Switching of selectivity from sulfur dioxide to butane: The role of V2O5 concentration in nanostructured SnO2 sensors

Vanadia (V₂O₅) doped tin dioxide (SnO₂) nanocrystallites were synthesized by sonication assisted simultaneous precipitation method, keeping in view their application for LPG (n-butane) gas sensor. The best sensing conditions were determined by studying the sensors under different operating temperatures with different vanadium loading (in the form of V₂O₅), in presence of 60-65% ambient humidity. 0.50 wt% V₂O₅ loaded SnO₂ exhibits the best sensitivity against butane at 4500C operating temperature, without using any expensive nobel metal catalyst. The same material exhibited a switching in selective sensing of SO₂ at a different V₂O₅ concentration (0.15 wt%), operated at lower temperature (3500C). The nanocrystalline powders were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and current-voltage (I/V) measurement studies. The morphology of V₂O₅-doped SnO₂ nanocrystalline powder is elongated spherical in shape and the distribution of particle size is uniform, having the range of 70-90 nm, as confirmed by SEM and Brunauer-Emmett-Teller (BET) observations.