Structural evolution of artificial water oxidation catalysts: From natural clusters to the design strategies of molecular systems

The development of artificial water oxidation catalysts (WOCs) represents a journey of structural and conceptual evolution. It began with bioinspired explorations of the Mn 4 CaO 5 cluster in Photosystem II, establishing core principles of molecular design based on precise control of metal nuclearity and coordination environments, and has now advanced towards a new generation of catalysts centered on earth-abundant metals. Throughout this progression, strategies such as multinuclear cooperativity and metal-ligand interactions have enabled base-metal catalysts to rival and even surpass the performance benchmarks set by their noble counterparts. To bridge the molecular precision of homogeneous catalysts with the operational stability required for practical applications, interfacial engineering has become paramount. Hybrid molecular electrodes, constructed through immobilization strategies that include π-π stacking and covalent anchoring, have emerged as representative paradigms that bridge the molecular and material realms. This review systematically delineates this structural evolution pathway. By integrating biological inspiration, molecular design, and interfacial engineering, it outlines a clear blueprint for developing efficient and stable sustainable water oxidation technologies.