The role of transition metals in the catalytic activity of Pt alloys: quantification of strain and ligand effects.

The oxygen reduction reaction (ORR) activity as a function of thickness of the Pt shell on Pt-Ni alloy nanoparticles was established. We demonstrated that the effects of transition metals could only extend to a very thin Pt shell, which was 0.9-1.0 nm for Pt3Ni.