Reticular Chemistry in Action: A Hydrolytically Stable MOF Capturing Twice Its Weight in Adsorbed Water

Abstract

Hydrolytically stable adsorbents, with notable water uptake, are of prime importance and offer great potential for many water-adsorption-related applications. Nevertheless, deliberate construction of tunable porous solids with high porosity and high stability remains challenging. Here, we present the successful deployment of reticular chemistry to address this demand: we constructed Cr-soc-MOF-1, a chemically and hydrolytically stable chromium-based metal-organic framework (MOF) with underlying soc topology. Prominently, Cr-soc-MOF-1 offers the requisite thermal and chemical stability concomitant with unique adsorption properties, namely extraordinary high porosity (apparent surface area of 4,549 m2/g) affording a water vapor uptake of 1.95 g/g at 70% relative humidity. This exceptional water uptake is maintained over more than 100 adsorption-desorption cycles. Markedly, the adsorbed water can be fully desorbed by just the simple reduction of the relative humidity at 25°C. Cr-soc-MOF-1 offers great potential for use in applications pertaining to water vapor control in enclosed and confined spaces and dehumidification. The ability to design and construct advanced adsorbent materials with the requisite hydrolytic stability and concurrent ultra-high porosity, affording exceptional adsorbed water uptake with distinct S-shape adsorption-desorption isotherms, will permit the successful deployment of made-to-order adsorbents for water-adsorption-related applications such as moisture control, dehumidification, adsorption-based desalination, and adsorption heating and cooling pumps. Successful positioning of these applications offers great potential to address various United Nations Sustainable Development Goals pertaining to affordable clean water, prosperous health, and reliable and sustainable energy-efficient air-conditioning technologies. Here, we unveil a hydrolytically stable and highly porous MOF, Cr-soc-MOF-1, as a unique adsorbent material for water adsorption applications. Prominently, Cr-soc-MOF-1 captures twice its weight and can address many acute societal and industrial challenges. Hydrolytically stable and highly porous Cr-soc-MOF-1 can capture 200 wt % of water. The exceptional water uptake is maintained over more than 100 adsorption-desorption cycles. Cr-soc-MOF-1 adsorbent can find potential use for water adsorption-related applications such as moisture control, dehumidification, adsorption-based desalination, and adsorption heating and cooling pumps.