One‐Step Scalable Production of Co1−xS/Graphene Nanocomposite as High‐Performance Bifunctional Electrocatalyst

Herein, a strategy for one‐step fabrication of cobalt sulfide/graphene (Co 1− x S/G) nanocomposite as bifunctional catalyst for oxygen catalysis is demonstrated. The one‐step fabrication method involves annealing the mixture of cobalt salt, thioacetamide, and graphene oxide with the assistance of small amount of glycol without any further purification steps. The Co 1− x S/G shows a morphology with small‐sized Co 1− x S nanocrystals strongly and uniformly anchored on the graphene surface. Systematically electrochemical studies demonstrate that the Co 1− x S/G with optimized components shows superior catalytic activities toward oxygen reduction and oxygen evolution, which are comparable or even superior to commercial Pt/C and Ir/C catalysts. As a result, the potential hysteresis of Co 1− x S/G is the lowest among all the samples. The facile operability of the fabrication method and the high bifunctional activity of Co 1− x S/G may pave one practical way for broad applications including fuel cell, metal‐O 2 battery, and water electrolysis.