Multifunctional Solar Waterways: Plasma-Enabled Self-Cleaning Nanoarchitectures for Energy-Efficient Desalination

摘要

Evaporating seawater and separating salt from water is one of the most promising solutions for global water scarcity. State-of-the-art water desalination devices combining solar harvesting and heat localization for evaporation using nanomaterials still suffer from several issues in energy efficiency, long-term performance, salt fouling, light blocking, and clean water collection in real-world applications. To address these issues, this work devises plasma-enabled multifunctional all-carbon nanoarchitectures with on-surface waterways formed by nitrogen-doped hydrophilic graphene nanopetals (N-fGPs) seamlessly integrated onto the external surface of hydrophobic self-assembled graphene foam (sGF). The N-fGPs simultaneously transport water and salt ions, absorb sunlight, serve as evaporation surfaces, then capture the salts, followed by self-cleaning. The sGF ensures effective thermal insulation and enhanced heat localization, contributing to high solar-vapor efficiency of 88.6 +/- 2.1%. Seamless connection between N-fGPs and sGF and self-cleaning of N-fGP structures by redissolution of the captured salts in the waterways lead to long-term stability over 240 h of continuous operation in real seawater without performance degradation, and a high daily evaporation yield of 15.76 kg m(-2). By eliminating sunlight blocking and guiding condensed vapor, a high clean water collection ratio of 83.5% is achieved. The multiple functionalities make the current nanoarchitectures promising as multipurpose advanced energy materials.