Ultrathin MoS2 wrapped N-doped carbon-coated cobalt nanospheres for OER applications

Abstract

The possibilities to resolve the exponential increase in energy demand using water splitting have also triggered huge worldwide attention towards the oxygen evolution reaction using an efficient, earth-abundant and low-cost electrocatalyst. Transition metal sulfides have been established as an excellent hydrogen evolution reaction catalyst but their oxygen evolution reaction behaviour is still little explored and needs further investigations. The oxygen evolution reaction has huge potential for fuel cell and metal–air battery applications. Herein MoS₂ nanolayers having interlayer spacing were hierarchically grown over N-doped carbon wrapped cobalt nanospheres derived from a cobalt-based metal–organic framework. The catalyst Co@NC@MoS₂ has a low overpotential of 297 mV vs. RHE at a 10 mA cm⁻² current density. The catalyst has long term stability with a Tafel slope value of 70 mV dec⁻¹. A chronoamperometric study for more than 10 hours does not show any significant change in the current density of the catalyst.