Sorption-based atmospheric water harvesters - perspectives on materials design and innovation

Atmospheric water harvesting (AWH) has gained significant attention as an alternative solution to tackle global water scarcity by capturing moisture present in the air. Unlike traditional water sources, AWH has the advantage of being geographically versatile and implementable across both highly populated and decentralized settings. Sorption-based AWH (SAWH) systems are economical and able to operate at a wide range of environmental relative humidity and temperature. The development of specifically engineered and scalable materials has been pursued to enable greater capture capacity and lower energy for regeneration and water recovery. In this review, the development of novel hybrid materials, the exploration of sustainable and eco-friendly AWH options, and the integration of advanced technologies such as those involving thermo-responsive and biomimicking materials are discussed. Besides, this review presents a critical assessment of design requirements based on the most promising materials developed for SAWH to date. A particular focus is set on the importance of controlling surfaces and interface wettability as well as macro-porous structures to enhance the performance and enable cost competitive AWH. The advantages and limitations of different sorbent materials are also highlighted, providing insights into their applicability and potential for large-scale implementation. • Assessment of properties required for atmospheric water harvesting. • Discussion on current benchmark materials for high moisture capture capacity. • Evaluation of challenges related to scalability and regeneration costs. • Strategic recommendations towards nano/micro engineering routes.