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

Vanadia (V
₂
O
₅
) doped tin dioxide (SnO
₂
) 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 V
₂
O
₅
), in presence of 60-65% ambient humidity. 0.50 wt% V
₂
O
₅
loaded SnO
₂
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 SO
₂
at a different V
₂
O
₅
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 V
₂
O
₅
-doped SnO
₂
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.