Discovering the pH‐independent Oxygen–Oxygen Formation via Direct Mn‐oxo Coupling

Abstract

ABSTRACT Unraveling the mechanism of O─O bond formation on metal‐oxo is critical yet remains a central challenge in electrocatalytic water oxidation. Herein, we show the pH‐independent O─O bond formation pathway in edge‐shared dual [MnO 6 ] motifs. By manipulating the atomic‐scale connectivity of [MnO 6 ] units, two structurally well‐defined sodium manganese pyrophosphate compounds with edge‐sharing (Mn‐edge) and corner‐sharing (Mn‐corner) [MnO 6 ] octahedral configurations were synthesized with similar chemical composition and morphology, except that the Mn ∼ Mn distance in Mn‐edge is significantly shorter than that in Mn‐corner. Electrochemical and spectroscopic analyses reveal that Mn‐edge exhibits an unprecedented pH‐independent evolution of O 2 . Isotope‐labeling experiments and in situ Raman spectroscopy identify a direct coupling mechanism between Mn−O species in Mn‐edge, bypassing the conventional nucleophilic water attack. Density functional theory calculations further support that Mn‐oxo coupling between asymmetric Mn VI  ∼ Mn V centers drastically reduces the energy barrier for O─O bond formation. These findings establish the connectivity of [MnO 6 ] as a critical descriptor for water oxidation mechanism and offer a new design strategy for efficient catalysts inspired by natural oxygen‐evolving complexes.