A Ligand‐Assisted Hydrothermal–Molten Salt Strategy for Scalable Synthesis of Defect‐Rich Two‐Dimensional NiMo Oxide Toward Industrial‐Grade Hydrogen Evolution

Developing cost‐effective, stable electrocatalysts that operate reliably at industrial‐grade current densities remains a critical challenge for the alkaline hydrogen evolution reaction (HER). Herein, we report a ligand‐assisted hydrothermal–molten salt processing (LA‐HMSP) strategy for the synthesis of defect‐rich two‐dimensional layered NiMo oxide (NiMo‐LDO). The molten salt step induces topochemical reconstruction that generates abundant structural defects while preserving the layered architecture, leading to optimized electronic structure and strengthened Ni–Mo synergy. The resulting NiMo‐LDO exhibits exceptional HER performance in 1 M KOH, achieving an ultrahigh current density >3853 mA cm −2 (potential of −0.7 ~ 0 V), a low overpotential of 342 mV at 500 mA cm −2 , and stable operation for over 200 h—surpassing Pt/C and the hydrothermal‐only counterpart (NiMo‐HT). In situ Raman spectroscopy reveals reversible surface reconstruction and sustained water activation during operation. Density functional theory (DFT) calculations identify defect‐modulated Mo sites with near‐optimal hydrogen adsorption free energy (Δ G _H* ≈ 0.15 eV) as the key active centers. When integrated into an anion exchange membrane water electrolyzer (AEMWE), NiMo‐LDO delivers a current density of 0.5 A cm −2 at 1.95 V. This work provides a generalizable synthesis route that decouples morphological control and defect engineering, offering a viable pathway toward industrially applicable layered oxide electrocatalysts.