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

WO₃ nanoparticles doped with Sb, Cd, and Ce were synthesized by a chemical method to enhance the sensing performance of WO₃ for NO₂ at room temperature. The doping with Sb element can significantly enhance the NO₂-sensing properties of WO₃. Upon exposure to 10 ppm of NO₂, particularly the 2 wt % Sb-doped WO₃ sample exhibits a 6.8-times higher response and an improved selectivity at room temperature compared with those of undoped WO₃. The enhanced NO₂-sensing mechanism of WO₃ by doping is discussed in detail, which is mainly ascribed to the increase of oxygen vacancies in the doped WO₃ 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