Boosting Oxygen‐Evolving Activity via Atom‐Stepped Interfaces Architected with Kinetic Frustration

Abstract A highly active interface is extremely critical for the catalytic efficiency of an electrocatalyst; however, facilely tailoring its atomic packing characteristics remains challenging. Herein, a simple yet effective strategy is reported to obtain copious high‐energy atomic steps at the interface via controlling the solidification behavior of glass‐forming metallic liquids. By adjusting the chemical composition and cooling rate, highly faceted FeNi₃ nanocrystals are in situ formed in an FeNiB metallic glass (MG) matrix, leading to the creation of order/disorder interfaces. Benefiting from the catalytically active and stable atomic steps at the jagged interfaces, the resultant free‐standing FeNi₃ nanocrystal/MG composite exhibits a low oxygen‐evolving overpotential of 214 mV at 10 mA cm⁻², a small Tafel slope of 32.4 mV dec⁻¹, and good stability in alkaline media, outperforming most state‐of‐the‐art catalysts. This approach is based on the manipulation of nucleation and crystal growth of the solid‐solution nanophases (e.g., FeNi₃) in glass‐forming liquids, so that the highly stepped interface architecture can be obtained due to the kinetic frustration effect in MGs upon undercooling. It is envisaged that the atomic‐level stepped interface engineering via the physical metallurgy method can be easily extended to other MG systems, providing a new and generic paradigm for designing efficient yet cost‐effective electrocatalysts.