Cesium Tungsten Bronze Hydrothermal Synthesis

Cesium tungsten bronze (CsxWO3) is a kind of non-stoichiometric functional compound, with a specific structure of oxygen octahedral, having a low resistivity and low temperature superconducting properties. In recent years, it's also found that CsxWO3 films have good near-infrared shielding performance, which is expected to replace the existing ITO conductive glass as a window material or that can be used as a good near-infrared heat insulation materials, having very attractive prospects in the automotive and construction sector. Currently the synthesis method of CsxWO3 is mostly confined to high-temperature thermal reduction, such as the vapor chemical transport method by Hussain, the hydrogen reduction method by Takeda, the solid-phase method by Leonova, such methods have shortcomings the high test equipment requirements and experimental process difficult to control.

As a simple and practical synthesis method, hydrothermal synthesis has been widely used in the tungsten bronze synthesis of Li, Na, K, etc., but the hydrothermal synthesis method for the synthesis of CsxWO3 has been reported in recent years. CsOH and WCl6 as raw materials, use solvothermal synthesis at a low temperature (200 ℃) for the first time, CsxWO3 powder is synthesized in ethanol solution. The research shows CsxWO3 films have good near-infrared shielding properties. CsOH and WCl6 are easily hydrolyzed and volatile, which is harmful to humans and the environment, therefore a more moderate material is used to synthesized CsxWO3 powder, which is necessary for achieving CsxWO3 powder scale production and practical application. Thus, cesium carbonate and sodium tungstate were used as raw materials in an experiment, citric acid as the reaction solvent, prepared CsxWO3 powder by hydrothermal synthesis, which studied the effects of the hydrothermal reaction time, the content of citric acid and ethanol on the synthesized CsxWO3 powder's light absorption capacity, and to further explore the effect of UV irradiation on the near-infrared shielding performance of CsxWO3 film, analyzed the mechanism of absorption spectra and transmission spectra.