Nanoporous metallic-glass electrocatalysts for highly efficient oxygen evolution reaction

High anode overpotential of the oxygen evolution reaction (OER) restricts the upscale applications of water electrolysis. We attempt to address such technical challenges through the design and preparation of a group of nanoporous (Fe–Ni–Co)-based metallic glasses (NP–FeNiCo-MGs) as electrocatalyts of OER. The nanoporous structure is yielded through electrochemical selective dissolution of active Fe solid solution phase in free-surface layer of (Fe–Ni–Co)-based amorphous-nanocrystalline alloys (FeNiCo-ANs). Electrochemical tests reveal that integral composite electrodes combining with a catalytic layer of NP-FeNiCo-MGs and a current collector of FeNiCo-ANs exhibit high catalytic activity towards water oxidation in 1 M KOH solutions, which only requires an overpotential of 274 mV to yield a current density of 10 mA cm⁻². Studies of electrochemical states and electrode-electrolyte reaction process of the NP-FeNiCo-MGs during OER unveil plausible working mechanisms driving such promising catalytic activities. Based on the merits of a broad tunable range of compositions of active elements for OER, homogeneous distribution of metastable atoms, and high-surface-area nanoporous structure strongly combining with high-conductive substrate, the proposed nanoporous metallic-glass composite electrodes are of great significance for a variety of applications for clean energy.