Gas analysis with arrays of solid state electrochemical sensors: implications to monitor HCs and NO in exhausts

Solid-state electrochemical sensors based on stabilized zirconia may be used for monitoring gas mixtures of several electro-active components. Concepts of multi-component analysis with potentiometric and amperometric sensors are discussed with respect to the simultaneous detection of O2 and HCs or O2 and NOx in exhausts. Recent results demonstrate the possibilities of continuously detecting oxygen, HCs and NOx with arrays of potentiometric or arrays of amperometric electrodes. Amperometric arrays are preferable because of the possibilities connected with fixing oxygen activities and reaction conditions by the applied potentials. The results also demonstrate that system solutions have to be found for each application.