Oxygen Reduction Reaction Activity of Pt/Ni/Pt(111) Well-defined Model Catalyst Surfaces

In this study, wWe have investigated the oxygen reduction reaction (ORR) activity of Pt/Ni/Pt(111) model catalyst surfaces prepared by molecular beam epitaxy. Compared with Pt(111), The 1–-4- monolayers (MLs)-thick Pt on Ni/Pt(111) surfaces showed 9-, 12-, 8-,, and 7-fold higher activities, respectively than that of Pt(111). Cyclic voltammetry measurements and X-ray photoelectron spectroscopic analysis clearly revealed that electrochemical as well asand electronic properties of the surface Pt(111) surface lattice approach those ofcome close to clean Pt(111) surface with increasing Pt’s surface layer thickness. The results demonstratedexhibited that tuning Pt shell thickness is a key for generating highly- active Pt-bimetallic catalysts of for ORR.