Influence of dispersion of NiO on Di(propylene glycol)methyl ether gas sensing properties of SnO₂-based gas sensor

The sensing behaviors of SnO₂ and NiO promoted SnO₂-based thick-film gas sensors were investigated at sub-ppm concentrations of di(propylene glycol)methyl ether (DPGME) in a flow system. A SnO₂ sensor showed low sensor response at these concentrations (ppb levels), whereas the SnO₂-based sensor promoted with NiO showed better sensor response. In this study, NiO promoter was found to play an important role in the enhancement of sensor response. In particular, a SnO₂-based gas sensor was prepared using well-dispersed NiO/SnO₂ as a source material, which was made by impregnating SnO₂ with 3 wt% NiO (referred to as the SnNiI3 sensor), and showed the highest sensor response of 68% at 0.1 ppm DPGME at detection temperature of 350 °C. These results were attributed to the catalytic effect and the dispersion of NiO. Furthermore, the response of SnNiI3 sensor was maintained during multiple detection and recovery cycles without deactivation. We conclude that the SnNiI3 sensor developed during this study provides an excellent means for detecting DPGME at sub-ppm concentrations and that it satisfies sensor response and recovery requirements.