Density functional investigation of oxygen reduction reaction on Pt₃Pd alloy electrocatalyst

We have investigated the surface structure and electronic properties of Pt segregated Pt3Pd (111) surface within the framework of density-functional theory. Surface adsorption of the oxygen reduction reaction (ORR) mediators including H, O, OH, O-2, OOH, H2O2 and H2O and the related reaction pathways have then been thoroughly examined via determining the corresponding activation energies and reaction heats using climbing-image nudged elastic band (CI-NEB) calculations. It is found that the ORR preferably proceeds via OOH dissociation mechanism on the Pt3Pd (111) surface. Surface corrosion resistivity has also been investigated via evaluating the electrochemical potential shift of the surface Pt atoms. Results verify an enhanced stability against pure Pt (111) in the presence of an oxygen atom and nearly the same stability compared to clean pure Pt (111) surface.