Field Trials Testing of Mixed Potential Electrochemical Hydrogen Safety Sensors at Commercial California Hydrogen Filling Stations

Hydrogen safety sensors must meet specific performance requirements, mandated by the U.S. Department of Energy, for hydrogen fueling station monitoring. Here, we describe the long-term performance of two zirconia-based mixed potential electrochemical hydrogen gas sensors, developed specifically with a high sensitivity to hydrogen, low cross-sensitivity, chemical stability across operating temperatures, and fast response time. Over a two-year period, sensors with two different working electrodes-tin-doped indium oxide and strontium doped lanthanum chromite-were deployed at hydrogen filling stations in the Los Angeles area. The sensors exhibit high baseline stability and excellent correlation with logged filling/release events, making these materials good candidates for applications requiring long-life, drift-free baseline operation, in which sensor calibrations and replacements are prohibitive.