Engineering the Heterogeneous Interface of Sulphur Doped Nickel-Manganese Oxide for Efficient Overall Electrochemical Water Splitting

Abstract

Electrochemical water splitting is the technique to utilize stochastic renewable sources for a continuous uninterrupted supply of energy through the production of hydrogen fuel. However, the performance of a water electrolyzer is limited due to the instability as well as larger overpotential associated with the current state of the electrocatalysts. Transition metal oxides show remarkable potential for catalyzing water electrolysis. Among transition metal oxides, binary transition metal compounds exhibit the forte to replace the expensive and scarce noble-metal electrocatalysts. The engineering of hetero-interfaces between sulphur doped nickel and manganese oxide nanostructures has been systematically presented in our study. The difference in morphology too affects the catalytic activity of the samples owing to variable electrolyte interaction. The strategic development of these hetero-interfaces wields the electrocatalyst its superior bifunctional activity for catalyzing oxygen evolution reaction at an overpotential as low as 300 mV at 20 mA cm-2 current density and hydrogen evolution reaction at 280 mV at 10 mA cm-2 current density. The catalyst also delivered a stable current density for a long-term durability study without any significant loss in the performance.