Bioinspired Enzyme-Like Mechanism Enables Adaptive Local Charge Modulation for Blue Energy Harvesting

Enhancing the performance of ion-selective membranes is critical for achieving efficient osmotic energy conversion. However, existing charge-regulation strategies struggle to adapt to dynamically changing ion-transport environments. Inspired by natural cytochrome c oxidase (CcO), this work demonstrates that atomically precise heteronuclear FeCo dual-atom nanozymes (FeCo-DACs) can dynamically modulate the local charge distribution at active sites via an oxidase-like mechanism, thereby enhancing osmotic energy conversion. By tailoring the coordination environments of heteronuclear and homonuclear dual-atom sites, enzyme-like activity and ion selectivity are optimized. The bioinspired composite membrane incorporating Fe─Co bonded nanozymes directly into bacterial cellulose (BC/FeCo-DACs) achieves a power density of 15.4 W m^-2 during the mixing of natural river water and seawater, without external stimuli. Combined experimental and theoretical analyses reveal that the heteronuclear FeCo configuration, with an optimal metal-metal bond length, balances oxygen adsorption/desorption while establishing the most energetically favorable proton-consumption pathway, enabling spontaneous dynamic local charge regulation and improved osmotic energy conversion performance.