Optimized nano-heterojunction and hydrophilic carbon cloth for efficient solar driven Dual-Mode desalination and hydroelectricity co-generation

Solar-driven desalination stands as a vital approach to addressing the freshwater crisis, with the potential to harness the water flow during evaporation to induce hydroelectric generation. The key to enhancing the efficiency and stability of this co-generation technology lies in the simultaneous maintenance of rapid evaporation and robust water transport. Here, an advanced evaporation-hydroelectric generator is developed by integrating a hydrophilic carbon cloth with a structure-optimized Cs 0.32 WO 3 /Cu x S nano-heterojunction. Importantly, both experimental data and density functional theory calculations indicate that the heterojunction design and increased defect state atoms facilitate carrier mobility and non-radiative recombination, thus boosting photothermal performance. Furthermore, the modified hydrophilic carbon cloth, which is optimized in thickness, ensures a sustained water supply and establishes a significant ionic concentration gradient. The device achieves a high open-circuit voltage, rapid evaporation rate and stability in highly concentrated brines. Notably, the generated electricity can sufficiently drive an interconnected electrochemical desalination unit, enabling continuous dual-mode separation of water and salt. The system relies on solar energy to drive an innovative coupling of photothermal evaporation and hydroelectricity, representing a significant step forward in the development of highly efficient and sustainable technologies for the cogeneration of freshwater and clean energy.