Preparation method for synthesizing rare earth fluoride NaReF4 nanorod under assistance of catalyst
Through the catalyst-assisted synthesis method, the problem of morphology and size regulation of rare earth fluoride NaReF4 nanorods was solved, and a nanorod structure with uniform particle size and high aspect ratio was realized, simplifying the preparation process and expanding its application range.
Patent Information
- Application Number
- CN202310688183.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-12
- Publication Date
- 2024-12-13
AI Technical Summary
The existing rare earth fluoride synthesis methods are difficult to achieve high uniformity of morphological characteristics and the preparation of rod-shaped nanostructures, especially in biomedical applications, where particle size is uneven and morphological inadequate.
The catalyst-assisted synthesis method is adopted to regulate the intermediate cubic phase stability and relative growth rate of the rare earth fluoride NaReF4 by adding a catalyst such as Fe3+ to the reaction system, and the formation of nanorod structures with uniform particle size and high aspect ratio is achieved.
The morphology and size control of the rare earth fluoride NaReF4 nanorod is achieved, simplifying the preparation process, and expanding its application potential in the fields of anti-Stokes luminescence, polarization optics, environmental detection and biomedical diagnosis and treatment.
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Figure CN119118182A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of nano materials and relates to a method for preparing rare earth fluoride NaReF4 nanorods by catalyst-assisted synthesis. Background Art
[0002] The properties of nanomaterials are closely related to their crystals, morphology, size and dimensions, and the synthesis method profoundly determines many properties of nanomaterials. Therefore, the controlled synthesis of nanomaterials is of great significance in the fields of modern chemistry and materials science. In particular, for the synthesis of rare earth fluorides, due to their lower phonon energy and better resistance to water absorption compared to rare earth oxides, they are often used as carriers of other optical materials such as upconversion. The morphological characteristics of rare earth fluorides have a huge impact on their optical properties. For example, rod-shaped rare earth nanomaterials have stronger fluorescence properties than spherical granular materials of equivalent radius, and also have potential polarized optical properties. In biomedicine and other aspects, related studies have found that the aspect ratio of nanomaterials is closely related to the cell uptake rate. All these have made them attract much attention in terms of application and synthesis, so the synthesis of a rod-shaped rare earth nanomaterial is of great value.
[0003] At present, the synthesis of rare earth fluoride luminescent materials includes solvothermal method, hydrothermal method, solid phase reaction, etc. For the hydrothermal method, the obtained rod-shaped rare earth fluoride is usually (sub) micron-sized, and it is impossible to achieve highly uniform morphology, which seriously limits its application in in vivo biomedicine and other fields; for the ordinary solvothermal method, although the particle size of the obtained product is relatively uniform, it is mostly round particles. If the preparation of rod-shaped nanoparticles is to be achieved, strict control of doping components, structural regulation, chelating agents, etc. is required, and the conditions are complex and harsh, and it is often difficult to achieve; for the high-temperature solid phase method, the morphology of the synthesized crystals cannot be controlled and is easy to agglomerate. Summary of the invention
[0004] The purpose of the present invention is to address the above-mentioned problems existing in the prior art and to propose a method for preparing rare earth fluoride NaReF4 nanorods by catalyst-assisted synthesis, which does not require complex and harsh conditions such as component doping, is simple to operate, is precisely controllable, and can synthesize rod-shaped nanorods with uniform morphology and size, high aspect ratio, and monodispersity.
[0005] The purpose of the present invention can be achieved by the following technical solutions:
[0006] A method for preparing rare earth fluoride NaReF4 nanorods by catalyst-assisted synthesis, the preparation method comprising:
[0007] (1) After mixing a rare earth compound, a catalyst, oleic acid, and 1-octadecene in a reaction container, the reaction container is continuously evacuated and a first heating reaction is performed;
[0008] (2) dissolving the F source and the Na source in a solvent respectively and mixing them, then dropping them into the solution obtained in (1) and performing a second heating reaction;
[0009] (3) introducing nitrogen gas into the solution obtained in (2) and performing a third heating reaction;
[0010] (4) continuing to introduce nitrogen into the solution obtained in (3) and performing a fourth heating reaction;
[0011] (5) The solution obtained in (4) is centrifuged, washed, and dried to obtain catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods.
[0012] In the present invention, a catalyst (such as Fe 3+ ) to assist in the synthesis of nanorod-shaped rare earth fluoride NaReF4, by using a catalyst (such as Fe 3+ ) catalytic effect, improves the stability of the intermediate cubic phase of rare earth fluoride, thereby affecting the process of transformation from the intermediate cubic phase rare earth fluoride to the hexagonal phase NaReF4, and affects the relative growth rate of the hexagonal phase NaReF4 (001) and other crystal directions, thereby facilitating the formation of rod-shaped nanocrystalline materials.
[0013] The rare earth fluoride NaReF4 prepared by the conventional raw material system of rare earth compounds, oleic acid, 1-octadecene, F source, and Na source is mostly one-dimensional round particles, while the realization of a two-dimensional rod-like structure, especially a two-dimensional rod-like nanostructure with highly uniform morphology, has relatively strict conditions and restrictions on factors such as rare earth ion types, components, structures, and chelating agents. Currently, the most common report on rod-like NaReF4 is NaGdF4, while the preparation of other types of rods such as NaYF4 requires doping with different types of elements in a specific proportion, but the content and type of doped elements have an extremely critical influence on the physical and chemical properties and functional application design of NaReF4; this greatly limits the regulation of the effective morphology and adjustment of the physical and chemical properties of rare earth fluoride nanostructures, and is not convenient for further application development.
[0014] The present invention synthesizes rare earth fluoride NaReF4 nanorods by catalyst assistance. 3+ ) in the reaction system, the rare earth fluoride NaReF4 is regulated to be nanorods with uniform particle size, high aspect ratio and adjustable size, and these catalysts do not participate in the formation of the nanoproduct component structure but can affect the nanoproduct phase formation process and nanocrystal growth rate.
[0015] Preferably, the rare earth compound is a compound formed by a rare earth element Re and a halogen element; Re specifically includes one or more of Er, Tm, Yb, Dy, Lu, Ho, Tb, Gd, Eu, Sm, Pm, Nd, Pr, Ce, La, Y, and Sc.
[0016] Preferably, the catalyst in (1) is a compound containing transition metal ions.
[0017] More preferably, the catalyst in (1) comprises one or more of a trivalent iron compound, a manganese-containing compound, a chromium-containing compound, and a ruthenium-containing compound.
[0018] These catalysts do not participate in the formation of the nano-product component structure, but can affect the nano-product phase formation process and nano-crystal growth rate.
[0019] Preferably, when the catalyst is a trivalent iron compound, the catalyst is an iron salt, specifically including one or more of FeCl3, Fe(NO3)3, (CH3COO)3Fe.
[0020] Preferably, in (1) above, the amount of the catalyst accounts for 10 to 95% of the total amount of the rare earth compound and the catalyst.
[0021] Preferably, in (2), before the reaction, the ratio of the total amount of catalyst and rare earth compounds in the solution to the amount of Na source is 1:(1-5); the ratio of the total amount of catalyst and rare earth compounds in the solution to the amount of F source is:(2-10).
[0022] If the amount of F source and Na source added is too much, it will lead to the generation of too much NaF or other impurity by-products; if the amount added is too little, it will lead to the lack of component ions of the target product, resulting in problems such as small product amount or uneven morphology.
[0023] Preferably, the vacuum degree of the first heating reaction in (1) is ≤0.08Mpa; the heating temperature is 100-180°C, and the heating and heat preservation time is 1-60min.
[0024] Preferably, the rare earth compound and the catalyst Fe in (1) 3+ The total mass ratio of oleic acid and 1-octadecene to the total volume ratio is (50-1000) mg: (10-100) ml.
[0025] Preferably, the heating temperature of the second heating reaction in (2) is 20 to 60° C., and the heating and heat preservation time is 1 to 60 min.
[0026] Preferably, the dripping speed in (2) is 0.1 to 5 ml / s.
[0027] Preferably, in said (2), the F source and the Na source are dissolved in solvents respectively, the concentration of the F source is 15-30 mg / ml, and the concentration of the Na source is 20-50 mg / ml.
[0028] More preferably, the solvent in (2) is one of methanol and ethanol.
[0029] Preferably, in (2), the F source is NH4, and the Na source is NaOH; the F source and the Na source may both be NaF.
[0030] Preferably, the heating temperature of the third heating reaction in (3) is 100-200° C., and the heating and heat preservation time is 1-20 min.
[0031] Preferably, after the third heating reaction in (3) is completed, vacuum is evacuated until there are no bubbles in the solution.
[0032] This step involves vacuuming to fully remove low-boiling impurities such as methanol and water vapor in the solution.
[0033] Preferably, the heating temperature of the fourth heating reaction in (4) is 230-350° C., and the heating and heat preservation time is 70-300 min.
[0034] Nitrogen is introduced into steps (3) and (4) to serve as a protective gas to ensure the safety of the experiment.
[0035] Preferably, the centrifugal speed in (5) is 4000-9000 rpm / min.
[0036] Preferably, the washing liquid in the centrifugation and washing process in (5) is one or more of ethanol, methanol and cyclohexane.
[0037] Preferably, the drying process in (5) is carried out at a temperature of 50 to 90° C. and for a time of 6 to 20 hours.
[0038] A catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods, which have a diameter of 8-45nm, a length of 20-200nm and an aspect ratio of 1-20.
[0039] In the present invention, as long as the catalyst is added to the system, the morphology of the NaReF4 nanomaterial begins to change to nanorods. When the amount of the added catalyst accounts for 10 to 95% of the total amount of the rare earth compound and the catalyst, all the nanoparticles in the system can be controlled to be converted into nanorods; and as the proportion of the added catalyst increases, the aspect ratio of the catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods tends to increase. The present invention can achieve effective regulation of parameters such as the particle size and aspect ratio of the NaReF4 nanorods by adjusting the addition ratio of the catalyst in the raw material, without limiting the type and content of the rare earth element ions, without the need to regulate the morphology of doping element ions of different radii and properties, and without the need for strict regulation of chelating agents such as oleic acid and other factors and conditions.
[0040] A catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods for use in anti-Stokes luminescence, polarization optics, environmental monitoring, optical imaging, biomedical diagnosis and treatment, and other fields.
[0041] Compared with the prior art, the present invention has the following beneficial effects:
[0042] 1. The catalyst-assisted synthesis method of the present invention is to add a catalyst to the raw material system to adjust the morphology of the rare earth fluoride NaReF4 into nanorods with uniform particle size, high aspect ratio and adjustable size; and the catalyst does not participate in the composition of the product.
[0043] 2. The catalyst-assisted synthesis method of the rare earth fluoride NaReF4 nanorods of the present invention has no strict restrictions on the synthesis of one-dimensional nanorods due to a series of complex factors such as the type of rare earth ion elements, the content of doping component elements and chelating agents, and the preparation is simple and easy; and it is expected that the content of nano components can be arbitrarily adjusted under the condition of rod-like morphology, thereby achieving optimal physical and chemical properties to maximize its application potential.
[0044] 3. The catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods prepared by the preparation method of the catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods of the present invention can be applied to anti-Stokes luminescence, polarization optics, environmental detection, optical imaging, biomedical diagnosis and treatment and other fields; compared with round nanoparticles, it has a wider range of applications and better performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0045] Figure 1 This is a TEM image of the rare earth fluoride NaReF4 nanorods prepared in Example 1 of the present invention.
[0046] Figure 2 Mapping diagram and EDS analysis diagram of the rare earth fluoride NaReF4 nanorods prepared in Example 1 of the present invention.
[0047] Figure 3 This is a TEM image of the rare earth fluoride NaReF4 nanorods prepared in Example 2 of the present invention.
[0048] Figure 4 This is a TEM image of the rare earth fluoride NaReF4 nanorods prepared in Example 3 of the present invention.
[0049] Figure 5 This is a TEM morphology image of the rare earth fluoride NaReF4 nano-synthesized without catalyst assistance obtained in comparative example 1 of the present invention.
[0050] Figure 6 This is a TEM morphology image of the low-content catalyst-assisted synthesis of rare earth fluoride NaReF4 nanoparticles prepared in Comparative Example 2 of the present invention. DETAILED DESCRIPTION
[0051] The following are specific embodiments of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.
[0052] Unless otherwise specified, the materials used in the present invention are conventional commercial products, and the methods used are conventional technical means.
[0053] The catalyst-assisted preparation method of rare earth fluoride NaReF4 nanorods of the present invention comprises:
[0054] (1) placing a rare earth compound and a catalyst into a reaction vessel;
[0055] Re in the rare earth compound is any rare earth element, specifically including one or more of Er, Tm, Yb, Dy, Lu, Ho, Tb, Gd, Eu, Sm, Pm, Nd, Pr, Ce, La, Y, and Sc;
[0056] Continue to add 3-18 ml of oleic acid (OA) and 9-18 ml of 1-octadecene (OED) into the reaction container and mix well;
[0057] In the above (1), the amount of the catalyst accounts for 10 to 95% of the total amount of the rare earth compound and the catalyst;
[0058] The total mass ratio of the added rare earth compound and catalyst to the added oleic acid and 1-octadecene is (50-1000) mg: (10-100) ml;
[0059] Then the reaction container is continuously evacuated and a first heating reaction is performed;
[0060] The vacuum degree in the reaction container is ≤0.08Mpa; the heating temperature of the first heating reaction is 100-180°C, and the heating and heat preservation time is 1-60min;
[0061] (2) dissolving the F source in a solvent, wherein the concentration of the F source is 15 to 30 mg / ml; dissolving the Na source in a solvent, wherein the concentration of the Na source is 20 to 50 mg / ml; then mixing the two and dropping them into the solution obtained in (1), wherein the ratio of the total amount of the catalyst and the rare earth compound in the solution to the amount of the Na source is 1:(1 to 5); and the ratio of the total amount of the catalyst and the rare earth compound in the solution to the amount of the F source is:(2 to 10);
[0062] Then a second heating reaction is performed;
[0063] The second heating reaction is heated at a temperature of 20 to 60°C and the heating and heat preservation time is 1 to 20 minutes;
[0064] (3) introducing nitrogen into the solution obtained in (2) and performing a third heating reaction; after the third heating reaction, evacuating the solution until there are no bubbles in the solution, and fully removing low-boiling impurities such as methanol and water vapor in the solution;
[0065] The third heating reaction is carried out at a heating temperature of 100 to 200° C. and a heating and heat preservation time of 1 to 20 minutes;
[0066] (4) continuing to introduce nitrogen into the solution obtained in (3) and performing a fourth heating reaction, followed by natural cooling;
[0067] The fourth heating reaction heating temperature is 230-350° C., and the heating and heat preservation time is 70-300 min;
[0068] (5) centrifuging, washing and drying the solution obtained in (4) to obtain a powdered catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods;
[0069] The centrifugal speed is 4000~9000rpm / min;
[0070] The washing liquid in the centrifugation and washing process is one or more of ethanol, methanol, and cyclohexane;
[0071] The drying process temperature is 50-90°C and the time is 6-20 hours.
[0072] The catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods prepared by the preparation method of the catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods of the present invention has a diameter of 8 to 45 nm, a length of 20 to 200 nm, and an aspect ratio of 1 to 20; the catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods can be applied to the fields of anti-Stokes luminescence, polarization optics, environmental detection, optical imaging, biomedical diagnosis and treatment;
[0073] When catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods is used for anti-Stokes luminescence, the upconversion luminescence intensity is enhanced by 2 to 10 times compared with the rare earth fluoride nanorods synthesized without catalyst assistance under the same conditions.
[0074] Example 1
[0075] Catalyst (Fe 3+ ) assisted synthesis of rare earth fluoride NaReF4 nanorods preparation method:
[0076] (1) Add 267.0 mg ErCl3·6H2O and 108.0 mg FeCl3·6H2O to a reaction flask, and then add 6 ml OA and 15 ml OED and mix well;
[0077] The reaction flask was continuously evacuated to maintain a vacuum degree of 0.08 MPa, and the first heating reaction was carried out, heating to 150° C. for 10 min, and then naturally cooled for standby use;
[0078] (2) Add 148.0 mg NH4F and 100.0 mg NaOH into centrifuge tubes containing 7 ml and 3 ml methanol, respectively, and dissolve under ultrasonic conditions for later use;
[0079] The NH4F methanol solution and the NaOH methanol solution were quickly mixed and shaken to make them uniform, and then dropped into the solution obtained in (1). 3+ +Re 3+ ):n(Na + )=1:2.3,n(Fe 3+ +Re 3+ ):n(F - )=1:3.6; then carry out the second heating reaction, keep warm at 40℃ for 40min;
[0080] (3) introducing nitrogen into the solution obtained in (2) and performing a third heating reaction, heating the solution to 120° C. at a rate of 20° C. / min and maintaining the temperature for 10 min; during the temperature maintenance process, evacuating the solution until there are no bubbles in the solution;
[0081] (4) continuing to introduce nitrogen into the solution obtained in (3) and performing a fourth heating reaction, heating the solution from 120° C. to 305° C. at a rate of 12° C. / min and maintaining the temperature for 2 h, and then cooling the solution naturally for later use;
[0082] (5) Add 10 ml of anhydrous ethanol to the solution obtained in (4), centrifuge and wash the resulting precipitate with 4 ml of cyclohexane and 8 ml of ethanol, repeating this process three times; then place the precipitate in a vacuum drying oven at 60°C and dry it for 12 h; thus, powdered Fe 3+ Assisted synthesis of rare earth fluoride NaReF4 nanorods.
[0083] The Fe 3+ TEM image of NaReF4 nanorods synthesized by assisted synthesis Figure 1 As shown, the nanorod has a diameter of 25 nm, a length of 75 nm, and an aspect ratio of 3. Figure 2 This is the mapping image and EDS element content analysis of the nanorods. It can be seen that there is no Fe element in the nanorods.
[0084] Example 2
[0085] Catalyst (Fe 3+ ) assisted synthesis of rare earth fluoride NaReF4 nanorods preparation method:
[0086] (1) Add 305.0 mg ErCl3·6H2O and 108.0 mg FeCl3·6H2O to a reaction flask, and then add 6 ml OA and 15 ml OED and mix well;
[0087] The reaction flask was continuously evacuated to maintain a vacuum degree of 0.08 MPa, and the first heating reaction was carried out, heating to 130° C. for 10 min, and then naturally cooled for standby use;
[0088] (2) Add 111.0 mg NH4F and 140.0 mg NaOH into centrifuge tubes containing 5 ml and 5 ml methanol, respectively, and dissolve under ultrasonic conditions for later use;
[0089] The NH4F methanol solution and the NaOH methanol solution were quickly mixed and shaken to make them uniform, and then dropped into the solution obtained in (1). 3+ +Re 3+ ):n(Na + )=1:2.9,n(Fe 3+ +Re 3+ ):n(F -) =1:2.5; then carry out the second heating reaction, keep warm at 40°C for 20min;
[0090] (3) introducing nitrogen into the solution obtained in (2) and performing a third heating reaction, heating the solution to 120° C. at a rate of 20° C. / min and maintaining the temperature for 10 min; during the temperature maintenance process, evacuating the solution until there are no bubbles in the solution;
[0091] (4) continuing to introduce nitrogen into the solution obtained in (3) and performing a fourth heating reaction, heating the solution from 120° C. to 270° C. at a rate of 12° C. / min and maintaining the temperature for 2 h, and then cooling the solution naturally for later use;
[0092] (5) Add 10 ml of anhydrous ethanol to the solution obtained in (4), centrifuge and wash the resulting precipitate with 4 ml of cyclohexane and 8 ml of ethanol, repeating this process three times; then place the precipitate in a vacuum drying oven at 60°C and dry it for 12 h; thus, powdered Fe 3+ Assisted synthesis of rare earth fluoride NaReF4 nanorods.
[0093] The Fe 3+ TEM image of NaReF4 nanorods synthesized by assisted synthesis Figure 3 As shown, the nanorod has a diameter of 23 nm, a length of 47 nm, and an aspect ratio of 2.
[0094] Example 3
[0095] Catalyst (Fe 3+ ) assisted synthesis of rare earth fluoride NaReF4 nanorods preparation method:
[0096] (1) Add 76.0 mg ErCl3·6H2O and 243.0 mg FeCl3·6H2O to a reaction flask, and then add 12 ml OA and 15 ml OED and mix well.
[0097] The reaction flask was continuously evacuated to maintain a vacuum degree of 0.08 MPa, and the first heating reaction was carried out, heating to 130° C. for 10 min, and then naturally cooled for standby use;
[0098] (2) Add 148.0 mg NH4F and 100.0 mg NaOH into centrifuge tubes containing 7 ml and 3 ml methanol, respectively, and dissolve under ultrasonic conditions for later use;
[0099] The NH4F methanol solution and the NaOH methanol solution were quickly mixed and shaken to make them uniform, and then dropped into the solution obtained in (1). 3+ +Re 3+ ):n(Na + )=1:2.3,n(Fe 3+ +Re 3+ ):n(F - )=1:3.6; then carry out the second heating reaction, keep warm at 40℃ for 5min;
[0100] (3) introducing nitrogen into the solution obtained in (2) and performing a third heating reaction, heating the solution to 120° C. at a rate of 20° C. / min and maintaining the temperature for 10 min; during the temperature maintenance process, evacuating the solution until there are no bubbles in the solution;
[0101] (4) continuing to introduce nitrogen into the solution obtained in (3) and performing a fourth heating reaction, heating the solution from 120° C. to 320° C. at a rate of 20° C. / min and maintaining the temperature for 2 h, and then cooling the solution naturally for later use;
[0102] (5) Add 10 ml of anhydrous ethanol to the solution obtained in (4), centrifuge and wash the resulting precipitate with 4 ml of cyclohexane and 8 ml of ethanol, repeating this process three times; then place the precipitate in a vacuum drying oven at 60°C and dry it for 12 h; thus, powdered Fe 3+ Assisted synthesis of rare earth fluoride NaReF4 nanorods.
[0103] The Fe 3+ TEM image of NaReF4 nanorods synthesized by assisted synthesis Figure 4 As shown, the nanorod has a diameter of 13 nm, a length of 66 nm, and an aspect ratio of 5;
[0104] Example 4
[0105] Catalyst (Fe 3+ ) assisted synthesis of rare earth fluoride NaReF4 nanorods preparation method:
[0106] (1) Add 191.0 mg ErCl3·6H2O, 77.5 mg YbCl3·6H2O and 108.0 mg FeCl3·6H2O to a reaction flask, then add 12 ml OA and 15 ml OED and mix well;
[0107] The reaction flask was continuously evacuated to maintain a vacuum degree of 0.08 MPa, and the first heating reaction was carried out, heating to 130° C. for 10 min, and then naturally cooled for standby use;
[0108] (2) Add 148.0 mg NH4F and 100.0 mg NaOH into centrifuge tubes containing 7 ml and 3 ml methanol, respectively, and dissolve under ultrasonic conditions for later use;
[0109] The NH4F methanol solution and the NaOH methanol solution were quickly mixed and shaken to make them uniform, and then dropped into the solution obtained in (1). 3+ +Re 3+ ):n(Na + )=1:2.3,n(Fe 3+ +Re 3+ ):n(F- )=1:3.6; then carry out the second heating reaction, keep warm at 40℃ for 5min;
[0110] (3) introducing nitrogen into the solution obtained in (2) and performing a third heating reaction, heating the solution to 120° C. at a rate of 20° C. / min and maintaining the temperature for 10 min; during the temperature maintenance process, evacuating the solution until there are no bubbles in the solution;
[0111] (4) nitrogen was continuously introduced into the solution obtained in (3) and a fourth heating reaction was performed, the temperature was raised from 120° C. to 310° C. at a rate of 20° C. / min and kept at this temperature for 2.5 h, and then the temperature was naturally lowered for standby use;
[0112] (5) Add 10 ml of anhydrous ethanol to the solution obtained in (4), centrifuge and wash the resulting precipitate with 4 ml of cyclohexane and 8 ml of ethanol, repeating this process three times; then place the precipitate in a vacuum drying oven at 60°C and dry it for 12 h; thus, powdered Fe 3+ Assisted synthesis of rare earth fluoride NaReF4 nanorods.
[0113] The Fe 3+ The diameter of the assisted synthesized rare earth fluoride NaReF4 nanorods is 20nm, the length is 60nm, and the aspect ratio is 3.
[0114] Example 5
[0115] Catalyst (Fe 3+ ) assisted synthesis of rare earth fluoride NaReF4 nanorods preparation method:
[0116] (1) Add 114.0 mg ErCl3·6H2O, 77.5 mg YbCl3·6H2O, 56.0 mg TbCl3·6H2O and 108.0 mg FeCl3·6H2O to a reaction flask, and then add 12 ml OA and 15 ml OED and mix well.
[0117] The reaction flask was continuously evacuated to maintain a vacuum degree of 0.08 MPa, and the first heating reaction was carried out, heating to 130° C. for 10 min, and then naturally cooled for standby use;
[0118] (2) Add 130.0 mg NH4F and 120.0 mg NaOH into centrifuge tubes containing 5 ml and 5 ml methanol, respectively, and dissolve under ultrasonic conditions for later use;
[0119] The NH4F methanol solution and the NaOH methanol solution were quickly mixed and shaken to make them uniform, and then dropped into the solution obtained in (1). 3+ +Re 3+ ):n(Na + )=1:2.7,n(Fe3+ +Re 3+ ):n(F - )=1:3.2; then carry out the second heating reaction, keep warm at 40℃ for 30min;
[0120] (3) introducing nitrogen into the solution obtained in (2) and performing a third heating reaction, heating the solution to 120° C. at a rate of 20° C. / min and maintaining the temperature for 10 min; during the temperature maintenance process, evacuating the solution until there are no bubbles in the solution;
[0121] (4) continuing to introduce nitrogen into the solution obtained in (3) and performing a fourth heating reaction, heating the solution from 120° C. to 340° C. at a rate of 20° C. / min and maintaining the temperature for 1.5 h, and then cooling the solution naturally for later use;
[0122] (5) Add 10 ml of anhydrous ethanol to the solution obtained in (4), centrifuge and wash the resulting precipitate with 4 ml of cyclohexane and 8 ml of ethanol, repeating this process three times; then place the precipitate in a vacuum drying oven at 60°C and dry it for 12 h; thus, powdered Fe 3+ Assisted synthesis of rare earth fluoride NaReF4 nanorods.
[0123] The Fe 3+ The diameter of the assisted synthesized rare earth fluoride NaReF4 nanorods is 17nm, the length is 65nm, and the aspect ratio is 3.8.
[0124] Comparative Example 1
[0125] Compared with Example 1, the difference is that no catalyst is added.
[0126] Preparation method of rare earth fluoride NaReF4 nanorods:
[0127] (1) Add 267.0 mg of ErCl3·6H2O to the reaction flask, and then add 12 ml of OA and 15 ml of OED and mix well;
[0128] The reaction flask was continuously evacuated to maintain a vacuum degree of 0.08 MPa, and the first heating reaction was carried out, heating to 150° C. for 10 min, and then naturally cooled for standby use;
[0129] (2) Add 148.0 mg NH4F and 100.0 mg NaOH into centrifuge tubes containing 7 ml and 3 ml methanol, respectively, and dissolve under ultrasonic conditions for later use;
[0130] The NH4F methanol solution and the NaOH methanol solution were quickly mixed and shaken to be uniform, and then dropped into the solution obtained in (1), and a second heating reaction was performed, and the temperature was kept at 40°C for 40 minutes;
[0131] (3) introducing nitrogen into the solution obtained in (2) and performing a third heating reaction, heating the solution to 120° C. at a rate of 20° C. / min and maintaining the temperature for 10 min; during the temperature maintenance process, evacuating the solution until there are no bubbles in the solution;
[0132] (4) continuing to introduce nitrogen into the solution obtained in (3) and performing a fourth heating reaction, heating the solution from 120° C. to 305° C. at a rate of 12° C. / min and maintaining the temperature for 2 h, and then cooling the solution naturally for later use;
[0133] (5) Add 10 ml of anhydrous ethanol to the solution obtained in (4), centrifuge and wash the resulting precipitate with 4 ml of cyclohexane and 8 ml of ethanol, repeating this process three times; then place the precipitate in a vacuum drying oven at 60° C. and dry it for 12 h; thus, rare earth fluoride NaReF4 nanoparticles are obtained.
[0134] The rare earth fluoride NaReF4 prepared in this comparative example is irregular polygonal nanoparticles at the nanometer level, and the TEM image is as follows: Figure 5 shown.
[0135] When the rare earth fluoride NaReF4 is in the form of polygonal nanoparticles and is used in biomedical experiments, its cellular uptake rate is much lower than that of the nanorods synthesized in Example 1 under the same experimental conditions; when applied to polarized luminescence, its polarized luminescence properties are also much weaker than those of the nanorods prepared in Example 1 under the same experimental conditions.
[0136] Comparative Example 2
[0137] Compared with Example 1, the difference is that the amount of the catalyst substance accounts for 9.1% of the total amount of the rare earth compound and the catalyst substance.
[0138] (1) Add 382.0 mg ErCl3·6H2O and 27 mg FeCl3·6H2O to a reaction flask, then add 6 ml OA and 15 ml OED and mix well;
[0139] The reaction flask was continuously evacuated to maintain a vacuum degree of 0.08 MPa, and the first heating reaction was carried out, heating to 150° C. for 10 min, and then naturally cooled for standby use;
[0140] (2) Add 148.0 mg NH4F and 100.0 mg NaOH into centrifuge tubes containing 7 ml and 3 ml methanol, respectively, and dissolve under ultrasonic conditions for later use;
[0141] The NH4F methanol solution and the NaOH methanol solution were quickly mixed and shaken to be uniform, and then dropped into the solution obtained in (1), and a second heating reaction was performed, and the temperature was kept at 40°C for 40 minutes;
[0142] (3) introducing nitrogen into the solution obtained in (2) and performing a third heating reaction, heating the solution to 120° C. at a rate of 20° C. / min and maintaining the temperature for 10 min; during the temperature maintenance process, evacuating the solution until there are no bubbles in the solution;
[0143] (4) continuing to introduce nitrogen into the solution obtained in (3) and performing a fourth heating reaction, heating the solution from 120° C. to 305° C. at a rate of 12° C. / min and maintaining the temperature for 2 h, and then cooling the solution naturally for later use;
[0144] (5) Add 10 ml of anhydrous ethanol to the solution obtained in (4), centrifuge and wash the resulting precipitate with 4 ml of cyclohexane and 8 ml of ethanol, repeating this process three times; then place the precipitate in a vacuum drying oven at 60° C. and dry it for 12 h; thus, rare earth fluoride NaReF4 nanoparticles are obtained.
[0145] The rare earth fluoride NaReF4 prepared in this comparative example is a 24nm round particle, and the TEM image is as follows: Figure 6 shown.
[0146] Comparative Example 3
[0147] Compared with Example 1, the difference is that the catalyst is Fe powder.
[0148] The rare earth fluoride NaReF4 obtained in this comparative example is conventional nearly round nanoparticles, and a nanorod structure cannot be obtained.
[0149] In summary, the catalyst-assisted synthesis method for preparing rare earth fluoride NaReF4 nanorods of the present invention adjusts the morphology of rare earth fluoride NaReF4 into nanorods with uniform particle size, high aspect ratio and adjustable size by adding a catalyst to the raw material system.
[0150] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.
Claims
1. A method for preparing rare earth fluoride NaReF4 nanorods by catalyst-assisted synthesis, characterized in that: The preparation method comprises: (1) After mixing a rare earth compound, a catalyst, oleic acid, and 1-octadecene in a reaction container, the reaction container is continuously evacuated and a first heating reaction is performed; (2) dissolving the F source and the Na source in a solvent respectively and mixing them, then dropping them into the solution obtained in (1) and performing a second heating reaction; (3) introducing nitrogen gas into the solution obtained in (2) and performing a third heating reaction; (4) continuing to introduce nitrogen into the solution obtained in (3) and performing a fourth heating reaction; (5) The solution obtained in (4) is centrifuged, washed, and dried to obtain catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods.
2. The preparation method according to claim 1, characterized in that: The catalyst in (1) comprises one or more of a trivalent iron compound, a manganese-containing compound, a chromium-containing compound, and a ruthenium-containing compound.
3. The preparation method according to claim 1, characterized in that: In the above (1), the amount of the catalyst accounts for 10 to 95% of the total amount of the rare earth compound and the catalyst.
4. The preparation method according to claim 1, characterized in that: In (2), before the reaction, the ratio of the total amount of the catalyst and rare earth compounds in the solution to the amount of the Na source is 1:(1-5); the ratio of the total amount of the catalyst and rare earth compounds in the solution to the amount of the F source is:(2-10).
5. The preparation method according to claim 1, characterized in that: The vacuum degree of the first heating reaction in (1) is ≤0.08Mpa; the heating temperature is 100-180°C, and the heating and heat preservation time is 1-60min.
6. The preparation method according to claim 1, characterized in that: The heating temperature of the second heating reaction in (2) is 20 to 60° C., and the heating and heat preservation time is 1 to 60 minutes.
7. The preparation method according to claim 1, characterized in that: The heating temperature of the third heating reaction in (3) is 100-200°C, the heating and heat preservation time is 1-20min, and the heating rate is 1-20°C / min.
8. The preparation method according to claim 1, characterized in that: The heating temperature of the fourth heating reaction in (4) is 230-350°C, the heating and heat preservation time is 70-300min, and the heating rate is 1-20°C / min.
9. A catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods has a diameter of 8-45 nm, a length of 30-200 nm, and an aspect ratio of 1.2-20.
10. Application of the catalyst-assisted synthesis of rare earth fluoride NaReF4 nanorods according to claim 9 in the fields of anti-Stokes luminescence, polarization optics, environmental detection, optical imaging, biomedical diagnosis and treatment, etc.