Pivotal Role of Geometry Regulation on O−O Bond Formation Mechanism of Bimetallic Water Oxidation Catalysts
Qi‐Fa Chen, Ke‐Lin Xian, Hongtao Zhang, Xiaojun Su, Rong‐Zhen Liao, Ming‐Tian Zhang
Abstract
Abstract In this study, we highlight the impact of catalyst geometry on the formation of O−O bonds in Cu 2 and Fe 2 catalysts. A series of Cu 2 complexes with diverse linkers are designed as electrocatalysts for water oxidation. Interestingly, the catalytic performance of these Cu 2 complexes is enhanced as their molecular skeletons become more rigid, which contrasts with the behavior observed in our previous investigation with Fe 2 analogs. Moreover, mechanistic studies reveal that the reactivity of the bridging O atom results in distinct pathways for O−O bond formation in Cu 2 and Fe 2 catalysts. In Cu 2 systems, the coupling takes place between a terminal Cu III −OH and a bridging μ −O⋅ radical. Whereas in Fe 2 systems, it involves the coupling of two terminal Fe–oxo entities. Furthermore, an in‐depth structure–activity analysis uncovers the spatial geometric prerequisites for the coupling of the terminal OH with the bridging μ −O⋅ radical, ultimately leading to the O−O bond formation. Overall, this study emphasizes the critical role of precisely adjusting the spatial geometry of catalysts to align with the O−O bonding pathway.