Monodisperse Palladium Sulfide as Efficient Electrocatalyst for Oxygen Reduction Reaction.

In this study, we report a colloidal synthesis of palladium sulfides (including Pd16S7, Pd4S, and PdS) via a facile one-pot hot-solution synthetic route and their promising application as electrocatalyst for the oxygen reduction reaction (ORR). Among the different palladium sulfides tested, monodisperse Pd4S nanoparticles exhibit the best electrocatalytic activity toward ORR in alkaline medium, with the half-wave potential ca. 47 mV more positive than that of the state-of-the-art Pt/C catalyst. Density functional theory calculations indicate the existence of oxygen absorption sites in Pd4S surface result in optimized oxygen-binding ability for the four-electron oxygen reduction.