Tuning the morphological and electronic structure of amorphous nickel-based electrocatalysts by anion regulation for water oxidation in neutral media

Abstract

Water oxidation in near-neutral media is benign and environmentally friendly for water splitting and microbial electrolysis. Herein, various self-supporting amorphous Ni-based neutral water oxidation electrodes were fabricated by anion regulation. Among them, the Ni(OH)₂/Ni:Pi electrode only needs an overpotential of 340 mV to deliver 10 mA cm⁻² at pH 7.2. Stability tests show that its activity is maintained for at least 5000 s at a high current density (10 mA cm⁻²). This study demonstrates that high valence state Ni atoms and the Ni:Pi component are responsible for its high activity and stability, respectively.