Calcium Manganese(III) Oxides (CaMn2O4⋅x H2O) as Biomimetic Oxygen‐Evolving Catalysts

Biomimetic and efficient: Mixed calcium manganese(III) oxides (see structure; Ca green, Mn red, O white) with elemental compositions and structures mimicking the active site of photosystem II were found to be highly active catalysts for the oxidation of water to molecular oxygen. As for PS II, the presence of Ca2+ greatly enhances the catalyst performance in comparison to the related manganese-only system Mn2O3.