Abstract
Planar resistive type SO2 sensors based on V2O5/WO3/TiO2 (VWT) have been reported to respond well to SO2 but with large cross-effects of NO and NH3. In this study, we added a porous Pt/alumina cover layer on a VWT film in order to decrease the cross sensitivities. The sensor response to SO2 is hardly affected by the Pt/alumina layer in the case of VWT sensor with 3.0 wt % V2O5 with Au electrodes, while the Pt/alumina layer affects the response of other VWT sensors. The VWT sensor (3.0 wt % V2O5) with Au electrodes with the porous Pt/alumina cover layer shows much smaller responses to CO, H2, H2O, NH3, and NO compared with the sensor without Pt/alumina cover layer. The porous Pt/alumina cover layer has a potential to improve the selectivity of the VWT sensor.
