Assembly of Fe7S8 and Co9S8 nanosheets coupled with Cu(OH)2 nanorods as highly efficient oxygen evolution catalyst

Abstract

Traditional fossil fuels can be replaced with hydrogen, and electrolysis of water is thought to be one of the most efficient ways to produce hydrogen that is also pollution-free. The oxygen evolution reaction (OER), which is thought to be the bottleneck of the entire water decomposition, is a result of the intricate electrochemical mechanism and the slow kinetic process. In this paper, Cu(OH)2 forerunners with nanorods structure were combined on copper froth by straightforward submersion technique. Then, in a standard three-electrode system Fe7S8 and Co9S8 nanosheets with 3D structures were assembled on Cu(OH)2 precursors by electrodeposition. At an alkaline environment of 1 M KOH, Cu(OH)2/CF requires an overpotential of only 235 mV when the current density reaches 10 mA cm−2, which is lower than that of other reported catalysts. In addition, Fe7S8–Co9S8@Cu(OH)2/CF also showed excellent OER performance after long-term stability test, because bimetallic synergism can adjust the electronic structure of the catalyst and optimize its electrical conductivity. A feasible method for the design of a highly efficient oxygen evolution catalyst based on copper foam is reported in this paper.