Title High Solar-Thermal Conversion Aerogel for Efficient Atmospheric Water Harvesting

The shortage of freshwater is a global problem, however, the gel that can be used for atmospheric water harvesting (AWH) in recent years studying, suffer from salt leakage, agglomeration, and slow water evaporation efficiency. Herein, a solar-driven atmospheric water harvesting (SAWH) aerogel is prepared by UV polymerization and freeze-drying technique, using poly(N-isopropylacrylamide) (PNIPAm), hydroxypropyl cellulose (HPC), ethanolamine-decorate LiCl (E-LiCl) and polyaniline (PANI) as raw materials. The PNIPAm and HPC formed aerogel networks makes the E-LiCl stably and efficiently loaded, improving the water adsorption-desorption kinetics, and PANI achieves rapid water vapor evaporation. The aerogel has low density approximate to 0.12-0.15 g cm-3, but can sustain a weight of 1000 times of its own weight. The synergist of elements and structure gives the aerogel has 0.46-2.95 g g-1 water uptake capability at 30-90% relative humidity, and evaporation rate reaches 1.98 kg m-2 h-1 under 1 sun illumination. In outdoor experiments, 88% of the water is harvesting under natural light irradiation, and an average water harvesting rate of 0.80 gwater gsorbent-1 day-1. Therefore, the aerogel can be used in arid and semi-arid areas to collect water for plants and animals. The porous structure of SMPH allows for efficient and stable loading of hygroscopic salts, which improve the aerogel water harvesting kinetics. In addition, the directional pore structure makes for high water vapor evaporation capacity. This synergist of elements and structure gives the aerogel has efficient and sustainable water harvesting around the clock.image