Support‐Mediated Electronic Modulation of Ru Sites with Interfacial Water Network Reconstruction Toward High‐Efficiency Water Electrolysis

Rational regulation of the electronic environment of active sites is an effective strategy for improving water electrolysis kinetics. Herein, we report a P‐modified Ru‐doped NiMoO 4 nanoarray (Ru/P‐NMO) as a highly efficient bifunctional catalyst for overall water splitting. Experimental analyses and theoretical calculations demonstrate that phosphorus incorporation drives electron redistribution around Ru and tunes its d‐band center, thereby optimizing the adsorption energy of H 2 O and HER/OER intermediates. In situ Raman spectroscopy further shows a reorganization of the interfacial hydrogen‐bond network toward weakly hydrogen‐bonded water configurations, favoring interfacial water activation. As a result, Ru/P‐NMO exhibits outstanding HER and OER activities, requiring overpotentials of 11 and 231 mV to reach 10 mA cm −2 , respectively. In a two‐electrode system, Ru/P‐NMO delivers 10 mA cm −2 at a cell voltage of 1.51 V and maintains long‐term durability for 2000 h at 400 mA cm −2 . Furthermore, the Ru/P‐NMO‐based AEMWE achieves 1.0 and 2.0 A cm −2 at only 1.813 and 2.076 V, respectively, and exhibits stable operation at ampere‐level current density. This work provides a viable strategy for designing Ru‐based electrocatalysts toward energy‐efficient hydrogen production.