Effect of Electrode Geometry on Selectivity and Activity in CO2 Electroreduction

We investigated the effect of the electrode geometry on the product selectivity and catalytic activity in CO2 electroreduction (CO2ELR) for equal-surface-area Cu and Ag electrodes. Three different geometries (wire coil, foil coil, and flag) with relatively smooth surfaces were chosen for this study. The electrode geometry impacts the current density distribution on the electrode and the different current densities create an electric field distribution on the electrode surface. The geometry that causes the higher current density distribution (wire coil) showed higher total current density and lower charge transfer resistance, in comparison with the flag-shaped electrodes for both Cu and Ag. The results showed that the current density distribution changes due to the geometry influence the product selectivity as well. Cu coil electrodes showed higher faradaic efficiency (FE) for C-2 products, in comparison to the Cu flag. Ag coil showed higher FE% for CO, compared to the Ag flag.