Highly selective and stackable electrode design for gaseous CO2 electroreduction to ethylene in a zero-gap configuration

The electrochemical reduction of CO2 to ethylene has the potential to reduce greenhouse gas emissions while producing commodity chemicals for plastics; however, a scalable and feasible system for this remains a challenge. Herein, we report an efficient and stackable electrode design for the electrolysis of CO2 to ethylene. Using KOH-incorporated Cu nanoparticle (Cu-KOH) as the cathode in a zero-gap electrolyzer, Faradaic efficiency of 78.7% for C2 products was achieved at a current density of 281 mA cm–2. Among C2 products, ethylene with a 54.5% FE was dominant product. For mass production, three membrane electrode assemblies (MEAs) were stacked and operated. Operando X-ray absorption spectroscopy under the zero-gap electrolyzer suggested mainly metallic Cu state with some persistent oxide-derived Cu species in Cu-KOH, including Cu2O and Cu(OH)2, which expected a synergistic effect for the conversion of CO2 to C2H4. Our findings provide a new strategy for converting CO2 to C2H4, which is expected to accelerate the commercialization of high-value chemical production through electrochemical CO2 reduction.