Flexible photothermal-triggered MOF-composite nanofibers textures for freshwater harvesting with high efficiency and stability

Abstract

Vast freshwater reserves in the atmosphere have been investigated as a sustainable source of water for the alleviation of the water crisis with suitable sorbent-based atmospheric water harvesting (AWH) materials. In this work, we design a flexible photothermal-triggered MOF-composite nanofiber texture (PMNT), which is fabricated by combining nanofibers to be optimally integrated with UiO-66-NH2, carbon black and lithium chloride. PMNT achieves not only efficient water molecule uptake but also high solar thermal conversion efficiency. The PMNT effectively harvests atmospheric water to ∼ 1.44 g g−1 under 60 % RH in 80 min and quickly releases water over 30 min under 1 sun. In particular, PMNT outdoors collects water of ∼ 1.16 g g−1, even if the light intensity is ∼ 1.16 kW m−2 and the temperature is ∼ 34 °C, the RH is only 23 %. PMNT outdoors can achieve a total water yield of ∼ 4.61 g g−1 through 5 uptake-release cycles per day, along with stability and low energy consumption for AWH. It has been demonstrated that the as-harvesting water via PMNT meets the WHO standard. This study provides insight into the design of novel materials for AWH performance, which can be extended to practical applications, e.g., water engineering in arid regions, water harvesting devices and systems in industry.