Promoting CO Electroreduction to Ethane by Iodide-Derived Copper with the Hydrophobic Surface.

Electrochemical reduction of CO to value-added products provides a feasible pathway for mitigating net carbon emissions and storing renewable energy. However, the low dimerization efficiency of the absorbed CO intermediate (*CO) and the competitive hydrogen evolution reaction hinder the selective electroreduction of CO to ethane (CH) with a high energy density. Here, we designed hydrophobic iodide-derived copper electrodes (I-Cu/Nafion) for reducing CO to CH. The Faradaic efficiency of CH reached 23.37% at -0.7 V vs RHE over the I-Cu/Nafion electrode in an H-type cell, which was about 1.7 times higher than that of the I-Cu electrode. The hydrophobic properties of the I-Cu/Nafion electrodes led to an increase in the local CO concentration and stabilized the Cu species. In situ Raman characterizations and density functional theory calculations indicate that the enhanced performances could be ascribed to the strong *CO adsorption and decreased the formation energy of *COOH and *COCOH intermediates. This study highlights the effect of the hydrophobic surface on Cu-based catalysts in the electroreduction of CO and provides a promising way to adjust the selectivity of C products.