Sensing of CH4, CO and ethanol with in situ nanoparticle aerosol-fabricated multilayer sensors

A new nanoparticle aerosol method was used to synthesize and directly deposit multilayers of metal oxides on sensor substrates. Flame spray pyrolysis (FSP) was used to fabricate Pd/SnO2 and undoped SnO2 sensors with Pd/Al2O3 filter layers on top. These sensing layers were studied for their gas sensing properties and catalytic conversion for CH4, CO and ethanol. The filter effect of the Pd/Al2O3 layer was compared to single layer sensors and was found to be temperature- and gas-dependent. Sensors with improved behaviour with regard to sensor signal and selectivity have been achieved.