Electrochemical Oxidation of Methanol and Ethanol on Electrodeposited Pd and PdNi-Coated Electrodes

Abstract

Electrodeposited PdNi and Pd samples were tested for methanol and ethanol oxidation reaction (MOR and EOR) in alkaline solution using cyclic voltammetry (CV) and chronoamperometric (CA) measurements. Among the CVs for the MOR, all alloy samples showed higher current densities than pure Pd. Also the peak current densities for MOR of PdNi coatings are 5 to 8 times higher than that obtained on Pd coating depending on composition. Based on the ratio of the forward peak current to the backward peak current the tolerance of the catalysts to accumulation of carbonaceous species is determined. Besides this ratio increased with extending the anodic potential limit. The most tolerant catalyst is found to be Pd_0.74Ni_0.28 in methanol oxidation. Comparative study of methanol and ethanol electrooxidation in the alkaline media reveals that Pd_0.74Ni_0.26 alloy has a higher catalytic activity, as well as a better tolerance to accumulation of carbonaceous species.