Natural and Artificial Mn 4 Ca Cluster for the Water Splitting Reaction.

The oxygen-evolving center (OEC) in photosystem II (PSII) is a unique biological catalyst that splits water into electrons, protons, and O2 by using solar energy. Recent crystallographic studies have revealed that the structure of the OEC is an asymmetric Mn4 Ca cluster, which provides a blueprint to develop man-made water-splitting catalysts for artificial photosynthesis. Although it is a great challenge to mimic the whole structure and function of the OEC in the laboratory, significant advances have recently been achieved. In this Minireview, recent progress on mimicking the natural OEC is discussed. New strategies are suggested to construct more stable and efficient new generation of catalytic materials for the water splitting reaction based on the artificial Mn4 Ca cluster in the future.