Carbon-coated vanadium dioxide nanoparticles and preparation method thereof

A vanadium dioxide nano, vanadium dioxide technology, applied in the field of carbon-coated vanadium dioxide nanoparticles and its preparation, can solve the problems of reducing material stability, difficult process control, easy to break or break, etc., to improve stability , excellent optical properties, cheap method

Active Publication Date: 2014-02-05
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although the particles are nanoscale in the short axis direction, the long axis direction is far beyond the nanoscale to the micron range, which will bring two problems: ① Due to the strong absorption of vanadium dioxide for visible light, the larger the particle size , the greater the absorption
Calculations show that when VO 2 When the thickness of the material is greater than 100nm, the transmittance of visible light will only be about 20%, which is difficult to meet the basic requirements of smart energy-saving glass (Xu G., Jin P., Tazawa M.Yoshimura K.; Appl.Surf.Sci.244 (2005) pp.449-452), and the long-diameter dimension of the tape-shaped material obtained by this method is on the order of microns; Broken or broken, the fracture is easily oxidized without the protection of the coating material, which reduces the stability of the material
③The dispersion performance of

Method used

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  • Carbon-coated vanadium dioxide nanoparticles and preparation method thereof
  • Carbon-coated vanadium dioxide nanoparticles and preparation method thereof
  • Carbon-coated vanadium dioxide nanoparticles and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0056] Validation of Feasibility of Carbon-coated Vanadium Dioxide Nanopowders Using Optical Theory

[0057]Design spherical or spherical nano vanadium dioxide powder with a size of less than 100nm, with a volume fraction of 2%, and a volume fraction of coated carbon elements of 0 and 5% of the volume fraction of vanadium dioxide, and disperse it in PET resin Among them, a PET film dispersion system with a thickness of 3 microns was formed respectively. Using the effective medium approximation theory (Effective Medium Approximation), select the Maxwell-Garnet theoretical calculation model, and use the optical constants of various related substances to calculate the equivalent optical constants of the system. and near-infrared) range of transmittance spectra, and compared with each other.

[0058] figure 1 for the calculation result. The results show that the effect on the optical properties of the vanadium dioxide nanopowder after coating with a carbon source with a carbon ...

Embodiment 2

[0060] 1) Preparation of rutile phase vanadium dioxide nanopowder: add 5% by weight hydrazine hydrate (N 2 h 4 -H 2 O, Wako Pure Chemical Co., Ltd. special reagent) 640 grams, add 120 grams of vanadium pentoxide powder (V 2 o 5 , Wako Pure Chemicals Co., Ltd.), 1.80 g tungsten oxide (WO 3 , Wako Pure Chemicals Co., Ltd.), and put it into a stainless steel hydrothermal reaction vessel with a magnetic stirring mechanism, and heated at 260 ° C for 24 hours for hydrothermal reaction (the obtained solid was verified to be pure by subsequent XRD analysis, etc. Rutile phase vanadium dioxide nanopowder);

[0061] 2) In-situ carbon coating of rutile-phase vanadium dioxide nano-powder: wait for the temperature of the reaction liquid containing rutile-phase vanadium dioxide nano-powder to drop below 100°C, then add 10 grams of glucose (Sinopharm analytically pure chemical reagents), close the reactor, keep it at 180°C for 8 hours under the condition of full stirring and cool to room...

Embodiment 3

[0068] 1) Prepare rutile phase vanadium dioxide nanopowder: prepare NH 4 VO 3 (N 2 h 4 -H 2 O, Wako Pure Chemical Co., Ltd. special grade reagent) aqueous solution with a mass percentage of 5%, add hydrazine hydrate with a molar mass ratio of 1.2, and add an appropriate amount of WO according to W:V=1.5% atomic percentage 3 , put it into a 100-liter stainless steel magnetic stirring hydrothermal reaction vessel, heat at 270°C for 24 hours for hydrothermal reaction, and after cooling, filter and wash the reaction precipitate, dry at 80°C for 24 hours to obtain rutile phase dioxide Vanadium nano-powder, and put into drying oven for subsequent use;

[0069] 2) Carry out ex-situ carbon coating on the rutile phase vanadium dioxide nanopowder: Weigh 100 grams of the above rutile phase vanadium dioxide nanopowder, together with 4000ml deionized water and 12g sucrose (Sinopharm analytically pure) Put it into a stainless steel magnetic stirring hydrothermal reaction vessel with a ...

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Abstract

The invention relates to carbon-coated vanadium dioxide nanoparticles and a preparation method thereof. The particles consist of rutile-phase nano vanadium dioxide kernels and carbon shells covering the rutile-phase nano vanadium dioxide kernels, wherein the rutile-phase nano vanadium dioxide kernels are approximately square nanoparticles with a length-diameter ratio of being less than 3 and a three-dimensional size of being less than 100 nm; the thickness of the carbon shells are 1-10 nm; the carbon shells account for less than 20 percent by weight of the mass fraction of the particles. The preparation method comprises the following steps: synthesizing the rutile-phase vanadium dioxide nanopowder by using hydrothermal reaction; adding a carbon source into hydrothermal reaction liquid; then performing hydrothermal reaction to perform in-situ carbon coating. The carbon-coated vanadium dioxide nanopowder has superior thermochromic performance, good stability, low cost and high yield and is suitable for large-scale production. The nanopowder can be widely applied to energy-saving coatings, flexible energy-saving films or energy-saving glass of buildings and automobiles.

Description

technical field [0001] The invention belongs to the field of functional nanocomposite materials, in particular to a carbon-coated vanadium dioxide nanoparticle and a preparation method thereof, which can be used for building and automobile energy saving. Background technique [0002] Energy saving and emission reduction has become the top priority at home and abroad. It is estimated that more than 1 / 3 of the total energy consumption of the society is energy consumption of buildings. Since most of the air-conditioning energy in building energy consumption is lost by windows, the development of new energy-saving windows, especially intelligent energy-saving windows that can adjust the transflective characteristics according to seasons and human needs, can achieve maximum comfort while saving energy and environmental protection Living Environment. [0003] Among all kinds of energy-saving windows, the thermochromic smart energy-saving glass developed by using the huge optical...

Claims

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Application Information

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IPC IPC(8): C09C1/00C09C3/06C09K9/00B82Y30/00B82Y40/00
Inventor 不公告发明人
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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