Abstract
We report an electrochemical reactor that converts 3.0 M KHCO3 into methane at the cathode while oxidizing water at the anode. The reactor achieved a methane yield of 34% at a partial current density of 120 mA cm–2 by using a reactive carbon solution feedstock rather than gaseous CO2. H+ delivered by a bipolar membrane forms CO2 at the cathode, which is subsequently reduced into methane. A cationic surfactant suppresses hydrogen evolution and increases methane formation, providing design principles for electrochemical methane synthesis from reactive carbon solutions.