Graphite Formation From CO 2 Electroreduction in a Synergistic Ionic Liquid–Liquid Metal System
Nasim Afzali, Maedeh Yahyanezhad Gele, William Varroy, Frédéric‐Georges Fontaine, Jesse GreenerABSTRACT
Electrochemical CO 2 reduction at catalytic liquid metal (LM) surfaces offers a promising route for sustainable carbon conversion, yet suboptimal electrolyte formulations limit its practical implementation. We demonstrate CO 2 reduction at a cerium‐containing liquid metal (LM‐Ce) using, for the first time, an ionic liquid‐based electrolyte that combines high CO 2 solubility, electrochemical stability, and high solution conductivity. Using 1 M 1‐ethyl‐3‐methylimidazolium trifluoromethanesulfonate (EMIM‐TfO) with 2 M H 2 O in N,N‐dimethylformamide (DMF), and under an applied potential of –1.44 V versus standard hydrogen electrode (SHE), the system achieves a high current density while CO 2 reduction to graphite proceeds with an overall faradaic efficiency of 73.2 ± 3.3% and a high degree of graphitization (I G /I D ≈ 5). These results demonstrate that ionic liquids (ILs) function not only as excellent supporting media but may also serve as active and potentially tunable components to improve CO 2 reduction rates at LM‐Ce interfaces.