Thick films of In, Bi and Pd metal oxides impregnated in LaCoO 3 perovskite as carbon monoxide sensor

Abstract

Thick films of LaCoO 3 perovskite and metal oxides (In, Bi and Pd) impregnated in LaCoO 3 have been used as sensor materials for sensing temperature and carbon monoxide gas. LaCoO 3 has shown good characteristics of a thermal sensor up to 500 °C. The thermal sensitivity is decreased considerably by the impregnation of metal oxides and it has shown very low with PdO and Bi 2O 3. The sensor response for CO is quite good with a good recovery for the partial pressures from 10 to 40 ppm at 200 and 250 °C. LaCoO 3 has exhibited good response in spite of low sensitivity and better recovery even at 200 °C for 10 ppm partial pressure of CO. Higher partial pressures have given higher sensor responses. Probable mechanisms have been proposed in the light of present investigation and the earlier work.