Two-dimensional copper nanosheets for electrochemical reduction of carbon monoxide to acetate

Upgrading carbon dioxide to high-value multicarbon (C 2+ ) products is one promising avenue for fuel and chemical production. Among all the monometallic catalysts, copper has attracted much attention because of its unique ability to convert CO 2 or CO into C 2+ products with an appreciable selectivity. Although numerous attempts have been made to synthesize Cu materials that expose the desired facets, it still remains a challenge to obtain high-quality nanostructured Cu catalysts for the electroreduction of CO 2 /CO. Here we report a facile synthesis of freestanding triangular-shaped two-dimensional Cu nanosheets that selectively expose the (111) surface. In a 2 M KOH electrolyte, the Cu nanosheets exhibit an acetate Faradaic efficiency of 48% with an acetate partial current density up to 131 mA cm −2 in electrochemical CO reduction. Further analysis suggest that the high acetate selectivity is attributed to the suppression of ethylene and ethanol formation, probably due to the reduction of exposed (100) and (110) surfaces.