BEHAVIOR OF A NEW ZRO2-MOO3 SENSOR FOR CARBON-MONOXIDE DETECTION

Solid state gas sensors based on semiconducting metal oxides have been widely used for the selective detection and metering of reducing gases such as hydrocarbons, carbon monoxide, hydrogen, etc. in a variety of combustion processes. In this paper, development of a new carbon monoxide gas sensor based on MoO3 is described. It was found that MoO3 thick films could be used as on/off type detectors, whereas those based on thin films and a two-phase mixture of ZrO2-MoO3 could be employed for measuring the concentration of CO gas in the ambient. Addition of small amounts of palladium catalyst seemed to significantly enhance the sensitivity of these sensors in terms of the magnitude of the signal as well as the response time. Based on the experimental results, a possible sensing mechanism of these sensors is also proposed.