Stability of Pt-Ru Alloy for Anode Catalyst in PEFC Fuel Cell: A Density Functional Theory Study

Abstract

It is well known that Pt-Ru alloy exhibits a promising catalytic activity for fuel cells. In this work we present density functional theory (DFT) study of the randomly mixed Pt-Ru alloys and discussed its stability based on the relative position of Pt and Ru atoms. The structures are modelled as five layer slabs because the ratio of surface atoms comparable with that for clusters about 3 nm sizes. The top surface fully covered by the Pt atom exhibits highest stability compared with other randomly mixed Pt-Ru alloys. We also discuss here the probability of Pt-Ru bond ratio (MPt-Ru/MPt-Ru+MPt-Pt) in the Pt-Ru alloy decreases with increasing the surface atom ratio (surface atom/Total number of atom), which is compared with available X-ray absorption fine structure data.