(41f) Superoxide-Derived CO2 Reduction at Low over-Potentials and Ultra-Fast: A General Approach in Ionic Liquids

Accomplishing highly selective and efficient electrochemical CO₂ reduction is essential for a sustainable utilization of fossil energy resources. Here, we report ultra-fast CO₂ reduction in ionic liquids (ILs) performed in aerobic environments. CO₂ reduction to CO is observed at a very low over-potentials, namely, >90% faradic efficiency and near 100% carbon selectivity. In the present article, we show that this general approach can be conducted three conventional electrodes (Pt, Au and carbon). The reduction process is initiated by an electrochemical generation of superoxide radicals (O₂^.-) and followed by an efficient CO₂ activation through N-heterocyclic carbene (NHC) CO₂ adducts in IL. The observed experimental results, supported by a first principle computational modeling suggest an ECE mechanism, where O₂^.- superoxide efficiently transforms NHC structures, and activates CO₂ into NHC-CO₂. This work offers a green approach for CO₂ reduction under simple conditions, with potential applications in a broad range of platforms, catalytic systems, and biological processes involving O₂