Surface design of alloy protection against CO-poisoning from first principles

Pt-based alloy catalysts are of significant importance in fuel cells due to enhanced electrode reactivity and selectivity. Designing alloy surfaces suitable for catalyst via first-principles predictions has long played a central role in identifying promising candidates. We propose surface design for polymer electrolyte fuel cell (PEFC) based on the use of thermodynamically stable alloy surfaces. Using first-principles calculation, we have explored stable Pt alloy surfaces that possess superior catalytic properties for CO-despoisoning in hydrogen-related reactions of fuel cells. The stable Pt(25)M(75) (M = Rh, Cu) alloy surfaces both exhibited weaker CO and stronger H binding compared to the pure Pt surface, which yielded a significant increase in H coverage by around one order. These modifications of molecular adsorption are attributed to the deeper band centre of surface d electrons. Understanding the adsorption properties of the stable atomic structure at surfaces will help us to design suitable alloy surfaces with high-catalytic activity and prolonged actuation in fuel cells.