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

The electroreduction of CO 2 to C 2 H 4 offers a promising avenue for advancing carbon neutrality and promoting sustainable chemical manufacturing. In acidic environments, while long-term operational stability and CO 2 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 CO 2 electroreduction to C 2 H 4 . In this work, a catalyst termed Cu TEA 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 C 2 H 4 formation while suppressing HER. Consequently, Cu TEA achieves a Faradaic efficiency of 70.2% for C 2 H 4 production, accompanied by a high partial current density of 561.6 mA cm –2 in an acidic electrolyte (pH = 1).