阅读说明：本技术 一种组分可控的Bi-Te-Se三元纳米线及其制备方法 (Bi-Te-Se ternary nanowire with controllable components and preparation method thereof ) 是由 刘帅 刘迎港 陈国祥 于 2021-07-29 设计创作，主要内容包括：本发明提出一种组分可控的Bi-Te-Se三元纳米线及其制备方法。该方法首先制备出含有Te单质纳米线的溶液,然后在此基础上制备出Te-Se纳米线的溶液,最后再Te-Se纳米线上掺杂Bi元素,该方法通过低维化和多组元化增强缺陷对声子的散射作用,降低材料的晶格热导率,提高材料的热电性能。本发明制备过程简单,操作过程安全无污染,所得纳米线的元素分布均匀,结构稳定,在热电材料领域具有潜在的应用价值。(The invention provides a Bi-Te-Se ternary nanowire with controllable components and a preparation method thereof. According to the method, a solution containing Te single substance nano wires is prepared firstly, then a solution of Te-Se nano wires is prepared on the basis, and finally Bi elements are doped on the Te-Se nano wires. The preparation method has the advantages of simple preparation process, safe and pollution-free operation process, uniform element distribution of the obtained nanowire, stable structure and potential application value in the field of thermoelectric materials.)

1. The preparation method of the Bi-Te-Se ternary nanowire with controllable components is characterized by comprising the following steps:

step 1, dissolving tellurium oxide, polyvinylpyrrolidone and potassium hydroxide in ethylene glycol, heating, adding hydrazine hydrate, reacting to obtain a solution A containing Te simple substance nanowires, and cooling the solution A containing Te simple substance nanowires to 90 ℃ for later use;

step 2, dissolving selenious acid, concentrated hydrochloric acid and polyvinylpyrrolidone in ethylene glycol, uniformly mixing, adding a solution of Te elemental substance nanowires at 90 ℃, heating and reacting to generate a solution B containing Te-Se nanowires, and heating the solution B containing Te-Se nanowires to 120 ℃ for later use;

and 3, dissolving bismuth nitrate pentahydrate particles and a potassium hydroxide solution in ethylene glycol, stirring and heating to 80 ℃, naturally cooling the solution after the solution becomes colorless and transparent to obtain a solution C, mixing the solution B at 120 ℃ with the solution C, reacting, naturally cooling to obtain a solution D, centrifuging and washing the solution D, and drying to obtain black powder to obtain the Bi-Te-Se ternary nanowire.

2. The method for preparing a composition-controllable ternary nanowire of Bi-Te-Se as claimed in claim 1, wherein in step 1, the mixing ratio of tellurium oxide, polyvinylpyrrolidone and potassium hydroxide is 1.5 mmol: 0.75 g: 10 mmol.

3. The method for preparing the Bi-Te-Se ternary nanowire with controllable components as claimed in claim 1, wherein in the step 1, the addition amount of the hydrazine hydrate and the ratio of the tellurium oxide are 2 mL: 1.5 mmol.

4. The method for preparing a composition-controllable ternary nanowire of Bi-Te-Se as claimed in claim 1, wherein the temperature of the mixed solution of tellurium oxide, polyvinylpyrrolidone, potassium hydroxide and ethanol is 140 ℃ when adding hydrazine hydrate in step 1.

5. The method for preparing a Bi-Te-Se ternary nanowire with controllable composition as claimed in claim 1, wherein in step 2, the mixing ratio of selenious acid, concentrated hydrochloric acid and polyvinylpyrrolidone is (0.17-1.5) mmol: (2.5-5) mL: (0.5-1) g.

6. The method for preparing the composition-controllable ternary nanowire of Bi-Te-Se according to claim 1, wherein the heating temperature in step 2 is 110 ℃ and the reaction time is 1 h.

7. The method for preparing a composition-controllable ternary nanowire of Bi-Te-Se as claimed in claim 1, wherein in step 3, the mixing ratio of bismuth nitrate pentahydrate particles, potassium hydroxide and ethylene glycol is 2 mmol: 30 mmol: 10 mL.

8. The method for preparing the composition-controllable ternary nanowire of Bi-Te-Se according to claim 1, wherein in the step 3, the reaction temperature of the solution B and the solution C is 120 ℃ and the reaction time is 1 h.

9. The method for preparing the composition-controllable ternary nanowire of Bi-Te-Se as claimed in claim 1, wherein the drying temperature in step 3 is 50 ℃.

10. A Bi-Te-Se ternary nanowire of controllable composition prepared by the preparation method of any one of claims 1 to 9.

Technical Field

The invention belongs to the field of nano material preparation, and particularly relates to a Bi-Te-Se ternary nanowire with controllable components and a preparation method thereof.

Background

Thermoelectric conversion technology can utilize the intrinsic electric/heat transfer characteristics of materials to realize the interconversion between thermal energy and electric energy. The technology has the advantages of no pollution, no noise, long service life, high reliability and the like, is an ideal green and environment-friendly all-solid-state energy utilization mode, but the current thermoelectric technology still has the problem of low conversion efficiency.

The energy conversion rate of the thermoelectric material is mainly determined by a dimensionless thermoelectric figure of merit ZT of the material, and the expression is as follows: ZT ═ α (α)²σ/κ). T, where T is temperature, and σ, α, κ represent the electrical conductivity, Seebeck coefficient, and thermal conductivity, respectively, of the material. To increase the ZT value, the thermoelectric material must have both a higher electrical conductivity and a lower thermal conductivity. However, in general, the electrical conductivity and the thermal conductivity of a material have a strong positive correlation, i.e., increase and decrease, which is a great challenge for improving the thermoelectric figure of merit of the material. Bismuth telluride is a traditional thermoelectric material with best performance in the current medium-low temperature region, but the energy conversion efficiency of bismuth telluride cannot meet the requirement of commercial application.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a Bi-Te-Se ternary nanowire with controllable components and a preparation method thereof, so as to solve the technical problem that bismuth telluride in the prior art cannot meet the requirements of the existing commercial application.

In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:

a preparation method of a Bi-Te-Se ternary nanowire with controllable components comprises the following steps:

step 1, dissolving tellurium oxide, polyvinylpyrrolidone and potassium hydroxide in ethylene glycol, heating, adding hydrazine hydrate, reacting to obtain a solution A containing Te simple substance nanowires, and cooling the solution A containing Te simple substance nanowires to 90 ℃ for later use;

step 2, dissolving selenious acid, concentrated hydrochloric acid and polyvinylpyrrolidone in ethylene glycol, uniformly mixing, adding a solution of Te elemental substance nanowires at 90 ℃, heating and reacting to generate a solution B containing Te-Se nanowires, and heating the solution B containing Te-Se nanowires to 120 ℃ for later use;

and 3, dissolving bismuth nitrate pentahydrate particles and a potassium hydroxide solution in ethylene glycol, stirring and heating to 80 ℃, naturally cooling the solution after the solution becomes colorless and transparent to obtain a solution C, mixing the solution B at 120 ℃ with the solution C, reacting, naturally cooling to obtain a solution D, centrifuging and washing the solution D, and drying to obtain black powder to obtain the Bi-Te-Se ternary nanowire.

The invention is further improved in that:

preferably, in step 1, the mixing ratio of the tellurium oxide, the polyvinylpyrrolidone and the potassium hydroxide is 1.5 mmol: 0.75 g: 10 mmol.

Preferably, in step 1, the ratio of the added amount of hydrazine hydrate to tellurium oxide is 2 mL: 1.5 mmol.

Preferably, in step 1, the temperature of the mixed solution of tellurium oxide, polyvinylpyrrolidone, potassium hydroxide and ethanol is 140 ℃ when hydrazine hydrate is added.

Preferably, in the step 2, the mixing ratio of the selenious acid, the concentrated hydrochloric acid and the polyvinylpyrrolidone is (0.17-1.5) mmol: (2.5-5) mL: (0.5-1) g.

Preferably, in step 2, the heating temperature is 110 ℃ and the reaction time is 1 h.

Preferably, in step 3, the mixing ratio of the bismuth nitrate pentahydrate particles, the potassium hydroxide and the ethylene glycol is 2 mmol: 30 mmol: 10 mL.

Preferably, in step 3, the reaction temperature of the solution B and the solution C is 120 ℃, and the reaction time is 1 h.

Preferably, in step 3, the drying temperature is 50 ℃.

A component-controllable Bi-Te-Se ternary nanowire prepared by any one of the preparation methods.

Compared with the prior art, the invention has the following beneficial effects:

the invention provides a preparation method of a Bi-Te-Se ternary nanowire with adjustable components. According to the method, a solution containing Te single substance nano wires is prepared firstly, then a solution of Te-Se nano wires is prepared on the basis, and finally Bi elements are doped on the Te-Se nano wires. The preparation method has the advantages of simple preparation process, safe and pollution-free operation process, uniform element distribution of the obtained nanowire, stable structure and potential application value in the field of thermoelectric materials.

Low dimensional and multi-dimensional are two important ways to improve the thermoelectric figure of merit of materials. The energy distribution of the current carrier is changed from a continuous state along with the reduction of the material dimensionThe material is converted into a discrete state, the density of the state near the Fermi surface is greatly increased, the electric transport performance of the material can be improved, and the lattice thermal conductivity of the material is far lower than that of a bulk material due to the low-dimensional structural characteristics of the material. However, there is a physical limit to the thermal conductivity of any material, and further reduction in thermal conductivity cannot be achieved by only low dimensionality. Since Bi₂Te₃The corresponding alloying or doping process is easier due to the special layered structure and weaker interlayer interaction. The introduction of the doping elements can effectively regulate and control the energy band structure, optimize the carrier concentration of a system and further optimize the power factor of the material, and the introduction of the doping elements can improve the density of point defects to cause lattice strain, so that the lattice thermal conductivity is greatly reduced. For Bi₂Te₃In the system, the band structure is regulated and controlled by doping Se element, and Se replaces Te to be expressed as an n-type semiconductor. Although two elements of Se and Te are in the same main group, the arrangement rules of electrons outside the core are different, and the doping of Se can optimize Bi₂Te₃The carrier concentration in the system is increased, and the point defect density is increased, so that Bi can be increased₂Te₃The thermoelectric properties of (1).

Drawings

Fig. 1 is a schematic TEM and XRD characterization of Te nanowires obtained in step 1 of examples 1, 2, 3, 4; (Te nanowire made for the four examples)

Wherein (a) the figure is a TEM figure, and (b) the figure is an XRD characterization schematic diagram;

FIG. 2 is a schematic representation of SEM, EDS, TEM and XRD characterization of Te-Se nanowires obtained in step 2 of example 1;

wherein, the picture (a) is an SEM picture; (b) the image is a TEM image; (c) the figure is an XRD figure;

FIG. 3 is a schematic diagram showing SEM morphology, EDS and proportion characterization of three elements of the Bi-Te-Se ternary nanowire obtained in examples 1, 2 and 3;

wherein (a) and (b) are the characterization graphs of example 1; (c) and (d) is a characterization chart of example 2;

(e) and (f) is a characterization chart of example 3.

FIG. 4 is a schematic representation of SEM morphology, EDS mapping and three element ratio of the Bi-Te-Se ternary nanowire obtained in example 4;

wherein, the figure (a) is an SEM topography; (b) the figure is an EDS diagram; (c) the figure is an element proportion figure;

FIG. 5 is a schematic diagram of XRD characterization of the Bi-Te-Se ternary nanowires obtained in examples 1, 2, 3 and 4;

FIG. 6 is a schematic diagram of thermal conductivity test at 300K after the Bi-Te-Se ternary nanowire obtained in example 1, 2, 3, 4 is sintered into a block by hot pressing;

FIG. 7 is a flow chart of the preparation of the present invention;

Detailed Description

The invention is described in further detail below with reference to the accompanying drawings:

step 1. preparation of Te nano-wire: firstly, 1.5mmol of tellurium oxide, 0.75g of polyvinylpyrrolidone and 10mmol of potassium hydroxide are mixed and dissolved in 30mL of ethylene glycol, magnetic stirring is adopted to uniformly mix the tellurium oxide, 0.75g of polyvinylpyrrolidone and the potassium hydroxide, then the mixed solution is poured into a three-necked bottle, under the conditions of nitrogen protection, circulating water cooling and magnetic stirring, the mixed solution is heated to 140 ℃, 4mL of hydrazine hydrate with the concentration of 85% is rapidly injected, after heat preservation reaction is carried out for 1 hour, a solution A containing Te elementary substance nanowires is obtained, and the temperature of the solution is reduced to 90 ℃ for use;

step 2, preparing Te-Se nanowire: dissolving (0.17-1.5) mmol selenious acid, 18mol/L (2.5-5) mL concentrated hydrochloric acid and (0.5-1) g polyvinylpyrrolidone in 10mL ethylene glycol, and mixing by magnetic stirring for 3-5 min. Then injecting the solution into the Te nanowire solution with the temperature of 90 ℃ in the step 1 by a syringe (so as to ensure that selenious acid can be fully dissolved in the Te solution), heating the solution to 110 ℃, preserving heat and reacting for 1 hour to generate a solution B containing Te-Se nanowires, and heating the solution B to 120 ℃ for later use;

step 3, preparing the Bi-Te-Se nanowire: mixing and dissolving 2mmol of bismuth nitrate pentahydrate particles and 30mmol of potassium hydroxide in 10mL of ethylene glycol, heating to 80 ℃ under the condition of magnetic stirring, naturally cooling to 25 ℃ after the solution is changed from milky white suspension into colorless and transparent solution, and injecting the solution into the solution B of the Te-Se nanowire with the temperature of 120 ℃ in the step 2 for reaction, wherein the bismuth nitrate is completely dissolved after the solution is changed into colorless and transparent solution, and the precursor solution C is used as a precursor solution C of bismuth. After the reaction was carried out at 120 ℃ for 1 hour, it was naturally cooled to room temperature to obtain solution D. And taking out the solution, carrying out high-speed centrifugal washing, washing for 3 times by using deionized water and absolute ethyl alcohol respectively, and then placing the solution in a vacuum oven to be dried at 50 ℃ to obtain black powder, namely the Bi-Te-Se ternary nanowire. As can be seen from the combination of FIG. 7, Bi atoms chemically react with the entire Te-Se nanowire to form a BiTeSe nanowire, and the reaction only occurs on the surface of the nanowire, but the surface of the nanowire becomes rough after the chemical reaction.

The specific implementation mode is as follows:

example 1

First, 0.2394g (1.5mmol) of TeO were mixed₂0.75g of PVP and 5.6g (10mmol) of KOH were mixed at room temperature and dissolved in 30ml of EG, and the mixture was sufficiently dissolved by magnetic stirring to obtain a transparent liquid. And then pouring the solution into a 100ml three-necked bottle, heating the mixed solution to 140 ℃ under the conditions of nitrogen protection, circulating water cooling and magnetic stirring, quickly injecting 4ml of hydrazine hydrate through an injector, and carrying out heat preservation reaction for 1 hour to obtain the solution containing the Te nanowires. Cooling the solution to 90 ℃ for later use;

adding 0.0215g (0.17mmol) of selenious acid (H)₂SeO₃99.99 percent), 2.5mL of concentrated hydrochloric acid (HCl, 18mol/L) and 0.5g of PVP are dissolved in 10mL of ethylene glycol, the solution is magnetically stirred at room temperature for 3-5min, when the solute is completely dissolved and the solution is colorless and transparent, the solution is injected into a tellurium nanotube solution with the temperature of 90 ℃, the temperature is raised to 110 ℃, and the solution is subjected to heat preservation reaction for 1 hour, so that the solution containing the Te-Se binary nanowire is obtained. Adjusting the temperature of the solution to 120 ℃ for standby;

finally, 0.97g (2mmol) of Bi (NO)₃)₃·5H₂Mixing O with 1.68g (30mmol) KOH and dissolving in 10mL ethylene glycol, heating to 80 ℃ under the condition of magnetic stirring, and stopping heating after the solution is changed into colorless transparent liquid from milky suspension; and (3) hot-injecting the Bi precursor solution into a Te-Se nanowire solution at the temperature of 120 ℃. The reaction was completed after 1h of incubation at 120 ℃. The reaction solution was naturally cooled to room temperature, and then the solution was taken out and washed by centrifugation in a high-speed centrifugeWashing, washing by using deionized water and absolute ethyl alcohol for 3 times respectively, then placing in a vacuum oven, and drying at 50 ℃ to obtain black powder, namely the Bi-Te-Se ternary nanowire.

Plasma activated sintering was performed in an Ar atmosphere using a graphite mold. The sintering temperature is 350 ℃, the sintering pressure is 80MPa, and the heat preservation time is 5 min. The thermal conductivity of the sintered body measured at 300K by laser thermal conductivity method was 0.97 W.m-1. K-1.

As can be seen from FIG. 1, the obtained product has regular morphology, smooth surface, good dispersibility and nano-linear structure, the length is about 2-3 μm, and the linear diameter is about 20 nm. XRD phase characterization shows that the product is an elemental Te nanowire with good crystallinity.

As can be seen from fig. 2, the product obtained after the Se and Te nanowire reaction is still in the nanowire structure, which indicates that the morphology of the Te nanowire template is not damaged during the reaction process. The nanowire length is about 2 μm (fig. 2 (a)). The existence of a large number of uniformly structured nanowire structures proves the feasibility of large-scale preparation. Transmission electron microscopy analysis showed that the nanowires had uniform composition, good dispersibility, and a wire diameter of about 20nm (FIG. 2 (b)). The XRD phase was characterized as Te — Se binary nanowires with good crystallinity (fig. 2 (c)).

As can be seen from (a) and (b) in fig. 3, after the Te — Se nanowire reacts with Bi, the shape of the nanowire is still maintained, the size is not greatly changed, but the surface of the nanowire becomes rough. EDS energy spectrum analysis shows that the element ratio of the obtained Bi-Te-Se ternary nanowire is 41.25:53.09: 5.66.

Example 2

First, 0.2394g (1.5mmol) of TeO were mixed₂0.75g of PVP and 5.6g (10mmol) of KOH were mixed at room temperature and dissolved in 30mL of EG, and the mixture was sufficiently dissolved by magnetic stirring to obtain a transparent liquid. Then pouring the solution into a 100mL three-necked bottle, heating the mixed solution to 140 ℃ under the conditions of nitrogen protection, circulating water cooling and magnetic stirring, quickly injecting 4mL of hydrazine hydrate through an injector, carrying out heat preservation reaction for 1 hour to obtain a solution A containing Te nanowires, and cooling the solution to 90 ℃ for later use;

0.0323g (0.25mmol) selenious acid (H)₂SeO₃，99.99 percent), 3ml of concentrated hydrochloric acid (HCl, 18mol/L) and 0.6g of PVP are dissolved in 10ml of ethylene glycol, the solution is magnetically stirred for 3-5min at room temperature, when the solute is completely dissolved and the solution is colorless and transparent, the solution is injected into a tellurium nanotube solution with the temperature of 90 ℃, the temperature is raised to 110 ℃, and the temperature is kept for reaction for 1 hour, thus obtaining the solution containing the Te-Se binary nanowire. Adjusting the temperature of the solution to 120 ℃ for standby;

finally, 0.97g (2mmol) of Bi (NO)₃)₃·5H₂Mixing O with 1.68g (30mmol) KOH, dissolving in 10ml ethylene glycol, heating to 80 ℃ under magnetic stirring, and stopping heating when the solution is changed from milky suspension into colorless transparent liquid; and (3) hot-injecting the Bi precursor solution into a Te-Se nanowire solution at the temperature of 120 ℃. The reaction was completed after 1h of incubation at 120 ℃. And naturally cooling the reaction solution to room temperature, then taking out the solution, centrifugally washing the solution by using a high-speed centrifuge, washing the solution for 3 times by using deionized water and absolute ethyl alcohol respectively, then placing the solution in a vacuum oven, and drying the solution at 50 ℃ to obtain black powder, namely the Bi-Te-Se ternary nanowire.

Plasma activated sintering was performed in an Ar atmosphere using a graphite mold. The sintering temperature is 350 ℃, the sintering pressure is 80MPa, and the heat preservation time is 5 min. The thermal conductivity of the sintered body measured at 300K by laser thermal conductivity method was 0.91 W.m-1. K-1.

As can be seen from (c) and (d) in fig. 3, after the Te — Se nanowire reacts with Bi, the shape of the nanowire is still maintained, the size is not greatly changed, but the surface of the nanowire becomes rough. EDS energy spectrum analysis shows that the element proportion of the obtained Bi-Te-Se ternary nanowire is 38.54:53.07: 8.39.

Example 3

First, 0.2394g (1.5mmol) of TeO were mixed₂0.75g of PVP and 5.6g (10mmol) of KOH were mixed at room temperature and dissolved in 30ml of EG, and the mixture was sufficiently dissolved by magnetic stirring to obtain a transparent liquid. And then pouring the solution into a 100mL three-necked bottle, heating the mixed solution to 140 ℃ under the conditions of nitrogen protection, circulating water cooling and magnetic stirring, quickly injecting 4mL of hydrazine hydrate through an injector, and carrying out heat preservation reaction for 1 hour to obtain the solution containing the Te nanowires. Cooling the solution to 90 deg.C for use；

Adding 0.0645g (0.5mmol) of selenious acid (H)₂SeO₃99.99 percent), 3.5mL of concentrated hydrochloric acid (HCl, 18mol/L) and 0.8g of PVP are dissolved in 10mL of ethylene glycol, the solution is magnetically stirred for 3min at room temperature, when the solute is completely dissolved and the solution is colorless and transparent, the solution is injected into a tellurium nanotube solution with the temperature of 90 ℃, the temperature is raised to 110 ℃, and the heat preservation reaction is carried out for 1 hour, thus obtaining the solution containing the Te-Se binary nanowire. Adjusting the temperature of the solution to 120 ℃ for standby;

finally, 0.97g (2mmol) of Bi (NO)₃)₃·5H₂Mixing O with 1.68g (30mmol) KOH, dissolving in 10ml ethylene glycol, heating to 80 ℃ under magnetic stirring, and stopping heating when the solution is changed from milky suspension into colorless transparent liquid; and (3) hot-injecting the Bi precursor solution into a Te-Se nanowire solution at the temperature of 120 ℃. The reaction was completed after 1h of incubation at 120 ℃. And naturally cooling the reaction solution to room temperature, then taking out the solution, centrifugally washing the solution by using a high-speed centrifuge, washing the solution for 3 times by using deionized water and absolute ethyl alcohol respectively, then placing the solution in a vacuum oven, and drying the solution at 50 ℃ to obtain black powder, namely the Bi-Te-Se ternary nanowire.

Plasma activated sintering was performed in an Ar atmosphere using a graphite mold. The sintering temperature is 350 ℃, the sintering pressure is 80MPa, and the heat preservation time is 5 min. The thermal conductivity of the sintered body measured at 300K by laser photothermal method was 0.72 W.m-1. K-1.

As can be seen from (e) and (f) of fig. 3, after the Te — Se nanowire reacts with Bi, the shape of the nanowire is still maintained, the size is not greatly changed, but the surface of the nanowire becomes rough. EDS energy spectrum analysis shows that the element ratio of the Bi-Te-Se ternary nanowire is 40.76:44.60: 14.64.

Example 4

First, 0.2394g (1.5mmol) of TeO were mixed₂0.75g of PVP and 5.6g (10mmol) of KOH were mixed at room temperature and dissolved in 30ml of EG, and the mixture was sufficiently dissolved by magnetic stirring to obtain a transparent liquid. Then pouring into a 100ml three-neck bottle, heating the mixed solution to 140 ℃ under the conditions of nitrogen protection, circulating water cooling and magnetic stirring, and then quickly injecting 4ml hydrazine hydrate through a syringeAnd keeping the temperature for reaction for 1 hour to obtain a solution containing the Te nano-wire. Cooling the solution to 90 ℃ for later use;

0.1935g (1.5mmol) selenious acid (H)₂SeO₃99.99 percent of the total amount of the Te-Se binary nanowire solution, 5ml of concentrated hydrochloric acid (HCl, 18mol/L) and 1g of PVP are dissolved in 10ml of ethylene glycol, the solution is magnetically stirred for-5 min at room temperature, when the solute is completely dissolved and the solution is colorless and transparent, the solution is injected into a tellurium nanotube solution with the temperature of 90 ℃, the temperature is raised to 110 ℃, and the temperature is kept for reaction for 1 hour, so that the solution containing the Te-Se binary nanowire is obtained. Adjusting the temperature of the solution to 120 ℃ for standby;

finally, 0.97g (2mmol) of Bi (NO)₃)₃·5H₂Mixing O with 1.68g (30mmol) KOH, dissolving in 10ml ethylene glycol, heating to 80 ℃ under magnetic stirring, and stopping heating when the solution is changed from milky suspension into colorless transparent liquid; and (3) hot-injecting the Bi precursor solution into a Te-Se nanowire solution at the temperature of 120 ℃. The reaction was completed after 1h of incubation at 120 ℃. And naturally cooling the reaction solution to room temperature, then taking out the solution, centrifugally washing the solution by using a high-speed centrifuge, washing the solution for 3 times by using deionized water and absolute ethyl alcohol respectively, then placing the solution in a vacuum oven, and drying the solution at 50 ℃ to obtain black powder, namely the Bi-Te-Se ternary nanowire.

Plasma activated sintering was performed in an Ar atmosphere using a graphite mold. The sintering temperature is 350 ℃, the sintering pressure is 80MPa, and the heat preservation time is 5 min. The thermal conductivity of the sintered body measured at 300K by laser thermal conductivity method was 0.55 W.m-1. K-1.

It can be seen from fig. 4 that the Te-Se nanowire has the nanowire morphology after reacting with Bi, the dimensional change is not large, but the nanowire surface becomes rough. The energy spectrum surface scanning analysis shows that the Bi, Te and Se are uniformly distributed on the nano-wire. EDS energy spectrum analysis shows that the element ratio of the obtained Bi-Te-Se ternary nanowire is 36.62:32.50: 30.88.

As can be seen from FIG. 5, the XRD patterns of the Bi-Te-Se ternary nanowires in examples 1-4 at different contents of components were consistent with those of rhombohedral Bi₂Te₃The diffraction peak positions of the crystals are consistent, and no impurity peak exists. Description of SAnd e, replacing the crystal lattice position of Te to form the Bi-Te-Se ternary nanowire.

As can be seen from FIG. 6, the thermal conductivities of the sintered bulk of Bi-Te-Se nanowires at various contents of the components in examples 1 to 4 were measured at 300K using a laser calorimetry method. It can be seen that the thermal conductivity of all ternary nanowires is much lower than that of the Bi2Te3 crystal (about 1.5W · m-1 · K-1 according to the literature). In addition, with the gradual increase of the Se content, the point defect density of the nanowire is increased, the scattering effect of the defect on phonons is stronger, and therefore the thermal conductivity is obviously reduced.

Example 5

First, 0.2394g (1.5mmol) of TeO were mixed₂0.75g of PVP and 5.6g (10mmol) of KOH were mixed at room temperature and dissolved in 30ml of EG, and the mixture was sufficiently dissolved by magnetic stirring to obtain a transparent liquid. And then pouring the solution into a 100ml three-necked bottle, heating the mixed solution to 140 ℃ under the conditions of nitrogen protection, circulating water cooling and magnetic stirring, quickly injecting 4ml of hydrazine hydrate through an injector, and carrying out heat preservation reaction for 1 hour to obtain the solution containing the Te nanowires. Cooling the solution to 90 ℃ for later use;

adding 0.2mmol selenious acid (H)₂SeO₃99.99 percent), 2.8mL of concentrated hydrochloric acid (HCl, 18mol/L) and 0.55g of PVP are dissolved in 10mL of ethylene glycol, the solution is magnetically stirred at room temperature for 3-5min, when the solute is completely dissolved and the solution is colorless and transparent, the solution is injected into a tellurium nanotube solution with the temperature of 90 ℃, the temperature is raised to 110 ℃, and the solution is subjected to heat preservation reaction for 1 hour, so that the solution containing the Te-Se binary nanowire is obtained. Adjusting the temperature of the solution to 120 ℃ for standby;

finally, 0.97g (2mmol) of Bi (NO)₃)₃·5H₂Mixing O with 1.68g (30mmol) KOH and dissolving in 10mL ethylene glycol, heating to 80 ℃ under the condition of magnetic stirring, and stopping heating after the solution is changed into colorless transparent liquid from milky suspension; and (3) hot-injecting the Bi precursor solution into a Te-Se nanowire solution at the temperature of 120 ℃. The reaction was completed after 1h of incubation at 120 ℃. Naturally cooling the reaction solution to room temperature, taking out the solution, centrifugally washing the solution by using a high-speed centrifuge, washing the solution for 3 times by using deionized water and absolute ethyl alcohol respectively, and then placing the solutionDrying the mixture in a vacuum oven at 50 ℃ to obtain black powder, namely the Bi-Te-Se ternary nanowire.

Example 6

First, 0.2394g (1.5mmol) of TeO were mixed₂0.75g of PVP and 5.6g (10mmol) of KOH were mixed at room temperature and dissolved in 30ml of EG, and the mixture was sufficiently dissolved by magnetic stirring to obtain a transparent liquid. And then pouring the solution into a 100ml three-necked bottle, heating the mixed solution to 140 ℃ under the conditions of nitrogen protection, circulating water cooling and magnetic stirring, quickly injecting 4ml of hydrazine hydrate through an injector, and carrying out heat preservation reaction for 1 hour to obtain the solution containing the Te nanowires. Cooling the solution to 90 ℃ for later use;

adding 0.3mmol selenious acid (H)₂SeO₃99.99 percent), 3.2mL of concentrated hydrochloric acid (HCl, 18mol/L) and 0.7g of PVP are dissolved in 10mL of ethylene glycol, the solution is magnetically stirred at room temperature for 3-5min, when the solute is completely dissolved and the solution is colorless and transparent, the solution is injected into a tellurium nanotube solution with the temperature of 90 ℃, the temperature is raised to 110 ℃, and the solution is subjected to heat preservation reaction for 1 hour, so that the solution containing the Te-Se binary nanowire is obtained. Adjusting the temperature of the solution to 120 ℃ for standby;

finally, 0.97g (2mmol) of Bi (NO)₃)₃·5H₂Mixing O with 1.68g (30mmol) KOH and dissolving in 10mL ethylene glycol, heating to 80 ℃ under the condition of magnetic stirring, and stopping heating after the solution is changed into colorless transparent liquid from milky suspension; and (3) hot-injecting the Bi precursor solution into a Te-Se nanowire solution at the temperature of 120 ℃. The reaction was completed after 1h of incubation at 120 ℃. And naturally cooling the reaction solution to room temperature, then taking out the solution, centrifugally washing the solution by using a high-speed centrifuge, washing the solution for 3 times by using deionized water and absolute ethyl alcohol respectively, then placing the solution in a vacuum oven, and drying the solution at 50 ℃ to obtain black powder, namely the Bi-Te-Se ternary nanowire.

Example 7

First, 0.2394g (1.5mmol) of TeO were mixed₂0.75g of PVP and 5.6g (10mmol) of KOH were mixed at room temperature and dissolved in 30ml of EG, and the mixture was sufficiently dissolved by magnetic stirring to obtain a transparent liquid. Then poured into a 100ml three-necked bottle and stirred under the conditions of nitrogen protection, circulating water cooling and magnetic stirringHeating the mixed solution to 140 ℃, quickly injecting 4ml of hydrazine hydrate through an injector, and carrying out heat preservation reaction for 1 hour to obtain a solution containing the Te nano-wires. Cooling the solution to 90 ℃ for later use;

adding 0.7mmol selenious acid (H)₂SeO₃99.99 percent), 3.8mL of concentrated hydrochloric acid (HCl, 18mol/L) and 0.85g of PVP are dissolved in 10mL of ethylene glycol, the solution is magnetically stirred at room temperature for 3-5min, when the solute is completely dissolved and the solution is colorless and transparent, the solution is injected into a tellurium nanotube solution with the temperature of 90 ℃, the temperature is raised to 110 ℃, and the solution is subjected to heat preservation reaction for 1 hour, so that the solution containing the Te-Se binary nanowire is obtained. Adjusting the temperature of the solution to 120 ℃ for standby;

finally, 0.97g (2mmol) of Bi (NO)₃)₃·5H₂Mixing O with 1.68g (30mmol) KOH and dissolving in 10mL ethylene glycol, heating to 80 ℃ under the condition of magnetic stirring, and stopping heating after the solution is changed into colorless transparent liquid from milky suspension; and (3) hot-injecting the Bi precursor solution into a Te-Se nanowire solution at the temperature of 120 ℃. The reaction was completed after 1h of incubation at 120 ℃. And naturally cooling the reaction solution to room temperature, then taking out the solution, centrifugally washing the solution by using a high-speed centrifuge, washing the solution for 3 times by using deionized water and absolute ethyl alcohol respectively, then placing the solution in a vacuum oven, and drying the solution at 50 ℃ to obtain black powder, namely the Bi-Te-Se ternary nanowire.

Example 8

First, 0.2394g (1.5mmol) of TeO were mixed₂0.75g of PVP and 5.6g (10mmol) of KOH were mixed at room temperature and dissolved in 30ml of EG, and the mixture was sufficiently dissolved by magnetic stirring to obtain a transparent liquid. And then pouring the solution into a 100ml three-necked bottle, heating the mixed solution to 140 ℃ under the conditions of nitrogen protection, circulating water cooling and magnetic stirring, quickly injecting 4ml of hydrazine hydrate through an injector, and carrying out heat preservation reaction for 1 hour to obtain the solution containing the Te nanowires. Cooling the solution to 90 ℃ for later use;

adding 0.9mmol selenious acid (H)₂SeO₃99.99 percent), 4mL of concentrated hydrochloric acid (HCl, 18mol/L) and 0.9g of PVP are dissolved in 10mL of ethylene glycol, the solution is stirred for 3-5min by magnetic force at room temperature, and when the solute is completely dissolved, the solution is free fromThe solution is transparent in color, and is injected into a tellurium nanotube solution with the temperature of 90 ℃, the temperature is raised to 110 ℃, and the solution is subjected to heat preservation reaction for 1 hour to obtain the solution containing the Te-Se binary nanowire. Adjusting the temperature of the solution to 120 ℃ for standby;

finally, 0.97g (2mmol) of Bi (NO)₃)₃·5H₂Mixing O with 1.68g (30mmol) KOH and dissolving in 10mL ethylene glycol, heating to 80 ℃ under the condition of magnetic stirring, and stopping heating after the solution is changed into colorless transparent liquid from milky suspension; and (3) hot-injecting the Bi precursor solution into a Te-Se nanowire solution at the temperature of 120 ℃. The reaction was completed after 1h of incubation at 120 ℃. And naturally cooling the reaction solution to room temperature, then taking out the solution, centrifugally washing the solution by using a high-speed centrifuge, washing the solution for 3 times by using deionized water and absolute ethyl alcohol respectively, then placing the solution in a vacuum oven, and drying the solution at 50 ℃ to obtain black powder, namely the Bi-Te-Se ternary nanowire.

Example 9

First, 0.2394g (1.5mmol) of TeO were mixed₂0.75g of PVP and 5.6g (10mmol) of KOH were mixed at room temperature and dissolved in 30ml of EG, and the mixture was sufficiently dissolved by magnetic stirring to obtain a transparent liquid. And then pouring the solution into a 100ml three-necked bottle, heating the mixed solution to 140 ℃ under the conditions of nitrogen protection, circulating water cooling and magnetic stirring, quickly injecting 4ml of hydrazine hydrate through an injector, and carrying out heat preservation reaction for 1 hour to obtain the solution containing the Te nanowires. Cooling the solution to 90 ℃ for later use;

1mmol of selenious acid (H)₂SeO₃99.99 percent), 4.5mL of concentrated hydrochloric acid (HCl, 18mol/L) and 0.92g of PVP are dissolved in 10mL of ethylene glycol, the solution is magnetically stirred at room temperature for 3-5min until the solute is completely dissolved and the solution is colorless and transparent, the solution is injected into a tellurium nanotube solution with the temperature of 90 ℃, the temperature is raised to 110 ℃, and the solution is subjected to heat preservation reaction for 1 hour, so that the solution containing the Te-Se binary nanowire is obtained. Adjusting the temperature of the solution to 120 ℃ for standby;

finally, 0.97g (2mmol) of Bi (NO)₃)₃·5H₂O is mixed with 1.68g (30mmol) KOH and dissolved in 10mL ethylene glycol and heated to 80 ℃ under magnetic stirring until the solution turns milky whiteStopping heating after the suspension is converted into colorless transparent liquid; and (3) hot-injecting the Bi precursor solution into a Te-Se nanowire solution at the temperature of 120 ℃. The reaction was completed after 1h of incubation at 120 ℃. And naturally cooling the reaction solution to room temperature, then taking out the solution, centrifugally washing the solution by using a high-speed centrifuge, washing the solution for 3 times by using deionized water and absolute ethyl alcohol respectively, then placing the solution in a vacuum oven, and drying the solution at 50 ℃ to obtain black powder, namely the Bi-Te-Se ternary nanowire.

Example 10

First, 0.2394g (1.5mmol) of TeO were mixed₂0.75g of PVP and 5.6g (10mmol) of KOH were mixed at room temperature and dissolved in 30ml of EG, and the mixture was sufficiently dissolved by magnetic stirring to obtain a transparent liquid. And then pouring the solution into a 100ml three-necked bottle, heating the mixed solution to 140 ℃ under the conditions of nitrogen protection, circulating water cooling and magnetic stirring, quickly injecting 4ml of hydrazine hydrate through an injector, and carrying out heat preservation reaction for 1 hour to obtain the solution containing the Te nanowires. Cooling the solution to 90 ℃ for later use;

1.2mmol of selenious acid (H)₂SeO₃99.99 percent), 4.8mL of concentrated hydrochloric acid (HCl, 18mol/L) and 0.98g of PVP are dissolved in 10mL of ethylene glycol, the solution is magnetically stirred at room temperature for 3-5min, when the solute is completely dissolved and the solution is colorless and transparent, the solution is injected into a tellurium nanotube solution with the temperature of 90 ℃, the temperature is raised to 110 ℃, and the solution is subjected to heat preservation reaction for 1 hour, so that the solution containing the Te-Se binary nanowire is obtained. Adjusting the temperature of the solution to 120 ℃ for standby;

finally, 0.97g (2mmol) of Bi (NO)₃)₃·5H₂Mixing O with 1.68g (30mmol) KOH and dissolving in 10mL ethylene glycol, heating to 80 ℃ under the condition of magnetic stirring, and stopping heating after the solution is changed into colorless transparent liquid from milky suspension; and (3) hot-injecting the Bi precursor solution into a Te-Se nanowire solution at the temperature of 120 ℃. The reaction was completed after 1h of incubation at 120 ℃. And naturally cooling the reaction solution to room temperature, then taking out the solution, centrifugally washing the solution by using a high-speed centrifuge, washing the solution for 3 times by using deionized water and absolute ethyl alcohol respectively, then placing the solution in a vacuum oven, and drying the solution at 50 ℃ to obtain black powder, namely the Bi-Te-Se ternary nanowire.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.