Galvanic solid electrolyte cells for the measurement of CO 2 concentrations

摘要: The first commercially offered CO2 sensors with galvanic solid electrolyte cells have very different properties. A review of the numerous carbonate described in literature shows that it is easy to obtain CO2-sensitive systems Au, Na2CO3 measuring electrodes. problems obtaining reproducible long-term stability mainly concern reference electrode. Only electrodes composed pure substances, stable under operational conditions, promise desired Reference oxides Mo, W, Sn, Ti, Si and Ge been tested, degrees success. With silica sodium silicate on β-alumina, a sensor results can be used also reducing gas phases without calibration because evaluation signals possible by thermodynamically precalculated equation. volatility presumably caused vapor pressure thin layers creeping substance formation gaseous Na2(OH)2. properties are particularly unfavorable for planar sensors. independent partial O2 H2O, but participation electrode reactions causes cross sensitivities not only carbon-containing gases also, example, NH3 H2. against halogens SO2 irreversible. At sudden changes concentration signal follows within less than few seconds, questions remain concerning observable differences response times differently arranged highly important arrangement aimed at simultaneous measurements real time each breath.