New Selective Gas Sensing Device based on Metal Oxide Layer with Suspended Catalyst

A novel kind of metal oxide based gas sensors has been prepared by sputtering to Improve the selectivity towards a specific target gas. A metal oxide thin film has been deposited on an alumina substrate equipped with IDC contacts and heater, at a fixed distance an alumina substrate with a catalyst on one side and a heater on the backside has been positioned. The presence of an independent heater on the catalyst substrate allows the control of its thermal activation. Thus this device modifies the response of the sensitive layer changing the composition of the atmosphere surrounding the metal oxide layer and obtaining a more selective response towards specific gases. The novelty consists in the miniaturization of a system with both sensing element and catalyst in a single case in order to have the catalyst just in front of the sensing layer. The catalyst can be activated affecting the gaseous atmosphere surrounding the sensing layer or non activated.