Monodisperse Palladium Sulfide as Efficient Electrocatalyst for Oxygen Reduction Reaction

In this study, we report a colloidal synthesis of palladium sulfides (including Pd 16 S 7, Pd 4 S, 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 Pd 4 S 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 Pd 4 S surface result in optimized oxygen-binding ability for the four-electron oxygen reduction.