Facile synthesis of Fe-doped Co9S8 nano-microspheres grown on nickel foam for efficient oxygen evolution reaction

Cobalt sulfides have drawn enormous attention as earth-abundant alternatives to precious-metal electrocatalysts capable of catalyzing oxygen evolution reaction (OER) in alkaline medium. Although significant progresses have been realized in the development of various composite modulation to improve their properties for oxygen evolution, to boost their poor catalytic activity for oxygen evolution reaction is still challenging, which unambiguously limits the wide utilization of cobalt sulfides. Here, we present the facile growth of metal-doping (Fe, Ni) into Co9S8 supported on nickle foam (NF) through a one-step simple hydrothermal process. The effect of (Fe, Ni)-doping on the morphology and the catalytic activity of Co9S8 has been thoroughly investigated. Fe-Co9S8 nano-microspheres supported on NF (Fe-Co9S8 NM/NF) have been obtained with the remarkable electrocatalytic activity, which only requires a lower overpotential of 270 mV to reach a current density of 10 mA cm−2 and exhibits the smaller Tafel slope of 70 mV dec−1 as well as robust stability. The excellent OER performance of Fe-Co9S8 NM/NF could be attributed to the synergistic interaction of Fe dopants with Co9S8 nano-microspheres and faster charge transfer rate derived from NF support. This work provides a new and effective way to design metal-doped Co9S8-based heterostructures supported on conductive support as efficient OER electrocatalysts.