Hierarchical porous Fe3O4/Co3S4 nanosheets as an efficient electrocatalyst for the oxygen evolution reaction

Abstract

Transition-metal sulfides have attracted extensive interest as oxygen evolution reaction (OER) catalyst alternatives to noble metal based catalysts but generally exhibit limited electrocatalytic activity. We here report hierarchical porous Fe₃O₄/Co₃S₄ composite nanosheets for a highly efficient electrocatalytic OER in alkaline electrolytes. The preparation of the composite involves a hydrothermal synthesis and a subsequent sulfurization process. The prepared porous Fe₃O₄/Co₃S₄ composite shows strong synergetic coupling effects, facilitating active site exposure, and facile charge transfer. Remarkably, Fe₃O₄/Co₃S₄ nanosheets afforded an electrocatalytic OER with a current density of 10 mA cm⁻² at a low potential of 1.50 V and a small Tafel slope of about 56 mV dec⁻¹. This indicates that the composite of porous Fe₃O₄/Co₃S₄ nanosheets is promising as an efficient electrocatalyst for the OER that can be used in the fields of fuel cells, metal-air batteries and water splitting for hydrogen production.