Bioinspired Homonuclear Diatomic Iron Active Site Regulation for Efficient Antifouling Osmotic Energy Conversion

Abstract Membrane‐based reverse electrodialysis is globally recognized as a promising technology for harnessing osmotic energy. However, its practical application is greatly restricted by the poor anti‐fouling ability of existing membrane materials. Inspired by the structural and functional models of natural cytochrome c oxidases (CcO), the first use of atomically precise homonuclear diatomic iron composites as high‐performance osmotic energy conversion membranes with excellent anti‐fouling ability is demonstrated. Through rational tuning of the atomic configuration of the diatomic iron sites, the oxidase‐like activity can be precisely tailored, leading to the augmentation of ion throughput and anti‐fouling capacity. Composite membranes featuring direct Fe‐Fe motif configurations embedded within cellulose nanofibers (CNF/Fe‐DACs‐P) surpass state‐of‐the‐art CNF‐based membranes with power densities of ca. 6.7 W m⁻² and a 44.5‐fold enhancement in antimicrobial performance. Combined, experimental characterization and density functional theory simulations reveal that homonuclear diatomic iron sites with metal‐metal interactions can achieve ideally balanced adsorption and desorption of intermediates, thus realizing superior oxidase‐like activity, enhanced ionic flux, and excellent antibacterial activity.