Preparation of 3D nanostructured MnCo2S4 as a robust electrocatalyst for overall water splitting

Abstract

AbstractThe exploitation and use of efficient and inexpensive electrochemical catalysts accelerate overall water splitting, which rapidly produces oxygen and hydrogen. In this work, MnCo2S4 is grown on nickel foam by a two‐step method, hydrothermal and sulfuration method. Experiments have shown that the resulting MnCo2S4/NF exhibits a low overpotential of 310 mV to achieve a current density of 50 mA cm−2 in 1.0 M potassium hydroxide for oxygen evolution reaction (OER). In addition, the MnCo2S4/NF exhibits a low overpotential of only 167 mV at 10 mA cm−2 for hydrogen evolution reaction (HER). Furthermore, MnCo2S4/NF is acted as a bifunctional water splitting catalyst, and in 1.0 M potassium hydroxide, in order to maintain a current of 10 mA cm−2, a low battery voltage of 1.61 V is required. The nanostructure, which provides a large specific surface area, which in turn increases the reactive sites, facilitates contact of large areas of water with the catalyst, and rapid transfer of electrons. At the same time, through a series of characterization (XRD, SEM and XPS), it is proved that the catalyst is efficient and stable under alkaline condition.