Cesium Tungsten Bronze Ultrafine Powder Preparation

Tungsten trioxide is recognized as an excellent electrochromic material. It has excellent properties in electrochromic, catalytic and gas sensitivity. Tungsten bronze, a composite oxide of tungsten bronze, generally refers to metal oxides with deep metallic luster, and is usually metal conductors or metal semiconductors.

The general formula of tungsten bronze is A_xWO₃. The structure and color of the compounds vary with the type and molar number of cations - A and X values. At present, potassium cesium tungsten bronze and cesium tungsten bronze are widely used to prepare conductive thin films and as insulators in transparent glass thermal insulation coatings because of their low resistance, excellent visible light transmittance and near infrared shielding properties.

At present, there are many methods for preparing cesium tungsten bronze, such as hydrothermal method, solvothermal method, sol-gel method and so on. The above methods have long reaction cycle and low efficiency, which is not conducive to industrial production. Therefore, some scholars have provided a preparation method of cesium tungsten bronze ultrafine powder which saves raw materials and has a short reaction period. The contents include:

(1)Cesium salt and tungsten salt were weighed according to the molar ratio of Cs/W 1: (1.5-2.8). Chelating agent and alcohol reagent were added to react for 3 hours at 170 ℃.

(2)The mixed liquid obtained in step (1) is reacted in a pressure capacitance bomb for 5-8 hours at 260-270 ℃.

(3)Cesium-tungsten powder with complete crystallinity was obtained by washing and centrifuging the reactant obtained in step (2) and vacuum drying at 80 ℃.

The preparation method of cesium tungsten bronze powder mentioned above can effectively simplify its preparation process by controlling the reactants and reduce the production cost of the ultrafine cesium tungsten bronze powder. The prepared cesium-tungsten oxide powder is dark blue ultrafine powder with particle size of 119 nm and powder resistance of (1.2-6.4)*104. It has excellent shielding performance for infrared, especially near infrared.

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