Electrochemical CO2 reduction driven by renewable electricity is one of the promising strategies to store sustainable energy as fuels. However, the selectivity of value-added multi-carbon products remains poor for further application of this process. Here, we regulate CO adsorption by forming a Nafion layer on the copper (Cu) electrode that is repulsive to OH−, contributing to enhanced selectivity of CO2 reduction to C2+ products with the suppression of C1 products. The operando Raman spectroscopy indicates that the local OH− would adsorb on part of active sites and decrease the adsorption of CO. Therefore, the electrode with repulsive to OH− can adjust the concentration of OH−, leading to the increased adsorption of CO and enhanced C–C coupling. This work shows that electrode design could be an effective strategy for improving the selectivity of CO2 reduction to multi-carbon products.