Analysis of factors affecting response for mixed potential gas sensors

Abstract

Development of mixed potential gas sensors is currently limited by a lack of fundamental understanding towards the relation between theory, materials properties, and practical sensing characteristics. This work derives the expressions of sensor response for typical sensing scenarios, and discusses the affecting factors in conjunction with literature experimental data. Theoretical analyses show that response arises from deviation of the reaction kinetics from the initial one, due to competition of redox reactions or limitation by mass transfer. Among various affecting factors of response, reaction mechanism and ratio of electrochemical activities play a critical role, and the latter could serve as an indicator of response for the electrode material. These findings link practical sensing characteristics to both theory and materials intrinsic properties, and would help guide the design of mixed potential gas sensors.