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

We report a synthetic method to enhance the electrocatalytic activity of birnessite for the oxygen evolution reaction (OER) by intercalating Ni2+ 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. Das Wasser zwischen den Schichten von Birnessit kann durch Ni2+‐Interkalation beeinflusst werden, um den Elektronentransfer und damit auch das Abschneiden als Katalysator der Sauerstoffentwicklung (OER) zu verbessern. Diese Ergebnisse sind auch für OER‐Katalysatoren mit anderen schichtförmigen oder nanoporösen Materialien von Interesse.