CO2 Electrocatalytic Reduction at Gold and Copper Electrodes: Role of Particle Size and Surface Chemistry
From the literature, results of CO2 electroreduction on bulk Cu, Au and Au-Cu alloys are known (1-3) as are the size effects of Cu and Au nanoparticles (4, 5), but the effect of chemical surface modification is still unknown, as is the size effect of gold/copper alloy nanoparticles.
In this work we demonstrate the effect of chemical surface modification and the size effect of Au-Cu alloy nanoparticles with the aim of combining the two effects to improve CO conversion and hydrogenation. The effect of surface chemistry is studied using planar electrodes modified by organic compounds. Copper and gold foils are exposed to strongly adsorbed ligands such as alkylthiols and glutathione (GSH) and subsequently used as electrocatalysts. As shown in Figure 1, where copper foil was modified with GSH, the adsorbed ligands strongly affect the product yields and selectivity. At the optimal CO yield potential, the yield of CO on the GSH-modified copper was 2.4 times that of blank bulk copper. Although the yield of CH4 has been decreased by a factor of 0.5 in exchange, the overall yield of gas product has been increased by a factor of 2 on the surface engineered electrode.
The size effect of Au-Cu nanoparticles is investigated using nanoparticles synthesized via the Brust-Schiffrin method immobilized in various binder inks as electrocatalysts for CO2reduction. Ultimately, we consider the potential to break scaling relationships associated with conventional metal electrodes through the use of size control, alloys and ligands.
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