Effect of Cadmium Deposition on Electroreduction of Carbon Dioxide by a Copper Electrode

Abstract

Coulometric measurements of electroreduction of CO₂ were conducted with a Cu electrode in the presence of Cd²⁺ in the electrolytes (KHCO₃). Cd²⁺ is deposited durng the reduction (in situ electrodeposition). Fig.2 shows the current efficiencies of the products plotted against the apparent coverage of Cd (S). With an increase in the deposited Cd, hydrocarbon formation decreased, whereas CO and HC00- increased. The CO formation reached a maximum at 8=1. The amounts of Cd on the Cu electrode, composed of adatom and bulk (multilayer) Cd, were measured by the anodic stripping method, and agreed well with those calculated under the assumption of random deposition model under the limiting current conditions. These results indicate that CO is formed on the adatom Cd on the Cu electrode.