Electrochemical sensor principles for redox–active and acid-base–active gases

Major electrochemical principles for gas sensors are highlighted. In particular, potentiometric, bulk and boundary conductometric sensors are considered with emphasis on the role of transport and rate coefficients with respect to thermodynamics and kinetics of the sensor signal. Most of the sensor principles are designed and tailored for redox–active gases. It is shown how analogous sensor principles can be constructed for pure acid-base interactions allowing an appropriate detection of acid–base–active gases, such as NH3, CO2, H2O.