Porous hydrogel with intrinsic hydrophilicity and reduced vaporization

enthalpy has emerged as a rising star for solar-driven interfacial water

distillation and desalination. However, the development of facile, general and

scalable approaches capable of simultaneously engineering the molecular and

microporous structure is urgently needed for hydrogel evaporators but a

daunting challenge. Herein, a freeze-soak method based on Hofmeister effect is

used to fabricate porous hydrogel evaporators with tunable molecular and

microporous structure in large scale. The interconnected porous structure

endows the hydrogel with adjustable water transport rate and exceptional

desalination performance, while the changeable crystallinity allows the

hydrogel with tunable water states. Benefiting from these properties, the

hydrogel shows a high evaporation rate of 3.52 kg m-2 h-1

with the conversion efficiency of 97.2% under 1 Sun irradiation. Additionally,

the integration of the hydrogel evaporator with a thermoelectric module enables

the low-grade heat to electricity conversion. A power density of 0.65 W m-2

is achieved under 1 Sun irradiation. It is anticipated that the Hofmeister

effect-mediated porous hydrogel without the assistance of

freeze-drying will lay a solid foundation for the industrial fabrication of

hydrogel for energy conversion and storage, environmental remediation, etc.