Enhancing C₂–C₃ Production from CO₂ on Copper Electrocatalysts via a Potential-Dependent Mesostructure

The electrochemical conversion of CO2 to hydrocarbons and alcohols for use as a renewable energy storage medium is a promising approach to CO2 utilization and energy sustainability. Herein, we demonstrate that the selectivity of an electrochemically reduced Cu(OH)2 nanowire catalyst toward C2–C3 compounds (ethylene, ethanol, and n-propanol) is systemically modified by surface morphology, which is governed by the electrolysis potential. The total Faradaic efficiency of CO2 reduction to C2–C3 compounds is found to be 38% at a moderate potential of −0.81 V vs RHE, and stable electrocatalytic performance is observed for 40 h of CO2 electrolysis. Electro- and physicochemical analyses indicate that the Cu(OH)2 nanowires are completely reduced to metallic Cu, forming a mesostructured catalyst after a few minutes of electrolysis. The shift in product selectivity is strongly correlated with this change in mesoscale catalyst morphology, offering additional dimensionality and multiple length scales for catalyst design to achieve efficient CO2 reduction to valuable C2–C3 compounds, especially alcohols.