The Oxygen Reduction Reaction in Room-Temperature Ionic Liquids

The oxygen reduction reaction (ORR) is one of the most important and widely studied of all electrochemical reactions. In recent years, the ORR has been studied using room-temperature ionic liquids (RTILs), neoteric solvents that consist entirely of ions, in part to reveal insights into electrocatalytic reactions in these media, and also due to increasing interest in the use of RTILs in electrochemical energy storage and conversion. In this article, we provide an overview of the mechanisms of the ORR in RTILs and show that the mechanism of the ORR is very sensitive to the composition of the RTIL; completely different products can be obtained from the ORR by making relatively simple changes to the RTIL composition, or by changing the electrode material. We also describe efforts to modify electrodes with RTILs to change their reactivity for the ORR in conventional electrolytes, with the aim of developing new high-performance electrocatalysts for the ORR.