Multi‐Heterogeneous Interfaces Modulation of NiO/MoO₃/Fe₂O₃ for Enhanced Water/Seawater Splitting

Abstract The rational design of multi‐component heterostructures represents a promising strategy to overcome the intrinsic limitations of single‐phase Mo‐based electrocatalysts for water splitting. Herein, a ternary NiO/MoO₃/Fe₂O₃ heterostructure catalyst synthesized is reported via a facile chemical corrosion and annealing approach. The synergistic interplay between multiple heterogeneous interfaces induces significant electronic redistribution, optimizing adsorption energetics for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) intermediates. The catalyst achieves exceptional bifunctional performance, requiring ultralow overpotentials of 395 mV (HER) and 370 mV (OER) at industrial‐grade current density (1 A cm⁻²) in alkaline media, surpassing benchmark Pt/C and RuO₂. Notably, the ternary interface configuration mitigates metal dissolution, ensuring long‐term stability in both freshwater and simulated seawater electrolytes. Through comprehensive experimental characterization and theoretical calculations, the dual‐channel electron transfer mechanism is elucidated, and complementary active‐site interactions are responsible for the enhanced kinetics. This work provides a blueprint for engineering high‐efficiency ternary electrocatalysts through interfacial modulation, advancing the development of practical water‐splitting systems.