Dumbbell-like Pt−Fe₃O₄ Nanoparticles and Their Enhanced Catalysis for Oxygen Reduction Reaction

Monodisperse dumbbell-like Pt-Fe(3)O(4) nanoparticles are synthesized by epitaxial growth of Fe onto Pt nanoparticles followed by Fe oxidation. The nanoparticle size in the structure is tunable from 2 to 8 nm for Pt and 6 to 20 nm for Fe(3)O(4). Pt nanoparticles in the Pt-Fe(3)O(4) structure show a 20-fold increase in mass activity toward oxygen reduction reaction compared with the single component Pt nanoparticles and the commercial 3 nm Pt particles. The work proves that it is possible to maximize catalytic activity of the Pt nanoparticle catalyst through the control not only of Pt size and shape but also of its interaction with Fe(3)O(4) nanoparticles.