CO-CH4 selectivity enhancement by in situ Pd-catalysed microwave SnO2 nanoparticles for gas detectors using active filter

Nanosized tin oxide powders were obtained using microwave procedure for their application on gas sensor technology. This technology allows taking advantage of low cost and high volume mass production for the easy in situ introduction of the palladium catalytic additive. The effects of a controlled high palladium catalysation, reaching active filter properties, are reported showing an enhancement of the selectivity for CO and CH4. In this work, electrical results of the sensor performances are discussed and correlated with their structural parameters and the used technological procedures. Especial emphasis has been devoted to the active filter efficiency deduced from CO consumption measurements. The applicability to the present state of the art in sensor technology of such active-filter catalysed SnO2 is shown by means of its implementation in micromachined substrates operated in pulsed mode. (C) 2001 Elsevier Science B.V. All rights reserved.