Static and Dynamic Adsorptions of Water Vapor by Cyclic [Zr₃₆] Clusters: Implications for Atmospheric Water Capture Using Molecular Solids

Abstract

A 36-nuclear Zr(IV) cluster based on six [Zr 6 O 4 (OH) 4 ] units is found to form three different crystal structures depending on synthesis conditions. The cubic phase (ZF-3c) is obtained when the cyclic clusters are interlinked by Na + or K + ions. In the absence of alkali metal ions, either tetragonal (ZF-3t) or hexagonal (ZF-3h) packing structures are formed. All the solids remain crystalline after evacuation, and ZF-3h possesses a permanent porosity. Upon repeated adsorptions of water vapor, the three different molecular solids comprising the same building blocks turn amorphous; however, overall uptake properties are not deteriorated and reproducible isotherms are observed featuring fast uptake at low relative humidity and unrestricted uptake at RH > 90%. A good reproducibility has also been established in cyclic adsorptiondesorption measured under dynamic flow conditions, and, especially ZF-3t displays the working capacity 2.7 times that of zeolite 4A thanks to the fast desorption kinetics.

Effect of Functional Groups on the I2 Sorption Kinetics of Isostructural Metal–Organic Frameworks

“…Metal-organic frameworks (MOFs) are promising adsorbents for I 2 capture because of their large surface areas and easy structural tunability. [6][7][8][9][10][11] Various MOFs such as HKUST-1, 12 ZIF-8, [13][14][15][16] UiO-66 series, 17 MIL series, 18 MFM-300 series, 19 Tb-MOF, 20 and SBMOF 21 have been evaluated for I 2 capture. To design an ideal MOF sorbent, the interactions of the adsorbed I 2 molecules with the building blocks of MOFs must be enhanced.…”

Modified Metal–Organic Frameworks as Efficient Catalysts for Lignocellulosic Biomass Conversion

“…The CUSs participate in the catalytic reaction as Lewis acid sites and bind reactants. 26,29,30,48 However, when the CN is high, many donor atoms are bonded to the metal nodes, making it difficult for metal ions to bind to the reactant during a catalytic reaction. Therefore, it is very important to modify MOFs to achieve a low CN and increase the number of potential binding sites of the central metal.…”

Heterojunction of Pores in Granola‐Type Crystals of Two Different Metal–Organic Frameworks for Enhanced Formaldehyde Removal

“…Heterogeneous structures typically exist in nature, providing unique functions for the introduction of ingredients, moisture, and other guest molecules. Synthetic materials have been chasing the introduction of heterogeneity by intermingling different units together within a single body, giving rise to new functions that cannot be realized with a single material (1)(2)(3)(4)(5)(6)(7)(8). Metal-organic frameworks (MOFs) are synthetic and crystalline materials with homogeneous pores, which are advantageous for designing a pore environment to have desired properties (9)(10)(11).…”