Controlling Oxidation Reaction on Platinum by Spin Manipulation

M.C. Sison Escaño, T.Q. Nguyen, H. Nakanishi, H. Kasai
Osaka University, JP

Keywords: oxygen, platinum, spin, DFT, Monte-Carlo simulation, bonding, atomic structure


Oxidation of metal surface is of outstanding practical importance in microelectronics, energy conversion systems and environmental devices. As an oxidation catalyst, platinum (Pt) is widely used in chemical and automotive industries. Thus far, the dissociative adsorption of oxygen on Pt crystalline surfaces is activated. Ways to reduce the barrier have long been existing, for instance using strain and ligand effects, albeit, lower barrier always leads to a strongly bound oxygen atom on surface, which is often undesirable. Our present work introduces a novel means to achieve facile oxygen dissociation and a weakly bound dissociated oxygen atom, simultaneously on Pt surface, by changing the magnetic state of Pt layer (paramagnetic to ferromagnetic) via Pt/M (M: Fe,Co). Atomistic modeling based on spin-polarized density functional theory (SDFT) and Monte-Carlo simulation reveals emergence of non-activated dissociation on Pt/Fe and a high temperature Pt layer phase transition. The Fermi-level density of states was found to be an appropriate basis for the reactivity mechanism. The fast dissociation of oxygen on Pt/M as compared to Pt has been experimentally observed.