A Covalent Organic Framework/Graphene Dual-Region Hydrogel for Enhanced Solar-Driven Water Generation

Solar-driven water generation is a sustainable water treatment technology, helping to relieve global water scarcity issues. However, this technology faces great challenges due to the high energy consumption of water evaporation yielding low evaporation rates. Here, a covalent organic framework (COF)/graphene dual-region hydrogel, containing hydrophilic and hydrophobic regions in one material, is developed through a facile in situ growth strategy. The hydrophilic COF is covering parts of the hydrophobic graphene regions. Through accurate control of both wetting regions, the hybrid hydrogel shows effective light-harvesting, tunable wettability, optimized water content, and lowered energy demand for water vaporization. Acting as solar absorber, the dual-region hydrogel exhibits a steam generation rate as high as 3.69 kg m(-2) h(-1) under 1 sun irradiation (1 kW m(-2)), which competes well with other state-of-the-art materials. Furthermore, this hydrogel evaporator can be used to produce drinkable water from seawater and sewage, demonstrating the potential for water treatment.

Automated summary

A new material with dual-region hydrogel has been developed, which can effectively utilize solar energy, adjust wettability, and reduce energy demand for water evaporation. The material can generate steam at a high rate under solar irradiation and can be used to convert seawater and sewage into drinkable water, showing significant potential for water treatment.