Construction of a MnCo2O4@NiyMx (S and P) crosslinked network for efficient electrocatalytic water splitting

Abstract

The preparation of stable, efficient and cost-effective electrocatalysts is a very good strategy for the production of hydrogen and oxygen by water splitting. A precursor material based on MnCo is directly grown on 3-dimensional hollow nickel foam through a simple hydrothermal synthesis method. The MnCo oxide presents a flake-like graded material with controllable morphology by varying the reaction time. Combined with the good catalytic performance of Ni₃S₂, the two components MnCo₂O₄ and Ni₃S₂ can produce synergistic effects in the water splitting process and improve the activity of the electrocatalysts. MnCo₂O₄@Ni₃S₂ presents superior catalytic activity and in order to achieve a current density of 40 mA cm⁻², an external voltage of 200 mV is required in 1 M KOH solution for the oxygen evolution reaction (OER) test. For the hydrogen evolution reaction (HER) test, an external voltage of only 110 mV is required in order to achieve a current density of 10 mA cm⁻². MnCo₂O₄@Ni₃S₂ is used as a fully hydrolyzed cathode and anode, and a cell voltage of 1.60 V is required in order to achieve a current density of 10 mA cm⁻² in an alkaline medium. Moreover, the material also exhibits good electrochemical stability; it does not decay when the current density is maintained for 15 h.