Electron-Enriched Ru Nanoclusters Mediating Surface Reconstruction of Phosphide Catalysts for Efficient Water Electrolysis.

Abstract

Transition metal phosphides (TMPs) are attractive bifunctional electrocatalysts for alkaline water electrolysis. However, their practical deployment is hindered by a fundamental reconstruction paradox. Electron-rich metal-phosphorus frameworks are intrinsically favorable for the hydrogen evolution reaction (HER), whereas efficient oxygen evolution reaction (OER) requires rapid in situ conversion into high-valence metal (oxy)hydroxides-a transformation that is typically kinetically sluggish in conventional TMPs. Here, we report a dynamic pre-catalyst architecture in which electron-enriched Ru nanoclusters are anchored at the interfaces of bimetallic FeCo phosphides (Ru-FeCoP@NF). The Ru nanoclusters act as localized, potential-responsive electron reservoirs, extracting and redistributing electrons from adjacent Fe/Co sites via interfacial charge-transfer pathways. This interfacial electron-pump effect selectively destabilizes the metal-phosphorus framework, markedly reducing the kinetic barrier for OH^--induced surface reconstruction and enabling the early emergence of catalytically active FeCo (oxy)hydroxide species. Consequently, the catalyst maintains an electron-rich metallic state conducive to HER while simultaneously accelerating dynamic surface evolution for OER. When integrated into an anion exchange membrane water electrolyzer, Ru-FeCoP@NF achieves 1.0 A cm^- ² at 1.77 V for 300 h in 1.0 M KOH at 80°C, delivering industrially relevant efficiency and operational durability.