Intercalation of two-dimensional graphene oxide in WO3nanoflowers for NO2sensing

Chemiresistive WO3-GO (WG) nanohybrid sensors were designed by a cost-effective hydrothermal process. The structure, morphology, composition and surface features of the prepared WG nanohybrids were explored by an array of analytical techniques, such as X-ray diffractometry (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDAX), high-resolution transmission electron microscopy (HRTEM) and Brunauer–Emmett–Teller (BET) surface profiling. The gas sensing performance of the WG nanohybrids reveals that the small amount of GO significantly impacts the sensor performance. The enhanced gas sensing performance of the WG nanohybrid sensor with a GO content of 3 weight% exhibits an excellent response to 100 ppm of NO2, attaining 239%, which is nearly fourfold higher than that of pristine WO3(61%) at 150 °C, and shows outstanding selectivity, reproducibility and stability (84.5%). Impedance spectroscopy was employed to understand the interaction between the NO2gas molecules and the WG nanohybrid.