Nickel Confined in the Interlayer Region of Birnessite: an Active Electrocatalyst for Water Oxidation

Abstract

Abstract We report a synthetic method to enhance the electrocatalytic activity of birnessite for the oxygen evolution reaction (OER) by intercalating Ni 2+ ions into the interlayer region. Electrocatalytic studies showed that nickel (7.7 atomic %)‐intercalated birnessite exhibits an overpotential ( η ) of 400 mV for OER at an anodic current of 10 mA cm −2 . This η is significantly lower than the η values for birnessite ( η ≈700 mV) and the active OER catalyst β‐Ni(OH) 2 ( η ≈550 mV). Molecular dynamics simulations suggest that a competition among the interactions between the nickel cation, water, and birnessite promote redox chemistry in the spatially confined interlayer region.