Mathematical model of electrochemical gas sensors with distributed temporal and spatial parameters and its transformation to models of the real YSZ-based sensors

Abstract

The activity in the field of computer-aided optimum design in engineering of electrochemical gas sensors has been increasing steadily over the last decade. A vast range of models exist today, varying in complexity and in the number of assumptions employed. However, the emphasis in a majority of the models has been either on the transport processes or on the electrochemical processes. This manuscript presents a complete mathematical model of electrochemical gas sensors, represented as a system of the partial differential equations of parabolic and hyperbolic types and the algorithm of transfer from the complete model to models of specific sensors. A complete mathematical model shows that the physic–electro–chemical processes occurring in the electrochemical gas sensors can be described more accurately. Presented mathematical model together with the proposed algorithm provides a decision-making tool for better optimal design of the solid electrolyte gas sensors. An example of transfer from a complete model to real model of the yttria-stabilized zirconia (YSZ)-based potentiometric gas sensors has been shown for the YSZ-based oxygen sensor with Pt sensing electrode (SE) and metal–metal oxide (Me–MeO) reference electrode (RE). Verification of the adequacy of the mathematical model to real gas sensor has been evaluated by the Fisher criterion.