Selective detection of ammonia and benzene via zeolite films deposited on SnO/sub 2//Pt-SnO/sub 2/ thick film gas sensors

Thick film pure and Pt-doped SnO ₂ gas sensors covered with zeolite films (zeolite A and silicalite) were fabricated and used for gas sensing of different species (ethanol, ammonia, benzene, carbon monoxide and humidity). The results obtained with these sensors were compared with the response of a reference sensor without a zeolite layer. The results clearly show that a suitable zeolite layer strongly reduces, and in some cases suppresses, the response of the sensor to some of the studied gases, thus increasing sensor selectivity. These results clearly state the potential of zeolite-based sensors to achieve a higher selectivity in gas sensing applications.