Method for preparing monoclinic phase vanadium dioxide and doped nano powder thereof

Abstract

The invention provides a method for preparing nano powder of monoclinic phase vanadium dioxide by using a hydrothermal-high temperature solid phase synthesis method. The method comprises the following steps of: a) reacting a vanadium source with a reducing agent to obtain vanadium dioxide (VO2)(B), VO2(A) or VO2 (paramontroseite) by using a hydrothermal method; b) washing the VO2(B), the VO2(A) or the VO2 (paramontroseite) and then thoroughly drying the VO2(B), the VO2(A) or the VO2 (paramontroseite) to form powder; c) vacuum-packaging the powder of the VO2(B), the VO2(A) or the VO2 (paramontroseite) in an airtight and high-temperature resistant container; and d) annealing the container at the temperature of between 350 and 1,200 DEG C for over 3 hours to obtain the nano powder of the monoclinic phase vanadium dioxide. The method has the characteristics of simple production technology, low production cost, environmental friendliness, higher product yield, higher product purity and easy industrial mass production.

Description

technical field [0001] The invention relates to the technical field of nanomaterial synthesis, in particular to the preparation of VO by hydrothermal-high temperature solid-phase synthesis 2 (M) The method of nanopowder. Background technique [0002] Vanadium (V) oxide compounds are recognized as an important class of thermochromic materials. As the ambient temperature changes, the crystal structure, electric domain structure, and magnetic structure of the vanadium oxide compound will change greatly, resulting in a huge change in its optical properties. Among various vanadyl compounds, the monoclinic phase VO 2 (M) has been receiving extensive attention from both scientific and industrial circles due to the appropriate phase transition temperature, i.e., at 68 °C, the monoclinic phase VO 2 (M) (low temperature insulating phase) will transform into tetragonal rutile phase VO 2 (R) (high temperature metal phase), while the conductivity will occur 10 5 With an order of mag...

AI Technical Summary

Problems solved by technology

[0003] So far, there are three main methods for preparing vanadium dioxide powder with intelligent infrared control properties: one is vapor deposition of VO2 powder under the protection of hydrogen or inert atmosphere. 2 (M) or high-temperature decomposition of suitable precursors, but this method requires harsh conditions and complex equipment. It not only requires expensive equipment and material costs, but it is also difficult to control the valence state of vanadium in it, and it is difficult to obtain a large amount of VO 2 (M) pure phase powder or film

Another method is by using V at high temperature 2 o 5 and V 2 o 3 Quantitative reaction to prepare, but the reaction temperature is too high, generally at 700-800 degrees Celsius, the reaction measurement is difficult to control, and the product is very impure

Another method is to dissolve certain soluble compounds containing V in ethanol, and then burn to prepare VO 2 (M), but the vanadium source required by this method is relatively special, the industrial operation of the combustion method is dangerous, it is easy to generate a large amount of dust, and it needs to consume a large amount of solvent, the cost is very high, and the purity of the product is not particularly high

This makes the monoclinic VO with intelligent infrared isolation regulation 2 (M) The preparation cost of nanopowder is greatly increased, and it is difficult to obtain pure VO 2 (M) Nano powder, not easy to achieve large-scale production

[0004] To sum up, VO 2 (M) The defects in the prior art in the preparation field are that the preparation conditions are harsh, the equipment is complex and expensive, the production cost is high, the product yield and purity are low, the environment is not friendly, and it is not suitable for industrialized large-scale production, etc.

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