Novel SnO₂-based gas sensors promoted with metal oxides for the detection of dichloromethane

A SnO₂-based recoverable thick-film gas sensor was developed in this study for the detection of dichloromethane (DCM) of ppb level at 350 °C. The response of the SnO₂ sensor decreased gradually during multiple cycles of detection and recovery, while the response of the SnO₂-based sensor, promoted simultaneously with Mo and Ni, was maintained during multiple cycles without deactivation. In particular, the Mo3·Ni3(I) sensor, which was prepared by the physical mixing of 3 wt% MoO₃ and Ni/SnO₂ (Ni3(I)) prepared by impregnation of SnO₂ with 3 wt% NiO, showed a very high sensor response of about 50% in the detection of DCM of 0.5 ppm at 350 °C, unlike the SnO₂ sensor which showed a sensor response of about 1.2%. This result was due to the effects of textural property of the pure material and the promoter. The MoO₃ promoter played an important role in the improvement of the recovery ability of sensor, and the NiO promoter played an important role in the enhancement of the response level of the sensor. In addition, the response of the Mo3·Ni3(I) sensor increased almost linearly in the concentration range between 0.1 ppm and 0.5 ppm. Moreover, the sensor showed the response of 30% even at a very low concentration of DCM of 0.1 ppm (100 ppb).