PTFE bound activated carbon - A quasi-reference electrode for ionic liquids

摘要

Commonly used reference electrodes in ionic liquids are either Ag and Pt wires or even newly developed systems of second order mainly based on the Ag/Ag ~+ couple. However, the reference potentials may change while changing the ionic liquid and a universal reference scale has not been found yet. In this publication we report on the performance of activated carbon (AC) as quasi-reference electrode for the use in pure ionic liquid (IL) electrolytes. Ferrocene was used as a redox couple in the ionic liquids [EMIM][BF _4], [EMIM][TFSI], [EMIM][FAP] and [Pyr _(13)][TFSI]. It is shown that all of them exhibit a half-wave potential of 190 mV ± 10 mV indicating that AC may be a good candidate as a quasi-reference in IL.