Hollow core supported Pt monolayer catalysts for oxygen reduction

We synthesized high-activity electrocatalysts for the oxygen reduction reaction comprising a Pt monolayer shell on compact hollow nanoparticles. Pulse electrodeposited Ni nanoparticles were replaced galvanically by Pd and Pd-Au ions to obtain corresponding hollow nanoparticles. Pt monolayer catalysts supported on such hollow cores exhibited total-metal mass activities ranging from 0.41 to 0.57 A mg(-1), doubling that of 0.25 A mg(-1) for Pt monolayer catalysts on solid Pd cores. We attribute this enhanced activity to the smooth surface morphology and hollow-induced lattice contraction, in addition to the mass-saving geometry of hollow particles. (C) 2012 Elsevier B.V. All rights reserved.