A novel tin oxide-based recoverable thick film SO2 gas sensor promoted with magnesium and vanadium oxides

An SnO2-based thick film gas sensor was developed to detect sulfur dioxide (SO2) gas at the ppm level. The SnO2-based sensors were prepared by mixing tin oxide with various promoters such as V2O5, MoO3, Sb2O3, Al2O3, CeO2, and MgO. Their sensor responses and recovery behaviors were investigated in a flow system. It was found that the SnO2-based gas sensor promoted by simultaneous mixing of both 5 wt% MgO and 2 wt% V2O5, showed not only a 44% sensor response for the detection of SO2 at the 1 ppm level, but also good repeatability by means of thermal treatment in air. In particular, this sensor showed a response of approximately 20% even at the level of 0.1 ppm (100 ppb). The sensor recovery properties, as well as the sensor response, could be enhanced by the simultaneous addition of both MgO and V2O5 promoters as compared with the SnO2 sensor. These results are due to the promoting effects of MgO and V2O5 on response and recovery properties of the SnO2-based sensor, respectively.