Ruthenium–Nickel Nanoparticles with Unconventional Face‐Centered Cubic Crystal Phase for Highly Active Electrocatalytic Hydrogen Evolution

Abstract Ru‐based nanomaterials are promising alternatives to Pt electrocatalysts for green hydrogen energy generation, and crystal phase engineering holds the key to unlocking their catalytic potential to new heights. However, controllable phase regulation on Ru‐alloys remains a formidable challenge, and unraveling the crystal phase‐related electrocatalytic performance is of great significance. Herein, RuNi nanoparticles are successfully synthesized with an unconventional face‐centered cubic ( fcc ) phase via a facile route. Comprehensive transmission electron microscopy confirmed the structural characteristics of the fcc ‐RuNi and electrochemical analyses indicate the impressive electrocatalytic hydrogen evolution reaction of fcc ‐RuNi. Notably, the anomalous fcc ‐RuNi nanoparticles possess an extraordinarily low overpotential of 16 mV in hydrogen evolution. Density functional theory calculations indicate that these nanoparticles are energetically conducive to intermediate desorption and H 2 O dissociation. This study enhances comprehension of phase regulation in Ru‐based nanostructures and will propel phase engineering in diverse catalytic applications.