Electrolyte-enabled C–C cross-coupling for directed CO2-to-ethylene conversion

Abstract Electrolyte engineering is critical for steering CO2 electroreduction toward multicarbon products such as ethylene1,2, yet achieving directed conversion and pathway selectivity remains challenging. Here we show an amino-functionalized ionic liquids (AFILs) electrolyte-enabled C-C cross-coupling pathway for directed ethylene synthesis on single-atom catalysts (SACs). AFILs chemically capture CO2 as carbamates, boosting CO production and generating high local CO coverage. The resulting carbamate-derived intermediates (-NHCO*) act as an activated C1 partner, undergoing C-C cross-coupling with CO from SACs and thereby bypassing the need for adjacent metal sites—a key limitation for conventional C-C coupling on SACs. AFILs further stabilize critical intermediates (e.g., *OCCO, *OCCOH) through a hydrogen-bonding network and restructure interfacial water to enhance proton availability. These combined effects lower the reaction barrier while suppressing competing hydrogen evolution and methane formation. By tuning the AFIL structure (Mono‑ vs. Dual‑AFIL), CO2 conversion can be steered selectively toward ethylene, achieving a Faradaic efficiency of 80.5% at a current density of 316.2 mA cm–2 in flow cell. This study introduces an electrolyte-enabled C-C cross-coupling pathway that bypasses the inherent geometric constraints of SACs, opening a new route to direct CO2 electroreduction toward valuable multi-carbon products.