Rotating ring-disk electrode study on the cathodic oxygen reduction at Nafion®-coated gold electrodes

Abstract

Abstract The influence of Nafion® films on the kinetics of cathodic oxygen reduction was investigated using Nafion®-coated gold electrodes. A rotating ring-disk electrode (RRDE) technique was used to determine kinetic parameters for O2 reduction and to detect intermediate H2O2 formation. Kinetic parameters such as the kinetic current, Tafel slope, potential dependence of the ratio of the direct 4-electron reduction to the series 2-electron reduction were determined and compared with those obtained at bare Au in 0.5 M H2SO4. The kinetic data showed no clear evidence of the enhancement effects of Nafion®-coating on the cathodic O2 reduction at Au. This suggested that the Au surface has less affinity for the hydrophobic region of Nafion®, in which a high O2 solubility is expected.