CN102220641B - Synthesis method of monoclinic crystal phase rare-earth iso-oxy-sulfur superfine nanowire and wire-based superstructure - Google Patents

Abstract

The invention discloses a monoclinic phase rare earth isosulfur Ln₂OS₂(Ln=Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb) Synthesis of ultrafine nanowires and nanowire-based superstructures in fatty acids, aliphatic amines and octadecyl In a mixed solvent composed of alkene, heat the rare earth metal nitrate solid and thiourea solid to 180-200 The solid-liquid phase reaction is carried out at ℃, and the target product is obtained after the reaction product is separated. The method of the invention adopts a solid-liquid phase chemical reaction route, replaces organic metal compounds with rare earth nitrate solids, and efficiently and controllably synthesizes a series of rare earth isosulfur ultrafine nanowires and nanowire-based superstructures. The synthesis method of the invention has simple and safe operation process, has universal applicability, and can realize large-scale preparation of the product.

Description

Synthesis method of monoclinic rare earth isosulfur ultrafine nanowires and wire-based superstructures

technical field

The present invention relates to a synthesis method of rare earth isosulfur nanomaterials, in particular to a novel monoclinic phase rare earth isosulfur (Ln ₂ OS ₂ , Ln = Y, La, Ce, Pr, Nd, Sm, Eu , Gd, Dy, Ho, Er, Yb) ultrafine nanowires and nanowire-based superstructures.

Background technique

Size and dimension are two important geometric structure parameters that affect the physical and chemical properties of nanomaterials. Among various nanostructures, 1D nanowires (cylindrical structures with a diameter less than 100 nanometers) have different electronic density of states than 0D, 2D and 3D nanostructures due to their radial height confinement and axial preferential growth. The unique physical and chemical properties different from other nanostructures have potential application prospects in the fields of electronics, catalysis, sensing and environmental degradation.

In recent years, the synthesis of ultrafine nanowires and nanowire-based superstructures with diameters less than 10 nm has attracted the interest and attention of many scientists. This is because as the diameter of the nanowire decreases sharply, the proportion of surface atoms increases sharply, and the electronic density of states changes significantly, and the surface effect and quantum effect will become more significant, which is conducive to the adsorption of foreign species and the interaction of electrons between nanowires. Coupled with communication, enhanced or new catalytic, sensing and optoelectronic properties are possible.

Usually, the synthesis of nanowires mainly adopts template method, liquid-liquid interface synthesis method, chemical vapor deposition (CVD) and liquid phase catalytic growth method. However, it is difficult to synthesize ultrafine nanowires with a diameter of less than 10 nanometers by the above method. Therefore, it is of great significance to explore new, reproducible, and universal methods to synthesize ultrafine nanowires and nanowire-based superstructures, and to study their physical and chemical properties.

As an important class of functional materials, rare earth isosulfur compounds have excellent fluorescence properties and have important commercial applications in the fields of radiation intensifying screens (RIS), computed tomography (CT), oxygen storage, and radiation detection in medical imaging. value. According to the different ratio of oxygen and sulfur, rare earth isooxysulfur compounds can be divided into two categories. One is orthorhombic Ln ₂ O ₂ S (Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb), and the other is monoclinic Ln ₂ OS ₂ . At present, although there are reports of nanostructures of rare earth isosulfur compounds, such as nanoparticles, nanoplates, superlattices assembled by nanoplates, nanorods, nanowires, etc., the obtained products are mainly in the orthorhombic phase. Ln ₂ O ₂ S. To the best of our knowledge, Ln ₂ OS ₂ nanostructures in the monoclinic phase have not been efficiently synthesized . The reason may be that the ionic radii of O and S are different. Rare earth ions have a strong affinity for O, but a relatively weak affinity for S. It is easy to obtain Ln ₂ O ₃ or Ln ₂ O ₂ S, it is difficult to obtain Ln ₂ OS ₂ . Compared with Ln ₂ O ₂ S, the proportion of S atoms in Ln ₂ OS ₂ increases, resulting in a sharp decrease in its lattice symmetry. According to Landau's symmetry breaking theory, Ln ₂ OS ₂ may have different physical and chemical properties from Ln ₂ O ₂ S.

In the present invention, rare earth nitrate (Ln(NO ₃ ) ₃ ·xH ₂ O and thiourea solids are heat-treated in solution, and 12 kinds of monoclinic phase rare earth oxysulfur Ln ₂ are controllably synthesized under relatively mild conditions. OS ₂ (Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb) ultrafine nanowires and nanowire-based superstructures. Ln ₂ OS ₂ superstructures in monoclinic phase Thin nanowires and nanowire-based superstructures can emit strong white light under near-ultraviolet light excitation, and can be used as ideal solid-state light source replacement materials in the field of future lighting technology.

Contents of the invention

_The object of _the present invention is to provide an ultrafine nano The controllable synthesis method of wire and nanowire-based superstructure, using the solid-liquid phase chemical reaction route, separates the nucleation and growth of _Ln2OS2 , with the aid of structure-directed reagents, by controlling the growth environment and _growth kinetics, Obtain monoclinic phase Ln ₂ OS ₂ ultra-fine nanowires and nanowire-based superstructures, and develop a new class of solid light source materials that emit white light.

The technical scheme that the present invention adopts is as follows:

A method for synthesizing monoclinic phase rare earth isosulfur ultrafine nanowires and nanowire-based superstructures, characterized in that: in a mixed solvent composed of fatty acid, fatty amine and octadecene, the rare earth metal nitrate solid Heating with thiourea solid to 180-200°C for solid-liquid phase reaction, the reaction product is separated to obtain the target product;

The chemical formula of the rare earth isosulfur is Ln ₂ OS ₂ , wherein Ln=Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er or Yb.

Described method specifically comprises the following steps:

1) Weigh a certain amount of rare earth metal nitrate solids and thiourea solids, and add them into a clean and dry reaction kettle lined with polytetrafluoroethylene;

2) Add an appropriate amount of fatty acid, fatty amine and octadecene, seal the reactor, heat it directly or place the reactor in an oven, raise the temperature to 180-200°C at a certain heating rate, and keep at this temperature for 10 -60 hours, naturally drop to room temperature;

3) The product obtained in step 2) is precipitated, centrifuged, washed, and vacuum-dried at room temperature to prepare monoclinic phase rare earth oxysulfur ultrafine nanowires and nanowire-based superstructures.

The molecular formula of the rare earth metal nitrate is Ln(NO ₃ ) ₃ ·xH ₂ O, wherein the rare earth metal element Ln is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er or Yb , x is an integer from 0 to 6.

The fatty acid is C6-C22 straight-chain fatty acid, preferably C8-C18 straight-chain fatty acid; the fatty amine is C6-C22 straight-chain primary aliphatic amine, preferably C8-C16 straight-chain primary aliphatic amine.

As a reaction raw material, the ratio of the rare earth metal nitrate solid, thiourea solid, fatty acid, fatty amine and octadecene can be selected as follows: the rare earth metal nitrate solid is 0.2-6.0 grams, the sulfur 0.1-4.50 grams of urea solid, the amount of fatty acid, fatty amine and octadecene in the mixed solvent is 2-10 mL, 2-10 mL and 5-20 mL respectively.

The solid-liquid phase reaction temperature of the method of the present invention is 180°C-200°C; the reaction time is 10-60 hours, preferably 20-30 hours, most preferably 24 hours. In step 2, the heating rate is 3°C-8°C per minute.

In step 3), first disperse the product obtained in step 2) with n-heptane, then add absolute ethanol to make it settle, and finally centrifuge, wash with n-heptane/absolute ethanol mixed solvent for 3-5 times, and The final product obtained was vacuum dried at 60 °C for 4 hours for analysis and characterization.

The dried product was collected, and its composition and phase were tested by X-Ray powder diffractometer (XRD); its morphology was analyzed by transmission electron microscope (TEM); and its morphology was analyzed by selected area electron diffraction (SAED) and high resolution electron microscope (HRTEM). Analyze its crystallization.

According to the test and analysis, rare earth isosulfur (Ln ₂ OS ₂ , Ln=Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb) ultrafine nanowires and nanowire-based ultrafine The structure is monoclinic phase, with a regular geometric structure (linear, parallel in two-dimensional space to form a sheet structure, three-dimensional space sheet structure will spontaneously organize into a layered structure or curled into a tubular structure), in which nano The length of the line is several hundred nm, the diameter is about 2-3 nm, which is close to the size of a single unit cell, and the aspect ratio is about 50-500.

Optical tests show that the monoclinic phase Ln ₂ OS ₂ ultrafine nanowires and nanowire-based superstructures prepared by the method of the present invention can emit strong white light when excited by near-ultraviolet light.

The present invention has the advantages of adopting a simple solid-liquid phase chemical route, replacing expensive organometallic compounds with cheap rare earth nitrate solids, replacing commonly used toxic solvents with environmentally friendly solvents, and passing through By controlling the reaction parameters, a series of rare earth isosulfur oxides (Ln ₂ OS ₂ , Ln=Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb) were synthesized efficiently and controllably. Nanowires and nanowire-based superstructures. The ultra-fine nanowire and the nanowire-based superstructure material prepared by the method of the present invention have good luminous properties, can emit strong white light under near-ultraviolet light excitation, and can be used as candidate materials for solid light sources for future lighting. In addition, the synthesis method of the present invention is simple, safe, and universally applicable, and can produce products on a large scale, laying a solid foundation for the application of this type of material.

The large-scale controllable synthesis of monoclinic phase rare earth oxysulfide (Ln ₂ OS ₂ ) ultrafine nanowires and nanowire-based superstructures of the present invention not only expands the composition of the entire ultrafine nanowire family, but also contributes to basic scientific research It is of great value, and has great strategic significance for the rational and efficient development and application of rare earth resources in China.

Description of drawings

Figure 1 is the X-Ray powder diffraction pattern of the Y ₂ OS ₂ ultrafine nanowires and their superstructures synthesized according to Example 1. The figure shows 12 obvious diffraction peaks, which can be attributed to the monoclinic phase Y ₂ OS ₂ (011), (111), (21-2), (021), (211), (121), (300), (22-1), (12-1), (131), (21- 3) and (322) crystal plane diffraction.

Figure 2b and Figure 2a are TEM images of Y ₂ OS ₂ ultrafine nanowires and their superstructures synthesized according to Example 1, confirming that the morphology of the obtained product is a one-dimensional (1D) linear structure with a length of several hundred nm , the diameter is about 2-3 nm, and the aspect ratio is about 50-500. Under certain conditions, the ultra-fine nanowire structure spontaneously organizes to form a 2D sheet structure or a 3D layered structure.

Figure 2c is the HRTEM image of the Y ₂ OS ₂ ultrafine nanowires synthesized according to Example 1, which further confirms that the obtained Y ₂ OS ₂ has a one-dimensional linear structure; the crystallization properties and growth direction of the nanowires can be further observed by HRTEM, The interplanar spacing of a single nanowire is measured to be 0.29 nm, which corresponds to the (211) crystal plane of the monoclinic phase Y ₂ OS ₂ . The interplanar spacing of the thinner part of the nanowire is 0.27 nm, which corresponds to the (300) crystal plane of Y ₂ OS ₂ .

Figure 2d is the SAED of the Y ₂ OS ₂ ultrafine nanowires synthesized according to Example 1. According to calculation, the crystal planes corresponding to the diffraction rings are (011), (300) and (322).

Figure 3a, Figure 4a, Figure 5a, Figure 6a, Figure 7a are Gd ₂ OS ₂ , Dy ₂ OS ₂ , Ho ₂ OS ₂ , Er ₂ OS ₂ and X-Ray powder diffraction pattern of Yb ₂ OS ₂ ultrafine nanowires, confirming that the synthesized Gd ₂ OS ₂ , Dy ₂ OS ₂ , Ho ₂ OS ₂ , Er ₂ OS ₂ and Yb ₂ OS ₂ nanowires have high purity and crystallization Better, and all are monoclinic crystal phase structures.

Figure 3b, Figure 4b, Figure 5b, Figure 6b, Figure 7b are Gd ₂ OS ₂ , Dy ₂ OS ₂ , Ho ₂ OS ₂ , Er ₂ OS ₂ and TEM image of Yb ₂ OS ₂ ultra-fine nanowires. The morphology of the obtained products is one-dimensional linear structure, with a length of several hundred nm, a diameter of about 2-3 nm, and an aspect ratio of about 50-500, arranged in parallel into a 2D sheet structure.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. The protection scope of the present invention is not limited by the specific embodiments, but by the claims.

Example 1

In a clean and dry reaction kettle with polytetrafluoroethylene lining (volume 50 mL), add 0.20~6.0g Y(NO ₃ ) ₃ 6 H ₂ O solid, 0.10~4.50g thiourea Solid, 2-10 mL oleic acid (Aldrich, 90%), 2-10 mL dodecylamine (Alfa Aesar, 98%), and 5-20 mL octadecene (Alfa Aesar, 90%), sealed reaction kettle The mixture was transferred to an oven and raised from room temperature to 180 °C at a rate of 4 °C/min. After 24 h of reaction, the temperature was naturally cooled to room temperature. To obtain a light brown jelly, add n-heptane, heat slightly, then add ethanol to precipitate, and centrifuge to separate the solid. Then the initial product was washed with a mixed solvent of n-heptane/absolute ethanol (volume ratio: 2/1), and a precipitate was obtained after centrifugation. Washing was repeated 3-5 times to obtain a light yellow-green solid product, and finally the washed product was vacuum-dried at 60°C for 4 h.

The dried product was collected, and its composition and phase were tested by X-Ray powder diffractometer (XRD). The results showed that the obtained product was pure monoclinic Y ₂ OS ₂ (Figure 1). Observation and analysis of its morphology and structure with transmission electron microscopy (TEM ₎ , selected area electron diffraction (SAED) and high resolution electron microscopy (HRTEM) ( _Fig . The linear structure has a length of several hundred nm, a diameter of about 2-3 nm, and an aspect ratio of about 50-500, and is arranged in parallel to form a 2D sheet-like structure.

Example 2

In a clean and dry reaction kettle with polytetrafluoroethylene lining (volume 50 mL), add 0.2-6.0 g Gd(NO ₃ ) ₃ 6 H ₂ O solid, 0.10-4.50 g thiourea solid , 2-10 mL oleic acid, 2-10 mL dodecylamine and 5-20 mL octadecene, sealed the reaction kettle and transferred it to an oven, and raised it from room temperature to 180 °C at a rate of 4 °C/min. After 24 h of reaction, the temperature was naturally cooled to room temperature, and a light brown jelly was obtained. Add n-heptane, heat slightly, then add ethanol, and centrifuge to separate the solid. Then, the obtained primary product was washed with a mixed solvent of n-heptane/absolute ethanol (volume ratio: 2/1), and a precipitate was obtained after centrifugation. Washing was repeated 3-5 times to obtain a light yellow-green solid product, and finally the washed product was vacuum-dried at 60°C for 4 h. .

The dried product was collected, and its composition and phase were tested by X-Ray powder diffractometer (XRD), which showed that the obtained product was pure Gd ₂ OS ₂ with monoclinic crystal structure (Fig. 3a). Its morphology and structure were observed with transmission electron microscopy (TEM) (Fig. 3b). The results show that the morphology of the obtained Gd ₂ OS ₂ is a one-dimensional linear structure with a length of several hundred nm, a diameter of about 2-3 nm, and an aspect ratio of about 50-500, which are arranged in parallel into a 2D sheet-like structure.

Example 3

In a clean and dry reaction kettle with polytetrafluoroethylene lining (volume 50 mL), add 0.2-6.0 g Dy(NO ₃ ) ₃ 6 H ₂ O solid, 0.10-4.50 g thiourea solid , 2-10 mL oleic acid, 2-10 mL dodecylamine and 5-20 mL octadecene, sealed the reaction kettle and transferred it to an oven, and raised it from room temperature to 200 °C at a rate of 4 °C/min, After 24 h of reaction, the temperature was naturally cooled to room temperature. A light brown gum was obtained. Add n-heptane, heat slightly, then add ethanol, and centrifuge to separate the solid. Then, the obtained product was washed with a mixed solvent of n-heptane/absolute ethanol (volume ratio: 2/1), and a precipitate was obtained after centrifugation. The washing operation was repeated 3-5 times to obtain a light yellow-green solid product, and finally the washed product was vacuum-dried at 60 °C for 4 h.

The dried product was collected, and its composition and phase were tested by X-Ray powder diffractometer (XRD). The results showed that the obtained product was Dy ₂ OS ₂ with a pure monoclinic crystal phase structure (Fig. 4a). The morphology and structure of the obtained Dy ₂ OS ₂ were observed with a transmission electron microscope (TEM) (Fig. 4b). The diameter ratio is about 50-500, and they are arranged in parallel to form a 2D sheet structure.

Example 4

In a clean and dry reaction kettle with polytetrafluoroethylene lining (volume 50 mL), add 0.2-6.0 g Ho(NO ₃ ) ₃ 6 H ₂ O solid, 0.10-4.50 g thiourea solid , 2-10 mL oleic acid, 2-10 mL dodecylamine and 5-20 mL octadecene, seal the reaction kettle and transfer it to an oven, and raise it from room temperature to 180 °C at a rate of 6 °C/min, After 24 h of reaction, the temperature was naturally cooled to room temperature. To obtain a light brown jelly, add n-heptane, heat slightly, then add ethanol, and centrifuge to separate the solid. Then, the obtained primary product was washed with a mixed solvent of n-heptane/absolute ethanol (volume ratio: 2/1), and a precipitate was obtained after centrifugation. Washing was repeated 3-5 times to obtain a light yellow-green solid product, and finally the washed product was vacuum-dried at 60 °C for 4 h.

The dried product was collected, and its composition and phase were tested by X-Ray powder diffractometer (XRD). The results showed that the obtained product was Ho ₂ OS ₂ with a pure monoclinic crystal phase structure (Fig. 5a). The morphology and structure were observed with a transmission electron microscope (TEM) (Fig. 5b). The results showed that the obtained Ho ₂ OS ₂ had a one-dimensional linear structure with a length of several hundred nm and a diameter of about 2-3 nm. The aspect ratio is about 50-500, and they are arranged in parallel into a 2D sheet-like structure.

Example 5

In a clean and dry reaction kettle with polytetrafluoroethylene lining (volume 50 mL), add 0.20~6.0 g Er(NO ₃ ) ₃ 6 H ₂ O solid, 0.10~4.50 g thiourea solid , 2-10 mL oleic acid, 2-10 mL dodecylamine and 5-20 mL octadecene, sealed the reaction kettle and transferred it to an oven, and raised it from room temperature to 185 °C at a rate of 4 °C/min. After 24 h of reaction, the temperature was naturally cooled to room temperature. A light brown gum was obtained. Add n-heptane, heat slightly, then add ethanol, and centrifuge to separate the solid. Then, the obtained product was washed with a mixed solvent of n-heptane/absolute ethanol (volume ratio: 2/1), and a precipitate was obtained after centrifugation. Washing was repeated 3-5 times to obtain a light yellow-green solid product, and finally the washed product was vacuum-dried at 60°C for 4 h.

The dried product was collected, and its composition and phase were tested by X-Ray powder diffractometer (XRD). The results showed that the obtained product was Er ₂ OS ₂ with a pure monoclinic crystal phase structure (Fig. 6a). Observation of its morphology and structure with a transmission electron microscope (TEM) (Fig. 6b), the results show that the morphology of the obtained Er ₂ OS ₂ is a one-dimensional linear structure with a length of several hundred nm and a diameter of about 2-3 nm. The diameter ratio is about 50-500, and they are arranged in parallel to form a 2D sheet structure.

Example 6

In a clean and dry reaction kettle with polytetrafluoroethylene lining (volume 50 mL), add 0.20~6.0 g Yb(NO ₃ ) ₃ 6 H ₂ O solid, 0.10~4.50 g thiourea solid , 2-10 mL oleic acid, 2-10 mL dodecylamine and 5-20 mL octadecene, seal the reaction kettle and transfer it to an oven, and raise it from room temperature to 195 °C at a rate of 6 °C/min, After 24 h of reaction, the temperature was naturally cooled to room temperature. A light brown gum was obtained. Add n-heptane, heat slightly, then add ethanol, and centrifuge to separate the solid. Then, the obtained primary product was washed with a mixed solvent of n-heptane/absolute ethanol (volume ratio: 2/1), and a precipitate was obtained after centrifugation. Washing was repeated 3-5 times to obtain a light yellow-green solid product, and finally the washed product was vacuum-dried at 60 °C for 4 h.

The dried product was collected, and its composition and phase were tested by X-Ray powder diffractometer (XRD). The results showed that the obtained product was pure monoclinic Yb ₂ OS ₂ (Fig. 7a). Its morphology and structure were observed with a transmission electron microscope (TEM) (Fig. 7b). The results showed that the obtained Yb ₂ OS ₂ had a one-dimensional linear structure with a length of several hundred nm and a diameter of about 2-3 nm. The diameter ratio is about 50-500, and they are arranged in parallel to form a 2D sheet structure.

Example 7-12

According to the same method as in Example 1, the nitrates of La, Ce, Pr, Nd, Sm, and Eu were used to replace the solid Y(NO ₃ ) ₃ 6 H ₂ O, and other conditions were the same as in Example 1 to prepare single Rare-earth isosulfur ultrafine nanowires and nanowire-based superstructures with oblique crystal phase structure.

Example 13 is the same as Example 1, except that the fatty acid used is octanoic acid, and the fatty amine is hexadecylamine.

Embodiment 14, with embodiment 2, difference is that the fatty acid that adopts is palmitic acid, and fatty amine is tetradecylamine.

Example 15 is the same as Example 3, except that the fatty acid used is lauric acid, and the fatty amine is decaamine.

Embodiment 16 is the same as embodiment 4, except that the fatty amine used is octylamine.

Claims (7)

1. A synthetic method of monoclinic phase rare earth isosulfur ultrafine nanowires and nanowire-based superstructures, characterized in that: in a mixed solvent composed of fatty acid, fatty amine and octadecene, the rare earth metal nitric acid The salt solid and thiourea solid are heated to 180-200°C for solid-liquid phase reaction, and the reaction product is separated to obtain the target product; Described method comprises the following steps: (1) Weigh 0.2-6.0 grams of rare earth metal nitrate solids and 0.1-4.50 grams of thiourea solids, and add them to a clean and dry reaction kettle lined with polytetrafluoroethylene; (2) Add 2-10 mL fatty acid, 2-10 mL fatty amine and 5-20 mL octadecene, seal the reactor, heat directly or place the reactor in an oven at a rate of 3°C-8°C per minute Raise the temperature to 180-200°C, keep it at this temperature for 10-60 hours, and then cool down to room temperature naturally; (3) The product obtained in step 2) is precipitated, centrifuged, washed, and vacuum-dried at room temperature to prepare monoclinic phase rare earth oxysulfur ultrafine nanowires and nanowire-based superstructures; The chemical formula of the rare earth isosulfur is Ln ₂ OS ₂ , wherein Ln=Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er or Yb. 2. The method for synthesizing rare earth isosulfur ultrafine nanowires and nanowire-based superstructures according to claim 1, wherein the molecular formula of the rare earth metal nitrate is Ln(NO ₃ ) ₃ xH ₂ O , wherein the rare earth metal element Ln is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er or Yb, and x is an integer from 0 to 6. 3. The method for synthesizing ultrafine nanowires and nanowire-based superstructures according to claim 1, characterized in that: the fatty acid is a C6-C22 straight-chain fatty acid, and the fatty amine is a C6-C22 straight-chain Aliphatic primary amines. 4. the synthetic method of ultrafine nanowire and nanowire-based superstructure according to claim 3, is characterized in that: described fatty acid is C8～C18 straight chain fatty acid, and described fatty amine is C8～C16 straight chain Aliphatic primary amines. 5. The method for synthesizing rare earth isosulfur ultrafine nanowires and nanowire-based superstructures according to claim 1, characterized in that: in the step (3), step 2) is first obtained by using n-heptane The product is dispersed, then added with absolute ethanol to make it settle, and finally centrifuged, washed with n-heptane/absolute ethanol mixed solvent for 3-5 times, and the finally obtained product is vacuum-dried at 60°C. 6. The method for synthesizing rare earth isosulfur ultrafine nanowires and nanowire-based superstructures according to claim 1, characterized in that the rare earth isosulfur is a linear structure, or the nanowires are parallel in two-dimensional space Arranged into a sheet-like structure, or the sheet-like structure self-organizes to form a layered structure or a tubular structure in three-dimensional space. 7. The method for synthesizing rare earth isosulfur ultrafine nanowires and nanowire-based superstructures according to claim 6, characterized in that: the diameter of the nanowires is 2 to 3 nm, and the aspect ratio is 50-500 .

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