Record Atmospheric Fresh Water Capture and Heat Transfer with a Material Operating at the Water Uptake Reversibility Limit

[Image: see text] The capture of water vapor at low relative humidity is desirable for producing potable water in desert regions and for heat transfer and storage. Here, we report a mesoporous metal–organic framework that captures 82% water by weight below 30% relative humidity. Under simulated desert conditions, the sorbent would deliver 0.82 g(H2O) g(MOF)(–1), nearly double the quantity of fresh water compared to the previous best material. The material further demonstrates a cooling capacity of 400 kWh m(–3) per cycle, also a record value for a sorbent capable of creating a 20 °C difference between ambient and output temperature. The water uptake in this sorbent is optimized: the pore diameter of our material is above the critical diameter for water capillary action, enabling water uptake at the limit of reversibility.