Electrochemical reduction of CO ₂ to value added products

To investigate how the chemistry of an electrolyte impacts the surface behaviour and electro catalytic performance of copper electrodes during the electrochemical reduction of carbon dioxide (CO 2 ), experiments were performed using varying concentrations of potassium hydrogen carbonate (KHCO 3 ) in near neutral solutions, at open circuit and through the use of several types of electrochemical techniques; specifically, linear sweep voltammetry, chronoamperometry, and measurements of open circuit potential. The results demonstrate that the open circuit potential of copper immersed in these solutions is shifted upward when exposed to CO 2 as compared to when exposed to nitrogen, while increased cathodic current density was observed. These results confirm that the presence of CO 2 causes the formation of a conditioned electrode/solution interface on copper. Increased KHCO 3 solution concentrations result in higher cathodic current densities and better stability of the cathodic process, indicating that the ability of the electrolyte to act as a buffer, or to increase the strength of the ions within it, are important factors controlling the rate and efficiency of this reaction.