Fluorinated Anionic Room Temperature Ionic Liquid-Based CO2 Electrochemical Sensing

Rising CO2 gas levels have been shown to have adverse effects on both the environment and our own wellbeing in sufficiently high concentrations. Current monitoring devices utilize high temperature high power devices that do not allow for the further miniaturization for Internet of Things-based applications. Other solutions suffer from temperature restrictions or cross sensitivity issues. Room temperature ionic liquids (RTILs) are a form of liquid salt that can be tuned for optimal physical and chemical properties for gas sensing applications. In this paper, two fluorinated RTILs, EMIM[BF4] and EMIM[FAP], are subjected to CO2 exposures from 400 to 1000 ppm for understanding their electrochemical response via impedance spectroscopy as well as their ability to be thermally cycled for repeated exposure analysis. Both RTILs show sensitivity and differentiation between CO2 concentrations. However, EMIM[BF4] shows consistent cycling ability toward the development of low power sensors.