3D Heterostructured Copper Electrode for Conversion of Carbon Dioxide to Alcohols at Low Overpotentials.

Active and cost‐effective catalyst materials are required for electrochemical CO2 reduction reactions (CO2RR) which, to date, are proving elusive. Here, the direct electrochemical conversion of CO2 to liquid products with a high overall Faradaic efficiency (FE) by utilizing a unique 3D, heterostructured copper electrode (referred as Cu sandwich) that is obtained via a simple two‐step treatment of commercially available copper foam is reported. The designed catalyst achieves an FE toward liquid products of >50% at an applied potential as low as −0.3 V versus reversible hydrogen electrode. The improved selectivity of the heterostructured Cu sandwich electrode at low overpotentials is attributed to the greater exposure of engineered Cu+/Cu2+ interfaces (present on composite nanowires) and higher oxygen vacancy defects. Moreover, the rationally designed heterostructures prevent the Cu2O species from being reduced during CO2RR enabling the catalyst to demonstrate enhanced CO2RR activity with prolonged stability. A 3D heterostructured copper electrode (Cu sandwich) for CO2 reduction reactions (CO2RR) is fabricated by a simple two‐step treatment of commercially available copper foam. The catalyst demonstrates a high selectivity toward ethanol and methanol production during CO2RR. The improved selectivity of the Cu sandwich can be explained by the presence of Cu+/Cu2+ interfaces and oxygen vacancy defects. [ABSTRACT FROM AUTHOR]