Vapour sensing properties of a cadmium oxide–antimony oxide system ceramic, Cd2Sb2O6.8

Abstract

The vapour sensing properties of a tetragonal pseudo-pyrochlore, Cd₂Sb₂O_6.8, are reported Cd₂Sb₂O_6.8, prepared by a high-temperature solid-state synthesis, is an n-type semiconductor. Thick-film sensors incorporating Cd₂Sb₂O_6.8 as the active material were fabricated utilising screen printing technology. Sensors heated to 250–500 °C were exposed to low concentrations of vapours associated with food spoilage (ethanol, ethyl acetate, limonene, pinene and toluene). The sensors were monitored through the current across the electrodes as a result of a small applied voltage. Tin dioxide sensors were also fabricated to act as a comparison. The results highlight considerable selectivity differences between the Cd₂Sb₂O_6.8 and SnO₂ sensors, particularly with regard to humidity responses where the lack of response for Cd₂Sb₂O_6.8 is crucial for an operational gas sensor. An unusual feature is ‘chiral’ responses exhibited by Cd₂Sb₂O_6.8 to limonene (orange oil) and pinene (pine oil) which may have practical applications in the stereochemistry field.