Regenerable Catalyst for Highly Alkaline Water Oxidation

The iron-based catalysts are promising for the oxygen evolution reaction (OER) in alkaline media, yet the inherent dissolution of high-valent iron species induced performance decay during electrocatalysis remains a critical challenge. Herein, we present a robust iron-based catalyst (Fe-cat) that exhibits a fast ligand-induced regeneration ability, allowing for stable production of oxygen even in a 5.0 M NaOH electrolyte containing iron-2,2′-bipyrimidine (Fe-bpym). Using electrochemical methods and in situ UV–vis and electron paramagnetic resonance, we revealed the coordination configuration transition between the Fe-bpym in electrolytes and the Fe-cat on the electrode during the whole catalyst deposition-solution ligand repairing-catalyst regeneration process. The fast regeneration ability of the active Fe sites endures a long-term OER activity over 200 h with a low overpotential of 320 mV at 1.0 mA cm–2. This study provides an important strategy to design the robust OER catalysts through in situ regeneration of active metal sites on an electrode.