writer：Qiang Luo, Tiance Zhang, Mingshuo Chen, Chang Gao, Li Guo, Maolin Zhou, Lingmei Zhu, Huijie Wei, Ass
keywords：Water harvesting
source：期刊
specific source：Small 2025, 21, 2503948
Issue time：2025年

Atmospheric water harvesting (AWH) is a promising strategy for freshwater

production to alleviate water scarcity, but it remains challenging due to its

limited daily water production volume at extremely low relative humidity

(RH). Herein, a super-hygroscopic composite (CHG) is reported that is

fabricated by using chitosan (CS), hyaluronic acid (HA), metal–organic

frameworks (MOF-303), graphene oxide (GO), and calcium chloride (CaCl2).

In this strategy, the CS-HA serves as a cation/anion substrate to form stable

hydrogel structure with CaCl2 salt. MOF-303 and GO exhibit a significantly

enhanced water harvesting capacity at low RH (≤30% RH). CaCl2 additionally

improves structural stability, firmly locking the MOF-303 and GO particles

into the entangled chain structure of the micro-gel network. The hydrophilicity

and porosity of CS-HA frameworks promote diffusion and storage of water

molecules, realizing the effective atmospheric moisture capture of the CHG.

The CHGrealizes a high-water uptake of ≈0.78 g g?1 at 20% RH, and after

absorbing water to saturation at 45% RH, it achieves ≈0.93 g g?1 in 120 min

under 0.50-sun illumination. Especially, CHG on a large scale displays a high

sorption-desorption efficiency, which achieves an excellent freshwater yield of

≈9.95 L kg?1 day?1 under ≈25% RH and temperature of ≈30 °Cviathe

self-made device. This work offers new insights into the design of

high-performance materials for AWH applications in water-lacking situations

or arid regions.

https://doi.org/10.1002/smll.202503948