UC Davis

Water scarcity is one of the greatest global challenges at this time. Significant efforts have been made to harvest water from the air, due to widely available water sources present in the atmosphere. Particularly, solar-driven hygroscopic water harvesting based on the adsorption-desorption process has gained tremendous attention because of the abundance of solar energy in combination with substantial improvements in conversion efficiency enabled by advanced sorbents, improved photothermal materials, interfacial heating system designs, and thermal management in recent years. Here, recent developments in atmospheric water harvesting are discussed, with a focus on solar-driven hygroscopic water harvesting. The diverse structural designs and engineering strategies that are being used to improve the rate of the water production, including the design principles for sorbents with high adsorption capacity, high-efficiency light-to-heat conversion, optimization of thermal management, vapor condensation, and water collection, are also explored. The current challenges and future research opportunities are also discussed, providing a roadmap for the future development of solar-driven hygroscopic water harvesting technology.