Universal preparation method of amorphous rare earth-based oxide sub-nanowire

Abstract

The invention relates to the technical field of synthesis of new inorganic compound materials, and discloses a universal preparation method of an amorphous rare earth-based oxide sub-nanowire. The preparation method comprises the following steps: adding a rare earth salt and a template agent into a reaction system of a mixed solvent, fully stirring or ultrasonically dispersing uniformly to form a uniform solution, then transferring the uniform solution into a reaction kettle for solvothermal reaction, after the reaction is completed, washing the solution with a solvent, centrifuging for several times, and drying to obtain the rare earth-based composite material. And finally, the amorphous sub-nanowire material with uniform size and uniform rare earth element distribution is obtained. The preparation method for synthesizing the amorphous rare earth-based oxide sub-nanowire is simple and convenient, the raw materials are easy to obtain, the cost is low, the synthesis strategy has certain universality, and the preparation method can be expanded to rare earth elements covering all single components, multiple components or high-entropy components in a lanthanide series. Based on the characteristics of the amorphous rare earth-based oxide sub-nanowire, the amorphous rare earth-based oxide sub-nanowire shows huge application potential in the fields of energy storage and conversion.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of new material preparation of inorganic compounds, and particularly relates to a universal preparation method of amorphous rare earth-based oxide sub-nanowires. BACKGROUND

[0002] With the rapid development of science and technology, a new round of scientific and technological revolution and industrial change is accelerating the intelligentization, low-carbonization and convenience of people's production / life style. In the field of energy storage and conversion, most of the high-efficiency catalysts constructed are composite materials mainly composed of transition metals / alkali metals. In contrast, rare earth elements, known as "industrial vitamins", have a special electronic configuration (4f n-1 5d 0-1 6s 2 , n = 1 ~ 15), the 4f electrons in the inner layer are shielded by the 6s and 5d electrons in the outer layer, and the localization and incomplete filling of the 4f electrons endow rare earth materials with rich electronic energy level structure, variable coordination number and other characteristics, showing great application potential in the field of energy storage and conversion.

[0003] Due to the near 100% atomic exposure rate and the unsaturated coordination of surface atoms of sub-nanowire materials (diameter size ~ 1 nm), high surface energy and electronic structure distortion are caused, which helps to improve the intrinsic catalytic activity of the material. Compared with crystalline materials, the short-range ordered and long-range disordered atomic structure arrangement of amorphous materials endows them with higher surface active site concentration, wider band gap adjustment range and more abundant structure tunability. Therefore, the electronic structure regulation of rare earth-based oxide sub-nanometer materials under the guidance of amorphization strategy is an effective way to realize the efficient utilization of rare earth elements.

[0004] The application utilizes the unique electronic structure of rare earth elements to develop high-efficiency catalyst materials, synthesizes single-component and multi-component amorphous rare earth-based oxide sub-nanowire materials by adopting ligand confinement strategy, and applies them to the field of energy storage and conversion. The application not only meets the diversified demand of the national "double carbon" strategy for new energy storage / conversion, but also provides technical support for promoting the high-value-added application of China's rich rare earth resources, and has important practical application value. SUMMARY

[0005] The application provides a universal preparation method of amorphous rare earth-based oxide sub-nanowires.

[0006] To solve the above technical problems, the application adopts the following technical scheme:

[0007] The application provides a universal preparation method of amorphous rare earth-based oxide sub-nanowires, which specifically comprises the following steps:

[0008] (1) a certain amount of template agent is weighed and placed in a glass beaker at room temperature;

[0009] (2) the rare earth salt is dissolved in an ethanol solution to prepare a rare earth salt dispersion solution with a certain concentration, and is added to step (1) and stirred sufficiently;

[0010] (3) a certain volume of surfactant is further added to step (2) to obtain a uniformly dispersed solution;

[0011] (4) then, the reaction solution in step (3) is transferred to a polytetrafluoroethylene-lined reaction kettle for heating reaction, and the reaction kettle is cooled to room temperature in an oven after reaction;

[0012] (5) the supernatant in step (4) is filtered, the obtained precipitate is washed with a solvent, and then vacuum dried to obtain the amorphous rare earth-based oxide sub-nanowire material of the application.

[0013] (6) further, the template agent in step (1) can be selected from phosphotungstic acid, silicotungstic acid and phosphomolybdic acid, and the amount is preferably 0.01-1.0 mmol / L;

[0014] (7) further, the rare earth element in step (2) includes any one or several of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Ey, Yb, Lu, Sc and Y;

[0015] (8) Further, the rare earth salt species in step (2) includes one or more of nitrate, chloride, acetylacetone or sulfate, preferably in an amount of 0.01-2 mmol / L;

[0016] (9) Further, the surfactant in step (3) can be selected from one or more of octadecylamine, hexadecylamine, oleylamine, oleic acid, dodecanethiol, and the surfactant is used in an amount of 1-20 mL;

[0017] (10) Further, the temperature for the heating reaction in step (4) is 100-200°C, and the holding time is 1-24 h;

[0018] (11) Further, the solvent in step (5) is one or more of cyclohexane, acetone, chloroform, dichloroethane and ethanol;

[0019] (12) In another aspect, the present application also provides the performance of the above-mentioned amorphous rare earth-based oxide sub-nanowires in electrochemical tests (sodium-sulfur battery system). BRIEF DESCRIPTION OF DRAWINGS

[0020] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings:

[0021] Figure 1 X-ray diffraction pattern of the amorphous cerium molybdate sub-nanowire material prepared in Example 1;

[0022] Figure 2 X-ray photoelectron spectroscopy of Ce and Mo in the amorphous cerium molybdate sub-nanowire material prepared in Example 1;

[0023] Figure 3 Transmission electron microscope image of the amorphous cerium molybdate sub-nanowire material prepared in Example 1;

[0024] Figure 4 Spherical aberration electron microscope and energy spectrum image of the amorphous cerium molybdate sub-nanowire material prepared in Example 1;

[0025] Figure 5 Transmission electron microscope images of the amorphous cerium molybdate sub-nanowire material prepared in Example 1 at different reaction times;

[0026] Figure 6 Transmission electron microscope images of different amorphous rare earth-based oxide sub-nanowire samples prepared in Examples 1-6;

[0027] Figure 7 Rate performance chart of the amorphous cerium molybdate sub-nanowire material prepared in Example 1 as a sodium-sulfur battery sulfur positive electrode catalyst at different current densities;

[0028] Figure 8 Figure 1 shows the long cycle performance of the amorphous cerium molybdate sub-nanowire material prepared in Example 1 as a sulfur positive electrode catalyst for sodium-sulfur batteries; DETAILED DESCRIPTION

[0029] Next, the technical solutions involved in the specific embodiments of the present application will be described clearly and in detail according to the specific embodiments of the present application. It should be noted that the embodiments described herein are only a part of the embodiments of the present application, not all. Based on the embodiments covered by the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the protection scope of the present application.

[0030] As an aspect of the present application, a universal preparation method of amorphous rare earth-based oxide sub-nanowires includes the following steps:

[0031] (1) A certain amount of rare earth element salt is added to anhydrous ethanol, and ultrasonic treatment is performed for 5-10 min until a uniform and clear solution is obtained;

[0032] (2) A certain amount of template agent is weighed and transferred to a clean beaker. Then, the solution prepared in step (1) is slowly added to the beaker, and appropriate stirring is maintained during the addition to ensure uniform mixing of the solution. After the solution is completely added, the magnetic stirrer or other suitable stirring device is used to continue stirring the mixed system for 5-10 min to ensure that the template agent and the solution obtained in step (1) are in sufficient contact and uniform interaction;

[0033] (3) A certain volume of surfactant is added to the system obtained in step (2), and stirring is continued for 10-20 min;

[0034] (4) The homogeneous solution in step (3) is transferred to a polytetrafluoroethylene-lined stainless steel autoclave, heated to a certain temperature, and kept for a period of time, and then the reaction kettle is naturally cooled with the oven;

[0035] (5) Further, when the reaction product of step (4) is subjected to centrifugation, the rotation speed is set to 6000-12000 rpm.

[0036] (6) The obtained precipitate is washed several times with organic reagent and ethanol to obtain the amorphous rare earth-based oxide sub-nanowires.

[0037] Example 1

[0038] (1) A certain amount of Ce(NO3)3·6H2O is weighed and prepared into a 0.05 mmol / L solution, and ultrasonic treatment is performed for 10 min to ensure complete dissolution;

[0039] (2) Accurately weigh 54.7 mg of phosphomolybdic acid and place it in a clean glass beaker. Add 2 mL of the solution from step (1) to it and stir for 10 min to form a homogeneous solution. Then add 5 mL of oleylamine and stir for 10 min to mix it thoroughly.

[0040] (3) Transfer the homogeneous solution from step (2) to a stainless steel reactor lined with polytetrafluoroethylene, place it in a reaction oven, heat it to 120°C, react it at this temperature for 2 hours, and finally cool it to room temperature with the oven.

[0041] (4) The product obtained in step (3) is washed and centrifuged several times with cyclohexane and ethanol to obtain amorphous cerium molybdate subnanowire material.

[0042] The X-ray diffraction pattern of the obtained material is attached. Figure 1 As shown, the spectrum shows no diffraction peaks, exhibiting a typical amorphous structure; the X-ray photoelectron spectra of Ce and Mo in the material are attached. Figure 2 As shown, Ce in the material mainly exhibits a +3 valence, and Mo mainly exhibits a +6 valence; transmission electron microscopy images of the material are attached. Figure 3 , 4 As shown, the nanowires have a diameter of approximately 1.3-1.6 nm, exhibit a typical disordered atomic structure, and show uniform distribution of Ce, Mo, and O elements. Transmission electron microscopy images of the material at different reaction times are attached. Figure 5 As shown, the material gradually grows from inorganic crystal nuclei of about 1 nm into a small number of worm-like structures, and then gradually grows into the target product of sub-nanowires; transmission electron microscope images of different materials are attached. Figure 6 As shown, all exhibit ultrafine nanowire morphology; the rate performance and long-cycle performance of the material as a sulfur cathode catalyst in sodium-sulfur batteries are shown in the attached figures. Figure 7 , 8 As shown, under different current densities (1C = 1672 mA g) -1 All exhibit high specific capacity, and can stably cycle for more than 1,000 times even at high current density, with a coulombic efficiency close to 100%, demonstrating excellent energy storage characteristics.

[0043] Example 2

[0044] (1) Weigh a certain amount of La(NO3)3·6H2O to prepare a 0.05mmol / L solution, and sonicate for 10min to fully dissolve it;

[0045] (2) Accurately weigh 54.7 mg of phosphomolybdic acid and place it in a clean glass beaker. Add 2 mL of the solution from step (1) to it and stir for 10 min to form a homogeneous solution. Then add 5 mL of oleylamine and stir for 10 min to mix it thoroughly.

[0046] (3) The homogeneous solution of step (2) is transferred to a stainless steel autoclave with a polytetrafluoroethylene liner, placed in a reaction oven, heated to 120°C, reacted at this temperature for 2h, and finally reduced to room temperature with the oven;

[0047] (4) The product obtained in step (3) is washed several times by centrifugation using cyclohexane and ethanol, and then an amorphous lanthanum molybdate sub-nanowire material is obtained.

[0048] The transmission electron microscope image of the material is shown in the accompanying Figure 5 and presents a superfine nanowire morphology.

[0049] Example 3

[0050] (1) A certain amount of Pr(NO3)3·6H2O is weighed and configured into a 0.05 mmol / L solution, and ultrasonic treatment is performed for 10 min to make it fully dissolved;

[0051] (2) 54.7 mg of phosphomolybdic acid is accurately weighed into a clean glass beaker, 2 mL of the solution of step (1) is added thereto, stirred for 10 min to form a homogeneous solution, and then 5 mL of oleylamine is added, stirred for 10 min to make it fully mixed;

[0052] (3) The homogeneous solution of step (2) is transferred to a stainless steel autoclave with a polytetrafluoroethylene liner, placed in a reaction oven, heated to 130°C, reacted at this temperature for 6h, and finally reduced to room temperature with the oven;

[0053] (4) The product obtained in step (3) is washed several times by centrifugation using cyclohexane and ethanol, and then an amorphous lanthanum molybdate sub-nanowire material is obtained.

[0054] The transmission electron microscope image of the material is shown in the accompanying Figure 5 and presents a superfine nanowire morphology.

[0055] Example 4

[0056] (1) A certain amount of Nd(NO3)3·xH2O is weighed and configured into a 0.05 mmol / L solution, and ultrasonic treatment is performed for 10 min to make it fully dissolved;

[0057] (2) 54.7 mg of phosphomolybdic acid is accurately weighed into a clean glass beaker, 2 mL of the solution of step (1) is added thereto, stirred for 10 min to form a homogeneous solution, and then 5 mL of oleylamine is added, stirred for 10 min to make it fully mixed;

[0058] (3) The homogeneous solution of step (2) is transferred to a stainless steel autoclave with a polytetrafluoroethylene liner, placed in a reaction oven, heated to 130°C, reacted at this temperature for 6h, and finally reduced to room temperature with the oven;

[0059] (4) The product obtained in step (3) is washed several times with cyclohexane and ethanol, and then centrifuged, to obtain the amorphous neodymium molybdate sub-nanowire material.

[0060] The transmission electron microscope image of the material is shown in the accompanying Figure 5 figure, and presents a superfine nanowire morphology.

[0061] Example 5

[0062] (1) A certain amount of Sm(NO3)3·6H2O is weighed and configured into a 0.05 mmol / L solution, and is ultrasonically dissolved for 10 min;

[0063] (2) 54.7 mg of phosphomolybdic acid is accurately weighed into a clean glass beaker, 2 mL of the solution in step (1) is added, stirred for 10 min to form a uniform solution, and then 6 mL of oleylamine is added, stirred for 10 min, and fully mixed;

[0064] (3) The homogeneous solution in step (2) is transferred to a polytetrafluoroethylene-lined stainless steel reaction kettle, placed in a reaction oven, heated to 140°C, reacted at this temperature for 6 h, and finally reduced to room temperature with the oven;

[0065] (4) The product obtained in step (3) is washed several times with cyclohexane and ethanol, and then centrifuged, to obtain the amorphous neodymium molybdate sub-nanowire material.

[0066] The transmission electron microscope image of the material is shown in the accompanying Figure 5 figure, and presents a superfine nanowire morphology.

[0067] Example 6

[0068] (1) A certain amount of Eu(NO3)3·6H2O is weighed and configured into a 0.05 mmol / L solution, and is ultrasonically dissolved for 10 min;

[0069] (2) 54.7 mg of phosphomolybdic acid is accurately weighed into a clean glass beaker, 2 mL of the solution in step (1) is added, stirred for 10 min to form a uniform solution, and then 6 mL of oleylamine is added, stirred for 10 min, and fully mixed;

[0070] (3) The homogeneous solution in step (2) is transferred to a polytetrafluoroethylene-lined stainless steel reaction kettle, placed in a reaction oven, heated to 160°C, reacted at this temperature for 8 h, and finally reduced to room temperature with the oven;

[0071] (4) The product obtained in step (3) is washed several times with cyclohexane and ethanol, and then centrifuged, to obtain the amorphous neodymium molybdate sub-nanowire material.

[0072] The transmission electron microscope image of the material is shown in Figure 1 1 and exhibits a super-fine nanowire morphology. Figure 5 The transmission electron microscope image of the material is shown in Figure 1 1 and exhibits a super-fine nanowire morphology.

Claims

1. A universal preparation method for amorphous rare earth-based oxide subnanowires, characterized in that: Includes the following steps: (1) Weigh a certain mass of template agent at room temperature and place it in a glass beaker; (2) Dissolve the rare earth salt in an ethanol solution to prepare a rare earth salt dispersion of a certain concentration, and add it to step (1) and stir thoroughly. (3) Add a certain volume of surfactant to step (2) to obtain a uniformly dispersed solution; (4) The reaction solution in step (3) is then transferred to a polytetrafluoroethylene-lined reactor for heating and reaction, and then cooled to room temperature in an oven after the reaction. (5) Filter out the supernatant in step (4), wash the obtained precipitate with solvent, and dry it under vacuum to obtain the amorphous rare earth-based oxide subnanowire material of the present invention.

2. The universal preparation method for amorphous rare earth-based oxide subnanowires according to claim 1, characterized in that: The template agent mentioned in step (1) can be selected from phosphotungstic acid, silicotungstic acid, or phosphomolybdic acid, and the amount of the template agent used is 0.01-1.0 mol / L.

3. The universal preparation method for amorphous rare earth-based oxide subnanowires according to claim 1, characterized in that: The rare earth salt mentioned in step (2) is any one or more elements selected from La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Ey, Yb, Lu, Sc, and Y.

4. The universal preparation method for amorphous rare earth-based oxide subnanowires according to claim 1, characterized in that: The rare earth salt in step (2) includes one or more of nitrates, chlorides, acetylacetones or sulfates, and the concentration of the rare earth salt in the solution is 0.01 to 2 mmol / L.

5. The universal preparation method of amorphous rare earth-based oxide subnanowires according to claim 1, characterized in that: The surfactant used in step (3) can be one or more of octadecylamine, hexadecylamine, oleylamine, oleic acid, and dodecanethiol, and the amount of surfactant used is 1 to 20 mL.

6. The universal preparation method for amorphous rare earth-based oxide subnanowires according to claim 1, characterized in that: The heating reaction in step (4) is carried out at a temperature of 100-200°C for 1-24 hours.

7. The universal preparation method for amorphous rare earth-based oxide subnanowires according to claim 1, characterized in that: The solvent in step (5) is one or more of cyclohexane, acetone, chloroform, dichloroethane, and ethanol.

8. The application of amorphous rare earth-based oxide subnanowires prepared by the method described in claim 1 as a catalyst material in energy storage and conversion.

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