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

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