Co1−xS-Graphene Hybrid: A High-Performance Metal Chalcogenide Electrocatalyst for Oxygen Reduction

A hybrid electrocatalyst for the oxygen reduction reaction (ORR), consisting of Co1−xS nanoparticles directly nucleated and grown on sheets of reduced graphene oxide (RGO; see SEM image), was prepared by a mild solution‐phase reaction followed by an annealing step. The Co1−xS–RGO hybrid has the highest catalytic performance of all cobalt chalcogenide based ORR catalysts, as revealed inter alia by measurements with a rotating‐disk electrode (see picture; RHE = reversible hydrogen electrode).