Doping Metal Elements of WO₃ for Enhancement of NO₂-Sensing Performance at Room Temperature

WO 3 nanoparticles doped with Sb, Cd, and Ce were synthesized by a chemical method to enhance the sensing performance of WO 3 for NO 2 at room temperature. The doping with Sb element can significantly enhance the NO 2 -sensing properties of WO 3 . Upon exposure to 10 ppm of NO 2, particularly the 2 wt % Sb-doped WO 3 sample exhibits a 6.8-times higher response and an improved selectivity at room temperature compared with those of undoped WO 3 . The enhanced NO 2 -sensing mechanism of WO 3 by doping is discussed in detail, which is mainly ascribed to the increase of oxygen vacancies in the doped WO 3 samples as confirmed by Raman, photoluminescence, and X-ray photoelectron spectroscopy spectra. In addition, the narrower band gap may also be responsible for the enhancement of response as observed from the corresponding ultraviolet–visible spectra.