Ionic-liquid based electrochemical ethylene sensor

Abstract

We present an electrochemical ethylene sensor that exploits a thin ionic-liquid (IL) layer as electrolyte. ILs are fluids that completely consist of ions at room temperature and have emerged as extremely promising electrolytes for the following reasons: first, the vapor pressure is practically negligible and therefore even thin films remain stable over time. Second, the solubility of ethylene is higher compared to water leading to an enhanced current. Finally, a thin layer leads to effective ethylene diffusion and therefore enhanced sensor current and response time. We show that ethylene can be detected in a specific potential window and a linear response up to 200 ppm with a detection limit of 25 ppm has been achieved. We foresee that our approach could be extended to other gases and ILs could become widespread in electrochemical gas sensors.