Synthesis and characterization of tungsten trioxide powders prepared from tungstic acids

摘要

WO3 powders were prepared by the thermal decomposition of tungstic acids (WO3 nH2O, n ¼ 1/3, 1, 2). Thetungstic acids were synthesized from WO42 aqueous solutions under a variety of conditions of pH, temperatureand W(VI) concentrations. The thermal decomposition of the tungstic acids into WO3 was analysed by TG andDSC methods. Nano-sized WO3 powders with different morphological characteristics were obtained by thermaltreatment of the tungstic acids at 500 8C in air atmosphere. The morphologies of WO3 powders werecharacterised by scanning electron microscopy and infrared absorption spectroscopy. Patterns of infrared spectrawere related with distinct powder morphologies.