mmol of ammonium bicarbonate and dissolve it in 500mL of water to prepare an aqueous solution of ammonium bicarbonate;
[0074] S3, quickly pouring the aqueous solution of ammonium bicarbonate obtained in step S2 into the ethanol solution of cerium nitrate obtained in step S1, stirring at room temperature for 12 h (400 rpm), filtering and separating to obtain a filtrate and a precipitated product, washing the precipitated product with deionized water and ethanol successively, repeating 3 times, and then drying in an oven at 80° C. for 12 h to obtain a light yellow powder;
[0075] S4. Place the light yellow powder obtained in step S3 in a muffle furnace, raise the temperature to 450° C. at 2° C. / min, and calcine for 5 h to obtain CeO2, about 14 g.
[0076] The SEM image of the CeO2 product obtained in Example 4 is as follows: Figure 5 shown.
[0077] Comparative Example 1
[0078] Compared with Example 1, the difference is that the ethanol in step S1 is replaced by an equal volume of deionized water, and the calcination temperature in step S4 is 500°C.
[0079] The SEM image of the CeO2 product obtained in Comparative Example 1 is as follows: Figure 6 shown.
[0080] Comparative Example 2
[0081] Compared with Example 4, the differences are that the ethanol in step S1 is replaced by an equal volume of deionized water, the calcination temperature in step S4 is 500° C., and the precipitant is ammonium carbonate.
[0082] The SEM image of the CeO2 product obtained in Comparative Example 2 is as follows: Figure 7 shown.
[0083] Comparative Example 3
[0084] Compared with Comparative Example 2, the only difference is that the calcination temperature in step S4 is 400°C.
[0085] The SEM image of the CeO2 product obtained in Comparative Example 3 is as follows: Figure 8 shown.
[0086] Depend on Figure 2-Figure 5 It can be seen from the SEM images of the products of Examples 1-4 that, when the method of the present invention is used to quantitatively prepare cerium dioxide, doubling the raw materials will not affect the morphology of the product. Figure 2-Figure 5 The results show that the cerium dioxide is in the form of lamellar sheets, indicating that the preparation method of the present invention can be used for industrial mass production of CeO2, thereby improving the preparation efficiency of the product. At the same time, the filtrate byproduct in the preparation process of the present invention can be reused, thereby maximizing the reagent utilization rate and reducing the production cost.
[0087] Depend on Figure 6-Figure 8 It can be seen that when the comparative method is adopted, the morphology of the product changes significantly when the raw material is doubled or the calcination temperature is changed.
[0088] Fig. 9 From left to right are CeO2 prepared in Examples 1-4.
[0089] The lamellar cerium dioxide prepared by the present invention exhibits excellent activity and selectivity in catalytic reactions due to its unique structure and large specific surface area. The method can be used for large-scale production of cerium dioxide catalysts with specific morphology, and is suitable for various catalytic processes such as automobile exhaust purification and chemical synthesis. In the fields of waste gas treatment and water pollution control, cerium dioxide-based materials can be used as efficient adsorbents or photocatalysts. The lamellar cerium dioxide prepared by the method of the present invention is expected to improve the performance of these environmentally friendly materials.
[0090] At the same time, cerium dioxide, as a solid electrolyte material, is widely used in solid oxide fuel cells (SOFCs). The quantifiable cerium dioxide material obtained by the preparation method optimized by the present invention is expected to improve the efficiency and durability of fuel cells. Cerium dioxide can also be used as a high-performance electrode material in supercapacitors and lithium-ion batteries. The lamellar structure helps to improve electrochemical performance, such as increasing electrical capacity and shortening charge and discharge time.
[0091] Moreover, with the growing demand for nanomaterials, preparation methods that can precisely control morphology and size have become particularly important. The preparation strategy provided by the present invention provides the possibility for the development of new functional materials.
[0092] Lamellar cerium dioxide can also be used as a protective coating on the surface of metals or other materials to improve corrosion resistance and wear resistance.
[0093] The present invention recycles the filtrate, which not only reduces production costs, but also reduces waste emissions, conforms to the principles of green chemistry, and is conducive to achieving sustainable development goals. Since the method can maintain product consistency when the raw materials are doubled, it is very suitable for industrial large-scale production, meeting market demand while ensuring product quality.
[0094] In summary, the method for quantifiable preparation of lamellar cerium dioxide provided by the present invention has broad application prospects, and with the deepening of research and the advancement of technology, more potential application fields may be discovered. At the same time, the development of this technology will also promote the innovation and upgrading of related industries.
[0095] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.
[0096] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for quantifying the preparation of lamellar cerium dioxide, characterized in that the steps include: The soluble cerium salt solution and the precipitant solution are mixed, stirred, and solid-liquid separation is performed to collect the solid product and the filtrate; The solid product is washed, dried and calcined to obtain the lamellar cerium dioxide.
2. The method according to claim 1, characterized in that The solvent of the soluble cerium salt solution includes ethanol or the filtrate; and / or the solvent of the precipitant solution includes water and / or the filtrate.
3. The method according to claim 1, characterized in that The precipitant in the precipitant solution is ammonium carbonate and / or ammonium bicarbonate.
4. The method according to claim 1, characterized in that The soluble cerium salt includes at least one of cerium nitrate, cerium acetate and cerium oxalate.
5. The method according to claim 1, characterized in that The molar volume ratio of the precipitant to the solvent in the precipitant solution is 30-60 mmol: 20-200 mL; and / or the molar volume ratio of the soluble cerium salt to the solvent in the soluble cerium salt solution is 10-25 mmol: 20-200 mL.
6. The method according to claim 5, characterized in that The volume ratio of the solvent in the soluble cerium salt solution to the solvent in the precipitant solution is 1:
1.
7. The method according to claim 1, characterized in that The stirring speed is 200-600 rpm and the time is 8-16 hours.
8. The method according to claim 1, characterized in that The washing is performed at least once using water and ethanol in sequence.
9. The method according to claim 1, characterized in that The drying temperature is 60-80°C and the time is 6-12h; and / or the calcination temperature is 300-600°C, the heating rate is 1-5°C / min and the time is 3-6h.
10. A lamellar cerium dioxide prepared quantitatively by the method according to any one of claims 1 to 9.