Au-doped WO3-based sensor for NO2 detection at low operating temperature

Pure and Au-doped WO3 powders for NO2 gas detection were prepared by a colloidal chemical method, and characterized via X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The NO2 sensing properties of the sensors based on pure and Au-doped WO3 powders were investigated by HW-30A gas sensing measurement. The results showed that the gas sensing properties of the doped WO3 sensors were superior to those of the undoped one. Especially, the 1.0 wt% Au-doped WO3 sensor possessed larger response, better selectivity, faster response/recovery and better longer term stability to NO2 than the others at relatively low operating temperature (150 °C).