"Get in Touch and Keep in Contact": Interface Effect on the Oxygen Reduction Reaction (ORR) Activity for Supported PtNi Nanoparticles

Elucidating the interplay between shape, chemical composition, and catalytic activity is an essential task in the rational nanocatalyst design process. We investigated the activity of MgO-supported PtNi nanoalloys of ∼1.5 nm toward the oxygen reduction reaction using first-principles simulations. Cuboctahedral-shaped particles result to be more active than truncated octahedra of similar sizes, and alloying produces a quantitative improvement in the catalytic activity independent of the catalyst morphology. Our results suggest a practical recipe for catalyst nanoengineering controlling the chemical composition at the metal/oxide interface. Indeed, Ni atoms in contact with the oxide support reduce the binding energy of molecular oxygen at different adsorption sites.