Harnessing metal–ligand complex and photothermal conversion in hydrogels for advanced atmospheric water harvesting

Abstract

Atmospheric Water Harvesting (AWH) has emerged as a promising solution to mitigate global water crisis. The integration of hydrogels with hygroscopic salts significantly enhances the performance of AWH materials. However, the leakage and aggregation of hygroscopic salts within the hydrogel matrix present considerable challenges, compromising structural stability and long-term performance, which ultimately limits their practical applications. This study presents a method for incorporating salt ions into hydrogel substrates through ion–ligand coordination. The strong bonding ensures a uniform distribution of ions on the hydrogel pore surfaces, while open metal sites significantly enhance water adsorption. Moreover, the stable coordination structure prevents ion migration, improving material stability. The study further examines the liquefied water state, water evaporation enthalpy, and the kinetics and thermodynamics of water desorption in the composite AWH material. These findings offer valuable insights into enhancing the performance of AWH materials and contribute to the development of practical solutions for global water scarcity.