LAUSR

Abstract We report on the first observation of the production of C 2 /C 3 species from the electrochemical reduction of CO 2 at the surfaces of copper-modified boron-doped diamond (Cu-BDD) electrodes in aqueous media at room temperature and ambient pressure. The product distribution is dependent on the amount of deposited Cu and the applied potential. At low potential, −1.0 V ( vs. Ag/AgCl), ethanol was observed as the main product with acetaldehyde and acetone as side products. The highest faradaic efficiencies obtained for ethanol, acetaldehyde and acetone were 42.4%, 13.7% and 7%, respectively. The Cu particles on the surfaces of the BDD electrodes remained stable, showing insignificant differences after the CO 2 electroreduction process under these particular conditions. The efficiency dropped with increasing Cu deposition time and at high reduction potentials. Moreover, we present comparisons with a Cu plate and Cu-modified glassy carbon as working electrodes under the same conditions, which explains the specific behavior of the CO 2 reduction process on the Cu-BDD electrode.