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

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.