Unveiling the Nickel–Manganese Sulfide Electrocatalyst for Enhanced Overall Alkaline Water Splitting

Abstract

Harnessing earth-abundant electrocatalysts for efficient water splitting is a key pursuit in the development of sustainable energy technologies. In this study, plate-like Nickel–manganese sulfide (NMS) was in situ grown on nickel foam, via a simple one-step hydrothermal approach, yielding a binder free electrocatalyst. The synergistic interplay between Ni and Mn in the sulfide matrix, combined with the conductive substrate, endows NMS with an exceptional bifunctional activity for overall water splitting in an alkaline medium. The NMS-based electrolyzer delivers a low cell voltage of 1.69 V at 10 mA/cm² and presents a remarkable stability over 150 h under 1 M KOH electrolyte. Notably, theoretical studies from density functional theory (DFT) strongly reinforce the experimental findings, highlighting NMS as a highly efficient bifunctional electrocatalyst. Thus, the viability of this system is positioned as a promising and scalable alternative to precious metal-based electrocatalysts.