Exhaust gas sensors play a critical role in monitoring emissions and regulating engine operation in diesel trucks and cars. Recent emission standards for the United States places more stringent standards on nitrogen oxide emissions from diesel vehicles in order to further limit and reduce air pollutants. Current sensors are not capable of measuring nitrogen oxides at levels that will satisfy 2015 Tier 2, Bin 8 emission standards set by the Environmental Protection Agency. This shortcoming creates a need for diesel exhaust gas sensors with greater sensitivity and accuracy. This project focuses on gas sensors composed of a novel porous ceramic architecture. The research activities in this project are providing a fundamental understanding of how the sensor microstructure affects the electrical properties, kinetic reactions, and electrochemical response of the sensor. This knowledge is important as it has a direct impact on sensor sensitivity, selectivity and accuracy. This project provides research experiences for undergraduate and graduate students through participation in the data collection, analysis, and reporting of research results, which greatly contributes to their university education. The outreach activities range from laboratory research experiences to hands-on afterschool activities with elementary age children.
TECHNICAL DETAILS: New regulatory standards for diesel emissions have established more stringent thresholds for pollutant levels; thereby, creating a need for nitrogen oxide sensors with greater sensitivity, selectivity and accuracy. Current sensors are capable of measuring nitrogen oxide emissions at concentrations down to approximately 10 parts per million, which will not satisfy new standards. Novel porous electrolyte based gas sensors are a promising alternative to conventional diesel exhaust sensors. In this project, the electrical response of sensors with a novel porous zirconia electrolyte and dense perovskite sensing electrodes are being studied over a range of operating conditions. The aim is to acquire fundamental understanding of sensing behavior that is governed by the microstructural properties of the electrolyte and sensing electrode. The data generated is useful for determining kinetic reaction mechanisms, temperature dependence, and operating conditions effecting sensor sensitivity, selectivity and accuracy. The outreach activities range from laboratory research experiences for undergraduate and graduate students, to hands-on afterschool activities with elementary age children.
