| Electrochemical impedance spectroscopy (EIS) was conducted on nanoporous gold electrodes prepared from electrochemical dealloying of Ag-Au and Ag-Au-Pt alloys, to investigate the ion transport inside the nanopores. The impedance data was analyzed based on a transmission line model (TLM) to evaluate pore resistance, a sign of effectiveness of mass transport, in various conditions. The pore resistance was inversely proportional to the concentration of electrolyte for HClO4, Na2SO4, and NaClO 4 solutions, but showed slightly enhanced conductivity at very dilute condition for HClO4. This is attributed to the much smaller size of a proton compared to Na+ leading to less ion sieving and hindrance effects. Comparing the impedance of nanoporous electrode with varying pore sizes and depths, it was concluded that shallower porous layer with smaller uniform pores and better connectivity resulted in the lowest pore resistance, and therefore, the most effective ion transport. |
