Hierarchical design of self-standing FeNi-based metallic glass by in-situ surface amorphous oxide construction for durable and efficient oxygen evolution

As the driving force to accelerate water electrolysis in commercialization, electrocatalysts concurrently satisfying electrocatalytic activity, mechanical flexibility and low cost are essential in the design to lower the kinetic barriers of oxygen evolution reaction (OER). Herein, we present a strategy to in situ construct amorphous metal oxide nanolayers on different compositions of self-standing non-precious FexNiyP20 (at.%) metallic glasses (AMO-MG). With the mechanical flexibility, the processed FexNiyP20 MGs, particularly at Fe30Ni50P20, reaches low OER overpotentials of 238 at a current density of 10 mA cm(-2) and a Tafel slope of 33 mV dec(-1) in 1.0 M KOH solution while preserving a long-term durability exceeding 60 h. Further studies indicate these robust OER activities appear to be directly linked with the unique surface patterns of the in situ formed AMO nanolayer providing abundant active sites, low charge transfer resistance and superior structural-integration. Modelling analysis further shows that both Fe and Ni sites in the AMO nanolayer act as active sites leading to a strong charge transfer for effective H2O adsorption and an optimization of rate-determining step of OER process. Such in situ AMO-MG hierarchical structure therefore provides a novel structure-integration strategy and win-win situation to design and commercialize high-performance alloy catalysts for OER.