Electrocatalytic systems generally fall into one of three classes: heterogeneous, homogeneous, and chemically-modified electrode. Examples of the first two currently under investigation will be discussed. Carbon dioxide (CO2) conversion on copper foam electrodes versus planar copper surfaces has been shown to differ both in product distribution and catalytic activity. These studies were conducted in electrolytic solutions of water, in which the concentration of CO2 is ca. 33 mM at room temperature and ca. 75 mM at 0° C. In situ formation of clathrate hydrates is a potential alternative to high pressure for increasing the amount of CO2 available in bulk electrolyte solutions. CO2-reduced products were found to comprise 80% Faradaic efficiency from the clathrate solution at -1.0 V (vs Ag/AgCl). A PNP-type iridium pincer complex developed within the C4 has been shown in prior studies to catalyze the hydrogenation of CO2 to formate under homogeneous thermochemical conditions. Studies support that the same complex is also a modest electrocatalyst for CO2 conversion to formate. A possible electrochemical mechanism is proposed.
Steven Ahn is a fourth-year graduate student in Professor Palmore’s group. He is studying the electrochemical properties of various materials, including porous copper and exfoliated graphene electrodes, molybdenum and iridium metal complexes, and immobilized polymeric films.