Impact of Palladium Decoration on the Performance of Co-SmFeO₃ Based Gas Sensor

Abstract

The enhanced ammonia gas sensing properties of palladium decorated Co-SFO are demonstrated here. Pristine SmFeO3 thick films fabricated by screen printing technique were surface modified with Co by dipping method (dipping time 3 min) and identified as Co-SFO thick films. They showed maximum sensitivity to 50 ppm ammonia at 200 °C. In order to further increase its sensitivity, Co-SFO thick film was dipped into Palladium nitrate solution for 1 min, 2 min and 3 min. Surface morphology of as-prepared thick films was studied by FE-SEM. Formation of PdO phase and its uniform distribution over Co-SFO surface was confirmed from EDAX spectra. Gas sensing results revel that the sensitivity of Pd decorated Co-SFO thick films towards 50 ppm ammonia was increased. Moreover, decrease in operating temperature was also observed. Pd decorated Co-SFO thick film with dipping time 3 min has maximum sensitivity at lower operating temperature. The improved sensitivity at low temperature was attributed to the sensitization of palladium which was discussed in details. Keywords: Co-SFO, Chemical sensitization, Noble metal, Gas Response, Reducing gas.