Figure 18.

Tungsten trioxide for acetone detection: (a) SEM image of WO₃ nanoparticles, (b) inset: SEM image at 200 nm scale, (c) dynamic response to different concentrations of acetone. Reprinted/adapted with permission from Ref. [59]. 2023, Elsevier. Tungsten trioxide as NO₂ sensor: (d) SEM image of WO₃ nanoparticles on porous silicon substrate, inset: zoom on the SEM image at 1 µm scale (e) SEM image of WO₃ nanoparticles on alumina substrate, (f) dynamic response to different gas concentrations of WO₃ on silicon at room temperature, (g) dynamic response to different gas concentrations of WO₃ on alumina at 150 °C. Reprinted/adapted with permission from Ref. [60]. 2014, Elsevier.