A regulation strategy of sorbent stepwise position for boosting atmospheric water harvesting in arid area

Numerous studies have focused on tailoring materials for sorption-based atmospheric water harvesting (AWH) in arid climates, but both the design and modification of materials are a compromise for specific conditions and even sacrifice the nature of S-shaped isotherm. Inspired by the manipulation method of air humidity, we herein propose a regulation strategy of sorbent stepwise position by inducing an inner cooling source without changing the intrinsic properties of metal-organic framework (MOF). Significant improvement of water uptake of MIL-101(Cr) coating can be reached from 0.13 to 1.05 g/g with the cooling temperature of 14°C in typical arid climate (25°C and 30% relative humidity [RH]). Mechanism of stepwise position migration is elucidated and performance of AWH device based on Peltier cooler is enhanced as compared to that without regulation. This study weakens the limitation of the exclusive tailoring materials for specific conditions and would provide a promising perspective for next-generation scalable and variable weather-adaptive AWH systems. • Inner cooling source in adsorption promotes the migration of stepwise position • Water uptake of MIL-101(Cr) is enhanced to 1.05 g/g from arid air (25°C and 30% RH) • The limitation of tailor-made materials for specific conditions is weakened • Variable weather is no longer an obstacle to the implementation of AWH By inducing a cooling source in the adsorption phase, Feng et al. propose a regulation strategy of sorbent stepwise position without changing any innate properties of MOFs, turning the impossibility of water harvesting into a possibility when ambient RH is beyond the operational humidity range of materials.