Electrochemistry of Ethanol Oxidation on Ni-Pt Alloy Electrodes in KOH Solutions

Abstract

The behavior of ethanol oxidation on electro-deposited Ni-Pt electrodes was investigated using cyclic voltammetry and polarization curves in 0.4 M KOH solutions. The ethanol concentration was in the ranges of 0∼0.25 M and 0∼1000 ppm. The rate constants of Ni(OH)₂/NiOOH and the ethanol oxidizing reaction on the Ni-Pt electrodes were calculated and the results were compared with those for Ni electrodes. The anodic current of Ni-Pt electrodes increased with the concentration of ethanol in the forward sweep in both ranges of ethanol concentration. The anodic and cathodic currents on Ni-Pt electrodes increased with scan rate at 0.1 M and 200 ppm concentrations of ethanol. No intersection of anodic current was observed on Ni-Pt electrodes. The kinetic parameters of Ni(OH)₂/NiOOH and ethanol oxidation on Ni-Pt electrodes were determined by comparing the experimental results with kinetic equations. The anodic transfer coefficient of the Ni(OH)₂/NiOOH reaction on Ni-Pt electrodes was larger than that on Ni electrodes while the rate constant, k_c1, of Ni-Pt electrodes was smaller than that of Ni electrodes.