Enhancing CO2 Electroreduction to Ethylene in Acidic Solution by Optimizing Cation Configuration on the Cu Surface

The electroreduction of CO2 to C2H4 offers a promising avenue for advancing carbon neutrality and promoting sustainable chemical manufacturing. In acidic environments, while long-term operational stability and CO2 utilization efficiency are enhanced, the formation of C–C bonds is hindered due to the weak adsorption of *CO intermediates and the competing hydrogen evolution reaction (HER). Theoretical studies suggest that K+ cations with reduced bound water content can strengthen the adsorption of the critical *CO intermediate, and that elevated K+ concentrations on the Cu electrode surface significantly facilitate CO2 electroreduction to C2H4. In this work, a catalyst termed CuTEA was developed by strategically modifying the Nafion ionomer distribution within the catalyst layer. This structural adjustment effectively lowers the bound water associated with K+ cations and concurrently elevates the surface concentration of K+ on the Cu electrode, thereby promoting C–C coupling for C2H4 formation while suppressing HER. Consequently, CuTEA achieves a Faradaic efficiency of 70.2% for C2H4 production, accompanied by a high partial current density of 561.6 mA cm–2 in an acidic electrolyte (pH = 1).