Effects of Cations on Activity and Selectivity in Carbon Dioxide Electroreduction

Efficient heterogeneous electrocatalytic reduction of carbon dioxide to fuels and useful chemicals with renewably-produced electricity would both reduce the atmospheric CO₂ concentration and provide an alternative to fossil fuels. While electrolyte cation effects have been studied extensively with polycrystalline transition metal catalysts, cation effects have not been explored on well-defined, epitaxially-grown electrocatalyst surfaces. We will determine the effects of a variety of cations – including alkali metals, alkali earth metals, and organic bases – on the activity and product selectivity of epitaxially-grown transition metal electrocatalysts for the CO₂ reduction reaction. The samples are tested using an electrochemical flow cell previously designed by our group, and we will use in situ vibrational spectroscopy to detect intermediates on the working electrode surface. In light of our preliminary results, we anticipate that larger metal cations on stepped surfaces will exhibit higher current densities, more selectivity for oxygenated products, and higher C-C coupling activity.