Enhanced electroreduction of CO₂ to C₂₊ products on heterostructured Cu/oxide electrodes

Electrochemical reduction of CO2 to value-added multicarbon products has been limited by the inefficiency of the C-C coupling process on Cu. Coupling metal oxides with Cu surfaces offers new freedom to break scaling relationships, thus regulating the product distribution on Cu. Herein, we show that metal oxides with the capability to stabilize the adsorbed CO2*/CO* and decrease the Gibbs free energies of the C-C coupling process can promote the formation of C2+ products on oxide-modified Cu electrodes. As a representative, ZrO2-modified Cu (Cu/ZrO2) electrode shows a high faradic efficiency of 85% for C2+ products. In situ surface-enhanced Raman spectra confirm the enhanced adsorption of CO* on the Cu/ZrO2 electrode, while theoretical calculations reveal the decreased energy barriers of the C-C coupling process at the Cu-ZrO2 interfacial boundaries. This study sheds light on the structure-property relationship of metal-oxide heterostructured electrocatalysts and accelerates the implementation of CO2 electroreduction toward high-value products.