The catalytic effect of Mo on the properties of SnO2-based thin film sensors

In this paper we report the sensing characteristics of pure and Mo-doped tin oxide thin films (a maximum amount of 25% at. Mo was used), deposited with the sol-gel technique. The structural analysis showed that Mo atoms are homogeneously distributed within the SnO2 lattice in form of Mo (VI) and Mo (V) sites. DC electrical measurements on these sensors show that the Mo doping improves the detection of alcohols (ethanol and methanol) and make worse the response to CO and NO2. These results are explained by the hypothesis that Mo atoms promotes the dehydration reactions instead of dehydrogenation ones, which are typical of pure SnO2.