Selective CO Detection by Using Indium Oxide‐Based Semiconductor Gas Sensor

Abstract

From a screening test for the sensing properties of 26 single oxides, an sensor element was found to exhibit rather high sensitivity to both CO and in wet air at 300°C. In order to improve the selectivity to CO vs. , each of 33 metal oxides was added to . As a result, the addition of alkaline metal oxides was found to enhance markedly both sensitivity and selectivity to CO. Particularly, (5 weight percent)‐ element showed the highest CO selectivity. It could detect 500 to 4000 ppm CO in wet air at 300°C satisfactorily.