Preparation method of cerium oxide-metal organic framework composite material

Abstract

The invention discloses a preparation method of a cerium oxide-metal organic framework composite material, which comprises the following steps: (1) preparing a solution A: dissolving cerium salt and hexamethylenetetramine in water to obtain the solution A; preparing a solution B: dissolving an organic ligand in an organic solvent to obtain the solution B; and (2) mixing the solution A and the solution B, heating, preserving heat, separating, washing and drying to obtain the cerium oxide-metal organic framework composite material. The spherical CeO2-MOF composite material is creatively synthesized under mild experimental conditions through a one-step method, and the composite material is good in dispersity and high in chemical activity.

Description

Technical Field

[0001] The invention belongs to the technical field of nano powder preparation, and specifically relates to a method for preparing a cerium oxide-metal organic framework composite material. Background Art

[0002] Due to its moderate Mohs hardness, high chemical reactivity, and abundant raw material resources, CeO2 is widely used as a polishing abrasive in the fields of optical glass, integrated circuits, liquid crystal displays, etc. With the extensive application of CeO2 powder in the polishing field, researchers have begun to explore methods to improve the performance of CeO2 by adjusting the morphology, size, crystallinity, and chemical activity of CeO2 through various synthesis conditions, and have made substantial research progress. In recent years, with the reduction of the feature size of integrated circuits, the improvement of chip integration, and the improvement of the precision of optical glass, more stringent requirements have been put forward for the physical and chemical properties of CeO2 particles. Generally, in order to prevent abrasive scratches on the surface of the polishing material and obtain an ultra-smooth surface, CeO2 particles are required to have nanoscale size, tend to be spherical, have good dispersibility in water, and have high chemical activity. These factors require more advanced CeO2 nanoparticle synthesis technology.

[0003] Therefore, it is urgent to develop a synthesis technology for CeO2 nanoparticles with good physical and chemical properties. At present, many researchers are working hard to synthesize CeO2 nanoparticles with different morphologies and chemical activities, and then study the effects of their properties on polishing performance. For example, Fang et al. synthesized monodispersed porous Nd-doped-CeO2 nanospheres by hydrothermal method. 3+ Ion doping, oxygen vacancies in CeO2 nanospheres and Ce 3+ The proportion of CeO2 increased significantly, resulting in a 56% increase in the removal rate of the silicon dioxide film compared to pure CeO2 nanospheres, while the Ra of the silicon dioxide film decreased by 63%. Although many scholars have explored the synthesis methods of CeO2 with different morphologies and chemical activities, the methods for synthesizing CeO2 with regular morphology are mostly hydrothermal methods. However, the hydrothermal method involves high temperature and high pressure reaction conditions and is not suitable for industrial production. Therefore, how to synthesize CeO2 nanoparticles with regular morphology and high chemical activity under mild conditions is still a difficult problem that restricts the application of CeO2 abrasives in high-end technologies. Summary of the invention

[0004] In view of the above problems, the present invention provides a method for preparing a cerium oxide-metal organic framework composite material, comprising the following steps: (1) Prepare Solution A: dissolve cerium salt and hexamethylenetetramine in water to obtain Solution A; Prepare liquid B: dissolve the organic ligand in an organic solvent to obtain liquid B; (2) Liquid A and Liquid B are mixed and heated and kept warm, and then separated, washed and dried to obtain a cerium oxide-metal organic framework composite material.

[0005] The cerium salt is one or more of cerium nitrate hexahydrate, cerium chloride, cerium acetate or cerium sulfate, preferably cerium nitrate hexahydrate.

[0006] The organic ligand in step (1) is one or more of 2-aminoterephthalic acid, terephthalic acid or trimesic acid; The molar ratio of the cerium salt to the organic ligand is 2:1 to 4:1.

[0007] The organic solvent in step (1) is one or more of N,N-dimethylacetamide and N,N-dimethylformamide; The mass ratio of the organic solvent to water is 1:9 to 7:3, preferably 2:1.

[0008] The molar ratio of the cerium salt to hexamethylenetetramine is 1:1 to 4:1.

[0009] The heating temperature in step (2) is 75-85°C, preferably 80°C.

[0010] The insulation time in step (2) is 3.5 h to 4.5 h, preferably 4 h.

[0011] The washing and drying process in step (2) is as follows: first wash with deionized water for 3 times, then wash with anhydrous ethanol for 3 times, and dry at 50-60° C. for 12-24 hours.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The present invention achieves one-step synthesis of spherical CeO2-MOF composite materials under mild reaction conditions without the need for hydrothermal reaction by introducing hexamethylenetetramine and adjusting the ratio of organic solvent to water, and the composite materials have uniform size. The composite material synthesized by the present invention is composed of ultra-small nano-cerium oxide and cerium-based metal organic framework, so the composite material has a large amount of Ce 3+ , high chemical activity, which is conducive to its application in the polishing field. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a SEM image of CeO2-MOF prepared in Example 1 of the present invention; Figure 2 is a SEM image of CeO2-MOF prepared in Comparative Example 1 of the present invention; Figure 3 This is the XPS graph of CeO2-MOF prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0014] The embodiments of the present invention will be described in detail below with reference to examples. The following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention.

[0015] Example 1 0.35 g of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) and 0.118 g of hexamethylenetetramine (HMT) were dissolved in 32.5 g of deionized water and ultrasonically dispersed for 10 min to form solution A. 0.073 g of 2-aminoterephthalic acid (NH2-BDC) was dissolved in 67.5 g of N,N-dimethylacetamide (DMA) to form solution B. Liquid A was poured into liquid B and mixed evenly. The mixture was heated to 80°C, kept warm for 4 hours, centrifuged at 4000 rpm for 10 minutes, washed with water and anhydrous ethanol 3 times each, dried at 60°C for 24 hours, and marked as CeO2-MOF-1.

[0016] Example 2 0.35 g of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) and 0.118 g of hexamethylenetetramine (HMT) were dissolved in 90 g of deionized water and ultrasonically dispersed for 10 min to form solution A. 0.073 g of 2-aminoterephthalic acid (NH2-BDC) was dissolved in 10 g of N,N-dimethylacetamide (DMA) to form solution B. Liquid A was poured into liquid B and mixed evenly. The mixture was heated to 80°C, kept warm for 4 hours, centrifuged at 4000 rpm for 10 minutes, washed with water and anhydrous ethanol 3 times each, dried at 60°C for 24 hours, and marked as CeO2-MOF-2.

[0017] Example 3 0.35 g of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) and 0.118 g of hexamethylenetetramine (HMT) were dissolved in 70 g of deionized water and ultrasonically dispersed for 10 min to form solution A. 0.073 g of 2-aminoterephthalic acid (NH2-BDC) was dissolved in 30 g of N,N-dimethylacetamide (DMA) to form solution B. Liquid A was poured into liquid B and mixed evenly. The mixture was heated to 80°C, kept warm for 4 hours, centrifuged at 4000 rpm for 10 minutes, washed with water and anhydrous ethanol 3 times each, dried at 60°C for 24 hours, and marked as CeO2-MOF-3.

[0018] Example 4 0.35 g of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) and 0.118 g of hexamethylenetetramine (HMT) were dissolved in 50 g of deionized water and ultrasonically dispersed for 10 min to form solution A. 0.073 g of 2-aminoterephthalic acid (NH2-BDC) was dissolved in 50 g of N,N-dimethylacetamide (DMA) to form solution B. Liquid A was poured into liquid B and mixed evenly. The mixture was heated to 80°C, kept warm for 4 hours, centrifuged at 4000 rpm for 10 minutes, washed with water and anhydrous ethanol 3 times each, dried at 60°C for 24 hours, and marked as CeO2-MOF-4.

[0019] Example 5 0.35 g of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) and 0.118 g of hexamethylenetetramine (HMT) were dissolved in 30 g of deionized water and ultrasonically dispersed for 10 min to form solution A. 0.073 g of 2-aminoterephthalic acid (NH2-BDC) was dissolved in 70 g of N,N-dimethylacetamide (DMA) to form solution B. Liquid A was poured into liquid B and mixed evenly. The mixture was heated to 80°C, kept warm for 4 hours, centrifuged at 4000 rpm for 10 minutes, washed with water and anhydrous ethanol 3 times each, dried at 60°C for 24 hours, and marked as CeO2-MOF-5.

[0020] Comparative Example 1 0.35 g of cerium nitrate hexahydrate (Ce(NO3)3·6H2O), 0.118 g of hexamethylenetetramine (HMT) and 0.073 g of 2-aminoterephthalic acid (NH2-BDC) were dissolved in 100 g of deionized water and ultrasonically dispersed for 10 min. The mixture was heated to 80°C, kept warm for 4 hours, centrifuged at 4000 rpm for 10 minutes, washed with water and anhydrous ethanol 3 times each, dried at 60°C for 24 hours, and labeled as CeO2-MOF-6.

[0021] Comparative Example 2 0.35 g of cerium nitrate hexahydrate (Ce(NO3)3·6H2O), 0.118 g of hexamethylenetetramine (HMT) and 0.073 g of 2-aminoterephthalic acid (NH2-BDC) were dissolved in 100 g of N,N-dimethylacetamide (DMA) and ultrasonically dispersed for 10 min. The mixture was heated to 80°C and kept warm for 4 hours without precipitation.

[0022] It can be seen from Examples 1-5 and Comparative Examples 1 and 2 that when pure water is used as the solvent, most of the CeO2-MOF composite materials are in irregular block-like accumulations, and a few are spherical. When pure N,N-dimethylacetamide is used as a solvent, due to the low synthesis temperature and atmospheric pressure, almost no CeO2-MOF composite precipitate is produced. However, we found that when DMA is introduced into water as a second solvent, the morphology of CeO2-MOF changes from irregular to regular spherical, and its size gradually decreases as the amount of DMA added increases. In particular, when m(water):m(DMA)=1:2, CeO2-MOF exhibits a good spherical structure.

[0023] In particular, from the XPS data, it can be seen that u′′′ (916.8 eV), u′′ (907.6 eV), u (903.3 eV), v′′′ (898.5 eV), v′′ (887.4 eV) and v (881.6 eV) belong to Ce 4+ ; at u′ (905.4 eV), u 0 (900.9eV), v′ (885.5 eV) and v 0 The peak at (879.5 eV) can be attributed to Ce 3+ ), CeO2-MOF has good chemical activity.

Claims

1. A method for preparing a cerium oxide-metal organic framework composite material, characterized in that: The following steps are involved: (1) Prepare Solution A: dissolve cerium salt and hexamethylenetetramine in water to obtain Solution A; Prepare liquid B: dissolve the organic ligand in an organic solvent to obtain liquid B; (2) Liquid A and Liquid B are mixed and heated and kept warm, and then separated, washed and dried to obtain a cerium oxide-metal organic framework composite material.

2. The method for preparing a cerium oxide-metal organic framework composite material according to claim 1, characterized in that: The cerium salt is one or more of cerium nitrate hexahydrate, cerium chloride, cerium acetate or cerium sulfate, preferably cerium nitrate hexahydrate.

3. The method for preparing a cerium oxide-metal organic framework composite material according to claim 1, characterized in that: The organic ligand in step (1) is one or more of 2-aminoterephthalic acid, terephthalic acid or trimesic acid; The molar ratio of the cerium salt to the organic ligand is 2:1 to 4:

1.

4. The method for preparing a cerium oxide-metal organic framework composite material according to claim 1, characterized in that: The organic solvent in step (1) is one or more of N,N-dimethylacetamide and N,N-dimethylformamide; The mass ratio of the organic solvent to water is 1:9 to 7:3, preferably 2:

1.

5. The method for preparing a cerium oxide-metal organic framework composite material according to claim 1, characterized in that: The molar ratio of the cerium salt to hexamethylenetetramine is 1:1 to 4:

1.

6. The method for preparing a cerium oxide-metal organic framework composite material according to claim 1, characterized in that: The heating temperature in step (2) is 75-85°C, preferably 80°C.

7. The method for preparing a cerium oxide-metal organic framework composite material according to claim 1, characterized in that: The insulation time in step (2) is 3.5 h to 4.5 h, preferably 4 h.

8. The method for preparing a cerium oxide-metal organic framework composite material according to claim 1, characterized in that: The washing and drying process in step (2) is as follows: first wash with deionized water for 3 times, then wash with anhydrous ethanol for 3 times, and dry at 50-60° C. for 12-24 hours.

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