HIGHLY SELECTIVE CO SENSOR USING INDIUM OXIDE DOUBLY PROMOTED BY COBALT OXIDE AND GOLD

Among the In2O3-based elements loaded with each of 12 metal oxides [0. 5 weight percent (w/o) each], the Co2O4-added element was outstanding in sensitivity and selectiveness to CO at 250 degrees C. Remarkably th e sensing properties of this element could be increased further by the addition of Au (0.04 w/o). The element thus obtained, Au (0.04 w/o)-C o (0.5 w/o)-In2O3, gave excellent characteristics in sensitivity to CO , selectivity to CO against H-2 and other selected gases, and response s rate at 250 degrees C, giving promise of being applied as a CO senso r for safety control of gas appliances.