Surface area determination with the Brunauer–Emmett–Teller (BET) method is a widely used characterization technique for metal–organic frameworks (MOFs). Since these materials are highly porous, the use of the BET theory can be problematic. Several researchers have evaluated the BET method to gain insights into the usefulness of the obtained results and interestingly, their findings are not always consistent. In this review, the suitability of the BET method is discussed for MOFs that have a diverse range of pore widths below the diameters of N2 or Ar and above 20 Å. In addition, the surface area of MOFs that are obtained by implementing different approaches, such as grand canonical Monte Carlo simulations, calculations from the crystal structures or based on experimental N2, Ar, or CO2 adsorption isotherms, are compared and evaluated. Inconsistencies in the state‐of‐the‐art are also noted. Based on the current literature, an overview is provided of how the BET method can give useful estimations of the surface areas for the majority of MOFs, but there are some crucial and specific exceptions which are highlighted in this review.

Metal−organic frameworks (MOFs) are some of the most interesting and promising candidates to sequester toxic H 2 S and SO 2 gases. MOFs show interesting advantages over classic porous materials due to their chemical composition, ligand functionality, cavity dimensions, ease of preparation, and relatively low cost reactivation. The optimization of the physical−chemical interactions between MOFs and H 2 S and SO 2 molecules is the key to further amplification of their capture. Reversibility after the adsorption of H 2 S and SO 2 can be modulated through noncovalent bonding between functionalized ligands (within MOF structures) and H 2 S and SO 2 . This review aims to summarize recent advances in the development of MOF-based systems for the capture and removal of H 2 S and SO 2 . We anticipate that this review article can offer very useful information on the significant and rapid progress of the enhancement of H 2 S and SO 2 capture by MOFs.

MIL-101(Cr)-4F(1%) shows a high uptake and high chemical stability to dry and humid SO2 and a remarkable cyclability. In situ DRIF spectroscopy upon the adsorption of CO identified the preferential adsorption sites for this MOF material.

Postsynthetic functionalization of magnesium 2,5-dihydroxyterephthalate (Mg-MOF-74) with tetraethylenepentamine (TEPA) resulted in improved CO adsorption performance under dry and humid conditions. XPS, elemental analysis, and neutron powder diffraction studies indicated that TEPA was incorporated throughout the MOF particle, although it coordinated preferentially with the unsaturated metal sites located in the immediate proximity to the surface. Neutron and X-ray powder diffraction analyses showed that the MOF structure was preserved after amine incorporation, with slight changes in the lattice parameters. The adsorption capacity of the functionalized amino-Mg-MOF-74 (TEPA-MOF) for CO was as high as 26.9 wt % versus 23.4 wt % for the original MOF due to the extra binding sites provided by the multiunit amines. The degree of functionalization with the amines was found to be important in enhancing CO adsorption, as the optimal surface coverage improved performance and stability under both pure CO and CO/HO coadsorption, and with partially saturated surface coverage, optimal CO capacity could be achieved under both wet and dry conditions by a synergistic binding of CO to the amines as well as metal centers.

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Metal−organic frameworks MIL-53(Al)-TDC and MIL-53(Al)-BDC were explored in the SO 2 adsorption process. MIL-53(Al)-TDC was shown to behave as a rigid-like material upon SO 2 adsorption. On the other hand, MIL-53(Al)-BDC exhibits guest-induced flexibility of the framework with the presence of multiple steps in the SO 2 adsorption isotherm that was related through molecular simulations to the existence of three different pore opening phases narrow pore, intermediate pore, and large pore. Both materials proved to be exceptional candidates for SO 2 capture, even under wet conditions, with excellent SO 2 adsorption, good cycling, chemical stability, and easy regeneration. Further, we propose MIL-53(Al)-TDC and MIL-53(A)-BDC of potential interest for SO 2 sensing and SO 2 storage/transportation, respectively.

MFM-300(Sc) was demonstrated to be an optimal adsorbent for SO2 capture combining high uptake, good stability and excellent cyclability (facile regeneration at only room temperature). A drastic enhancement on its SO2 uptake (40%) was achieved when a small amount of EtOH was preliminary adsorbed.

Combination of in situ Raman scattering with high-resolution XRD and XAS techniques has proven to be a powerful tool to elucidate the crystal growth of gamma-Bi2MoO6 under hydrothermal conditions.