Researchers have developed a metal-organic material (MOM) that can capture water from the air. They published their findings in the Journal of the American Chemical Society. Materials like this could be critical to combating global water scarcity, the paper stated.
Credit: J. Am. Chem. Soc. 2026, DOI: 10.1021/jacs.6c01019
According to the United Nations, water stress levels reached 18.6% in 2021, rising 2.8% globally since 2015. Approximately 10% of the global population lives in countries with high and critical water stress levels.
The paper describes an MOM with a topology based on a condensed primitive cubic lattice that captures atmospheric water upon UV irradiation. The material is a crystalline network of cadmium-metal centers connected by linkers that contain carbon-carbon double bonds.
Upon exposure to UV light, cycloaddition creates isolated, well-defined cavities in the material that spontaneously trap atmospheric water as discrete, hydrogen-bonded dimers within the crystal. The transformation expands the cavities within the material by 3%, even as the underlying crystalline cubic structure is preserved.
Molecular dynamics simulations showed that the hydrogen-bonded dimers persisted over time, remaining hydrogen-bonded to one another. Density functional theory calculations demonstrated that water uptake into the photogenerated cavities is thermodynamically favorable.
The water captured in the material can be released by applying heat. The water is held by intermolecular interactions, mainly hydrogen bonds, which easily break under heat.
The use of cadmium could become a hindrance to the scaling of this material, however, because it is highly toxic and has been known to cause lung disease, cancer and genetic toxicity. Its half-life in the human body ranges from 16 to 30 years. It may be possible to use zinc, zirconium or titanium analogs for the metal centers instead.
The researchers state that photostability and chemical durability tests are essential before the material can be considered for practical applications.
