Method for preparing hollow spheres and films surrounded by VO2 nanosheets

A nanosheet and VO2 technology, applied in the direction of vanadium oxide, etc., can solve the problems of difficult preparation of particles, low sensitivity, large hysteresis width of small particles, etc., and achieve balance of visible light transmittance and light modulation ability, and enhanced sensitivity Effect

Inactive Publication Date: 2018-07-20
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Experimental and calculation results show that small particle size can improve the optical properties of the film. At present, the minimum size can reach 20-30nm, but it is difficult to prepare particles smaller than 20nm, and small particles are prone to serious aggregation. In addition, the hysteresis of small particles The width is usually large, i.e. the sensitivity is low

Method used

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  • Method for preparing hollow spheres and films surrounded by VO2 nanosheets
  • Method for preparing hollow spheres and films surrounded by VO2 nanosheets
  • Method for preparing hollow spheres and films surrounded by VO2 nanosheets

Examples

Experimental program
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Effect test

Embodiment 1

[0052] 1) Configure a mixed solution of ethanol and deionized water with a volume ratio of 4:1, and add ammonium metavanadate, the concentration of ammonium metavanadate in the solution is 0.05mol / L; crush the mixed solution with a cell pulverizer, and make The vanadium precursor is fully dissolved in the mixed solution to obtain solution A;

[0053] 2) After adding ethylene glycol, stir magnetically until the solution is uniform, the volume of ethylene glycol accounts for 3% of the volume of mixed solution A, add oxalic acid (H 2 C 2 o 4 ), the concentration of oxalic acid in the solution is 0.1mol / L, continue to stir until the reaction is sufficient, transfer it to a high-pressure reactor lined with polytetrafluoroethylene for hydrothermal reaction, the filling degree is 70%, and the hydrothermal reaction is carried out at 200 ° C 24h, natural cooling, obtain the reaction solution, pour out the supernatant in the reaction solution, obtain the reactant;

[0054] 3) Wash th...

Embodiment 2

[0060] 1) Configure a mixed solution of ethanol and deionized water with a volume ratio of 3:1, and add ammonium metavanadate, and the concentration of ammonium metavanadate in the solution is 0.025mol / L; crush the mixed solution with a cell pulverizer to make The vanadium precursor is fully dissolved in the mixed solution to obtain solution A;

[0061] 2) After adding ethylene glycol, stir magnetically until the solution is uniform, the volume of ethylene glycol accounts for 5% of the volume of the mixed solution A, add oxalic acid (H 2 C 2 o 4 ), the concentration of oxalic acid in the solution is 0.064mol / L, continue to stir until the reaction is fully transferred to a high-pressure reactor lined with polytetrafluoroethylene for hydrothermal reaction, the filling degree is 60%, hydrothermal reaction at 190 ° C 26h, natural cooling to obtain the reaction solution, pouring out the supernatant in the reaction solution to obtain the reactant;

[0062] 3) Wash the reactant th...

Embodiment 3

[0067] 1) Configure a mixed solution of ethanol and deionized water with a volume ratio of 2:1, and add ammonium metavanadate, the concentration of ammonium metavanadate in the solution is 0.03mol / L; use a cell pulverizer to pulverize the mixed solution to make The vanadium precursor is fully dissolved in the mixed solution to obtain solution A;

[0068] 2) After adding ethylene glycol, stir magnetically until the solution is uniform, the volume of ethylene glycol accounts for 10% of the volume of the mixed solution A, add formic acid (H 2 CO 2 ), the concentration of formic acid in the solution is 0.07mol / L, continue to stir until the reaction is fully transferred to a high-pressure reactor lined with polytetrafluoroethylene for hydrothermal reaction, the filling degree is 50%, and the hydrothermal reaction is carried out at 185°C 22h, natural cooling to obtain the reaction solution, pouring out the supernatant in the reaction solution to obtain the reactant;

[0069] 3) Th...

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Abstract

The invention discloses a method for preparing hollow spheres and films surrounded by VO2 nanosheets. In the method, a vanadium precursor, ethylene glycol and a reducing agent are added to a mixed solution of ethanol and water at a certain proportion, the mixed solution is transferred to a reaction kettle for hydrothermal reaction. After the reaction, the product is centrifugally washed and driedto obtain a powder sample, and the powder sample undergoes heat treatment in inert atmosphere, so that hollow sphere powder composed of the VO2 nanosheets can be obtained. The films prepared from theVO2 nanosheet hollow spheres present excellent optical properties and sensitivity. Firstly, the VO2 nanosheets are evenly vertically distributed on the surfaces of the hollow spheres, which significantly improves the dispersion of the nanosheets and the porosity of the films, significantly improves the transmittance and modulation capability of the films to visible light, and reduces the hysteresis width of the phase transition. The method is of great value for the application of VO2 in the field of smart glass.

Description

【Technical field】 [0001] The present invention relates to a VO for smart window glass 2 The preparation method of hollow spheres with nanosheets belongs to the field of intelligent materials and is also closely related to the fields of energy and environmental protection. 【Background technique】 [0002] Vanadium dioxide (VO 2 ) crystals can usually be generated from the monoclinic phase (P2 1 / c, low temperature phase) to tetragonal phase (P4 2 / mnm, high-temperature phase) structural transformation, accompanied by the insulator-to-metal phase transition (MIT) process, its resistivity and optical properties change abruptly, especially, its infrared transmittance decreases sharply with the increase of temperature, and this The process is completely reversible. VO 2 The regulation of light before and after the phase transition just meets the requirements of smart windows. In terms of function, smart windows can sense and respond to external stimuli such as light, heat, a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G31/02C03C17/00C08L75/04C08K7/24C08J5/18
CPCC01G31/02C01P2002/72C01P2004/03C01P2004/34C01P2004/62C03C17/009C08J5/18C08J2375/04C08K7/24
Inventor 马飞徐慧妍
Owner XI AN JIAOTONG UNIV
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