Fe-MOF derived Fe3O4/C-based hydrogel for efficient solar-driven photothermal evaporation

Solar-driven interfacial photothermal evaporation (SIPE) has been considered as a green and sustainable technology for obtaining fresh water, and the exploring efficient photothermal materials is crucial. Nanocomposite derived from metal-organic framework exhibits high light absorption properties and excellent chemical stability, making it an ideal candidate in the SIPE. Herein, Fe 3 O 4 /C nanocomposite was obtained using MIL-101 (Fe) as a precursor, and Fe 3 O 4 /C-based porous hydrogel (Fe 3 O 4 /C-PH) was subsequently prepared through chemical crosslinking foaming polymerization. The obtained Fe 3 O 4 /C-PH exhibited an evaporation rate of 3.33 kg m −2  h −1 under one sun intensity. Fe 3 O 4 /C-PH demonstrated outstanding desalination and salting out resistance when treating real seawater. Moreover, it could remove over 99 % of dyes from wastewater. The photothermal mechanisms are molecular thermal vibration of C component and semiconductor relaxation of Fe 3 O 4 . Meanwhile, the hydrophilic and porous skeleton structure of the hydrogel ensure Fe 3 O 4 /C-PH to transport water rapidly and exhibit good light absorption properties. This research broadens the candidate of photothermal materials for applications in SIPE, and also provides new avenues for desalination and wastewater purification.