Materials Engineering for Atmospheric Water Harvesting: Progress and Perspectives

Atmospheric water harvesting (AWH) is emerging as a promising strategy to produce fresh water from abundant airborne moisture to overcome the global clean water shortage. The ubiquitous moisture resources allow AWH to be free from geographical restrictions and potentially realize decentralized applications, making it a vital parallel or supplementary freshwater production approach to liquid water resource‐based technologies. Recent advances in regulating chemical properties and micro/nanostructures of moisture‐harvesting materials have demonstrated new possibilities to promote enhanced device performance and new understandings. This perspective aims to provide a timely overview on the state‐of‐the‐art materials design and how they serve as the active components in AWH. First, the key processes of AWH, including vapor condensation, droplet nucleation, growth, and departure are outlined, and the desired material properties based on the fundamental mechanisms are discussed. Then, how tailoring materials‐water interactions at the molecular level play a vital role in realizing high water uptake and low energy consumption is shown. Last, the challenges and outlook on further improving AWH from material designs and system engineering aspects are highlighted. Recent advancements in material and architecture engineering of air‐water‐harvesting materials have promoted remarkable progress toward the atmospheric water harvesting (AWH) technology. This perspective discusses the fundamental insights of how different material designs affect the water‐material interactions in advancing AWH technology.