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Method for quickly preparing monoclinic phase VO2

A technology of VO2 and monoclinic phase, applied in the direction of vanadium oxide, etc., can solve problems such as difficulty in obtaining VO2 pure phase, increase in preparation cost, and difficulty in controlling the valence state of vanadium

Inactive Publication Date: 2013-12-18
UNIV OF SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method requires expensive cost and it is difficult to control the valence state of vanadium in it, and it is difficult to obtain VO 2 pure phase
This makes the monoclinic and tetragonal rutile vanadium dioxide (VO 2 (M) and VO 2 (R)) The preparation cost of the powder is greatly increased, and it is difficult to achieve large-scale production

Method used

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  • Method for quickly preparing monoclinic phase VO2
  • Method for quickly preparing monoclinic phase VO2
  • Method for quickly preparing monoclinic phase VO2

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Embodiment 1: with VO 2 (B) Preparation of VO 2 (M)

[0044] 1) In a polytetrafluoroethylene reactor with a volume of 50mL, add 2mmol V 2 o 5 and 40 mL of distilled water, and adjust the pH value to 3-4 with 10% HCOOH aqueous solution. After stirring for 30 minutes, put it into a kettle shell and seal it, then keep it at 200°C for 12 hours, and after natural cooling, collect the product by centrifugation to obtain VO 2 (B).

[0045] 2) Will contain 0.5g VO 2 (B) The porcelain boat is placed with N 2in a tube furnace, and annealed at 450°C for 12h, and after cooling, VO with a purity of 100% was obtained 2 (M). The XRD spectrum and DSC cycle spectrum of this compound and Figure 4 and Figure 5 No substantial differences are shown. It can be seen from the figure that the structure of the compound is correct.

Embodiment 2

[0046] Embodiment 2: use phase A VO 2 (A) Preparation of VO 2 (M)

[0047] 1) Add 2mmol VO(acac) to a polytetrafluoroethylene reactor with a volume of 50ml 2 (Vanadium acetylacetonate complex) and 40mL of distilled water, and adjust the pH value to 3-4 with a 10% HCOOH aqueous solution by mass percentage, after stirring for 30min, put it into a kettle shell and seal it, and then keep it at 220°C for 12h. After natural cooling, the product was collected by centrifugation to obtain phase A VO 2 (A).

[0048] 2) Will contain 0.5g VO 2 The porcelain boat of (A) is placed through the N 2 in a tube furnace, and annealed at 450°C for 12h, and after cooling, VO with a purity of 100% was obtained 2 (M). The XRD spectrum and DSC cycle spectrum of this compound and Figure 4 and Figure 5 No substantial differences are shown. It can be seen from the figure that the structure of the compound is correct.

Embodiment 3

[0049] Embodiment 3: with VO 2 (P) Preparation of VO 2 (M)

[0050] 1) In a polytetrafluoroethylene reactor with a volume of 50ml, add 4mmol Na 3 VO 4 12H 2 O (sodium orthovanadate), 20mmol TAA (thioacetamide) and 50ml distilled water, after stirring for 30min, put them into the kettle shell, then keep at 200°C for 12h, after natural cooling, centrifuge to collect the product to obtain VO 2 (P), the XRD spectrum of this compound is as figure 1 shown. It can be seen from the figure that the structure of the compound is correct.

[0051] 2) Will contain 0.5g VO 2 The porcelain boat of (P) is placed with N 2 in a tube furnace, and annealed at 400°C for 1 minute, and after cooling, VO with a purity of 100% was obtained 2 (M). The compound VO 2 The XRD spectrum and DSC cycle spectrum of (M) are respectively Figure 4 and Figure 5 shown. It can be seen from the figure that the structure of the compound is correct.

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Abstract

The invention discloses a method for quickly preparing monoclinic phase VO2. In the method, metastable phase reactant containing vanadium or VOOH reactant reacts for 1 minute to 12 hours at the temperature of 200-500 DEG C in the atmosphere of inert gases or inert gases doped with oxygen, and the monoclinic phase VO2 is obtained after cooling. The method can quickly convert the metastable phase reactant containing vanadium or VOOH into the monoclinic phase VO2 under the protection of normal-pressure inert atmosphere. The method has simple technology, low cost, high yield and favorable purity and can quickly prepare the intelligent energy-saving monoclinic phase VO2 powder on a large scale.

Description

technical field [0001] The invention relates to the preparation of monoclinic phase and tetragonal rutile phase vanadium dioxide powder, in particular to a method for rapidly preparing monoclinic phase VO 2 Methods. Background technique [0002] Vanadyl oxide is a very important class of materials with intelligent properties. Changes in ambient temperature will cause changes in the crystal structure, electric domain structure, and magnetic structure of the material, resulting in large changes in optical properties. Especially vanadium dioxide (VO 2 ) has received special attention. [0003] Monoclinic VO 2 (referred to as VO 2 (M)) and tetragonal rutile phase VO 2 (referred to as VO 2 (R)) powder can be intelligently regulated to the outside world, such as the infrared part of sunlight, through phase change to achieve intelligent energy saving. Single crystal VO 2 The metal-insulator phase transition temperature is 68°C. At this temperature, VO 2 The crystal struct...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G31/02
Inventor 吴长征张晓东谢毅
Owner UNIV OF SCI & TECH OF CHINA
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