Iron-based sulfides for efficient oxygen precipitation reactions: Fe2.25S/NF

Designing high-performance, long-lasting, and affordable non-precious metal catalysts as alternatives to noble metal counterparts plays a critical role in promoting large-scale water electrolysis for hydrogen production. Fe-based sulfidic electrocatalytic materials, with their rich Fe-Fe and Fe-S bonds, promote oxygen and hydrogen precipitation reactions effectively, and possess advantages such as large reserves and low cost. Thus, we developed the Fe 2.25 S/NF monometallic iron-based sulfide electrocatalyst on an electrically conductive nickel foam substrate via a single-step hydrothermal process. Notably, Fe 2.25 S/NF achieved 10 mA cm ‐2 current density with an OER overpotential of just 259 mV in 1 M KOH solution. The superior catalytic activity of Fe 2.25 S/NF stems from its flower-like nanostructure, which creates a large surface area interface and provides abundant active sites for effective charge transfer during electrocatalysis, thereby markedly enhancing reaction kinetics.