Improvement of long-term stability in SnO2-based gas sensor for monitoring offensive odor

WO₃/SnO₂ ceramics has been suggested as an effective sensing material for monitoring offensive odor or pollutant gases. This work was focused on improving long-term stability, which has been a principal problem generally associated with SnO₂ semiconductor gas sensors. Miniaturized thick film gas sensors were fabricated by screen-printing technique. Two types of sensor materials, W-doped SnO₂ and WO₃-mixed SnO₂, were comparatively investigated with respect to long-term stability and sensitivity to several gases. Small amount of W doping (0.1 mol%) into SnO₂ largely improved the long-term stability. The W (0.1 mol%)-doped SnO₂ gas sensor had higher sensitivity to both acetone and alcohol compared with WO₃ (5 wt.%)-mixed SnO₂ gas sensor. On the contrary, WO₃ (5 wt.%)-mixed SnO₂ gas sensor showed superior sensitivity to cigarette smoke due to larger W content.