Selective CO2 Electroreduction to Ethylene and Multicarbon Alcohols via Electrolyte‐Driven Nanostructuring

Abstract Production of multicarbon products (C 2+ ) from CO 2 electroreduction reaction (CO 2 RR) is highly desirable for storing renewable energy and reducing carbon emission. The electrochemical synthesis of CO 2 RR catalysts that are highly selective for C 2+ products via electrolyte‐driven nanostructuring is presented. Nanostructured Cu catalysts synthesized in the presence of specific anions selectively convert CO 2 into ethylene and multicarbon alcohols in aqueous 0.1 m KHCO 3 solution, with the iodine‐modified catalyst displaying the highest Faradaic efficiency of 80 % and a partial geometric current density of ca. 31.2 mA cm −2 for C 2+ products at −0.9 V vs. RHE. Operando X‐ray absorption spectroscopy and quasi in situ X‐ray photoelectron spectroscopy measurements revealed that the high C 2+ selectivity of these nanostructured Cu catalysts can be attributed to the highly roughened surface morphology induced by the synthesis, presence of subsurface oxygen and Cu + species, and the adsorbed halides.