Electrochemical Reduction of CO2 Using Cu-Au Nanoparticles: Effects of Size and Composition

Abstract

The electrochemical reduction of CO2 to light hydrocarbons allows renewable energy storage without increasing net atmospheric CO2. Alloys and nanoscale catalysts have emerged as potential electrocatalysts with high efficiencies and selectivities to valuable products. Here, we describe CuAu alloy nanoclusters with diameters of 2 nm and 5 nm for use as CO2 electroreduction catalysts. The Cu:Au ratio was controlled to yield nanoparticles with a range of alloy compositions ranging from Cu25Au75 to Cu72Au28. The yields and onset potentials were measured and compared to Cu, Au and CuAu bulk foils, where the nanoparticles showed a 50 fold increase in CO yield compared to Au foil, and greater than a 100 mV anodic shift in CO2 reduction onset potentials. As seen in Figure 1, the alloys showed greater improvements in yield as Au content increased. These improvements are attributed to low coordination active sites and to the bimetallic nature of these active sites. Figure 1