Catalytic and Surface‐Electrocatalytic Water Oxidation by Redox Mediator–Catalyst Assemblies

All-in-one assemblies containing single-site water oxidation catalysts (red and blue) and redox mediators (green and blue) act as stable, robust catalysts toward water oxidation, both in solution and anchored to metal oxide surfaces by phosphonate linkers on the mediator. More than 28 000 turnovers have been achieved with >95 % Faradaic efficiency for oxygen production without reduced catalytic activity.