Solid state electrochemical gas sensor for the quantitative determination of carbon dioxide

A novel solid state electrochemical sensor is presented that enables the quantitative measurement of CO2 gas in atmospheres of CO2 and O-2 in inert gas. The sensor consists of a measuring electrode based on Na2CO3, a series combination of solid ion conductors comprising a ceramic-type component of Na-beta/beta ''-alumina and a salt-type component of Na2SO4, as well as a reference electrode of glass-sealed elemental Na. The sensor yields the thermodynamically expected cell voltage with deviations of less than 1 mV within the temperature range from 300 to 600 degrees C. At intermediate temperatures, it has a response time on the order of a few minutes, and remains functional and drift-free over several weeks of continuous use. Such results have not before been accomplished since the beginning of this research field more than three decades ago. (C) 2018 Elsevier B.V. All rights reserved.