Three-dimensional crumpled reduced graphene oxide/Co9S8 nanocomposites as efficient electrocatalyst for oxygen evolution reaction

Abstract

Cobalt based electrocatalysts for oxygen evolution reaction (OER) have better OER activities than other transition metals and have attracted great interest in the development of efficient and economic catalysts. However, rational design and manufacture of OER catalysts for further enhancing the electrochemical activity and durability are still challenging, which significantly limits their practical utilization. Herein, novel three-dimensional reduced graphene oxide/Co9S8 composites (Co9S8/rGO) are constructed by a facile strategy of ultrasonic spray drying assisted with sequential heat treatment process. Such crumpled structure possesses extraordinary synergistic effects between the two components of Co9S8 and rGO. The optimal sample exhibits ultra-low overpotential of 0.308 V, Tafel slope of 130.0 mV dec−1 at the current density of 10 mA cm−2, as well as excellent cycling stability in 1 M KOH. The superior catalytic activity of the crumpled Co9S8/rGO composite is attributed to its unique structure including large surface area and abundant sites for potential catalysis. This work provides a potential large-scale strategy to prepare cobalt sulfides based OER electrocatalysts and realize the development of the energy research for the generation of hydrogen from water.