Technique for preparing phase-change temperature controllable tungsten doping nano vanadium dioxide powder

A technology of vanadium dioxide and phase transition temperature, applied in vanadium oxide, heat exchange materials, chemical instruments and methods, etc., can solve the problems of ineffective doping, low activity of tungsten source, difficult to control phase transition temperature, etc. , to achieve the effect of increased doping amount and controllable phase transition temperature

Inactive Publication Date: 2008-04-23
SHANGHAI NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Although in Chinese patent documents CN1279211, CN1347856, CN1451633, CN1693211, CN1693212, the preparation process of doped nano-vanadium dioxide powder is disclosed, especially the preparation process of tungsten-doped nano-vanadium dioxide powder, but they all have common Disadvantages: The doped tungsten source has low activity and cannot be effectively doped to VO 2 lattice, so it is difficult to achieve phase transition temperature controllable

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] The preparation process of tungsten-doped nano-vanadium dioxide powder with controllable phase transition temperature in this embodiment includes the following specific steps:

[0024] 1) Prepare 0.5mol / L of V with deionized water 2 o 5 solution;

[0025] 2) Add dropwise oxalic acid to adjust pH=7~9;

[0026] 3) stirring at 70-90°C for 0.5-1.5 hours;

[0027] 4) Add concentrated hydrochloric acid dropwise three times to keep the pH of the reaction system at 7-9;

[0028] 5) Stir at 100°C for 15 minutes;

[0029] 6) Add dropwise 6ml of organic amine-formic acid (molar ratio: 1:2) solution, so that the reaction solution is dark blue, that is, VOCl 2 solution;

[0030] 7) Dilute to 2.0mol / L with deionized water, then use V 2 o 5 adjust pH = 1;

[0031] 8) Prepare 2mol / L NH with deionized water 4 HCO 3 solution and then added with NH 4 HCO 3 Equimolar white tungstic acid, carbon dioxide is introduced to drive oxygen;

[0032] 9) Add 30ml of the above VOCl drop...

Embodiment 2

[0038] The preparation process of tungsten-doped nano-vanadium dioxide powder with controllable phase transition temperature in this embodiment includes the following specific steps:

[0039] 1) Prepare 1mol / L of V with deionized water 2 o 5 solution;

[0040] 2) Add dropwise oxalic acid to adjust pH=7~9;

[0041] 3) stirring at 70-90°C for 0.5-1.5 hours;

[0042] 4) Add concentrated hydrochloric acid dropwise three times to keep the pH of the reaction system at 7-9;

[0043] 5) Stir at 100°C for 15 minutes;

[0044] 6) Add 8ml of organic amine-formic acid (molar ratio: 1:2) solution dropwise, so that the reaction solution turns dark blue to obtain VOCl 2 solution;

[0045] 7) Dilute to 2.0mol / L with deionized water, then use V 2 o 5 adjust pH = 1;

[0046] 8) Prepare 1.5mol / L NH with deionized water 4 HCO 3 solution and then added with NH 4 HCO 3 Equimolar white tungstic acid, carbon dioxide is introduced to drive oxygen;

[0047] 9) Add 50ml of the above VOCl d...

Embodiment 3

[0053] The preparation process of tungsten-doped nano-vanadium dioxide powder with controllable phase transition temperature in this embodiment includes the following specific steps:

[0054] 1) Prepare 0.75mol / L of V with deionized water 2 o 5 solution;

[0055] 2) Add dropwise oxalic acid to adjust pH=7~9;

[0056] 3) stirring at 70-90°C for 0.5-1.5 hours;

[0057] 4) Add concentrated hydrochloric acid dropwise three times to keep the pH of the reaction system at 7-9;

[0058] 5) Stir at 100°C for 15 minutes;

[0059] 6) Add dropwise 7ml of organic amine-formic acid (molar ratio 1:2) solution to make the reaction solution dark blue to obtain VOCl 2 solution;

[0060] 7) Dilute to 2.0mol / L with deionized water, then use V 2 o 5 adjust pH = 1;

[0061] 8) Prepare 1.75mol / L NH with deionized water 4 HCO 3 solution and then added with NH 4 HCO 3 Equimolar white tungstic acid, carbon dioxide is introduced to drive oxygen;

[0062] 9) Add 40ml of the above VOCl dropwis...

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Abstract

This invention discloses a method for preparing controllable phase-transformation and tungsten-doped vanadium dioxide powder. In this invention, controlled, strictly, is the pH value (being at 7-9) of the solution for preparing prodecessor; selected is combined reductant containing organic amine and formic acid; protected by inert gas during whole process. By using this inventive method, obtained is high pureness single-phase VO2 nanometer powder. Due to the activity of white tungstic acid is far higher than that of other tungsten compounds, the adulteration of W6+ in VO2 crystal lattice is increased greatly, to achieve the effective adulteration, and then to realize controllable phase transformation temperature.

Description

technical field [0001] The invention relates to a preparation process of nano vanadium dioxide powder, in particular to a preparation process of tungsten-doped nano vanadium dioxide powder with controllable phase transition temperature. Background technique [0002] As a functional material, vanadium dioxide (VO 2 ) Since the thermally induced phase transition, VO 2 It has become a kind of thermotaxis currently researched in phase change metal compounds. The reason is that VO 2 The phase transition temperature is 68°C, which is closest to room temperature, that is, VO 2 The high-temperature metal phase (M) and low-temperature semiconductor phase (S) will undergo a sudden change at 68°C. With the change of structure, VO 2 Certain physical properties of certain materials will also undergo sudden changes, such as a 4-5 order of magnitude jump in resistance (rate), as well as sudden changes in magnetic susceptibility, optical refractive index, transmittance, and reflectance...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G31/02C09K5/02
Inventor 彭子飞江炜王媛
Owner SHANGHAI NORMAL UNIVERSITY
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