A Keggin Polyoxometalate Shows Water Oxidation Activity at Neutral pH: POM@ZIF‐8, an Efficient and Robust Electrocatalyst

Abstract Keggin‐type polyoxometalate anions [XM 12 O 40 ] n − are versatile, as their applications in interdisciplinary areas show. The Keggin anion [CoW 12 O 40 ] 6− turns into an efficient and robust electrocatalyst upon its confinement in the well‐defined void space of ZIF‐8, a metal–organic framework (MOF). [H 6 CoW 12 O 40 ]@ZIF‐8 is so stable to water oxidation that it retains its initial activity even after 1000 catalytic cycles. The catalyst has a turnover frequency (TOF) of 10.8 mol O 2 (mol Co) −1 s −1 , one of the highest TOFs for electrocatalytic oxygen evolution at neutral pH. Controlled experiments rule out the chances of formation and participation of CoO x in this electrocatalyic water oxidation.