Rare earth metal-oxide-based CO2 gas sensor

A CO2 gas sensor composed of rare earth metal oxide added to alkaline metal carbonate and alkaline earth metal compounds has been newly developed. In this study, the effect of various additive to the rare earth metal oxide on the gas sensitivity is examined. It is found that Na2CO3 and CaO additives are effective in increasing the gas sensitivity and the Na2CO3—CaO—BaCO3—Y2O3 system has the maximum gas sensitivity among the samples examined. The newly developed sensor has many excellent characteristics in terms of speed of response, gas selectivity and ambient humidity independence. Further, from XRD analyses, it is observed that the CO2 gas sensitivity of the sensor is closely related to the crystal structure of the gas-sensing materials.