PtRu Alloying‐Mediated Reconstruction of Adsorption‐Conversion Landscape and Interfacial Water for Durable Alkaline Hydrogen Evolution

Abstract

Renewable‐powered water electrolysis is pivotal to sustainable hydrogen production, yet the alkaline hydrogen evolution reaction (HER) remains kinetically sluggish at high current densities. This limitation stems not only from the extra water‐dissociation step, but also from an unfavorable interfacial water microenvironment that hampers charge transport—challenges that become even more pronounced at ultralow noble‐metal loadings. Herein, an ultralow‐loading PtRu alloy nanocluster catalyst on heterophase MoO x (PtRu/MoO x ) synthesized by ultrafast flash Joule heating (FJH) is reported. This nonequilibrium thermal shock drives PtRu alloying, preserves a defect‐rich interface, and establishes a pronounced electronic metal‐support interaction (EMSI) that renders the alloy surface electron‐deficient. Operando spectroscopy and density functional theory (DFT) calculations reveal that this electron‐deficient surface strengthens water adsorption, balances water dissociation with intermediate conversion, and promotes the evolution of interfacial water from isolated, cation‐dominated motifs into a surface‐coupled, hydrogen‐bond‐connected network. Consequently, PtRu/MoO x requires only 56.15 mV to reach 100 mA cm −2 in 1 M KOH; as the cathode in an anion exchange membrane water electrolyzer, it achieves 1.836 V at 1.0 A cm −2 and operates stably for over 2000 h at 0.5 A cm −2 . This work provides a viable strategy for ultralow‐loading cathodes by synergistically coupling alloying‐governed reaction energetics with interfacial‐water microenvironment engineering.