Validation of High Throughput Electrochemical Gas Sensing Screening System

The development of solid-state, high temperature gas sensors for detecting combustion byproducts is essential to improve energy efficiency, reduce toxic emissions, and meet new environmental regulations. However, gas sensors for such applications must be capable of exhibiting high sensitivity and selectivity to analyte gases at high temperatures. At those temperatures, materials tend to inter-diffuse between layers and react with each other or the environment, negatively impacting sensor performance. Most current state-of-the-art gas sensors involve the doping of a base oxide with aliovalent or isovalent metals, here subatomic differences in composition substantially affect the ultimate sensor figure of merit. Optimizing sensor performance by testing the effect of changes to the dopant concentrations via one-sample-at-a-time methodology is a time consuming effort. The application of the high-throughput methodologies to probe the composition-microstructure-device performance phase space can expedite the search for materials with enhanced figure of merit. This project focuses on developing and validating new high-throughput sensor synthesis and characterization techniques. The approach uses a high-temperature electrochemical screening cell capable of simultaneously quantifying the sensitivity and selectivity of up to 30 individual gas sensing materials arranged in a planar geometry. To validate the electrochemical system, a uniform standard sample was synthesized and tested under NO gas flow at 600 °C.  Preliminary electrochemical tests were performed on the standard sample while alternating the dosing of N₂ and different concentrations of diluted NO. The potential, measured using a multimeter, changed reproducibly during NO dosing, providing initial validation of the use of a planar sensor design for screening.