Synthesis of three-dimensional Pd nanospheres decorated with a Pt monolayer for the oxygen reduction reaction

Pd@Pt nanoparticles with a three-dimensional (3D) nanospherical shape have been prepared using a two-step approach in which the Pd nanospheres are synthesized controllably by a solvothermal method, then a Pt monolayer is deposited on the Pd nanospheres using an underpotential deposition process. The Pd@Pt nanoparticles exhibit enhanced activity towards the ORR; the mass activity of Pt in the Pd@Pt nanospheres (1.03 A mgPt−1) is 3.3 times higher than that of commercial Pt/C (0.24 A mgPt−1).