Thermoelectric carbon monoxide sensor using Co-Ce catalyst

A thermoelectric (TE) carbon monoxide sensor has been examined, which is composed of a Co-Ce oxide catalyst layer and a TE layer. The catalyst plays an important role in this sensor. The Co-Ce oxide catalysts were prepared by a co-precipitation and tablet compression method. Several factors including the atomic ratio of Co/Ce, pH value, tablet compression pressure, calcination temperature, and operating temperature were investigated. EDS analysis was utilized to determine the final composition between Co and Ce. Methods of BET, XRD, SEM and H2-TPR were used to characterize the catalysts. When the Co10.0Ce catalyst showed a high temperature difference output (44 °C) at an operating temperature of 92 °C, the TE sensor possessed good sensing property to 3 vol% CO with a high output voltage signal (42 mV). The response and recovery time of the TE sensor was 72 s and 68 s, respectively. Furthermore, high selectivity of the sensor was also obtained in the operating temperature from 90 °C to 125 °C.