Reduction of Oxygen at Polyaniline Electrodes Modified with Platinum and Iron

Abstract

In our previous paper, we have shown that platinum dispersed polyaniline (PAn) electrodes exhibit high catalytic activity for the electrochemical oxidation of methanol. In this paper, the catalytic activity of Pt dispersed PAn electrode towards the reduction of oxygen was studied to develop highly performed direct methanol fuel cell. Voltammetric measurements showed that the oxygen reduction currents of Pt modified PAn (Pt/PAn) electrodes are apparently higher (about twice under optimum conditions) than those of Pt dispersed carbon electrodes. The effect of pre-deposition of iron onto PAn surface was studied to reduce the amount of expensive platinum. When total amount of Pt and Fe was kept at constant, the catalytic activity of Pt (25%)/Fe (75%)/PAn electrode was slightly higher than that of Pt (100%)/PAn electrode. This indicates that about 80% of Pt can be replaced by inexpensive iron.