Catalytic Reduction of CO[sub 2] to Ethylene by Electrolysis at a Three-Phase Interface

Carbon dioxide has been selectively reduced to ethylene with a CuCl-confined Cu-mesh electrode. In this system, the reduction is performed at the three-phase (gas/liquid/solid) interface, and is supplied to the electrode surface from the gas phase, permitting us to maintain a high concentration of irrespective of the solubility of in the solution. A maximum faradaic efficiency (69.5%) for was obtained at −1.8 V vs. Ag/AgCl, and the selectivity estimated on the basis of carbon content was 74%. The selective reduction of to ethylene is attributed to the ability of CuCl to reversibly combine with CO and First, is electrochemically reduced to CO(g) at the three-phase interface, and then CO is adsorbed on CuCl with its π bond perpendicular to the surface. Further electrochemical reduction of CO leads to the generation of and the coupling of methylene radicals to The ethylene thus formed may be stabilized by being adsorbed on CuCl with its π bond parallel to the surface.