Monodisperse rare earth layered hydroxide nanostructure and preparation method thereof
Patent Information
- Application Number
- CN202610995731.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-06
- Publication Date
- 2026-09-29
AI Technical Summary
[0004]本发明的目的在于提供一种单分散稀土层状氢氧化物纳米结构及其制备方法，以解决现有技术中存在的相关技术问题
[0026]1、本发明的稀土层状氢氧化物，共计16种稀土元素，尺寸均一且分散性好。
Smart Images
Figure CN122831377A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of micro and nanomaterials technology, specifically a monodisperse rare earth layered hydroxide nanostructure and its preparation method. Background Technology
[0002] Rare earth layered hydroxides are a novel type of intercalated compound with a hydrotalcite-like structure. Their general chemical formula is Ln₂(OH)₅NO₃·nH₂O. They consist of positively charged hydroxide layers and interlayer anions arranged in a two-dimensional structure through electrostatic interactions. Due to their unique layered structure, rare earth layered hydroxides exhibit variable composition and rich intercalation chemical behavior. Furthermore, the excellent photoelectromagnetic and electromagnetic properties of rare earth ions further endow them with applications in luminescence, energy, catalysis, and biomedicine.
[0003] Traditional methods for preparing rare earth layered hydroxides involve homogeneous precipitation and hydrothermal processes. Specifically, this typically involves refluxing a soluble rare earth salt in an aqueous system with sodium hydroxide, ammonia, or hexamethylenetetramine, etc. However, due to the strong alkalinity of sodium hydroxide and ammonia, OH... - The rapid ion release rate leads to rapid product formation, making it difficult to control its size and morphology. Hexamethylenetetramine hydrolyzes slowly, effectively controlling product growth kinetics; however, the reaction requires an inert gas environment and is time-consuming, with formaldehyde as a byproduct further contributing to environmental problems. Furthermore, the preparation of single-atom-layer-thick rare-earth layered hydroxides requires lengthy organic molecule intercalation reactions, which are not only time-consuming but also inefficient, directly limiting their practical application. Existing preparation methods are insufficient for the large-scale production of rare-earth layered hydroxides, especially single-atom-layer-thick products, thus restricting their industrial application. Therefore, this invention proposes a monodisperse rare-earth layered hydroxide nanostructure and its preparation method to meet the requirements of controllable morphology and size, and green large-scale production, which is of great significance for the industrial preparation and application of rare-earth layered hydroxides. Summary of the Invention
[0004] The purpose of this invention is to provide a monodisperse rare earth layered hydroxide nanostructure and its preparation method, so as to solve the related technical problems existing in the prior art.
[0005] To achieve the above objectives, the present invention provides the following specific technical solutions: A monodisperse rare earth layered hydroxide nanostructure with the chemical formula Ln2(OH)5X·nH2O, where 0≤n≤2.
[0006] In a more optimized way, X is NO3. - (nitrate ions), Cl - (chloride ions), CH3COO -Any one of (acetic acid ions).
[0007] More optimally, Ln can be any one of Sc (scandium), Y (yttrium), La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), and Lu (lutetium).
[0008] In a more optimized manner, the rare earth layered hydroxide nanostructure has a flower-like or sheet-like morphology.
[0009] In a more optimized manner, when the rare earth layered hydroxide nanostructure is flower-shaped, the thickness of its single atomic layer is 1.0~1.5 nm.
[0010] A method for preparing monodisperse rare-earth layered hydroxide nanostructures includes the following steps: Rare earth salt solution and magnesium hydroxide dispersion were mixed and reacted. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain rare earth layered hydroxide nanostructures.
[0011] In a more optimized manner, the process conditions for the reaction are: reaction temperature: 20~160℃, reaction time: 2~7h.
[0012] In a more optimized manner, the reaction is an ultrasound-assisted reaction, and the process conditions for the ultrasound-assisted reaction are: ultrasonic treatment at a power of 30~50W for 30~40 minutes.
[0013] Ideally, the magnesium hydroxide in the magnesium hydroxide dispersion is magnesium hydroxide nanosheets.
[0014] In a more optimized manner, the magnesium hydroxide nanosheets are prepared by the following process: magnesium salt is dissolved in deionized water, ammonia is added to adjust the pH, and the reaction is carried out at a temperature of 20~200℃ for 2~3 hours. After the reaction is completed, the nanosheets are centrifuged, washed, and dried to obtain magnesium hydroxide nanosheets.
[0015] More preferably, the rare earth salt solution comprises rare earth salt and deionized water, with the mass ratio of rare earth salt to deionized water being (0.3~1):(20~30).
[0016] Ideally, the molar ratio of rare earth salt to magnesium hydroxide is (0.5~1):1.
[0017] Ideally, when the rare earth salt solution is a cerium salt solution, the reaction should be carried out in an inert gas atmosphere.
[0018] Ideally, the inert gas is either nitrogen or argon.
[0019] In a more optimized manner, when the rare earth salt solution is a neodymium salt solution, the specific preparation process of the magnesium hydroxide dispersion is as follows: magnesium hydroxide is added to an ethanol aqueous solution and ultrasonically dispersed to obtain a magnesium hydroxide dispersion; the concentration of the ethanol aqueous solution is 45~55 vol.
[0020] The optimal ultrasonic dispersion process conditions are as follows: ultrasonication at a power of 30-50W for 10-20 minutes.
[0021] Ideally, the magnesium salt is any one of magnesium nitrate, magnesium sulfate, or magnesium chloride.
[0022] In a more optimized manner, the specific process for adjusting the pH is as follows: using 25-30 wt% ammonia water to adjust the pH to 8-12.
[0023] Ideally, the centrifugation process conditions are as follows: centrifugation at a speed of 8000~9000 r / min for 5~10 min.
[0024] Ideally, the drying process conditions are as follows: drying at a temperature of 60~70℃ for 2~4 hours.
[0025] Compared with the prior art, the beneficial effects of the present invention are:
[0026] 1. The rare earth layered hydroxide of the present invention contains a total of 16 rare earth elements, with uniform size and good dispersibility.
[0027] 2. The rare earth layered hydroxide of the present invention can be rapidly prepared in large quantities, achieving a production capacity of 40~60g / L. It is simple to operate, requires no special equipment, and is inexpensive. Attached Figure Description
[0028] Figure 1 The XRD pattern of rare earth layered hydroxides from Example 1 is shown below. Figure 2 SEM and TEM images of rare earth layered hydroxides from Example 2; Figure 3 AFM image of rare earth layered hydroxide from Example 2; Figure 4 The images are SEM images of rare earth layered hydroxide nanostructures in Examples 3-8. A) is the SEM image of Example 3, B) is the SEM image of Example 4, C) is the SEM image of Example 5, D) is the SEM image of Example 6, E) is the SEM image of Example 7, and F) is the SEM image of Example 8. Figure 5 The images are SEM images of rare earth layered hydroxide nanostructures from Examples 9-10. A) is the SEM image of Example 9, and B) is the SEM image of Example 10. Figure 6 Here is a SEM image of the rare earth layered hydroxide nanostructure of Comparative Example 1. Figure 7 This is a SEM image of the rare earth layered hydroxide nanostructure in Comparative Example 2. Detailed Implementation
[0029] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. It should be understood that the embodiments described herein are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the protection scope of the present invention; unless otherwise specified, the related raw materials are all conventional settings.
[0030] In the following embodiments, there are no special limitations on any of the raw materials involved in this invention, and the following raw materials are included by way of example: Magnesium hydroxide nanosheets, product number: ZC-Mg(OH)2-OP1, average particle size 1μm, purity 98.5%; The concentration of the ethanol aqueous solution is 50 vol%. The concentration of ammonia water is 28 wt%.
[0031] Example 1:
[0032] A method for preparing monodisperse rare-earth layered hydroxide nanostructures includes the following steps: Weigh 1 mmol of magnesium nitrate and dissolve it in 20 mL of deionized water. Add ammonia solution to adjust the pH to 10. Stir magnetically at 60 °C for 2 h. After the reaction is complete, centrifuge at 8000 r / min for 10 min, wash three times with deionized water, and dry at 60 °C for 2 h to obtain magnesium hydroxide nanosheets. Magnesium hydroxide nanosheets were added to 20 mL of deionized water and ultrasonically dispersed at 30 W for 20 min. 0.8 mmol of rare earth salt gadolinium nitrate was added, and the mixture was reacted at 60 °C for 2 h. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 5 min, washed three times with deionized water, and dried at 60 °C for 2 h to obtain Gd2(OH)5NO3·2H2O.
[0033] Example 2:
[0034] A method for preparing monodisperse rare-earth layered hydroxide nanostructures includes the following steps: Weigh 1 mmol of magnesium nitrate and dissolve it in 20 mL of deionized water. Add ammonia solution to adjust the pH to 10. Stir magnetically at 60 °C for 2 h. After the reaction is complete, centrifuge at 8000 r / min for 10 min, wash three times with deionized water, and dry at 60 °C for 2 h to obtain magnesium hydroxide nanosheets. Magnesium hydroxide nanosheets were added to 20 mL of deionized water and ultrasonically dispersed at 30 W for 20 min. 0.8 mmol of rare earth salt gadolinium nitrate was added, and the mixture was reacted at 120 °C for 2 h. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 5 min, washed three times with deionized water, and dried at 60 °C for 2 h to obtain Gd2(OH)5NO3·2H2O.
[0035] Example 3:
[0036] A method for preparing monodisperse rare-earth layered hydroxide nanostructures includes the following steps: Weigh 1 mmol of commercially available magnesium hydroxide nanosheets and add them to 20 mL of deionized water. Disperse the mixture ultrasonically at 30 W for 20 min. Add 0.8 mmol of rare earth salt gadolinium nitrate and react with magnetic stirring at 20 °C for 2 h. After the reaction is complete, centrifuge at 8000 r / min for 5 min, wash three times with deionized water, and dry at 60 °C for 2 h to obtain Gd2(OH)5NO3·2H2O.
[0037] Example 4:
[0038] A method for preparing monodisperse rare-earth layered hydroxide nanostructures includes the following steps: Weigh 1 mmol of magnesium nitrate and dissolve it in 20 mL of deionized water. Add ammonia solution to adjust the pH to 10. Stir magnetically at 60 °C for 2 h. After the reaction is complete, centrifuge at 8000 r / min for 10 min, wash three times with deionized water, and dry at 60 °C for 2 h to obtain magnesium hydroxide nanosheets. Magnesium hydroxide nanosheets were added to 20 mL of deionized water and ultrasonically dispersed at 30 W for 20 min. 0.8 mmol of rare earth salt gadolinium nitrate was added and ultrasonically treated at 20 °C for 30 min at 30 W. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 10 min, washed three times with deionized water, and dried at 60 °C for 2 h to obtain Gd2(OH)5NO3·2H2O.
[0039] Example 5:
[0040] A method for preparing monodisperse rare-earth layered hydroxide nanostructures includes the following steps: Weigh 1 mmol of magnesium nitrate and dissolve it in 20 mL of deionized water. Add ammonia solution to adjust the pH to 10. Stir magnetically at 60 °C for 2 h. After the reaction is complete, centrifuge at 8000 r / min for 10 min, wash three times with deionized water, and dry at 60 °C for 2 h to obtain magnesium hydroxide nanosheets. Magnesium hydroxide nanosheets were added to 20 mL of deionized water and ultrasonically dispersed at 30 W for 20 min. 0.8 mmol of rare earth salt cerium nitrate was added, and the mixture was heated to react at 60 °C under a nitrogen atmosphere for 2 h. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 10 min, washed three times with deionized water, and dried at 60 °C for 2 h to obtain Ce2(OH)5NO3·2H2O.
[0041] Example 6:
[0042] A method for preparing monodisperse rare-earth layered hydroxide nanostructures includes the following steps: Weigh 1 mmol of magnesium nitrate and dissolve it in 20 mL of deionized water. Add ammonia solution to adjust the pH to 10. Stir magnetically at 60 °C for 2 h. After the reaction is complete, centrifuge at 8000 r / min for 10 min, wash three times with deionized water, and dry at 60 °C for 2 h to obtain magnesium hydroxide nanosheets. Magnesium hydroxide nanosheets were added to 20 mL of ethanol aqueous solution and ultrasonically dispersed at 30 W for 20 min. 0.8 mmol of rare earth salt neodymium nitrate was added, and the reaction was heated at 60 °C for 2 h. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 10 min, washed three times with deionized water, and dried at 60 °C for 2 h to obtain Nd2(OH)5NO3·2H2O.
[0043] Example 7:
[0044] A method for preparing monodisperse rare-earth layered hydroxide nanostructures includes the following steps: Weigh 1 mmol of magnesium nitrate and dissolve it in 20 mL of deionized water. Add ammonia solution to adjust the pH to 10. Stir magnetically at 60 °C for 2 h. After the reaction is complete, centrifuge at 8000 r / min for 10 min, wash three times with deionized water, and dry at 60 °C for 2 h to obtain magnesium hydroxide nanosheets. Magnesium hydroxide nanosheets were added to 20 mL of deionized water and ultrasonically dispersed at 30 W for 20 min. Then, 0.8 mmol of rare earth salt erbium nitrate was added, and the mixture was heated at 120 °C for 3 h. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 10 min, washed three times with deionized water, and dried at 60 °C for 2 h to obtain Er2(OH)5NO3·2H2O.
[0045] Example 8:
[0046] A method for preparing monodisperse rare-earth layered hydroxide nanostructures includes the following steps: Weigh 1 mmol of magnesium nitrate and dissolve it in 20 mL of deionized water. Add ammonia solution to adjust the pH to 10. Stir magnetically at 60 °C for 2 h. After the reaction is complete, centrifuge at 8000 r / min for 10 min, wash three times with deionized water, and dry at 60 °C for 2 h to obtain magnesium hydroxide nanosheets. Magnesium hydroxide nanosheets were added to 20 mL of deionized water and ultrasonically dispersed at 30 W for 20 min. Then, 0.8 mmol of rare earth salt lutetium nitrate was added, and the mixture was reacted at 120 °C for 6 h. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 10 min, washed three times with deionized water, and dried at 60 °C for 2 h to obtain Lu2(OH)5NO3·2H2O.
[0047] Example 9:
[0048] A method for preparing monodisperse rare-earth layered hydroxide nanostructures includes the following steps: Weigh 300 mmol of magnesium nitrate and dissolve it in 1000 mL of deionized water. Add ammonia solution to adjust the pH to 10. Stir magnetically at 60 °C for 2 h. After the reaction is complete, centrifuge at 8000 r / min for 10 min, wash three times with deionized water, and dry at 60 °C for 2 h to obtain magnesium hydroxide nanosheets. Magnesium hydroxide nanosheets were added to 1000 mL of deionized water and ultrasonically dispersed at 30 W for 20 min. Then, 240 mmol of rare earth salt gadolinium nitrate was added, and the mixture was reacted at 60 °C for 2 h. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 5 min, washed three times with deionized water, and dried at 60 °C for 2 h to obtain 50 g of Gd2(OH)5NO3·2H2O.
[0049] Example 10: A method for preparing monodisperse rare-earth layered hydroxide nanostructures includes the following steps: Weigh 300 mmol of commercially available magnesium hydroxide nanosheets and add them to 1000 mL of deionized water. Disperse the nanosheets by ultrasonication at 30 W for 20 min. Add 240 mmol of rare earth salt gadolinium nitrate and stir magnetically for 3 h at 20 °C. After the reaction is complete, allow the nanosheets to stand to remove unreacted large particles at the bottom. Centrifuge at 8000 r / min for 5 min, wash three times with deionized water, and dry at 60 °C for 2 h to obtain 40 g of Gd2(OH)5NO3·2H2O.
[0050] Comparative Example 1: A method for preparing rare earth layered hydroxide nanostructures includes the following steps: Weigh 1 mmol of rare earth salt gadolinium nitrate and dissolve it in 20 mL of deionized water. Add ammonia to adjust the pH to 8.0. Stir magnetically at 60 °C for 3 h. After the reaction is complete, centrifuge at 8000 r / min for 5 min, wash three times with deionized water, and dry at 60 °C for 2 h to obtain Gd2(OH)5NO3·1.2H2O.
[0051] Comparative Example 2: A method for preparing rare earth layered hydroxide nanostructures includes the following steps: Weigh 1 mmol of magnesium nitrate and dissolve it in 20 mL of deionized water. Add ammonia solution to adjust the pH to 10. Stir magnetically at 60 °C for 2 h. After the reaction is complete, centrifuge at 8000 r / min for 10 min, wash three times with deionized water, and dry at 60 °C for 2 h to obtain magnesium hydroxide nanosheets. Magnesium hydroxide nanosheets were added to 20 mL of deionized water and ultrasonically dispersed at 30 W for 20 min. 0.2 mmol of rare earth salt gadolinium nitrate was added, and the mixture was reacted at 60 °C for 2 h. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 5 min, washed three times with deionized water, and dried at 60 °C for 2 h to obtain Gd2(OH)5NO3·2H2O and Gd(OH)3.
[0052] Results and Discussion: Figure 1 The XRD pattern of the product prepared in Example 1 shows that the obtained product is a rare earth layered hydroxide phase; Figure 2 The images show SEM and TEM images of the product prepared in Example 2, indicating that the product is a monodisperse nanoflower ball; Figure 3 The image shows an AFM image of the product prepared in Example 2, indicating that the thickness of the flower head lamellae is approximately 1.2 nm, which is the thickness of a single atomic layer. Figure 4 SEM images of the products from Examples 3, 4, 5, 6, 7 and 8 show that the products are monodisperse nanofloral or elliptical nanosheet morphologies. Figure 5 The SEM images of the products from Examples 9 and 10 show that the large batches of products have a monodisperse nanoflower morphology. Compared to Example 1, Comparative Example 1 did not introduce magnesium hydroxide nanosheets. Figure 6 To compare the SEM images of the product from Example 1, it is shown that the product directly prepared using conventional ammonia water as the alkali source is an irregular sheet-like substance.
[0053] Compared to Example 1, Comparative Example 2 contained an excess of magnesium hydroxide nanosheets. Figure 7 To compare the SEM images of the product in Example 2, it is shown that magnesium hydroxide is in excess, and the resulting product is an irregularly shaped nanostructure. In addition to Gd2(OH)5NO3·2H2O, the product also contains the impurity phase Gd(OH)3.
[0054] In summary, the rare earth layered hydroxides prepared in this application, through component design and synergistic control of the ratio of magnesium hydroxide nanosheets to rare earth salts, yield nanostructures with uniform size, meeting the requirements for industrial-scale preparation.
[0055] For those skilled in the art, it is obvious that the present invention is not limited to the details disclosed in the exemplary embodiments described above. The present invention can be implemented in other specific ways without departing from its spirit and essential characteristics. Therefore, the foregoing embodiments should be considered exemplary rather than restrictive from any perspective. The scope of protection of the present invention is defined by the appended claims. Therefore, all variations falling within the meaning and scope of the equivalent elements of the claims should be attributed to the scope of the present invention.
Claims
1. A monodisperse rare-earth layered hydroxide nanostructure, characterized in that: Its chemical formula is Ln2(OH)5X·nH2O, 0≤n≤2; Ln is any one of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu; X is NO3. - Cl - CH3COO - Any one of them.
2. The monodisperse rare earth layered hydroxide nanostructure according to claim 1, characterized in that: The rare earth layered hydroxide nanostructure has a flower-like or sheet-like morphology.
3. The monodisperse rare earth layered hydroxide nanostructure according to claim 1, characterized in that: When the rare earth layered hydroxide nanostructure is flower-shaped, the thickness of its single atomic layer is 1.0~1.5 nm.
4. A method for preparing a monodisperse rare earth layered hydroxide nanostructure according to any one of claims 1-3, characterized in that: Includes the following steps: Rare earth salt solution and magnesium hydroxide dispersion were mixed and reacted to obtain rare earth layered hydroxide nanostructures.
5. The method for preparing a monodisperse rare earth layered hydroxide nanostructure according to claim 4, characterized in that: In the magnesium hydroxide dispersion, the magnesium hydroxide is magnesium hydroxide nanosheets; The magnesium hydroxide nanosheets are prepared by the following process: magnesium salt is dissolved in deionized water, ammonia is added to adjust the pH, and the reaction is carried out to obtain magnesium hydroxide nanosheets.
6. The method for preparing a monodisperse rare earth layered hydroxide nanostructure according to claim 4, characterized in that: The molar ratio of rare earth salts to magnesium hydroxide is (0.5~1):
1.
7. The method for preparing a monodisperse rare earth layered hydroxide nanostructure according to claim 4, characterized in that: The reaction process conditions are as follows: reaction temperature: 20~160℃, reaction time: 2~7h.
8. The method for preparing a monodisperse rare earth layered hydroxide nanostructure according to claim 4, characterized in that: The reaction is an ultrasound-assisted reaction, and the process conditions for the ultrasound-assisted reaction are: ultrasonic treatment at a power of 30~50W for 30~40 minutes.
9. The method for preparing a monodisperse rare earth layered hydroxide nanostructure according to claim 4, characterized in that: When the rare earth salt solution is a cerium salt solution, the reaction is carried out in an inert gas atmosphere; the inert gas is either nitrogen or argon.
10. The method for preparing a monodisperse rare earth layered hydroxide nanostructure according to claim 4, characterized in that: When the rare earth salt solution is a neodymium salt solution, the specific preparation process of the magnesium hydroxide dispersion is as follows: magnesium hydroxide is added to an ethanol aqueous solution and ultrasonically dispersed to obtain a magnesium hydroxide dispersion; the concentration of the ethanol aqueous solution is 45~55 vol.