Organic Vapor Sensing Properties of WO3 Platelets Synthesized by Homogeneous Precipitation

Tungsten-trioxide (WO3) platelets powder was synthesized from sodium tungstate by homogeneous precipitation method. The morphology and structure of the WO3 platelets were characterized by field emission scanning electron microcopy and X-ray diffraction. The platelet size is about 1 to 2 mu m in length, and about 350 to 500 nm in thickness. The gas sensitivity of WO3 platelets was studied to methanol, ethanol, acetone, and toluene at different operation temperatures and concentrations. The results showed that the gas sensing increases with temperature within the range of 240-340 degrees C. The sensor had relatively high sensitivities to methanol, ethanol, and acetone at the temperature of 340 degrees C. As a contrast, the sensitivities of the sensor were very low to toluene.