Ethanol and CO electro-oxidation with amorphous alloys as electrodes

In recent years the interest in the use of ethanol as fuel in direct ethanol fuel cells (DEFCs) has increased. Ethanol is less toxic than methanol and the bigger size of the molecule reduces the permeability through the electrolytic membrane. But, the use of this fuel with platinum catalysts leads to the acetaldehyde and acetic acid formation as main reaction products, so the electrical efficiency decreases. Furthermore, platinum shows an important susceptibility to CO poisoning which is formed during the ethanol electro-oxidation. The aim of this work is the study of the electro-catalytic behaviour of ethanol and CO electro-oxidation reaction with amorphous alloys, obtained by mechanical alloying technique. Ni₅₉Nb₄₀Pt _0.6Pd_0.4, Ni₅₉Nb₄₀Pt _0.6Rh_0.4 and Ni₅₉Nb₄₀Pt _0.6Rh_0.2Ru_0.2 compositions were studied. The bi-catalytic alloys show a similar behaviour for the ethanol electro-oxidation. In comparison to these, the current density towards ethanol oxidation decreases with the presence of Ru, although the tri-catalytic electrode shows the best tolerance to CO, with a lower surface coverage compared to other studied.