Selective Electrochemical Reduction of CO₂ to Ethylene on Nanopores-Modified Copper Electrodes in Aqueous Solution

Electrochemical reduction of carbon dioxide was carried out on copper foil electrodes modified with nanopores on the surface. Such nanopores modified structure was obtained through an alloying-dealloying process. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy confirmed the formation of alloy layer and the final nanoporous morphology of such copper electrodes. When used in electrolysis process, the as-prepared nanopores-modified electrodes can suppress the Faradaic efficiency toward methane to less than 1%, while keeping that of ethylene in a high level of 35% in aqueous 0.1 M KHCO₃ solution under -1.3 V (vs reversible hydrogen electrode), thus revealing a remarkable selectivity toward ethylene production. The high yield of ethylene can be ascribed to the exposed specific crystalline orientations.