Synergistic Interfacial Evaporation and Electricity Generation Enabled by Fe-Co PBA Derived Nature Sponges

Abstract

Solar-powered interfacial evaporation has gained prominence as a sustainable and low-energy-consumption approach to desalinate seawater. However, while evaporation occurs at the interface, the energy generated is not fully utilized. To address this issue, we propose an integrated strategy combining interfacial evaporation with evaporation-driven power generation. In selecting precursors, we focused on natural sponges as a biomass material, ingeniously leveraging their dense, abundant pore network and carbon-based properties. By loading iron-cobalt Prussian blue-like compounds (PBAs) onto the sponge and subjecting it to carbonization, we created a material with both high light absorption and conductivity. The resulting sponge-based evaporator demonstrated high stability, large specific surface area, and efficient performance, achieving an evaporation rate of 2.91 kg·m⁻²·h⁻¹ in a 3.5% NaCl solution under 1 sun illumination. Simultaneously, the device achieved efficient power generation, maintaining a stable voltage output of approximately 315 mV for 7 hours at 60% relative humidity. Furthermore, the system removed 99.6% of major metal ions (Na⁺, Mg²⁺, Ca²⁺, K⁺), producing high-purity freshwater. This study proposes a sustainable and carbon-neutral conversion strategy for waste biomass, establishing a high-performance hybrid system that provides a win-win solution for simultaneous freshwater and electricity production.