Guang Li, Saiwei Luan, Jiajie Wu, Shengqi Zhang, Biao Wu, Z. Merrick Li, Lei Li, Qing Qu
ABSTRACT Coupling the adsorbate evolution mechanism (AEM) and lattice oxygen mechanism (LOM) for oxygen evolution reaction (OER), along with tuning interfacial water structure for hydrogen evolution reaction (HER), offers a promising yet underexplored strategy for achieving efficient and stable overall water splitting. Here, a zwitterion‐bearing small molecule is anchored at the FeNiOOH interface, making possible a tripartite synergy among AEM, LOM, and interfacial solvation dynamics. Operando spectroscopic and theoretical studies uncover a spatially separated dual‐path mechanism, where arginine‐induced N─M─O motifs activate the LOM pathway via enhanced covalency, while adjacent O─M─O units are electronically modulated to promote the AEM route. Additionally, hydrogen bonding between arginine and interfacial water disrupts the hydrogen‐bond network and increases the fraction of weakly bound water molecules, thereby facilitating water dissociation during HER. The Arg@FeNiOOH catalyst exhibits overpotentials of 271 mV (OER) and 222 mV (HER) at 500 mA cm − 2 , maintaining stability over 250 h. This work demonstrates a generalizable interfacial strategy that integrates dual‐pathway coexistence with interfacial water structure modulation to achieve efficient and durable alkaline water splitting.