CO2 electroreduction to ethylene via hydroxide-mediated copper catalysis at an abrupt interface.
Cao Thang DinhEdward H SargentMd Golam KibriaAli SeifitokaldaniChristine M GabardoF Pelayo García de ArquerAmirreza KianiJonathan P EdwardsPhil De LunaOleksandr S BushuyevChengqin ZouRafael Quintero-BermudezYuanjie PangDavid SintonEdward H SargentPublished in: Science (New York, N.Y.) (2018)
Carbon dioxide (CO2) electroreduction could provide a useful source of ethylene, but low conversion efficiency, low production rates, and low catalyst stability limit current systems. Here we report that a copper electrocatalyst at an abrupt reaction interface in an alkaline electrolyte reduces CO2 to ethylene with 70% faradaic efficiency at a potential of -0.55 volts versus a reversible hydrogen electrode (RHE). Hydroxide ions on or near the copper surface lower the CO2 reduction and carbon monoxide (CO)-CO coupling activation energy barriers; as a result, onset of ethylene evolution at -0.165 volts versus an RHE in 10 molar potassium hydroxide occurs almost simultaneously with CO production. Operational stability was enhanced via the introduction of a polymer-based gas diffusion layer that sandwiches the reaction interface between separate hydrophobic and conductive supports, providing constant ethylene selectivity for an initial 150 operating hours.