Structuring Cu Membrane Electrode for Maximizing Ethylene Yield from CO2 Electroreduction

Abstract Electrocatalytic ethylene (C 2 H 4 ) evolution from CO 2 reduction is an intriguing route to mitigate both the energy and environmental crises; however, to acquire industrially relevant high productivity and selectivity at low energy cost remains to be challenging. Membrane assembly electrode has shown great prospect and tailoring its architecture for maximizing C 2 H 4 yield at minimum voltage with long‐term stability becomes critical. Here a freestanding Cu membrane cathode is designed and constructed by electrochemically depositing mesoporous Cu film on Cu foam to simultaneously manage CO 2 , electron, water, and product transport, which shows an extraordinary C 2 H 4 Faradaic efficiency of 85.6% with a full cell power conversion efficiency of 33% at a current density of 368 mA cm −2 , heading the techno‐economic viability for electrocatalytic C 2 H 4 production.