Effect of P on the electrochemical activity of carbon supported Pt-Ru alloy catalyst for methanol oxidation.

Abstract

In polymer electrolyte membrane fuel cell (PEMFC), platinum is recognized to be the most active metal for methanol oxidation, however there is a strong CO adsorption tendency, which blocks the surface for further methanol adsorption and leads to very low power densities [1, 2]. Pt-Ru and Pt-Sn are the most promising of the binary catalysts for methanol and ethanol oxidation respectively due to the improved CO tolerance. On the other hand, the power densities of Pt-Ru and Pt-Sn anode catalysts for direct alcohol fuel cell is lower than that of the hydrogen PEMFC [3, 4, and 5]. This study aims at improving the performance of the binary catalyst through the addition of phosphorus group following the sodium hypophosphite method [6]. The optimum amount of phosphorus on the Pt-Ru/C, Pt-Sn/C and Pt-Ir/C was investigated by measuring the activity of the catalysts for methanol electrooxidation with cyclic voltammetry and linear chronoamperometry