Octahedral Au-core Pt-shell (Au@Pt) nanoparticles were successfully prepared via a galvanic replacement of Cu
monolayer underpotentially deposited on Au core with a Pt monolayer. The visible light irradiation to Au@Pt
nanoparticles-immobilized electrodes enlarged a cathodic current of oxygen reduction reaction (ORR), suggesting that the
electrocatalytic activity of Pt shell layer was enhanced by the photoexcitation of localized surface plasmon resonance
peak of octahedral Au-core particles.