Hierarchical porous metal–organic gels and derived materials: from fundamentals to potential applications

Abstract

This review summarizes recent progress in the development and applications of metal–organic gels (MOGs) and their hybrids and derivatives dividing them into subclasses and discussing their synthesis, design and structure–property relationship.

Raman spectroscopy, an ideal tool for studying the physical properties and applications of metal–organic frameworks (MOFs)

“…5 Such flexibility makes MOFs susceptible to structural transitions due to guest adsorption/desorption, temperature, pressure, electric field, magnetic field, light, etc., [6][7][8] which enables their applications in gas storage, hydrocarbon separation, catalysis, energy storage, biomedicine, sensors, and magnetic materials. [9][10][11][12][13][14][15][16][17][18] To date, more than 100 000 MOFs have been reported, having a wide range of crystal structures, framework flexibility, and stability (Fig. 1).…”

“…16,17 Even though numerous MOFs have been reported, many of them have stability issues and cannot withstand high temperatures, high pressures, or extreme chemical conditions. 18,23,24 Besides, the structural stability of MOFs also decreases with the increasing length of aromatic linkers, such as those present in interpenetrated MOFs. This issue is addressed in the 3D MOFs consisting of Zr 6 (O) 4 (OH) 4 clusters and aromatic carboxylic acids, known as UiO-MOFs (University of Oslo), such as UiO-66, UiO-67, UiO-68, and UiO-69, which have significantly high stability.…”

“…25 The flexible MIL-47(V) framework is a flexible structure built from infinite (V-O-V) n chains linked with benzene-1,4-dicarboxylic acid, with large specific surface area, high thermal stability and superior catalytic properties. 18,23,24 Further, MOF-508 is a mixed linker MOF where Zn(II) metals are coordinated to 1,4-benzenedicarboxylate to form distorted 2D grids, which are then pillared with 4,4 0 -bipyridine (bipy) molecules, leading to an interpenetrated framework and a pore size of 4.0 Â 4.0 Å 2 . 26 This MOF shows interesting framework dynamics with addition or removal of guest molecules, but lacks stability under extreme conditions.…”

“…, 6–8 which enables their applications in gas storage, hydrocarbon separation, catalysis, energy storage, biomedicine, sensors, and magnetic materials. 9–18…”

Robust DUT-67 material for highly efficient removal of the Cr(VI) ion from an aqueous solution

“…In recent years, porous materials such as large-pore resin, activated carbon, metal-organic frameworks (MOFs), natural zeolite, silica gel, molecular sieve, and covalent organic frameworks have significantly advanced in the field of adsorption and they interact favorably during separation and purification (Peng, et al, 2018;Wychowaniec et al, 2022). Metal-organic frameworks have high porosity, large surface area, high stability, and simple preparation when compared with the traditional porous materials (Bai et al, 2016;Zhang et al, 2021).…”