A Three Electrode Mixed Potential Sensor for Gas Detection and Discrimination

A major goal for sensors in the automotive exhaust emissions control and monitoring field is the development of a single sensor to monitor NO x , NH 3 , CO, and hydrocarbons. Mixed potential electrochemical sensors can be readily tuned to be selective towards different gas mixtures by changing the composition of their electrode or applying a voltage or current bias. We have developed a three-electrode sensor comprised of Pt, La 0.8 Sr 0.2 CrO 3 (LSCO), and Au 0.5 Pd 0.5 electrodes with a porous (Yttria-stabilized Zirconia) YSZ electrolyte which can detect single and binary gas mixtures of NO, C 3 H 8 , and CO. The sensitivity of the electrode pairs were investigated and it was found that AuPd+Pt was most sensitive to CO while LSCO+Pt is best at detecting C 3 H 8 . From the sensor responses, we have trained artificial neural networks to use the voltage responses to recover the gas concentrations and classify the gas mixtures.