Ni-Atom Induced Interface Water Reorientation around Ru Clusters for Alkaline Hydrogen Evolution Reaction

The sluggish water dissociation process in alkaline electrolytes severely hinders the kinetics of hydrogen evolution reaction (HER). It is well-established that a favorable orientation of H₂O molecules around catalyst facilitates the formation of the transition state structure and thereby accelerates water dissociation. However, controlling H₂O orientation remains challenging due to its random distribution. Herein, we propose a strategy of effectively modulating the interfacial water structure by manipulating the charge distribution of Ru cluster anchored on a N, B-doped carbon substrate through Ni atom doping. The strong interaction between B and Ru suppresses the aggregation of Ru species. While incorporation of Ni atoms modulates the charge distribution of Ru clusters and optimizes their electronic structure. This electronic modulation induces the reorientation of interfacial water hydrate (K⁺•H₂O) around Ru, thereby enhancing the interactions between them. Such interaction shortens the Ru-H distance, promotes the polarization of H─OH bond, and ultimately accelerates the water dissociation kinetics. As a result, the RuNi-NBC shows an ultralow overpotential of 17 mV at 10 mAcm^-2 current density and excellent stability after a 5 000-cycling test with a negligible decrease in 1.0 m KOH. This work provides a novel approach for manipulating H₂O dissociation to achieve superior HER electrocatalytic performance.