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.