(182g) Activity and Stability of Gold and Copper Nanoparticles for Electrochemical Carbon Dioxide Reduction

Although the vast majority of fuels and hydrocarbon products are presently derived from petroleum, there is immense interest in the development of alternate routes for synthesizing these products by hydrogenating carbon oxygenates. Electrochemical methods of reducing carbon dioxide could serve as a method of storing electrical energy derived from intermittent sources like solar and wind if efficient catalysts with high hydrocarbon selectivity are developed. Although metals in the form of foils are increasingly well-characterized as electrocatalysts for carbon dioxide reduction, the activity and stability of their nanoscale counterparts remain poorly understood. We present an understanding of the electrochemical conditions and ligands that afford control over the stability of gold and copper nanoparticles for electrochemical carbon dioxide reduction. Random walk simulations reveal the mechanism by which the nanoparticles lose surface area and assemble into dendrites under polarization conditions. In addition, we have found that the gold and copper nanoparticles exhibit selectivities for electrochemical carbon dioxide reduction that are distinctly different from that of their foil counterparts. The changes in hydrocarbon selectivity for the copper nanoparticles are due to an underlying difference in the mechanism by which electrochemical carbon dioxide reduction proceeds on the nanoparticle surface. Our understanding of the activity and stability of copper and gold nanoparticles has enabled us to design a catalytic network for electrochemical carbon dioxide reduction.