Rational Design of Amperometric Gas Sensors with Ionic Liquid Electrolytes

Abstract

KWJ Engineering has invested several years of research and development into producing a new, next generation amperometric gas sensing technology for a variety of toxic gases and gases of environmental interest. This approach is based on adaptation of the conventional ideas of amperometric gas sensing into a new, printed package that is very small and ultralow power for modern applications. In the course of this development, we have also been interested in whether room temperature ionic liquids (RTILs) could be used as electrolytes in the amperometric sensor, replacing the conventional aqueous sulfuric acid electrolyte that is usually used. Furthermore, we are interested in whether RTILs can impart advantages in amperometric gas sensing that have not been possible with conventional electrolytes. The availability of diverse RTILs with interesting and sometimes unique chemical properties suggests that selection of the proper RTIL could, for example, significantly improve sensitivity or selectivity to a particular analyte, enabling detection with unprecedented advantages over conventional approaches. This paper will address these issues relative to the design of amperometric gas sensors with RTILs components. We are interested in finding whether an RTIL can impart a distinct advantage over current practice, and furthermore what the critical criteria are for successful selection of RTIL electrolytes in the printed sensor format. We will address these questions as we review recent results from several programs on gas sensor development for toxic and environmental gases.