阅读说明：本技术 一种表面负载金颗粒的碲化铋纳米片及其制备方法 (Bismuth telluride nanosheet with gold particles loaded on surface and preparation method thereof ) 是由 刘帅 余历军 陈国祥 于 2021-09-09 设计创作，主要内容包括：本发明公开了一种表面负载金颗粒的碲化铋纳米片及其制备方法。该方法采用溶剂热合成法：首先,将五水硝酸铋、亚碲酸钠和氢氧化钠混合溶于乙二醇,在反应釜中加热进行溶剂热反应,生成碲化铋纳米片；其次,将四氯金酸溶于去离子水,通过水解反应得到金纳米颗粒,并与碲化铋纳米片溶液混合,通过纳米片表面的物理吸附作用,得到表面负载金纳米颗粒的碲化铋纳米片。(The invention discloses a bismuth telluride nanosheet with gold particles loaded on the surface and a preparation method thereof. The method adopts a solvent thermal synthesis method: firstly, mixing bismuth nitrate pentahydrate, sodium tellurite and sodium hydroxide, dissolving the mixture in ethylene glycol, heating the mixture in a reaction kettle to perform solvothermal reaction, and generating bismuth telluride nanosheets; and secondly, dissolving tetrachloroauric acid in deionized water, obtaining gold nanoparticles through hydrolysis reaction, mixing the gold nanoparticles with the bismuth telluride nanosheet solution, and obtaining the bismuth telluride nanosheet with the gold nanoparticles loaded on the surface through the physical adsorption effect of the nanosheet surface.)

1. A preparation method of a bismuth telluride nanosheet with gold particles loaded on the surface is characterized by comprising the following steps:

step 1, mixing bismuth nitrate pentahydrate, sodium tellurite and sodium hydroxide in ethylene glycol, and heating to obtain transparent liquid;

step 2, reacting the transparent liquid in a reaction kettle to obtain a solution containing bismuth telluride sheets, cleaning to obtain a reaction product, and dissolving the reaction product in water to obtain a bismuth telluride nanosheet solution;

and 3, mixing the bismuth telluride nanosheet solution and the tetrachloroauric acid solution, stirring to obtain a product solution, centrifugally washing and drying the product solution to obtain the bismuth telluride nanosheets with gold nanoparticles loaded on the surfaces.

2. The method for preparing the bismuth telluride nanosheet with the gold particles loaded on the surface, as recited in claim 1, wherein in step 1, the molar ratio of bismuth nitrate pentahydrate to sodium tellurite to sodium hydroxide is 2:3: 10.

3. The method for preparing bismuth telluride nanosheets having gold particles loaded on the surfaces thereof as recited in claim 1, wherein the heating temperature in step 1 is 80 ℃.

4. The method for preparing the bismuth telluride nanosheet with the gold particles loaded on the surface thereof as defined in claim 1, wherein the reaction temperature in step 2 is 240 ℃ and the reaction time is 36 h.

5. The method for preparing the bismuth telluride nanosheet with gold particles loaded on the surface, as recited in claim 1, wherein in step 3, the molar ratio of the tetrachloroauric acid solution to the bismuth nitrate pentahydrate is (0.4-1): 2.

6. the method for preparing the bismuth telluride nanosheet with the gold particles loaded on the surface, according to claim 1, wherein the tetrachloroauric acid solution is added to the bismuth telluride nanosheet solution in batches by a pipette gun.

7. The method for preparing the bismuth telluride nanosheet with the gold particles loaded on the surface thereof as defined in claim 1, wherein in the step 3, the stirring time is 0.5-1 h.

8. The method for preparing bismuth telluride nanosheets with gold particles loaded on the surfaces thereof as recited in claim 1, wherein in step 3, the drying temperature is 50 ℃.

9. The bismuth telluride nanosheet with gold particles loaded on the surface, which is obtained by the preparation method of any one of claims 1 to 8, is in a black powder form, the diameter range of the nanosheet is 260-320 nm, and the average thickness is 30 nm.

Technical Field

The invention belongs to the technical field of nano materials, and particularly relates to a bismuth telluride nanosheet with gold particles loaded on the surface and a preparation method thereof.

Background

The thermoelectric technology can realize the interconversion of heat energy and electric energy, and is an ideal green environment-friendly all-solid-state energy generation mode. The thermoelectric conversion technology mainly utilizes the intrinsic transmission characteristics of materials to realize energy conversion, and has the advantages of no pollution, no noise, long service life, high reliability and the like. However, the current thermoelectric materials still have the problem of low conversion efficiency.

The conversion efficiency of thermoelectric materials depends mainly on the dimensionless thermoelectric figure of merit of the material, ZT ═ alpha²σ/κ). T, where T represents temperature, and σ, α, κ represent the electrical conductivity, Seebeck coefficient and thermal conductivity, respectively, of the material.

According to the expression of thermoelectric figure of merit, a thermoelectric material with excellent performance should have both high electrical conductivity and low thermal conductivity. However, for most materials, the electrical conductivity and the thermal conductivity have a strong correlation, and both are usually increased and decreased, thereby bringing technical challenges to the improvement of the thermoelectric figure of merit of the material. Bi₂Te₃The thermoelectric material is the traditional thermoelectric material with the most excellent performance in the medium-low temperature region, but the energy conversion efficiency of the thermoelectric material cannot meet the requirement of commercial application.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a bismuth telluride nanosheet with gold particles loaded on the surface and a preparation method thereof, so as to solve the problem of Bi in the prior art₂Te₃The problem of energy conversion efficiency in the prior art is difficult to satisfy.

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

a preparation method of a bismuth telluride nanosheet with gold particles loaded on the surface comprises the following steps:

step 1, mixing bismuth nitrate pentahydrate, sodium tellurite and sodium hydroxide in ethylene glycol, and heating to obtain transparent liquid;

step 2, reacting the transparent liquid in a reaction kettle to obtain a solution containing bismuth telluride sheets, cleaning to obtain a reaction product, and dissolving the reaction product in water to obtain a bismuth telluride nanosheet solution;

and 3, mixing the bismuth telluride nanosheet solution and the tetrachloroauric acid solution, stirring to obtain a product solution, centrifugally washing and drying the product solution to obtain the bismuth telluride nanosheets with gold nanoparticles loaded on the surfaces.

The invention is further improved in that:

preferably, in the step 1, the molar ratio of the bismuth nitrate pentahydrate to the sodium tellurite to the sodium hydroxide is 2:3: 10.

Preferably, the heating temperature in step 1 is 80 ℃.

Preferably, the reaction temperature in the step 2 is 240 ℃ and the reaction time is 36 h.

Preferably, in step 3, the molar ratio of the tetrachloroauric acid solution to the bismuth nitrate pentahydrate is (0.4-1): 2.

preferably, the tetrachloroauric acid solution is added in batches through a liquid transfer gun when being added into the bismuth telluride nanosheet solution.

Preferably, in step 3, the stirring time is 0.5-1 h.

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

The bismuth telluride nanosheet with gold particles loaded on the surface is obtained by any one of the preparation methods, is in a black powder form, and has the diameter range of 260-320 nm and the average thickness of 30 nm.

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

the invention discloses a preparation method of a bismuth telluride nanosheet with gold nanoparticles loaded on the surface. The method adopts a solvent thermal synthesis method: firstly, mixing bismuth nitrate pentahydrate, sodium tellurite and sodium hydroxide, dissolving the mixture in ethylene glycol, heating the mixture in a reaction kettle to perform solvothermal reaction, and generating bismuth telluride nanosheets; and secondly, dissolving tetrachloroauric acid in deionized water, obtaining gold nanoparticles through hydrolysis reaction, mixing the gold nanoparticles with the bismuth telluride nanosheet solution, and obtaining the bismuth telluride nanosheet with the gold nanoparticles loaded on the surface through the physical adsorption effect of the nanosheet surface. On one hand, the high-conductivity gold nanoparticles are added, so that the conductivity of the bismuth telluride nanosheet is improved; on the other hand, the gold nanoparticles can generate scattering effect on phonons, the heat conductivity of the nanosheets is reduced, and the thermoelectric property of the material is further improved. The invention has simple preparation process, safe operation process and no pollution. The obtained bismuth telluride nanosheet with gold nanoparticles loaded on the surface has uniform phase and low thermal conductivity. Low dimensional and defect introduction are important ways to improve the thermoelectric figure of merit of materials. On the one hand, low dimensional materials generally have superior electrical transport properties than their bulk structure; on the other hand, the surface of the low-dimensional material and the introduced defects can generate strong scattering effect on phonons, reduce the thermal conductivity of the material and improve the thermoelectric performance of the material.

The invention can obviously reduce the lattice thermal conductivity of the material and improve the thermoelectric property of the material. The invention has simple synthesis process and good operation repeatability, and has higher research and utilization value in the field of thermoelectric materials.

Drawings

Fig. 1 is a schematic diagram of SEM morphology and XRD characterization of the bismuth telluride nanosheet obtained in step 1 of example 1; wherein (a) is an SEM representation of pure Bi2Te3 nanosheets; (b) the figure is the XRD pattern of Bi2Te3 nano-sheets prepared in example 1.

FIG. 2 is a schematic view of SEM morphology and EDS component characterization of the bismuth telluride nanosheets loaded with gold nanoparticles on the surface, obtained in example 1;

wherein, the figure (a) is an SEM topography figure with the magnification of 1 mu m; (b) the figure is an SEM image at 200nm magnification; (c) the figure is an EDS component characterization attempt;

FIG. 3 is a schematic view of SEM morphology and EDS component characterization of the bismuth telluride nanosheets loaded with gold nanoparticles on the surface, obtained in example 2;

wherein, the figure (a) is an SEM topography figure with the magnification of 1 mu m; (b) the figure is an SEM image at 200nm magnification; (c) the figure is an EDS component characterization attempt;

FIG. 4 is a schematic diagram of the HRTEM microstructure, EDS mapping and components of the bismuth telluride nanosheet with gold nanoparticles loaded on the surface, obtained in example 2;

wherein, the (a) diagram, (b) diagram and (c) diagram are microstructural diagrams; (d) panels (e) and (f) are EDS spectra of the three elements, respectively; (g) the figure is a component schematic diagram.

FIG. 5 is an XRD representation of the gold nanoparticle-loaded bismuth telluride nanoplates obtained in examples 1 and 2;

FIG. 6 is a comparison graph of the thermal conductivity of the product obtained in examples 1 and 2 and a bismuth telluride nanosheet with temperature variation;

FIG. 7 is a graph of the topographical variations of the inventive fabrication process.

Detailed Description

The invention is described in further detail below with reference to the following figures and specific examples:

referring to fig. 7, the invention discloses a bismuth telluride nanosheet with gold particles loaded on the surface and a preparation method thereof, and the specific steps are as follows:

step 1, mixing bismuth nitrate pentahydrate, sodium tellurite and sodium hydroxide according to a molar ratio of 2:3:10, mixing and dissolving 80mL of ethylene glycol, heating to 80 ℃ under the action of magnetic stirring, transferring the solution into a reaction kettle after the solution is converted from milky turbid liquid into colorless transparent liquid, reacting in an oven at the temperature of 240 ℃ for 36 hours, and naturally cooling to room temperature to obtain the solution containing the bismuth telluride nanosheets. After the solution is centrifugally washed for 3 times by deionized water and absolute ethyl alcohol, dissolving the product in the deionized water and carrying out uninterrupted magnetic stirring to obtain a bismuth telluride nanosheet solution, so that nanosheets can be uniformly dissolved in the deionized water, and uniform loading can be conveniently realized when Au particles are loaded in the next step;

and 2, dissolving tetrachloroauric acid in a certain amount of deionized water, gently shaking until the tetrachloroauric acid is completely dissolved, and slowly adding the tetrachloroauric acid and the pentahydrate bismuth nitrate into the bismuth telluride nanosheet solution obtained in the step 1 in batches by using a liquid transfer gun, wherein the molar ratio of the tetrachloroauric acid to the pentahydrate bismuth nitrate is (0.4-1): adding tetrachloroauric acid in batches to avoid generated nano Au particle agglomeration, adding 1-2 mL of tetrachloroauric acid in 3-5 times, and then magnetically stirring the mixed solution at room temperature for 0.5-1 hour. 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 centrifugal product in a vacuum oven for drying at 50 ℃ to obtain black powder, namely the bismuth telluride nanosheet with gold nanoparticles loaded on the surface. The diameter of the nano-sheet is 260-320 nm, and the average thickness is 30 nm.

Example 1

0.97g (2mmol) of Bi (NO)₃)₃·5H₂O，0.664g(3mmol)Na₂TeO₃With 4g (10mmol) of NaOHHeating 80ml of ethylene glycol to 80 ℃ under the action of magnetic stirring, transferring the solution into a 100ml reaction kettle after the solution is changed into colorless transparent liquid from milky turbid liquid, sealing, reacting in an oven at 240 ℃ for 36 hours, taking out the reaction kettle after the reaction is finished, and quickly cooling to room temperature to obtain the solution containing the bismuth telluride nanosheet solution. Respectively centrifugally cleaning the solution by deionized water and absolute ethyl alcohol for 3 times, dissolving the product in 50ml of deionized water, and continuously magnetically stirring at room temperature for the next step;

0.2g (ca. 0.48mmol) of tetrachloroauric acid (HAuCl) was weighed out₄·4H₂O), dissolved in 5ml of deionized water and gently shaken to completely dissolve. And (3) slowly adding 5ml of solution into the stirred bismuth telluride nanosheet solution in batches by using a liquid transfer gun, wherein 0.5ml of solution is added each time. After all the solution was added, the mixed solution was magnetically stirred at room temperature for 0.5h, and then the solution was taken out and washed 3 times with deionized water and absolute ethanol each by centrifugation. Placing the centrifuged product in a vacuum oven for drying at 50 ℃ to obtain black powder, namely the bismuth telluride nanosheets with gold nanoparticles loaded on the surfaces;

the obtained product was sintered into a sample of a flake having a diameter of 12.7mm and a thickness of 2mm by plasma activated sintering 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 sheet samples was tested using laser photothermal methods.

Referring to fig. 1, it can be found that the product obtained in step 1 is a regular hexagonal two-dimensional lamellar structure, and has uniform size, good dispersibility and no obvious impurities. The sides of the hexagonal lamellae are about 200nm (FIG. 1 (a)). The phase of the product was found to match the diffraction peak position of the Bi2Te3 crystal by XRD spectrum analysis, indicating that the resulting product was a well-crystallized Bi2Te3 nanosheet (fig. 1 (b)).

Example 2

0.97g (2mmol) of Bi (NO)₃)₃·5H₂O，0.664g(3mmol)Na₂TeO₃Dissolving 4g (10mmol) of NaOH in 80ml of ethylene glycol, heating to 80 ℃ under the action of magnetic stirring, transferring the solution to 100 after the milky suspension is changed into colorless transparent liquidSealing the reaction kettle in ml, reacting for 36h in an oven at 240 ℃, taking out the reaction kettle after the reaction is finished, and quickly cooling to room temperature to obtain the solution containing the bismuth telluride nanosheet solution. Respectively centrifugally cleaning the solution by deionized water and absolute ethyl alcohol for 3 times, dissolving the product in 50ml of deionized water, and continuously magnetically stirring at room temperature for the next step;

0.4g (0.96mmol) of tetrachloroauric acid (HAuCl) was weighed₄·4H₂O), dissolved in 10ml of deionized water and gently shaken to completely dissolve. And (3) slowly adding 10ml of solution into the stirred bismuth telluride nanosheet solution in batches by using a liquid transfer gun, wherein 1ml of solution is added each time. After all the solution was added, the mixed solution was magnetically stirred at room temperature for 1 hour, and then the solution was taken out and washed 3 times by centrifugation with deionized water and absolute ethanol, respectively. Placing the centrifuged product in a vacuum oven for drying at 50 ℃ to obtain black powder, namely the bismuth telluride nanosheets with gold nanoparticles loaded on the surfaces;

the obtained product was sintered into a sample of a flake having a diameter of 12.7mm and a thickness of 2mm by plasma activated sintering 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 sheet samples was tested using laser photothermal methods.

Comparing fig. 2 and fig. 3, it can be found that the gold particles supported on the nanosheet surface significantly increase with the increase of the addition amount of tetrachloroauric acid.

FIG. 4 shows Au particles combined with Bi₂Te₃And (5) the microstructure of the nanosheet is characterized. Regular Bi can be seen from low-power TEM image₂Te₃And the size of the hexagonal lamellar structure is consistent with that of the SEM image. High-density Au particles are attached to the surface and the edge of the sheet layer. The size of Au particles is about 5nm, and the crystal lattice fringes are clear. The interplanar spacing is 0.225nm and corresponds to the (111) crystal face of Au; bi₂Te₃The interplanar spacing of the nanosheet is 0.217nm, corresponding to Bi₂Te₃The (110) crystal plane of (a). The surface scanning of the elements in the local area shows that Au, Bi and Te are uniformly distributed on the surface of the nanosheet, and the element segregation does not exist. EDS characterization results show that the atomic ratio of Au to Bi to Te is about 24:35: 41.

FIG. 5 shows Au/Bi₂Te₃The XRD pattern of the nano-sheet can see that all diffraction peaks of the two samples correspond to the hexagonal Bi₂Te₃And the standard spectral line of cubic Au crystals. The particles attached to the surfaces of the nanosheets are further proved to be crystalline Au particles. The relative intensity of the diffraction peak of the Au particle increases with the increase of the concentration of the Au atom, which indicates that the number of the Au particles in the crystalline state also increases.

Fig. 6 shows the comparison of the thermal conductivity of the product obtained in examples 1 and 2 with that of bismuth telluride nanosheets measured according to the temperature change. ) The thermal conductivity of each sample increased slightly with increasing temperature. Wherein Bi of pure phase₂Te₃The thermal conductivity of the nano sheet is the highest and is 1 W.m^-1·K^-1Left and right. Au/Bi in examples 1 and 2₂Te₃The thermal conductivity of the nano composite structure is lower than that of Bi₂Te₃About 40% of the nanoplatelets. Showing that Au particles modify Bi₂Te₃Has obvious reduction effect on the thermal conductivity of the material.

Example 3

0.97g (2mmol) of Bi (NO)₃)₃·5H₂O，0.664g(3mmol)Na₂TeO₃Dissolving 4g (10mmol) of NaOH in 80ml of ethylene glycol, heating to 80 ℃ under the action of magnetic stirring, transferring the solution to a 100ml reaction kettle after the solution is changed into colorless transparent liquid from milky suspension, sealing, reacting in an oven at 240 ℃ for 36h, taking out the reaction kettle after the reaction is finished, and quickly cooling to room temperature to obtain the solution containing the bismuth telluride nanosheet solution. Respectively centrifugally cleaning the solution by deionized water and absolute ethyl alcohol for 3 times, dissolving the product in 50ml of deionized water, and continuously magnetically stirring at room temperature for the next step;

0.4mmol of tetrachloroauric acid (HAuCl) was weighed₄·4H₂O), dissolved in 10ml of deionized water and gently shaken to completely dissolve. And (3) slowly adding 10ml of solution into the stirred bismuth telluride nanosheet solution in batches by using a liquid transfer gun, wherein 1ml of solution is added each time. After all the solution was added, the mixed solution was magnetically stirred at room temperature for 0.5h, and then the solution was taken out and washed 3 times with deionized water and absolute ethanol each by centrifugation. Placing the centrifuged product inAnd drying in a vacuum oven at 50 ℃ to obtain black powder, namely the bismuth telluride nanosheet with gold nanoparticles loaded on the surface.

Example 4

0.97g (2mmol) of Bi (NO)₃)₃·5H₂O，0.664g(3mmol)Na₂TeO₃Dissolving 4g (10mmol) of NaOH in 80ml of ethylene glycol, heating to 80 ℃ under the action of magnetic stirring, transferring the solution to a 100ml reaction kettle after the solution is changed into colorless transparent liquid from milky suspension, sealing, reacting in an oven at 240 ℃ for 36h, taking out the reaction kettle after the reaction is finished, and quickly cooling to room temperature to obtain the solution containing the bismuth telluride nanosheet solution. Respectively centrifugally cleaning the solution by deionized water and absolute ethyl alcohol for 3 times, dissolving the product in 50ml of deionized water, and continuously magnetically stirring at room temperature for the next step;

0.5mmol of tetrachloroauric acid (HAuCl) was weighed₄·4H₂O), dissolved in 10ml of deionized water and gently shaken to completely dissolve. And (3) slowly adding 10ml of solution into the stirred bismuth telluride nanosheet solution in batches by using a liquid transfer gun, wherein 1ml of solution is added each time. After all the solution was added, the mixed solution was magnetically stirred at room temperature for 0.6h, and then the solution was taken out and washed 3 times with deionized water and absolute ethanol each by centrifugation. And (3) drying the centrifuged product in a vacuum oven at 50 ℃ to obtain black powder, namely the bismuth telluride nanosheet with the gold nanoparticles loaded on the surface.

Example 5

0.97g (2mmol) of Bi (NO)₃)₃·5H₂O，0.664g(3mmol)Na₂TeO₃Dissolving 4g (10mmol) of NaOH in 80ml of ethylene glycol, heating to 80 ℃ under the action of magnetic stirring, transferring the solution to a 100ml reaction kettle after the solution is changed into colorless transparent liquid from milky suspension, sealing, reacting in an oven at 240 ℃ for 36h, taking out the reaction kettle after the reaction is finished, and quickly cooling to room temperature to obtain the solution containing the bismuth telluride nanosheet solution. Respectively centrifugally cleaning the solution by deionized water and absolute ethyl alcohol for 3 times, dissolving the product in 50ml of deionized water, and continuously magnetically stirring at room temperature for the next step;

0 is weighed out.6mmol of tetrachloroauric acid (HAuCl)₄·4H₂O), dissolved in 10ml of deionized water and gently shaken to completely dissolve. And (3) slowly adding 10ml of solution into the stirred bismuth telluride nanosheet solution in batches by using a liquid transfer gun, wherein 1ml of solution is added each time. After all the solution was added, the mixed solution was magnetically stirred at room temperature for 0.7h, and then the solution was taken out and washed 3 times with deionized water and absolute ethanol each by centrifugation. And (3) drying the centrifuged product in a vacuum oven at 50 ℃ to obtain black powder, namely the bismuth telluride nanosheet with the gold nanoparticles loaded on the surface.

Example 6

0.97g (2mmol) of Bi (NO)₃)₃·5H₂O，0.664g(3mmol)Na₂TeO₃Dissolving 4g (10mmol) of NaOH in 80ml of ethylene glycol, heating to 80 ℃ under the action of magnetic stirring, transferring the solution to a 100ml reaction kettle after the solution is changed into colorless transparent liquid from milky suspension, sealing, reacting in an oven at 240 ℃ for 36h, taking out the reaction kettle after the reaction is finished, and quickly cooling to room temperature to obtain the solution containing the bismuth telluride nanosheet solution. Respectively centrifugally cleaning the solution by deionized water and absolute ethyl alcohol for 3 times, dissolving the product in 50ml of deionized water, and continuously magnetically stirring at room temperature for the next step;

0.7mmol of tetrachloroauric acid (HAuCl) was weighed₄·4H₂O), dissolved in 10ml of deionized water and gently shaken to completely dissolve. And (3) slowly adding 10ml of solution into the stirred bismuth telluride nanosheet solution in batches by using a liquid transfer gun, wherein 1ml of solution is added each time. After all the solution was added, the mixed solution was magnetically stirred at room temperature for 0.75h, and then the solution was taken out and washed 3 times with deionized water and absolute ethanol each by centrifugation. And (3) drying the centrifuged product in a vacuum oven at 50 ℃ to obtain black powder, namely the bismuth telluride nanosheet with the gold nanoparticles loaded on the surface.

Example 7

0.97g (2mmol) of Bi (NO)₃)₃·5H₂O，0.664g(3mmol)Na₂TeO₃Dissolving 4g (10mmol) of NaOH in 80ml of ethylene glycol, heating to 80 ℃ under the action of magnetic stirring, and after the solution is changed from milky suspension into colorless transparent liquid,transferring the bismuth telluride nano-sheet into a 100ml reaction kettle, sealing, reacting in an oven at 240 ℃ for 36h, taking out the reaction kettle after the reaction is finished, and rapidly cooling to room temperature to obtain the solution containing the bismuth telluride nano-sheet solution. Respectively centrifugally cleaning the solution by deionized water and absolute ethyl alcohol for 3 times, dissolving the product in 50ml of deionized water, and continuously magnetically stirring at room temperature for the next step;

weighing 0.8mmol of tetrachloroauric acid (HAuCl)₄·4H₂O), dissolved in 10ml of deionized water and gently shaken to completely dissolve. And (3) slowly adding 10ml of solution into the stirred bismuth telluride nanosheet solution in batches by using a liquid transfer gun, wherein 1ml of solution is added each time. After all the solution was added, the mixed solution was magnetically stirred at room temperature for 0.8h, and then the solution was taken out and washed 3 times with deionized water and absolute ethanol each by centrifugation. And (3) drying the centrifuged product in a vacuum oven at 50 ℃ to obtain black powder, namely the bismuth telluride nanosheet with the gold nanoparticles loaded on the surface.

Example 8

0.97g (2mmol) of Bi (NO)₃)₃·5H₂O，0.664g(3mmol)Na₂TeO₃Dissolving 4g (10mmol) of NaOH in 80ml of ethylene glycol, heating to 80 ℃ under the action of magnetic stirring, transferring the solution to a 100ml reaction kettle after the solution is changed into colorless transparent liquid from milky suspension, sealing, reacting in an oven at 240 ℃ for 36h, taking out the reaction kettle after the reaction is finished, and quickly cooling to room temperature to obtain the solution containing the bismuth telluride nanosheet solution. Respectively centrifugally cleaning the solution by deionized water and absolute ethyl alcohol for 3 times, dissolving the product in 50ml of deionized water, and continuously magnetically stirring at room temperature for the next step;

0.9mmol of tetrachloroauric acid (HAuCl) was weighed₄·4H₂O), dissolved in 10ml of deionized water and gently shaken to completely dissolve. And (3) slowly adding 10ml of solution into the stirred bismuth telluride nanosheet solution in batches by using a liquid transfer gun, wherein 1ml of solution is added each time. After all the solution was added, the mixed solution was magnetically stirred at room temperature for 0.9h, and then the solution was taken out and washed 3 times with deionized water and absolute ethanol each by centrifugation. Drying the centrifuged product in a vacuum oven at 50 ℃ to obtain black powderIs a bismuth telluride nano-sheet with gold nano-particles loaded on the surface.

Example 9

0.97g (2mmol) of Bi (NO)₃)₃·5H₂O，0.664g(3mmol)Na₂TeO₃Dissolving 4g (10mmol) of NaOH in 80ml of ethylene glycol, heating to 80 ℃ under the action of magnetic stirring, transferring the solution to a 100ml reaction kettle after the solution is changed into colorless transparent liquid from milky suspension, sealing, reacting in an oven at 240 ℃ for 36h, taking out the reaction kettle after the reaction is finished, and quickly cooling to room temperature to obtain the solution containing the bismuth telluride nanosheet solution. Respectively centrifugally cleaning the solution by deionized water and absolute ethyl alcohol for 3 times, dissolving the product in 50ml of deionized water, and continuously magnetically stirring at room temperature for the next step;

1mmol of tetrachloroauric acid (HAuCl) was weighed₄·4H₂O), dissolved in 10ml of deionized water and gently shaken to completely dissolve. And (3) slowly adding 10ml of solution into the stirred bismuth telluride nanosheet solution in batches by using a liquid transfer gun, wherein 1ml of solution is added each time. After all the solution was added, the mixed solution was magnetically stirred at room temperature for 1 hour, and then the solution was taken out and washed 3 times by centrifugation with deionized water and absolute ethanol, respectively. And (3) drying the centrifuged product in a vacuum oven at 50 ℃ to obtain black powder, namely the bismuth telluride nanosheet with the gold nanoparticles loaded on the surface.

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.