Gas sensing characteristics of WO₃ nanoplates prepared by acidification method

WO₃·H₂O nanoplates were prepared by the acidification of Na₂WO₄· 2H₂O and converted into monoclinic WO₃ nanoplates by heat treatment. The sizes, morphologies and preferred orientation of the WO₃ nanoplates could be controlled by manipulating the acidity of the solution used for the acidification reaction. All of the WO₃ nanoplates showed the selective detection of NO₂ in the presence of other reducing gases, such as C₂H₅OH, CH₃COCH₃, CO, C ₃H₈, and H₂. The gas response, selectivity, and response speed were optimized by varying the morphology of the sensing materials and operation temperature. The WO₃ nanoplates with a mean edge size of 192 nm showed the most rapid gas response along with a high response and selectivity to NO₂ when operated at 300 °C.