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 0.4M KOH solutions. The ethanol concentration was in the ranges of 0-0.25M and 0-1000ppm. 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 cl, of Ni-Pt electrodes was smaller than that of Ni electrodes. © 2009 The Japan Institute of Metals.