CN1526638A

CN1526638A - Prepn of Bi2Te3-base nano thermoelectric material powder containing RE element

Info

Publication number: CN1526638A
Application number: CNA031512755A
Authority: CN
Inventors: 赵新兵; 吉晓华; 张艳华
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2003-09-25
Filing date: 2003-09-25
Publication date: 2004-09-08
Anticipated expiration: 2023-09-25
Also published as: CN1267338C

Abstract

The present invention discloses the preparation process of Bi2Te3-base nano thermoelectric material powder containing RE element. The simple substance or compound of Sb and/or Bi elements, Se and/or Te elements and/or the simple substance or compound of doping element are RE element compound in certain proportion are mixed in deionized water or organic solvent, sufficient reductant is added, and the mixture is sealed inside high-pressure reactor for reaction at 100-300 deg.c of 6-50 hr. Through subsequent cooling, washing and drying, Bi2Te3-base nano thermoelectric material powder containing RE element with average grain size below 40 nm is obtained. The said process is simple, low in cost, low in synthesis temperature, short in period, high in product purity and small in product granularity. In addition, the nano material has raised thermoelectric performance.

Description

The Bi that contains rare earth element 2Te 3The preparation method of base thermoelectricity material nano powder

Technical field

The present invention relates to a kind of preparation method of thermoelectric material.Specifically, be about containing the Bi of rare earth element ₂Te ₃The preparation method of base thermoelectricity material nano powder.

Background technology

The Bi that contains rare earth element ₂Te ₃Base thermoelectricity material because the peculiar f layer of rare earth element electron energy band has bigger virtual mass, helps to improve the thermoelectric (al) power factor (α of material ²σ); Simultaneously, the hydridization effect between the d electronics of f layer electronics and other element can form a kind of complicated energy band structure that is called as middle valence state (intermediatevalence state), thereby may obtain the Bi of the high figure of merit ₂Te ₃Base thermoelectricity material.At present, preparation contains the Bi of rare earth element ₂Te ₃Base thermoelectricity material adopts the mechanical alloying method, this method complex process, and the production cycle is long, and to the ingredient requirement height, efficient is low.

Summary of the invention

The preparation of the purpose of this invention is to provide that a kind of technology is easy, cost is low, the cycle is short contains the Bi of rare earth element ₂Te ₃The method of base thermoelectricity material nano powder.

The Bi that contains rare earth element of the present invention ₂Te ₃The preparation method of base thermoelectricity material nano powder adopts the hydrothermal/solvent by the use of thermal means, may further comprise the steps:

1) with Sb or/and Bi element and Se or/and the simple substance of the simple substance of Te element or compound and/or doped element or compound and rare-earth compound, in deionized water or organic solvent, the component and the content of final product are as follows according to the determined mixed of final product chemical ingredients: in Sb or/and Bi and Se or/and Te element atomic ratio is p type or the n type Bi that 1.9～2.1: 2.9～3.1 ratio forms ₂Te ₃Based compound accounts for 85～98% of material total atom per-cent, and the rare earth element atom accounts for 2～10% of material total atom per-cent, and one or more among doped element atom Sn, Pb, I, Br, Al or the Li account for 0～5% of material total atom per-cent;

2) above-mentioned mixed solution is placed in the reaction vessel of autoclave, add the reductive agent of capacity, then sealing immediately;

3) certain temperature and 6～50 hours postcooling of insulation reaction that reaction vessel is warming up in 100～300 ℃ of scopes arrives room temperature;

4) collect the interior solid reaction product of reaction vessel, repeatedly clean after drying, obtain material of the present invention through deionized water, organic solvent and/or dilute acid soln.

Above-mentioned rare earth element can be one or more elements in 57～No. 71 La～Lu elements in the periodic table of elements.

Said Sb or/and Bi element and Se or/and the compound of Te element can be muriate, oxide compound, nitrate, vitriol or carbonate etc.

The compound of said rare earth element and doped element can be muriate, oxide compound, nitrate, vitriol or carbonate etc.

Above-mentioned steps 1) said organic solvent can be ethanol, acetone, N in, dinethylformamide, pyridine, quadrol, benzene or toluene etc.Step 2) said reductive agent can adopt NaBH in ₄, KBH ₄Etc. alkali-metal hydroborates or basic metal such as metal Na, K.Said organic solvent can be ethanol, acetone or tetracol phenixin etc. in the step 4).

The Bi that contains rare earth element that adopts the inventive method to make ₂Te ₃The base thermoelectricity material nanometer powder is the nano particle of the sphere of characteristic dimension below 100nm, polyhedron, laminar, needle-like, tubulose form.

The rare earth element Bi that contains of the present invention ₂Te ₃The hydrothermal/solvent hot preparation method of base thermoelectricity material nano powder is a kind of novel preparation method of nano material.This method has advantages such as technology is easy, cost is low, synthesis temperature is low, the cycle is short, product purity is high, granularity is little.This method particle nanometer of making material has also further improved the thermoelectricity capability of material in addition.

Embodiment

Below in conjunction with embodiment the present invention is done further to state in detail.

Embodiment 1

1) with analytical pure BiCl ₃, the high purity tellurium powder (＞99.99wt%), and in Bi: 2: 3 ratio of Te atomic percent batching, and be that 10% ratio takes by weighing analytical pure LaCl in the atom content per-cent of La ₃, be mixed in the dehydrated alcohol;

2) mixed solution for preparing is placed the reaction vessel (the filling degree is 80%) of autoclave (WDF-0.25 type), and in solution, add reductive agent NaBH ₄, sealing immediately then;

3) with reaction vessel heat temperature raising to 180 ℃ and be incubated 12 hours.

4) reaction naturally cools to room temperature after finishing, and collects the Powdered reaction product at the bottom of the still, clean several repeatedly with deionized water, dehydrated alcohol and acetone successively after, powder is got final product at 100 ℃ of following vacuum-drying 6h.

Through chemical analysis, the La constituent content in this synthetic product is 9.05%.

Embodiment 2

1) raw material: analytical pure BiCl ₃, the high purity tellurium powder (＞99.99wt%), analytical pure Er ₂O ₃In Bi: 2: 3 ratio of Te atomic ratio batching, and be that 10% ratio takes by weighing analytical pure Er in Er atom content per-cent ₂O ₃

2) above-mentioned raw materials is mixed among the organic solvent DMF after the weighing respectively in proportion, and in solution, adds an amount of reductive agent NaBH ₄The solution for preparing is placed the reaction vessel (the filling degree is 80%) of autoclave (WDF-0.25 type).

3) with the slow heat temperature raising to 150 ℃ and be incubated 24 hours in reaction vessel sealing back.In the insulation reaction process, the autogenous pressure of reaction vessel interior is about 3.5MPa.

4) reaction naturally cools to room temperature after finishing, and the Powdered reaction product at the bottom of the still is collected in step-down, clean several repeatedly with 1% dilute hydrochloric acid, deionized water, dehydrated alcohol and acetone successively after, powder is got final product at 100 ℃ of following vacuum-drying 6h.

Through chemical analysis, the Er constituent content in this synthetic product is 8.56%.

Embodiment 3

1) with analytical pure BiCl ₃, the high purity tellurium powder (＞99.99wt%) in Bi: the Te atomic percent is 2: 3 a ratio batching, and takes by weighing LaCl in the ratio that La and Sn atom content per-cent account for all raw material total amounts 8% and 2% respectively ₃And SnCl ₂

2) all raw materials are mixed in the dehydrated alcohol, place the reaction vessel (the filling degree is 80%) of autoclave (WDF-0.25 type), and add reductive agent KBH ₄, sealing immediately then;

3) with reaction vessel heat temperature raising to 180 ℃ and be incubated 6 hours.

Through chemical analysis, the La constituent content in this synthetic product is 6.96%.

Embodiment 4

1) raw material: analytical pure BiNO ₃, the high purity tellurium powder (＞99.99wt%), analytical pure Sm ₂O ₃In Bi: 2: 3 ratio of Te atomic ratio batching, and be that 10% ratio takes by weighing analytical pure Sm in Sm atom content per-cent ₂O ₃All raw materials are mixed in the acetone;

3) with reaction vessel heat temperature raising to 120 ℃ and be incubated 48 hours.

Through chemical analysis, the Sm constituent content in the above-mentioned synthetic product is 8.88%.

Adopt the granular size and the microscopic appearance of JEM-2010 (HR) type transmission electron microscope observation solvent thermal synthetic product powdered sample.The result shows, all product powder of the foregoing description are the nano particle of the following sphere of median size 40nm, polyhedron, laminar, needle-like, tubulose form.

Claims

1. Bi who contains rare earth element ₂Te ₃The preparation method of base thermoelectricity material nano powder is characterized in that may further comprise the steps:

2) above-mentioned mixed solution is placed in the reaction vessel of autoclave, add reductive agent, then sealing immediately;

2. the Bi that contains rare earth element according to claim 1 ₂Te ₃The preparation method of base thermoelectricity material nano powder is characterized in that said rare earth element is one or more elements in 57～No. 71 La～Lu elements in the periodic table of elements.

3. the Bi that contains rare earth element according to claim 1 ₂Te ₃The preparation method of base thermoelectricity material nano powder, it is characterized in that said Sb or/and Bi element and Se or/and the compound of Te element is muriate, oxide compound, nitrate, vitriol or carbonate.

4. the Bi that contains rare earth element according to claim 1 ₂Te ₃The preparation method of base thermoelectricity material nano powder, the compound that it is characterized in that said rare earth element and doped element is muriate, oxide compound, nitrate, vitriol or carbonate.

5. the Bi that contains rare earth element according to claim 1 ₂Te ₃The preparation method of base thermoelectricity material nano powder is characterized in that said organic solvent is ethanol, acetone, N in the step 1), dinethylformamide, pyridine, quadrol, benzene or toluene.

6. the Bi that contains rare earth element according to claim 1 ₂Te ₃The preparation method of base thermoelectricity material nano powder is characterized in that step 2) in said reductive agent be NaBH ₄, KBH ₄Alkali-metal hydroborates or metal Na, K basic metal.

7. the Bi that contains rare earth element according to claim 1 ₂Te ₃The preparation method of base thermoelectricity material is characterized in that said organic solvent is ethanol, acetone or tetracol phenixin in the step 4).

8. the Bi that contains rare earth element according to claim 1 ₂Te ₃The preparation method of base thermoelectricity material nano powder is characterized in that the prepared Bi that contains rare earth element ₂Te ₃The base thermoelectricity material nano powder is a characteristic dimension at the nano particle of the sphere of 5～100nm, polyhedron, laminar, needle-like, tubulose form.